From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>
Subject: [patch 06/10] Fix kernel preemption.
Date: Fri, 16 Nov 2007 15:24:47 +0100 [thread overview]
Message-ID: <20071116142527.043274700@de.ibm.com> (raw)
In-Reply-To: 20071116142441.484714036@de.ibm.com
[-- Attachment #1: 006-preemption.diff --]
[-- Type: text/plain, Size: 2901 bytes --]
From: Heiko Carstens <heiko.carstens@de.ibm.com>
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>
---
arch/s390/kernel/entry.S | 15 +++++----------
arch/s390/kernel/entry64.S | 12 ++----------
2 files changed, 7 insertions(+), 20 deletions(-)
diff -urpN linux-2.6/arch/s390/kernel/entry64.S linux-2.6-patched/arch/s390/kernel/entry64.S
--- linux-2.6/arch/s390/kernel/entry64.S 2007-11-16 14:27:41.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/entry64.S 2007-11-16 14:27:42.000000000 +0100
@@ -623,15 +623,8 @@ io_preempt:
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 @@ cleanup_io_leave_insn:
*/
.align 4
.Lconst:
-.Lc_pactive: .long PREEMPT_ACTIVE
.Lnr_syscalls: .long NR_syscalls
.L0x0130: .short 0x130
.L0x0140: .short 0x140
diff -urpN linux-2.6/arch/s390/kernel/entry.S linux-2.6-patched/arch/s390/kernel/entry.S
--- linux-2.6/arch/s390/kernel/entry.S 2007-11-16 14:27:41.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/entry.S 2007-11-16 14:27:42.000000000 +0100
@@ -640,15 +640,9 @@ io_preempt:
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 @@ cleanup_io_leave_insn:
.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 @@ cleanup_io_leave_insn:
.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
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
next prev parent reply other threads:[~2007-11-16 14:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-16 14:24 [patch 00/10] 2.6.24-rc s390 patch queue Martin Schwidefsky
2007-11-16 14:24 ` [patch 01/10] cio: change device sense procedure to work with pav aliases Martin Schwidefsky
2007-11-16 14:24 ` [patch 02/10] magic sysrq: check for in_atomic before doing an console_unblank Martin Schwidefsky
2007-11-16 14:24 ` [patch 03/10] Fix irq tracing and lockdep_sys_exit calls Martin Schwidefsky
2007-11-16 14:24 ` [patch 04/10] cmm: remove unused binary sysctls Martin Schwidefsky
2007-11-16 14:24 ` [patch 05/10] appldata: " Martin Schwidefsky
2007-11-16 14:24 ` Martin Schwidefsky [this message]
2007-11-16 14:24 ` [patch 07/10] Optimize storage key handling for anonymous pages Martin Schwidefsky
2007-11-16 14:24 ` [patch 08/10] Dont overwrite lowcores on smp_send_stop() Martin Schwidefsky
2007-11-16 14:24 ` [patch 09/10] Explicitly code allocpercpu calls in iucv Martin Schwidefsky
2007-11-16 14:24 ` [patch 10/10] Fix memory detection Martin Schwidefsky
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