Gitweb: http://git.kernel.org/linus/176b1803ce4690d0dd94e16f118dbd14af045034
Commit: 176b1803ce4690d0dd94e16f118dbd14af045034
Parent: 35ac734f72d846f250c0344913a91f954ea764c3
Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
AuthorDate: Fri Apr 9 13:43:00 2010 +0200
Committer: Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>
CommitDate: Fri Apr 9 13:43:02 2010 +0200
[S390] fix io_return critical section cleanup
If a machine check interrupts the io interrupt handler on one of the
instructions between io_return and io_leave the critical section
cleanup code will move the return psw to io_work_loop. By doing that
the switch from the asynchronous interrupt stack to the process stack
is skipped. If e.g. TIF_NEED_RESCHED is set things break because
the scheduler is called with the asynchronous interrupts stack.
Moving the psw back to io_return instead fixes the problem.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/kernel/entry.S | 8 +++++++-
arch/s390/kernel/entry64.S | 8 +++++++-
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 4348f9b..6af7045 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -964,7 +964,7 @@ cleanup_critical:
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)
+ bl BASED(cleanup_io_work_loop)
0:
br %r14
@@ -1039,6 +1039,12 @@ cleanup_sysc_leave_insn:
cleanup_io_return:
mvc __LC_RETURN_PSW(4),0(%r12)
+ mvc __LC_RETURN_PSW+4(4),BASED(cleanup_table_io_return)
+ la %r12,__LC_RETURN_PSW
+ br %r14
+
+cleanup_io_work_loop:
+ 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
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 29fd0f1..52106d5 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -946,7 +946,7 @@ cleanup_critical:
clc 8(8,%r12),BASED(cleanup_table_io_work_loop)
jl 0f
clc 8(8,%r12),BASED(cleanup_table_io_work_loop+8)
- jl cleanup_io_return
+ jl cleanup_io_work_loop
0:
br %r14
@@ -1021,6 +1021,12 @@ cleanup_sysc_leave_insn:
cleanup_io_return:
mvc __LC_RETURN_PSW(8),0(%r12)
+ mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_return)
+ la %r12,__LC_RETURN_PSW
+ br %r14
+
+cleanup_io_work_loop:
+ mvc __LC_RETURN_PSW(8),0(%r12)
mvc __LC_RETURN_PSW+8(8),BASED(cleanup_table_io_work_loop)
la %r12,__LC_RETURN_PSW
br %r14
--
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