From c9ad488289144ae5ef53b012e15895ef1f5e4bb6 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Thu, 6 May 2010 11:45:45 +0300 Subject: x86: Eliminate TS_XSAVE The fpu code currently uses current->thread_info->status & TS_XSAVE as a way to distinguish between XSAVE capable processors and older processors. The decision is not really task specific; instead we use the task status to avoid a global memory reference - the value should be the same across all threads. Eliminate this tie-in into the task structure by using an alternative instruction keyed off the XSAVE cpu feature; this results in shorter and faster code, without introducing a global memory reference. [ hpa: in the future, this probably should use an asm jmp ] Signed-off-by: Avi Kivity Acked-by: Suresh Siddha LKML-Reference: <1273135546-29690-2-git-send-email-avi@redhat.com> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/common.c | 5 +---- arch/x86/kernel/i387.c | 5 +---- arch/x86/kernel/xsave.c | 6 +++--- 3 files changed, 5 insertions(+), 11 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 4868e4a..c1c00d0 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1243,10 +1243,7 @@ void __cpuinit cpu_init(void) /* * Force FPU initialization: */ - if (cpu_has_xsave) - current_thread_info()->status = TS_XSAVE; - else - current_thread_info()->status = 0; + current_thread_info()->status = 0; clear_used_math(); mxcsr_feature_mask_init(); diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 54c31c2..14ca1dc 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -102,10 +102,7 @@ void __cpuinit fpu_init(void) mxcsr_feature_mask_init(); /* clean state in init */ - if (cpu_has_xsave) - current_thread_info()->status = TS_XSAVE; - else - current_thread_info()->status = 0; + current_thread_info()->status = 0; clear_used_math(); } #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 782c3a36..c1b0a11 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -99,7 +99,7 @@ int save_i387_xstate(void __user *buf) if (err) return err; - if (task_thread_info(tsk)->status & TS_XSAVE) + if (use_xsave()) err = xsave_user(buf); else err = fxsave_user(buf); @@ -116,7 +116,7 @@ int save_i387_xstate(void __user *buf) clear_used_math(); /* trigger finit */ - if (task_thread_info(tsk)->status & TS_XSAVE) { + if (use_xsave()) { struct _fpstate __user *fx = buf; struct _xstate __user *x = buf; u64 xstate_bv; @@ -225,7 +225,7 @@ int restore_i387_xstate(void __user *buf) clts(); task_thread_info(current)->status |= TS_USEDFPU; } - if (task_thread_info(tsk)->status & TS_XSAVE) + if (use_xsave()) err = restore_user_xstate(buf); else err = fxrstor_checking((__force struct i387_fxsave_struct *) -- cgit v1.1