diff options
Diffstat (limited to 'include/linux/entry-common.h')
| -rw-r--r-- | include/linux/entry-common.h | 171 |
1 files changed, 131 insertions, 40 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 474f29638d2c..7c581a4c3797 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -13,22 +13,6 @@ * Define dummy _TIF work flags if not defined by the architecture or for * disabled functionality. */ -#ifndef _TIF_SYSCALL_EMU -# define _TIF_SYSCALL_EMU (0) -#endif - -#ifndef _TIF_SYSCALL_TRACEPOINT -# define _TIF_SYSCALL_TRACEPOINT (0) -#endif - -#ifndef _TIF_SECCOMP -# define _TIF_SECCOMP (0) -#endif - -#ifndef _TIF_SYSCALL_AUDIT -# define _TIF_SYSCALL_AUDIT (0) -#endif - #ifndef _TIF_PATCH_PENDING # define _TIF_PATCH_PENDING (0) #endif @@ -37,28 +21,36 @@ # define _TIF_UPROBE (0) #endif +#ifndef _TIF_NOTIFY_SIGNAL +# define _TIF_NOTIFY_SIGNAL (0) +#endif + /* - * TIF flags handled in syscall_enter_from_user_mode() + * SYSCALL_WORK flags handled in syscall_enter_from_user_mode() */ -#ifndef ARCH_SYSCALL_ENTER_WORK -# define ARCH_SYSCALL_ENTER_WORK (0) +#ifndef ARCH_SYSCALL_WORK_ENTER +# define ARCH_SYSCALL_WORK_ENTER (0) #endif -#define SYSCALL_ENTER_WORK \ - (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ - _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \ - ARCH_SYSCALL_ENTER_WORK) - /* - * TIF flags handled in syscall_exit_to_user_mode() + * SYSCALL_WORK flags handled in syscall_exit_to_user_mode() */ -#ifndef ARCH_SYSCALL_EXIT_WORK -# define ARCH_SYSCALL_EXIT_WORK (0) +#ifndef ARCH_SYSCALL_WORK_EXIT +# define ARCH_SYSCALL_WORK_EXIT (0) #endif -#define SYSCALL_EXIT_WORK \ - (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ - _TIF_SYSCALL_TRACEPOINT | ARCH_SYSCALL_EXIT_WORK) +#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \ + SYSCALL_WORK_SYSCALL_TRACEPOINT | \ + SYSCALL_WORK_SYSCALL_TRACE | \ + SYSCALL_WORK_SYSCALL_EMU | \ + SYSCALL_WORK_SYSCALL_AUDIT | \ + SYSCALL_WORK_SYSCALL_USER_DISPATCH | \ + ARCH_SYSCALL_WORK_ENTER) +#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \ + SYSCALL_WORK_SYSCALL_TRACE | \ + SYSCALL_WORK_SYSCALL_AUDIT | \ + SYSCALL_WORK_SYSCALL_USER_DISPATCH | \ + ARCH_SYSCALL_WORK_EXIT) /* * TIF flags handled in exit_to_user_mode_loop() @@ -69,7 +61,7 @@ #define EXIT_TO_USER_MODE_WORK \ (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ - _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | \ + _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \ ARCH_EXIT_TO_USER_MODE_WORK) /** @@ -110,6 +102,27 @@ static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs #endif /** + * enter_from_user_mode - Establish state when coming from user mode + * + * Syscall/interrupt entry disables interrupts, but user mode is traced as + * interrupts enabled. Also with NO_HZ_FULL RCU might be idle. + * + * 1) Tell lockdep that interrupts are disabled + * 2) Invoke context tracking if enabled to reactivate RCU + * 3) Trace interrupts off state + * + * Invoked from architecture specific syscall entry code with interrupts + * disabled. The calling code has to be non-instrumentable. When the + * function returns all state is correct and interrupts are still + * disabled. The subsequent functions can be instrumented. + * + * This is invoked when there is architecture specific functionality to be + * done between establishing state and enabling interrupts. The caller must + * enable interrupts before invoking syscall_enter_from_user_mode_work(). + */ +void enter_from_user_mode(struct pt_regs *regs); + +/** * syscall_enter_from_user_mode_prepare - Establish state and enable interrupts * @regs: Pointer to currents pt_regs * @@ -118,7 +131,8 @@ static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs * function returns all state is correct, interrupts are enabled and the * subsequent functions can be instrumented. * - * This handles lockdep, RCU (context tracking) and tracing state. + * This handles lockdep, RCU (context tracking) and tracing state, i.e. + * the functionality provided by enter_from_user_mode(). * * This is invoked when there is extra architecture specific functionality * to be done between establishing state and handling user mode entry work. @@ -144,8 +158,8 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs); * * It handles the following work items: * - * 1) TIF flag dependent invocations of arch_syscall_enter_tracehook(), - * __secure_computing(), trace_sys_enter() + * 1) syscall_work flag dependent invocations of + * arch_syscall_enter_tracehook(), __secure_computing(), trace_sys_enter() * 2) Invocation of audit_syscall_entry() */ long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall); @@ -259,12 +273,13 @@ static __always_inline void arch_exit_to_user_mode(void) { } #endif /** - * arch_do_signal - Architecture specific signal delivery function + * arch_do_signal_or_restart - Architecture specific signal delivery function * @regs: Pointer to currents pt_regs + * @has_signal: actual signal to handle * * Invoked from exit_to_user_mode_loop(). */ -void arch_do_signal(struct pt_regs *regs); +void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal); /** * arch_syscall_exit_tracehook - Wrapper around tracehook_report_syscall_exit() @@ -286,6 +301,41 @@ static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step) #endif /** + * exit_to_user_mode - Fixup state when exiting to user mode + * + * Syscall/interrupt exit enables interrupts, but the kernel state is + * interrupts disabled when this is invoked. Also tell RCU about it. + * + * 1) Trace interrupts on state + * 2) Invoke context tracking if enabled to adjust RCU state + * 3) Invoke architecture specific last minute exit code, e.g. speculation + * mitigations, etc.: arch_exit_to_user_mode() + * 4) Tell lockdep that interrupts are enabled + * + * Invoked from architecture specific code when syscall_exit_to_user_mode() + * is not suitable as the last step before returning to userspace. Must be + * invoked with interrupts disabled and the caller must be + * non-instrumentable. + * The caller has to invoke syscall_exit_to_user_mode_work() before this. + */ +void exit_to_user_mode(void); + +/** + * syscall_exit_to_user_mode_work - Handle work before returning to user mode + * @regs: Pointer to currents pt_regs + * + * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling + * exit_to_user_mode() to perform the final transition to user mode. + * + * Calling convention is the same as for syscall_exit_to_user_mode() and it + * returns with all work handled and interrupts disabled. The caller must + * invoke exit_to_user_mode() before actually switching to user mode to + * make the final state transitions. Interrupts must stay disabled between + * return from this function and the invocation of exit_to_user_mode(). + */ +void syscall_exit_to_user_mode_work(struct pt_regs *regs); + +/** * syscall_exit_to_user_mode - Handle work before returning to user mode * @regs: Pointer to currents pt_regs * @@ -307,8 +357,12 @@ static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step) * - Architecture specific one time work arch_exit_to_user_mode_prepare() * - Address limit and lockdep checks * - * 3) Final transition (lockdep, tracing, context tracking, RCU). Invokes - * arch_exit_to_user_mode() to handle e.g. speculation mitigations + * 3) Final transition (lockdep, tracing, context tracking, RCU), i.e. the + * functionality in exit_to_user_mode(). + * + * This is a combination of syscall_exit_to_user_mode_work() (1,2) and + * exit_to_user_mode(). This function is preferred unless there is a + * compelling architectural reason to use the seperate functions. */ void syscall_exit_to_user_mode(struct pt_regs *regs); @@ -341,8 +395,26 @@ void irqentry_enter_from_user_mode(struct pt_regs *regs); void irqentry_exit_to_user_mode(struct pt_regs *regs); #ifndef irqentry_state +/** + * struct irqentry_state - Opaque object for exception state storage + * @exit_rcu: Used exclusively in the irqentry_*() calls; signals whether the + * exit path has to invoke rcu_irq_exit(). + * @lockdep: Used exclusively in the irqentry_nmi_*() calls; ensures that + * lockdep state is restored correctly on exit from nmi. + * + * This opaque object is filled in by the irqentry_*_enter() functions and + * must be passed back into the corresponding irqentry_*_exit() functions + * when the exception is complete. + * + * Callers of irqentry_*_[enter|exit]() must consider this structure opaque + * and all members private. Descriptions of the members are provided to aid in + * the maintenance of the irqentry_*() functions. + */ typedef struct irqentry_state { - bool exit_rcu; + union { + bool exit_rcu; + bool lockdep; + }; } irqentry_state_t; #endif @@ -392,7 +464,7 @@ void irqentry_exit_cond_resched(void); * @state: Return value from matching call to irqentry_enter() * * Depending on the return target (kernel/user) this runs the necessary - * preemption and work checks if possible and reguired and returns to + * preemption and work checks if possible and required and returns to * the caller with interrupts disabled and no further work pending. * * This is the last action before returning to the low level ASM code which @@ -402,4 +474,23 @@ void irqentry_exit_cond_resched(void); */ void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state); +/** + * irqentry_nmi_enter - Handle NMI entry + * @regs: Pointer to currents pt_regs + * + * Similar to irqentry_enter() but taking care of the NMI constraints. + */ +irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs); + +/** + * irqentry_nmi_exit - Handle return from NMI handling + * @regs: Pointer to pt_regs (NMI entry regs) + * @irq_state: Return value from matching call to irqentry_nmi_enter() + * + * Last action before returning to the low level assembly code. + * + * Counterpart to irqentry_nmi_enter(). + */ +void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state); + #endif |