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| author | Andreas Schwab <schwab@suse.de> | 2009-01-27 21:45:57 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2009-01-27 14:48:46 -0800 |
| commit | 042cbaf88ab48e11afb725541e3c2cbf5b483680 (patch) | |
| tree | 46bee380febae6ced11562ff1106a1ccda9280aa /arch/x86/boot | |
| parent | 7cb36b6ccdca03bd87e8faca7fd920643dd1aec7 (diff) | |
| download | blackbird-op-linux-042cbaf88ab48e11afb725541e3c2cbf5b483680.tar.gz blackbird-op-linux-042cbaf88ab48e11afb725541e3c2cbf5b483680.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>
Diffstat (limited to 'arch/x86/boot')
| -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 */ } |
