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| author |   Andreas Schwab <schwab@suse.de> | 2009-01-27 21:45:57 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2009-01-30 23:55:25 +0100 |
| commit | 7fc49f19813030f2e15ad2ccec5cb701f7f4a3ec (patch) | |
| tree | b4e52b975777e18151811019541e24f0a6f2bfc8 | |
| parent | xen: make sysfs files behave as their names suggest (diff) | |
| download | linux-dev-7fc49f19813030f2e15ad2ccec5cb701f7f4a3ec.tar.xz linux-dev-7fc49f19813030f2e15ad2ccec5cb701f7f4a3ec.zip | |
x86 setup: fix asm constraints in vesa_store_edid
Impact: fix potential miscompile (currently believed non-manifest)
As the comment explains, the VBE DDC call can clobber any register.
Tell the compiler about that fact.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/boot/video-vesa.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c index 75115849af33..4a58c8ce3f69 100644 --- a/arch/x86/boot/video-vesa.c +++ b/arch/x86/boot/video-vesa.c @@ -269,9 +269,8 @@ void vesa_store_edid(void) we genuinely have to assume all registers are destroyed here. */ asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es" - : "+a" (ax), "+b" (bx) - : "c" (cx), "D" (di) - : "esi"); + : "+a" (ax), "+b" (bx), "+c" (cx), "+D" (di) + : : "esi", "edx"); if (ax != 0x004f) return; /* No EDID */ @@ -285,9 +284,9 @@ void vesa_store_edid(void) dx = 0; /* EDID block number */ di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */ asm(INT10 - : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info) - : "c" (cx), "D" (di) - : "esi"); + : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info), + "+c" (cx), "+D" (di) + : : "esi"); #endif /* CONFIG_FIRMWARE_EDID */ } |