diff options
Diffstat (limited to 'arch/blackfin/mach-common/entry.S')
| -rw-r--r-- | arch/blackfin/mach-common/entry.S | 108 |
1 files changed, 77 insertions, 31 deletions
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S index 7365a17..038f70e 100644 --- a/arch/blackfin/mach-common/entry.S +++ b/arch/blackfin/mach-common/entry.S @@ -151,26 +151,62 @@ ENTRY(_ex_soft_bp) ENDPROC(_ex_soft_bp) ENTRY(_ex_single_step) + /* If we just returned from an interrupt, the single step event is + for the RTI instruction. */ r7 = retx; r6 = reti; cc = r7 == r6; - if cc jump _bfin_return_from_exception - r7 = syscfg; - bitclr (r7, 0); - syscfg = R7; + if cc jump _bfin_return_from_exception; + /* If we were in user mode, do the single step normally. */ p5.l = lo(IPEND); p5.h = hi(IPEND); r6 = [p5]; - cc = bittst(r6, 5); - if !cc jump _ex_trap_c; - p4.l = lo(EVT5); - p4.h = hi(EVT5); - r6.h = _exception_to_level5; - r6.l = _exception_to_level5; - r7 = [p4]; - cc = r6 == r7; - if !cc jump _ex_trap_c; + r7 = 0xffe0 (z); + r7 = r7 & r6; + cc = r7 == 0; + if !cc jump 1f; + + /* Single stepping only a single instruction, so clear the trace + * bit here. */ + r7 = syscfg; + bitclr (r7, 0); + syscfg = R7; + jump _ex_trap_c; + +1: + /* + * We were in an interrupt handler. By convention, all of them save + * SYSCFG with their first instruction, so by checking whether our + * RETX points at the entry point, we can determine whether to allow + * a single step, or whether to clear SYSCFG. + * + * First, find out the interrupt level and the event vector for it. + */ + p5.l = lo(EVT0); + p5.h = hi(EVT0); + p5 += -4; +2: + r7 = rot r7 by -1; + p5 += 4; + if !cc jump 2b; + + /* What we actually do is test for the _second_ instruction in the + * IRQ handler. That way, if there are insns following the restore + * of SYSCFG after leaving the handler, we will not turn off SYSCFG + * for them. */ + + r7 = [p5]; + r7 += 2; + r6 = RETX; + cc = R7 == R6; + if !cc jump _bfin_return_from_exception; + + r7 = syscfg; + bitclr (r7, 0); + syscfg = R7; + + /* Fall through to _bfin_return_from_exception. */ ENDPROC(_ex_single_step) ENTRY(_bfin_return_from_exception) @@ -234,20 +270,26 @@ ENTRY(_ex_trap_c) p5.l = _saved_icplb_fault_addr; [p5] = r7; - p4.l = __retx; - p4.h = __retx; + p4.l = _excpt_saved_stuff; + p4.h = _excpt_saved_stuff; + r6 = retx; [p4] = r6; - p4.l = lo(SAFE_USER_INSTRUCTION); - p4.h = hi(SAFE_USER_INSTRUCTION); - retx = p4; + + r6 = SYSCFG; + [p4 + 4] = r6; + BITCLR(r6, 0); + SYSCFG = r6; /* Disable all interrupts, but make sure level 5 is enabled so * we can switch to that level. Save the old mask. */ cli r6; - p4.l = _excpt_saved_imask; - p4.h = _excpt_saved_imask; - [p4] = r6; + [p4 + 8] = r6; + + p4.l = lo(SAFE_USER_INSTRUCTION); + p4.h = hi(SAFE_USER_INSTRUCTION); + retx = p4; + r6 = 0x3f; sti r6; @@ -312,16 +354,17 @@ ENDPROC(_double_fault) ENTRY(_exception_to_level5) SAVE_ALL_SYS - p4.l = __retx; - p4.h = __retx; + p4.l = _excpt_saved_stuff; + p4.h = _excpt_saved_stuff; r6 = [p4]; [sp + PT_PC] = r6; + r6 = [p4 + 4]; + [sp + PT_SYSCFG] = r6; + /* Restore interrupt mask. We haven't pushed RETI, so this * doesn't enable interrupts until we return from this handler. */ - p4.l = _excpt_saved_imask; - p4.h = _excpt_saved_imask; - r6 = [p4]; + r6 = [p4 + 8]; sti r6; /* Restore the hardware error vector. */ @@ -1349,7 +1392,14 @@ ENTRY(_sys_call_table) .rept NR_syscalls-(.-_sys_call_table)/4 .long _sys_ni_syscall .endr -_excpt_saved_imask: + + /* + * Used to save the real RETX, IMASK and SYSCFG when temporarily + * storing safe values across the transition from exception to IRQ5. + */ +_excpt_saved_stuff: + .long 0; + .long 0; .long 0; _exception_stack: @@ -1363,7 +1413,3 @@ _exception_stack_top: _last_cplb_fault_retx: .long 0; #endif - /* Used to save the real RETX when temporarily storing a safe - * return address. */ -__retx: - .long 0; |
