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DateThu, 04 Feb 2010 09:11:37 -0800
FromGreg KH <>
Subject[06/74] S390: fix single stepped svcs with TRACE_IRQFLAGS=y
2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Martin Schwidefsky <schwidefsky@de.ibm.com>

commit 21ec7f6dbf10492ce9a21718040677d3e68bd57d upstream.

If irq flags tracing is enabled the TRACE_IRQS_ON macros expands to
a function call which clobbers registers %r0-%r5. The macro is used
in the code path for single stepped system calls. The argument
registers %r2-%r6 need to be restored from the stack before the system
call function is called.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/s390/kernel/entry.S | 1 +
arch/s390/kernel/entry64.S | 1 +
2 files changed, 2 insertions(+)
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -549,6 +549,7 @@ pgm_svcper:
mvc __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
oi __TI_flags+7(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
TRACE_IRQS_ON
+ lmg %r2,%r6,SP_R2(%r15) # load svc arguments
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
j sysc_do_svc

--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -571,6 +571,7 @@ pgm_svcper:
mvc __THREAD_per+__PER_access_id(1,%r8),__LC_PER_ACCESS_ID
oi __TI_flags+3(%r9),_TIF_SINGLE_STEP # set TIF_SINGLE_STEP
TRACE_IRQS_ON
+ lm %r2,%r6,SP_R2(%r15) # load svc arguments
stosm __SF_EMPTY(%r15),0x03 # reenable interrupts
b BASED(sysc_do_svc)




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