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DateFri, 14 Aug 2009 13:25:41 +0200
FromMartin Schwidefsky <>
Subject[patch 24/34] move (io|sysc)_restore_trace_psw into .data section
From: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>

The sysc_restore_trace_psw and io_restore_trace_psw storage locations
are created in the .text section. When creating and IPLing from a named
saved system (NSS), writing to these locations causes a protection exception
(because the .text section is mapped as shared read-only in the NSS).

To permit write access, move the storage locations into the .data section.

The problem occurs only when CONFIG_TRACE_IRQFLAGS is set.
The git commmit that has introduced these variables is:
411788ea7fca01ee803af8225ac35807b4d02050

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/kernel/entry.S | 16 ++++++++++++++--
arch/s390/kernel/entry64.S | 4 ++++
2 files changed, 18 insertions(+), 2 deletions(-)
Index: quilt-2.6/arch/s390/kernel/entry64.S
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/entry64.S
+++ quilt-2.6/arch/s390/kernel/entry64.S
@@ -284,10 +284,12 @@ sysc_leave:
sysc_done:

#ifdef CONFIG_TRACE_IRQFLAGS
+ .section .data,"aw",@progbits
.align 8
.globl sysc_restore_trace_psw
sysc_restore_trace_psw:
.quad 0, sysc_restore_trace
+ .previous
#endif

#
@@ -595,10 +597,12 @@ io_leave:
io_done:

#ifdef CONFIG_TRACE_IRQFLAGS
+ .section .data,"aw",@progbits
.align 8
.globl io_restore_trace_psw
io_restore_trace_psw:
.quad 0, io_restore_trace
+ .previous
#endif

#
Index: quilt-2.6/arch/s390/kernel/entry.S
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/entry.S
+++ quilt-2.6/arch/s390/kernel/entry.S
@@ -278,7 +278,8 @@ sysc_return:
bnz BASED(sysc_work) # there is work to do (signals etc.)
sysc_restore:
#ifdef CONFIG_TRACE_IRQFLAGS
- la %r1,BASED(sysc_restore_trace_psw)
+ la %r1,BASED(sysc_restore_trace_psw_addr)
+ l %r1,0(%r1)
lpsw 0(%r1)
sysc_restore_trace:
TRACE_IRQS_CHECK
@@ -289,10 +290,15 @@ sysc_leave:
sysc_done:

#ifdef CONFIG_TRACE_IRQFLAGS
+sysc_restore_trace_psw_addr:
+ .long sysc_restore_trace_psw
+
+ .section .data,"aw",@progbits
.align 8
.globl sysc_restore_trace_psw
sysc_restore_trace_psw:
.long 0, sysc_restore_trace + 0x80000000
+ .previous
#endif

#
@@ -606,7 +612,8 @@ io_return:
bnz BASED(io_work) # there is work to do (signals etc.)
io_restore:
#ifdef CONFIG_TRACE_IRQFLAGS
- la %r1,BASED(io_restore_trace_psw)
+ la %r1,BASED(io_restore_trace_psw_addr)
+ l %r1,0(%r1)
lpsw 0(%r1)
io_restore_trace:
TRACE_IRQS_CHECK
@@ -617,10 +624,15 @@ io_leave:
io_done:

#ifdef CONFIG_TRACE_IRQFLAGS
+io_restore_trace_psw_addr:
+ .long io_restore_trace_psw
+
+ .section .data,"aw",@progbits
.align 8
.globl io_restore_trace_psw
io_restore_trace_psw:
.long 0, io_restore_trace + 0x80000000
+ .previous
#endif

#
--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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