linux-kernel - Fix asm constraints in vesa_store

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 27 Jan 2009 21:45:57 +0100
From:	Andreas Schwab <schwab@...e.de>
To:	hpa@...or.com
Cc:	linux-kernel@...r.kernel.org
Subject: Fix asm constraints in vesa_store_edid

As the comment explains, the VBE DDC call can clobber any register.
Tell the compiler about that fact.

Signed-off-by: Andreas Schwab <schwab@...e.de>

---
 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 7511584..4a58c8c 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 */
 }
 

-- 
Andreas Schwab, SuSE Labs, schwab@...e.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/