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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 /arch/blackfin/mach-common
parentdbfe44f02b6855efb5a596e942ec2fd96d592f60 (diff)
downloadop-kernel-dev-2a0c4fdb6602ea066380aaf71ff7bb2f61ffeee8.zip
op-kernel-dev-2a0c4fdb6602ea066380aaf71ff7bb2f61ffeee8.tar.gz
[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>
Diffstat (limited to 'arch/blackfin/mach-common')
-rw-r--r--arch/blackfin/mach-common/entry.S7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index cee54ce..a504c65 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
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