From bf9282dc26e7fe2a0736edc568762f0f05d12416 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 12 Aug 2020 12:22:17 +0200 Subject: cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic This allows moving the leave_mm() call into generic code before rcu_idle_enter(). Gets rid of more trace_*_rcuidle() users. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.369441600@infradead.org --- arch/x86/include/asm/mmu.h | 1 + arch/x86/mm/tlb.c | 13 ++----------- 2 files changed, 3 insertions(+), 11 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 0a301ad0b02f..9257667d13c5 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -59,5 +59,6 @@ typedef struct { } void leave_mm(int cpu); +#define leave_mm leave_mm #endif /* _ASM_X86_MMU_H */ diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 1a3569b43aa5..0951b47e64c1 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -555,21 +555,12 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen); load_new_mm_cr3(next->pgd, new_asid, true); - /* - * NB: This gets called via leave_mm() in the idle path - * where RCU functions differently. Tracing normally - * uses RCU, so we need to use the _rcuidle variant. - * - * (There is no good reason for this. The idle code should - * be rearranged to call this before rcu_idle_enter().) - */ - trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); } else { /* The new ASID is already up to date. */ load_new_mm_cr3(next->pgd, new_asid, false); - /* See above wrt _rcuidle. */ - trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, 0); } /* Make sure we write CR3 before loaded_mm. */ -- cgit v1.2.3 From 9864f5b5943ab0f1f835f21dc3f9f068d06f5b52 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 12 Aug 2020 12:27:10 +0200 Subject: cpuidle: Move trace_cpu_idle() into generic code Remove trace_cpu_idle() from the arch_cpu_idle() implementations and put it in the generic code, right before disabling RCU. Gets rid of more trace_*_rcuidle() users. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.428433395@infradead.org --- arch/arm/mach-omap2/pm34xx.c | 4 ---- arch/arm64/kernel/process.c | 2 -- arch/s390/kernel/idle.c | 3 +-- arch/x86/kernel/process.c | 4 ---- kernel/sched/idle.c | 3 +++ 5 files changed, 4 insertions(+), 12 deletions(-) (limited to 'arch') diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c index 6df395fff971..f5dfddf492e2 100644 --- a/arch/arm/mach-omap2/pm34xx.c +++ b/arch/arm/mach-omap2/pm34xx.c @@ -298,11 +298,7 @@ static void omap3_pm_idle(void) if (omap_irq_pending()) return; - trace_cpu_idle_rcuidle(1, smp_processor_id()); - omap_sram_idle(); - - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #ifdef CONFIG_SUSPEND diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index b63ce4c54cfe..f1804496b935 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -123,10 +123,8 @@ void arch_cpu_idle(void) * This should do all the clock switching and wait for interrupt * tricks */ - trace_cpu_idle_rcuidle(1, smp_processor_id()); cpu_do_idle(); local_irq_enable(); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #ifdef CONFIG_HOTPLUG_CPU diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c index 88bb42ca5008..c73f50649e7e 100644 --- a/arch/s390/kernel/idle.c +++ b/arch/s390/kernel/idle.c @@ -33,14 +33,13 @@ void enabled_wait(void) PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; clear_cpu_flag(CIF_NOHZ_DELAY); - trace_cpu_idle_rcuidle(1, smp_processor_id()); local_irq_save(flags); /* Call the assembler magic in entry.S */ psw_idle(idle, psw_mask); local_irq_restore(flags); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); /* Account time spent with enabled wait psw loaded as idle time. */ + /* XXX seqcount has tracepoints that require RCU */ write_seqcount_begin(&idle->seqcount); idle_time = idle->clock_idle_exit - idle->clock_idle_enter; idle->clock_idle_enter = idle->clock_idle_exit = 0ULL; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 994d8393f2f7..13ce616cc7af 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -684,9 +684,7 @@ void arch_cpu_idle(void) */ void __cpuidle default_idle(void) { - trace_cpu_idle_rcuidle(1, smp_processor_id()); safe_halt(); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE) EXPORT_SYMBOL(default_idle); @@ -792,7 +790,6 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c) static __cpuidle void mwait_idle(void) { if (!current_set_polling_and_test()) { - trace_cpu_idle_rcuidle(1, smp_processor_id()); if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) { mb(); /* quirk */ clflush((void *)¤t_thread_info()->flags); @@ -804,7 +801,6 @@ static __cpuidle void mwait_idle(void) __sti_mwait(0, 0); else local_irq_enable(); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } else { local_irq_enable(); } diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index ea3a0989dc4c..f324dc36fc43 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -91,11 +91,14 @@ void __cpuidle default_idle_call(void) if (current_clr_polling_and_test()) { local_irq_enable(); } else { + + trace_cpu_idle(1, smp_processor_id()); stop_critical_timings(); rcu_idle_enter(); arch_cpu_idle(); rcu_idle_exit(); start_critical_timings(); + trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); } } -- cgit v1.2.3 From 7da93f379330f2be1122ca7f54ab1eb44ef9aa59 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 12 Aug 2020 19:28:07 +0200 Subject: x86/entry: Remove unused THUNKs Unused remnants Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.487040689@infradead.org --- arch/x86/entry/thunk_32.S | 5 ----- 1 file changed, 5 deletions(-) (limited to 'arch') diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S index 3a07ce3ec70b..f1f96d4d8cd6 100644 --- a/arch/x86/entry/thunk_32.S +++ b/arch/x86/entry/thunk_32.S @@ -29,11 +29,6 @@ SYM_CODE_START_NOALIGN(\name) SYM_CODE_END(\name) .endm -#ifdef CONFIG_TRACE_IRQFLAGS - THUNK trace_hardirqs_on_thunk,trace_hardirqs_on_caller,1 - THUNK trace_hardirqs_off_thunk,trace_hardirqs_off_caller,1 -#endif - #ifdef CONFIG_PREEMPTION THUNK preempt_schedule_thunk, preempt_schedule THUNK preempt_schedule_notrace_thunk, preempt_schedule_notrace -- cgit v1.2.3 From 36206b588bc815e5f64e8da72d7ab79e00b76281 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 20 Aug 2020 09:27:52 +0200 Subject: nds32: Implement arch_irqs_disabled() Cc: Nick Hu Cc: Greentime Hu Cc: Vincent Chen Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.604899379@infradead.org --- arch/nds32/include/asm/irqflags.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch') diff --git a/arch/nds32/include/asm/irqflags.h b/arch/nds32/include/asm/irqflags.h index fb45ec46bb1b..51ef800bb301 100644 --- a/arch/nds32/include/asm/irqflags.h +++ b/arch/nds32/include/asm/irqflags.h @@ -34,3 +34,8 @@ static inline int arch_irqs_disabled_flags(unsigned long flags) { return !flags; } + +static inline int arch_irqs_disabled(void) +{ + return arch_irqs_disabled_flags(arch_local_save_flags()); +} -- cgit v1.2.3 From 021c109330ebc1f54b546c63a078ea3c31356ecb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 Aug 2020 10:40:49 +0200 Subject: arm64: Implement arch_irqs_disabled() Cc: Catalin Marinas Cc: Will Deacon Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Link: https://lkml.kernel.org/r/20200821085348.664425120@infradead.org --- arch/arm64/include/asm/irqflags.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch') diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h index aa4b6521ef14..ff328e5bbb75 100644 --- a/arch/arm64/include/asm/irqflags.h +++ b/arch/arm64/include/asm/irqflags.h @@ -95,6 +95,11 @@ static inline int arch_irqs_disabled_flags(unsigned long flags) return res; } +static inline int arch_irqs_disabled(void) +{ + return arch_irqs_disabled_flags(arch_local_save_flags()); +} + static inline unsigned long arch_local_irq_save(void) { unsigned long flags; -- cgit v1.2.3 From 99dc56feb7932020502d40107a712fa302b32082 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 22 Aug 2020 18:04:15 +0200 Subject: mips: Implement arch_irqs_disabled() Cc: Thomas Bogendoerfer Cc: Paul Burton Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200826101653.GE1362448@hirez.programming.kicks-ass.net --- arch/mips/include/asm/irqflags.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch') diff --git a/arch/mips/include/asm/irqflags.h b/arch/mips/include/asm/irqflags.h index 47a8ffc0b413..f5b8300f4573 100644 --- a/arch/mips/include/asm/irqflags.h +++ b/arch/mips/include/asm/irqflags.h @@ -137,6 +137,11 @@ static inline int arch_irqs_disabled_flags(unsigned long flags) return !(flags & 1); } +static inline int arch_irqs_disabled(void) +{ + return arch_irqs_disabled_flags(arch_local_save_flags()); +} + #endif /* #ifndef __ASSEMBLY__ */ /* -- cgit v1.2.3 From 044d0d6de9f50192f9697583504a382347ee95ca Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 23 Jul 2020 20:56:14 +1000 Subject: lockdep: Only trace IRQ edges Problem: raw_local_irq_save(); // software state on local_irq_save(); // software state off ... local_irq_restore(); // software state still off, because we don't enable IRQs raw_local_irq_restore(); // software state still off, *whoopsie* existing instances: - lock_acquire() raw_local_irq_save() __lock_acquire() arch_spin_lock(&graph_lock) pv_wait() := kvm_wait() (same or worse for Xen/HyperV) local_irq_save() - trace_clock_global() raw_local_irq_save() arch_spin_lock() pv_wait() := kvm_wait() local_irq_save() - apic_retrigger_irq() raw_local_irq_save() apic->send_IPI() := default_send_IPI_single_phys() local_irq_save() Possible solutions: A) make it work by enabling the tracing inside raw_*() B) make it work by keeping tracing disabled inside raw_*() C) call it broken and clean it up now Now, given that the only reason to use the raw_* variant is because you don't want tracing. Therefore A) seems like a weird option (although it can be done). C) is tempting, but OTOH it ends up converting a _lot_ of code to raw just because there is one raw user, this strips the validation/tracing off for all the other users. So we pick B) and declare any code that ends up doing: raw_local_irq_save() local_irq_save() lockdep_assert_irqs_disabled(); broken. AFAICT this problem has existed forever, the only reason it came up is because commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ state tracking") changed IRQ tracing vs lockdep recursion and the first instance is fairly common, the other cases hardly ever happen. Signed-off-by: Nicholas Piggin [rewrote changelog] Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200723105615.1268126-1-npiggin@gmail.com --- arch/powerpc/include/asm/hw_irq.h | 11 ++++------- include/linux/irqflags.h | 15 +++++++-------- 2 files changed, 11 insertions(+), 15 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index 3a0db7b0b46e..35060be09073 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void) #define powerpc_local_irq_pmu_save(flags) \ do { \ raw_local_irq_pmu_save(flags); \ - trace_hardirqs_off(); \ + if (!raw_irqs_disabled_flags(flags)) \ + trace_hardirqs_off(); \ } while(0) #define powerpc_local_irq_pmu_restore(flags) \ do { \ - if (raw_irqs_disabled_flags(flags)) { \ - raw_local_irq_pmu_restore(flags); \ - trace_hardirqs_off(); \ - } else { \ + if (!raw_irqs_disabled_flags(flags)) \ trace_hardirqs_on(); \ - raw_local_irq_pmu_restore(flags); \ - } \ + raw_local_irq_pmu_restore(flags); \ } while(0) #else #define powerpc_local_irq_pmu_save(flags) \ diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 00d553d77911..3ed4e8771b64 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -191,25 +191,24 @@ do { \ #define local_irq_disable() \ do { \ + bool was_disabled = raw_irqs_disabled();\ raw_local_irq_disable(); \ - trace_hardirqs_off(); \ + if (!was_disabled) \ + trace_hardirqs_off(); \ } while (0) #define local_irq_save(flags) \ do { \ raw_local_irq_save(flags); \ - trace_hardirqs_off(); \ + if (!raw_irqs_disabled_flags(flags)) \ + trace_hardirqs_off(); \ } while (0) #define local_irq_restore(flags) \ do { \ - if (raw_irqs_disabled_flags(flags)) { \ - raw_local_irq_restore(flags); \ - trace_hardirqs_off(); \ - } else { \ + if (!raw_irqs_disabled_flags(flags)) \ trace_hardirqs_on(); \ - raw_local_irq_restore(flags); \ - } \ + raw_local_irq_restore(flags); \ } while (0) #define safe_halt() \ -- cgit v1.2.3