[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>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-blackfin/trace.h b/include/asm-blackfin/trace.h
index ef18afbc2101..312b596b9731 100644
--- a/include/asm-blackfin/trace.h
+++ b/include/asm-blackfin/trace.h
@@ -62,14 +62,14 @@ extern unsigned long software_trace_buff[];
         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 */