From: Andreas Schwab Date: Tue, 27 Jan 2009 20:45:57 +0000 (+0100) Subject: x86 setup: fix asm constraints in vesa_store_edid X-Git-Tag: v5.15~35377^2 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=7fc49f19813030f2e15ad2ccec5cb701f7f4a3ec;p=mirror_ubuntu-kernels.git 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 Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar --- 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 */ }