Commit 3c79c8b1 authored by David Mosberger-Tang's avatar David Mosberger-Tang Committed by Tony Luck
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[IA64] Schedule fp-clearing insns at least 6 cycles after reading ar.bsp. 



Decreases syscall overhead by approximately 6 cycles.

Signed-off-by: default avatarDavid Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 9ec1a7ad

arch/ia64/kernel/entry.S

+15 −10
Original line number Diff line number Diff line
@@ -705,15 +705,15 @@ ENTRY(ia64_leave_syscall) 
	// start restoring the state saved on the kernel stack (struct pt_regs):

	ld8 r9=[r2],PT(CR_IPSR)-PT(R9)

	ld8 r11=[r3],PT(CR_IIP)-PT(R11)

	mov f6=f0		// clear f6

	nop.i 0

	;;

	invala			// M0|1 invalidate ALAT

	rsm psr.i | psr.ic	// M2 initiate turning off of interrupt and interruption collection

	mov f9=f0		// clear f9

	nop.i 0



	ld8 r29=[r2],16		// load cr.ipsr

	ld8 r28=[r3],16			// load cr.iip

	mov f8=f0		// clear f8

	mov r22=r0		// clear r22

	;;

	ld8 r30=[r2],16		// M0|1 load cr.ifs

	ld8 r25=[r3],16		// M0|1 load ar.unat
@@ -721,15 +721,15 @@ ENTRY(ia64_leave_syscall) 
	;;

	ld8 r26=[r2],PT(B0)-PT(AR_PFS)	// M0|1 load ar.pfs

(pKStk)	mov r22=psr		// M2 read PSR now that interrupts are disabled

	mov f10=f0		// clear f10

(pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13

	;;

	ld8 r21=[r2],PT(AR_RNAT)-PT(B0) // load b0

	ld8 r27=[r3],PT(PR)-PT(AR_RSC)	// load ar.rsc

	mov f11=f0		// clear f11

	mov f6=f0		// clear f6

	;;

	ld8 r24=[r2],PT(AR_FPSR)-PT(AR_RNAT)	// load ar.rnat (may be garbage)

	ld8 r31=[r3],PT(R1)-PT(PR)		// load predicates

(pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13

	mov f7=f0		// clear f7

	;;

	ld8 r20=[r2],PT(R12)-PT(AR_FPSR)	// load ar.fpsr

	ld8.fill r1=[r3],16	// load r1
@@ -737,24 +737,29 @@ ENTRY(ia64_leave_syscall) 
	;;

	srlz.d			// M0  ensure interruption collection is off

	ld8.fill r13=[r3],16

	mov f7=f0		// clear f7

	mov f8=f0		// clear f8

	;;

	ld8.fill r12=[r2]	// restore r12 (sp)

	mov.m ar.ssd=r0		// M2 clear ar.ssd

	mov r22=r0		// clear r22

	mov b6=r18		// I0  restore b6



	nop.m 0

	mov f9=f0		// clear f9

	shr.u r18=r19,16	// I0|1 get byte size of existing "dirty" partition

	;;

	ld8.fill r15=[r3]	// restore r15

(pUStk) st1 [r14]=r17

	addl r3=THIS_CPU(ia64_phys_stacked_size_p8),r0

	;;

(pUStk)	ld4 r17=[r3]		// r17 = cpu_data->phys_stacked_size_p8

	mov.m ar.csd=r0		// M2 clear ar.csd

	mov b6=r18		// I0  restore b6

	mov f10=f0		// clear f10

	;;

	mov r14=r0		// clear r14

	shr.u r18=r19,16	// I0|1 get byte size of existing "dirty" partition

	mov f11=f0		// clear f11

(pKStk) br.cond.dpnt.many skip_rbs_switch





	mov.m ar.ccv=r0		// clear ar.ccv

(pNonSys) br.cond.dpnt.many dont_preserve_current_frame

	br.cond.sptk.many rbs_switch