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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-11-14 18:18:05 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-11-14 18:18:53 +0100 |
| commit | 50bec4ce5d36ebf96189dcc54e20c7fce4bf61bf (patch) | |
| tree | 5f04e012e882ed15f9c7f1f45b0e9a27dd2656f5 /arch/s390/kernel/entry.S | |
| parent | 632448f65001c4935ed0d3bb362017d773da2eca (diff) | |
| download | op-kernel-dev-50bec4ce5d36ebf96189dcc54e20c7fce4bf61bf.zip op-kernel-dev-50bec4ce5d36ebf96189dcc54e20c7fce4bf61bf.tar.gz | |
[S390] ftrace: fix kernel stack backchain walking
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>
Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 5f0c4fb..08844fc 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -61,22 +61,25 @@ STACK_SIZE = 1 << STACK_SHIFT #ifdef CONFIG_TRACE_IRQFLAGS .macro TRACE_IRQS_ON - l %r1,BASED(.Ltrace_irq_on) + basr %r2,%r0 + l %r1,BASED(.Ltrace_irq_on_caller) basr %r14,%r1 .endm .macro TRACE_IRQS_OFF - l %r1,BASED(.Ltrace_irq_off) + basr %r2,%r0 + l %r1,BASED(.Ltrace_irq_off_caller) basr %r14,%r1 .endm .macro TRACE_IRQS_CHECK + basr %r2,%r0 tm SP_PSW(%r15),0x03 # irqs enabled? jz 0f - l %r1,BASED(.Ltrace_irq_on) + l %r1,BASED(.Ltrace_irq_on_caller) basr %r14,%r1 j 1f -0: l %r1,BASED(.Ltrace_irq_off) +0: l %r1,BASED(.Ltrace_irq_off_caller) basr %r14,%r1 1: .endm @@ -1113,9 +1116,10 @@ cleanup_io_leave_insn: .Lschedtail: .long schedule_tail .Lsysc_table: .long sys_call_table #ifdef CONFIG_TRACE_IRQFLAGS -.Ltrace_irq_on: .long trace_hardirqs_on -.Ltrace_irq_off: - .long trace_hardirqs_off +.Ltrace_irq_on_caller: + .long trace_hardirqs_on_caller +.Ltrace_irq_off_caller: + .long trace_hardirqs_off_caller #endif #ifdef CONFIG_LOCKDEP .Llockdep_sys_exit: |
