Commit d0fc4107 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/kvm: integrate HANDLE_SIE_INTERCEPT into cleanup_critical 



Currently there are two mechanisms to deal with cleanup work due to
interrupts. The HANDLE_SIE_INTERCEPT macro is used to undo the changes
required to enter SIE in sie64a. If the SIE instruction causes a program
check, or an asynchronous interrupt is received the HANDLE_SIE_INTERCEPT
code forwards the program execution to sie_exit.

All the other critical sections in entry.S are handled by the code in
cleanup_critical that is called by the SWITCH_ASYNC macro.

Move the sie64a function to the beginning of the critical section and
add the code from HANDLE_SIE_INTERCEPT to cleanup_critical. Add a special
case for the sie64a cleanup to the program check handler.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent dcd2a9aa

arch/s390/kernel/entry.S

+123 −118
Original line number Diff line number Diff line
@@ -75,31 +75,6 @@ _PIF_WORK = (_PIF_PER_TRAP) 
#endif

	.endm



	.macro LPP newpp

#if IS_ENABLED(CONFIG_KVM)

	tm	__LC_MACHINE_FLAGS+6,0x20	# MACHINE_FLAG_LPP

	jz	.+8

	.insn	s,0xb2800000,\newpp

#endif

	.endm



	.macro	HANDLE_SIE_INTERCEPT scratch,reason

#if IS_ENABLED(CONFIG_KVM)

	tmhh	%r8,0x0001		# interrupting from user ?

	jnz	.+62

	lgr	\scratch,%r9

	slg	\scratch,BASED(.Lsie_critical)

	clg	\scratch,BASED(.Lsie_critical_length)

	jhe	.+42

	lg	%r14,__SF_EMPTY(%r15)		# get control block pointer

	LPP	__SF_EMPTY+16(%r15)		# set host id

	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE

	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce

	larl	%r9,sie_exit			# skip forward to sie_exit

	mvi	__SF_EMPTY+31(%r15),\reason	# set exit reason

#endif

	.endm



	.macro	CHECK_STACK stacksize,savearea

#ifdef CONFIG_CHECK_STACK

	tml	%r15,\stacksize - CONFIG_STACK_GUARD
@@ -192,6 +167,70 @@ ENTRY(__switch_to) 
	br	%r14



.L__critical_start:



#if IS_ENABLED(CONFIG_KVM)

/*

 * sie64a calling convention:

 * %r2 pointer to sie control block

 * %r3 guest register save area

 */

ENTRY(sie64a)

	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers

	stg	%r2,__SF_EMPTY(%r15)		# save control block pointer

	stg	%r3,__SF_EMPTY+8(%r15)		# save guest register save area

	xc	__SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason

	tm	__LC_CPU_FLAGS+7,_CIF_FPU	# load guest fp/vx registers ?

	jno	.Lsie_load_guest_gprs

	lg	%r12,__LC_THREAD_INFO		# load fp/vx regs save area

	brasl	%r14,load_fpu_regs		# load guest fp/vx regs

.Lsie_load_guest_gprs:

	lmg	%r0,%r13,0(%r3)			# load guest gprs 0-13

	lg	%r14,__LC_GMAP			# get gmap pointer

	ltgr	%r14,%r14

	jz	.Lsie_gmap

	lctlg	%c1,%c1,__GMAP_ASCE(%r14)	# load primary asce

.Lsie_gmap:

	lg	%r14,__SF_EMPTY(%r15)		# get control block pointer

	oi	__SIE_PROG0C+3(%r14),1		# we are going into SIE now

	tm	__SIE_PROG20+3(%r14),3		# last exit...

	jnz	.Lsie_skip

	tm	__LC_CPU_FLAGS+7,_CIF_FPU

	jo	.Lsie_skip			# exit if fp/vx regs changed

	tm	__LC_MACHINE_FLAGS+6,0x20	# MACHINE_FLAG_LPP

	jz	.Lsie_enter

	.insn	s,0xb2800000,__SF_EMPTY(%r15)	# set guest id

.Lsie_enter:

	sie	0(%r14)

	tm	__LC_MACHINE_FLAGS+6,0x20	# MACHINE_FLAG_LPP

	jz	.Lsie_skip

	.insn	s,0xb2800000,__SF_EMPTY+16(%r15)# set host id

.Lsie_skip:

	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE

	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce

.Lsie_done:

# some program checks are suppressing. C code (e.g. do_protection_exception)

# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other

# instructions between sie64a and .Lsie_done should not cause program

# interrupts. So lets use a nop (47 00 00 00) as a landing pad.

# See also .Lcleanup_sie

.Lrewind_pad:

	nop	0

	.globl sie_exit

sie_exit:

	lg	%r14,__SF_EMPTY+8(%r15)		# load guest register save area

	stmg	%r0,%r13,0(%r14)		# save guest gprs 0-13

	lmg	%r6,%r14,__SF_GPRS(%r15)	# restore kernel registers

	lg	%r2,__SF_EMPTY+24(%r15)		# return exit reason code

	br	%r14

.Lsie_fault:

	lghi	%r14,-EFAULT

	stg	%r14,__SF_EMPTY+24(%r15)	# set exit reason code

	j	sie_exit



	EX_TABLE(.Lrewind_pad,.Lsie_fault)

	EX_TABLE(sie_exit,.Lsie_fault)

#endif



/*

 * SVC interrupt handler routine. System calls are synchronous events and

 * are executed with interrupts enabled.
@@ -411,26 +450,33 @@ ENTRY(pgm_check_handler) 
	lg	%r12,__LC_THREAD_INFO

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_PGM_OLD_PSW

	HANDLE_SIE_INTERCEPT %r14,1

	tmhh	%r8,0x0001		# test problem state bit

	jnz	1f			# -> fault in user space

	tmhh	%r8,0x4000		# PER bit set in old PSW ?

	jnz	0f			# -> enabled, can't be a double fault

	jnz	2f			# -> fault in user space

#if IS_ENABLED(CONFIG_KVM)

	# cleanup critical section for sie64a

	lgr	%r14,%r9

	slg	%r14,BASED(.Lsie_critical_start)

	clg	%r14,BASED(.Lsie_critical_length)

	jhe	0f

	brasl	%r14,.Lcleanup_sie

#endif

0:	tmhh	%r8,0x4000		# PER bit set in old PSW ?

	jnz	1f			# -> enabled, can't be a double fault

	tm	__LC_PGM_ILC+3,0x80	# check for per exception

	jnz	.Lpgm_svcper		# -> single stepped svc

0:	CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC

1:	CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC

	aghi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)

	j	2f

1:	UPDATE_VTIME %r14,__LC_SYNC_ENTER_TIMER

	j	3f

2:	UPDATE_VTIME %r14,__LC_SYNC_ENTER_TIMER

	LAST_BREAK %r14

	lg	%r15,__LC_KERNEL_STACK

	lg	%r14,__TI_task(%r12)

	aghi	%r14,__TASK_thread	# pointer to thread_struct

	lghi	%r13,__LC_PGM_TDB

	tm	__LC_PGM_ILC+2,0x02	# check for transaction abort

	jz	2f

	jz	3f

	mvc	__THREAD_trap_tdb(256,%r14),0(%r13)

2:	la	%r11,STACK_FRAME_OVERHEAD(%r15)

3:	la	%r11,STACK_FRAME_OVERHEAD(%r15)

	stmg	%r0,%r7,__PT_R0(%r11)

	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_SYNC

	stmg	%r8,%r9,__PT_PSW(%r11)
@@ -439,14 +485,14 @@ ENTRY(pgm_check_handler) 
	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)

	stg	%r10,__PT_ARGS(%r11)

	tm	__LC_PGM_ILC+3,0x80	# check for per exception

	jz	0f

	jz	4f

	tmhh	%r8,0x0001		# kernel per event ?

	jz	.Lpgm_kprobe

	oi	__PT_FLAGS+7(%r11),_PIF_PER_TRAP

	mvc	__THREAD_per_address(8,%r14),__LC_PER_ADDRESS

	mvc	__THREAD_per_cause(2,%r14),__LC_PER_CODE

	mvc	__THREAD_per_paid(1,%r14),__LC_PER_ACCESS_ID

0:	REENABLE_IRQS

4:	REENABLE_IRQS

	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)

	larl	%r1,pgm_check_table

	llgh	%r10,__PT_INT_CODE+2(%r11)
@@ -489,7 +535,6 @@ ENTRY(io_int_handler) 
	lg	%r12,__LC_THREAD_INFO

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_IO_OLD_PSW

	HANDLE_SIE_INTERCEPT %r14,2

	SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT

	tmhh	%r8,0x0001		# interrupting from user?

	jz	.Lio_skip
@@ -667,7 +712,6 @@ ENTRY(ext_int_handler) 
	lg	%r12,__LC_THREAD_INFO

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_EXT_OLD_PSW

	HANDLE_SIE_INTERCEPT %r14,3

	SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT

	tmhh	%r8,0x0001		# interrupting from user ?

	jz	.Lext_skip
@@ -832,7 +876,6 @@ ENTRY(mcck_int_handler) 
	lg	%r12,__LC_THREAD_INFO

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_MCK_OLD_PSW

	HANDLE_SIE_INTERCEPT %r14,4

	tm	__LC_MCCK_CODE,0x80	# system damage?

	jo	.Lmcck_panic		# yes -> rest of mcck code invalid

	lghi	%r14,__LC_CPU_TIMER_SAVE_AREA
@@ -947,26 +990,13 @@ stack_overflow: 
	jg	kernel_stack_overflow

#endif



	.align	8

.Lcleanup_table:

	.quad	system_call

	.quad	.Lsysc_do_svc

	.quad	.Lsysc_tif

	.quad	.Lsysc_restore

	.quad	.Lsysc_done

	.quad	.Lio_tif

	.quad	.Lio_restore

	.quad	.Lio_done

	.quad	psw_idle

	.quad	.Lpsw_idle_end

	.quad	save_fpu_regs

	.quad	.Lsave_fpu_regs_end

	.quad	load_fpu_regs

	.quad	.Lload_fpu_regs_end

	.quad	__ctl_set_vx

	.quad	.L__ctl_set_vx_end



cleanup_critical:

#if IS_ENABLED(CONFIG_KVM)

	clg	%r9,BASED(.Lcleanup_table_sie)	# .Lsie_gmap

	jl	0f

	clg	%r9,BASED(.Lcleanup_table_sie+8)# .Lsie_done

	jl	.Lcleanup_sie

#endif

	clg	%r9,BASED(.Lcleanup_table)	# system_call

	jl	0f

	clg	%r9,BASED(.Lcleanup_table+8)	# .Lsysc_do_svc
@@ -1001,6 +1031,40 @@ cleanup_critical: 
	jl	.Lcleanup___ctl_set_vx

0:	br	%r14



	.align	8

.Lcleanup_table:

	.quad	system_call

	.quad	.Lsysc_do_svc

	.quad	.Lsysc_tif

	.quad	.Lsysc_restore

	.quad	.Lsysc_done

	.quad	.Lio_tif

	.quad	.Lio_restore

	.quad	.Lio_done

	.quad	psw_idle

	.quad	.Lpsw_idle_end

	.quad	save_fpu_regs

	.quad	.Lsave_fpu_regs_end

	.quad	load_fpu_regs

	.quad	.Lload_fpu_regs_end

	.quad	__ctl_set_vx

	.quad	.L__ctl_set_vx_end



#if IS_ENABLED(CONFIG_KVM)

.Lcleanup_table_sie:

	.quad	.Lsie_gmap

	.quad	.Lsie_done



.Lcleanup_sie:

	lg	%r9,__SF_EMPTY(%r15)		# get control block pointer

	tm	__LC_MACHINE_FLAGS+6,0x20	# MACHINE_FLAG_LPP

	jz	0f

	.insn	s,0xb2800000,__SF_EMPTY+16(%r15)# set host id

0:	ni	__SIE_PROG0C+3(%r9),0xfe	# no longer in SIE

	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce

	larl	%r9,sie_exit			# skip forward to sie_exit

	br	%r14

#endif



.Lcleanup_system_call:

	# check if stpt has been executed
@@ -1274,70 +1338,11 @@ cleanup_critical: 
	.quad	.L__critical_start

.Lcritical_length:

	.quad	.L__critical_end - .L__critical_start





#if IS_ENABLED(CONFIG_KVM)

/*

 * sie64a calling convention:

 * %r2 pointer to sie control block

 * %r3 guest register save area

 */

ENTRY(sie64a)

	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers

	stg	%r2,__SF_EMPTY(%r15)		# save control block pointer

	stg	%r3,__SF_EMPTY+8(%r15)		# save guest register save area

	xc	__SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason

	tm	__LC_CPU_FLAGS+7,_CIF_FPU	# load guest fp/vx registers ?

	jno	.Lsie_load_guest_gprs

	lg	%r12,__LC_THREAD_INFO		# load fp/vx regs save area

	brasl	%r14,load_fpu_regs		# load guest fp/vx regs

.Lsie_load_guest_gprs:

	lmg	%r0,%r13,0(%r3)			# load guest gprs 0-13

	lg	%r14,__LC_GMAP			# get gmap pointer

	ltgr	%r14,%r14

	jz	.Lsie_gmap

	lctlg	%c1,%c1,__GMAP_ASCE(%r14)	# load primary asce

.Lsie_gmap:

	lg	%r14,__SF_EMPTY(%r15)		# get control block pointer

	oi	__SIE_PROG0C+3(%r14),1		# we are going into SIE now

	tm	__SIE_PROG20+3(%r14),3		# last exit...

	jnz	.Lsie_skip

	tm	__LC_CPU_FLAGS+7,_CIF_FPU

	jo	.Lsie_skip			# exit if fp/vx regs changed

	LPP	__SF_EMPTY(%r15)		# set guest id

	sie	0(%r14)

	LPP	__SF_EMPTY+16(%r15)		# set host id

.Lsie_skip:

	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE

	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce

.Lsie_done:

# some program checks are suppressing. C code (e.g. do_protection_exception)

# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other

# instructions between sie64a and .Lsie_done should not cause program

# interrupts. So lets use a nop (47 00 00 00) as a landing pad.

# See also HANDLE_SIE_INTERCEPT

.Lrewind_pad:

	nop	0

	.globl sie_exit

sie_exit:

	lg	%r14,__SF_EMPTY+8(%r15)		# load guest register save area

	stmg	%r0,%r13,0(%r14)		# save guest gprs 0-13

	lmg	%r6,%r14,__SF_GPRS(%r15)	# restore kernel registers

	lg	%r2,__SF_EMPTY+24(%r15)		# return exit reason code

	br	%r14

.Lsie_fault:

	lghi	%r14,-EFAULT

	stg	%r14,__SF_EMPTY+24(%r15)	# set exit reason code

	j	sie_exit



	.align	8

.Lsie_critical:

.Lsie_critical_start:

	.quad	.Lsie_gmap

.Lsie_critical_length:

	.quad	.Lsie_done - .Lsie_gmap



	EX_TABLE(.Lrewind_pad,.Lsie_fault)

	EX_TABLE(sie_exit,.Lsie_fault)

#endif



	.section .rodata, "a"

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