[PATCH] s390: improved machine check handling
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>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index c0e09b3..5b262b5 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -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>
@@ -49,9 +50,9 @@
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
@@ -121,7 +122,11 @@
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
@@ -161,6 +166,13 @@
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
@@ -185,6 +197,7 @@
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:
@@ -234,6 +247,8 @@
# 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
@@ -253,6 +268,14 @@
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
#
sysc_sigpending:
@@ -430,6 +453,7 @@
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)
@@ -468,6 +492,7 @@
#
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)
@@ -493,6 +518,7 @@
#
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)
@@ -521,6 +547,7 @@
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)
@@ -578,9 +605,11 @@
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
@@ -588,6 +617,14 @@
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
#
io_reschedule:
@@ -621,6 +658,7 @@
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)
@@ -642,19 +680,62 @@
.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
@@ -742,7 +823,7 @@
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
@@ -760,6 +841,7 @@
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
@@ -834,6 +916,8 @@
* 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