Commit 50bec4ce authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky

[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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 632448f6
......@@ -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:
......
......@@ -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
......
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