diff options
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 116 |
1 files changed, 67 insertions, 49 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index d0cea3deb86c..0c555f9f1543 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -37,6 +37,7 @@ #include <asm/feature-fixups.h> #include <asm/barrier.h> #include <asm/kup.h> +#include <asm/bug.h> #include "head_32.h" @@ -206,19 +207,42 @@ transfer_to_handler_cont: mtspr SPRN_NRI, r0 #endif #ifdef CONFIG_TRACE_IRQFLAGS + /* + * When tracing IRQ state (lockdep) we enable the MMU before we call + * the IRQ tracing functions as they might access vmalloc space or + * perform IOs for console output. + * + * To speed up the syscall path where interrupts stay on, let's check + * first if we are changing the MSR value at all. + */ + tophys(r12, r1) + lwz r12,_MSR(r12) + xor r12,r10,r12 + andi. r12,r12,MSR_EE + bne 1f + + /* MSR isn't changing, just transition directly */ +#endif + mtspr SPRN_SRR0,r11 + mtspr SPRN_SRR1,r10 + mtlr r9 + SYNC + RFI /* jump to handler, enable MMU */ + +#ifdef CONFIG_TRACE_IRQFLAGS +1: /* MSR is changing, re-enable MMU so we can notify lockdep. We need to + * keep interrupts disabled at this point otherwise we might risk + * taking an interrupt before we tell lockdep they are enabled. + */ lis r12,reenable_mmu@h ori r12,r12,reenable_mmu@l + LOAD_MSR_KERNEL(r0, MSR_KERNEL) mtspr SPRN_SRR0,r12 - mtspr SPRN_SRR1,r10 + mtspr SPRN_SRR1,r0 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 +reenable_mmu: /* * The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. * If from user mode there is only one stack frame on the stack, and @@ -233,14 +257,24 @@ reenable_mmu: /* re-enable mmu so we can */ * they aren't useful past this point (aren't syscall arguments), * the rest is restored from the exception frame. */ + + /* Are we enabling or disabling interrupts ? */ + andi. r0,r10,MSR_EE + stwu r1,-32(r1) stw r9,8(r1) stw r11,12(r1) stw r3,16(r1) stw r4,20(r1) stw r5,24(r1) - bl trace_hardirqs_off - lwz r5,24(r1) + + bne- 0f + + /* If we are disabling interrupts (normal case), simply log it with + * lockdep + */ +1: bl trace_hardirqs_off +2: lwz r5,24(r1) lwz r4,20(r1) lwz r3,16(r1) lwz r11,12(r1) @@ -250,15 +284,22 @@ reenable_mmu: /* re-enable mmu so we can */ lwz r6,GPR6(r1) lwz r7,GPR7(r1) lwz r8,GPR8(r1) -1: mtctr r11 + 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 */ + + /* If we are enabling interrupt, this is a syscall. They shouldn't + * happen while interrupts are disabled, so let's do a warning here. + */ +0: trap + EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING + bl trace_hardirqs_on + + /* Now enable for real */ + mfmsr r10 + ori r10,r10,MSR_EE + mtmsr r10 + b 2b #endif /* CONFIG_TRACE_IRQFLAGS */ #if defined (CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500) @@ -316,29 +357,13 @@ _GLOBAL(DoSyscall) rlwinm r11,r11,0,4,2 stw r11,_CCR(r1) #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 - */ + /* Make sure interrupts are enabled */ 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: + /* We came in with interrupts disabled, we WARN and mark them enabled + * for lockdep now */ +0: tweqi r12, 0 + EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING #endif /* CONFIG_TRACE_IRQFLAGS */ lwz r11,TI_FLAGS(r2) andi. r11,r11,_TIF_SYSCALL_DOTRACE @@ -392,8 +417,7 @@ 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 ? + * off, we trace that here. It shouldn't normally happen. */ andi. r10,r8,MSR_EE bne+ 1f @@ -918,13 +942,6 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x) * 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 @@ -1212,9 +1229,10 @@ 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 - */ +#ifdef CONFIG_TRACE_IRQFLAGS + bl trace_hardirqs_on + mfmsr r10 +#endif ori r10,r10,MSR_EE SYNC MTMSRD(r10) /* hard-enable interrupts */ |