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[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>
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parent
dbfe44f02b
commit
2a0c4fdb66
2 changed files with 8 additions and 3 deletions
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@ -121,10 +121,14 @@ ENTRY(_ex_icplb_miss)
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(R7:6,P5:4) = [sp++];
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ASTAT = [sp++];
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SAVE_ALL_SYS
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DEBUG_HWTRACE_SAVE(p5, r7)
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#ifdef CONFIG_MPU
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/* We must load R1 here, _before_ DEBUG_HWTRACE_SAVE, since that
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* will change the stack pointer. */
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R0 = SEQSTAT;
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R1 = SP;
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#endif
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DEBUG_HWTRACE_SAVE(p5, r7)
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#ifdef CONFIG_MPU
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sp += -12;
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call _cplb_hdr;
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sp += 12;
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@ -191,6 +195,7 @@ ENTRY(_bfin_return_from_exception)
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ENDPROC(_bfin_return_from_exception)
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ENTRY(_handle_bad_cplb)
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DEBUG_HWTRACE_RESTORE(p5, r7)
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/* To get here, we just tried and failed to change a CPLB
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* so, handle things in trap_c (C code), by lowering to
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* IRQ5, just like we normally do. Since this is not a
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@ -62,14 +62,14 @@ extern unsigned long software_trace_buff[];
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preg.L = LO(TBUFCTL); \
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preg.H = HI(TBUFCTL); \
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dreg = [preg]; \
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[sp++] = dreg; \
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[--sp] = dreg; \
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dreg = 0x1; \
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[preg] = dreg;
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#define trace_buffer_restore(preg, dreg) \
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preg.L = LO(TBUFCTL); \
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preg.H = HI(TBUFCTL); \
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dreg = [sp--]; \
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dreg = [sp++]; \
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[preg] = dreg;
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#else /* CONFIG_DEBUG_BFIN_HWTRACE_ON */
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