From 3850427d9afd4c1ee7b51e357e028e3e38bd9aa3 Mon Sep 17 00:00:00 2001 From: Krzysztof Helt Date: Wed, 3 Sep 2008 19:44:55 -0400 Subject: [PATCH] x86: fdiv bug detection fix commit e0d22d03c06c4e2c194d7010bc1e4a972199f156 upstream The fdiv detection code writes s32 integer into the boot_cpu_data.fdiv_bug. However, the boot_cpu_data.fdiv_bug is only char (s8) field so the detection overwrites already set fields for other bugs, e.g. the f00f bug field. Use local s32 variable to receive result. This is a partial fix to Bugzilla #9928 - fixes wrong information about the f00f bug (tested) and probably for coma bug (I have no cpu to test this). Signed-off-by: Krzysztof Helt Cc: Andrew Morton Signed-off-by: Ingo Molnar Cc: Chuck Ebbert Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/bugs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 170d2f5523b2..912a84b89627 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -50,6 +50,8 @@ static double __initdata y = 3145727.0; */ static void __init check_fpu(void) { + s32 fdiv_bug; + if (!boot_cpu_data.hard_math) { #ifndef CONFIG_MATH_EMULATION printk(KERN_EMERG "No coprocessor found and no math emulation present.\n"); @@ -70,8 +72,10 @@ static void __init check_fpu(void) "fistpl %0\n\t" "fwait\n\t" "fninit" - : "=m" (*&boot_cpu_data.fdiv_bug) + : "=m" (*&fdiv_bug) : "m" (*&x), "m" (*&y)); + + boot_cpu_data.fdiv_bug = fdiv_bug; if (boot_cpu_data.fdiv_bug) printk("Hmm, FPU with FDIV bug.\n"); } -- 2.11.4.GIT