diff options
author | Peter Zijlstra <peterz@infradead.org> | 2020-05-27 15:50:29 +0200 |
---|---|---|
committer | Peter Zijlstra <peterz@infradead.org> | 2020-07-10 12:00:01 +0200 |
commit | ba1f2b2eaa2a529dba722507c55ff3d761d325dd (patch) | |
tree | d46ece3c91564b177457203613c172059cae4cc0 | |
parent | 859d069ee1ddd87862e1d6a356a82ed417dbeb67 (diff) |
x86/entry: Fix NMI vs IRQ state tracking
While the nmi_enter() users did
trace_hardirqs_{off_prepare,on_finish}() there was no matching
lockdep_hardirqs_*() calls to complete the picture.
Introduce idtentry_{enter,exit}_nmi() to enable proper IRQ state
tracking across the NMIs.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
-rw-r--r-- | arch/x86/entry/common.c | 42 | ||||
-rw-r--r-- | arch/x86/include/asm/idtentry.h | 3 | ||||
-rw-r--r-- | arch/x86/kernel/nmi.c | 9 | ||||
-rw-r--r-- | arch/x86/kernel/traps.c | 17 | ||||
-rw-r--r-- | include/linux/hardirq.h | 28 |
5 files changed, 70 insertions, 29 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 0521546022cb..63c607dd6c52 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -592,7 +592,7 @@ SYSCALL_DEFINE0(ni_syscall) * The return value must be fed into the state argument of * idtentry_exit(). */ -idtentry_state_t noinstr idtentry_enter(struct pt_regs *regs) +noinstr idtentry_state_t idtentry_enter(struct pt_regs *regs) { idtentry_state_t ret = { .exit_rcu = false, @@ -687,7 +687,7 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) * Counterpart to idtentry_enter(). The return value of the entry * function must be fed into the @state argument. */ -void noinstr idtentry_exit(struct pt_regs *regs, idtentry_state_t state) +noinstr void idtentry_exit(struct pt_regs *regs, idtentry_state_t state) { lockdep_assert_irqs_disabled(); @@ -731,7 +731,7 @@ void noinstr idtentry_exit(struct pt_regs *regs, idtentry_state_t state) * Invokes enter_from_user_mode() to establish the proper context for * NOHZ_FULL. Otherwise scheduling on exit would not be possible. */ -void noinstr idtentry_enter_user(struct pt_regs *regs) +noinstr void idtentry_enter_user(struct pt_regs *regs) { check_user_regs(regs); enter_from_user_mode(); @@ -749,13 +749,47 @@ void noinstr idtentry_enter_user(struct pt_regs *regs) * * Counterpart to idtentry_enter_user(). */ -void noinstr idtentry_exit_user(struct pt_regs *regs) +noinstr void idtentry_exit_user(struct pt_regs *regs) { lockdep_assert_irqs_disabled(); prepare_exit_to_usermode(regs); } +noinstr bool idtentry_enter_nmi(struct pt_regs *regs) +{ + bool irq_state = lockdep_hardirqs_enabled(current); + + __nmi_enter(); + lockdep_hardirqs_off(CALLER_ADDR0); + lockdep_hardirq_enter(); + rcu_nmi_enter(); + + instrumentation_begin(); + trace_hardirqs_off_finish(); + ftrace_nmi_enter(); + instrumentation_end(); + + return irq_state; +} + +noinstr void idtentry_exit_nmi(struct pt_regs *regs, bool restore) +{ + instrumentation_begin(); + ftrace_nmi_exit(); + if (restore) { + trace_hardirqs_on_prepare(); + lockdep_hardirqs_on_prepare(CALLER_ADDR0); + } + instrumentation_end(); + + rcu_nmi_exit(); + lockdep_hardirq_exit(); + if (restore) + lockdep_hardirqs_on(CALLER_ADDR0); + __nmi_exit(); +} + #ifdef CONFIG_XEN_PV #ifndef CONFIG_PREEMPTION /* diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 7227225cf45d..2b0497486525 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -20,6 +20,9 @@ typedef struct idtentry_state { idtentry_state_t idtentry_enter(struct pt_regs *regs); void idtentry_exit(struct pt_regs *regs, idtentry_state_t state); +bool idtentry_enter_nmi(struct pt_regs *regs); +void idtentry_exit_nmi(struct pt_regs *regs, bool irq_state); + /** * DECLARE_IDTENTRY - Declare functions for simple IDT entry points * No error code pushed by hardware diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index d7c5e44b26f7..4fc9954a9560 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -330,7 +330,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs) __this_cpu_write(last_nmi_rip, regs->ip); instrumentation_begin(); - trace_hardirqs_off_finish(); handled = nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); @@ -417,8 +416,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs) unknown_nmi_error(reason, regs); out: - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); } @@ -478,6 +475,8 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7); DEFINE_IDTENTRY_RAW(exc_nmi) { + bool irq_state; + if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id())) return; @@ -491,14 +490,14 @@ nmi_restart: this_cpu_write(nmi_dr7, local_db_save()); - nmi_enter(); + irq_state = idtentry_enter_nmi(regs); inc_irq_stat(__nmi_count); if (!ignore_nmis) default_do_nmi(regs); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); local_db_restore(this_cpu_read(nmi_dr7)); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 4627f826fb57..cdd73829e637 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -403,7 +403,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault) } #endif - nmi_enter(); + idtentry_enter_nmi(regs); instrumentation_begin(); notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); @@ -649,15 +649,12 @@ DEFINE_IDTENTRY_RAW(exc_int3) instrumentation_end(); idtentry_exit_user(regs); } else { - nmi_enter(); + bool irq_state = idtentry_enter_nmi(regs); instrumentation_begin(); - trace_hardirqs_off_finish(); if (!do_int3(regs)) die("int3", regs, 0); - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); } } @@ -865,9 +862,8 @@ out: static __always_inline void exc_debug_kernel(struct pt_regs *regs, unsigned long dr6) { - nmi_enter(); + bool irq_state = idtentry_enter_nmi(regs); instrumentation_begin(); - trace_hardirqs_off_finish(); /* * If something gets miswired and we end up here for a user mode @@ -884,10 +880,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, handle_debug(regs, dr6, false); - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); } static __always_inline void exc_debug_user(struct pt_regs *regs, @@ -903,6 +897,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, instrumentation_begin(); handle_debug(regs, dr6, true); + instrumentation_end(); idtentry_exit_user(regs); } diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 03c9fece7d43..754f67ac4326 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -111,32 +111,42 @@ extern void rcu_nmi_exit(void); /* * nmi_enter() can nest up to 15 times; see NMI_BITS. */ -#define nmi_enter() \ +#define __nmi_enter() \ do { \ + lockdep_off(); \ arch_nmi_enter(); \ printk_nmi_enter(); \ - lockdep_off(); \ BUG_ON(in_nmi() == NMI_MASK); \ __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \ - rcu_nmi_enter(); \ + } while (0) + +#define nmi_enter() \ + do { \ + __nmi_enter(); \ lockdep_hardirq_enter(); \ + rcu_nmi_enter(); \ instrumentation_begin(); \ ftrace_nmi_enter(); \ instrumentation_end(); \ } while (0) +#define __nmi_exit() \ + do { \ + BUG_ON(!in_nmi()); \ + __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ + printk_nmi_exit(); \ + arch_nmi_exit(); \ + lockdep_on(); \ + } while (0) + #define nmi_exit() \ do { \ instrumentation_begin(); \ ftrace_nmi_exit(); \ instrumentation_end(); \ - lockdep_hardirq_exit(); \ rcu_nmi_exit(); \ - BUG_ON(!in_nmi()); \ - __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ - lockdep_on(); \ - printk_nmi_exit(); \ - arch_nmi_exit(); \ + lockdep_hardirq_exit(); \ + __nmi_exit(); \ } while (0) #endif /* LINUX_HARDIRQ_H */ |