From 3e7cf5b00dd5b577b4ee9b2a66e40fb670ef210b Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 30 Jun 2011 17:19:32 -0700 Subject: [PATCH] x86-32, fpu: Fix DNA exception during check_fpu() Before check_fpu() is called, we have cr0.TS bit set and hence the floating point code to check the FDIV bug was generating a DNA exception. Use kernel_fpu_begin()/kernel_fpu_end() around the floating point code to avoid this unnecessary device not available exception during boot. Signed-off-by: Suresh Siddha Link: http://lkml.kernel.org/r/1309479572.2665.1372.camel@sbsiddha-MOBL3.sc.intel.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/bugs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 525514cf33c3..46674fbb62ba 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -62,6 +62,8 @@ static void __init check_fpu(void) return; } + kernel_fpu_begin(); + /* * trap_init() enabled FXSR and company _before_ testing for FP * problems here. @@ -80,6 +82,8 @@ static void __init check_fpu(void) : "=m" (*&fdiv_bug) : "m" (*&x), "m" (*&y)); + kernel_fpu_end(); + boot_cpu_data.fdiv_bug = fdiv_bug; if (boot_cpu_data.fdiv_bug) printk(KERN_WARNING "Hmm, FPU with FDIV bug.\n");