From: Michael K. Johnson Date: Fri, 27 Mar 2009 17:14:41 +0000 (-0400) Subject: x86, setup: mark %esi as clobbered in E820 BIOS call X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=01522df346f846906eaf6ca57148641476209909;p=deliverable%2Flinux.git x86, setup: mark %esi as clobbered in E820 BIOS call Jordan Hargrave diagnosed a BIOS clobbering %esi in the E820 call. That particular BIOS has been fixed, but there is a possibility that this is responsible for other occasional reports of early boot failure, and it does not hurt to add %esi to the clobbers. -stable candidate patch. Cc: Justin Forbes Signed-off-by: Michael K Johnson Signed-off-by: H. Peter Anvin Cc: stable@kernel.org --- diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c index 8c3c25f35578..a99dbbe77a0c 100644 --- a/arch/x86/boot/memory.c +++ b/arch/x86/boot/memory.c @@ -27,13 +27,14 @@ static int detect_memory_e820(void) do { size = sizeof(struct e820entry); - /* Important: %edx is clobbered by some BIOSes, - so it must be either used for the error output + /* Important: %edx and %esi are clobbered by some BIOSes, + so they must be either used for the error output or explicitly marked clobbered. */ asm("int $0x15; setc %0" : "=d" (err), "+b" (next), "=a" (id), "+c" (size), "=m" (*desc) - : "D" (desc), "d" (SMAP), "a" (0xe820)); + : "D" (desc), "d" (SMAP), "a" (0xe820) + : "esi"); /* BIOSes which terminate the chain with CF = 1 as opposed to %ebx = 0 don't always report the SMAP signature on