From 7230c5644188cd9e3fb380cc97dde00c464a3ba7 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 6 Mar 2012 18:27:59 +1100 Subject: [PATCH] powerpc: Rework lazy-interrupt handling The current implementation of lazy interrupts handling has some issues that this tries to address. We don't do the various workarounds we need to do when re-enabling interrupts in some cases such as when returning from an interrupt and thus we may still lose or get delayed decrementer or doorbell interrupts. The current scheme also makes it much harder to handle the external "edge" interrupts provided by some BookE processors when using the EPR facility (External Proxy) and the Freescale Hypervisor. Additionally, we tend to keep interrupts hard disabled in a number of cases, such as decrementer interrupts, external interrupts, or when a masked decrementer interrupt is pending. This is sub-optimal. This is an attempt at fixing it all in one go by reworking the way we do the lazy interrupt disabling from the ground up. The base idea is to replace the "hard_enabled" field with a "irq_happened" field in which we store a bit mask of what interrupt occurred while soft-disabled. When re-enabling, either via arch_local_irq_restore() or when returning from an interrupt, we can now decide what to do by testing bits in that field. We then implement replaying of the missed interrupts either by re-using the existing exception frame (in exception exit case) or via the creation of a new one from an assembly trampoline (in the arch_local_irq_enable case). This removes the need to play with the decrementer to try to create fake interrupts, among others. In addition, this adds a few refinements: - We no longer hard disable decrementer interrupts that occur while soft-disabled. We now simply bump the decrementer back to max (on BookS) or leave it stopped (on BookE) and continue with hard interrupts enabled, which means that we'll potentially get better sample quality from performance monitor interrupts. - Timer, decrementer and doorbell interrupts now hard-enable shortly after removing the source of the interrupt, which means they no longer run entirely hard disabled. Again, this will improve perf sample quality. - On Book3E 64-bit, we now make the performance monitor interrupt act as an NMI like Book3S (the necessary C code for that to work appear to already be present in the FSL perf code, notably calling nmi_enter instead of irq_enter). (This also fixes a bug where BookE perfmon interrupts could clobber r14 ... oops) - We could make "masked" decrementer interrupts act as NMIs when doing timer-based perf sampling to improve the sample quality. Signed-off-by-yet: Benjamin Herrenschmidt --- v2: - Add hard-enable to decrementer, timer and doorbells - Fix CR clobber in masked irq handling on BookE - Make embedded perf interrupt act as an NMI - Add a PACA_HAPPENED_EE_EDGE for use by FSL if they want to retrigger an interrupt without preventing hard-enable v3: - Fix or vs. ori bug on Book3E - Fix enabling of interrupts for some exceptions on Book3E v4: - Fix resend of doorbells on return from interrupt on Book3E v5: - Rebased on top of my latest series, which involves some significant rework of some aspects of the patch. v6: - 32-bit compile fix - more compile fixes with various .config combos - factor out the asm code to soft-disable interrupts - remove the C wrapper around preempt_schedule_irq v7: - Fix a bug with hard irq state tracking on native power7 --- arch/powerpc/include/asm/exception-64s.h | 34 ++- arch/powerpc/include/asm/hw_irq.h | 49 +++- arch/powerpc/include/asm/irqflags.h | 37 +-- arch/powerpc/include/asm/paca.h | 2 +- arch/powerpc/kernel/asm-offsets.c | 2 +- arch/powerpc/kernel/dbell.c | 2 + arch/powerpc/kernel/entry_64.S | 153 +++++++++--- arch/powerpc/kernel/exceptions-64e.S | 221 ++++++++++++------ arch/powerpc/kernel/exceptions-64s.S | 150 +++++------- arch/powerpc/kernel/head_64.S | 24 +- arch/powerpc/kernel/idle.c | 6 +- arch/powerpc/kernel/idle_book3e.S | 25 +- arch/powerpc/kernel/idle_power4.S | 24 +- arch/powerpc/kernel/idle_power7.S | 23 +- arch/powerpc/kernel/irq.c | 204 +++++++++++----- arch/powerpc/kernel/process.c | 3 + arch/powerpc/kernel/time.c | 8 +- .../platforms/pseries/processor_idle.c | 18 +- arch/powerpc/xmon/xmon.c | 4 +- 19 files changed, 647 insertions(+), 342 deletions(-) diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 70354af0740e..548da3aa0a30 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -232,23 +232,30 @@ label##_hv: \ EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common, \ EXC_HV, KVMTEST, vec) -#define __SOFTEN_TEST(h) \ +/* This associate vector numbers with bits in paca->irq_happened */ +#define SOFTEN_VALUE_0x500 PACA_IRQ_EE +#define SOFTEN_VALUE_0x502 PACA_IRQ_EE +#define SOFTEN_VALUE_0x900 PACA_IRQ_DEC +#define SOFTEN_VALUE_0x982 PACA_IRQ_DEC + +#define __SOFTEN_TEST(h, vec) \ lbz r10,PACASOFTIRQEN(r13); \ cmpwi r10,0; \ + li r10,SOFTEN_VALUE_##vec; \ beq masked_##h##interrupt -#define _SOFTEN_TEST(h) __SOFTEN_TEST(h) +#define _SOFTEN_TEST(h, vec) __SOFTEN_TEST(h, vec) #define SOFTEN_TEST_PR(vec) \ KVMTEST_PR(vec); \ - _SOFTEN_TEST(EXC_STD) + _SOFTEN_TEST(EXC_STD, vec) #define SOFTEN_TEST_HV(vec) \ KVMTEST(vec); \ - _SOFTEN_TEST(EXC_HV) + _SOFTEN_TEST(EXC_HV, vec) #define SOFTEN_TEST_HV_201(vec) \ KVMTEST(vec); \ - _SOFTEN_TEST(EXC_STD) + _SOFTEN_TEST(EXC_STD, vec) #define __MASKABLE_EXCEPTION_PSERIES(vec, label, h, extra) \ HMT_MEDIUM; \ @@ -279,22 +286,7 @@ label##_hv: \ */ /* Exception addition: Hard disable interrupts */ -#ifdef CONFIG_TRACE_IRQFLAGS -#define DISABLE_INTS \ - lbz r10,PACASOFTIRQEN(r13); \ - li r11,0; \ - cmpwi cr0,r10,0; \ - stb r11,PACAHARDIRQEN(r13); \ - beq 44f; \ - stb r11,PACASOFTIRQEN(r13); \ - TRACE_DISABLE_INTS; \ -44: -#else -#define DISABLE_INTS \ - li r11,0; \ - stb r11,PACASOFTIRQEN(r13); \ - stb r11,PACAHARDIRQEN(r13) -#endif /* CONFIG_TRACE_IRQFLAGS */ +#define DISABLE_INTS SOFT_DISABLE_INTS(r10,r11) /* Exception addition: Keep interrupt state */ #define ENABLE_INTS \ diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index 6c6fa955baa7..51010bfc792e 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -11,6 +11,27 @@ #include #include +#ifdef CONFIG_PPC64 + +/* + * PACA flags in paca->irq_happened. + * + * This bits are set when interrupts occur while soft-disabled + * and allow a proper replay. Additionally, PACA_IRQ_HARD_DIS + * is set whenever we manually hard disable. + */ +#define PACA_IRQ_HARD_DIS 0x01 +#define PACA_IRQ_DBELL 0x02 +#define PACA_IRQ_EE 0x04 +#define PACA_IRQ_DEC 0x08 /* Or FIT */ +#define PACA_IRQ_EE_EDGE 0x10 /* BookE only */ + +#endif /* CONFIG_PPC64 */ + +#ifndef __ASSEMBLY__ + +extern void __replay_interrupt(unsigned int vector); + extern void timer_interrupt(struct pt_regs *); #ifdef CONFIG_PPC64 @@ -42,7 +63,6 @@ static inline unsigned long arch_local_irq_disable(void) } extern void arch_local_irq_restore(unsigned long); -extern void iseries_handle_interrupts(void); static inline void arch_local_irq_enable(void) { @@ -72,12 +92,24 @@ static inline bool arch_irqs_disabled(void) #define __hard_irq_disable() __mtmsrd(local_paca->kernel_msr, 1) #endif -#define hard_irq_disable() \ - do { \ - __hard_irq_disable(); \ - get_paca()->soft_enabled = 0; \ - get_paca()->hard_enabled = 0; \ - } while(0) +static inline void hard_irq_disable(void) +{ + __hard_irq_disable(); + get_paca()->soft_enabled = 0; + get_paca()->irq_happened |= PACA_IRQ_HARD_DIS; +} + +/* + * This is called by asynchronous interrupts to conditionally + * re-enable hard interrupts when soft-disabled after having + * cleared the source of the interrupt + */ +static inline void may_hard_irq_enable(void) +{ + get_paca()->irq_happened &= ~PACA_IRQ_HARD_DIS; + if (!(get_paca()->irq_happened & PACA_IRQ_EE)) + __hard_irq_enable(); +} static inline bool arch_irq_disabled_regs(struct pt_regs *regs) { @@ -149,6 +181,8 @@ static inline bool arch_irq_disabled_regs(struct pt_regs *regs) return !(regs->msr & MSR_EE); } +static inline void may_hard_irq_enable(void) { } + #endif /* CONFIG_PPC64 */ #define ARCH_IRQ_INIT_FLAGS IRQ_NOREQUEST @@ -159,5 +193,6 @@ static inline bool arch_irq_disabled_regs(struct pt_regs *regs) */ struct irq_chip; +#endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_HW_IRQ_H */ diff --git a/arch/powerpc/include/asm/irqflags.h b/arch/powerpc/include/asm/irqflags.h index b0b06d85788d..6f9b6e23dc5a 100644 --- a/arch/powerpc/include/asm/irqflags.h +++ b/arch/powerpc/include/asm/irqflags.h @@ -39,24 +39,31 @@ #define TRACE_ENABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on) #define TRACE_DISABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off) -#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) \ - cmpdi en,0; \ - bne 95f; \ - stb en,PACASOFTIRQEN(r13); \ - TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off) \ - b skip; \ -95: TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on) \ - li en,1; -#define TRACE_AND_RESTORE_IRQ(en) \ - TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f); \ - stb en,PACASOFTIRQEN(r13); \ -96: +/* + * This is used by assembly code to soft-disable interrupts + */ +#define SOFT_DISABLE_INTS(__rA, __rB) \ + lbz __rA,PACASOFTIRQEN(r13); \ + lbz __rB,PACAIRQHAPPENED(r13); \ + cmpwi cr0,__rA,0; \ + li __rA,0; \ + ori __rB,__rB,PACA_IRQ_HARD_DIS; \ + stb __rB,PACAIRQHAPPENED(r13); \ + beq 44f; \ + stb __rA,PACASOFTIRQEN(r13); \ + TRACE_DISABLE_INTS; \ +44: + #else #define TRACE_ENABLE_INTS #define TRACE_DISABLE_INTS -#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) -#define TRACE_AND_RESTORE_IRQ(en) \ - stb en,PACASOFTIRQEN(r13) + +#define SOFT_DISABLE_INTS(__rA, __rB) \ + lbz __rA,PACAIRQHAPPENED(r13); \ + li __rB,0; \ + ori __rA,__rA,PACA_IRQ_HARD_DIS; \ + stb __rB,PACASOFTIRQEN(r13); \ + stb __rA,PACAIRQHAPPENED(r13) #endif #endif diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 269c05a36d91..daf813fea91f 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -132,7 +132,7 @@ struct paca_struct { u64 saved_msr; /* MSR saved here by enter_rtas */ u16 trap_save; /* Used when bad stack is encountered */ u8 soft_enabled; /* irq soft-enable flag */ - u8 hard_enabled; /* set if irqs are enabled in MSR */ + u8 irq_happened; /* irq happened while soft-disabled */ u8 io_sync; /* writel() needs spin_unlock sync */ u8 irq_work_pending; /* IRQ_WORK interrupt while soft-disable */ u8 nap_state_lost; /* NV GPR values lost in power7_idle */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 04caee7d9bc1..cdd0d264415f 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -147,7 +147,7 @@ int main(void) DEFINE(PACAKBASE, offsetof(struct paca_struct, kernelbase)); DEFINE(PACAKMSR, offsetof(struct paca_struct, kernel_msr)); DEFINE(PACASOFTIRQEN, offsetof(struct paca_struct, soft_enabled)); - DEFINE(PACAHARDIRQEN, offsetof(struct paca_struct, hard_enabled)); + DEFINE(PACAIRQHAPPENED, offsetof(struct paca_struct, irq_happened)); DEFINE(PACACONTEXTID, offsetof(struct paca_struct, context.id)); #ifdef CONFIG_PPC_MM_SLICES DEFINE(PACALOWSLICESPSIZE, offsetof(struct paca_struct, diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c index 2cc451aaaca7..5b25c8060fd6 100644 --- a/arch/powerpc/kernel/dbell.c +++ b/arch/powerpc/kernel/dbell.c @@ -37,6 +37,8 @@ void doorbell_exception(struct pt_regs *regs) irq_enter(); + may_hard_irq_enable(); + smp_ipi_demux(); irq_exit(); diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index c513beb78b3b..f8a7a1a1a9f4 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -32,6 +32,7 @@ #include #include #include +#include /* * System calls. @@ -583,18 +584,72 @@ _GLOBAL(ret_from_except_lite) bne do_work #endif /* !CONFIG_PREEMPT */ + .globl fast_exc_return_irq +fast_exc_return_irq: restore: + /* + * This is the main kernel exit path, we first check if we + * have to change our interrupt state. + */ ld r5,SOFTE(r1) - TRACE_AND_RESTORE_IRQ(r5); + lbz r6,PACASOFTIRQEN(r13) + cmpwi cr1,r5,0 + cmpw cr0,r5,r6 + beq cr0,4f + + /* We do, handle disable first, which is easy */ + bne cr1,3f; + li r0,0 + stb r0,PACASOFTIRQEN(r13); + TRACE_DISABLE_INTS + b 4f - /* extract EE bit and use it to restore paca->hard_enabled */ - ld r3,_MSR(r1) - rldicl r4,r3,49,63 /* r0 = (r3 >> 15) & 1 */ - stb r4,PACAHARDIRQEN(r13) +3: /* + * We are about to soft-enable interrupts (we are hard disabled + * at this point). We check if there's anything that needs to + * be replayed first. + */ + lbz r0,PACAIRQHAPPENED(r13) + cmpwi cr0,r0,0 + bne- restore_check_irq_replay + + /* + * Get here when nothing happened while soft-disabled, just + * soft-enable and move-on. We will hard-enable as a side + * effect of rfi + */ +restore_no_replay: + TRACE_ENABLE_INTS + li r0,1 + stb r0,PACASOFTIRQEN(r13); + /* + * Final return path. BookE is handled in a different file + */ +4: #ifdef CONFIG_PPC_BOOK3E b .exception_return_book3e #else + /* + * Clear the reservation. If we know the CPU tracks the address of + * the reservation then we can potentially save some cycles and use + * a larx. On POWER6 and POWER7 this is significantly faster. + */ +BEGIN_FTR_SECTION + stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r4,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) + + /* + * Some code path such as load_up_fpu or altivec return directly + * here. They run entirely hard disabled and do not alter the + * interrupt state. They also don't use lwarx/stwcx. and thus + * are known not to leave dangling reservations. + */ + .globl fast_exception_return +fast_exception_return: + ld r3,_MSR(r1) ld r4,_CTR(r1) ld r0,_LINK(r1) mtctr r4 @@ -607,17 +662,6 @@ restore: andi. r0,r3,MSR_RI beq- unrecov_restore - /* - * Clear the reservation. If we know the CPU tracks the address of - * the reservation then we can potentially save some cycles and use - * a larx. On POWER6 and POWER7 this is significantly faster. - */ -BEGIN_FTR_SECTION - stdcx. r0,0,r1 /* to clear the reservation */ -FTR_SECTION_ELSE - ldarx r4,0,r1 -ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) - /* * Clear RI before restoring r13. If we are returning to * userspace and we take an exception after restoring r13, @@ -629,7 +673,8 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) /* * r13 is our per cpu area, only restore it if we are returning to - * userspace + * userspace the value stored in the stack frame may belong to + * another CPU. */ andi. r0,r3,MSR_PR beq 1f @@ -654,6 +699,55 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) #endif /* CONFIG_PPC_BOOK3E */ + /* + * Something did happen, check if a re-emit is needed + * (this also clears paca->irq_happened) + */ +restore_check_irq_replay: + /* XXX: We could implement a fast path here where we check + * for irq_happened being just 0x01, in which case we can + * clear it and return. That means that we would potentially + * miss a decrementer having wrapped all the way around. + * + * Still, this might be useful for things like hash_page + */ + bl .__check_irq_replay + cmpwi cr0,r3,0 + beq restore_no_replay + + /* + * We need to re-emit an interrupt. We do so by re-using our + * existing exception frame. We first change the trap value, + * but we need to ensure we preserve the low nibble of it + */ + ld r4,_TRAP(r1) + clrldi r4,r4,60 + or r4,r4,r3 + std r4,_TRAP(r1) + + /* + * Then find the right handler and call it. Interrupts are + * still soft-disabled and we keep them that way. + */ + cmpwi cr0,r3,0x500 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl .do_IRQ + b .ret_from_except +1: cmpwi cr0,r3,0x900 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl .timer_interrupt + b .ret_from_except +#ifdef CONFIG_PPC_BOOK3E +1: cmpwi cr0,r3,0x280 + bne 1f + addi r3,r1,STACK_FRAME_OVERHEAD; + bl .doorbell_exception + b .ret_from_except +#endif /* CONFIG_PPC_BOOK3E */ +1: b .ret_from_except /* What else to do here ? */ + do_work: #ifdef CONFIG_PREEMPT andi. r0,r3,MSR_PR /* Returning to user mode? */ @@ -666,18 +760,11 @@ do_work: crandc eq,cr1*4+eq,eq bne restore - /* Here we are preempting the current task. - * - * Ensure interrupts are soft-disabled. We also properly mark - * the PACA to reflect the fact that they are hard-disabled - * and trace the change + /* + * Here we are preempting the current task. We want to make + * sure we are soft-disabled first */ - li r0,0 - stb r0,PACASOFTIRQEN(r13) - stb r0,PACAHARDIRQEN(r13) - TRACE_DISABLE_INTS - - /* Call the scheduler with soft IRQs off */ + SOFT_DISABLE_INTS(r3,r4) 1: bl .preempt_schedule_irq /* Hard-disable interrupts again (and update PACA) */ @@ -687,8 +774,8 @@ do_work: ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */ mtmsrd r10,1 #endif /* CONFIG_PPC_BOOK3E */ - li r0,0 - stb r0,PACAHARDIRQEN(r13) + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) /* Re-test flags and eventually loop */ clrrdi r9,r1,THREAD_SHIFT @@ -710,14 +797,12 @@ user_work: andi. r0,r4,_TIF_NEED_RESCHED beq 1f - li r5,1 - TRACE_AND_RESTORE_IRQ(r5); + bl .restore_interrupts bl .schedule b .ret_from_except_lite 1: bl .save_nvgprs - li r5,1 - TRACE_AND_RESTORE_IRQ(r5); + bl .restore_interrupts addi r3,r1,STACK_FRAME_OVERHEAD bl .do_notify_resume b .ret_from_except diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index c4c34665c221..7215cc2495df 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -24,6 +24,7 @@ #include #include #include +#include /* XXX This will ultimately add space for a special exception save * structure used to save things like SRR0/SRR1, SPRGs, MAS, etc... @@ -77,59 +78,55 @@ #define SPRN_MC_SRR1 SPRN_MCSRR1 #define NORMAL_EXCEPTION_PROLOG(n, addition) \ - EXCEPTION_PROLOG(n, GEN, addition##_GEN) + EXCEPTION_PROLOG(n, GEN, addition##_GEN(n)) #define CRIT_EXCEPTION_PROLOG(n, addition) \ - EXCEPTION_PROLOG(n, CRIT, addition##_CRIT) + EXCEPTION_PROLOG(n, CRIT, addition##_CRIT(n)) #define DBG_EXCEPTION_PROLOG(n, addition) \ - EXCEPTION_PROLOG(n, DBG, addition##_DBG) + EXCEPTION_PROLOG(n, DBG, addition##_DBG(n)) #define MC_EXCEPTION_PROLOG(n, addition) \ - EXCEPTION_PROLOG(n, MC, addition##_MC) + EXCEPTION_PROLOG(n, MC, addition##_MC(n)) /* Variants of the "addition" argument for the prolog */ -#define PROLOG_ADDITION_NONE_GEN -#define PROLOG_ADDITION_NONE_CRIT -#define PROLOG_ADDITION_NONE_DBG -#define PROLOG_ADDITION_NONE_MC +#define PROLOG_ADDITION_NONE_GEN(n) +#define PROLOG_ADDITION_NONE_CRIT(n) +#define PROLOG_ADDITION_NONE_DBG(n) +#define PROLOG_ADDITION_NONE_MC(n) -#define PROLOG_ADDITION_MASKABLE_GEN \ +#define PROLOG_ADDITION_MASKABLE_GEN(n) \ lbz r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */ \ cmpwi cr0,r11,0; /* yes -> go out of line */ \ - beq masked_interrupt_book3e; + beq masked_interrupt_book3e_##n -#define PROLOG_ADDITION_2REGS_GEN \ +#define PROLOG_ADDITION_2REGS_GEN(n) \ std r14,PACA_EXGEN+EX_R14(r13); \ std r15,PACA_EXGEN+EX_R15(r13) -#define PROLOG_ADDITION_1REG_GEN \ +#define PROLOG_ADDITION_1REG_GEN(n) \ std r14,PACA_EXGEN+EX_R14(r13); -#define PROLOG_ADDITION_2REGS_CRIT \ +#define PROLOG_ADDITION_2REGS_CRIT(n) \ std r14,PACA_EXCRIT+EX_R14(r13); \ std r15,PACA_EXCRIT+EX_R15(r13) -#define PROLOG_ADDITION_2REGS_DBG \ +#define PROLOG_ADDITION_2REGS_DBG(n) \ std r14,PACA_EXDBG+EX_R14(r13); \ std r15,PACA_EXDBG+EX_R15(r13) -#define PROLOG_ADDITION_2REGS_MC \ +#define PROLOG_ADDITION_2REGS_MC(n) \ std r14,PACA_EXMC+EX_R14(r13); \ std r15,PACA_EXMC+EX_R15(r13) -#define PROLOG_ADDITION_DOORBELL_GEN \ - lbz r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */ \ - cmpwi cr0,r11,0; /* yes -> go out of line */ \ - beq masked_doorbell_book3e - /* Core exception code for all exceptions except TLB misses. * XXX: Needs to make SPRN_SPRG_GEN depend on exception type */ #define EXCEPTION_COMMON(n, excf, ints) \ +exc_##n##_common: \ std r0,GPR0(r1); /* save r0 in stackframe */ \ std r2,GPR2(r1); /* save r2 in stackframe */ \ SAVE_4GPRS(3, r1); /* save r3 - r6 in stackframe */ \ @@ -167,20 +164,21 @@ std r0,RESULT(r1); /* clear regs->result */ \ ints; -/* Variants for the "ints" argument */ +/* Variants for the "ints" argument. This one does nothing when we want + * to keep interrupts in their original state + */ #define INTS_KEEP -#define INTS_DISABLE_SOFT \ - stb r0,PACASOFTIRQEN(r13); /* mark interrupts soft-disabled */ \ - TRACE_DISABLE_INTS; -#define INTS_DISABLE_HARD \ - stb r0,PACAHARDIRQEN(r13); /* and hard disabled */ -#define INTS_DISABLE_ALL \ - INTS_DISABLE_SOFT \ - INTS_DISABLE_HARD - -/* This is called by exceptions that used INTS_KEEP (that is did not clear - * neither soft nor hard IRQ indicators in the PACA. This will restore MSR:EE - * to it's previous value + +/* This second version is meant for exceptions that don't immediately + * hard-enable. We set a bit in paca->irq_happened to ensure that + * a subsequent call to arch_local_irq_restore() will properly + * hard-enable and avoid the fast-path + */ +#define INTS_DISABLE SOFT_DISABLE_INTS(r3,r4) + +/* This is called by exceptions that used INTS_KEEP (that did not touch + * irq indicators in the PACA). This will restore MSR:EE to it's previous + * value * * XXX In the long run, we may want to open-code it in order to separate the * load from the wrtee, thus limiting the latency caused by the dependency @@ -238,7 +236,7 @@ exc_##n##_bad_stack: \ #define MASKABLE_EXCEPTION(trapnum, label, hdlr, ack) \ START_EXCEPTION(label); \ NORMAL_EXCEPTION_PROLOG(trapnum, PROLOG_ADDITION_MASKABLE) \ - EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE_ALL) \ + EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE) \ ack(r8); \ CHECK_NAPPING(); \ addi r3,r1,STACK_FRAME_OVERHEAD; \ @@ -289,7 +287,7 @@ interrupt_end_book3e: /* Critical Input Interrupt */ START_EXCEPTION(critical_input); CRIT_EXCEPTION_PROLOG(0x100, PROLOG_ADDITION_NONE) -// EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE_ALL) +// EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE) // bl special_reg_save_crit // CHECK_NAPPING(); // addi r3,r1,STACK_FRAME_OVERHEAD @@ -300,7 +298,7 @@ interrupt_end_book3e: /* Machine Check Interrupt */ START_EXCEPTION(machine_check); CRIT_EXCEPTION_PROLOG(0x200, PROLOG_ADDITION_NONE) -// EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE_ALL) +// EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE) // bl special_reg_save_mc // addi r3,r1,STACK_FRAME_OVERHEAD // CHECK_NAPPING(); @@ -313,7 +311,7 @@ interrupt_end_book3e: NORMAL_EXCEPTION_PROLOG(0x300, PROLOG_ADDITION_2REGS) mfspr r14,SPRN_DEAR mfspr r15,SPRN_ESR - EXCEPTION_COMMON(0x300, PACA_EXGEN, INTS_DISABLE_ALL) + EXCEPTION_COMMON(0x300, PACA_EXGEN, INTS_DISABLE) b storage_fault_common /* Instruction Storage Interrupt */ @@ -321,7 +319,7 @@ interrupt_end_book3e: NORMAL_EXCEPTION_PROLOG(0x400, PROLOG_ADDITION_2REGS) li r15,0 mr r14,r10 - EXCEPTION_COMMON(0x400, PACA_EXGEN, INTS_DISABLE_ALL) + EXCEPTION_COMMON(0x400, PACA_EXGEN, INTS_DISABLE) b storage_fault_common /* External Input Interrupt */ @@ -339,12 +337,11 @@ interrupt_end_book3e: START_EXCEPTION(program); NORMAL_EXCEPTION_PROLOG(0x700, PROLOG_ADDITION_1REG) mfspr r14,SPRN_ESR - EXCEPTION_COMMON(0x700, PACA_EXGEN, INTS_DISABLE_SOFT) + EXCEPTION_COMMON(0x700, PACA_EXGEN, INTS_DISABLE) std r14,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD ld r14,PACA_EXGEN+EX_R14(r13) bl .save_nvgprs - INTS_RESTORE_HARD bl .program_check_exception b .ret_from_except @@ -358,7 +355,7 @@ interrupt_end_book3e: beq- 1f bl .load_up_fpu b fast_exception_return -1: INTS_DISABLE_ALL +1: INTS_DISABLE bl .save_nvgprs addi r3,r1,STACK_FRAME_OVERHEAD bl .kernel_fp_unavailable_exception @@ -373,7 +370,7 @@ interrupt_end_book3e: /* Watchdog Timer Interrupt */ START_EXCEPTION(watchdog); CRIT_EXCEPTION_PROLOG(0x9f0, PROLOG_ADDITION_NONE) -// EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE_ALL) +// EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE) // bl special_reg_save_crit // CHECK_NAPPING(); // addi r3,r1,STACK_FRAME_OVERHEAD @@ -392,7 +389,7 @@ interrupt_end_book3e: /* Auxiliary Processor Unavailable Interrupt */ START_EXCEPTION(ap_unavailable); NORMAL_EXCEPTION_PROLOG(0xf20, PROLOG_ADDITION_NONE) - EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_DISABLE_ALL) + EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_DISABLE) bl .save_nvgprs addi r3,r1,STACK_FRAME_OVERHEAD bl .unknown_exception @@ -450,7 +447,7 @@ interrupt_end_book3e: mfspr r15,SPRN_SPRG_CRIT_SCRATCH mtspr SPRN_SPRG_GEN_SCRATCH,r15 mfspr r14,SPRN_DBSR - EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE_ALL) + EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE) std r14,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD mr r4,r14 @@ -465,7 +462,7 @@ kernel_dbg_exc: /* Debug exception as a debug interrupt*/ START_EXCEPTION(debug_debug); - DBG_EXCEPTION_PROLOG(0xd00, PROLOG_ADDITION_2REGS) + DBG_EXCEPTION_PROLOG(0xd08, PROLOG_ADDITION_2REGS) /* * If there is a single step or branch-taken exception in an @@ -515,7 +512,7 @@ kernel_dbg_exc: mfspr r15,SPRN_SPRG_DBG_SCRATCH mtspr SPRN_SPRG_GEN_SCRATCH,r15 mfspr r14,SPRN_DBSR - EXCEPTION_COMMON(0xd00, PACA_EXDBG, INTS_DISABLE_ALL) + EXCEPTION_COMMON(0xd08, PACA_EXDBG, INTS_DISABLE) std r14,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD mr r4,r14 @@ -525,21 +522,20 @@ kernel_dbg_exc: bl .DebugException b .ret_from_except - MASKABLE_EXCEPTION(0x260, perfmon, .performance_monitor_exception, ACK_NONE) - -/* Doorbell interrupt */ - START_EXCEPTION(doorbell) - NORMAL_EXCEPTION_PROLOG(0x2070, PROLOG_ADDITION_DOORBELL) - EXCEPTION_COMMON(0x2070, PACA_EXGEN, INTS_DISABLE_ALL) - CHECK_NAPPING() + START_EXCEPTION(perfmon); + NORMAL_EXCEPTION_PROLOG(0x260, PROLOG_ADDITION_NONE) + EXCEPTION_COMMON(0x260, PACA_EXGEN, INTS_DISABLE) addi r3,r1,STACK_FRAME_OVERHEAD - bl .doorbell_exception + bl .performance_monitor_exception b .ret_from_except_lite +/* Doorbell interrupt */ + MASKABLE_EXCEPTION(0x280, doorbell, .doorbell_exception, ACK_NONE) + /* Doorbell critical Interrupt */ START_EXCEPTION(doorbell_crit); - CRIT_EXCEPTION_PROLOG(0x2080, PROLOG_ADDITION_NONE) -// EXCEPTION_COMMON(0x2080, PACA_EXCRIT, INTS_DISABLE_ALL) + CRIT_EXCEPTION_PROLOG(0x2a0, PROLOG_ADDITION_NONE) +// EXCEPTION_COMMON(0x2a0, PACA_EXCRIT, INTS_DISABLE) // bl special_reg_save_crit // CHECK_NAPPING(); // addi r3,r1,STACK_FRAME_OVERHEAD @@ -547,36 +543,114 @@ kernel_dbg_exc: // b ret_from_crit_except b . +/* Guest Doorbell */ MASKABLE_EXCEPTION(0x2c0, guest_doorbell, .unknown_exception, ACK_NONE) - MASKABLE_EXCEPTION(0x2e0, guest_doorbell_crit, .unknown_exception, ACK_NONE) - MASKABLE_EXCEPTION(0x310, hypercall, .unknown_exception, ACK_NONE) - MASKABLE_EXCEPTION(0x320, ehpriv, .unknown_exception, ACK_NONE) +/* Guest Doorbell critical Interrupt */ + START_EXCEPTION(guest_doorbell_crit); + CRIT_EXCEPTION_PROLOG(0x2e0, PROLOG_ADDITION_NONE) +// EXCEPTION_COMMON(0x2e0, PACA_EXCRIT, INTS_DISABLE) +// bl special_reg_save_crit +// CHECK_NAPPING(); +// addi r3,r1,STACK_FRAME_OVERHEAD +// bl .guest_doorbell_critical_exception +// b ret_from_crit_except + b . + +/* Hypervisor call */ + START_EXCEPTION(hypercall); + NORMAL_EXCEPTION_PROLOG(0x310, PROLOG_ADDITION_NONE) + EXCEPTION_COMMON(0x310, PACA_EXGEN, INTS_KEEP) + addi r3,r1,STACK_FRAME_OVERHEAD + bl .save_nvgprs + INTS_RESTORE_HARD + bl .unknown_exception + b .ret_from_except + +/* Embedded Hypervisor priviledged */ + START_EXCEPTION(ehpriv); + NORMAL_EXCEPTION_PROLOG(0x320, PROLOG_ADDITION_NONE) + EXCEPTION_COMMON(0x320, PACA_EXGEN, INTS_KEEP) + addi r3,r1,STACK_FRAME_OVERHEAD + bl .save_nvgprs + INTS_RESTORE_HARD + bl .unknown_exception + b .ret_from_except /* - * An interrupt came in while soft-disabled; clear EE in SRR1, - * clear paca->hard_enabled and return. + * An interrupt came in while soft-disabled; We mark paca->irq_happened + * accordingly and if the interrupt is level sensitive, we hard disable */ -masked_doorbell_book3e: - mtcr r10 - /* Resend the doorbell to fire again when ints enabled */ - mfspr r10,SPRN_PIR - PPC_MSGSND(r10) - b masked_interrupt_book3e_common -masked_interrupt_book3e: +masked_interrupt_book3e_0x500: + /* XXX When adding support for EPR, use PACA_IRQ_EE_EDGE */ + li r11,PACA_IRQ_EE + b masked_interrupt_book3e_full_mask + +masked_interrupt_book3e_0x900: + ACK_DEC(r11); + li r11,PACA_IRQ_DEC + b masked_interrupt_book3e_no_mask +masked_interrupt_book3e_0x980: + ACK_FIT(r11); + li r11,PACA_IRQ_DEC + b masked_interrupt_book3e_no_mask +masked_interrupt_book3e_0x280: +masked_interrupt_book3e_0x2c0: + li r11,PACA_IRQ_DBELL + b masked_interrupt_book3e_no_mask + +masked_interrupt_book3e_no_mask: mtcr r10 -masked_interrupt_book3e_common: - stb r11,PACAHARDIRQEN(r13) + lbz r10,PACAIRQHAPPENED(r13) + or r10,r10,r11 + stb r10,PACAIRQHAPPENED(r13) + b 1f +masked_interrupt_book3e_full_mask: + mtcr r10 + lbz r10,PACAIRQHAPPENED(r13) + or r10,r10,r11 + stb r10,PACAIRQHAPPENED(r13) mfspr r10,SPRN_SRR1 rldicl r11,r10,48,1 /* clear MSR_EE */ rotldi r10,r11,16 mtspr SPRN_SRR1,r10 - ld r10,PACA_EXGEN+EX_R10(r13); /* restore registers */ +1: ld r10,PACA_EXGEN+EX_R10(r13); ld r11,PACA_EXGEN+EX_R11(r13); mfspr r13,SPRN_SPRG_GEN_SCRATCH; rfi b . +/* + * Called from arch_local_irq_enable when an interrupt needs + * to be resent. r3 contains either 0x500,0x900,0x260 or 0x280 + * to indicate the kind of interrupt. MSR:EE is already off. + * We generate a stackframe like if a real interrupt had happened. + * + * Note: While MSR:EE is off, we need to make sure that _MSR + * in the generated frame has EE set to 1 or the exception + * handler will not properly re-enable them. + */ +_GLOBAL(__replay_interrupt) + /* We are going to jump to the exception common code which + * will retrieve various register values from the PACA which + * we don't give a damn about. + */ + mflr r10 + mfmsr r11 + mfcr r4 + mtspr SPRN_SPRG_GEN_SCRATCH,r13; + std r1,PACA_EXGEN+EX_R1(r13); + stw r4,PACA_EXGEN+EX_CR(r13); + ori r11,r11,MSR_EE + subi r1,r1,INT_FRAME_SIZE; + cmpwi cr0,r3,0x500 + beq exc_0x500_common + cmpwi cr0,r3,0x900 + beq exc_0x900_common + cmpwi cr0,r3,0x280 + beq exc_0x280_common + blr + /* * This is called from 0x300 and 0x400 handlers after the prologs with @@ -679,6 +753,8 @@ BAD_STACK_TRAMPOLINE(0x000) BAD_STACK_TRAMPOLINE(0x100) BAD_STACK_TRAMPOLINE(0x200) BAD_STACK_TRAMPOLINE(0x260) +BAD_STACK_TRAMPOLINE(0x280) +BAD_STACK_TRAMPOLINE(0x2a0) BAD_STACK_TRAMPOLINE(0x2c0) BAD_STACK_TRAMPOLINE(0x2e0) BAD_STACK_TRAMPOLINE(0x300) @@ -696,11 +772,10 @@ BAD_STACK_TRAMPOLINE(0xa00) BAD_STACK_TRAMPOLINE(0xb00) BAD_STACK_TRAMPOLINE(0xc00) BAD_STACK_TRAMPOLINE(0xd00) +BAD_STACK_TRAMPOLINE(0xd08) BAD_STACK_TRAMPOLINE(0xe00) BAD_STACK_TRAMPOLINE(0xf00) BAD_STACK_TRAMPOLINE(0xf20) -BAD_STACK_TRAMPOLINE(0x2070) -BAD_STACK_TRAMPOLINE(0x2080) .globl bad_stack_book3e bad_stack_book3e: diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 02448ea58ad3..2d0868a4e2f0 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -12,6 +12,7 @@ * */ +#include #include #include @@ -356,34 +357,60 @@ do_stab_bolted_pSeries: KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0xf40) /* - * An interrupt came in while soft-disabled; clear EE in SRR1, - * clear paca->hard_enabled and return. + * An interrupt came in while soft-disabled. We set paca->irq_happened, + * then, if it was a decrementer interrupt, we bump the dec to max and + * and return, else we hard disable and return. This is called with + * r10 containing the value to OR to the paca field. */ -masked_interrupt: - stb r10,PACAHARDIRQEN(r13) - mtcrf 0x80,r9 - ld r9,PACA_EXGEN+EX_R9(r13) - mfspr r10,SPRN_SRR1 - rldicl r10,r10,48,1 /* clear MSR_EE */ - rotldi r10,r10,16 - mtspr SPRN_SRR1,r10 - ld r10,PACA_EXGEN+EX_R10(r13) - GET_SCRATCH0(r13) - rfid +#define MASKED_INTERRUPT(_H) \ +masked_##_H##interrupt: \ + std r11,PACA_EXGEN+EX_R11(r13); \ + lbz r11,PACAIRQHAPPENED(r13); \ + or r11,r11,r10; \ + stb r11,PACAIRQHAPPENED(r13); \ + andi. r10,r10,PACA_IRQ_DEC; \ + beq 1f; \ + lis r10,0x7fff; \ + ori r10,r10,0xffff; \ + mtspr SPRN_DEC,r10; \ + b 2f; \ +1: mfspr r10,SPRN_##_H##SRR1; \ + rldicl r10,r10,48,1; /* clear MSR_EE */ \ + rotldi r10,r10,16; \ + mtspr SPRN_##_H##SRR1,r10; \ +2: mtcrf 0x80,r9; \ + ld r9,PACA_EXGEN+EX_R9(r13); \ + ld r10,PACA_EXGEN+EX_R10(r13); \ + ld r11,PACA_EXGEN+EX_R11(r13); \ + GET_SCRATCH0(r13); \ + ##_H##rfid; \ b . + + MASKED_INTERRUPT() + MASKED_INTERRUPT(H) -masked_Hinterrupt: - stb r10,PACAHARDIRQEN(r13) - mtcrf 0x80,r9 - ld r9,PACA_EXGEN+EX_R9(r13) - mfspr r10,SPRN_HSRR1 - rldicl r10,r10,48,1 /* clear MSR_EE */ - rotldi r10,r10,16 - mtspr SPRN_HSRR1,r10 - ld r10,PACA_EXGEN+EX_R10(r13) - GET_SCRATCH0(r13) - hrfid - b . +/* + * Called from arch_local_irq_enable when an interrupt needs + * to be resent. r3 contains 0x500 or 0x900 to indicate which + * kind of interrupt. MSR:EE is already off. We generate a + * stackframe like if a real interrupt had happened. + * + * Note: While MSR:EE is off, we need to make sure that _MSR + * in the generated frame has EE set to 1 or the exception + * handler will not properly re-enable them. + */ +_GLOBAL(__replay_interrupt) + /* We are going to jump to the exception common code which + * will retrieve various register values from the PACA which + * we don't give a damn about, so we don't bother storing them. + */ + mfmsr r12 + mflr r11 + mfcr r9 + ori r12,r12,MSR_EE + andi. r3,r3,0x0800 + bne decrementer_common + b hardware_interrupt_common #ifdef CONFIG_PPC_PSERIES /* @@ -793,7 +820,8 @@ vsx_unavailable_common: EXCEPTION_PROLOG_COMMON(0xf40, PACA_EXGEN) #ifdef CONFIG_VSX BEGIN_FTR_SECTION - bne .load_up_vsx + beq 1f + b .load_up_vsx 1: END_FTR_SECTION_IFSET(CPU_FTR_VSX) #endif @@ -807,65 +835,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) .globl __end_handlers __end_handlers: -/* - * Return from an exception with minimal checks. - * The caller is assumed to have done EXCEPTION_PROLOG_COMMON. - * If interrupts have been enabled, or anything has been - * done that might have changed the scheduling status of - * any task or sent any task a signal, you should use - * ret_from_except or ret_from_except_lite instead of this. - */ -fast_exc_return_irq: /* restores irq state too */ - ld r3,SOFTE(r1) - TRACE_AND_RESTORE_IRQ(r3); - ld r12,_MSR(r1) - rldicl r4,r12,49,63 /* get MSR_EE to LSB */ - stb r4,PACAHARDIRQEN(r13) /* restore paca->hard_enabled */ - b 1f - - .globl fast_exception_return -fast_exception_return: - ld r12,_MSR(r1) -1: ld r11,_NIP(r1) - andi. r3,r12,MSR_RI /* check if RI is set */ - beq- unrecov_fer - -#ifdef CONFIG_VIRT_CPU_ACCOUNTING - andi. r3,r12,MSR_PR - beq 2f - ACCOUNT_CPU_USER_EXIT(r3, r4) -2: -#endif - - ld r3,_CCR(r1) - ld r4,_LINK(r1) - ld r5,_CTR(r1) - ld r6,_XER(r1) - mtcr r3 - mtlr r4 - mtctr r5 - mtxer r6 - REST_GPR(0, r1) - REST_8GPRS(2, r1) - - ld r10,PACAKMSR(r13) - clrrdi r10,r10,2 /* clear RI */ - mtmsrd r10,1 - - mtspr SPRN_SRR1,r12 - mtspr SPRN_SRR0,r11 - REST_4GPRS(10, r1) - ld r1,GPR1(r1) - rfid - b . /* prevent speculative execution */ - -unrecov_fer: - bl .save_nvgprs -1: addi r3,r1,STACK_FRAME_OVERHEAD - bl .unrecoverable_exception - b 1b - - /* * Hash table stuff */ @@ -905,19 +874,16 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_SLB) * r4 contains the required access permissions * r5 contains the trap number * - * at return r3 = 0 for success + * at return r3 = 0 for success, 1 for page fault, negative for error */ bl .hash_page /* build HPTE if possible */ cmpdi r3,0 /* see if hash_page succeeded */ - /* - * Here we have interrupts hard-disabled, so it is sufficient - * to restore paca->{soft,hard}_enable and get out. - */ + /* Success */ beq fast_exc_return_irq /* Return from exception on success */ - /* For a hash failure, we don't bother re-enabling interrupts */ - ble- 13f + /* Error */ + blt- 13f /* Here we have a page fault that hash_page can't handle. */ handle_page_fault: diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 40759fbfb171..58bddee8e1e8 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -38,6 +38,7 @@ #include #include #include +#include /* The physical memory is laid out such that the secondary processor * spin code sits at 0x0000...0x00ff. On server, the vectors follow @@ -550,7 +551,8 @@ _GLOBAL(pmac_secondary_start) */ li r0,0 stb r0,PACASOFTIRQEN(r13) - stb r0,PACAHARDIRQEN(r13) + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) /* Create a temp kernel stack for use before relocation is on. */ ld r1,PACAEMERGSP(r13) @@ -601,9 +603,12 @@ __secondary_start: li r7,0 mtlr r7 - /* Mark interrupts both hard and soft disabled */ - stb r7,PACAHARDIRQEN(r13) + /* Mark interrupts soft and hard disabled (they might be enabled + * in the PACA when doing hotplug) + */ stb r7,PACASOFTIRQEN(r13) + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) /* enable MMU and jump to start_secondary */ LOAD_REG_ADDR(r3, .start_secondary_prolog) @@ -750,13 +755,18 @@ _INIT_GLOBAL(start_here_common) /* Load the TOC (virtual address) */ ld r2,PACATOC(r13) + /* Do more system initializations in virtual mode */ bl .setup_system - /* Load up the kernel context */ -5: li r5,0 - stb r5,PACASOFTIRQEN(r13) /* Soft Disabled */ - stb r5,PACAHARDIRQEN(r13) /* Hard Disabled on others */ + /* Mark interrupts soft and hard disabled (they might be enabled + * in the PACA when doing hotplug) + */ + li r0,0 + stb r0,PACASOFTIRQEN(r13) + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) + /* Generic kernel entry */ bl .start_kernel /* Not reached */ diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c index 0a48bf5db6c8..8f7a2b62863d 100644 --- a/arch/powerpc/kernel/idle.c +++ b/arch/powerpc/kernel/idle.c @@ -84,7 +84,11 @@ void cpu_idle(void) start_critical_timings(); - local_irq_enable(); + /* Some power_save functions return with + * interrupts enabled, some don't. + */ + if (irqs_disabled()) + local_irq_enable(); set_thread_flag(TIF_POLLING_NRFLAG); } else { diff --git a/arch/powerpc/kernel/idle_book3e.S b/arch/powerpc/kernel/idle_book3e.S index 16c002d6bdf1..ff007b59448d 100644 --- a/arch/powerpc/kernel/idle_book3e.S +++ b/arch/powerpc/kernel/idle_book3e.S @@ -29,43 +29,30 @@ _GLOBAL(book3e_idle) wrteei 0 /* Now check if an interrupt came in while we were soft disabled - * since we may otherwise lose it (doorbells etc...). We know - * that since PACAHARDIRQEN will have been cleared in that case. + * since we may otherwise lose it (doorbells etc...). */ - lbz r3,PACAHARDIRQEN(r13) + lbz r3,PACAIRQHAPPENED(r13) cmpwi cr0,r3,0 - beqlr + bnelr - /* Now we are going to mark ourselves as soft and hard enables in + /* Now we are going to mark ourselves as soft and hard enabled in * order to be able to take interrupts while asleep. We inform lockdep * of that. We don't actually turn interrupts on just yet tho. */ #ifdef CONFIG_TRACE_IRQFLAGS stdu r1,-128(r1) bl .trace_hardirqs_on + addi r1,r1,128 #endif li r0,1 stb r0,PACASOFTIRQEN(r13) - stb r0,PACAHARDIRQEN(r13) /* Interrupts will make use return to LR, so get something we want * in there */ bl 1f - /* Hard disable interrupts again */ - wrteei 0 - - /* Mark them off again in the PACA as well */ - li r0,0 - stb r0,PACASOFTIRQEN(r13) - stb r0,PACAHARDIRQEN(r13) - - /* Tell lockdep about it */ -#ifdef CONFIG_TRACE_IRQFLAGS - bl .trace_hardirqs_off - addi r1,r1,128 -#endif + /* And return (interrupts are on) */ ld r0,16(r1) mtlr r0 blr diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S index ba3195478600..d8cdba4c28b2 100644 --- a/arch/powerpc/kernel/idle_power4.S +++ b/arch/powerpc/kernel/idle_power4.S @@ -14,6 +14,7 @@ #include #include #include +#include #undef DEBUG @@ -29,14 +30,31 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP) cmpwi 0,r4,0 beqlr - /* Go to NAP now */ + /* Hard disable interrupts */ mfmsr r7 rldicl r0,r7,48,1 rotldi r0,r0,16 - mtmsrd r0,1 /* hard-disable interrupts */ + mtmsrd r0,1 + + /* Check if something happened while soft-disabled */ + lbz r0,PACAIRQHAPPENED(r13) + cmpwi cr0,r0,0 + bnelr + + /* Soft-enable interrupts */ +#ifdef CONFIG_TRACE_IRQFLAGS + mflr r0 + std r0,16(r1) + stdu r1,-128(r1) + bl .trace_hardirqs_on + addi r1,r1,128 + ld r0,16(r1) + mtlr r0 +#endif /* CONFIG_TRACE_IRQFLAGS */ + + TRACE_ENABLE_INTS li r0,1 stb r0,PACASOFTIRQEN(r13) /* we'll hard-enable shortly */ - stb r0,PACAHARDIRQEN(r13) BEGIN_FTR_SECTION DSSALL sync diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S index fcdff198da4b..0cdc9a392839 100644 --- a/arch/powerpc/kernel/idle_power7.S +++ b/arch/powerpc/kernel/idle_power7.S @@ -1,5 +1,5 @@ /* - * This file contains the power_save function for 970-family CPUs. + * This file contains the power_save function for Power7 CPUs. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -15,6 +15,7 @@ #include #include #include +#include #undef DEBUG @@ -51,9 +52,25 @@ _GLOBAL(power7_idle) rldicl r9,r9,48,1 rotldi r9,r9,16 mtmsrd r9,1 /* hard-disable interrupts */ + + /* Check if something happened while soft-disabled */ + lbz r0,PACAIRQHAPPENED(r13) + cmpwi cr0,r0,0 + beq 1f + addi r1,r1,INT_FRAME_SIZE + ld r0,16(r1) + mtlr r0 + blr + +1: /* We mark irqs hard disabled as this is the state we'll + * be in when returning and we need to tell arch_local_irq_restore() + * about it + */ + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) + + /* We haven't lost state ... yet */ li r0,0 - stb r0,PACASOFTIRQEN(r13) /* we'll hard-enable shortly */ - stb r0,PACAHARDIRQEN(r13) stb r0,PACA_NAPSTATELOST(r13) /* Continue saving state */ diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 9b6e80668cfb..eb804e15b29b 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -95,14 +95,14 @@ extern int tau_interrupts(int); int distribute_irqs = 1; -static inline notrace unsigned long get_hard_enabled(void) +static inline notrace unsigned long get_irq_happened(void) { - unsigned long enabled; + unsigned long happened; __asm__ __volatile__("lbz %0,%1(13)" - : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled))); + : "=r" (happened) : "i" (offsetof(struct paca_struct, irq_happened))); - return enabled; + return happened; } static inline notrace void set_soft_enabled(unsigned long enable) @@ -111,88 +111,167 @@ static inline notrace void set_soft_enabled(unsigned long enable) : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled))); } -static inline notrace void decrementer_check_overflow(void) +static inline notrace int decrementer_check_overflow(void) { - u64 now = get_tb_or_rtc(); - u64 *next_tb; - - preempt_disable(); - next_tb = &__get_cpu_var(decrementers_next_tb); - + u64 now = get_tb_or_rtc(); + u64 *next_tb = &__get_cpu_var(decrementers_next_tb); + if (now >= *next_tb) set_dec(1); - preempt_enable(); + return now >= *next_tb; } -notrace void arch_local_irq_restore(unsigned long en) +/* This is called whenever we are re-enabling interrupts + * and returns either 0 (nothing to do) or 500/900 if there's + * either an EE or a DEC to generate. + * + * This is called in two contexts: From arch_local_irq_restore() + * before soft-enabling interrupts, and from the exception exit + * path when returning from an interrupt from a soft-disabled to + * a soft enabled context. In both case we have interrupts hard + * disabled. + * + * We take care of only clearing the bits we handled in the + * PACA irq_happened field since we can only re-emit one at a + * time and we don't want to "lose" one. + */ +notrace unsigned int __check_irq_replay(void) { /* - * get_paca()->soft_enabled = en; - * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1? - * That was allowed before, and in such a case we do need to take care - * that gcc will set soft_enabled directly via r13, not choose to use - * an intermediate register, lest we're preempted to a different cpu. + * We use local_paca rather than get_paca() to avoid all + * the debug_smp_processor_id() business in this low level + * function */ - set_soft_enabled(en); - if (!en) - return; + unsigned char happened = local_paca->irq_happened; -#ifdef CONFIG_PPC_STD_MMU_64 - if (firmware_has_feature(FW_FEATURE_ISERIES)) { - /* - * Do we need to disable preemption here? Not really: in the - * unlikely event that we're preempted to a different cpu in - * between getting r13, loading its lppaca_ptr, and loading - * its any_int, we might call iseries_handle_interrupts without - * an interrupt pending on the new cpu, but that's no disaster, - * is it? And the business of preempting us off the old cpu - * would itself involve a local_irq_restore which handles the - * interrupt to that cpu. - * - * But use "local_paca->lppaca_ptr" instead of "get_lppaca()" - * to avoid any preemption checking added into get_paca(). - */ - if (local_paca->lppaca_ptr->int_dword.any_int) - iseries_handle_interrupts(); + /* Clear bit 0 which we wouldn't clear otherwise */ + local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS; + + /* + * Force the delivery of pending soft-disabled interrupts on PS3. + * Any HV call will have this side effect. + */ + if (firmware_has_feature(FW_FEATURE_PS3_LV1)) { + u64 tmp, tmp2; + lv1_get_version_info(&tmp, &tmp2); } -#endif /* CONFIG_PPC_STD_MMU_64 */ /* - * if (get_paca()->hard_enabled) return; - * But again we need to take care that gcc gets hard_enabled directly - * via r13, not choose to use an intermediate register, lest we're - * preempted to a different cpu in between the two instructions. + * We may have missed a decrementer interrupt. We check the + * decrementer itself rather than the paca irq_happened field + * in case we also had a rollover while hard disabled + */ + local_paca->irq_happened &= ~PACA_IRQ_DEC; + if (decrementer_check_overflow()) + return 0x900; + + /* Finally check if an external interrupt happened */ + local_paca->irq_happened &= ~PACA_IRQ_EE; + if (happened & PACA_IRQ_EE) + return 0x500; + +#ifdef CONFIG_PPC_BOOK3E + /* Finally check if an EPR external interrupt happened + * this bit is typically set if we need to handle another + * "edge" interrupt from within the MPIC "EPR" handler + */ + local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE; + if (happened & PACA_IRQ_EE_EDGE) + return 0x500; + + local_paca->irq_happened &= ~PACA_IRQ_DBELL; + if (happened & PACA_IRQ_DBELL) + return 0x280; +#endif /* CONFIG_PPC_BOOK3E */ + + /* There should be nothing left ! */ + BUG_ON(local_paca->irq_happened != 0); + + return 0; +} + +notrace void arch_local_irq_restore(unsigned long en) +{ + unsigned char irq_happened; + unsigned int replay; + + /* Write the new soft-enabled value */ + set_soft_enabled(en); + if (!en) + return; + /* + * From this point onward, we can take interrupts, preempt, + * etc... unless we got hard-disabled. We check if an event + * happened. If none happened, we know we can just return. + * + * We may have preempted before the check below, in which case + * we are checking the "new" CPU instead of the old one. This + * is only a problem if an event happened on the "old" CPU. + * + * External interrupt events on non-iseries will have caused + * interrupts to be hard-disabled, so there is no problem, we + * cannot have preempted. + * + * That leaves us with EEs on iSeries or decrementer interrupts, + * which I decided to safely ignore. The preemption would have + * itself been the result of an interrupt, upon which return we + * will have checked for pending events on the old CPU. */ - if (get_hard_enabled()) + irq_happened = get_irq_happened(); + if (!irq_happened) return; /* - * Need to hard-enable interrupts here. Since currently disabled, - * no need to take further asm precautions against preemption; but - * use local_paca instead of get_paca() to avoid preemption checking. + * We need to hard disable to get a trusted value from + * __check_irq_replay(). We also need to soft-disable + * again to avoid warnings in there due to the use of + * per-cpu variables. + * + * We know that if the value in irq_happened is exactly 0x01 + * then we are already hard disabled (there are other less + * common cases that we'll ignore for now), so we skip the + * (expensive) mtmsrd. */ - local_paca->hard_enabled = en; + if (unlikely(irq_happened != PACA_IRQ_HARD_DIS)) + __hard_irq_disable(); + set_soft_enabled(0); /* - * Trigger the decrementer if we have a pending event. Some processors - * only trigger on edge transitions of the sign bit. We might also - * have disabled interrupts long enough that the decrementer wrapped - * to positive. + * Check if anything needs to be re-emitted. We haven't + * soft-enabled yet to avoid warnings in decrementer_check_overflow + * accessing per-cpu variables */ - decrementer_check_overflow(); + replay = __check_irq_replay(); + + /* We can soft-enable now */ + set_soft_enabled(1); /* - * Force the delivery of pending soft-disabled interrupts on PS3. - * Any HV call will have this side effect. + * And replay if we have to. This will return with interrupts + * hard-enabled. */ - if (firmware_has_feature(FW_FEATURE_PS3_LV1)) { - u64 tmp, tmp2; - lv1_get_version_info(&tmp, &tmp2); + if (replay) { + __replay_interrupt(replay); + return; } + /* Finally, let's ensure we are hard enabled */ __hard_irq_enable(); } EXPORT_SYMBOL(arch_local_irq_restore); + +/* + * This is specifically called by assembly code to re-enable interrupts + * if they are currently disabled. This is typically called before + * schedule() or do_signal() when returning to userspace. We do it + * in C to avoid the burden of dealing with lockdep etc... + */ +void restore_interrupts(void) +{ + if (irqs_disabled()) + local_irq_enable(); +} + #endif /* CONFIG_PPC64 */ int arch_show_interrupts(struct seq_file *p, int prec) @@ -360,8 +439,17 @@ void do_IRQ(struct pt_regs *regs) check_stack_overflow(); + /* + * Query the platform PIC for the interrupt & ack it. + * + * This will typically lower the interrupt line to the CPU + */ irq = ppc_md.get_irq(); + /* We can hard enable interrupts now */ + may_hard_irq_enable(); + + /* And finally process it */ if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) handle_one_irq(irq); else if (irq != NO_IRQ_IGNORE) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index bf80a1d5f8fe..e40707032ac3 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -647,6 +647,9 @@ void show_regs(struct pt_regs * regs) printk("MSR: "REG" ", regs->msr); printbits(regs->msr, msr_bits); printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); +#ifdef CONFIG_PPC64 + printk("SOFTE: %ld\n", regs->softe); +#endif trap = TRAP(regs); if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR)) printk("CFAR: "REG"\n", regs->orig_gpr3); diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 567dd7c3ac2a..f81c81b92f0e 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -259,7 +259,6 @@ void accumulate_stolen_time(void) u64 sst, ust; u8 save_soft_enabled = local_paca->soft_enabled; - u8 save_hard_enabled = local_paca->hard_enabled; /* We are called early in the exception entry, before * soft/hard_enabled are sync'ed to the expected state @@ -268,7 +267,6 @@ void accumulate_stolen_time(void) * complain */ local_paca->soft_enabled = 0; - local_paca->hard_enabled = 0; sst = scan_dispatch_log(local_paca->starttime_user); ust = scan_dispatch_log(local_paca->starttime); @@ -277,7 +275,6 @@ void accumulate_stolen_time(void) local_paca->stolen_time += ust + sst; local_paca->soft_enabled = save_soft_enabled; - local_paca->hard_enabled = save_hard_enabled; } static inline u64 calculate_stolen_time(u64 stop_tb) @@ -580,6 +577,11 @@ void timer_interrupt(struct pt_regs * regs) if (!cpu_online(smp_processor_id())) return; + /* Conditionally hard-enable interrupts now that the DEC has been + * bumped to its maximum value + */ + may_hard_irq_enable(); + trace_timer_interrupt_entry(regs); __get_cpu_var(irq_stat).timer_irqs++; diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index 085fd3f45ad2..a12e95af6933 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -96,6 +96,20 @@ out: return index; } +static void check_and_cede_processor(void) +{ + /* + * Interrupts are soft-disabled at this point, + * but not hard disabled. So an interrupt might have + * occurred before entering NAP, and would be potentially + * lost (edge events, decrementer events, etc...) unless + * we first hard disable then check. + */ + hard_irq_disable(); + if (get_paca()->irq_happened == 0) + cede_processor(); +} + static int dedicated_cede_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) @@ -108,7 +122,7 @@ static int dedicated_cede_loop(struct cpuidle_device *dev, ppc64_runlatch_off(); HMT_medium(); - cede_processor(); + check_and_cede_processor(); get_lppaca()->donate_dedicated_cpu = 0; dev->last_residency = @@ -132,7 +146,7 @@ static int shared_cede_loop(struct cpuidle_device *dev, * processor. When returning here, external interrupts * are enabled. */ - cede_processor(); + check_and_cede_processor(); dev->last_residency = (int)idle_loop_epilog(in_purr, kt_before); diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 63846ebd3276..974a47b3c9b8 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -1437,8 +1437,8 @@ static void excprint(struct pt_regs *fp) printf(" current = 0x%lx\n", current); #ifdef CONFIG_PPC64 - printf(" paca = 0x%lx\t softe: %d\t harde: %d\n", - local_paca, local_paca->soft_enabled, local_paca->hard_enabled); + printf(" paca = 0x%lx\t softe: %d\t irq_happened: 0x%02x\n", + local_paca, local_paca->soft_enabled, local_paca->irq_happened); #endif if (current) { printf(" pid = %ld, comm = %s\n", -- 2.20.1