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[PATCH] s390: machine check handler bugs
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The new machine check handler still has a few bugs.

1) The system entry time has to be stored in the machine check handler,

2) the machine check return psw may not be stored at the usual place
   because it might overwrite the return psw of the interrupted context,

3) the return address for the call to s390_handle_mcck in the i/o interrupt
   handler is not correct,

4) the system call cleanup has to take the different save area of the
   machine check handler into account,

5) the machine check handler may not call UPDATE_VTIME before
   CREATE_STACK_FRAME, and

6) the io leave path needs a critical section cleanup to make sure that the
   TIF_MCCK_PENDING bit is really checked before switching back to user space.

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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Martin Schwidefsky authored and Linus Torvalds committed Sep 5, 2005
1 parent 4c13986 commit ae6aa2e
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Showing 4 changed files with 181 additions and 58 deletions.
116 changes: 88 additions & 28 deletions arch/s390/kernel/entry.S
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Original file line number Diff line number Diff line change
Expand Up @@ -138,14 +138,14 @@ STACK_SIZE = 1 << STACK_SHIFT
st %r12,__SF_BACKCHAIN(%r15) # clear back chain
.endm

.macro RESTORE_ALL sync
mvc __LC_RETURN_PSW(8),SP_PSW(%r15) # move user PSW to lowcore
.macro RESTORE_ALL psworg,sync
mvc \psworg(8),SP_PSW(%r15) # move user PSW to lowcore
.if !\sync
ni __LC_RETURN_PSW+1,0xfd # clear wait state bit
ni \psworg+1,0xfd # clear wait state bit
.endif
lm %r0,%r15,SP_R0(%r15) # load gprs 0-15 of user
STORE_TIMER __LC_EXIT_TIMER
lpsw __LC_RETURN_PSW # back to caller
lpsw \psworg # back to caller
.endm

/*
Expand Down Expand Up @@ -235,7 +235,7 @@ sysc_return:
tm __TI_flags+3(%r9),_TIF_WORK_SVC
bnz BASED(sysc_work) # there is work to do (signals etc.)
sysc_leave:
RESTORE_ALL 1
RESTORE_ALL __LC_RETURN_PSW,1

#
# recheck if there is more work to do
Expand Down Expand Up @@ -312,8 +312,6 @@ sysc_singlestep:
la %r14,BASED(sysc_return) # load adr. of system return
br %r1 # branch to do_single_step

__critical_end:

#
# call trace before and after sys_call
#
Expand Down Expand Up @@ -571,7 +569,8 @@ io_return:
tm __TI_flags+3(%r9),_TIF_WORK_INT
bnz BASED(io_work) # there is work to do (signals etc.)
io_leave:
RESTORE_ALL 0
RESTORE_ALL __LC_RETURN_PSW,0
io_done:

#ifdef CONFIG_PREEMPT
io_preempt:
Expand Down Expand Up @@ -621,7 +620,7 @@ io_work_loop:
#
io_mcck_pending:
l %r1,BASED(.Ls390_handle_mcck)
l %r14,BASED(io_work_loop)
la %r14,BASED(io_work_loop)
br %r1 # TIF bit will be cleared by handler

#
Expand Down Expand Up @@ -674,13 +673,16 @@ ext_no_vtime:
basr %r14,%r1
b BASED(io_return)

__critical_end:

/*
* Machine check handler routines
*/

.globl mcck_int_handler
mcck_int_handler:
spt __LC_CPU_TIMER_SAVE_AREA # revalidate cpu timer
mvc __LC_ASYNC_ENTER_TIMER(8),__LC_CPU_TIMER_SAVE_AREA
lm %r0,%r15,__LC_GPREGS_SAVE_AREA # revalidate gprs
SAVE_ALL_BASE __LC_SAVE_AREA+32
la %r12,__LC_MCK_OLD_PSW
Expand All @@ -693,17 +695,8 @@ mcck_int_handler:
mvc __LC_ASYNC_ENTER_TIMER(8),__LC_LAST_UPDATE_TIMER
mvc __LC_SYNC_ENTER_TIMER(8),__LC_LAST_UPDATE_TIMER
mvc __LC_EXIT_TIMER(8),__LC_LAST_UPDATE_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?
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
Expand All @@ -720,6 +713,16 @@ mcck_int_main:
be BASED(0f)
l %r15,__LC_PANIC_STACK # load panic stack
0: CREATE_STACK_FRAME __LC_MCK_OLD_PSW,__LC_SAVE_AREA+32
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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
l %r9,__LC_THREAD_INFO # load pointer to thread_info struct
la %r2,SP_PTREGS(%r15) # load pt_regs
l %r1,BASED(.Ls390_mcck)
Expand All @@ -737,7 +740,7 @@ mcck_int_main:
l %r1,BASED(.Ls390_handle_mcck)
basr %r14,%r1 # call machine check handler
mcck_return:
RESTORE_ALL 0
RESTORE_ALL __LC_RETURN_MCCK_PSW,0

#ifdef CONFIG_SMP
/*
Expand Down Expand Up @@ -803,6 +806,10 @@ cleanup_table_sysc_leave:
.long sysc_leave + 0x80000000, sysc_work_loop + 0x80000000
cleanup_table_sysc_work_loop:
.long sysc_work_loop + 0x80000000, sysc_reschedule + 0x80000000
cleanup_table_io_leave:
.long io_leave + 0x80000000, io_done + 0x80000000
cleanup_table_io_work_loop:
.long io_work_loop + 0x80000000, io_mcck_pending + 0x80000000

cleanup_critical:
clc 4(4,%r12),BASED(cleanup_table_system_call)
Expand All @@ -824,11 +831,27 @@ cleanup_critical:
bl BASED(0f)
clc 4(4,%r12),BASED(cleanup_table_sysc_work_loop+4)
bl BASED(cleanup_sysc_return)
0:
clc 4(4,%r12),BASED(cleanup_table_io_leave)
bl BASED(0f)
clc 4(4,%r12),BASED(cleanup_table_io_leave+4)
bl BASED(cleanup_io_leave)
0:
clc 4(4,%r12),BASED(cleanup_table_io_work_loop)
bl BASED(0f)
clc 4(4,%r12),BASED(cleanup_table_io_work_loop+4)
bl BASED(cleanup_io_return)
0:
br %r14

cleanup_system_call:
mvc __LC_RETURN_PSW(8),0(%r12)
c %r12,BASED(.Lmck_old_psw)
be BASED(0f)
la %r12,__LC_SAVE_AREA+16
b BASED(1f)
0: la %r12,__LC_SAVE_AREA+32
1:
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn+4)
bh BASED(0f)
Expand All @@ -838,11 +861,13 @@ cleanup_system_call:
#endif
clc __LC_RETURN_PSW+4(4),BASED(cleanup_system_call_insn)
bh BASED(0f)
mvc __LC_SAVE_AREA(16),__LC_SAVE_AREA+16
0: st %r13,__LC_SAVE_AREA+20
mvc __LC_SAVE_AREA(16),0(%r12)
0: st %r13,4(%r12)
st %r12,__LC_SAVE_AREA+48 # argh
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
l %r12,__LC_SAVE_AREA+48 # argh
st %r15,12(%r12)
lh %r7,0x8a
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
cleanup_vtime:
Expand Down Expand Up @@ -879,24 +904,58 @@ cleanup_sysc_return:

cleanup_sysc_leave:
clc 4(4,%r12),BASED(cleanup_sysc_leave_insn)
be BASED(0f)
be BASED(2f)
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
clc 4(4,%r12),BASED(cleanup_sysc_leave_insn+4)
be BASED(0f)
be BASED(2f)
#endif
mvc __LC_RETURN_PSW(8),SP_PSW(%r15)
mvc __LC_SAVE_AREA+16(16),SP_R12(%r15)
lm %r0,%r11,SP_R0(%r15)
c %r12,BASED(.Lmck_old_psw)
bne BASED(0f)
mvc __LC_SAVE_AREA+32(16),SP_R12(%r15)
b BASED(1f)
0: mvc __LC_SAVE_AREA+16(16),SP_R12(%r15)
1: lm %r0,%r11,SP_R0(%r15)
l %r15,SP_R15(%r15)
0: la %r12,__LC_RETURN_PSW
2: la %r12,__LC_RETURN_PSW
br %r14
cleanup_sysc_leave_insn:
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
.long sysc_leave + 14 + 0x80000000
#endif
.long sysc_leave + 10 + 0x80000000

cleanup_io_return:
mvc __LC_RETURN_PSW(4),0(%r12)
mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_io_work_loop)
la %r12,__LC_RETURN_PSW
br %r14

cleanup_io_leave:
clc 4(4,%r12),BASED(cleanup_io_leave_insn)
be BASED(2f)
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER
clc 4(4,%r12),BASED(cleanup_io_leave_insn+4)
be BASED(2f)
#endif
mvc __LC_RETURN_PSW(8),SP_PSW(%r15)
c %r12,BASED(.Lmck_old_psw)
bne BASED(0f)
mvc __LC_SAVE_AREA+32(16),SP_R12(%r15)
b BASED(1f)
0: mvc __LC_SAVE_AREA+16(16),SP_R12(%r15)
1: lm %r0,%r11,SP_R0(%r15)
l %r15,SP_R15(%r15)
2: la %r12,__LC_RETURN_PSW
br %r14
cleanup_io_leave_insn:
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
.long io_leave + 18 + 0x80000000
#endif
.long io_leave + 14 + 0x80000000

/*
* Integer constants
*/
Expand All @@ -918,6 +977,7 @@ cleanup_sysc_leave_insn:
.Ls390_mcck: .long s390_do_machine_check
.Ls390_handle_mcck:
.long s390_handle_mcck
.Lmck_old_psw: .long __LC_MCK_OLD_PSW
.Ldo_IRQ: .long do_IRQ
.Ldo_extint: .long do_extint
.Ldo_signal: .long do_signal
Expand Down
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