diff options
| -rw-r--r-- | include/linux/ftrace.h | 21 | ||||
| -rw-r--r-- | kernel/trace/Kconfig | 10 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 113 |
5 files changed, 147 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e1583f2639b..c146c1021a2 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -503,4 +503,25 @@ static inline void trace_hw_branch_oops(void) {} #endif /* CONFIG_HW_BRANCH_TRACER */ +/* + * A syscall entry in the ftrace syscalls array. + * + * @syscall_nr: syscall number + */ +struct syscall_trace_entry { + int syscall_nr; +}; + +#ifdef CONFIG_FTRACE_SYSCALLS +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) { } +#endif + #endif /* _LINUX_FTRACE_H */ diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 8e4a2a61cd7..95a0ad191f1 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -34,6 +34,9 @@ config HAVE_FTRACE_MCOUNT_RECORD config HAVE_HW_BRANCH_TRACER bool +config HAVE_FTRACE_SYSCALLS + bool + config TRACER_MAX_TRACE bool @@ -175,6 +178,13 @@ config EVENT_TRACER allowing the user to pick and choose which trace point they want to trace. +config FTRACE_SYSCALLS + bool "Trace syscalls" + depends on HAVE_FTRACE_SYSCALLS + select TRACING + help + Basic tracer to catch the syscall entry and exit events. + config BOOT_TRACER bool "Trace boot initcalls" select TRACING diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index c7a2943796e..c3feea01c3e 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -43,5 +43,6 @@ obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o obj-$(CONFIG_EVENT_TRACER) += trace_events.o obj-$(CONFIG_EVENT_TRACER) += events.o obj-$(CONFIG_EVENT_TRACER) += trace_export.o +obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index c5e1d8865fe..3d49daae47d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -30,6 +30,8 @@ enum trace_type { TRACE_GRAPH_ENT, TRACE_USER_STACK, TRACE_HW_BRANCHES, + TRACE_SYSCALL_ENTER, + TRACE_SYSCALL_EXIT, TRACE_KMEM_ALLOC, TRACE_KMEM_FREE, TRACE_POWER, diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c new file mode 100644 index 00000000000..66cf97449af --- /dev/null +++ b/kernel/trace/trace_syscalls.c @@ -0,0 +1,113 @@ +#include <linux/ftrace.h> +#include <linux/kernel.h> + +#include <asm/syscall.h> + +#include "trace_output.h" +#include "trace.h" + +static atomic_t refcount; + +void start_ftrace_syscalls(void) +{ + unsigned long flags; + struct task_struct *g, *t; + + if (atomic_inc_return(&refcount) != 1) + goto out; + + 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); +out: + atomic_dec(&refcount); +} + +void stop_ftrace_syscalls(void) +{ + unsigned long flags; + struct task_struct *g, *t; + + if (atomic_dec_return(&refcount)) + goto out; + + 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); +out: + atomic_inc(&refcount); +} + +void ftrace_syscall_enter(struct pt_regs *regs) +{ + int syscall_nr; + + syscall_nr = syscall_get_nr(current, regs); + + trace_printk("syscall %d enter\n", syscall_nr); +} + +void ftrace_syscall_exit(struct pt_regs *regs) +{ + int syscall_nr; + + syscall_nr = syscall_get_nr(current, regs); + + trace_printk("syscall %d exit\n", syscall_nr); +} + +static int init_syscall_tracer(struct trace_array *tr) +{ + start_ftrace_syscalls(); + + return 0; +} + +static void reset_syscall_tracer(struct trace_array *tr) +{ + stop_ftrace_syscalls(); +} + +static struct trace_event syscall_enter_event = { + .type = TRACE_SYSCALL_ENTER, +}; + +static struct trace_event syscall_exit_event = { + .type = TRACE_SYSCALL_EXIT, +}; + +static struct tracer syscall_tracer __read_mostly = { + .name = "syscall", + .init = init_syscall_tracer, + .reset = reset_syscall_tracer +}; + +__init int register_ftrace_syscalls(void) +{ + 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); + } + + 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); + } + + return register_tracer(&syscall_tracer); +} +device_initcall(register_ftrace_syscalls); |