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Date: Fri, 10 Sep 2010 01:48:17 GMT
From: tip-bot for Brian Gerst <brgerst@...il.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
brgerst@...il.com, penberg@...nel.org, suresh.b.siddha@...el.com,
tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/fpu] x86-64, fpu: Simplify constraints for fxsave/fxtstor
Commit-ID: 820241356d6aa9a895fc10def15794a5a5bfcd98
Gitweb: http://git.kernel.org/tip/820241356d6aa9a895fc10def15794a5a5bfcd98
Author: Brian Gerst <brgerst@...il.com>
AuthorDate: Fri, 3 Sep 2010 21:17:14 -0400
Committer: H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Thu, 9 Sep 2010 14:17:06 -0700
x86-64, fpu: Simplify constraints for fxsave/fxtstor
Use the "R" constraint (legacy register) instead of listing all the
possible registers. Clean up the comments as well.
Signed-off-by: Brian Gerst <brgerst@...il.com>
Acked-by: Pekka Enberg <penberg@...nel.org>
Cc: Suresh Siddha <suresh.b.siddha@...el.com>
LKML-Reference: <1283563039-3466-8-git-send-email-brgerst@...il.com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
arch/x86/include/asm/i387.h | 44 ++++++++++++++++--------------------------
1 files changed, 17 insertions(+), 27 deletions(-)
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 8b40a83..768fcb2 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -81,6 +81,7 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
{
int err;
+ /* See comment in fxsave() below. */
asm volatile("1: rex64/fxrstor (%[fx])\n\t"
"2:\n"
".section .fixup,\"ax\"\n"
@@ -89,11 +90,7 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
".previous\n"
_ASM_EXTABLE(1b, 3b)
: [err] "=r" (err)
-#if 0 /* See comment in fxsave() below. */
- : [fx] "r" (fx), "m" (*fx), "0" (0));
-#else
- : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
-#endif
+ : [fx] "R" (fx), "m" (*fx), "0" (0));
return err;
}
@@ -140,6 +137,7 @@ static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
if (unlikely(err))
return -EFAULT;
+ /* See comment in fxsave() below. */
asm volatile("1: rex64/fxsave (%[fx])\n\t"
"2:\n"
".section .fixup,\"ax\"\n"
@@ -148,11 +146,7 @@ static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
".previous\n"
_ASM_EXTABLE(1b, 3b)
: [err] "=r" (err), "=m" (*fx)
-#if 0 /* See comment in fxsave() below. */
- : [fx] "r" (fx), "0" (0));
-#else
- : [fx] "cdaSDb" (fx), "0" (0));
-#endif
+ : [fx] "R" (fx), "0" (0));
if (unlikely(err) &&
__clear_user(fx, sizeof(struct i387_fxsave_struct)))
err = -EFAULT;
@@ -165,26 +159,22 @@ static inline void fpu_fxsave(struct fpu *fpu)
/* Using "rex64; fxsave %0" is broken because, if the memory operand
uses any extended registers for addressing, a second REX prefix
will be generated (to the assembler, rex64 followed by semicolon
- is a separate instruction), and hence the 64-bitness is lost. */
-#if 0
- /* Using "fxsaveq %0" would be the ideal choice, but is only supported
- starting with gas 2.16. */
- __asm__ __volatile__("fxsaveq %0"
- : "=m" (fpu->state->fxsave));
-#elif 0
- /* Using, as a workaround, the properly prefixed form below isn't
+ is a separate instruction), and hence the 64-bitness is lost.
+ Using "fxsaveq %0" would be the ideal choice, but is only supported
+ starting with gas 2.16.
+ asm volatile("fxsaveq %0"
+ : "=m" (fpu->state->fxsave));
+ Using, as a workaround, the properly prefixed form below isn't
accepted by any binutils version so far released, complaining that
the same type of prefix is used twice if an extended register is
- needed for addressing (fix submitted to mainline 2005-11-21). */
- __asm__ __volatile__("rex64/fxsave %0"
- : "=m" (fpu->state->fxsave));
-#else
- /* This, however, we can work around by forcing the compiler to select
+ needed for addressing (fix submitted to mainline 2005-11-21).
+ asm volatile("rex64/fxsave %0"
+ : "=m" (fpu->state->fxsave));
+ This, however, we can work around by forcing the compiler to select
an addressing mode that doesn't require extended registers. */
- __asm__ __volatile__("rex64/fxsave (%1)"
- : "=m" (fpu->state->fxsave)
- : "cdaSDb" (&fpu->state->fxsave));
-#endif
+ asm volatile("rex64/fxsave (%[fx])"
+ : "=m" (fpu->state->fxsave)
+ : [fx] "R" (&fpu->state->fxsave));
}
static inline void fpu_save_init(struct fpu *fpu)
--
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