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x86, fpu: Consolidate inline asm routines for saving/restoring fpu state
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Consolidate x86, x86_64 inline asm routines saving/restoring fpu state
using config_enabled().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1343171129-2747-3-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Suresh Siddha authored and H. Peter Anvin committed Sep 18, 2012
1 parent 050902c commit 0ca5bd0
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Showing 3 changed files with 81 additions and 113 deletions.
184 changes: 77 additions & 107 deletions arch/x86/include/asm/fpu-internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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
Expand Down Expand Up @@ -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)
Expand Down
6 changes: 1 addition & 5 deletions arch/x86/include/asm/xsave.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down Expand Up @@ -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;
}

Expand Down
4 changes: 3 additions & 1 deletion arch/x86/kernel/xsave.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down

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