lkml.org 
[lkml]   [2010]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/fpu] x86-32, fpu: Rewrite fpu_save_init()
Commit-ID:  58a992b9cbaf449aeebd3575c3695a9eb5d95b5e
Gitweb: http://git.kernel.org/tip/58a992b9cbaf449aeebd3575c3695a9eb5d95b5e
Author: Brian Gerst <brgerst@gmail.com>
AuthorDate: Fri, 3 Sep 2010 21:17:18 -0400
Committer: H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Thu, 9 Sep 2010 14:17:31 -0700

x86-32, fpu: Rewrite fpu_save_init()

Rewrite fpu_save_init() to prepare for merging with 64-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1283563039-3466-12-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/include/asm/i387.h | 47 ++++++++++++++++++++----------------------
1 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 907967e..b45abef 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -73,6 +73,11 @@ static __always_inline __pure bool use_xsave(void)
return static_cpu_has(X86_FEATURE_XSAVE);
}

+static __always_inline __pure bool use_fxsr(void)
+{
+ return static_cpu_has(X86_FEATURE_FXSR);
+}
+
extern void __sanitize_i387_state(struct task_struct *);

static inline void sanitize_i387_state(struct task_struct *tsk)
@@ -211,6 +216,12 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
return 0;
}

+static inline void fpu_fxsave(struct fpu *fpu)
+{
+ asm volatile("fxsave %[fx]"
+ : [fx] "=m" (fpu->state->fxsave));
+}
+
/* We need a safe address that is cheap to find and that is already
in L1 during context switch. The best choices are unfortunately
different for UP and SMP */
@@ -226,36 +237,24 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
static inline void fpu_save_init(struct fpu *fpu)
{
if (use_xsave()) {
- struct xsave_struct *xstate = &fpu->state->xsave;
- struct i387_fxsave_struct *fx = &fpu->state->fxsave;
-
fpu_xsave(fpu);

/*
* xsave header may indicate the init state of the FP.
*/
- if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
- goto end;
-
- if (unlikely(fx->swd & X87_FSW_ES))
- asm volatile("fnclex");
-
- /*
- * we can do a simple return here or be paranoid :)
- */
- goto clear_state;
+ if (!(fpu->state->xsave.xsave_hdr.xstate_bv & XSTATE_FP))
+ return;
+ } else if (use_fxsr()) {
+ fpu_fxsave(fpu);
+ } else {
+ asm volatile("fsave %[fx]; fwait"
+ : [fx] "=m" (fpu->state->fsave));
+ return;
}

- /* Use more nops than strictly needed in case the compiler
- varies code */
- alternative_input(
- "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
- "fxsave %[fx]\n"
- "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
- X86_FEATURE_FXSR,
- [fx] "m" (fpu->state->fxsave),
- [fsw] "m" (fpu->state->fxsave.swd) : "memory");
-clear_state:
+ if (unlikely(fpu->state->fxsave.swd & X87_FSW_ES))
+ asm volatile("fnclex");
+
/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
is pending. Clear the x87 state here by setting it to fixed
values. safe_address is a random variable that should be in L1 */
@@ -265,8 +264,6 @@ clear_state:
"fildl %[addr]", /* set F?P to defined value */
X86_FEATURE_FXSAVE_LEAK,
[addr] "m" (safe_address));
-end:
- ;
}

#endif /* CONFIG_X86_64 */

\
 
 \ /
  Last update: 2010-09-10 03:57    [from the cache]
©2003-2011 Jasper Spaans