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Commit de2a20aa authored by Cyril Bur's avatar Cyril Bur Committed by Michael Ellerman
Browse files

powerpc: Prepare for splitting giveup_{fpu, altivec, vsx} in two 



This prepares for the decoupling of saving {fpu,altivec,vsx} registers and
marking {fpu,altivec,vsx} as being unused by a thread.

Currently giveup_{fpu,altivec,vsx}() does both however optimisations to
task switching can be made if these two operations are decoupled.
save_all() will permit the saving of registers to thread structs and leave
threads MSR with bits enabled.

This patch introduces no functional change.

Signed-off-by: default avatarCyril Bur <cyrilbur@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 70fe3d98

arch/powerpc/include/asm/reg.h

+8 −0
Original line number Diff line number Diff line
@@ -75,6 +75,14 @@ 
#define MSR_HV		0

#endif



/*

 * To be used in shared book E/book S, this avoids needing to worry about

 * book S/book E in shared code

 */

#ifndef MSR_SPE

#define MSR_SPE 	0

#endif



#define MSR_VEC		__MASK(MSR_VEC_LG)	/* Enable AltiVec */

#define MSR_VSX		__MASK(MSR_VSX_LG)	/* Enable VSX */

#define MSR_POW		__MASK(MSR_POW_LG)	/* Enable Power Management */

arch/powerpc/include/asm/switch_to.h

+7 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ static inline void disable_kernel_fp(void) 
	msr_check_and_clear(MSR_FP);

}

#else

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

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

#endif
@@ -46,6 +47,8 @@ static inline void disable_kernel_altivec(void) 
{

	msr_check_and_clear(MSR_VEC);

}

#else

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

#endif



#ifdef CONFIG_VSX
@@ -57,6 +60,8 @@ 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
@@ -68,6 +73,8 @@ static inline void disable_kernel_spe(void) 
{

	msr_check_and_clear(MSR_SPE);

}

#else

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

#endif



static inline void clear_task_ebb(struct task_struct *t)

arch/powerpc/kernel/process.c

+30 −1
Original line number Diff line number Diff line
@@ -444,12 +444,41 @@ void restore_math(struct pt_regs *regs) 
	regs->msr = msr;

}



void save_all(struct task_struct *tsk)

{

	unsigned long usermsr;



	if (!tsk->thread.regs)

		return;



	usermsr = tsk->thread.regs->msr;



	if ((usermsr & msr_all_available) == 0)

		return;



	msr_check_and_set(msr_all_available);



	if (usermsr & MSR_FP)

		__giveup_fpu(tsk);



	if (usermsr & MSR_VEC)

		__giveup_altivec(tsk);



	if (usermsr & MSR_VSX)

		__giveup_vsx(tsk);



	if (usermsr & MSR_SPE)

		__giveup_spe(tsk);



	msr_check_and_clear(msr_all_available);

}



void flush_all_to_thread(struct task_struct *tsk)

{

	if (tsk->thread.regs) {

		preempt_disable();

		BUG_ON(tsk != current);

		giveup_all(tsk);

		save_all(tsk);



#ifdef CONFIG_SPE

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