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authorBernd Schmidt <bernds_cb1@t-online.de>2008-04-23 07:17:34 +0800
committerBryan Wu <cooloney@kernel.org>2008-04-23 07:17:34 +0800
commit2a0c4fdb6602ea066380aaf71ff7bb2f61ffeee8 (patch)
treeb77ed1db44e1d0948ac2ab8414066e365da21ddd
parentdbfe44f02b6855efb5a596e942ec2fd96d592f60 (diff)
[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>
-rw-r--r--arch/blackfin/mach-common/entry.S7
-rw-r--r--include/asm-blackfin/trace.h4
2 files changed, 8 insertions, 3 deletions
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index cee54cebbc6..a504c65d999 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -121,10 +121,14 @@ ENTRY(_ex_icplb_miss)
(R7:6,P5:4) = [sp++];
ASTAT = [sp++];
SAVE_ALL_SYS
- DEBUG_HWTRACE_SAVE(p5, r7)
#ifdef CONFIG_MPU
+ /* We must load R1 here, _before_ DEBUG_HWTRACE_SAVE, since that
+ * will change the stack pointer. */
R0 = SEQSTAT;
R1 = SP;
+#endif
+ DEBUG_HWTRACE_SAVE(p5, r7)
+#ifdef CONFIG_MPU
sp += -12;
call _cplb_hdr;
sp += 12;
@@ -191,6 +195,7 @@ ENTRY(_bfin_return_from_exception)
ENDPROC(_bfin_return_from_exception)
ENTRY(_handle_bad_cplb)
+ DEBUG_HWTRACE_RESTORE(p5, r7)
/* To get here, we just tried and failed to change a CPLB
* so, handle things in trap_c (C code), by lowering to
* IRQ5, just like we normally do. Since this is not a
diff --git a/include/asm-blackfin/trace.h b/include/asm-blackfin/trace.h
index ef18afbc210..312b596b973 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 */