[S390] Fix kernel preemption.
When returning from IRQ handling and TIF_NEED_RESCHED is set we must
call preempt_schedule_irq() instead of schedule().
Otherwise the BKL might be unlocked in schedule() and therfore
everything that relies on the BKL is broken.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 764d561..b2b2edc 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -640,15 +640,9 @@
io_resume_loop:
tm __TI_flags+3(%r9),_TIF_NEED_RESCHED
bno BASED(io_restore)
- mvc __TI_precount(4,%r9),BASED(.Lc_pactive)
- TRACE_IRQS_ON
- stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
- l %r1,BASED(.Lschedule)
- basr %r14,%r1 # call schedule
- stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
- TRACE_IRQS_OFF
- xc __TI_precount(4,%r9),__TI_precount(%r9)
- b BASED(io_resume_loop)
+ l %r1,BASED(.Lpreempt_schedule_irq)
+ la %r14,BASED(io_resume_loop)
+ br %r1 # call schedule
#endif
#
@@ -1062,7 +1056,6 @@
.align 4
.Lc_spsize: .long SP_SIZE
.Lc_overhead: .long STACK_FRAME_OVERHEAD
-.Lc_pactive: .long PREEMPT_ACTIVE
.Lnr_syscalls: .long NR_syscalls
.L0x018: .short 0x018
.L0x020: .short 0x020
@@ -1086,6 +1079,8 @@
.Lexecve_tail: .long execve_tail
.Ljump_table: .long pgm_check_table
.Lschedule: .long schedule
+.Lpreempt_schedule_irq:
+ .long preempt_schedule_irq
.Ltrace: .long syscall_trace
.Lschedtail: .long schedule_tail
.Lsysc_table: .long sys_call_table
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index e15c80e..a3e47b8 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -623,15 +623,8 @@
io_resume_loop:
tm __TI_flags+7(%r9),_TIF_NEED_RESCHED
jno io_restore
- larl %r1,.Lc_pactive
- mvc __TI_precount(4,%r9),0(%r1)
- TRACE_IRQS_ON
- stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
- brasl %r14,schedule # call schedule
- stnsm __SF_EMPTY(%r15),0xfc # disable I/O and ext. interrupts
- TRACE_IRQS_OFF
- xc __TI_precount(4,%r9),__TI_precount(%r9)
- j io_resume_loop
+ larl %r14,io_resume_loop
+ jg preempt_schedule_irq
#endif
#
@@ -1029,7 +1022,6 @@
*/
.align 4
.Lconst:
-.Lc_pactive: .long PREEMPT_ACTIVE
.Lnr_syscalls: .long NR_syscalls
.L0x0130: .short 0x130
.L0x0140: .short 0x140
