Commit-ID: c6ab109f7e0eae3bae3bb10f8ddb0df67735c150 Gitweb: http://git.kernel.org/tip/c6ab109f7e0eae3bae3bb10f8ddb0df67735c150 Author: Andy Lutomirski <[email protected]> AuthorDate: Sun, 24 Jan 2016 14:38:09 -0800 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 9 Feb 2016 15:42:56 +0100
x86/fpu: Speed up lazy FPU restores slightly If we have an FPU, there's no need to check CR0 for FPU emulation. Signed-off-by: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Fenghua Yu <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Quentin Casasnovas <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Sai Praneeth Prakhya <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: yu-cheng yu <[email protected]> Link: http://lkml.kernel.org/r/980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 87f80fe..36a9c01 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -752,7 +752,7 @@ do_device_not_available(struct pt_regs *regs, long error_code) RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); #ifdef CONFIG_MATH_EMULATION - if (read_cr0() & X86_CR0_EM) { + if (!boot_cpu_has(X86_FEATURE_FPU) && (read_cr0() & X86_CR0_EM)) { struct math_emu_info info = { }; conditional_sti(regs);
