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| author | Michael Brown | 2014-05-15 14:04:47 +0200 |
|---|---|---|
| committer | Michael Brown | 2014-05-15 14:04:47 +0200 |
| commit | f747a00c54ccc7b839399c755f1d138a233d368f (patch) | |
| tree | d976619f0b08a3493c15c3625886c0a16ebf58f7 | |
| parent | [build] Merge util/geniso and util/genliso (diff) | |
| download | ipxe-f747a00c54ccc7b839399c755f1d138a233d368f.tar.gz ipxe-f747a00c54ccc7b839399c755f1d138a233d368f.tar.xz ipxe-f747a00c54ccc7b839399c755f1d138a233d368f.zip | |
[lkrnprefix] Make real-mode setup code relocatable
The bzImage boot protocol allows the real-mode code to be loaded at
any segment within base memory. (The fact that both iPXE and recent
versions of Syslinux will load the real-mode code at 1000:0000 is a
coincidence; it is not guaranteed by the specification.)
Fix by making the code relocatable.
Reported-by: Andrew Stuart <andrew@shopcusa.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
| -rw-r--r-- | src/arch/i386/prefix/lkrnprefix.S | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/arch/i386/prefix/lkrnprefix.S b/src/arch/i386/prefix/lkrnprefix.S index de6c6f6bd..259bc6ba5 100644 --- a/src/arch/i386/prefix/lkrnprefix.S +++ b/src/arch/i386/prefix/lkrnprefix.S @@ -1,6 +1,5 @@ FILE_LICENCE ( GPL_ANY ) -#define BZI_RM_SEGMENT 0x1000 #define BZI_LOAD_HIGH_ADDR 0x100000 .text @@ -61,7 +60,7 @@ version: realmode_swtch: .long 0 start_sys: - .word BZI_RM_SEGMENT + .word 0 kernel_version: .word version_string - 0x200 type_of_loader: @@ -114,7 +113,9 @@ version_string: setup: /* Fix up code segment */ - ljmp $BZI_RM_SEGMENT, $1f + pushw %ds + pushw $1f + lret 1: /* Set up stack just below 0x7c00 and clear direction flag */ xorw %ax, %ax |