Commit af1bbc3d authored by Anton Blanchard's avatar Anton Blanchard Committed by Michael Ellerman
Browse files

powerpc: Remove UP only lazy floating point and vector optimisations 



The UP only lazy floating point and vector optimisations were written
back when SMP was not common, and neither glibc nor gcc used vector
instructions. Now SMP is very common, glibc aggressively uses vector
instructions and gcc autovectorises.

We want to add new optimisations that apply to both UP and SMP, but
in preparation for that remove these UP only optimisations.

Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 68bfa962

arch/powerpc/include/asm/processor.h

+0 −6
Original line number Diff line number Diff line
@@ -88,12 +88,6 @@ struct task_struct; 
void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp);

void release_thread(struct task_struct *);



/* Lazy FPU handling on uni-processor */

extern struct task_struct *last_task_used_math;

extern struct task_struct *last_task_used_altivec;

extern struct task_struct *last_task_used_vsx;

extern struct task_struct *last_task_used_spe;



#ifdef CONFIG_PPC32



#if CONFIG_TASK_SIZE > CONFIG_KERNEL_START

arch/powerpc/include/asm/switch_to.h

+0 −8
Original line number Diff line number Diff line
@@ -27,14 +27,6 @@ extern void giveup_spe(struct task_struct *); 
extern void load_up_spe(struct task_struct *);

extern void switch_booke_debug_regs(struct debug_reg *new_debug);



#ifndef CONFIG_SMP

extern void discard_lazy_cpu_state(void);

#else

static inline void discard_lazy_cpu_state(void)

{

}

#endif



#ifdef CONFIG_PPC_FPU

extern void flush_fp_to_thread(struct task_struct *);

extern void giveup_fpu(struct task_struct *);

arch/powerpc/kernel/fpu.S

+0 −35
Original line number Diff line number Diff line
@@ -132,31 +132,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) 
	SYNC

	MTMSRD(r5)			/* enable use of fpu now */

	isync

/*

 * For SMP, we don't do lazy FPU switching because it just gets too

 * horrendously complex, especially when a task switches from one CPU

 * to another.  Instead we call giveup_fpu in switch_to.

 */

#ifndef CONFIG_SMP

	LOAD_REG_ADDRBASE(r3, last_task_used_math)

	toreal(r3)

	PPC_LL	r4,ADDROFF(last_task_used_math)(r3)

	PPC_LCMPI	0,r4,0

	beq	1f

	toreal(r4)

	addi	r4,r4,THREAD		/* want last_task_used_math->thread */

	addi	r10,r4,THREAD_FPSTATE

	SAVE_32FPVSRS(0, R5, R10)

	mffs	fr0

	stfd	fr0,FPSTATE_FPSCR(r10)

	PPC_LL	r5,PT_REGS(r4)

	toreal(r5)

	PPC_LL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

	li	r10,MSR_FP|MSR_FE0|MSR_FE1

	andc	r4,r4,r10		/* disable FP for previous task */

	PPC_STL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

1:

#endif /* CONFIG_SMP */

	/* enable use of FP after return */

#ifdef CONFIG_PPC32

	mfspr	r5,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
@@ -175,11 +150,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) 
	lfd	fr0,FPSTATE_FPSCR(r10)

	MTFSF_L(fr0)

	REST_32FPVSRS(0, R4, R10)

#ifndef CONFIG_SMP

	subi	r4,r5,THREAD

	fromreal(r4)

	PPC_STL	r4,ADDROFF(last_task_used_math)(r3)

#endif /* CONFIG_SMP */

	/* restore registers and return */

	/* we haven't used ctr or xer or lr */

	blr
@@ -226,11 +196,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) 
	andc	r4,r4,r3		/* disable FP for previous task */

	PPC_STL	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

1:

#ifndef CONFIG_SMP

	li	r5,0

	LOAD_REG_ADDRBASE(r4,last_task_used_math)

	PPC_STL	r5,ADDROFF(last_task_used_math)(r4)

#endif /* CONFIG_SMP */

	blr



/*

arch/powerpc/kernel/head_fsl_booke.S

+0 −32
Original line number Diff line number Diff line
@@ -857,29 +857,6 @@ _GLOBAL(load_up_spe) 
	oris	r5,r5,MSR_SPE@h

	mtmsr	r5			/* enable use of SPE now */

	isync

/*

 * For SMP, we don't do lazy SPE switching because it just gets too

 * horrendously complex, especially when a task switches from one CPU

 * to another.  Instead we call giveup_spe in switch_to.

 */

#ifndef CONFIG_SMP

	lis	r3,last_task_used_spe@ha

	lwz	r4,last_task_used_spe@l(r3)

	cmpi	0,r4,0

	beq	1f

	addi	r4,r4,THREAD	/* want THREAD of last_task_used_spe */

	SAVE_32EVRS(0,r10,r4,THREAD_EVR0)

	evxor	evr10, evr10, evr10	/* clear out evr10 */

	evmwumiaa evr10, evr10, evr10	/* evr10 <- ACC = 0 * 0 + ACC */

	li	r5,THREAD_ACC

	evstddx	evr10, r4, r5		/* save off accumulator */

	lwz	r5,PT_REGS(r4)

	lwz	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

	lis	r10,MSR_SPE@h

	andc	r4,r4,r10	/* disable SPE for previous task */

	stw	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

1:

#endif /* !CONFIG_SMP */

	/* enable use of SPE after return */

	oris	r9,r9,MSR_SPE@h

	mfspr	r5,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
@@ -889,10 +866,6 @@ _GLOBAL(load_up_spe) 
	evlddx	evr4,r10,r5

	evmra	evr4,evr4

	REST_32EVRS(0,r10,r5,THREAD_EVR0)

#ifndef CONFIG_SMP

	subi	r4,r5,THREAD

	stw	r4,last_task_used_spe@l(r3)

#endif /* !CONFIG_SMP */

	blr



/*
@@ -1035,11 +1008,6 @@ _GLOBAL(giveup_spe) 
	andc	r4,r4,r3		/* disable SPE for previous task */

	stw	r4,_MSR-STACK_FRAME_OVERHEAD(r5)

1:

#ifndef CONFIG_SMP

	li	r5,0

	lis	r4,last_task_used_spe@ha

	stw	r5,last_task_used_spe@l(r4)

#endif /* !CONFIG_SMP */

	blr

#endif /* CONFIG_SPE */

arch/powerpc/kernel/idle_power7.S

+0 −7
Original line number Diff line number Diff line
@@ -89,13 +89,6 @@ _GLOBAL(power7_powersave_common) 
	std	r0,_LINK(r1)

	std	r0,_NIP(r1)



#ifndef CONFIG_SMP

	/* Make sure FPU, VSX etc... are flushed as we may lose

	 * state when going to nap mode

	 */

	bl	discard_lazy_cpu_state

#endif /* CONFIG_SMP */



	/* Hard disable interrupts */

	mfmsr	r9

	rldicl	r9,r9,48,1

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