diff options
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 127 |
1 files changed, 123 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 4dd38f129153..3cadba60a4b6 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -191,11 +191,49 @@ transfer_to_handler_cont: mflr r9 lwz r11,0(r9) /* virtual address of handler */ lwz r9,4(r9) /* where to go when done */ +#ifdef CONFIG_TRACE_IRQFLAGS + lis r12,reenable_mmu@h + ori r12,r12,reenable_mmu@l + mtspr SPRN_SRR0,r12 + mtspr SPRN_SRR1,r10 + SYNC + RFI +reenable_mmu: /* re-enable mmu so we can */ + mfmsr r10 + lwz r12,_MSR(r1) + xor r10,r10,r12 + andi. r10,r10,MSR_EE /* Did EE change? */ + beq 1f + + /* Save handler and return address into the 2 unused words + * of the STACK_FRAME_OVERHEAD (sneak sneak sneak). Everything + * else can be recovered from the pt_regs except r3 which for + * normal interrupts has been set to pt_regs and for syscalls + * is an argument, so we temporarily use ORIG_GPR3 to save it + */ + stw r9,8(r1) + stw r11,12(r1) + stw r3,ORIG_GPR3(r1) + bl trace_hardirqs_off + lwz r0,GPR0(r1) + lwz r3,ORIG_GPR3(r1) + lwz r4,GPR4(r1) + lwz r5,GPR5(r1) + lwz r6,GPR6(r1) + lwz r7,GPR7(r1) + lwz r8,GPR8(r1) + lwz r9,8(r1) + lwz r11,12(r1) +1: mtctr r11 + mtlr r9 + bctr /* jump to handler */ +#else /* CONFIG_TRACE_IRQFLAGS */ mtspr SPRN_SRR0,r11 mtspr SPRN_SRR1,r10 mtlr r9 SYNC RFI /* jump to handler, enable MMU */ +#endif /* CONFIG_TRACE_IRQFLAGS */ #if defined (CONFIG_6xx) || defined(CONFIG_E500) 4: rlwinm r12,r12,0,~_TLF_NAPPING @@ -251,6 +289,31 @@ _GLOBAL(DoSyscall) #ifdef SHOW_SYSCALLS bl do_show_syscall #endif /* SHOW_SYSCALLS */ +#ifdef CONFIG_TRACE_IRQFLAGS + /* Return from syscalls can (and generally will) hard enable + * interrupts. You aren't supposed to call a syscall with + * interrupts disabled in the first place. However, to ensure + * that we get it right vs. lockdep if it happens, we force + * that hard enable here with appropriate tracing if we see + * that we have been called with interrupts off + */ + mfmsr r11 + andi. r12,r11,MSR_EE + bne+ 1f + /* We came in with interrupts disabled, we enable them now */ + bl trace_hardirqs_on + mfmsr r11 + lwz r0,GPR0(r1) + lwz r3,GPR3(r1) + lwz r4,GPR4(r1) + ori r11,r11,MSR_EE + lwz r5,GPR5(r1) + lwz r6,GPR6(r1) + lwz r7,GPR7(r1) + lwz r8,GPR8(r1) + mtmsr r11 +1: +#endif /* CONFIG_TRACE_IRQFLAGS */ rlwinm r10,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ lwz r11,TI_FLAGS(r10) andi. r11,r11,_TIF_SYSCALL_T_OR_A @@ -275,6 +338,7 @@ ret_from_syscall: rlwinm r12,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ /* disable interrupts so current_thread_info()->flags can't change */ LOAD_MSR_KERNEL(r10,MSR_KERNEL) /* doesn't include MSR_EE */ + /* Note: We don't bother telling lockdep about it */ SYNC MTMSRD(r10) lwz r9,TI_FLAGS(r12) @@ -288,6 +352,19 @@ ret_from_syscall: oris r11,r11,0x1000 /* Set SO bit in CR */ stw r11,_CCR(r1) syscall_exit_cont: + lwz r8,_MSR(r1) +#ifdef CONFIG_TRACE_IRQFLAGS + /* If we are going to return from the syscall with interrupts + * off, we trace that here. It shouldn't happen though but we + * want to catch the bugger if it does right ? + */ + andi. r10,r8,MSR_EE + bne+ 1f + stw r3,GPR3(r1) + bl trace_hardirqs_off + lwz r3,GPR3(r1) +1: +#endif /* CONFIG_TRACE_IRQFLAGS */ #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* If the process has its own DBCR0 value, load it up. The internal debug mode bit tells us that dbcr0 should be loaded. */ @@ -311,7 +388,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) mtlr r4 mtcr r5 lwz r7,_NIP(r1) - lwz r8,_MSR(r1) FIX_SRR1(r8, r0) lwz r2,GPR2(r1) lwz r1,GPR1(r1) @@ -394,7 +470,9 @@ syscall_exit_work: andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP) beq ret_from_except - /* Re-enable interrupts */ + /* Re-enable interrupts. There is no need to trace that with + * lockdep as we are supposed to have IRQs on at this point + */ ori r10,r10,MSR_EE SYNC MTMSRD(r10) @@ -705,6 +783,7 @@ ret_from_except: /* Hard-disable interrupts so that current_thread_info()->flags * can't change between when we test it and when we return * from the interrupt. */ + /* Note: We don't bother telling lockdep about it */ LOAD_MSR_KERNEL(r10,MSR_KERNEL) SYNC /* Some chip revs have problems here... */ MTMSRD(r10) /* disable interrupts */ @@ -744,11 +823,24 @@ resume_kernel: beq+ restore andi. r0,r3,MSR_EE /* interrupts off? */ beq restore /* don't schedule if so */ +#ifdef CONFIG_TRACE_IRQFLAGS + /* Lockdep thinks irqs are enabled, we need to call + * preempt_schedule_irq with IRQs off, so we inform lockdep + * now that we -did- turn them off already + */ + bl trace_hardirqs_off +#endif 1: bl preempt_schedule_irq rlwinm r9,r1,0,0,(31-THREAD_SHIFT) lwz r3,TI_FLAGS(r9) andi. r0,r3,_TIF_NEED_RESCHED bne- 1b +#ifdef CONFIG_TRACE_IRQFLAGS + /* And now, to properly rebalance the above, we tell lockdep they + * are being turned back on, which will happen when we return + */ + bl trace_hardirqs_on +#endif #else resume_kernel: #endif /* CONFIG_PREEMPT */ @@ -765,6 +857,28 @@ restore: stw r6,icache_44x_need_flush@l(r4) 1: #endif /* CONFIG_44x */ + + lwz r9,_MSR(r1) +#ifdef CONFIG_TRACE_IRQFLAGS + /* Lockdep doesn't know about the fact that IRQs are temporarily turned + * off in this assembly code while peeking at TI_FLAGS() and such. However + * we need to inform it if the exception turned interrupts off, and we + * are about to trun them back on. + * + * The problem here sadly is that we don't know whether the exceptions was + * one that turned interrupts off or not. So we always tell lockdep about + * turning them on here when we go back to wherever we came from with EE + * on, even if that may meen some redudant calls being tracked. Maybe later + * we could encode what the exception did somewhere or test the exception + * type in the pt_regs but that sounds overkill + */ + andi. r10,r9,MSR_EE + beq 1f + bl trace_hardirqs_on + lwz r9,_MSR(r1) +1: +#endif /* CONFIG_TRACE_IRQFLAGS */ + lwz r0,GPR0(r1) lwz r2,GPR2(r1) REST_4GPRS(3, r1) @@ -782,7 +896,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) stwcx. r0,0,r1 /* to clear the reservation */ #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE)) - lwz r9,_MSR(r1) andi. r10,r9,MSR_RI /* check if this exception occurred */ beql nonrecoverable /* at a bad place (MSR:RI = 0) */ @@ -805,7 +918,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) MTMSRD(r10) /* clear the RI bit */ .globl exc_exit_restart exc_exit_restart: - lwz r9,_MSR(r1) lwz r12,_NIP(r1) FIX_SRR1(r9,r10) mtspr SPRN_SRR0,r12 @@ -1035,11 +1147,18 @@ do_work: /* r10 contains MSR_KERNEL here */ beq do_user_signal do_resched: /* r10 contains MSR_KERNEL here */ + /* Note: We don't need to inform lockdep that we are enabling + * interrupts here. As far as it knows, they are already enabled + */ ori r10,r10,MSR_EE SYNC MTMSRD(r10) /* hard-enable interrupts */ bl schedule recheck: + /* Note: And we don't tell it we are disabling them again + * neither. Those disable/enable cycles used to peek at + * TI_FLAGS aren't advertised. + */ LOAD_MSR_KERNEL(r10,MSR_KERNEL) SYNC MTMSRD(r10) /* disable interrupts */ |
