Commit 34525e1f authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390: store breaking event address only for program checks 



The principles of operations specifies that the breaking event address
is stored to the address 0x110 in the prefix page only for program checks.
The last branch in user space is lost as soon as a branch in kernel space
is executed after e.g. an svc. This makes it impossible to accurately
maintain the breaking event address for a user space process.

Simplify the code, just copy the current breaking event address from
0x110 to the task structure for program checks from user space.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 3b1bea01

arch/s390/kernel/entry.S

+12 −38
Original line number Diff line number Diff line
@@ -103,8 +103,7 @@ _PIF_WORK = (_PIF_PER_TRAP) 
	CHECK_STACK 1<<STACK_SHIFT,\savearea

	aghi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)

	j	3f

1:	LAST_BREAK %r14

	UPDATE_VTIME %r14,%r15,\timer

1:	UPDATE_VTIME %r14,%r15,\timer

2:	lg	%r15,__LC_ASYNC_STACK	# load async stack

3:	la	%r11,STACK_FRAME_OVERHEAD(%r15)

	.endm
@@ -121,18 +120,6 @@ _PIF_WORK = (_PIF_PER_TRAP) 
	mvc	__LC_LAST_UPDATE_TIMER(8),\enter_timer

	.endm



	.macro	LAST_BREAK scratch

	srag	\scratch,%r10,23

#ifdef CONFIG_HAVE_MARCH_Z990_FEATURES

	jz	.+10

	stg	%r10,__TASK_thread+__THREAD_last_break(%r12)

#else

	jz	.+14

	lghi	\scratch,__TASK_thread

	stg	%r10,__THREAD_last_break(\scratch,%r12)

#endif

	.endm



	.macro REENABLE_IRQS

	stg	%r8,__LC_RETURN_PSW

	ni	__LC_RETURN_PSW,0xbf
@@ -278,15 +265,14 @@ ENTRY(system_call) 
	stpt	__LC_SYNC_ENTER_TIMER

.Lsysc_stmg:

	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC

	lg	%r10,__LC_LAST_BREAK

	lg	%r12,__LC_CURRENT

	lghi	%r13,__TASK_thread

	lghi	%r14,_PIF_SYSCALL

.Lsysc_per:

	lg	%r15,__LC_KERNEL_STACK

	la	%r11,STACK_FRAME_OVERHEAD(%r15)	# pointer to pt_regs

	LAST_BREAK %r13

.Lsysc_vtime:

	UPDATE_VTIME %r10,%r13,__LC_SYNC_ENTER_TIMER

	UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER

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

	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_SYNC

	mvc	__PT_PSW(16,%r11),__LC_SVC_OLD_PSW
@@ -294,12 +280,7 @@ ENTRY(system_call) 
	stg	%r14,__PT_FLAGS(%r11)

.Lsysc_do_svc:

	# load address of system call table

#ifdef CONFIG_HAVE_MARCH_Z990_FEATURES

	lg	%r10,__TASK_thread+__THREAD_sysc_table(%r12)

#else

	lghi	%r13,__TASK_thread

	lg	%r10,__THREAD_sysc_table(%r13,%r12)

#endif

	llgh	%r8,__PT_INT_CODE+2(%r11)

	slag	%r8,%r8,2			# shift and test for svc 0

	jnz	.Lsysc_nr_ok
@@ -508,8 +489,7 @@ ENTRY(pgm_check_handler) 
1:	CHECK_STACK STACK_SIZE,__LC_SAVE_AREA_SYNC

	aghi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)

	j	3f

2:	LAST_BREAK %r14

	UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER

2:	UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER

	lg	%r15,__LC_KERNEL_STACK

	lgr	%r14,%r12

	aghi	%r14,__TASK_thread	# pointer to thread_struct
@@ -518,6 +498,7 @@ ENTRY(pgm_check_handler) 
	jz	3f

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

3:	la	%r11,STACK_FRAME_OVERHEAD(%r15)

	stg	%r10,__THREAD_last_break(%r14)

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

	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_SYNC

	stmg	%r8,%r9,__PT_PSW(%r11)
@@ -576,7 +557,6 @@ ENTRY(io_int_handler) 
	STCK	__LC_INT_CLOCK

	stpt	__LC_ASYNC_ENTER_TIMER

	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC

	lg	%r10,__LC_LAST_BREAK

	lg	%r12,__LC_CURRENT

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_IO_OLD_PSW
@@ -750,7 +730,6 @@ ENTRY(ext_int_handler) 
	STCK	__LC_INT_CLOCK

	stpt	__LC_ASYNC_ENTER_TIMER

	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC

	lg	%r10,__LC_LAST_BREAK

	lg	%r12,__LC_CURRENT

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_EXT_OLD_PSW
@@ -893,7 +872,6 @@ ENTRY(mcck_int_handler) 
	la	%r1,4095		# revalidate r1

	spt	__LC_CPU_TIMER_SAVE_AREA-4095(%r1)	# revalidate cpu timer

	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs

	lg	%r10,__LC_LAST_BREAK

	lg	%r12,__LC_CURRENT

	larl	%r13,cleanup_critical

	lmg	%r8,%r9,__LC_MCK_OLD_PSW
@@ -1088,9 +1066,10 @@ cleanup_critical: 
0:	# check if base register setup + TIF bit load has been done

	clg	%r9,BASED(.Lcleanup_system_call_insn+16)

	jhe	0f

	# set up saved registers r10 and r12

	stg	%r10,16(%r11)		# r10 last break

	stg	%r12,32(%r11)		# r12 task struct pointer

	# set up saved register r12 task struct pointer

	stg	%r12,32(%r11)

	# set up saved register r13 __TASK_thread offset

	mvc	40(8,%r11),BASED(.Lcleanup_system_call_const)

0:	# check if the user time update has been done

	clg	%r9,BASED(.Lcleanup_system_call_insn+24)

	jh	0f
@@ -1107,14 +1086,7 @@ cleanup_critical: 
	stg	%r15,__LC_SYSTEM_TIMER

0:	# update accounting time stamp

	mvc	__LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER

	# do LAST_BREAK

	lg	%r9,16(%r11)

	srag	%r9,%r9,23

	jz	0f

	lgr	%r9,%r12

	aghi	%r9,__TASK_thread

	mvc	__THREAD_last_break(8,%r9),16(%r11)

0:	# set up saved register r11

	# set up saved register r11

	lg	%r15,__LC_KERNEL_STACK

	la	%r9,STACK_FRAME_OVERHEAD(%r15)

	stg	%r9,24(%r11)		# r11 pt_regs pointer
@@ -1136,6 +1108,8 @@ cleanup_critical: 
	.quad	.Lsysc_per

	.quad	.Lsysc_vtime+36

	.quad	.Lsysc_vtime+42

.Lcleanup_system_call_const:

	.quad	__TASK_thread



.Lcleanup_sysc_tif:

	larl	%r9,.Lsysc_tif

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