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s390/nmi: use the normal asynchronous stack for machine checks

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If a machine checks is received while the CPU is in the kernel, only
the s390_do_machine_check function will be called. The call to
s390_handle_mcck is postponed until the CPU returns to user space.
Because of this it is safe to use the asynchronous stack for machine
checks even if the CPU is already handling an interrupt.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2015-06-22 17:28:14 +02:00
parent a359bb1190
commit 2acb94f431
1 changed files with 9 additions and 16 deletions
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25
arch/s390/kernel/entry.S
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@ -83,7 +83,7 @@ _PIF_WORK = (_PIF_PER_TRAP)
#endif
.endm
.macro SWITCH_ASYNC savearea,stack,shift,timer
.macro SWITCH_ASYNC savearea,timer
tmhh %r8,0x0001 # interrupting from user ?
jnz 1f
lgr %r14,%r9
@ -94,16 +94,16 @@ _PIF_WORK = (_PIF_PER_TRAP)
brasl %r14,cleanup_critical
tmhh %r8,0x0001 # retest problem state after cleanup
jnz 1f
0: lg %r14,\stack # are we already on the target stack?
0: lg %r14,__LC_ASYNC_STACK # are we already on the async stack?
slgr %r14,%r15
srag %r14,%r14,\shift
srag %r14,%r14,STACK_SHIFT
jnz 2f
CHECK_STACK 1<<\shift,\savearea
CHECK_STACK 1<<STACK_SHIFT,\savearea
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j 3f
1: LAST_BREAK %r14
UPDATE_VTIME %r14,%r15,\timer
2: lg %r15,\stack # load target stack
2: lg %r15,__LC_ASYNC_STACK # load async stack
3: la %r11,STACK_FRAME_OVERHEAD(%r15)
.endm
@ -539,8 +539,7 @@ ENTRY(io_int_handler)
lg %r12,__LC_THREAD_INFO
larl %r13,cleanup_critical
lmg %r8,%r9,__LC_IO_OLD_PSW
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT,\
__LC_ASYNC_ENTER_TIMER
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
stmg %r8,%r9,__PT_PSW(%r11)
@ -712,8 +711,7 @@ ENTRY(ext_int_handler)
lg %r12,__LC_THREAD_INFO
larl %r13,cleanup_critical
lmg %r8,%r9,__LC_EXT_OLD_PSW
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT,\
__LC_ASYNC_ENTER_TIMER
SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
stmg %r8,%r9,__PT_PSW(%r11)
@ -892,8 +890,7 @@ ENTRY(mcck_int_handler)
mvc __LC_MCCK_ENTER_TIMER(8),0(%r14)
3: tm __LC_MCCK_CODE+2,0x09 # mwp + ia of old psw valid?
jno .Lmcck_panic # no -> skip cleanup critical
SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+64,__LC_PANIC_STACK,PAGE_SHIFT,\
__LC_MCCK_ENTER_TIMER
SWITCH_ASYNC __LC_GPREGS_SAVE_AREA+64,__LC_MCCK_ENTER_TIMER
.Lmcck_skip:
lghi %r14,__LC_GPREGS_SAVE_AREA+64
stmg %r0,%r7,__PT_R0(%r11)
@ -928,12 +925,8 @@ ENTRY(mcck_int_handler)
lpswe __LC_RETURN_MCCK_PSW
.Lmcck_panic:
lg %r14,__LC_PANIC_STACK
slgr %r14,%r15
srag %r14,%r14,PAGE_SHIFT
jz 0f
lg %r15,__LC_PANIC_STACK
0: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j .Lmcck_skip
#