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Commit 0ca5bd0d authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
Browse files

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: default avatarSuresh 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: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 050902c0

arch/x86/include/asm/fpu-internal.h

+77 −107
Original line number Diff line number Diff line
@@ -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)
@@ -140,61 +130,66 @@ 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. */

	/* See comment in fpu_fxsave() below. */

	return check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx),

			  "m" (*fx));

}



static inline int frstor_checking(struct i387_fsave_struct *fx)

{

	return check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));

}



static inline void fpu_fxsave(struct fpu *fpu)

{

	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));

#endif

	}

}

#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);
@@ -203,28 +198,6 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka, 


#else  /* CONFIG_X86_32 */



/* perform fxrstor iff the processor has extended states, otherwise frstor */

static inline int fxrstor_checking(struct i387_fxsave_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;

}



static inline void fpu_fxsave(struct fpu *fpu)

{

	asm volatile("fxsave %[fx]"

		     : [fx] "=m" (fpu->state->fxsave));

}



#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)

arch/x86/include/asm/xsave.h

+1 −5
Original line number Diff line number Diff line
@@ -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;

}

arch/x86/kernel/xsave.c

+3 −1
Original line number Diff line number Diff line
@@ -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);