aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/include
diff options
context:
space:
mode:
authorVasily Gorbik <gor@linux.ibm.com>2019-11-22 12:47:52 +0100
committerVasily Gorbik <gor@linux.ibm.com>2019-11-30 10:52:45 +0100
commit7579425777c0d802237e0d59ae395e8cf60723e1 (patch)
tree078c05f1f27abf642cfc33b6987ff7cadd39266a /arch/s390/include
parent103b4cca60d2c8c51f1290cc984b7046ccb8b46d (diff)
s390: correct CALL_ON_STACK back_chain saving
Currently CALL_ON_STACK saves r15 as back_chain in the first stack frame of the stack we about to switch to. But if a function which uses CALL_ON_STACK calls other function it allocates a stack frame for a callee. In this case r15 is pointing to a callee stack frame and not a stack frame of function itself. This results in dummy unwinding entry with random sp and ip values. Introduce and utilize current_frame_address macro to get an address of actual function stack frame. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/include')
-rw-r--r--arch/s390/include/asm/stacktrace.h15
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
index 0ae4bbf7779c..bb854e33e460 100644
--- a/arch/s390/include/asm/stacktrace.h
+++ b/arch/s390/include/asm/stacktrace.h
@@ -62,6 +62,17 @@ struct stack_frame {
};
#endif
+/*
+ * Unlike current_stack_pointer() which simply returns current value of %r15
+ * current_frame_address() returns function stack frame address, which matches
+ * %r15 upon function invocation. It may differ from %r15 later if function
+ * allocates stack for local variables or new stack frame to call other
+ * functions.
+ */
+#define current_frame_address() \
+ ((unsigned long)__builtin_frame_address(0) - \
+ offsetof(struct stack_frame, back_chain))
+
#define CALL_ARGS_0() \
register unsigned long r2 asm("2")
#define CALL_ARGS_1(arg1) \
@@ -95,18 +106,20 @@ struct stack_frame {
#define CALL_ON_STACK(fn, stack, nr, args...) \
({ \
+ unsigned long frame = current_frame_address(); \
CALL_ARGS_##nr(args); \
unsigned long prev; \
\
asm volatile( \
" la %[_prev],0(15)\n" \
" la 15,0(%[_stack])\n" \
- " stg %[_prev],%[_bc](15)\n" \
+ " stg %[_frame],%[_bc](15)\n" \
" brasl 14,%[_fn]\n" \
" la 15,0(%[_prev])\n" \
: [_prev] "=&a" (prev), CALL_FMT_##nr \
[_stack] "a" (stack), \
[_bc] "i" (offsetof(struct stack_frame, back_chain)), \
+ [_frame] "d" (frame), \
[_fn] "X" (fn) : CALL_CLOBBER_##nr); \
r2; \
})

Privacy Policy