[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>
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 @@
#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 @@
.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:
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index d7ce150..41aca06 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -61,19 +61,22 @@
#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