Commit bf6a4d5b authored by Cyril Bur's avatar Cyril Bur Committed by Michael Ellerman
Browse files

powerpc: Add the ability to save VSX without giving it up 



This patch adds the ability to be able to save the VSX registers to the
thread struct without giving up (disabling the facility) next time the
process returns to userspace.

This patch builds on a previous optimisation for the FPU and VEC registers
in the thread copy path to avoid a possibly pointless reload of VSX state.

Signed-off-by: default avatarCyril Bur <cyrilbur@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 6f515d84

arch/powerpc/include/asm/switch_to.h

+0 −4
Original line number Diff line number Diff line
@@ -56,14 +56,10 @@ static inline void __giveup_altivec(struct task_struct *t) { } 
#ifdef CONFIG_VSX

extern void enable_kernel_vsx(void);

extern void flush_vsx_to_thread(struct task_struct *);

extern void giveup_vsx(struct task_struct *);

extern void __giveup_vsx(struct task_struct *);

static inline void disable_kernel_vsx(void)

{

	msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);

}

#else

static inline void __giveup_vsx(struct task_struct *t) { }

#endif



#ifdef CONFIG_SPE

arch/powerpc/kernel/ppc_ksyms.c

+0 −4
Original line number Diff line number Diff line
@@ -28,10 +28,6 @@ EXPORT_SYMBOL(load_vr_state); 
EXPORT_SYMBOL(store_vr_state);

#endif



#ifdef CONFIG_VSX

EXPORT_SYMBOL_GPL(__giveup_vsx);

#endif



#ifdef CONFIG_EPAPR_PARAVIRT

EXPORT_SYMBOL(epapr_hypercall_start);

#endif

arch/powerpc/kernel/process.c

+30 −12
Original line number Diff line number Diff line
@@ -280,19 +280,31 @@ static inline int restore_altivec(struct task_struct *tsk) { return 0; } 
#endif /* CONFIG_ALTIVEC */



#ifdef CONFIG_VSX

void giveup_vsx(struct task_struct *tsk)

static void __giveup_vsx(struct task_struct *tsk)

{

	check_if_tm_restore_required(tsk);



	msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);

	if (tsk->thread.regs->msr & MSR_FP)

		__giveup_fpu(tsk);

	if (tsk->thread.regs->msr & MSR_VEC)

		__giveup_altivec(tsk);

	tsk->thread.regs->msr &= ~MSR_VSX;

}



static void giveup_vsx(struct task_struct *tsk)

{

	check_if_tm_restore_required(tsk);



	msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);

	__giveup_vsx(tsk);

	msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX);

}

EXPORT_SYMBOL(giveup_vsx);



static void save_vsx(struct task_struct *tsk)

{

	if (tsk->thread.regs->msr & MSR_FP)

		save_fpu(tsk);

	if (tsk->thread.regs->msr & MSR_VEC)

		save_altivec(tsk);

}



void enable_kernel_vsx(void)

{
@@ -335,6 +347,7 @@ static int restore_vsx(struct task_struct *tsk) 
}

#else

static inline int restore_vsx(struct task_struct *tsk) { return 0; }

static inline void save_vsx(struct task_struct *tsk) { }

#endif /* CONFIG_VSX */



#ifdef CONFIG_SPE
@@ -478,14 +491,19 @@ void save_all(struct task_struct *tsk) 


	msr_check_and_set(msr_all_available);



	/*

	 * Saving the way the register space is in hardware, save_vsx boils

	 * down to a save_fpu() and save_altivec()

	 */

	if (usermsr & MSR_VSX) {

		save_vsx(tsk);

	} else {

		if (usermsr & MSR_FP)

			save_fpu(tsk);



		if (usermsr & MSR_VEC)

			save_altivec(tsk);



	if (usermsr & MSR_VSX)

		__giveup_vsx(tsk);

	}



	if (usermsr & MSR_SPE)

		__giveup_spe(tsk);

arch/powerpc/kernel/vector.S

+0 −17
Original line number Diff line number Diff line
@@ -151,23 +151,6 @@ _GLOBAL(load_up_vsx) 
	std	r12,_MSR(r1)

	b	fast_exception_return



/*

 * __giveup_vsx(tsk)

 * Disable VSX for the task given as the argument.

 * Does NOT save vsx registers.

 */

_GLOBAL(__giveup_vsx)

	addi	r3,r3,THREAD		/* want THREAD of task */

	ld	r5,PT_REGS(r3)

	cmpdi	0,r5,0

	beq	1f

	ld	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

	lis	r3,MSR_VSX@h

	andc	r4,r4,r3		/* disable VSX for previous task */

	std	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

1:

	blr



#endif /* CONFIG_VSX */

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