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[S390] ftrace: fix kernel stack backchain walking

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With CONFIG_IRQSOFF_TRACER the trace_hardirqs_off() function includes
a call to __builtin_return_address(1). But we calltrace_hardirqs_off()
from early entry code. There we have just a single stack frame.
So this results in a kernel stack backchain walk that would walk beyond
the kernel stack. Following the NULL terminated backchain this results
in a lowcore read access.

To fix this we simply call trace_hardirqs_off_caller() and pass the
current instruction pointer.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens
2008-11-14 18:18:05 +01:00
committed by Martin Schwidefsky
parent 632448f650
commit 50bec4ce5d
2 changed files with 18 additions and 11 deletions
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11
arch/s390/kernel/entry64.S
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@ -61,19 +61,22 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
#ifdef CONFIG_TRACE_IRQFLAGS
.macro TRACE_IRQS_ON
brasl %r14,trace_hardirqs_on
basr %r2,%r0
brasl %r14,trace_hardirqs_on_caller
.endm
.macro TRACE_IRQS_OFF
brasl %r14,trace_hardirqs_off
basr %r2,%r0
brasl %r14,trace_hardirqs_off_caller
.endm
.macro TRACE_IRQS_CHECK
basr %r2,%r0
tm SP_PSW(%r15),0x03 # irqs enabled?
jz 0f
brasl %r14,trace_hardirqs_on
brasl %r14,trace_hardirqs_on_caller
j 1f
0: brasl %r14,trace_hardirqs_off
0: brasl %r14,trace_hardirqs_off_caller
1:
.endm
#else