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[PATCH] s390: improved machine check handling
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Improved machine check handling.  Kernel is now able to receive machine checks
while in kernel mode (system call, interrupt and program check handling).
Also register validation is now performed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Heiko Carstens authored and Linus Torvalds committed Jun 25, 2005
1 parent f901e5d commit 77fa224
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Showing 12 changed files with 576 additions and 135 deletions.
102 changes: 93 additions & 9 deletions arch/s390/kernel/entry.S
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Hartmut Penner (hp@de.ibm.com),
* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
* Heiko Carstens <heiko.carstens@de.ibm.com>
*/

#include <linux/sys.h>
Expand Down Expand Up @@ -49,9 +50,9 @@ SP_ILC = STACK_FRAME_OVERHEAD + __PT_ILC
SP_TRAP = STACK_FRAME_OVERHEAD + __PT_TRAP
SP_SIZE = STACK_FRAME_OVERHEAD + __PT_SIZE

_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING | \
_TIF_RESTART_SVC | _TIF_SINGLE_STEP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)

STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE = 1 << STACK_SHIFT
Expand Down Expand Up @@ -121,7 +122,11 @@ STACK_SIZE = 1 << STACK_SHIFT
bz BASED(stack_overflow)
3:
#endif
2: s %r15,BASED(.Lc_spsize) # make room for registers & psw
2:
.endm

.macro CREATE_STACK_FRAME psworg,savearea
s %r15,BASED(.Lc_spsize) # make room for registers & psw
mvc SP_PSW(8,%r15),0(%r12) # move user PSW to stack
la %r12,\psworg
st %r2,SP_ORIG_R2(%r15) # store original content of gpr 2
Expand Down Expand Up @@ -161,6 +166,13 @@ __switch_to_base:
be __switch_to_noper-__switch_to_base(%r1) # we got away w/o bashing TLB's
lctl %c9,%c11,__THREAD_per(%r3) # Nope we didn't
__switch_to_noper:
l %r4,__THREAD_info(%r2) # get thread_info of prev
tm __TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
bz __switch_to_no_mcck-__switch_to_base(%r1)
ni __TI_flags+3(%r4),255-_TIF_MCCK_PENDING # clear flag in prev
l %r4,__THREAD_info(%r3) # get thread_info of next
oi __TI_flags+3(%r4),_TIF_MCCK_PENDING # set it in next
__switch_to_no_mcck:
stm %r6,%r15,__SF_GPRS(%r15)# store __switch_to registers of prev task
st %r15,__THREAD_ksp(%r2) # store kernel stack to prev->tss.ksp
l %r15,__THREAD_ksp(%r3) # load kernel stack from next->tss.ksp
Expand All @@ -185,6 +197,7 @@ system_call:
sysc_saveall:
SAVE_ALL_BASE __LC_SAVE_AREA
SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
lh %r7,0x8a # get svc number from lowcore
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
sysc_vtime:
Expand Down Expand Up @@ -234,6 +247,8 @@ sysc_work_loop:
# One of the work bits is on. Find out which one.
#
sysc_work:
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
Expand All @@ -252,6 +267,14 @@ sysc_reschedule:
la %r14,BASED(sysc_work_loop)
br %r1 # call scheduler

#
# _TIF_MCCK_PENDING is set, call handler
#
sysc_mcck_pending:
l %r1,BASED(.Ls390_handle_mcck)
la %r14,BASED(sysc_work_loop)
br %r1 # TIF bit will be cleared by handler

#
# _TIF_SIGPENDING is set, call do_signal
#
Expand Down Expand Up @@ -430,6 +453,7 @@ pgm_check_handler:
tm __LC_PGM_INT_CODE+1,0x80 # check whether we got a per exception
bnz BASED(pgm_per) # got per exception -> special case
SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
bz BASED(pgm_no_vtime)
Expand Down Expand Up @@ -468,6 +492,7 @@ pgm_per:
#
pgm_per_std:
SAVE_ALL __LC_PGM_OLD_PSW,__LC_SAVE_AREA,1
CREATE_STACK_FRAME __LC_PGM_OLD_PSW,__LC_SAVE_AREA
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
bz BASED(pgm_no_vtime2)
Expand All @@ -493,6 +518,7 @@ pgm_no_vtime2:
#
pgm_svcper:
SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
bz BASED(pgm_no_vtime3)
Expand Down Expand Up @@ -521,6 +547,7 @@ io_int_handler:
stck __LC_INT_CLOCK
SAVE_ALL_BASE __LC_SAVE_AREA+16
SAVE_ALL __LC_IO_OLD_PSW,__LC_SAVE_AREA+16,0
CREATE_STACK_FRAME __LC_IO_OLD_PSW,__LC_SAVE_AREA+16
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
bz BASED(io_no_vtime)
Expand Down Expand Up @@ -578,15 +605,25 @@ io_work:
lr %r15,%r1
#
# One of the work bits is on. Find out which one.
# Checked are: _TIF_SIGPENDING and _TIF_NEED_RESCHED
# Checked are: _TIF_SIGPENDING, _TIF_NEED_RESCHED and _TIF_MCCK_PENDING
#
io_work_loop:
tm __TI_flags+3(%r9),_TIF_MCCK_PENDING
bo BASED(io_mcck_pending)
tm __TI_flags+3(%r9),_TIF_NEED_RESCHED
bo BASED(io_reschedule)
tm __TI_flags+3(%r9),_TIF_SIGPENDING
bo BASED(io_sigpending)
b BASED(io_leave)

#
# _TIF_MCCK_PENDING is set, call handler
#
io_mcck_pending:
l %r1,BASED(.Ls390_handle_mcck)
l %r14,BASED(io_work_loop)
br %r1 # TIF bit will be cleared by handler

#
# _TIF_NEED_RESCHED is set, call schedule
#
Expand Down Expand Up @@ -621,6 +658,7 @@ ext_int_handler:
stck __LC_INT_CLOCK
SAVE_ALL_BASE __LC_SAVE_AREA+16
SAVE_ALL __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16,0
CREATE_STACK_FRAME __LC_EXT_OLD_PSW,__LC_SAVE_AREA+16
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
bz BASED(ext_no_vtime)
Expand All @@ -642,19 +680,62 @@ ext_no_vtime:

.globl mcck_int_handler
mcck_int_handler:
STORE_TIMER __LC_ASYNC_ENTER_TIMER
spt __LC_CPU_TIMER_SAVE_AREA # revalidate cpu timer
lm %r0,%r15,__LC_GPREGS_SAVE_AREA # revalidate gprs
SAVE_ALL_BASE __LC_SAVE_AREA+32
SAVE_ALL __LC_MCK_OLD_PSW,__LC_SAVE_AREA+32,0
la %r12,__LC_MCK_OLD_PSW
tm __LC_MCCK_CODE,0x80 # system damage?
bo BASED(mcck_int_main) # yes -> rest of mcck code invalid
tm __LC_MCCK_CODE+5,0x02 # stored cpu timer value valid?
bo BASED(0f)
spt __LC_LAST_UPDATE_TIMER # revalidate cpu timer
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
tm SP_PSW+1(%r15),0x01 # interrupting from user ?
mvc __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__LC_EXIT_TIMER
0: tm __LC_MCCK_CODE+2,0x08 # mwp of old psw valid?
bno BASED(mcck_no_vtime) # no -> skip cleanup critical
tm __LC_MCK_OLD_PSW+1,0x01 # interrupting from user ?
bz BASED(mcck_no_vtime)
UPDATE_VTIME __LC_EXIT_TIMER,__LC_ASYNC_ENTER_TIMER,__LC_USER_TIMER
UPDATE_VTIME __LC_LAST_UPDATE_TIMER,__LC_EXIT_TIMER,__LC_SYSTEM_TIMER
mvc __LC_LAST_UPDATE_TIMER(8),__LC_ASYNC_ENTER_TIMER
mcck_no_vtime:
#endif
0:
tm __LC_MCCK_CODE+2,0x09 # mwp + ia of old psw valid?
bno BASED(mcck_int_main) # no -> skip cleanup critical
tm __LC_MCK_OLD_PSW+1,0x01 # test problem state bit
bnz BASED(mcck_int_main) # from user -> load async stack
clc __LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_end)
bhe BASED(mcck_int_main)
clc __LC_MCK_OLD_PSW+4(4),BASED(.Lcritical_start)
bl BASED(mcck_int_main)
l %r14,BASED(.Lcleanup_critical)
basr %r14,%r14
mcck_int_main:
l %r14,__LC_PANIC_STACK # are we already on the panic stack?
slr %r14,%r15
sra %r14,PAGE_SHIFT
be BASED(0f)
l %r15,__LC_PANIC_STACK # load panic stack
0: CREATE_STACK_FRAME __LC_MCK_OLD_PSW,__LC_SAVE_AREA+32
l %r9,__LC_THREAD_INFO # load pointer to thread_info struct
la %r2,SP_PTREGS(%r15) # load pt_regs
l %r1,BASED(.Ls390_mcck)
basr %r14,%r1 # call machine check handler
basr %r14,%r1 # call machine check handler
tm SP_PSW+1(%r15),0x01 # returning to user ?
bno BASED(mcck_return)
l %r1,__LC_KERNEL_STACK # switch to kernel stack
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
stosm __SF_EMPTY(%r15),0x04 # turn dat on
tm __TI_flags+3(%r9),_TIF_MCCK_PENDING
bno BASED(mcck_return)
l %r1,BASED(.Ls390_handle_mcck)
basr %r14,%r1 # call machine check handler
mcck_return:
RESTORE_ALL 0

Expand Down Expand Up @@ -742,7 +823,7 @@ cleanup_critical:
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_leave)
bl BASED(cleanup_sysc_return)
0:
br %r14

Expand All @@ -760,6 +841,7 @@ cleanup_system_call:
mvc __LC_SAVE_AREA(16),__LC_SAVE_AREA+16
0: st %r13,__LC_SAVE_AREA+20
SAVE_ALL __LC_SVC_OLD_PSW,__LC_SAVE_AREA,1
CREATE_STACK_FRAME __LC_SVC_OLD_PSW,__LC_SAVE_AREA
st %r15,__LC_SAVE_AREA+28
lh %r7,0x8a
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
Expand Down Expand Up @@ -834,6 +916,8 @@ cleanup_sysc_leave_insn:
* Symbol constants
*/
.Ls390_mcck: .long s390_do_machine_check
.Ls390_handle_mcck:
.long s390_handle_mcck
.Ldo_IRQ: .long do_IRQ
.Ldo_extint: .long do_extint
.Ldo_signal: .long do_signal
Expand Down
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