ret_from_except)
-/* Check for a single step debug exception while in an exception
- * handler before state has been saved. This is to catch the case
- * where an instruction that we are trying to single step causes
- * an exception (eg ITLB/DTLB miss) and thus the first instruction of
- * the exception handler generates a single step debug exception.
- *
- * If we get a debug trap on the first instruction of an exception handler,
- * we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
- * a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
- * The exception handler was handling a non-critical interrupt, so it will
- * save (and later restore) the MSR via SPRN_CSRR1, which will still have
- * the MSR_DE bit set.
- */
-#define DEBUG_EXCEPTION \
- START_EXCEPTION(Debug); \
- CRITICAL_EXCEPTION_PROLOG; \
- \
- /* \
- * If there is a single step or branch-taken exception in an \
- * exception entry sequence, it was probably meant to apply to \
- * the code where the exception occurred (since exception entry \
- * doesn't turn off DE automatically). We simulate the effect \
- * of turning off DE on entry to an exception handler by turning \
- * off DE in the CSRR1 value and clearing the debug status. \
- */ \
- mfspr r10,SPRN_DBSR; /* check single-step/branch taken */ \
- andis. r10,r10,DBSR_IC@h; \
- beq+ 2f; \
- \
- lis r10,KERNELBASE@h; /* check if exception in vectors */ \
- ori r10,r10,KERNELBASE@l; \
- cmplw r12,r10; \
- blt+ 2f; /* addr below exception vectors */ \
- \
- lis r10,Debug@h; \
- ori r10,r10,Debug@l; \
- cmplw r12,r10; \
- bgt+ 2f; /* addr above exception vectors */ \
- \
- /* here it looks like we got an inappropriate debug exception. */ \
-1: rlwinm r9,r9,0,~MSR_DE; /* clear DE in the CSRR1 value */ \
- lis r10,DBSR_IC@h; /* clear the IC event */ \
- mtspr SPRN_DBSR,r10; \
- /* restore state and get out */ \
- lwz r10,_CCR(r11); \
- lwz r0,GPR0(r11); \
- lwz r1,GPR1(r11); \
- mtcrf 0x80,r10; \
- mtspr CSRR0,r12; \
- mtspr CSRR1,r9; \
- lwz r9,GPR9(r11); \
- lwz r12,GPR12(r11); \
- mtspr SPRG2,r8; /* SPRG2 only used in criticals */ \
- lis r8,crit_save@ha; \
- lwz r10,crit_r10@l(r8); \
- lwz r11,crit_r11@l(r8); \
- mfspr r8,SPRG2; \
- \
- rfci; \
- b .; \
- \
- /* continue normal handling for a critical exception... */ \
-2: mfspr r4,SPRN_DBSR; \
- addi r3,r1,STACK_FRAME_OVERHEAD; \
- EXC_XFER_TEMPLATE(DebugException, 0x2002, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
-
#endif /* __HEAD_BOOKE_H__ */
git://git.onelab.eu / linux-2.6.git / blobdiff