From: Keith Packard <keithp@keithp.com>
Date: Tue, 8 Oct 2013 04:53:53 +0000 (-0700)
Subject: altos/lpc, altos/stm: ARM requires ISB after switching stack pointers
X-Git-Tag: 1.2.9.4~61
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=8f7edcee2db30652ce0b147f282de3396c3786ad;ds=sidebyside

altos/lpc, altos/stm: ARM requires ISB after switching stack pointers

This sticks a barrier in the CPU to prevent using the wrong stack
register past the change.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/lpc/ao_arch_funcs.h b/src/lpc/ao_arch_funcs.h
index 9a3219a2..0891903e 100644
--- a/src/lpc/ao_arch_funcs.h
+++ b/src/lpc/ao_arch_funcs.h
@@ -235,6 +235,7 @@ static inline void ao_arch_start_scheduler(void) {
 	asm("mrs %0,control" : "=&r" (control));
 	control |= (1 << 1);
 	asm("msr control,%0" : : "r" (control));
+	asm("isb");
 }
 
 #endif /* _AO_ARCH_FUNCS_H_ */
diff --git a/src/stm/ao_arch_funcs.h b/src/stm/ao_arch_funcs.h
index 9bb2d7cd..4bcc1023 100644
--- a/src/stm/ao_arch_funcs.h
+++ b/src/stm/ao_arch_funcs.h
@@ -354,6 +354,7 @@ static inline void ao_arch_start_scheduler(void) {
 	asm("mrs %0,control" : "=&r" (control));
 	control |= (1 << 1);
 	asm("msr control,%0" : : "r" (control));
+	asm("isb");
 }
 #endif