[tip:x86/fpu] x86, fpu: Consolidate inline asm routines for saving/restoring fpu state
From: tip-bot for Suresh Siddha
Date: Tue Sep 18 2012 - 20:00:12 EST
Commit-ID: 0ca5bd0d886578ad0afeceaa83458c0f35cb3c6b
Gitweb: http://git.kernel.org/tip/0ca5bd0d886578ad0afeceaa83458c0f35cb3c6b
Author: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
AuthorDate: Tue, 24 Jul 2012 16:05:28 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 18 Sep 2012 15:51:26 -0700
x86, fpu: Consolidate inline asm routines for saving/restoring fpu state
Consolidate x86, x86_64 inline asm routines saving/restoring fpu state
using config_enabled().
Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1343171129-2747-3-git-send-email-suresh.b.siddha@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/fpu-internal.h | 182 +++++++++++++++--------------------
arch/x86/include/asm/xsave.h | 6 +-
arch/x86/kernel/xsave.c | 4 +-
3 files changed, 80 insertions(+), 112 deletions(-)
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 6f59543..016acb3 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -97,34 +97,24 @@ static inline void sanitize_i387_state(struct task_struct *tsk)
__sanitize_i387_state(tsk);
}
-#ifdef CONFIG_X86_64
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
-{
- int err;
-
- /* See comment in fxsave() below. */
-#ifdef CONFIG_AS_FXSAVEQ
- asm volatile("1: fxrstorq %[fx]\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b, 3b)
- : [err] "=r" (err)
- : [fx] "m" (*fx), "0" (0));
-#else
- asm volatile("1: rex64/fxrstor (%[fx])\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b, 3b)
- : [err] "=r" (err)
- : [fx] "R" (fx), "m" (*fx), "0" (0));
-#endif
- return err;
+#define check_insn(insn, output, input...) \
+({ \
+ int err; \
+ asm volatile("1:" #insn "\n\t" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: movl $-1,%[err]\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : [err] "=r" (err), output \
+ : "0"(0), input); \
+ err; \
+})
+
+static inline int fsave_user(struct i387_fsave_struct __user *fx)
+{
+ return check_insn(fnsave %[fx]; fwait, [fx] "=m" (*fx), "m" (*fx));
}
static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
@@ -140,90 +130,73 @@ static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
if (unlikely(err))
return -EFAULT;
- /* See comment in fxsave() below. */
-#ifdef CONFIG_AS_FXSAVEQ
- asm volatile("1: fxsaveq %[fx]\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b, 3b)
- : [err] "=r" (err), [fx] "=m" (*fx)
- : "0" (0));
-#else
- asm volatile("1: rex64/fxsave (%[fx])\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b, 3b)
- : [err] "=r" (err), "=m" (*fx)
- : [fx] "R" (fx), "0" (0));
-#endif
- if (unlikely(err) &&
- __clear_user(fx, sizeof(struct i387_fxsave_struct)))
- err = -EFAULT;
- /* No need to clear here because the caller clears USED_MATH */
- return err;
+ if (config_enabled(CONFIG_X86_32))
+ return check_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx));
+ else if (config_enabled(CONFIG_AS_FXSAVEQ))
+ return check_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx));
+
+ /* See comment in fpu_fxsave() below. */
+ return check_insn(rex64/fxsave (%[fx]), "=m" (*fx), [fx] "R" (fx));
}
-static inline void fpu_fxsave(struct fpu *fpu)
+static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
{
- /* 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 (config_enabled(CONFIG_X86_32))
+ return check_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+ else if (config_enabled(CONFIG_AS_FXSAVEQ))
+ return check_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
-#ifdef CONFIG_AS_FXSAVEQ
- /* 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));
-#else
- /* 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));
- 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 (%[fx])"
- : "=m" (fpu->state->fxsave)
- : [fx] "R" (&fpu->state->fxsave));
-#endif
+ /* See comment in fpu_fxsave() below. */
+ return check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx),
+ "m" (*fx));
}
-int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- compat_sigset_t *set, struct pt_regs *regs);
-int ia32_setup_frame(int sig, struct k_sigaction *ka,
- compat_sigset_t *set, struct pt_regs *regs);
-
-#else /* CONFIG_X86_32 */
-
-/* perform fxrstor iff the processor has extended states, otherwise frstor */
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+static inline int frstor_checking(struct i387_fsave_struct *fx)
{
- /*
- * The "nop" is needed to make the instructions the same
- * length.
- */
- alternative_input(
- "nop ; frstor %1",
- "fxrstor %1",
- X86_FEATURE_FXSR,
- "m" (*fx));
-
- return 0;
+ return check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
}
static inline void fpu_fxsave(struct fpu *fpu)
{
- asm volatile("fxsave %[fx]"
- : [fx] "=m" (fpu->state->fxsave));
+ if (config_enabled(CONFIG_X86_32))
+ asm volatile( "fxsave %[fx]" : [fx] "=m" (fpu->state->fxsave));
+ else if (config_enabled(CONFIG_AS_FXSAVEQ))
+ asm volatile("fxsaveq %0" : "=m" (fpu->state->fxsave));
+ else {
+ /* 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.
+ *
+ * Using "fxsaveq %0" would be the ideal choice, but is only
+ * supported starting with gas 2.16.
+ *
+ * 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));
+ *
+ * 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 (%[fx])"
+ : "=m" (fpu->state->fxsave)
+ : [fx] "R" (&fpu->state->fxsave));
+ }
}
+#ifdef CONFIG_X86_64
+
+int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+ compat_sigset_t *set, struct pt_regs *regs);
+int ia32_setup_frame(int sig, struct k_sigaction *ka,
+ compat_sigset_t *set, struct pt_regs *regs);
+
+#else /* CONFIG_X86_32 */
#define ia32_setup_frame __setup_frame
#define ia32_setup_rt_frame __setup_rt_frame
@@ -272,17 +245,14 @@ static inline int __save_init_fpu(struct task_struct *tsk)
return fpu_save_init(&tsk->thread.fpu);
}
-static inline int fpu_fxrstor_checking(struct fpu *fpu)
-{
- return fxrstor_checking(&fpu->state->fxsave);
-}
-
static inline int fpu_restore_checking(struct fpu *fpu)
{
if (use_xsave())
- return fpu_xrstor_checking(fpu);
+ return fpu_xrstor_checking(&fpu->state->xsave);
+ else if (use_fxsr())
+ return fxrstor_checking(&fpu->state->fxsave);
else
- return fpu_fxrstor_checking(fpu);
+ return frstor_checking(&fpu->state->fsave);
}
static inline int restore_fpu_checking(struct task_struct *tsk)
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 8a1b6f9..aaac810 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -42,9 +42,8 @@ extern int check_for_xstate(struct i387_fxsave_struct __user *buf,
void __user *fpstate,
struct _fpx_sw_bytes *sw);
-static inline int fpu_xrstor_checking(struct fpu *fpu)
+static inline int fpu_xrstor_checking(struct xsave_struct *fx)
{
- struct xsave_struct *fx = &fpu->state->xsave;
int err;
asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
@@ -84,9 +83,6 @@ static inline int xsave_user(struct xsave_struct __user *buf)
: [err] "=r" (err)
: "D" (buf), "a" (-1), "d" (-1), "0" (0)
: "memory");
- if (unlikely(err) && __clear_user(buf, xstate_size))
- err = -EFAULT;
- /* No need to clear here because the caller clears USED_MATH */
return err;
}
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 9e1a8a7..7a3d4df 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -176,8 +176,10 @@ int save_i387_xstate(void __user *buf)
else
err = fxsave_user(buf);
- if (err)
+ if (unlikely(err)) {
+ __clear_user(buf, xstate_size);
return err;
+ }
user_fpu_end();
} else {
sanitize_i387_state(tsk);
--
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