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Commit 43d399d2 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
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[S390] cleanup sysc_work and io_work code 



Cleanup the #ifdef mess at io_work in entry[64].S and streamline the
TIF work code of the system call and io exit path.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 94038a99

arch/s390/kernel/entry.S

+28 −47
Original line number Diff line number Diff line
@@ -301,31 +301,29 @@ sysc_restore_trace_psw: 
#endif



#

# recheck if there is more work to do

#

sysc_work_loop:

	tm	__TI_flags+3(%r9),_TIF_WORK_SVC

	bz	BASED(sysc_restore)	# there is no work to do

#

# One of the work bits is on. Find out which one.

# There is work to do, but first we need to check if we return to userspace.

#

sysc_work:

	tm	SP_PSW+1(%r15),0x01	# returning to user ?

	bno	BASED(sysc_restore)



#

# One of the work bits is on. Find out which one.

#

sysc_work_loop:

	tm	__TI_flags+3(%r9),_TIF_MCCK_PENDING

	bo	BASED(sysc_mcck_pending)

	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED

	bo	BASED(sysc_reschedule)

	tm	__TI_flags+3(%r9),_TIF_SIGPENDING

	bnz	BASED(sysc_sigpending)

	bo	BASED(sysc_sigpending)

	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME

	bnz	BASED(sysc_notify_resume)

	bo	BASED(sysc_notify_resume)

	tm	__TI_flags+3(%r9),_TIF_RESTART_SVC

	bo	BASED(sysc_restart)

	tm	__TI_flags+3(%r9),_TIF_SINGLE_STEP

	bo	BASED(sysc_singlestep)

	b	BASED(sysc_restore)

sysc_work_done:

	b	BASED(sysc_return)	# beware of critical section cleanup



#

# _TIF_NEED_RESCHED is set, call schedule
@@ -386,7 +384,7 @@ sysc_singlestep: 
	mvi	SP_SVCNR+1(%r15),0xff

	la	%r2,SP_PTREGS(%r15)	# address of register-save area

	l	%r1,BASED(.Lhandle_per)	# load adr. of per handler

	la	%r14,BASED(sysc_return)	# load adr. of system return

	la	%r14,BASED(sysc_work_loop)	# load adr. of system return

	br	%r1			# branch to do_single_step



#
@@ -636,30 +634,36 @@ io_restore_trace_psw: 
#endif



#

# switch to kernel stack, then check the TIF bits

# There is work todo, find out in which context we have been interrupted:

# 1) if we return to user space we can do all _TIF_WORK_INT work

# 2) if we return to kernel code and preemptive scheduling is enabled check

#    the preemption counter and if it is zero call preempt_schedule_irq

# Before any work can be done, a switch to the kernel stack is required.

#

io_work:

	tm	SP_PSW+1(%r15),0x01	# returning to user ?

#ifndef CONFIG_PREEMPT

	bno	BASED(io_restore)	# no-> skip resched & signal

#else

	bnz	BASED(io_work_user)	# no -> check for preemptive scheduling

	bo	BASED(io_work_user)	# yes -> do resched & signal

#ifdef CONFIG_PREEMPT

	# check for preemptive scheduling

	icm	%r0,15,__TI_precount(%r9)

	bnz	BASED(io_restore)	# preemption disabled

	# switch to kernel stack

	l	%r1,SP_R15(%r15)

	s	%r1,BASED(.Lc_spsize)

	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)

	xc	__SF_BACKCHAIN(4,%r1),__SF_BACKCHAIN(%r1) # clear back chain

	lr	%r15,%r1

io_resume_loop:

	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED

	bno	BASED(io_restore)

	l	%r1,BASED(.Lpreempt_schedule_irq)

	la	%r14,BASED(io_resume_loop)

	br	%r1			# call schedule

	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED

	bor	%r1			# call preempt_schedule_irq

#endif

	b	BASED(io_restore)



#

# Need to do work before returning to userspace, switch to kernel stack

#

io_work_user:

	l	%r1,__LC_KERNEL_STACK

	s	%r1,BASED(.Lc_spsize)
@@ -668,7 +672,7 @@ io_work_user: 
	lr	%r15,%r1

#

# One of the work bits is on. Find out which one.

# Checked are: _TIF_SIGPENDING, _TIF_NEED_RESCHED

# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED

#		and _TIF_MCCK_PENDING

#

io_work_loop:
@@ -677,11 +681,10 @@ io_work_loop: 
	tm	__TI_flags+3(%r9),_TIF_NEED_RESCHED

	bo	BASED(io_reschedule)

	tm	__TI_flags+3(%r9),_TIF_SIGPENDING

	bnz	BASED(io_sigpending)

	bo	BASED(io_sigpending)

	tm	__TI_flags+3(%r9),_TIF_NOTIFY_RESUME

	bnz	BASED(io_notify_resume)

	b	BASED(io_restore)

io_work_done:

	bo	BASED(io_notify_resume)

	b	BASED(io_return)	# beware of critical section cleanup



#

# _TIF_MCCK_PENDING is set, call handler
@@ -701,8 +704,6 @@ io_reschedule: 
	basr	%r14,%r1		# call scheduler

	stnsm	__SF_EMPTY(%r15),0xfc	# disable I/O and ext. interrupts

	TRACE_IRQS_OFF

	tm	__TI_flags+3(%r9),_TIF_WORK_INT

	bz	BASED(io_restore)	# there is no work to do

	b	BASED(io_work_loop)



#
@@ -921,14 +922,10 @@ cleanup_table_sysc_return: 
	.long	sysc_return + 0x80000000, sysc_leave + 0x80000000

cleanup_table_sysc_leave:

	.long	sysc_leave + 0x80000000, sysc_done + 0x80000000

cleanup_table_sysc_work_loop:

	.long	sysc_work_loop + 0x80000000, sysc_work_done + 0x80000000

cleanup_table_io_return:

	.long	io_return + 0x80000000, io_leave + 0x80000000

cleanup_table_io_leave:

	.long	io_leave + 0x80000000, io_done + 0x80000000

cleanup_table_io_work_loop:

	.long	io_work_loop + 0x80000000, io_work_done + 0x80000000



cleanup_critical:

	clc	4(4,%r12),BASED(cleanup_table_system_call)
@@ -945,11 +942,6 @@ cleanup_critical: 
	bl	BASED(0f)

	clc	4(4,%r12),BASED(cleanup_table_sysc_leave+4)

	bl	BASED(cleanup_sysc_leave)

0:

	clc	4(4,%r12),BASED(cleanup_table_sysc_work_loop)

	bl	BASED(0f)

	clc	4(4,%r12),BASED(cleanup_table_sysc_work_loop+4)

	bl	BASED(cleanup_sysc_return)

0:

	clc	4(4,%r12),BASED(cleanup_table_io_return)

	bl	BASED(0f)
@@ -960,11 +952,6 @@ cleanup_critical: 
	bl	BASED(0f)

	clc	4(4,%r12),BASED(cleanup_table_io_leave+4)

	bl	BASED(cleanup_io_leave)

0:

	clc	4(4,%r12),BASED(cleanup_table_io_work_loop)

	bl	BASED(0f)

	clc	4(4,%r12),BASED(cleanup_table_io_work_loop+4)

	bl	BASED(cleanup_io_work_loop)

0:

	br	%r14
@@ -1043,12 +1030,6 @@ cleanup_io_return: 
	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_work_loop:

	mvc	__LC_RETURN_PSW(4),0(%r12)

	mvc	__LC_RETURN_PSW+4(4),BASED(cleanup_table_io_work_loop)

	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_leave:

	clc	4(4,%r12),BASED(cleanup_io_leave_insn)

	be	BASED(2f)

arch/s390/kernel/entry64.S

+36 −72
Original line number Diff line number Diff line
@@ -291,38 +291,36 @@ sysc_restore_trace_psw: 
#endif



#

# recheck if there is more work to do

#

sysc_work_loop:

	tm	__TI_flags+7(%r9),_TIF_WORK_SVC

	jz	sysc_restore	  # there is no work to do

#

# One of the work bits is on. Find out which one.

# There is work to do, but first we need to check if we return to userspace.

#

sysc_work:

	tm	SP_PSW+1(%r15),0x01	# returning to user ?

	jno	sysc_restore



#

# One of the work bits is on. Find out which one.

#

sysc_work_loop:

	tm	__TI_flags+7(%r9),_TIF_MCCK_PENDING

	jo	sysc_mcck_pending

	tm	__TI_flags+7(%r9),_TIF_NEED_RESCHED

	jo	sysc_reschedule

	tm	__TI_flags+7(%r9),_TIF_SIGPENDING

	jnz	sysc_sigpending

	jo	sysc_sigpending

	tm	__TI_flags+7(%r9),_TIF_NOTIFY_RESUME

	jnz	sysc_notify_resume

	jo	sysc_notify_resume

	tm	__TI_flags+7(%r9),_TIF_RESTART_SVC

	jo	sysc_restart

	tm	__TI_flags+7(%r9),_TIF_SINGLE_STEP

	jo	sysc_singlestep

	j	sysc_restore

sysc_work_done:

	j	sysc_return		# beware of critical section cleanup



#

# _TIF_NEED_RESCHED is set, call schedule

#

sysc_reschedule:

	larl	%r14,sysc_work_loop

	jg	schedule	# return point is sysc_return

	jg	schedule		# return point is sysc_work_loop



#

# _TIF_MCCK_PENDING is set, call handler
@@ -369,7 +367,7 @@ sysc_singlestep: 
	ni	__TI_flags+7(%r9),255-_TIF_SINGLE_STEP	# clear TIF_SINGLE_STEP

	xc	SP_SVCNR(2,%r15),SP_SVCNR(%r15)		# clear svc number

	la	%r2,SP_PTREGS(%r15)	# address of register-save area

	larl	%r14,sysc_return	# load adr. of system return

	larl	%r14,sysc_work_loop	# load adr. of system return

	jg	do_single_step		# branch to do_sigtrap



#
@@ -605,37 +603,27 @@ io_restore_trace_psw: 
#endif



#

# There is work todo, we need to check if we return to userspace, then

# check, if we are in SIE, if yes leave it

# There is work todo, find out in which context we have been interrupted:

# 1) if we return to user space we can do all _TIF_WORK_INT work

# 2) if we return to kernel code and kvm is enabled check if we need to

#    modify the psw to leave SIE

# 3) if we return to kernel code and preemptive scheduling is enabled check

#    the preemption counter and if it is zero call preempt_schedule_irq

# Before any work can be done, a switch to the kernel stack is required.

#

io_work:

	tm	SP_PSW+1(%r15),0x01	# returning to user ?

#ifndef CONFIG_PREEMPT

#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)

	jnz	io_work_user		# yes -> no need to check for SIE

	la	%r1, BASED(sie_opcode)	# we return to kernel here

	lg	%r2, SP_PSW+8(%r15)

	clc	0(2,%r1), 0(%r2)	# is current instruction = SIE?

	jne	io_restore		# no-> return to kernel

	lg	%r1, SP_PSW+8(%r15)	# yes-> add 4 bytes to leave SIE

	aghi	%r1, 4

	stg	%r1, SP_PSW+8(%r15)

	j	io_restore		# return to kernel

#else

	jno	io_restore		# no-> skip resched & signal

#endif

#else

	jnz	io_work_user		# yes -> do resched & signal

	jo	io_work_user		# yes -> do resched & signal

#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)

	la	%r1, BASED(sie_opcode)

	lg	%r2, SP_PSW+8(%r15)

	clc	0(2,%r1), 0(%r2)	# is current instruction = SIE?

	lg	%r2,SP_PSW+8(%r15)	# check if current instruction is SIE

	lh	%r1,0(%r2)

	chi	%r1,-19948		# signed 16 bit compare with 0xb214

	jne	0f			# no -> leave PSW alone

	lg	%r1, SP_PSW+8(%r15)	# yes-> add 4 bytes to leave SIE

	aghi	%r1, 4

	stg	%r1, SP_PSW+8(%r15)

	aghi	%r2,4			# yes-> add 4 bytes to leave SIE

	stg	%r2,SP_PSW+8(%r15)

0:

#endif

#ifdef CONFIG_PREEMPT

	# check for preemptive scheduling

	icm	%r0,15,__TI_precount(%r9)

	jnz	io_restore		# preemption is disabled
@@ -646,21 +634,25 @@ io_work: 
	xc	__SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain

	lgr	%r15,%r1

io_resume_loop:

	tm	__TI_flags+7(%r9),_TIF_NEED_RESCHED

	jno	io_restore

	larl	%r14,io_resume_loop

	jg	preempt_schedule_irq

	tm	__TI_flags+7(%r12),_TIF_NEED_RESCHED

	jgo	preempt_schedule_irq

#endif

	j	io_restore



#

# Need to do work before returning to userspace, switch to kernel stack

#

io_work_user:

	lg	%r1,__LC_KERNEL_STACK

	aghi	%r1,-SP_SIZE

	mvc	SP_PTREGS(__PT_SIZE,%r1),SP_PTREGS(%r15)

	xc	__SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) # clear back chain

	lgr	%r15,%r1



#

# One of the work bits is on. Find out which one.

# Checked are: _TIF_SIGPENDING, _TIF_RESTORE_SIGPENDING, _TIF_NEED_RESCHED

# Checked are: _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_NEED_RESCHED

#	       and _TIF_MCCK_PENDING

#

io_work_loop:
@@ -669,16 +661,10 @@ io_work_loop: 
	tm	__TI_flags+7(%r9),_TIF_NEED_RESCHED

	jo	io_reschedule

	tm	__TI_flags+7(%r9),_TIF_SIGPENDING

	jnz	io_sigpending

	jo	io_sigpending

	tm	__TI_flags+7(%r9),_TIF_NOTIFY_RESUME

	jnz	io_notify_resume

	j	io_restore

io_work_done:



#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)

sie_opcode:

	.long 0xb2140000

#endif

	jo	io_notify_resume

	j	io_return		# beware of critical section cleanup



#

# _TIF_MCCK_PENDING is set, call handler
@@ -696,8 +682,6 @@ io_reschedule: 
	brasl	%r14,schedule		# call scheduler

	stnsm	__SF_EMPTY(%r15),0xfc	# disable I/O and ext. interrupts

	TRACE_IRQS_OFF

	tm	__TI_flags+7(%r9),_TIF_WORK_INT

	jz	io_restore		# there is no work to do

	j	io_work_loop



#
@@ -903,14 +887,10 @@ cleanup_table_sysc_return: 
	.quad	sysc_return, sysc_leave

cleanup_table_sysc_leave:

	.quad	sysc_leave, sysc_done

cleanup_table_sysc_work_loop:

	.quad	sysc_work_loop, sysc_work_done

cleanup_table_io_return:

	.quad	io_return, io_leave

cleanup_table_io_leave:

	.quad	io_leave, io_done

cleanup_table_io_work_loop:

	.quad	io_work_loop, io_work_done



cleanup_critical:

	clc	8(8,%r12),BASED(cleanup_table_system_call)
@@ -927,11 +907,6 @@ cleanup_critical: 
	jl	0f

	clc	8(8,%r12),BASED(cleanup_table_sysc_leave+8)

	jl	cleanup_sysc_leave

0:

	clc	8(8,%r12),BASED(cleanup_table_sysc_work_loop)

	jl	0f

	clc	8(8,%r12),BASED(cleanup_table_sysc_work_loop+8)

	jl	cleanup_sysc_return

0:

	clc	8(8,%r12),BASED(cleanup_table_io_return)

	jl	0f
@@ -942,11 +917,6 @@ cleanup_critical: 
	jl	0f

	clc	8(8,%r12),BASED(cleanup_table_io_leave+8)

	jl	cleanup_io_leave

0:

	clc	8(8,%r12),BASED(cleanup_table_io_work_loop)

	jl	0f

	clc	8(8,%r12),BASED(cleanup_table_io_work_loop+8)

	jl	cleanup_io_work_loop

0:

	br	%r14
@@ -1025,12 +995,6 @@ cleanup_io_return: 
	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_work_loop:

	mvc	__LC_RETURN_PSW(8),0(%r12)

	mvc	__LC_RETURN_PSW+8(8),BASED(cleanup_table_io_work_loop)

	la	%r12,__LC_RETURN_PSW

	br	%r14



cleanup_io_leave:

	clc	8(8,%r12),BASED(cleanup_io_leave_insn)

	je	3f