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Commit 87e522a0 authored by David Mosberger-Tang's avatar David Mosberger-Tang Committed by Tony Luck
Browse files

[IA64] Schedule ia64_leave_syscall() to read ar.bsp earlier 



Reschedule code to read ar.bsp as early as possible.  To enable this,
don't bother clearing some of the registers when we're returning to
kernel stacks.  Also, instead of trying to support the pNonSys case
(which makes no sense), do a bugcheck instead (with break 0).  Finally,
remove a clear of r14 which is a left-over from the previous patch.

Signed-off-by: default avatarDavid Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 060561ff

arch/ia64/kernel/entry.S

+19 −24
Original line number Diff line number Diff line
@@ -694,22 +694,22 @@ ENTRY(ia64_leave_syscall) 
	ld8 r19=[r2],PT(B6)-PT(LOADRS)		// load ar.rsc value for "loadrs"

	nop.i 0

	;;

	ld8 r23=[r3],PT(R11)-PT(AR_BSPSTORE)	// load ar.bspstore (may be garbage)

	mov r16=ar.bsp				// M2  get existing backing store pointer

	ld8 r18=[r2],PT(R9)-PT(B6)		// load b6

(p6)	and r15=TIF_WORK_MASK,r31		// any work other than TIF_SYSCALL_TRACE?

	;;

	mov r16=ar.bsp				// M2  get existing backing store pointer

	ld8 r23=[r3],PT(R11)-PT(AR_BSPSTORE)	// load ar.bspstore (may be garbage)

(p6)	cmp4.ne.unc p6,p0=r15, r0		// any special work pending?

(p6)	br.cond.spnt .work_pending_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)

	nop.i 0

(pNonSys) break 0		//      bug check: we shouldn't be here if pNonSys is TRUE!

	;;

	invala			// M0|1 invalidate ALAT

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

	nop.i 0

	cmp.eq p9,p0=r0,r0	// set p9 to indicate that we should restore cr.ifs



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

	ld8 r28=[r3],16			// load cr.iip
@@ -717,11 +717,11 @@ ENTRY(ia64_leave_syscall) 
	;;

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

	ld8 r25=[r3],16		// M0|1 load ar.unat

	cmp.eq p9,p0=r0,r0	// set p9 to indicate that we should restore cr.ifs

(pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13

	;;

	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

(pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13

	nop 0

	;;

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

	ld8 r27=[r3],PT(PR)-PT(AR_RSC)	// load ar.rsc
@@ -735,40 +735,35 @@ ENTRY(ia64_leave_syscall) 
	ld8.fill r1=[r3],16	// load r1

(pUStk) mov r17=1

	;;

	srlz.d			// M0  ensure interruption collection is off

(pUStk) st1 [r14]=r17

	ld8.fill r13=[r3],16

	mov f8=f0		// clear f8

	;;

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

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

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

	mov b6=r18		// I0  restore b6



	nop.m 0

	addl r17=THIS_CPU(ia64_phys_stacked_size_p8),r0

	mov f9=f0		// clear f9

(pKStk) br.cond.dpnt.many skip_rbs_switch



	srlz.d			// M0  ensure interruption collection is off

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

	cover			// B    add current frame into dirty partition and set cr.ifs

	;;

	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

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

	mov r19=ar.bsp		// M2   get new backing store pointer

	mov f10=f0		// clear f10



	nop.m 0

	movl r14=__kernel_syscall_via_epc	// X

	;;

	nop.m 0

	nop.m 0

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

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

	mov b7=r14		// I0   clear b7 (hint with __kernel_syscall_via_epc)



	mov r14=r0		// clear r14

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

	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

END(ia64_leave_syscall)
@@ -946,10 +941,10 @@ GLOBAL_ENTRY(ia64_leave_kernel) 
	 */

(pNonSys) br.cond.dpnt dont_preserve_current_frame



rbs_switch:

	cover				// add current frame into dirty partition and set cr.ifs

	;;

	mov r19=ar.bsp			// get new backing store pointer

rbs_switch:

	sub r16=r16,r18			// krbs = old bsp - size of dirty partition

	cmp.ne p9,p0=r0,r0		// clear p9 to skip restore of cr.ifs

	;;