add a changelog entry

[debian/elilo] / README.gnu-efi

diff --git a/README.gnu-efi b/README.gnu-efi
index 1653032d641152ea083411012167a84222396744..7007f09c697ff8df033f24fbdf7aab759bc54bde 100644 (file)
--- a/README.gnu-efi
+++ b/README.gnu-efi
@@ -1,5 +1,6 @@
 
                    IMPORTANT Information related to the gnu-efi package
+                               and x86_64 efi support 
                    ----------------------------------------------------
                                        August 2003
 
@@ -12,6 +13,10 @@ As of version elilo-3.0, the gnu-efi package is now split in two different packa
 Note that X.y don't need to match for both packages. However elilo-3.x requires at
 least gnu-efi >= 3.0. When using a version of gcc >3.0 you MUST use at least gnu-efi-3.0a.
 
+Note that EFI support for x86_64 has been added as a patch to gnu-efi-3.0c.
+
+For x86_64, see the important notes under x86_64.
+
 IMPORTANT NOTE FOR IA-32:
 -------------------------
        For IA-32, the Redhat 8.0 toolchain is known to produce
@@ -29,3 +34,32 @@ IMPORTANT NOTE FOR IA-32:
 The gnu-efi  package can be downloaded from:
 
        ftp://ftp.hpl.hp.com/pub/linux-ia64/gnu-efi-X.y.tar.gz
+
+IMPORTANT NOTE FOR x86_64:
+-------------------------
+
+       EFI x86_64 elilo support requires the following libraries:
+
+       1. gnu-efi-3.0c library with x86_64 support.
+
+       2. The toolchain known to produce working x86_64 efi binary are:
+
+               gcc-4.1.1 or above
+               binutils-2.17.50.0.14 with Intel64 EFI support
+
+       Implementation:
+       --------------
+       Calls to EFI services in x86_64 require a wrapper to pass the arguments
+       in the appropriate manner. This is implemented with efi wrapper. 
+       For IA32 and IA64, the wrapper is a macro that merely calls the
+       EFI services directly. The elilo source has been modified to use the
+       efi wrapper implemented in gnu-efi-3.0c library. 
+       elilo for x86_64 and its dependent libraries are built and the final
+       ELF image is converted into PE-COFF image using the objcopy supported
+       by binutils-2.17.50.0.14 or above with Intel64 EFI support.
+
+       On UEFI 2.0 firmware, only Graphics Output Protocol (GOP) is supported. 
+       The x86_64 elilo first queries video information from GOP failing which
+       it queries for text mode support. The video information is passed to
+       Linux kernel via boot parameter. The GOP support requires
+       Linux kernel EFI framebuffer driver (kernel configuration option).