[Blackfin] arch: fix bug - when using trace buffer with CONFIG_MPU enabled.
There were a couple of problems with the way the trace buffer state
is saved/restored in assembly. The DEBUG_HWTRACE_SAVE/RESTORE macros
save a value to the stack, which is not immediately obvious; the CPLB
exception code needed changes to load the correct value of the stack
pointer. The other problem is that the SAVE/RESTORE macros weren't
pushing and popping the value downwards on the stack, but rather moving
it _upwards_, which is of course completely broken.
We also need to make sure there's a matching DEBUG_HWTRACE_RESTORE in
the error case of the CPLB handler.
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
diff --git a/include/asm-blackfin/trace.h b/include/asm-blackfin/trace.h
index ef18afb..312b596 100644
--- a/include/asm-blackfin/trace.h
+++ b/include/asm-blackfin/trace.h
@@ -62,14 +62,14 @@
preg.L = LO(TBUFCTL); \
preg.H = HI(TBUFCTL); \
dreg = [preg]; \
- [sp++] = dreg; \
+ [--sp] = dreg; \
dreg = 0x1; \
[preg] = dreg;
#define trace_buffer_restore(preg, dreg) \
preg.L = LO(TBUFCTL); \
preg.H = HI(TBUFCTL); \
- dreg = [sp--]; \
+ dreg = [sp++]; \
[preg] = dreg;
#else /* CONFIG_DEBUG_BFIN_HWTRACE_ON */