diff options
Diffstat (limited to 'arch/xtensa/kernel/entry.S')
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 72 |
1 files changed, 71 insertions, 1 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index ab7904fd027f..fe8f7e7efb9d 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -543,6 +543,12 @@ common_exception_return: #endif 5: +#ifdef CONFIG_HAVE_HW_BREAKPOINT + _bbci.l a4, TIF_DB_DISABLED, 7f + movi a4, restore_dbreak + callx4 a4 +7: +#endif #ifdef CONFIG_DEBUG_TLB_SANITY l32i a4, a1, PT_DEPC bgeui a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f @@ -808,6 +814,18 @@ ENTRY(debug_exception) s32i a0, a2, PT_AREG2 mov a1, a2 + /* Debug exception is handled as an exception, so interrupts will + * likely be enabled in the common exception handler. Disable + * preemption if we have HW breakpoints to preserve DEBUGCAUSE.DBNUM + * meaning. + */ +#if defined(CONFIG_PREEMPT_COUNT) && defined(CONFIG_HAVE_HW_BREAKPOINT) + GET_THREAD_INFO(a2, a1) + l32i a3, a2, TI_PRE_COUNT + addi a3, a3, 1 + s32i a3, a2, TI_PRE_COUNT +#endif + rsr a2, ps bbsi.l a2, PS_UM_BIT, _user_exception j _kernel_exception @@ -816,8 +834,60 @@ ENTRY(debug_exception) l32i a2, a2, EXC_TABLE_KSTK # load kernel stack pointer j 3b - /* Debug exception while in exception mode. */ +#ifdef CONFIG_HAVE_HW_BREAKPOINT + /* Debug exception while in exception mode. This may happen when + * window overflow/underflow handler or fast exception handler hits + * data breakpoint, in which case save and disable all data + * breakpoints, single-step faulting instruction and restore data + * breakpoints. + */ +1: + bbci.l a0, PS_UM_BIT, 1b # jump if kernel mode + + rsr a0, debugcause + bbsi.l a0, DEBUGCAUSE_DBREAK_BIT, .Ldebug_save_dbreak + + .set _index, 0 + .rept XCHAL_NUM_DBREAK + l32i a0, a3, DT_DBREAKC_SAVE + _index * 4 + wsr a0, SREG_DBREAKC + _index + .set _index, _index + 1 + .endr + + l32i a0, a3, DT_ICOUNT_LEVEL_SAVE + wsr a0, icountlevel + + l32i a0, a3, DT_ICOUNT_SAVE + xsr a0, icount + + l32i a0, a3, DT_DEBUG_SAVE + xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL + rfi XCHAL_DEBUGLEVEL + +.Ldebug_save_dbreak: + .set _index, 0 + .rept XCHAL_NUM_DBREAK + movi a0, 0 + xsr a0, SREG_DBREAKC + _index + s32i a0, a3, DT_DBREAKC_SAVE + _index * 4 + .set _index, _index + 1 + .endr + + movi a0, XCHAL_EXCM_LEVEL + 1 + xsr a0, icountlevel + s32i a0, a3, DT_ICOUNT_LEVEL_SAVE + + movi a0, 0xfffffffe + xsr a0, icount + s32i a0, a3, DT_ICOUNT_SAVE + + l32i a0, a3, DT_DEBUG_SAVE + xsr a3, SREG_EXCSAVE + XCHAL_DEBUGLEVEL + rfi XCHAL_DEBUGLEVEL +#else + /* Debug exception while in exception mode. Should not happen. */ 1: j 1b // FIXME!! +#endif ENDPROC(debug_exception) |