diff options
| -rw-r--r-- | include/linux/syscalls.h | 61 | ||||
| -rw-r--r-- | include/trace/syscall.h | 18 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 183 |
3 files changed, 159 insertions, 103 deletions
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 80de7003d8c..5e5b4d33a31 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -64,6 +64,7 @@ struct perf_counter_attr; #include <linux/sem.h> #include <asm/siginfo.h> #include <asm/signal.h> +#include <linux/unistd.h> #include <linux/quota.h> #include <linux/key.h> #include <trace/syscall.h> @@ -112,6 +113,59 @@ struct perf_counter_attr; #define __SC_STR_TDECL5(t, a, ...) #t, __SC_STR_TDECL4(__VA_ARGS__) #define __SC_STR_TDECL6(t, a, ...) #t, __SC_STR_TDECL5(__VA_ARGS__) + +#define SYSCALL_TRACE_ENTER_EVENT(sname) \ + static struct ftrace_event_call event_enter_##sname; \ + static int init_enter_##sname(void) \ + { \ + int num; \ + num = syscall_name_to_nr("sys"#sname); \ + if (num < 0) \ + return -ENOSYS; \ + register_ftrace_event(&event_syscall_enter); \ + INIT_LIST_HEAD(&event_enter_##sname.fields); \ + init_preds(&event_enter_##sname); \ + return 0; \ + } \ + static struct ftrace_event_call __used \ + __attribute__((__aligned__(4))) \ + __attribute__((section("_ftrace_events"))) \ + event_enter_##sname = { \ + .name = "sys_enter"#sname, \ + .system = "syscalls", \ + .event = &event_syscall_enter, \ + .raw_init = init_enter_##sname, \ + .regfunc = reg_event_syscall_enter, \ + .unregfunc = unreg_event_syscall_enter, \ + .data = "sys"#sname, \ + } + +#define SYSCALL_TRACE_EXIT_EVENT(sname) \ + static struct ftrace_event_call event_exit_##sname; \ + static int init_exit_##sname(void) \ + { \ + int num; \ + num = syscall_name_to_nr("sys"#sname); \ + if (num < 0) \ + return -ENOSYS; \ + register_ftrace_event(&event_syscall_exit); \ + INIT_LIST_HEAD(&event_exit_##sname.fields); \ + init_preds(&event_exit_##sname); \ + return 0; \ + } \ + static struct ftrace_event_call __used \ + __attribute__((__aligned__(4))) \ + __attribute__((section("_ftrace_events"))) \ + event_exit_##sname = { \ + .name = "sys_exit"#sname, \ + .system = "syscalls", \ + .event = &event_syscall_exit, \ + .raw_init = init_exit_##sname, \ + .regfunc = reg_event_syscall_exit, \ + .unregfunc = unreg_event_syscall_exit, \ + .data = "sys"#sname, \ + } + #define SYSCALL_METADATA(sname, nb) \ static const struct syscall_metadata __used \ __attribute__((__aligned__(4))) \ @@ -121,7 +175,9 @@ struct perf_counter_attr; .nb_args = nb, \ .types = types_##sname, \ .args = args_##sname, \ - } + }; \ + SYSCALL_TRACE_ENTER_EVENT(sname); \ + SYSCALL_TRACE_EXIT_EVENT(sname); #define SYSCALL_DEFINE0(sname) \ static const struct syscall_metadata __used \ @@ -131,8 +187,9 @@ struct perf_counter_attr; .name = "sys_"#sname, \ .nb_args = 0, \ }; \ + SYSCALL_TRACE_ENTER_EVENT(_##sname); \ + SYSCALL_TRACE_EXIT_EVENT(_##sname); \ asmlinkage long sys_##sname(void) - #else #define SYSCALL_DEFINE0(name) asmlinkage long sys_##name(void) #endif diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 3951d774de1..73fb8b4a995 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -2,6 +2,8 @@ #define _TRACE_SYSCALL_H #include <linux/tracepoint.h> +#include <linux/unistd.h> +#include <linux/ftrace_event.h> #include <asm/ptrace.h> @@ -40,15 +42,13 @@ struct syscall_metadata { #ifdef CONFIG_FTRACE_SYSCALLS extern struct syscall_metadata *syscall_nr_to_meta(int nr); -extern void start_ftrace_syscalls(void); -extern void stop_ftrace_syscalls(void); -extern void ftrace_syscall_enter(struct pt_regs *regs); -extern void ftrace_syscall_exit(struct pt_regs *regs); -#else -static inline void start_ftrace_syscalls(void) { } -static inline void stop_ftrace_syscalls(void) { } -static inline void ftrace_syscall_enter(struct pt_regs *regs) { } -static inline void ftrace_syscall_exit(struct pt_regs *regs) { } +extern int syscall_name_to_nr(char *name); +extern struct trace_event event_syscall_enter; +extern struct trace_event event_syscall_exit; +extern int reg_event_syscall_enter(void *ptr); +extern void unreg_event_syscall_enter(void *ptr); +extern int reg_event_syscall_exit(void *ptr); +extern void unreg_event_syscall_exit(void *ptr); #endif #endif /* _TRACE_SYSCALL_H */ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 08aed439fea..c7ae25ee95d 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -1,15 +1,16 @@ #include <trace/syscall.h> #include <linux/kernel.h> +#include <linux/ftrace.h> #include <asm/syscall.h> #include "trace_output.h" #include "trace.h" -/* Keep a counter of the syscall tracing users */ -static int refcount; - -/* Prevent from races on thread flags toggling */ static DEFINE_MUTEX(syscall_trace_lock); +static int sys_refcount_enter; +static int sys_refcount_exit; +static DECLARE_BITMAP(enabled_enter_syscalls, FTRACE_SYSCALL_MAX); +static DECLARE_BITMAP(enabled_exit_syscalls, FTRACE_SYSCALL_MAX); /* Option to display the parameters types */ enum { @@ -95,53 +96,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags) return TRACE_TYPE_HANDLED; } -void start_ftrace_syscalls(void) -{ - unsigned long flags; - struct task_struct *g, *t; - - mutex_lock(&syscall_trace_lock); - - /* Don't enable the flag on the tasks twice */ - if (++refcount != 1) - goto unlock; - - read_lock_irqsave(&tasklist_lock, flags); - - do_each_thread(g, t) { - set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE); - } while_each_thread(g, t); - - read_unlock_irqrestore(&tasklist_lock, flags); - -unlock: - mutex_unlock(&syscall_trace_lock); -} - -void stop_ftrace_syscalls(void) -{ - unsigned long flags; - struct task_struct *g, *t; - - mutex_lock(&syscall_trace_lock); - - /* There are perhaps still some users */ - if (--refcount) - goto unlock; - - read_lock_irqsave(&tasklist_lock, flags); - - do_each_thread(g, t) { - clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE); - } while_each_thread(g, t); - - read_unlock_irqrestore(&tasklist_lock, flags); - -unlock: - mutex_unlock(&syscall_trace_lock); -} - -void ftrace_syscall_enter(struct pt_regs *regs) +void ftrace_syscall_enter(struct pt_regs *regs, long id) { struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; @@ -150,6 +105,8 @@ void ftrace_syscall_enter(struct pt_regs *regs) int syscall_nr; syscall_nr = syscall_get_nr(current, regs); + if (!test_bit(syscall_nr, enabled_enter_syscalls)) + return; sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -170,7 +127,7 @@ void ftrace_syscall_enter(struct pt_regs *regs) trace_wake_up(); } -void ftrace_syscall_exit(struct pt_regs *regs) +void ftrace_syscall_exit(struct pt_regs *regs, long ret) { struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; @@ -178,6 +135,8 @@ void ftrace_syscall_exit(struct pt_regs *regs) int syscall_nr; syscall_nr = syscall_get_nr(current, regs); + if (!test_bit(syscall_nr, enabled_exit_syscalls)) + return; sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -196,54 +155,94 @@ void ftrace_syscall_exit(struct pt_regs *regs) trace_wake_up(); } -static int init_syscall_tracer(struct trace_array *tr) +int reg_event_syscall_enter(void *ptr) { - start_ftrace_syscalls(); - - return 0; + int ret = 0; + int num; + char *name; + + name = (char *)ptr; + num = syscall_name_to_nr(name); + if (num < 0 || num >= FTRACE_SYSCALL_MAX) + return -ENOSYS; + mutex_lock(&syscall_trace_lock); + if (!sys_refcount_enter) + ret = register_trace_syscall_enter(ftrace_syscall_enter); + if (ret) { + pr_info("event trace: Could not activate" + "syscall entry trace point"); + } else { + set_bit(num, enabled_enter_syscalls); + sys_refcount_enter++; + } + mutex_unlock(&syscall_trace_lock); + return ret; } -static void reset_syscall_tracer(struct trace_array *tr) +void unreg_event_syscall_enter(void *ptr) { - stop_ftrace_syscalls(); - tracing_reset_online_cpus(tr); -} - -static struct trace_event syscall_enter_event = { - .type = TRACE_SYSCALL_ENTER, - .trace = print_syscall_enter, -}; - -static struct trace_event syscall_exit_event = { - .type = TRACE_SYSCALL_EXIT, - .trace = print_syscall_exit, -}; + int num; + char *name; -static struct tracer syscall_tracer __read_mostly = { - .name = "syscall", - .init = init_syscall_tracer, - .reset = reset_syscall_tracer, - .flags = &syscalls_flags, -}; + name = (char *)ptr; + num = syscall_name_to_nr(name); + if (num < 0 || num >= FTRACE_SYSCALL_MAX) + return; + mutex_lock(&syscall_trace_lock); + sys_refcount_enter--; + clear_bit(num, enabled_enter_syscalls); + if (!sys_refcount_enter) + unregister_trace_syscall_enter(ftrace_syscall_enter); + mutex_unlock(&syscall_trace_lock); +} -__init int register_ftrace_syscalls(void) +int reg_event_syscall_exit(void *ptr) { - int ret; - - ret = register_ftrace_event(&syscall_enter_event); - if (!ret) { - printk(KERN_WARNING "event %d failed to register\n", - syscall_enter_event.type); - WARN_ON_ONCE(1); + int ret = 0; + int num; + char *name; + + name = (char *)ptr; + num = syscall_name_to_nr(name); + if (num < 0 || num >= FTRACE_SYSCALL_MAX) + return -ENOSYS; + mutex_lock(&syscall_trace_lock); + if (!sys_refcount_exit) + ret = register_trace_syscall_exit(ftrace_syscall_exit); + if (ret) { + pr_info("event trace: Could not activate" + "syscall exit trace point"); + } else { + set_bit(num, enabled_exit_syscalls); + sys_refcount_exit++; } + mutex_unlock(&syscall_trace_lock); + return ret; +} - ret = register_ftrace_event(&syscall_exit_event); - if (!ret) { - printk(KERN_WARNING "event %d failed to register\n", - syscall_exit_event.type); - WARN_ON_ONCE(1); - } +void unreg_event_syscall_exit(void *ptr) +{ + int num; + char *name; - return register_tracer(&syscall_tracer); + name = (char *)ptr; + num = syscall_name_to_nr(name); + if (num < 0 || num >= FTRACE_SYSCALL_MAX) + return; + mutex_lock(&syscall_trace_lock); + sys_refcount_exit--; + clear_bit(num, enabled_exit_syscalls); + if (!sys_refcount_exit) + unregister_trace_syscall_exit(ftrace_syscall_exit); + mutex_unlock(&syscall_trace_lock); } -device_initcall(register_ftrace_syscalls); + +struct trace_event event_syscall_enter = { + .trace = print_syscall_enter, + .type = TRACE_SYSCALL_ENTER +}; + +struct trace_event event_syscall_exit = { + .trace = print_syscall_exit, + .type = TRACE_SYSCALL_EXIT +}; 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