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[Blackfin] arch: fix bug - when using trace buffer with CONFIG_MPU enabled.

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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>
This commit is contained in:
Bernd Schmidt 2008-04-23 07:17:34 +08:00 committed by Bryan Wu
parent dbfe44f02b
commit 2a0c4fdb66
2 changed files with 8 additions and 3 deletions
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7
arch/blackfin/mach-common/entry.S
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@ -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

4
include/asm-blackfin/trace.h
View File

@ -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 */