diff options
Diffstat (limited to 'arch/x86/entry/common.c')
| -rw-r--r-- | arch/x86/entry/common.c | 88 |
1 files changed, 64 insertions, 24 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index f09288431f28..54ad1890aefc 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -559,8 +559,7 @@ SYSCALL_DEFINE0(ni_syscall) } /** - * idtentry_enter_cond_rcu - Handle state tracking on idtentry with conditional - * RCU handling + * idtentry_enter - Handle state tracking on ordinary idtentries * @regs: Pointer to pt_regs of interrupted context * * Invokes: @@ -572,6 +571,9 @@ SYSCALL_DEFINE0(ni_syscall) * - The hardirq tracer to keep the state consistent as low level ASM * entry disabled interrupts. * + * As a precondition, this requires that the entry came from user mode, + * idle, or a kernel context in which RCU is watching. + * * For kernel mode entries RCU handling is done conditional. If RCU is * watching then the only RCU requirement is to check whether the tick has * to be restarted. If RCU is not watching then rcu_irq_enter() has to be @@ -585,18 +587,21 @@ SYSCALL_DEFINE0(ni_syscall) * establish the proper context for NOHZ_FULL. Otherwise scheduling on exit * would not be possible. * - * Returns: True if RCU has been adjusted on a kernel entry - * False otherwise + * Returns: An opaque object that must be passed to idtentry_exit() * - * The return value must be fed into the rcu_exit argument of - * idtentry_exit_cond_rcu(). + * The return value must be fed into the state argument of + * idtentry_exit(). */ -bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) +noinstr idtentry_state_t idtentry_enter(struct pt_regs *regs) { + idtentry_state_t ret = { + .exit_rcu = false, + }; + if (user_mode(regs)) { check_user_regs(regs); enter_from_user_mode(); - return false; + return ret; } /* @@ -634,7 +639,8 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) trace_hardirqs_off_finish(); instrumentation_end(); - return true; + ret.exit_rcu = true; + return ret; } /* @@ -649,7 +655,7 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) trace_hardirqs_off(); instrumentation_end(); - return false; + return ret; } static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) @@ -667,10 +673,9 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) } /** - * idtentry_exit_cond_rcu - Handle return from exception with conditional RCU - * handling + * idtentry_exit - Handle return from exception that used idtentry_enter() * @regs: Pointer to pt_regs (exception entry regs) - * @rcu_exit: Invoke rcu_irq_exit() if true + * @state: Return value from matching call to idtentry_enter() * * Depending on the return target (kernel/user) this runs the necessary * preemption and work checks if possible and reguired and returns to @@ -679,10 +684,10 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) * This is the last action before returning to the low level ASM code which * just needs to return to the appropriate context. * - * Counterpart to idtentry_enter_cond_rcu(). The return value of the entry - * function must be fed into the @rcu_exit argument. + * Counterpart to idtentry_enter(). The return value of the entry + * function must be fed into the @state argument. */ -void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) +noinstr void idtentry_exit(struct pt_regs *regs, idtentry_state_t state) { lockdep_assert_irqs_disabled(); @@ -695,7 +700,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) * carefully and needs the same ordering of lockdep/tracing * and RCU as the return to user mode path. */ - if (rcu_exit) { + if (state.exit_rcu) { instrumentation_begin(); /* Tell the tracer that IRET will enable interrupts */ trace_hardirqs_on_prepare(); @@ -714,7 +719,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) * IRQ flags state is correct already. Just tell RCU if it * was not watching on entry. */ - if (rcu_exit) + if (state.exit_rcu) rcu_irq_exit(); } } @@ -726,7 +731,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) * 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(); @@ -744,13 +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(); + + __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 /* @@ -800,9 +839,10 @@ static void __xen_pv_evtchn_do_upcall(void) __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) { struct pt_regs *old_regs; - bool inhcall, rcu_exit; + bool inhcall; + idtentry_state_t state; - rcu_exit = idtentry_enter_cond_rcu(regs); + state = idtentry_enter(regs); old_regs = set_irq_regs(regs); instrumentation_begin(); @@ -812,13 +852,13 @@ __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) set_irq_regs(old_regs); inhcall = get_and_clear_inhcall(); - if (inhcall && !WARN_ON_ONCE(rcu_exit)) { + if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) { instrumentation_begin(); idtentry_exit_cond_resched(regs, true); instrumentation_end(); restore_inhcall(inhcall); } else { - idtentry_exit_cond_rcu(regs, rcu_exit); + idtentry_exit(regs, state); } } #endif /* CONFIG_XEN_PV */ |