Lots of RISC-V improvements.

[fw/openocd] / src / target / riscv / riscv.c

#include <assert.h>
#include <stdlib.h>
#include <time.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "target/target.h"
#include "target/algorithm.h"
#include "target/target_type.h"
#include "log.h"
#include "jtag/jtag.h"
#include "target/register.h"
#include "target/breakpoints.h"
#include "helper/time_support.h"
#include "riscv.h"
#include "gdb_regs.h"
#include "rtos/rtos.h"

/**
 * Since almost everything can be accomplish by scanning the dbus register, all
 * functions here assume dbus is already selected. The exception are functions
 * called directly by OpenOCD, which can't assume anything about what's
 * currently in IR. They should set IR to dbus explicitly.
 */

/**
 * Code structure
 *
 * At the bottom of the stack are the OpenOCD JTAG functions:
 *              jtag_add_[id]r_scan
 *              jtag_execute_query
 *              jtag_add_runtest
 *
 * There are a few functions to just instantly shift a register and get its
 * value:
 *              dtmcontrol_scan
 *              idcode_scan
 *              dbus_scan
 *
 * Because doing one scan and waiting for the result is slow, most functions
 * batch up a bunch of dbus writes and then execute them all at once. They use
 * the scans "class" for this:
 *              scans_new
 *              scans_delete
 *              scans_execute
 *              scans_add_...
 * Usually you new(), call a bunch of add functions, then execute() and look
 * at the results by calling scans_get...()
 *
 * Optimized functions will directly use the scans class above, but slightly
 * lazier code will use the cache functions that in turn use the scans
 * functions:
 *              cache_get...
 *              cache_set...
 *              cache_write
 * cache_set... update a local structure, which is then synced to the target
 * with cache_write(). Only Debug RAM words that are actually changed are sent
 * to the target. Afterwards use cache_get... to read results.
 */

#define get_field(reg, mask) (((reg) & (mask)) / ((mask) & ~((mask) << 1)))
#define set_field(reg, mask, val) (((reg) & ~(mask)) | (((val) * ((mask) & ~((mask) << 1))) & (mask)))

#define DIM(x)          (sizeof(x)/sizeof(*x))

/* Constants for legacy SiFive hardware breakpoints. */
#define CSR_BPCONTROL_X                 (1<<0)
#define CSR_BPCONTROL_W                 (1<<1)
#define CSR_BPCONTROL_R                 (1<<2)
#define CSR_BPCONTROL_U                 (1<<3)
#define CSR_BPCONTROL_S                 (1<<4)
#define CSR_BPCONTROL_H                 (1<<5)
#define CSR_BPCONTROL_M                 (1<<6)
#define CSR_BPCONTROL_BPMATCH   (0xf<<7)
#define CSR_BPCONTROL_BPACTION  (0xff<<11)

#define DEBUG_ROM_START         0x800
#define DEBUG_ROM_RESUME        (DEBUG_ROM_START + 4)
#define DEBUG_ROM_EXCEPTION     (DEBUG_ROM_START + 8)
#define DEBUG_RAM_START         0x400

#define SETHALTNOT                              0x10c

/*** JTAG registers. ***/

#define DTMCONTROL                                      0x10
#define DTMCONTROL_DBUS_RESET           (1<<16)
#define DTMCONTROL_IDLE                         (7<<10)
#define DTMCONTROL_ADDRBITS                     (0xf<<4)
#define DTMCONTROL_VERSION                      (0xf)

#define DBUS                                            0x11
#define DBUS_OP_START                           0
#define DBUS_OP_SIZE                            2
typedef enum {
        DBUS_OP_NOP = 0,
        DBUS_OP_READ = 1,
        DBUS_OP_WRITE = 2
} dbus_op_t;
typedef enum {
        DBUS_STATUS_SUCCESS = 0,
        DBUS_STATUS_FAILED = 2,
        DBUS_STATUS_BUSY = 3
} dbus_status_t;
#define DBUS_DATA_START                         2
#define DBUS_DATA_SIZE                          34
#define DBUS_ADDRESS_START                      36

typedef enum {
        RE_OK,
        RE_FAIL,
        RE_AGAIN
} riscv_error_t;

typedef enum slot {
        SLOT0,
        SLOT1,
        SLOT_LAST,
} slot_t;

/*** Debug Bus registers. ***/

#define DMCONTROL                               0x10
#define DMCONTROL_INTERRUPT             (((uint64_t)1)<<33)
#define DMCONTROL_HALTNOT               (((uint64_t)1)<<32)
#define DMCONTROL_BUSERROR              (7<<19)
#define DMCONTROL_SERIAL                (3<<16)
#define DMCONTROL_AUTOINCREMENT (1<<15)
#define DMCONTROL_ACCESS                (7<<12)
#define DMCONTROL_HARTID                (0x3ff<<2)
#define DMCONTROL_NDRESET               (1<<1)
#define DMCONTROL_FULLRESET             1

#define DMINFO                                  0x11
#define DMINFO_ABUSSIZE                 (0x7fU<<25)
#define DMINFO_SERIALCOUNT              (0xf<<21)
#define DMINFO_ACCESS128                (1<<20)
#define DMINFO_ACCESS64                 (1<<19)
#define DMINFO_ACCESS32                 (1<<18)
#define DMINFO_ACCESS16                 (1<<17)
#define DMINFO_ACCESS8                  (1<<16)
#define DMINFO_DRAMSIZE                 (0x3f<<10)
#define DMINFO_AUTHENTICATED    (1<<5)
#define DMINFO_AUTHBUSY                 (1<<4)
#define DMINFO_AUTHTYPE                 (3<<2)
#define DMINFO_VERSION                  3

/*** Info about the core being debugged. ***/

#define DBUS_ADDRESS_UNKNOWN    0xffff

#define MAX_HWBPS                       16
#define DRAM_CACHE_SIZE         16

uint8_t ir_dtmcontrol[4] = {DTMCONTROL};
struct scan_field select_dtmcontrol = {
        .in_value = NULL,
        .out_value = ir_dtmcontrol
};
uint8_t ir_dbus[4] = {DBUS};
struct scan_field select_dbus = {
        .in_value = NULL,
        .out_value = ir_dbus
};
uint8_t ir_idcode[4] = {0x1};
struct scan_field select_idcode = {
        .in_value = NULL,
        .out_value = ir_idcode
};

struct trigger {
        uint64_t address;
        uint32_t length;
        uint64_t mask;
        uint64_t value;
        bool read, write, execute;
        int unique_id;
};

/* Wall-clock timeout for a command/access. Settable via RISC-V Target commands.*/
int riscv_command_timeout_sec = DEFAULT_COMMAND_TIMEOUT_SEC;

/* Wall-clock timeout after reset. Settable via RISC-V Target commands.*/
int riscv_reset_timeout_sec = DEFAULT_RESET_TIMEOUT_SEC;

bool riscv_prefer_sba;

typedef struct {
        uint16_t low, high;
} range_t;

/* In addition to the ones in the standard spec, we'll also expose additional
 * CSRs in this list.
 * The list is either NULL, or a series of ranges (inclusive), terminated with
 * 1,0. */
range_t *expose_csr;
/* Same, but for custom registers. */
range_t *expose_custom;

static uint32_t dtmcontrol_scan(struct target *target, uint32_t out)
{
        struct scan_field field;
        uint8_t in_value[4];
        uint8_t out_value[4];

        buf_set_u32(out_value, 0, 32, out);

        jtag_add_ir_scan(target->tap, &select_dtmcontrol, TAP_IDLE);

        field.num_bits = 32;
        field.out_value = out_value;
        field.in_value = in_value;
        jtag_add_dr_scan(target->tap, 1, &field, TAP_IDLE);

        /* Always return to dbus. */
        jtag_add_ir_scan(target->tap, &select_dbus, TAP_IDLE);

        int retval = jtag_execute_queue();
        if (retval != ERROR_OK) {
                LOG_ERROR("failed jtag scan: %d", retval);
                return retval;
        }

        uint32_t in = buf_get_u32(field.in_value, 0, 32);
        LOG_DEBUG("DTMCONTROL: 0x%x -> 0x%x", out, in);

        return in;
}

static struct target_type *get_target_type(struct target *target)
{
        riscv_info_t *info = (riscv_info_t *) target->arch_info;

        if (!info) {
                LOG_ERROR("Target has not been initialized");
                return NULL;
        }

        switch (info->dtm_version) {
                case 0:
                        return &riscv011_target;
                case 1:
                        return &riscv013_target;
                default:
                        LOG_ERROR("Unsupported DTM version: %d", info->dtm_version);
                        return NULL;
        }
}

static int riscv_init_target(struct command_context *cmd_ctx,
                struct target *target)
{
        LOG_DEBUG("riscv_init_target()");
        target->arch_info = calloc(1, sizeof(riscv_info_t));
        if (!target->arch_info)
                return ERROR_FAIL;
        riscv_info_t *info = (riscv_info_t *) target->arch_info;
        riscv_info_init(target, info);
        info->cmd_ctx = cmd_ctx;

        select_dtmcontrol.num_bits = target->tap->ir_length;
        select_dbus.num_bits = target->tap->ir_length;
        select_idcode.num_bits = target->tap->ir_length;

        riscv_semihosting_init(target);

        target->debug_reason = DBG_REASON_DBGRQ;

        return ERROR_OK;
}

static void riscv_deinit_target(struct target *target)
{
        LOG_DEBUG("riscv_deinit_target()");
        struct target_type *tt = get_target_type(target);
        if (tt) {
                tt->deinit_target(target);
                riscv_info_t *info = (riscv_info_t *) target->arch_info;
                free(info->reg_names);
                free(info);
        }
        /* Free the shared structure use for most registers. */
        if (target->reg_cache) {
                if (target->reg_cache->reg_list) {
                        if (target->reg_cache->reg_list[0].arch_info)
                                free(target->reg_cache->reg_list[0].arch_info);
                        /* Free the ones we allocated separately. */
                        for (unsigned i = GDB_REGNO_COUNT; i < target->reg_cache->num_regs; i++)
                                free(target->reg_cache->reg_list[i].arch_info);
                        free(target->reg_cache->reg_list);
                }
                free(target->reg_cache);
        }
        target->arch_info = NULL;
}

static int oldriscv_halt(struct target *target)
{
        struct target_type *tt = get_target_type(target);
        return tt->halt(target);
}

static void trigger_from_breakpoint(struct trigger *trigger,
                const struct breakpoint *breakpoint)
{
        trigger->address = breakpoint->address;
        trigger->length = breakpoint->length;
        trigger->mask = ~0LL;
        trigger->read = false;
        trigger->write = false;
        trigger->execute = true;
        /* unique_id is unique across both breakpoints and watchpoints. */
        trigger->unique_id = breakpoint->unique_id;
}

static int maybe_add_trigger_t1(struct target *target, unsigned hartid,
                struct trigger *trigger, uint64_t tdata1)
{
        RISCV_INFO(r);

        const uint32_t bpcontrol_x = 1<<0;
        const uint32_t bpcontrol_w = 1<<1;
        const uint32_t bpcontrol_r = 1<<2;
        const uint32_t bpcontrol_u = 1<<3;
        const uint32_t bpcontrol_s = 1<<4;
        const uint32_t bpcontrol_h = 1<<5;
        const uint32_t bpcontrol_m = 1<<6;
        const uint32_t bpcontrol_bpmatch = 0xf << 7;
        const uint32_t bpcontrol_bpaction = 0xff << 11;

        if (tdata1 & (bpcontrol_r | bpcontrol_w | bpcontrol_x)) {
                /* Trigger is already in use, presumably by user code. */
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        tdata1 = set_field(tdata1, bpcontrol_r, trigger->read);
        tdata1 = set_field(tdata1, bpcontrol_w, trigger->write);
        tdata1 = set_field(tdata1, bpcontrol_x, trigger->execute);
        tdata1 = set_field(tdata1, bpcontrol_u,
                        !!(r->misa[hartid] & (1 << ('U' - 'A'))));
        tdata1 = set_field(tdata1, bpcontrol_s,
                        !!(r->misa[hartid] & (1 << ('S' - 'A'))));
        tdata1 = set_field(tdata1, bpcontrol_h,
                        !!(r->misa[hartid] & (1 << ('H' - 'A'))));
        tdata1 |= bpcontrol_m;
        tdata1 = set_field(tdata1, bpcontrol_bpmatch, 0); /* exact match */
        tdata1 = set_field(tdata1, bpcontrol_bpaction, 0); /* cause bp exception */

        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, tdata1);

        riscv_reg_t tdata1_rb;
        if (riscv_get_register_on_hart(target, &tdata1_rb, hartid,
                                GDB_REGNO_TDATA1) != ERROR_OK)
                return ERROR_FAIL;
        LOG_DEBUG("tdata1=0x%" PRIx64, tdata1_rb);

        if (tdata1 != tdata1_rb) {
                LOG_DEBUG("Trigger doesn't support what we need; After writing 0x%"
                                PRIx64 " to tdata1 it contains 0x%" PRIx64,
                                tdata1, tdata1_rb);
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, 0);
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA2, trigger->address);

        return ERROR_OK;
}

static int maybe_add_trigger_t2(struct target *target, unsigned hartid,
                struct trigger *trigger, uint64_t tdata1)
{
        RISCV_INFO(r);

        /* tselect is already set */
        if (tdata1 & (MCONTROL_EXECUTE | MCONTROL_STORE | MCONTROL_LOAD)) {
                /* Trigger is already in use, presumably by user code. */
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        /* address/data match trigger */
        tdata1 |= MCONTROL_DMODE(riscv_xlen(target));
        tdata1 = set_field(tdata1, MCONTROL_ACTION,
                        MCONTROL_ACTION_DEBUG_MODE);
        tdata1 = set_field(tdata1, MCONTROL_MATCH, MCONTROL_MATCH_EQUAL);
        tdata1 |= MCONTROL_M;
        if (r->misa[hartid] & (1 << ('H' - 'A')))
                tdata1 |= MCONTROL_H;
        if (r->misa[hartid] & (1 << ('S' - 'A')))
                tdata1 |= MCONTROL_S;
        if (r->misa[hartid] & (1 << ('U' - 'A')))
                tdata1 |= MCONTROL_U;

        if (trigger->execute)
                tdata1 |= MCONTROL_EXECUTE;
        if (trigger->read)
                tdata1 |= MCONTROL_LOAD;
        if (trigger->write)
                tdata1 |= MCONTROL_STORE;

        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, tdata1);

        uint64_t tdata1_rb;
        int result = riscv_get_register_on_hart(target, &tdata1_rb, hartid, GDB_REGNO_TDATA1);
        if (result != ERROR_OK)
                return result;
        LOG_DEBUG("tdata1=0x%" PRIx64, tdata1_rb);

        if (tdata1 != tdata1_rb) {
                LOG_DEBUG("Trigger doesn't support what we need; After writing 0x%"
                                PRIx64 " to tdata1 it contains 0x%" PRIx64,
                                tdata1, tdata1_rb);
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, 0);
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA2, trigger->address);

        return ERROR_OK;
}

static int add_trigger(struct target *target, struct trigger *trigger)
{
        RISCV_INFO(r);

        if (riscv_enumerate_triggers(target) != ERROR_OK)
                return ERROR_FAIL;

        /* In RTOS mode, we need to set the same trigger in the same slot on every
         * hart, to keep up the illusion that each hart is a thread running on the
         * same core. */

        /* Otherwise, we just set the trigger on the one hart this target deals
         * with. */

        riscv_reg_t tselect[RISCV_MAX_HARTS];

        int first_hart = -1;
        for (int hartid = 0; hartid < riscv_count_harts(target); ++hartid) {
                if (!riscv_hart_enabled(target, hartid))
                        continue;
                if (first_hart < 0)
                        first_hart = hartid;
                int result = riscv_get_register_on_hart(target, &tselect[hartid],
                                hartid, GDB_REGNO_TSELECT);
                if (result != ERROR_OK)
                        return result;
        }
        assert(first_hart >= 0);

        unsigned int i;
        for (i = 0; i < r->trigger_count[first_hart]; i++) {
                if (r->trigger_unique_id[i] != -1)
                        continue;

                riscv_set_register_on_hart(target, first_hart, GDB_REGNO_TSELECT, i);

                uint64_t tdata1;
                int result = riscv_get_register_on_hart(target, &tdata1, first_hart,
                                GDB_REGNO_TDATA1);
                if (result != ERROR_OK)
                        return result;
                int type = get_field(tdata1, MCONTROL_TYPE(riscv_xlen(target)));

                result = ERROR_OK;
                for (int hartid = first_hart; hartid < riscv_count_harts(target); ++hartid) {
                        if (!riscv_hart_enabled(target, hartid))
                                continue;
                        if (hartid > first_hart)
                                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT, i);
                        switch (type) {
                                case 1:
                                        result = maybe_add_trigger_t1(target, hartid, trigger, tdata1);
                                        break;
                                case 2:
                                        result = maybe_add_trigger_t2(target, hartid, trigger, tdata1);
                                        break;
                                default:
                                        LOG_DEBUG("trigger %d has unknown type %d", i, type);
                                        continue;
                        }

                        if (result != ERROR_OK)
                                continue;
                }

                if (result != ERROR_OK)
                        continue;

                LOG_DEBUG("[%d] Using trigger %d (type %d) for bp %d", target->coreid,
                                i, type, trigger->unique_id);
                r->trigger_unique_id[i] = trigger->unique_id;
                break;
        }

        for (int hartid = first_hart; hartid < riscv_count_harts(target); ++hartid) {
                if (!riscv_hart_enabled(target, hartid))
                        continue;
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT,
                                tselect[hartid]);
        }

        if (i >= r->trigger_count[first_hart]) {
                LOG_ERROR("Couldn't find an available hardware trigger.");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        return ERROR_OK;
}

int riscv_add_breakpoint(struct target *target, struct breakpoint *breakpoint)
{
        LOG_DEBUG("[%d] @0x%" TARGET_PRIxADDR, target->coreid, breakpoint->address);
        assert(breakpoint);
        if (breakpoint->type == BKPT_SOFT) {
                /** @todo check RVC for size/alignment */
                if (!(breakpoint->length == 4 || breakpoint->length == 2)) {
                        LOG_ERROR("Invalid breakpoint length %d", breakpoint->length);
                        return ERROR_FAIL;
                }

                if (0 != (breakpoint->address % 2)) {
                        LOG_ERROR("Invalid breakpoint alignment for address 0x%" TARGET_PRIxADDR, breakpoint->address);
                        return ERROR_FAIL;
                }

                if (target_read_memory(target, breakpoint->address, 2, breakpoint->length / 2,
                                        breakpoint->orig_instr) != ERROR_OK) {
                        LOG_ERROR("Failed to read original instruction at 0x%" TARGET_PRIxADDR,
                                        breakpoint->address);
                        return ERROR_FAIL;
                }

                uint8_t buff[4];
                buf_set_u32(buff, 0, breakpoint->length * CHAR_BIT, breakpoint->length == 4 ? ebreak() : ebreak_c());
                int const retval = target_write_memory(target, breakpoint->address, 2, breakpoint->length / 2, buff);

                if (retval != ERROR_OK) {
                        LOG_ERROR("Failed to write %d-byte breakpoint instruction at 0x%"
                                        TARGET_PRIxADDR, breakpoint->length, breakpoint->address);
                        return ERROR_FAIL;
                }

        } else if (breakpoint->type == BKPT_HARD) {
                struct trigger trigger;
                trigger_from_breakpoint(&trigger, breakpoint);
                int const result = add_trigger(target, &trigger);
                if (result != ERROR_OK)
                        return result;
        } else {
                LOG_INFO("OpenOCD only supports hardware and software breakpoints.");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        breakpoint->set = true;
        return ERROR_OK;
}

static int remove_trigger(struct target *target, struct trigger *trigger)
{
        RISCV_INFO(r);

        if (riscv_enumerate_triggers(target) != ERROR_OK)
                return ERROR_FAIL;

        int first_hart = -1;
        for (int hartid = 0; hartid < riscv_count_harts(target); ++hartid) {
                if (!riscv_hart_enabled(target, hartid))
                        continue;
                if (first_hart < 0) {
                        first_hart = hartid;
                        break;
                }
        }
        assert(first_hart >= 0);

        unsigned int i;
        for (i = 0; i < r->trigger_count[first_hart]; i++) {
                if (r->trigger_unique_id[i] == trigger->unique_id)
                        break;
        }
        if (i >= r->trigger_count[first_hart]) {
                LOG_ERROR("Couldn't find the hardware resources used by hardware "
                                "trigger.");
                return ERROR_FAIL;
        }
        LOG_DEBUG("[%d] Stop using resource %d for bp %d", target->coreid, i,
                        trigger->unique_id);
        for (int hartid = first_hart; hartid < riscv_count_harts(target); ++hartid) {
                if (!riscv_hart_enabled(target, hartid))
                        continue;
                riscv_reg_t tselect;
                int result = riscv_get_register_on_hart(target, &tselect, hartid, GDB_REGNO_TSELECT);
                if (result != ERROR_OK)
                        return result;
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT, i);
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, 0);
                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT, tselect);
        }
        r->trigger_unique_id[i] = -1;

        return ERROR_OK;
}

int riscv_remove_breakpoint(struct target *target,
                struct breakpoint *breakpoint)
{
        if (breakpoint->type == BKPT_SOFT) {
                if (target_write_memory(target, breakpoint->address, 2, breakpoint->length / 2,
                                        breakpoint->orig_instr) != ERROR_OK) {
                        LOG_ERROR("Failed to restore instruction for %d-byte breakpoint at "
                                        "0x%" TARGET_PRIxADDR, breakpoint->length, breakpoint->address);
                        return ERROR_FAIL;
                }

        } else if (breakpoint->type == BKPT_HARD) {
                struct trigger trigger;
                trigger_from_breakpoint(&trigger, breakpoint);
                int result = remove_trigger(target, &trigger);
                if (result != ERROR_OK)
                        return result;

        } else {
                LOG_INFO("OpenOCD only supports hardware and software breakpoints.");
                return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }

        breakpoint->set = false;

        return ERROR_OK;
}

static void trigger_from_watchpoint(struct trigger *trigger,
                const struct watchpoint *watchpoint)
{
        trigger->address = watchpoint->address;
        trigger->length = watchpoint->length;
        trigger->mask = watchpoint->mask;
        trigger->value = watchpoint->value;
        trigger->read = (watchpoint->rw == WPT_READ || watchpoint->rw == WPT_ACCESS);
        trigger->write = (watchpoint->rw == WPT_WRITE || watchpoint->rw == WPT_ACCESS);
        trigger->execute = false;
        /* unique_id is unique across both breakpoints and watchpoints. */
        trigger->unique_id = watchpoint->unique_id;
}

int riscv_add_watchpoint(struct target *target, struct watchpoint *watchpoint)
{
        struct trigger trigger;
        trigger_from_watchpoint(&trigger, watchpoint);

        int result = add_trigger(target, &trigger);
        if (result != ERROR_OK)
                return result;
        watchpoint->set = true;

        return ERROR_OK;
}

int riscv_remove_watchpoint(struct target *target,
                struct watchpoint *watchpoint)
{
        LOG_DEBUG("[%d] @0x%" TARGET_PRIxADDR, target->coreid, watchpoint->address);

        struct trigger trigger;
        trigger_from_watchpoint(&trigger, watchpoint);

        int result = remove_trigger(target, &trigger);
        if (result != ERROR_OK)
                return result;
        watchpoint->set = false;

        return ERROR_OK;
}

/* Sets *hit_watchpoint to the first watchpoint identified as causing the
 * current halt.
 *
 * The GDB server uses this information to tell GDB what data address has
 * been hit, which enables GDB to print the hit variable along with its old
 * and new value. */
int riscv_hit_watchpoint(struct target *target, struct watchpoint **hit_watchpoint)
{
        struct watchpoint *wp = target->watchpoints;

        LOG_DEBUG("Current hartid = %d", riscv_current_hartid(target));

        /*TODO instead of disassembling the instruction that we think caused the
         * trigger, check the hit bit of each watchpoint first. The hit bit is
         * simpler and more reliable to check but as it is optional and relatively
         * new, not all hardware will implement it  */
        riscv_reg_t dpc;
        riscv_get_register(target, &dpc, GDB_REGNO_DPC);
        const uint8_t length = 4;
        LOG_DEBUG("dpc is 0x%" PRIx64, dpc);

        /* fetch the instruction at dpc */
        uint8_t buffer[length];
        if (target_read_buffer(target, dpc, length, buffer) != ERROR_OK) {
                LOG_ERROR("Failed to read instruction at dpc 0x%" PRIx64, dpc);
                return ERROR_FAIL;
        }

        uint32_t instruction = 0;

        for (int i = 0; i < length; i++) {
                LOG_DEBUG("Next byte is %x", buffer[i]);
                instruction += (buffer[i] << 8 * i);
        }
        LOG_DEBUG("Full instruction is %x", instruction);

        /* find out which memory address is accessed by the instruction at dpc */
        /* opcode is first 7 bits of the instruction */
        uint8_t opcode = instruction & 0x7F;
        uint32_t rs1;
        int16_t imm;
        riscv_reg_t mem_addr;

        if (opcode == MATCH_LB || opcode == MATCH_SB) {
                rs1 = (instruction & 0xf8000) >> 15;
                riscv_get_register(target, &mem_addr, rs1);

                if (opcode == MATCH_SB) {
                        LOG_DEBUG("%x is store instruction", instruction);
                        imm = ((instruction & 0xf80) >> 7) | ((instruction & 0xfe000000) >> 20);
                } else {
                        LOG_DEBUG("%x is load instruction", instruction);
                        imm = (instruction & 0xfff00000) >> 20;
                }
                /* sign extend 12-bit imm to 16-bits */
                if (imm & (1 << 11))
                        imm |= 0xf000;
                mem_addr += imm;
                LOG_DEBUG("memory address=0x%" PRIx64, mem_addr);
        } else {
                LOG_DEBUG("%x is not a RV32I load or store", instruction);
                return ERROR_FAIL;
        }

        while (wp) {
                /*TODO support length/mask */
                if (wp->address == mem_addr) {
                        *hit_watchpoint = wp;
                        LOG_DEBUG("Hit address=%" TARGET_PRIxADDR, wp->address);
                        return ERROR_OK;
                }
                wp = wp->next;
        }

        /* No match found - either we hit a watchpoint caused by an instruction that
         * this function does not yet disassemble, or we hit a breakpoint.
         *
         * OpenOCD will behave as if this function had never been implemented i.e.
         * report the halt to GDB with no address information. */
        return ERROR_FAIL;
}


static int oldriscv_step(struct target *target, int current, uint32_t address,
                int handle_breakpoints)
{
        struct target_type *tt = get_target_type(target);
        return tt->step(target, current, address, handle_breakpoints);
}

static int old_or_new_riscv_step(
                struct target *target,
                int current,
                target_addr_t address,
                int handle_breakpoints
){
        RISCV_INFO(r);
        LOG_DEBUG("handle_breakpoints=%d", handle_breakpoints);
        if (r->is_halted == NULL)
                return oldriscv_step(target, current, address, handle_breakpoints);
        else
                return riscv_openocd_step(target, current, address, handle_breakpoints);
}


static int riscv_examine(struct target *target)
{
        LOG_DEBUG("riscv_examine()");
        if (target_was_examined(target)) {
                LOG_DEBUG("Target was already examined.");
                return ERROR_OK;
        }

        /* Don't need to select dbus, since the first thing we do is read dtmcontrol. */

        riscv_info_t *info = (riscv_info_t *) target->arch_info;
        uint32_t dtmcontrol = dtmcontrol_scan(target, 0);
        LOG_DEBUG("dtmcontrol=0x%x", dtmcontrol);
        info->dtm_version = get_field(dtmcontrol, DTMCONTROL_VERSION);
        LOG_DEBUG("  version=0x%x", info->dtm_version);

        struct target_type *tt = get_target_type(target);
        if (tt == NULL)
                return ERROR_FAIL;

        int result = tt->init_target(info->cmd_ctx, target);
        if (result != ERROR_OK)
                return result;

        return tt->examine(target);
}

static int oldriscv_poll(struct target *target)
{
        struct target_type *tt = get_target_type(target);
        return tt->poll(target);
}

static int old_or_new_riscv_poll(struct target *target)
{
        RISCV_INFO(r);
        if (r->is_halted == NULL)
                return oldriscv_poll(target);
        else
                return riscv_openocd_poll(target);
}

static int old_or_new_riscv_halt(struct target *target)
{
        RISCV_INFO(r);
        if (r->is_halted == NULL)
                return oldriscv_halt(target);
        else
                return riscv_openocd_halt(target);
}

static int riscv_assert_reset(struct target *target)
{
        LOG_DEBUG("[%d]", target->coreid);
        struct target_type *tt = get_target_type(target);
        riscv_invalidate_register_cache(target);
        return tt->assert_reset(target);
}

static int riscv_deassert_reset(struct target *target)
{
        LOG_DEBUG("[%d]", target->coreid);
        struct target_type *tt = get_target_type(target);
        return tt->deassert_reset(target);
}


static int oldriscv_resume(struct target *target, int current, uint32_t address,
                int handle_breakpoints, int debug_execution)
{
        struct target_type *tt = get_target_type(target);
        return tt->resume(target, current, address, handle_breakpoints,
                        debug_execution);
}

static int old_or_new_riscv_resume(
                struct target *target,
                int current,
                target_addr_t address,
                int handle_breakpoints,
                int debug_execution
){
        LOG_DEBUG("handle_breakpoints=%d", handle_breakpoints);
        if (target->smp) {
                struct target_list *targets = target->head;
                int result = ERROR_OK;
                while (targets) {
                        struct target *t = targets->target;
                        riscv_info_t *r = riscv_info(t);
                        if (r->is_halted == NULL) {
                                if (oldriscv_resume(t, current, address, handle_breakpoints,
                                                        debug_execution) != ERROR_OK)
                                        result = ERROR_FAIL;
                        } else {
                                if (riscv_openocd_resume(t, current, address,
                                                        handle_breakpoints, debug_execution) != ERROR_OK)
                                        result = ERROR_FAIL;
                        }
                        targets = targets->next;
                }
                return result;
        }

        RISCV_INFO(r);
        if (r->is_halted == NULL)
                return oldriscv_resume(target, current, address, handle_breakpoints, debug_execution);
        else
                return riscv_openocd_resume(target, current, address, handle_breakpoints, debug_execution);
}

static int riscv_select_current_hart(struct target *target)
{
        RISCV_INFO(r);
        if (riscv_rtos_enabled(target)) {
                if (r->rtos_hartid == -1)
                        r->rtos_hartid = target->rtos->current_threadid - 1;
                return riscv_set_current_hartid(target, r->rtos_hartid);
        } else
                return riscv_set_current_hartid(target, target->coreid);
}

static int riscv_read_memory(struct target *target, target_addr_t address,
                uint32_t size, uint32_t count, uint8_t *buffer)
{
        if (riscv_select_current_hart(target) != ERROR_OK)
                return ERROR_FAIL;
        struct target_type *tt = get_target_type(target);
        return tt->read_memory(target, address, size, count, buffer);
}

static int riscv_write_memory(struct target *target, target_addr_t address,
                uint32_t size, uint32_t count, const uint8_t *buffer)
{
        if (riscv_select_current_hart(target) != ERROR_OK)
                return ERROR_FAIL;
        struct target_type *tt = get_target_type(target);
        return tt->write_memory(target, address, size, count, buffer);
}

static int riscv_get_gdb_reg_list_internal(struct target *target,
                struct reg **reg_list[], int *reg_list_size,
                enum target_register_class reg_class, bool read)
{
        RISCV_INFO(r);
        LOG_DEBUG("rtos_hartid=%d, current_hartid=%d, reg_class=%d, read=%d",
                        r->rtos_hartid, r->current_hartid, reg_class, read);

        if (!target->reg_cache) {
                LOG_ERROR("Target not initialized. Return ERROR_FAIL.");
                return ERROR_FAIL;
        }

        if (riscv_select_current_hart(target) != ERROR_OK)
                return ERROR_FAIL;

        switch (reg_class) {
                case REG_CLASS_GENERAL:
                        *reg_list_size = 33;
                        break;
                case REG_CLASS_ALL:
                        *reg_list_size = target->reg_cache->num_regs;
                        break;
                default:
                        LOG_ERROR("Unsupported reg_class: %d", reg_class);
                        return ERROR_FAIL;
        }

        *reg_list = calloc(*reg_list_size, sizeof(struct reg *));
        if (!*reg_list)
                return ERROR_FAIL;

        for (int i = 0; i < *reg_list_size; i++) {
                assert(!target->reg_cache->reg_list[i].valid ||
                                target->reg_cache->reg_list[i].size > 0);
                (*reg_list)[i] = &target->reg_cache->reg_list[i];
                if (read && !target->reg_cache->reg_list[i].valid) {
                        if (target->reg_cache->reg_list[i].type->get(
                                                &target->reg_cache->reg_list[i]) != ERROR_OK)
                                /* This function is called when first connecting to gdb,
                                 * resulting in an attempt to read all kinds of registers which
                                 * probably will fail. Ignore these failures, and when
                                 * encountered stop reading to save time. */
                                read = false;
                }
        }

        return ERROR_OK;
}

static int riscv_get_gdb_reg_list(struct target *target,
                struct reg **reg_list[], int *reg_list_size,
                enum target_register_class reg_class)
{
        return riscv_get_gdb_reg_list_internal(target, reg_list, reg_list_size,
                        reg_class, true);
}

static int riscv_arch_state(struct target *target)
{
        struct target_type *tt = get_target_type(target);
        return tt->arch_state(target);
}

/* Algorithm must end with a software breakpoint instruction. */
static int riscv_run_algorithm(struct target *target, int num_mem_params,
                struct mem_param *mem_params, int num_reg_params,
                struct reg_param *reg_params, target_addr_t entry_point,
                target_addr_t exit_point, int timeout_ms, void *arch_info)
{
        riscv_info_t *info = (riscv_info_t *) target->arch_info;

        if (num_mem_params > 0) {
                LOG_ERROR("Memory parameters are not supported for RISC-V algorithms.");
                return ERROR_FAIL;
        }

        if (target->state != TARGET_HALTED) {
                LOG_WARNING("target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }

        /* Save registers */
        struct reg *reg_pc = register_get_by_name(target->reg_cache, "pc", 1);
        if (!reg_pc || reg_pc->type->get(reg_pc) != ERROR_OK)
                return ERROR_FAIL;
        uint64_t saved_pc = buf_get_u64(reg_pc->value, 0, reg_pc->size);

        uint64_t saved_regs[32];
        for (int i = 0; i < num_reg_params; i++) {
                if (reg_params[i].direction == PARAM_IN)
                        continue;

                LOG_DEBUG("save %s", reg_params[i].reg_name);
                struct reg *r = register_get_by_name(target->reg_cache, reg_params[i].reg_name, 0);
                if (!r) {
                        LOG_ERROR("Couldn't find register named '%s'", reg_params[i].reg_name);
                        return ERROR_FAIL;
                }

                if (r->size != reg_params[i].size) {
                        LOG_ERROR("Register %s is %d bits instead of %d bits.",
                                        reg_params[i].reg_name, r->size, reg_params[i].size);
                        return ERROR_FAIL;
                }

                if (r->number > GDB_REGNO_XPR31) {
                        LOG_ERROR("Only GPRs can be use as argument registers.");
                        return ERROR_FAIL;
                }

                if (r->type->get(r) != ERROR_OK)
                        return ERROR_FAIL;
                saved_regs[r->number] = buf_get_u64(r->value, 0, r->size);
                if (r->type->set(r, reg_params[i].value) != ERROR_OK)
                        return ERROR_FAIL;
        }


        /* Disable Interrupts before attempting to run the algorithm. */
        uint64_t current_mstatus;
        uint8_t mstatus_bytes[8];

        LOG_DEBUG("Disabling Interrupts");
        struct reg *reg_mstatus = register_get_by_name(target->reg_cache,
                        "mstatus", 1);
        if (!reg_mstatus) {
                LOG_ERROR("Couldn't find mstatus!");
                return ERROR_FAIL;
        }

        reg_mstatus->type->get(reg_mstatus);
        current_mstatus = buf_get_u64(reg_mstatus->value, 0, reg_mstatus->size);
        uint64_t ie_mask = MSTATUS_MIE | MSTATUS_HIE | MSTATUS_SIE | MSTATUS_UIE;
        buf_set_u64(mstatus_bytes, 0, info->xlen[0], set_field(current_mstatus,
                                ie_mask, 0));

        reg_mstatus->type->set(reg_mstatus, mstatus_bytes);

        /* Run algorithm */
        LOG_DEBUG("resume at 0x%" TARGET_PRIxADDR, entry_point);
        if (oldriscv_resume(target, 0, entry_point, 0, 0) != ERROR_OK)
                return ERROR_FAIL;

        int64_t start = timeval_ms();
        while (target->state != TARGET_HALTED) {
                LOG_DEBUG("poll()");
                int64_t now = timeval_ms();
                if (now - start > timeout_ms) {
                        LOG_ERROR("Algorithm timed out after %d ms.", timeout_ms);
                        LOG_ERROR("  now   = 0x%08x", (uint32_t) now);
                        LOG_ERROR("  start = 0x%08x", (uint32_t) start);
                        oldriscv_halt(target);
                        old_or_new_riscv_poll(target);
                        return ERROR_TARGET_TIMEOUT;
                }

                int result = old_or_new_riscv_poll(target);
                if (result != ERROR_OK)
                        return result;
        }

        if (reg_pc->type->get(reg_pc) != ERROR_OK)
                return ERROR_FAIL;
        uint64_t final_pc = buf_get_u64(reg_pc->value, 0, reg_pc->size);
        if (final_pc != exit_point) {
                LOG_ERROR("PC ended up at 0x%" PRIx64 " instead of 0x%"
                                TARGET_PRIxADDR, final_pc, exit_point);
                return ERROR_FAIL;
        }

        /* Restore Interrupts */
        LOG_DEBUG("Restoring Interrupts");
        buf_set_u64(mstatus_bytes, 0, info->xlen[0], current_mstatus);
        reg_mstatus->type->set(reg_mstatus, mstatus_bytes);

        /* Restore registers */
        uint8_t buf[8];
        buf_set_u64(buf, 0, info->xlen[0], saved_pc);
        if (reg_pc->type->set(reg_pc, buf) != ERROR_OK)
                return ERROR_FAIL;

        for (int i = 0; i < num_reg_params; i++) {
                LOG_DEBUG("restore %s", reg_params[i].reg_name);
                struct reg *r = register_get_by_name(target->reg_cache, reg_params[i].reg_name, 0);
                buf_set_u64(buf, 0, info->xlen[0], saved_regs[r->number]);
                if (r->type->set(r, buf) != ERROR_OK)
                        return ERROR_FAIL;
        }

        return ERROR_OK;
}

/* Should run code on the target to perform CRC of
memory. Not yet implemented.
*/

static int riscv_checksum_memory(struct target *target,
                target_addr_t address, uint32_t count,
                uint32_t *checksum)
{
        *checksum = 0xFFFFFFFF;
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
}

/*** OpenOCD Helper Functions ***/

enum riscv_poll_hart {
        RPH_NO_CHANGE,
        RPH_DISCOVERED_HALTED,
        RPH_DISCOVERED_RUNNING,
        RPH_ERROR
};
static enum riscv_poll_hart riscv_poll_hart(struct target *target, int hartid)
{
        RISCV_INFO(r);
        if (riscv_set_current_hartid(target, hartid) != ERROR_OK)
                return RPH_ERROR;

        LOG_DEBUG("polling hart %d, target->state=%d", hartid, target->state);

        /* If OpenOCD thinks we're running but this hart is halted then it's time
         * to raise an event. */
        bool halted = riscv_is_halted(target);
        if (target->state != TARGET_HALTED && halted) {
                LOG_DEBUG("  triggered a halt");
                r->on_halt(target);
                return RPH_DISCOVERED_HALTED;
        } else if (target->state != TARGET_RUNNING && !halted) {
                LOG_DEBUG("  triggered running");
                target->state = TARGET_RUNNING;
                return RPH_DISCOVERED_RUNNING;
        }

        return RPH_NO_CHANGE;
}

int set_debug_reason(struct target *target, int hartid)
{
        switch (riscv_halt_reason(target, hartid)) {
                case RISCV_HALT_BREAKPOINT:
                        target->debug_reason = DBG_REASON_BREAKPOINT;
                        break;
                case RISCV_HALT_TRIGGER:
                        target->debug_reason = DBG_REASON_WATCHPOINT;
                        break;
                case RISCV_HALT_INTERRUPT:
                        target->debug_reason = DBG_REASON_DBGRQ;
                        break;
                case RISCV_HALT_SINGLESTEP:
                        target->debug_reason = DBG_REASON_SINGLESTEP;
                        break;
                case RISCV_HALT_UNKNOWN:
                        target->debug_reason = DBG_REASON_UNDEFINED;
                        break;
                case RISCV_HALT_ERROR:
                        return ERROR_FAIL;
        }
        return ERROR_OK;
}

/*** OpenOCD Interface ***/
int riscv_openocd_poll(struct target *target)
{
        LOG_DEBUG("polling all harts");
        int halted_hart = -1;
        if (riscv_rtos_enabled(target)) {
                /* Check every hart for an event. */
                for (int i = 0; i < riscv_count_harts(target); ++i) {
                        enum riscv_poll_hart out = riscv_poll_hart(target, i);
                        switch (out) {
                        case RPH_NO_CHANGE:
                        case RPH_DISCOVERED_RUNNING:
                                continue;
                        case RPH_DISCOVERED_HALTED:
                                halted_hart = i;
                                break;
                        case RPH_ERROR:
                                return ERROR_FAIL;
                        }
                }
                if (halted_hart == -1) {
                        LOG_DEBUG("  no harts just halted, target->state=%d", target->state);
                        return ERROR_OK;
                }
                LOG_DEBUG("  hart %d halted", halted_hart);

                /* If we're here then at least one hart triggered.  That means
                 * we want to go and halt _every_ hart in the system, as that's
                 * the invariant we hold here.  Some harts might have already
                 * halted (as we're either in single-step mode or they also
                 * triggered a breakpoint), so don't attempt to halt those
                 * harts. */
                for (int i = 0; i < riscv_count_harts(target); ++i)
                        riscv_halt_one_hart(target, i);

        } else if (target->smp) {
                bool halt_discovered = false;
                bool newly_halted[128] = {0};
                unsigned i = 0;
                for (struct target_list *list = target->head; list != NULL;
                                list = list->next, i++) {
                        struct target *t = list->target;
                        riscv_info_t *r = riscv_info(t);
                        assert(i < DIM(newly_halted));
                        enum riscv_poll_hart out = riscv_poll_hart(t, r->current_hartid);
                        switch (out) {
                                case RPH_NO_CHANGE:
                                        break;
                                case RPH_DISCOVERED_RUNNING:
                                        t->state = TARGET_RUNNING;
                                        break;
                                case RPH_DISCOVERED_HALTED:
                                        halt_discovered = true;
                                        newly_halted[i] = true;
                                        t->state = TARGET_HALTED;
                                        if (set_debug_reason(t, r->current_hartid) != ERROR_OK)
                                                return ERROR_FAIL;
                                        break;
                                case RPH_ERROR:
                                        return ERROR_FAIL;
                        }
                }

                if (halt_discovered) {
                        LOG_DEBUG("Halt other targets in this SMP group.");
                        i = 0;
                        for (struct target_list *list = target->head; list != NULL;
                                        list = list->next, i++) {
                                struct target *t = list->target;
                                riscv_info_t *r = riscv_info(t);
                                if (t->state != TARGET_HALTED) {
                                        if (riscv_halt_one_hart(t, r->current_hartid) != ERROR_OK)
                                                return ERROR_FAIL;
                                        t->state = TARGET_HALTED;
                                        if (set_debug_reason(t, r->current_hartid) != ERROR_OK)
                                                return ERROR_FAIL;
                                        newly_halted[i] = true;
                                }
                        }

                        /* Now that we have all our ducks in a row, tell the higher layers
                         * what just happened. */
                        i = 0;
                        for (struct target_list *list = target->head; list != NULL;
                                        list = list->next, i++) {
                                struct target *t = list->target;
                                if (newly_halted[i])
                                        target_call_event_callbacks(t, TARGET_EVENT_HALTED);
                        }
                }
                return ERROR_OK;

        } else {
                enum riscv_poll_hart out = riscv_poll_hart(target,
                                riscv_current_hartid(target));
                if (out == RPH_NO_CHANGE || out == RPH_DISCOVERED_RUNNING)
                        return ERROR_OK;
                else if (out == RPH_ERROR)
                        return ERROR_FAIL;

                halted_hart = riscv_current_hartid(target);
                LOG_DEBUG("  hart %d halted", halted_hart);
        }

        target->state = TARGET_HALTED;
        if (set_debug_reason(target, halted_hart) != ERROR_OK)
                return ERROR_FAIL;

        if (riscv_rtos_enabled(target)) {
                target->rtos->current_threadid = halted_hart + 1;
                target->rtos->current_thread = halted_hart + 1;
                riscv_set_rtos_hartid(target, halted_hart);
        }

        target->state = TARGET_HALTED;

        if (target->debug_reason == DBG_REASON_BREAKPOINT) {
                int retval;
                if (riscv_semihosting(target, &retval) != 0)
                        return retval;
        }

        target_call_event_callbacks(target, TARGET_EVENT_HALTED);
        return ERROR_OK;
}

int riscv_openocd_halt(struct target *target)
{
        RISCV_INFO(r);
        int result;

        LOG_DEBUG("[%d] halting all harts", target->coreid);

        if (target->smp) {
                LOG_DEBUG("Halt other targets in this SMP group.");
                struct target_list *targets = target->head;
                result = ERROR_OK;
                while (targets) {
                        struct target *t = targets->target;
                        targets = targets->next;
                        if (t->state != TARGET_HALTED) {
                                if (riscv_halt_all_harts(t) != ERROR_OK)
                                        result = ERROR_FAIL;
                        }
                }
        } else {
                result = riscv_halt_all_harts(target);
        }

        if (riscv_rtos_enabled(target)) {
                if (r->rtos_hartid != -1) {
                        LOG_DEBUG("halt requested on RTOS hartid %d", r->rtos_hartid);
                        target->rtos->current_threadid = r->rtos_hartid + 1;
                        target->rtos->current_thread = r->rtos_hartid + 1;
                } else
                        LOG_DEBUG("halt requested, but no known RTOS hartid");
        }

        target->state = TARGET_HALTED;
        target->debug_reason = DBG_REASON_DBGRQ;
        target_call_event_callbacks(target, TARGET_EVENT_HALTED);
        return result;
}

int riscv_openocd_resume(
                struct target *target,
                int current,
                target_addr_t address,
                int handle_breakpoints,
                int debug_execution)
{
        LOG_DEBUG("debug_reason=%d", target->debug_reason);

        if (!current)
                riscv_set_register(target, GDB_REGNO_PC, address);

        if (target->debug_reason == DBG_REASON_WATCHPOINT) {
                /* To be able to run off a trigger, disable all the triggers, step, and
                 * then resume as usual. */
                struct watchpoint *watchpoint = target->watchpoints;
                bool trigger_temporarily_cleared[RISCV_MAX_HWBPS] = {0};

                int i = 0;
                int result = ERROR_OK;
                while (watchpoint && result == ERROR_OK) {
                        LOG_DEBUG("watchpoint %d: set=%d", i, watchpoint->set);
                        trigger_temporarily_cleared[i] = watchpoint->set;
                        if (watchpoint->set)
                                result = riscv_remove_watchpoint(target, watchpoint);
                        watchpoint = watchpoint->next;
                        i++;
                }

                if (result == ERROR_OK)
                        result = riscv_step_rtos_hart(target);

                watchpoint = target->watchpoints;
                i = 0;
                while (watchpoint) {
                        LOG_DEBUG("watchpoint %d: cleared=%d", i, trigger_temporarily_cleared[i]);
                        if (trigger_temporarily_cleared[i]) {
                                if (result == ERROR_OK)
                                        result = riscv_add_watchpoint(target, watchpoint);
                                else
                                        riscv_add_watchpoint(target, watchpoint);
                        }
                        watchpoint = watchpoint->next;
                        i++;
                }

                if (result != ERROR_OK)
                        return result;
        }

        int out = riscv_resume_all_harts(target);
        if (out != ERROR_OK) {
                LOG_ERROR("unable to resume all harts");
                return out;
        }

        register_cache_invalidate(target->reg_cache);
        target->state = TARGET_RUNNING;
        target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
        return out;
}

int riscv_openocd_step(
                struct target *target,
                int current,
                target_addr_t address,
                int handle_breakpoints
) {
        LOG_DEBUG("stepping rtos hart");

        if (!current)
                riscv_set_register(target, GDB_REGNO_PC, address);

        int out = riscv_step_rtos_hart(target);
        if (out != ERROR_OK) {
                LOG_ERROR("unable to step rtos hart");
                return out;
        }

        register_cache_invalidate(target->reg_cache);
        target->state = TARGET_RUNNING;
        target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
        target->state = TARGET_HALTED;
        target->debug_reason = DBG_REASON_SINGLESTEP;
        target_call_event_callbacks(target, TARGET_EVENT_HALTED);
        return out;
}

/* Command Handlers */
COMMAND_HANDLER(riscv_set_command_timeout_sec)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
        int timeout = atoi(CMD_ARGV[0]);
        if (timeout <= 0) {
                LOG_ERROR("%s is not a valid integer argument for command.", CMD_ARGV[0]);
                return ERROR_FAIL;
        }

        riscv_command_timeout_sec = timeout;

        return ERROR_OK;
}

COMMAND_HANDLER(riscv_set_reset_timeout_sec)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
        int timeout = atoi(CMD_ARGV[0]);
        if (timeout <= 0) {
                LOG_ERROR("%s is not a valid integer argument for command.", CMD_ARGV[0]);
                return ERROR_FAIL;
        }

        riscv_reset_timeout_sec = timeout;
        return ERROR_OK;
}

COMMAND_HANDLER(riscv_test_compliance) {

        struct target *target = get_current_target(CMD_CTX);

        RISCV_INFO(r);

        if (CMD_ARGC > 0) {
                LOG_ERROR("Command does not take any parameters.");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        if (r->test_compliance) {
                return r->test_compliance(target);
        } else {
                LOG_ERROR("This target does not support this command (may implement an older version of the spec).");
                return ERROR_FAIL;
        }
}

COMMAND_HANDLER(riscv_set_prefer_sba)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
        COMMAND_PARSE_ON_OFF(CMD_ARGV[0], riscv_prefer_sba);
        return ERROR_OK;
}

void parse_error(const char *string, char c, unsigned position)
{
        char buf[position+2];
        for (unsigned i = 0; i < position; i++)
                buf[i] = ' ';
        buf[position] = '^';
        buf[position + 1] = 0;

        LOG_ERROR("Parse error at character %c in:", c);
        LOG_ERROR("%s", string);
        LOG_ERROR("%s", buf);
}

int parse_ranges(range_t **ranges, const char **argv)
{
        for (unsigned pass = 0; pass < 2; pass++) {
                unsigned range = 0;
                unsigned low = 0;
                bool parse_low = true;
                unsigned high = 0;
                for (unsigned i = 0; i == 0 || argv[0][i-1]; i++) {
                        char c = argv[0][i];
                        if (isspace(c)) {
                                /* Ignore whitespace. */
                                continue;
                        }

                        if (parse_low) {
                                if (isdigit(c)) {
                                        low *= 10;
                                        low += c - '0';
                                } else if (c == '-') {
                                        parse_low = false;
                                } else if (c == ',' || c == 0) {
                                        if (pass == 1) {
                                                (*ranges)[range].low = low;
                                                (*ranges)[range].high = low;
                                        }
                                        low = 0;
                                        range++;
                                } else {
                                        parse_error(argv[0], c, i);
                                        return ERROR_COMMAND_SYNTAX_ERROR;
                                }

                        } else {
                                if (isdigit(c)) {
                                        high *= 10;
                                        high += c - '0';
                                } else if (c == ',' || c == 0) {
                                        parse_low = true;
                                        if (pass == 1) {
                                                (*ranges)[range].low = low;
                                                (*ranges)[range].high = high;
                                        }
                                        low = 0;
                                        high = 0;
                                        range++;
                                } else {
                                        parse_error(argv[0], c, i);
                                        return ERROR_COMMAND_SYNTAX_ERROR;
                                }
                        }
                }

                if (pass == 0) {
                        if (*ranges)
                                free(*ranges);
                        *ranges = calloc(range + 2, sizeof(range_t));
                } else {
                        (*ranges)[range].low = 1;
                        (*ranges)[range].high = 0;
                }
        }

        return ERROR_OK;
}

COMMAND_HANDLER(riscv_set_expose_csrs)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        return parse_ranges(&expose_csr, CMD_ARGV);
}

COMMAND_HANDLER(riscv_set_expose_custom)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        return parse_ranges(&expose_custom, CMD_ARGV);
}

COMMAND_HANDLER(riscv_authdata_read)
{
        if (CMD_ARGC != 0) {
                LOG_ERROR("Command takes no parameters");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct target *target = get_current_target(CMD_CTX);
        if (!target) {
                LOG_ERROR("target is NULL!");
                return ERROR_FAIL;
        }

        RISCV_INFO(r);
        if (!r) {
                LOG_ERROR("riscv_info is NULL!");
                return ERROR_FAIL;
        }

        if (r->authdata_read) {
                uint32_t value;
                if (r->authdata_read(target, &value) != ERROR_OK)
                        return ERROR_FAIL;
                command_print(CMD_CTX, "0x%" PRIx32, value);
                return ERROR_OK;
        } else {
                LOG_ERROR("authdata_read is not implemented for this target.");
                return ERROR_FAIL;
        }
}

COMMAND_HANDLER(riscv_authdata_write)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes exactly 1 argument");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct target *target = get_current_target(CMD_CTX);
        RISCV_INFO(r);

        uint32_t value;
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], value);

        if (r->authdata_write) {
                return r->authdata_write(target, value);
        } else {
                LOG_ERROR("authdata_write is not implemented for this target.");
                return ERROR_FAIL;
        }
}

COMMAND_HANDLER(riscv_dmi_read)
{
        if (CMD_ARGC != 1) {
                LOG_ERROR("Command takes 1 parameter");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct target *target = get_current_target(CMD_CTX);
        if (!target) {
                LOG_ERROR("target is NULL!");
                return ERROR_FAIL;
        }

        RISCV_INFO(r);
        if (!r) {
                LOG_ERROR("riscv_info is NULL!");
                return ERROR_FAIL;
        }

        if (r->dmi_read) {
                uint32_t address, value;
                COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], address);
                if (r->dmi_read(target, &value, address) != ERROR_OK)
                        return ERROR_FAIL;
                command_print(CMD_CTX, "0x%" PRIx32, value);
                return ERROR_OK;
        } else {
                LOG_ERROR("dmi_read is not implemented for this target.");
                return ERROR_FAIL;
        }
}


COMMAND_HANDLER(riscv_dmi_write)
{
        if (CMD_ARGC != 2) {
                LOG_ERROR("Command takes exactly 2 arguments");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct target *target = get_current_target(CMD_CTX);
        RISCV_INFO(r);

        uint32_t address, value;
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], address);
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], value);

        if (r->dmi_write) {
                return r->dmi_write(target, address, value);
        } else {
                LOG_ERROR("dmi_write is not implemented for this target.");
                return ERROR_FAIL;
        }
}

COMMAND_HANDLER(riscv_test_sba_config_reg)
{
        if (CMD_ARGC != 4) {
                LOG_ERROR("Command takes exactly 4 arguments");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        struct target *target = get_current_target(CMD_CTX);
        RISCV_INFO(r);

        target_addr_t legal_address;
        uint32_t num_words;
        target_addr_t illegal_address;
        bool run_sbbusyerror_test;

        COMMAND_PARSE_NUMBER(target_addr, CMD_ARGV[0], legal_address);
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], num_words);
        COMMAND_PARSE_NUMBER(target_addr, CMD_ARGV[2], illegal_address);
        COMMAND_PARSE_ON_OFF(CMD_ARGV[3], run_sbbusyerror_test);

        if (r->test_sba_config_reg) {
                return r->test_sba_config_reg(target, legal_address, num_words,
                                illegal_address, run_sbbusyerror_test);
        } else {
                LOG_ERROR("test_sba_config_reg is not implemented for this target.");
                return ERROR_FAIL;
        }
}

COMMAND_HANDLER(riscv_reset_delays)
{
        int wait = 0;

        if (CMD_ARGC > 1) {
                LOG_ERROR("Command takes at most one argument");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        if (CMD_ARGC == 1)
                COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], wait);

        struct target *target = get_current_target(CMD_CTX);
        RISCV_INFO(r);
        r->reset_delays_wait = wait;
        return ERROR_OK;
}

COMMAND_HANDLER(riscv_set_ir)
{
        if (CMD_ARGC != 2) {
                LOG_ERROR("Command takes exactly 2 arguments");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }

        uint32_t value;
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], value);

        if (!strcmp(CMD_ARGV[0], "idcode")) {
                buf_set_u32(ir_idcode, 0, 32, value);
                return ERROR_OK;
        } else if (!strcmp(CMD_ARGV[0], "dtmcs")) {
                buf_set_u32(ir_dtmcontrol, 0, 32, value);
                return ERROR_OK;
        } else if (!strcmp(CMD_ARGV[0], "dmi")) {
                buf_set_u32(ir_dbus, 0, 32, value);
                return ERROR_OK;
        } else {
                return ERROR_FAIL;
        }
}

static const struct command_registration riscv_exec_command_handlers[] = {
        {
                .name = "test_compliance",
                .handler = riscv_test_compliance,
                .mode = COMMAND_EXEC,
                .usage = "riscv test_compliance",
                .help = "Runs a basic compliance test suite against the RISC-V Debug Spec."
        },
        {
                .name = "set_command_timeout_sec",
                .handler = riscv_set_command_timeout_sec,
                .mode = COMMAND_ANY,
                .usage = "riscv set_command_timeout_sec [sec]",
                .help = "Set the wall-clock timeout (in seconds) for individual commands"
        },
        {
                .name = "set_reset_timeout_sec",
                .handler = riscv_set_reset_timeout_sec,
                .mode = COMMAND_ANY,
                .usage = "riscv set_reset_timeout_sec [sec]",
                .help = "Set the wall-clock timeout (in seconds) after reset is deasserted"
        },
        {
                .name = "set_prefer_sba",
                .handler = riscv_set_prefer_sba,
                .mode = COMMAND_ANY,
                .usage = "riscv set_prefer_sba on|off",
                .help = "When on, prefer to use System Bus Access to access memory. "
                        "When off, prefer to use the Program Buffer to access memory."
        },
        {
                .name = "expose_csrs",
                .handler = riscv_set_expose_csrs,
                .mode = COMMAND_ANY,
                .usage = "riscv expose_csrs n0[-m0][,n1[-m1]]...",
                .help = "Configure a list of inclusive ranges for CSRs to expose in "
                                "addition to the standard ones. This must be executed before "
                                "`init`."
        },
        {
                .name = "expose_custom",
                .handler = riscv_set_expose_custom,
                .mode = COMMAND_ANY,
                .usage = "riscv expose_custom n0[-m0][,n1[-m1]]...",
                .help = "Configure a list of inclusive ranges for custom registers to "
                        "expose. custom0 is accessed as abstract register number 0xc000, "
                        "etc. This must be executed before `init`."
        },
        {
                .name = "authdata_read",
                .handler = riscv_authdata_read,
                .mode = COMMAND_ANY,
                .usage = "riscv authdata_read",
                .help = "Return the 32-bit value read from authdata."
        },
        {
                .name = "authdata_write",
                .handler = riscv_authdata_write,
                .mode = COMMAND_ANY,
                .usage = "riscv authdata_write value",
                .help = "Write the 32-bit value to authdata."
        },
        {
                .name = "dmi_read",
                .handler = riscv_dmi_read,
                .mode = COMMAND_ANY,
                .usage = "riscv dmi_read address",
                .help = "Perform a 32-bit DMI read at address, returning the value."
        },
        {
                .name = "dmi_write",
                .handler = riscv_dmi_write,
                .mode = COMMAND_ANY,
                .usage = "riscv dmi_write address value",
                .help = "Perform a 32-bit DMI write of value at address."
        },
        {
                .name = "test_sba_config_reg",
                .handler = riscv_test_sba_config_reg,
                .mode = COMMAND_ANY,
                .usage = "riscv test_sba_config_reg legal_address num_words"
                        "illegal_address run_sbbusyerror_test[on/off]",
                .help = "Perform a series of tests on the SBCS register."
                        "Inputs are a legal, 128-byte aligned address and a number of words to"
                        "read/write starting at that address (i.e., address range [legal address,"
                        "legal_address+word_size*num_words) must be legally readable/writable)"
                        ", an illegal, 128-byte aligned address for error flag/handling cases,"
                        "and whether sbbusyerror test should be run."
        },
        {
                .name = "reset_delays",
                .handler = riscv_reset_delays,
                .mode = COMMAND_ANY,
                .usage = "reset_delays [wait]",
                .help = "OpenOCD learns how many Run-Test/Idle cycles are required "
                        "between scans to avoid encountering the target being busy. This "
                        "command resets those learned values after `wait` scans. It's only "
                        "useful for testing OpenOCD itself."
        },
        {
                .name = "set_ir",
                .handler = riscv_set_ir,
                .mode = COMMAND_ANY,
                .usage = "riscv set_ir_idcode [idcode|dtmcs|dmi] value",
                .help = "Set IR value for specified JTAG register."
        },
        COMMAND_REGISTRATION_DONE
};

extern __COMMAND_HANDLER(handle_common_semihosting_command);
extern __COMMAND_HANDLER(handle_common_semihosting_fileio_command);
extern __COMMAND_HANDLER(handle_common_semihosting_resumable_exit_command);
extern __COMMAND_HANDLER(handle_common_semihosting_cmdline);

/*
 * To be noted that RISC-V targets use the same semihosting commands as
 * ARM targets.
 *
 * The main reason is compatibility with existing tools. For example the
 * Eclipse OpenOCD/SEGGER J-Link/QEMU plug-ins have several widgets to
 * configure semihosting, which generate commands like `arm semihosting
 * enable`.
 * A secondary reason is the fact that the protocol used is exactly the
 * one specified by ARM. If RISC-V will ever define its own semihosting
 * protocol, then a command like `riscv semihosting enable` will make
 * sense, but for now all semihosting commands are prefixed with `arm`.
 */
static const struct command_registration arm_exec_command_handlers[] = {
        {
                "semihosting",
                .handler = handle_common_semihosting_command,
                .mode = COMMAND_EXEC,
                .usage = "['enable'|'disable']",
                .help = "activate support for semihosting operations",
        },
        {
                "semihosting_cmdline",
                .handler = handle_common_semihosting_cmdline,
                .mode = COMMAND_EXEC,
                .usage = "arguments",
                .help = "command line arguments to be passed to program",
        },
        {
                "semihosting_fileio",
                .handler = handle_common_semihosting_fileio_command,
                .mode = COMMAND_EXEC,
                .usage = "['enable'|'disable']",
                .help = "activate support for semihosting fileio operations",
        },
        {
                "semihosting_resexit",
                .handler = handle_common_semihosting_resumable_exit_command,
                .mode = COMMAND_EXEC,
                .usage = "['enable'|'disable']",
                .help = "activate support for semihosting resumable exit",
        },
        COMMAND_REGISTRATION_DONE
};

const struct command_registration riscv_command_handlers[] = {
        {
                .name = "riscv",
                .mode = COMMAND_ANY,
                .help = "RISC-V Command Group",
                .usage = "",
                .chain = riscv_exec_command_handlers
        },
        {
                .name = "arm",
                .mode = COMMAND_ANY,
                .help = "ARM Command Group",
                .usage = "",
                .chain = arm_exec_command_handlers
        },
        COMMAND_REGISTRATION_DONE
};

unsigned riscv_address_bits(struct target *target)
{
        return riscv_xlen(target);
}

struct target_type riscv_target = {
        .name = "riscv",

        .init_target = riscv_init_target,
        .deinit_target = riscv_deinit_target,
        .examine = riscv_examine,

        /* poll current target status */
        .poll = old_or_new_riscv_poll,

        .halt = old_or_new_riscv_halt,
        .resume = old_or_new_riscv_resume,
        .step = old_or_new_riscv_step,

        .assert_reset = riscv_assert_reset,
        .deassert_reset = riscv_deassert_reset,

        .read_memory = riscv_read_memory,
        .write_memory = riscv_write_memory,

        .checksum_memory = riscv_checksum_memory,

        .get_gdb_reg_list = riscv_get_gdb_reg_list,

        .add_breakpoint = riscv_add_breakpoint,
        .remove_breakpoint = riscv_remove_breakpoint,

        .add_watchpoint = riscv_add_watchpoint,
        .remove_watchpoint = riscv_remove_watchpoint,
        .hit_watchpoint = riscv_hit_watchpoint,

        .arch_state = riscv_arch_state,

        .run_algorithm = riscv_run_algorithm,

        .commands = riscv_command_handlers,

        .address_bits = riscv_address_bits
};

/*** RISC-V Interface ***/

void riscv_info_init(struct target *target, riscv_info_t *r)
{
        memset(r, 0, sizeof(*r));
        r->dtm_version = 1;
        r->registers_initialized = false;
        r->current_hartid = target->coreid;

        memset(r->trigger_unique_id, 0xff, sizeof(r->trigger_unique_id));

        for (size_t h = 0; h < RISCV_MAX_HARTS; ++h) {
                r->xlen[h] = -1;

                for (size_t e = 0; e < RISCV_MAX_REGISTERS; ++e)
                        r->valid_saved_registers[h][e] = false;
        }
}

int riscv_halt_all_harts(struct target *target)
{
        for (int i = 0; i < riscv_count_harts(target); ++i) {
                if (!riscv_hart_enabled(target, i))
                        continue;

                riscv_halt_one_hart(target, i);
        }

        riscv_invalidate_register_cache(target);

        return ERROR_OK;
}

int riscv_halt_one_hart(struct target *target, int hartid)
{
        RISCV_INFO(r);
        LOG_DEBUG("halting hart %d", hartid);
        if (riscv_set_current_hartid(target, hartid) != ERROR_OK)
                return ERROR_FAIL;
        if (riscv_is_halted(target)) {
                LOG_DEBUG("  hart %d requested halt, but was already halted", hartid);
                return ERROR_OK;
        }

        int result = r->halt_current_hart(target);
        register_cache_invalidate(target->reg_cache);
        return result;
}

int riscv_resume_all_harts(struct target *target)
{
        for (int i = 0; i < riscv_count_harts(target); ++i) {
                if (!riscv_hart_enabled(target, i))
                        continue;

                riscv_resume_one_hart(target, i);
        }

        riscv_invalidate_register_cache(target);
        return ERROR_OK;
}

int riscv_resume_one_hart(struct target *target, int hartid)
{
        RISCV_INFO(r);
        LOG_DEBUG("resuming hart %d", hartid);
        if (riscv_set_current_hartid(target, hartid) != ERROR_OK)
                return ERROR_FAIL;
        if (!riscv_is_halted(target)) {
                LOG_DEBUG("  hart %d requested resume, but was already resumed", hartid);
                return ERROR_OK;
        }

        r->on_resume(target);
        return r->resume_current_hart(target);
}

int riscv_step_rtos_hart(struct target *target)
{
        RISCV_INFO(r);
        int hartid = r->current_hartid;
        if (riscv_rtos_enabled(target)) {
                hartid = r->rtos_hartid;
                if (hartid == -1) {
                        LOG_DEBUG("GDB has asked me to step \"any\" thread, so I'm stepping hart 0.");
                        hartid = 0;
                }
        }
        if (riscv_set_current_hartid(target, hartid) != ERROR_OK)
                return ERROR_FAIL;
        LOG_DEBUG("stepping hart %d", hartid);

        if (!riscv_is_halted(target)) {
                LOG_ERROR("Hart isn't halted before single step!");
                return ERROR_FAIL;
        }
        riscv_invalidate_register_cache(target);
        r->on_step(target);
        if (r->step_current_hart(target) != ERROR_OK)
                return ERROR_FAIL;
        riscv_invalidate_register_cache(target);
        r->on_halt(target);
        if (!riscv_is_halted(target)) {
                LOG_ERROR("Hart was not halted after single step!");
                return ERROR_FAIL;
        }
        return ERROR_OK;
}

bool riscv_supports_extension(struct target *target, int hartid, char letter)
{
        RISCV_INFO(r);
        unsigned num;
        if (letter >= 'a' && letter <= 'z')
                num = letter - 'a';
        else if (letter >= 'A' && letter <= 'Z')
                num = letter - 'A';
        else
                return false;
        return r->misa[hartid] & (1 << num);
}

int riscv_xlen(const struct target *target)
{
        return riscv_xlen_of_hart(target, riscv_current_hartid(target));
}

int riscv_xlen_of_hart(const struct target *target, int hartid)
{
        RISCV_INFO(r);
        assert(r->xlen[hartid] != -1);
        return r->xlen[hartid];
}

extern struct rtos_type riscv_rtos;
bool riscv_rtos_enabled(const struct target *target)
{
        return false;
}

int riscv_set_current_hartid(struct target *target, int hartid)
{
        RISCV_INFO(r);
        if (!r->select_current_hart)
                return ERROR_OK;

        int previous_hartid = riscv_current_hartid(target);
        r->current_hartid = hartid;
        assert(riscv_hart_enabled(target, hartid));
        LOG_DEBUG("setting hartid to %d, was %d", hartid, previous_hartid);
        if (r->select_current_hart(target) != ERROR_OK)
                return ERROR_FAIL;

        /* This might get called during init, in which case we shouldn't be
         * setting up the register cache. */
        if (target_was_examined(target) && riscv_rtos_enabled(target))
                riscv_invalidate_register_cache(target);

        return ERROR_OK;
}

void riscv_invalidate_register_cache(struct target *target)
{
        RISCV_INFO(r);

        LOG_DEBUG("[%d]", target->coreid);
        register_cache_invalidate(target->reg_cache);
        for (size_t i = 0; i < target->reg_cache->num_regs; ++i) {
                struct reg *reg = &target->reg_cache->reg_list[i];
                reg->valid = false;
        }

        r->registers_initialized = true;
}

int riscv_current_hartid(const struct target *target)
{
        RISCV_INFO(r);
        return r->current_hartid;
}

void riscv_set_all_rtos_harts(struct target *target)
{
        RISCV_INFO(r);
        r->rtos_hartid = -1;
}

void riscv_set_rtos_hartid(struct target *target, int hartid)
{
        LOG_DEBUG("setting RTOS hartid %d", hartid);
        RISCV_INFO(r);
        r->rtos_hartid = hartid;
}

int riscv_count_harts(struct target *target)
{
        if (target == NULL)
                return 1;
        RISCV_INFO(r);
        if (r == NULL)
                return 1;
        return r->hart_count;
}

bool riscv_has_register(struct target *target, int hartid, int regid)
{
        return 1;
}

/**
 * This function is called when the debug user wants to change the value of a
 * register. The new value may be cached, and may not be written until the hart
 * is resumed. */
int riscv_set_register(struct target *target, enum gdb_regno r, riscv_reg_t v)
{
        return riscv_set_register_on_hart(target, riscv_current_hartid(target), r, v);
}

int riscv_set_register_on_hart(struct target *target, int hartid,
                enum gdb_regno regid, uint64_t value)
{
        RISCV_INFO(r);
        LOG_DEBUG("{%d} %s <- %" PRIx64, hartid, gdb_regno_name(regid), value);
        assert(r->set_register);
        return r->set_register(target, hartid, regid, value);
}

int riscv_get_register(struct target *target, riscv_reg_t *value,
                enum gdb_regno r)
{
        return riscv_get_register_on_hart(target, value,
                        riscv_current_hartid(target), r);
}

int riscv_get_register_on_hart(struct target *target, riscv_reg_t *value,
                int hartid, enum gdb_regno regid)
{
        RISCV_INFO(r);

        struct reg *reg = &target->reg_cache->reg_list[regid];

        if (reg && reg->valid && hartid == riscv_current_hartid(target)) {
                *value = buf_get_u64(reg->value, 0, reg->size);
                return ERROR_OK;
        }

        int result = r->get_register(target, value, hartid, regid);

        LOG_DEBUG("{%d} %s: %" PRIx64, hartid, gdb_regno_name(regid), *value);
        return result;
}

bool riscv_is_halted(struct target *target)
{
        RISCV_INFO(r);
        assert(r->is_halted);
        return r->is_halted(target);
}

enum riscv_halt_reason riscv_halt_reason(struct target *target, int hartid)
{
        RISCV_INFO(r);
        if (riscv_set_current_hartid(target, hartid) != ERROR_OK)
                return RISCV_HALT_ERROR;
        if (!riscv_is_halted(target)) {
                LOG_ERROR("Hart is not halted!");
                return RISCV_HALT_UNKNOWN;
        }
        return r->halt_reason(target);
}

size_t riscv_debug_buffer_size(struct target *target)
{
        RISCV_INFO(r);
        return r->debug_buffer_size[riscv_current_hartid(target)];
}

int riscv_write_debug_buffer(struct target *target, int index, riscv_insn_t insn)
{
        RISCV_INFO(r);
        r->write_debug_buffer(target, index, insn);
        return ERROR_OK;
}

riscv_insn_t riscv_read_debug_buffer(struct target *target, int index)
{
        RISCV_INFO(r);
        return r->read_debug_buffer(target, index);
}

int riscv_execute_debug_buffer(struct target *target)
{
        RISCV_INFO(r);
        return r->execute_debug_buffer(target);
}

void riscv_fill_dmi_write_u64(struct target *target, char *buf, int a, uint64_t d)
{
        RISCV_INFO(r);
        r->fill_dmi_write_u64(target, buf, a, d);
}

void riscv_fill_dmi_read_u64(struct target *target, char *buf, int a)
{
        RISCV_INFO(r);
        r->fill_dmi_read_u64(target, buf, a);
}

void riscv_fill_dmi_nop_u64(struct target *target, char *buf)
{
        RISCV_INFO(r);
        r->fill_dmi_nop_u64(target, buf);
}

int riscv_dmi_write_u64_bits(struct target *target)
{
        RISCV_INFO(r);
        return r->dmi_write_u64_bits(target);
}

bool riscv_hart_enabled(struct target *target, int hartid)
{
        /* FIXME: Add a hart mask to the RTOS. */
        if (riscv_rtos_enabled(target))
                return hartid < riscv_count_harts(target);

        return hartid == target->coreid;
}

/**
 * Count triggers, and initialize trigger_count for each hart.
 * trigger_count is initialized even if this function fails to discover
 * something.
 * Disable any hardware triggers that have dmode set. We can't have set them
 * ourselves. Maybe they're left over from some killed debug session.
 * */
int riscv_enumerate_triggers(struct target *target)
{
        RISCV_INFO(r);

        if (r->triggers_enumerated)
                return ERROR_OK;

        r->triggers_enumerated = true;  /* At the very least we tried. */

        for (int hartid = 0; hartid < riscv_count_harts(target); ++hartid) {
                if (!riscv_hart_enabled(target, hartid))
                        continue;

                riscv_reg_t tselect;
                int result = riscv_get_register_on_hart(target, &tselect, hartid,
                                GDB_REGNO_TSELECT);
                if (result != ERROR_OK)
                        return result;

                for (unsigned t = 0; t < RISCV_MAX_TRIGGERS; ++t) {
                        r->trigger_count[hartid] = t;

                        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT, t);
                        uint64_t tselect_rb;
                        result = riscv_get_register_on_hart(target, &tselect_rb, hartid,
                                        GDB_REGNO_TSELECT);
                        if (result != ERROR_OK)
                                return result;
                        /* Mask off the top bit, which is used as tdrmode in old
                         * implementations. */
                        tselect_rb &= ~(1ULL << (riscv_xlen(target)-1));
                        if (tselect_rb != t)
                                break;
                        uint64_t tdata1;
                        result = riscv_get_register_on_hart(target, &tdata1, hartid,
                                        GDB_REGNO_TDATA1);
                        if (result != ERROR_OK)
                                return result;

                        int type = get_field(tdata1, MCONTROL_TYPE(riscv_xlen(target)));
                        switch (type) {
                                case 1:
                                        /* On these older cores we don't support software using
                                         * triggers. */
                                        riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, 0);
                                        break;
                                case 2:
                                        if (tdata1 & MCONTROL_DMODE(riscv_xlen(target)))
                                                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TDATA1, 0);
                                        break;
                        }
                }

                riscv_set_register_on_hart(target, hartid, GDB_REGNO_TSELECT, tselect);

                LOG_INFO("[%d] Found %d triggers", hartid, r->trigger_count[hartid]);
        }

        return ERROR_OK;
}

const char *gdb_regno_name(enum gdb_regno regno)
{
        static char buf[32];

        switch (regno) {
                case GDB_REGNO_ZERO:
                        return "zero";
                case GDB_REGNO_S0:
                        return "s0";
                case GDB_REGNO_S1:
                        return "s1";
                case GDB_REGNO_PC:
                        return "pc";
                case GDB_REGNO_FPR0:
                        return "fpr0";
                case GDB_REGNO_FPR31:
                        return "fpr31";
                case GDB_REGNO_CSR0:
                        return "csr0";
                case GDB_REGNO_TSELECT:
                        return "tselect";
                case GDB_REGNO_TDATA1:
                        return "tdata1";
                case GDB_REGNO_TDATA2:
                        return "tdata2";
                case GDB_REGNO_MISA:
                        return "misa";
                case GDB_REGNO_DPC:
                        return "dpc";
                case GDB_REGNO_DCSR:
                        return "dcsr";
                case GDB_REGNO_DSCRATCH:
                        return "dscratch";
                case GDB_REGNO_MSTATUS:
                        return "mstatus";
                case GDB_REGNO_PRIV:
                        return "priv";
                default:
                        if (regno <= GDB_REGNO_XPR31)
                                sprintf(buf, "x%d", regno - GDB_REGNO_ZERO);
                        else if (regno >= GDB_REGNO_CSR0 && regno <= GDB_REGNO_CSR4095)
                                sprintf(buf, "csr%d", regno - GDB_REGNO_CSR0);
                        else if (regno >= GDB_REGNO_FPR0 && regno <= GDB_REGNO_FPR31)
                                sprintf(buf, "f%d", regno - GDB_REGNO_FPR0);
                        else
                                sprintf(buf, "gdb_regno_%d", regno);
                        return buf;
        }
}

static int register_get(struct reg *reg)
{
        riscv_reg_info_t *reg_info = reg->arch_info;
        struct target *target = reg_info->target;
        uint64_t value;
        int result = riscv_get_register(target, &value, reg->number);
        if (result != ERROR_OK)
                return result;
        buf_set_u64(reg->value, 0, reg->size, value);
        /* CSRs (and possibly other extension) registers may change value at any
         * time. */
        if (reg->number <= GDB_REGNO_XPR31 ||
                        (reg->number >= GDB_REGNO_FPR0 && reg->number <= GDB_REGNO_FPR31) ||
                        reg->number == GDB_REGNO_PC)
                reg->valid = true;
        LOG_DEBUG("[%d]{%d} read 0x%" PRIx64 " from %s (valid=%d)",
                        target->coreid, riscv_current_hartid(target), value, reg->name,
                        reg->valid);
        return ERROR_OK;
}

static int register_set(struct reg *reg, uint8_t *buf)
{
        riscv_reg_info_t *reg_info = reg->arch_info;
        struct target *target = reg_info->target;

        uint64_t value = buf_get_u64(buf, 0, reg->size);

        LOG_DEBUG("[%d]{%d} write 0x%" PRIx64 " to %s (valid=%d)",
                        target->coreid, riscv_current_hartid(target), value, reg->name,
                        reg->valid);
        struct reg *r = &target->reg_cache->reg_list[reg->number];
        /* CSRs (and possibly other extension) registers may change value at any
         * time. */
        if (reg->number <= GDB_REGNO_XPR31 ||
                        (reg->number >= GDB_REGNO_FPR0 && reg->number <= GDB_REGNO_FPR31) ||
                        reg->number == GDB_REGNO_PC)
                r->valid = true;
        memcpy(r->value, buf, (r->size + 7) / 8);

        riscv_set_register(target, reg->number, value);
        return ERROR_OK;
}

static struct reg_arch_type riscv_reg_arch_type = {
        .get = register_get,
        .set = register_set
};

struct csr_info {
        unsigned number;
        const char *name;
};

static int cmp_csr_info(const void *p1, const void *p2)
{
        return (int) (((struct csr_info *)p1)->number) - (int) (((struct csr_info *)p2)->number);
}

int riscv_init_registers(struct target *target)
{
        RISCV_INFO(info);

        if (target->reg_cache) {
                if (target->reg_cache->reg_list)
                        free(target->reg_cache->reg_list);
                free(target->reg_cache);
        }

        target->reg_cache = calloc(1, sizeof(*target->reg_cache));
        target->reg_cache->name = "RISC-V Registers";
        target->reg_cache->num_regs = GDB_REGNO_COUNT;

        if (expose_custom) {
                for (unsigned i = 0; expose_custom[i].low <= expose_custom[i].high; i++) {
                        for (unsigned number = expose_custom[i].low;
                                        number <= expose_custom[i].high;
                                        number++)
                                target->reg_cache->num_regs++;
                }
        }

        LOG_DEBUG("create register cache for %d registers",
                        target->reg_cache->num_regs);

        target->reg_cache->reg_list =
                calloc(target->reg_cache->num_regs, sizeof(struct reg));

        const unsigned int max_reg_name_len = 12;
        if (info->reg_names)
                free(info->reg_names);
        info->reg_names =
                calloc(target->reg_cache->num_regs, max_reg_name_len);
        char *reg_name = info->reg_names;

        static struct reg_feature feature_cpu = {
                .name = "org.gnu.gdb.riscv.cpu"
        };
        static struct reg_feature feature_fpu = {
                .name = "org.gnu.gdb.riscv.fpu"
        };
        static struct reg_feature feature_csr = {
                .name = "org.gnu.gdb.riscv.csr"
        };
        static struct reg_feature feature_virtual = {
                .name = "org.gnu.gdb.riscv.virtual"
        };
        static struct reg_feature feature_custom = {
                .name = "org.gnu.gdb.riscv.custom"
        };

        static struct reg_data_type type_ieee_single = {
                .type = REG_TYPE_IEEE_SINGLE,
                .id = "ieee_single"
        };
        static struct reg_data_type type_ieee_double = {
                .type = REG_TYPE_IEEE_DOUBLE,
                .id = "ieee_double"
        };
        struct csr_info csr_info[] = {
#define DECLARE_CSR(name, number) { number, #name },
#include "encoding.h"
#undef DECLARE_CSR
        };
        /* encoding.h does not contain the registers in sorted order. */
        qsort(csr_info, DIM(csr_info), sizeof(*csr_info), cmp_csr_info);
        unsigned csr_info_index = 0;

        unsigned custom_range_index = 0;
        int custom_within_range = 0;

        riscv_reg_info_t *shared_reg_info = calloc(1, sizeof(riscv_reg_info_t));
        shared_reg_info->target = target;

        /* When gdb requests register N, gdb_get_register_packet() assumes that this
         * is register at index N in reg_list. So if there are certain registers
         * that don't exist, we need to leave holes in the list (or renumber, but
         * it would be nice not to have yet another set of numbers to translate
         * between). */
        for (uint32_t number = 0; number < target->reg_cache->num_regs; number++) {
                struct reg *r = &target->reg_cache->reg_list[number];
                r->dirty = false;
                r->valid = false;
                r->exist = true;
                r->type = &riscv_reg_arch_type;
                r->arch_info = shared_reg_info;
                r->number = number;
                r->size = riscv_xlen(target);
                /* r->size is set in riscv_invalidate_register_cache, maybe because the
                 * target is in theory allowed to change XLEN on us. But I expect a lot
                 * of other things to break in that case as well. */
                if (number <= GDB_REGNO_XPR31) {
                        r->caller_save = true;
                        switch (number) {
                                case GDB_REGNO_ZERO:
                                        r->name = "zero";
                                        break;
                                case GDB_REGNO_RA:
                                        r->name = "ra";
                                        break;
                                case GDB_REGNO_SP:
                                        r->name = "sp";
                                        break;
                                case GDB_REGNO_GP:
                                        r->name = "gp";
                                        break;
                                case GDB_REGNO_TP:
                                        r->name = "tp";
                                        break;
                                case GDB_REGNO_T0:
                                        r->name = "t0";
                                        break;
                                case GDB_REGNO_T1:
                                        r->name = "t1";
                                        break;
                                case GDB_REGNO_T2:
                                        r->name = "t2";
                                        break;
                                case GDB_REGNO_FP:
                                        r->name = "fp";
                                        break;
                                case GDB_REGNO_S1:
                                        r->name = "s1";
                                        break;
                                case GDB_REGNO_A0:
                                        r->name = "a0";
                                        break;
                                case GDB_REGNO_A1:
                                        r->name = "a1";
                                        break;
                                case GDB_REGNO_A2:
                                        r->name = "a2";
                                        break;
                                case GDB_REGNO_A3:
                                        r->name = "a3";
                                        break;
                                case GDB_REGNO_A4:
                                        r->name = "a4";
                                        break;
                                case GDB_REGNO_A5:
                                        r->name = "a5";
                                        break;
                                case GDB_REGNO_A6:
                                        r->name = "a6";
                                        break;
                                case GDB_REGNO_A7:
                                        r->name = "a7";
                                        break;
                                case GDB_REGNO_S2:
                                        r->name = "s2";
                                        break;
                                case GDB_REGNO_S3:
                                        r->name = "s3";
                                        break;
                                case GDB_REGNO_S4:
                                        r->name = "s4";
                                        break;
                                case GDB_REGNO_S5:
                                        r->name = "s5";
                                        break;
                                case GDB_REGNO_S6:
                                        r->name = "s6";
                                        break;
                                case GDB_REGNO_S7:
                                        r->name = "s7";
                                        break;
                                case GDB_REGNO_S8:
                                        r->name = "s8";
                                        break;
                                case GDB_REGNO_S9:
                                        r->name = "s9";
                                        break;
                                case GDB_REGNO_S10:
                                        r->name = "s10";
                                        break;
                                case GDB_REGNO_S11:
                                        r->name = "s11";
                                        break;
                                case GDB_REGNO_T3:
                                        r->name = "t3";
                                        break;
                                case GDB_REGNO_T4:
                                        r->name = "t4";
                                        break;
                                case GDB_REGNO_T5:
                                        r->name = "t5";
                                        break;
                                case GDB_REGNO_T6:
                                        r->name = "t6";
                                        break;
                        }
                        r->group = "general";
                        r->feature = &feature_cpu;
                } else if (number == GDB_REGNO_PC) {
                        r->caller_save = true;
                        sprintf(reg_name, "pc");
                        r->group = "general";
                        r->feature = &feature_cpu;
                } else if (number >= GDB_REGNO_FPR0 && number <= GDB_REGNO_FPR31) {
                        r->caller_save = true;
                        if (riscv_supports_extension(target, riscv_current_hartid(target),
                                                'D')) {
                                r->reg_data_type = &type_ieee_double;
                                r->size = 64;
                        } else if (riscv_supports_extension(target,
                                                riscv_current_hartid(target), 'F')) {
                                r->reg_data_type = &type_ieee_single;
                                r->size = 32;
                        } else {
                                r->exist = false;
                        }
                        switch (number) {
                                case GDB_REGNO_FT0:
                                        r->name = "ft0";
                                        break;
                                case GDB_REGNO_FT1:
                                        r->name = "ft1";
                                        break;
                                case GDB_REGNO_FT2:
                                        r->name = "ft2";
                                        break;
                                case GDB_REGNO_FT3:
                                        r->name = "ft3";
                                        break;
                                case GDB_REGNO_FT4:
                                        r->name = "ft4";
                                        break;
                                case GDB_REGNO_FT5:
                                        r->name = "ft5";
                                        break;
                                case GDB_REGNO_FT6:
                                        r->name = "ft6";
                                        break;
                                case GDB_REGNO_FT7:
                                        r->name = "ft7";
                                        break;
                                case GDB_REGNO_FS0:
                                        r->name = "fs0";
                                        break;
                                case GDB_REGNO_FS1:
                                        r->name = "fs1";
                                        break;
                                case GDB_REGNO_FA0:
                                        r->name = "fa0";
                                        break;
                                case GDB_REGNO_FA1:
                                        r->name = "fa1";
                                        break;
                                case GDB_REGNO_FA2:
                                        r->name = "fa2";
                                        break;
                                case GDB_REGNO_FA3:
                                        r->name = "fa3";
                                        break;
                                case GDB_REGNO_FA4:
                                        r->name = "fa4";
                                        break;
                                case GDB_REGNO_FA5:
                                        r->name = "fa5";
                                        break;
                                case GDB_REGNO_FA6:
                                        r->name = "fa6";
                                        break;
                                case GDB_REGNO_FA7:
                                        r->name = "fa7";
                                        break;
                                case GDB_REGNO_FS2:
                                        r->name = "fs2";
                                        break;
                                case GDB_REGNO_FS3:
                                        r->name = "fs3";
                                        break;
                                case GDB_REGNO_FS4:
                                        r->name = "fs4";
                                        break;
                                case GDB_REGNO_FS5:
                                        r->name = "fs5";
                                        break;
                                case GDB_REGNO_FS6:
                                        r->name = "fs6";
                                        break;
                                case GDB_REGNO_FS7:
                                        r->name = "fs7";
                                        break;
                                case GDB_REGNO_FS8:
                                        r->name = "fs8";
                                        break;
                                case GDB_REGNO_FS9:
                                        r->name = "fs9";
                                        break;
                                case GDB_REGNO_FS10:
                                        r->name = "fs10";
                                        break;
                                case GDB_REGNO_FS11:
                                        r->name = "fs11";
                                        break;
                                case GDB_REGNO_FT8:
                                        r->name = "ft8";
                                        break;
                                case GDB_REGNO_FT9:
                                        r->name = "ft9";
                                        break;
                                case GDB_REGNO_FT10:
                                        r->name = "ft10";
                                        break;
                                case GDB_REGNO_FT11:
                                        r->name = "ft11";
                                        break;
                        }
                        r->group = "float";
                        r->feature = &feature_fpu;
                } else if (number >= GDB_REGNO_CSR0 && number <= GDB_REGNO_CSR4095) {
                        r->group = "csr";
                        r->feature = &feature_csr;
                        unsigned csr_number = number - GDB_REGNO_CSR0;

                        while (csr_info[csr_info_index].number < csr_number &&
                                        csr_info_index < DIM(csr_info) - 1) {
                                csr_info_index++;
                        }
                        if (csr_info[csr_info_index].number == csr_number) {
                                r->name = csr_info[csr_info_index].name;
                        } else {
                                sprintf(reg_name, "csr%d", csr_number);
                                /* Assume unnamed registers don't exist, unless we have some
                                 * configuration that tells us otherwise. That's important
                                 * because eg. Eclipse crashes if a target has too many
                                 * registers, and apparently has no way of only showing a
                                 * subset of registers in any case. */
                                r->exist = false;
                        }

                        switch (csr_number) {
                                case CSR_FFLAGS:
                                case CSR_FRM:
                                case CSR_FCSR:
                                        r->exist = riscv_supports_extension(target,
                                                        riscv_current_hartid(target), 'F');
                                        r->group = "float";
                                        r->feature = &feature_fpu;
                                        break;
                                case CSR_SSTATUS:
                                case CSR_STVEC:
                                case CSR_SIP:
                                case CSR_SIE:
                                case CSR_SCOUNTEREN:
                                case CSR_SSCRATCH:
                                case CSR_SEPC:
                                case CSR_SCAUSE:
                                case CSR_STVAL:
                                case CSR_SATP:
                                        r->exist = riscv_supports_extension(target,
                                                        riscv_current_hartid(target), 'S');
                                        break;
                                case CSR_MEDELEG:
                                case CSR_MIDELEG:
                                        /* "In systems with only M-mode, or with both M-mode and
                                         * U-mode but without U-mode trap support, the medeleg and
                                         * mideleg registers should not exist." */
                                        r->exist = riscv_supports_extension(target, riscv_current_hartid(target), 'S') ||
                                                riscv_supports_extension(target, riscv_current_hartid(target), 'N');
                                        break;

                                case CSR_CYCLEH:
                                case CSR_TIMEH:
                                case CSR_INSTRETH:
                                case CSR_HPMCOUNTER3H:
                                case CSR_HPMCOUNTER4H:
                                case CSR_HPMCOUNTER5H:
                                case CSR_HPMCOUNTER6H:
                                case CSR_HPMCOUNTER7H:
                                case CSR_HPMCOUNTER8H:
                                case CSR_HPMCOUNTER9H:
                                case CSR_HPMCOUNTER10H:
                                case CSR_HPMCOUNTER11H:
                                case CSR_HPMCOUNTER12H:
                                case CSR_HPMCOUNTER13H:
                                case CSR_HPMCOUNTER14H:
                                case CSR_HPMCOUNTER15H:
                                case CSR_HPMCOUNTER16H:
                                case CSR_HPMCOUNTER17H:
                                case CSR_HPMCOUNTER18H:
                                case CSR_HPMCOUNTER19H:
                                case CSR_HPMCOUNTER20H:
                                case CSR_HPMCOUNTER21H:
                                case CSR_HPMCOUNTER22H:
                                case CSR_HPMCOUNTER23H:
                                case CSR_HPMCOUNTER24H:
                                case CSR_HPMCOUNTER25H:
                                case CSR_HPMCOUNTER26H:
                                case CSR_HPMCOUNTER27H:
                                case CSR_HPMCOUNTER28H:
                                case CSR_HPMCOUNTER29H:
                                case CSR_HPMCOUNTER30H:
                                case CSR_HPMCOUNTER31H:
                                case CSR_MCYCLEH:
                                case CSR_MINSTRETH:
                                case CSR_MHPMCOUNTER3H:
                                case CSR_MHPMCOUNTER4H:
                                case CSR_MHPMCOUNTER5H:
                                case CSR_MHPMCOUNTER6H:
                                case CSR_MHPMCOUNTER7H:
                                case CSR_MHPMCOUNTER8H:
                                case CSR_MHPMCOUNTER9H:
                                case CSR_MHPMCOUNTER10H:
                                case CSR_MHPMCOUNTER11H:
                                case CSR_MHPMCOUNTER12H:
                                case CSR_MHPMCOUNTER13H:
                                case CSR_MHPMCOUNTER14H:
                                case CSR_MHPMCOUNTER15H:
                                case CSR_MHPMCOUNTER16H:
                                case CSR_MHPMCOUNTER17H:
                                case CSR_MHPMCOUNTER18H:
                                case CSR_MHPMCOUNTER19H:
                                case CSR_MHPMCOUNTER20H:
                                case CSR_MHPMCOUNTER21H:
                                case CSR_MHPMCOUNTER22H:
                                case CSR_MHPMCOUNTER23H:
                                case CSR_MHPMCOUNTER24H:
                                case CSR_MHPMCOUNTER25H:
                                case CSR_MHPMCOUNTER26H:
                                case CSR_MHPMCOUNTER27H:
                                case CSR_MHPMCOUNTER28H:
                                case CSR_MHPMCOUNTER29H:
                                case CSR_MHPMCOUNTER30H:
                                case CSR_MHPMCOUNTER31H:
                                        r->exist = riscv_xlen(target) == 32;
                                        break;
                        }

                        if (!r->exist && expose_csr) {
                                for (unsigned i = 0; expose_csr[i].low <= expose_csr[i].high; i++) {
                                        if (csr_number >= expose_csr[i].low && csr_number <= expose_csr[i].high) {
                                                LOG_INFO("Exposing additional CSR %d", csr_number);
                                                r->exist = true;
                                                break;
                                        }
                                }
                        }

                } else if (number == GDB_REGNO_PRIV) {
                        sprintf(reg_name, "priv");
                        r->group = "general";
                        r->feature = &feature_virtual;
                        r->size = 8;

                } else {
                        /* Custom registers. */
                        assert(expose_custom);

                        range_t *range = &expose_custom[custom_range_index];
                        assert(range->low <= range->high);
                        unsigned custom_number = range->low + custom_within_range;

                        r->group = "custom";
                        r->feature = &feature_custom;
                        r->arch_info = calloc(1, sizeof(riscv_reg_info_t));
                        assert(r->arch_info);
                        ((riscv_reg_info_t *) r->arch_info)->target = target;
                        ((riscv_reg_info_t *) r->arch_info)->custom_number = custom_number;
                        sprintf(reg_name, "custom%d", custom_number);

                        custom_within_range++;
                        if (custom_within_range > range->high - range->low) {
                                custom_within_range = 0;
                                custom_range_index++;
                        }
                }

                if (reg_name[0])
                        r->name = reg_name;
                reg_name += strlen(reg_name) + 1;
                assert(reg_name < info->reg_names + target->reg_cache->num_regs *
                                max_reg_name_len);
                r->value = &info->reg_cache_values[number];
        }

        return ERROR_OK;
}