diff options
Diffstat (limited to 'include/linux/tracepoint.h')
| -rw-r--r-- | include/linux/tracepoint.h | 169 |
1 files changed, 96 insertions, 73 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 93a9f3070b48..425123e921ac 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -17,6 +17,7 @@ #include <linux/errno.h> #include <linux/types.h> #include <linux/rcupdate.h> +#include <linux/rcupdate_trace.h> #include <linux/tracepoint-defs.h> #include <linux/static_call.h> @@ -32,8 +33,6 @@ struct trace_eval_map { #define TRACEPOINT_DEFAULT_PRIO 10 -extern struct srcu_struct tracepoint_srcu; - extern int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data); extern int @@ -105,16 +104,30 @@ void for_each_tracepoint_in_module(struct module *mod, * tracepoint_synchronize_unregister must be called between the last tracepoint * probe unregistration and the end of module exit to make sure there is no * caller executing a probe when it is freed. + * + * An alternative is to use the following for batch reclaim associated + * with a given tracepoint: + * + * - tracepoint_is_faultable() == false: call_rcu() + * - tracepoint_is_faultable() == true: call_rcu_tasks_trace() */ #ifdef CONFIG_TRACEPOINTS static inline void tracepoint_synchronize_unregister(void) { - synchronize_srcu(&tracepoint_srcu); + synchronize_rcu_tasks_trace(); synchronize_rcu(); } +static inline bool tracepoint_is_faultable(struct tracepoint *tp) +{ + return tp->ext && tp->ext->faultable; +} #else static inline void tracepoint_synchronize_unregister(void) { } +static inline bool tracepoint_is_faultable(struct tracepoint *tp) +{ + return false; +} #endif #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS @@ -197,66 +210,35 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #endif /* CONFIG_HAVE_STATIC_CALL */ /* - * ARCH_WANTS_NO_INSTR archs are expected to have sanitized entry and idle - * code that disallow any/all tracing/instrumentation when RCU isn't watching. - */ -#ifdef CONFIG_ARCH_WANTS_NO_INSTR -#define RCUIDLE_COND(rcuidle) (rcuidle) -#else -/* srcu can't be used from NMI */ -#define RCUIDLE_COND(rcuidle) (rcuidle && in_nmi()) -#endif - -/* * it_func[0] is never NULL because there is at least one element in the array * when the array itself is non NULL. + * + * With @syscall=0, the tracepoint callback array dereference is + * protected by disabling preemption. + * With @syscall=1, the tracepoint callback array dereference is + * protected by Tasks Trace RCU, which allows probes to handle page + * faults. */ -#define __DO_TRACE(name, args, cond, rcuidle) \ +#define __DO_TRACE(name, args, cond, syscall) \ do { \ int __maybe_unused __idx = 0; \ \ if (!(cond)) \ return; \ \ - if (WARN_ONCE(RCUIDLE_COND(rcuidle), \ - "Bad RCU usage for tracepoint")) \ - return; \ - \ - /* keep srcu and sched-rcu usage consistent */ \ - preempt_disable_notrace(); \ - \ - /* \ - * For rcuidle callers, use srcu since sched-rcu \ - * doesn't work from the idle path. \ - */ \ - if (rcuidle) { \ - __idx = srcu_read_lock_notrace(&tracepoint_srcu);\ - ct_irq_enter_irqson(); \ - } \ + if (syscall) \ + rcu_read_lock_trace(); \ + else \ + preempt_disable_notrace(); \ \ __DO_TRACE_CALL(name, TP_ARGS(args)); \ \ - if (rcuidle) { \ - ct_irq_exit_irqson(); \ - srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\ - } \ - \ - preempt_enable_notrace(); \ + if (syscall) \ + rcu_read_unlock_trace(); \ + else \ + preempt_enable_notrace(); \ } while (0) -#ifndef MODULE -#define __DECLARE_TRACE_RCU(name, proto, args, cond) \ - static inline void trace_##name##_rcuidle(proto) \ - { \ - if (static_key_false(&__tracepoint_##name.key)) \ - __DO_TRACE(name, \ - TP_ARGS(args), \ - TP_CONDITION(cond), 1); \ - } -#else -#define __DECLARE_TRACE_RCU(name, proto, args, cond) -#endif - /* * Make sure the alignment of the structure in the __tracepoints section will * not add unwanted padding between the beginning of the section and the @@ -268,23 +250,10 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * site if it is not watching, as it will need to be active when the * tracepoint is enabled. */ -#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ +#define __DECLARE_TRACE_COMMON(name, proto, args, cond, data_proto) \ extern int __traceiter_##name(data_proto); \ DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ extern struct tracepoint __tracepoint_##name; \ - static inline void trace_##name(proto) \ - { \ - if (static_key_false(&__tracepoint_##name.key)) \ - __DO_TRACE(name, \ - TP_ARGS(args), \ - TP_CONDITION(cond), 0); \ - if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ - WARN_ONCE(!rcu_is_watching(), \ - "RCU not watching for tracepoint"); \ - } \ - } \ - __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ - PARAMS(cond)) \ static inline int \ register_trace_##name(void (*probe)(data_proto), void *data) \ { \ @@ -311,7 +280,36 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) static inline bool \ trace_##name##_enabled(void) \ { \ - return static_key_false(&__tracepoint_##name.key); \ + return static_branch_unlikely(&__tracepoint_##name.key);\ + } + +#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ + static inline void trace_##name(proto) \ + { \ + if (static_branch_unlikely(&__tracepoint_##name.key)) \ + __DO_TRACE(name, \ + TP_ARGS(args), \ + TP_CONDITION(cond), 0); \ + if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ + WARN_ONCE(!rcu_is_watching(), \ + "RCU not watching for tracepoint"); \ + } \ + } + +#define __DECLARE_TRACE_SYSCALL(name, proto, args, cond, data_proto) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ + static inline void trace_##name(proto) \ + { \ + might_fault(); \ + if (static_branch_unlikely(&__tracepoint_##name.key)) \ + __DO_TRACE(name, \ + TP_ARGS(args), \ + TP_CONDITION(cond), 1); \ + if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ + WARN_ONCE(!rcu_is_watching(), \ + "RCU not watching for tracepoint"); \ + } \ } /* @@ -319,7 +317,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * structures, so we create an array of pointers that will be used for iteration * on the tracepoints. */ -#define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args) \ +#define __DEFINE_TRACE_EXT(_name, _ext, proto, args) \ static const char __tpstrtab_##_name[] \ __section("__tracepoints_strings") = #_name; \ extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \ @@ -328,14 +326,14 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) struct tracepoint __tracepoint_##_name __used \ __section("__tracepoints") = { \ .name = __tpstrtab_##_name, \ - .key = STATIC_KEY_INIT_FALSE, \ + .key = STATIC_KEY_FALSE_INIT, \ .static_call_key = &STATIC_CALL_KEY(tp_func_##_name), \ .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \ .iterator = &__traceiter_##_name, \ .probestub = &__probestub_##_name, \ - .regfunc = _reg, \ - .unregfunc = _unreg, \ - .funcs = NULL }; \ + .funcs = NULL, \ + .ext = _ext, \ + }; \ __TRACEPOINT_ENTRY(_name); \ int __traceiter_##_name(void *__data, proto) \ { \ @@ -358,8 +356,24 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) } \ DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); -#define DEFINE_TRACE(name, proto, args) \ - DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); +#define DEFINE_TRACE_FN(_name, _reg, _unreg, _proto, _args) \ + static struct tracepoint_ext __tracepoint_ext_##_name = { \ + .regfunc = _reg, \ + .unregfunc = _unreg, \ + .faultable = false, \ + }; \ + __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); + +#define DEFINE_TRACE_SYSCALL(_name, _reg, _unreg, _proto, _args) \ + static struct tracepoint_ext __tracepoint_ext_##_name = { \ + .regfunc = _reg, \ + .unregfunc = _unreg, \ + .faultable = true, \ + }; \ + __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); + +#define DEFINE_TRACE(_name, _proto, _args) \ + __DEFINE_TRACE_EXT(_name, NULL, PARAMS(_proto), PARAMS(_args)); #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ EXPORT_SYMBOL_GPL(__tracepoint_##name); \ @@ -375,8 +389,6 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ static inline void trace_##name(proto) \ { } \ - static inline void trace_##name##_rcuidle(proto) \ - { } \ static inline int \ register_trace_##name(void (*probe)(data_proto), \ void *data) \ @@ -398,7 +410,10 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) return false; \ } +#define __DECLARE_TRACE_SYSCALL __DECLARE_TRACE + #define DEFINE_TRACE_FN(name, reg, unreg, proto, args) +#define DEFINE_TRACE_SYSCALL(name, reg, unreg, proto, args) #define DEFINE_TRACE(name, proto, args) #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) #define EXPORT_TRACEPOINT_SYMBOL(name) @@ -459,6 +474,11 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \ PARAMS(void *__data, proto)) +#define DECLARE_TRACE_SYSCALL(name, proto, args) \ + __DECLARE_TRACE_SYSCALL(name, PARAMS(proto), PARAMS(args), \ + cpu_online(raw_smp_processor_id()), \ + PARAMS(void *__data, proto)) + #define TRACE_EVENT_FLAGS(event, flag) #define TRACE_EVENT_PERF_PERM(event, expr...) @@ -596,6 +616,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) struct, assign, print) \ DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ PARAMS(args), PARAMS(cond)) +#define TRACE_EVENT_SYSCALL(name, proto, args, struct, assign, \ + print, reg, unreg) \ + DECLARE_TRACE_SYSCALL(name, PARAMS(proto), PARAMS(args)) #define TRACE_EVENT_FLAGS(event, flag) |