2009-04-09 01:40:59 +07:00
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#include <trace/syscall.h>
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2009-03-07 11:52:59 +07:00
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#include <linux/kernel.h>
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#include <asm/syscall.h>
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#include "trace_output.h"
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#include "trace.h"
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2009-03-16 04:10:37 +07:00
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/* Keep a counter of the syscall tracing users */
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static int refcount;
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/* Prevent from races on thread flags toggling */
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static DEFINE_MUTEX(syscall_trace_lock);
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2009-03-07 11:52:59 +07:00
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2009-03-16 04:10:36 +07:00
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/* Option to display the parameters types */
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2009-03-13 21:42:11 +07:00
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enum {
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TRACE_SYSCALLS_OPT_TYPES = 0x1,
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};
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static struct tracer_opt syscalls_opts[] = {
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{ TRACER_OPT(syscall_arg_type, TRACE_SYSCALLS_OPT_TYPES) },
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{ }
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};
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static struct tracer_flags syscalls_flags = {
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2009-03-16 04:10:36 +07:00
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.val = 0, /* By default: no parameters types */
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2009-03-13 21:42:11 +07:00
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.opts = syscalls_opts
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};
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enum print_line_t
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print_syscall_enter(struct trace_iterator *iter, int flags)
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{
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struct trace_seq *s = &iter->seq;
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struct trace_entry *ent = iter->ent;
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struct syscall_trace_enter *trace;
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struct syscall_metadata *entry;
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int i, ret, syscall;
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trace_assign_type(trace, ent);
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syscall = trace->nr;
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entry = syscall_nr_to_meta(syscall);
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if (!entry)
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goto end;
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ret = trace_seq_printf(s, "%s(", entry->name);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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for (i = 0; i < entry->nb_args; i++) {
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/* parameter types */
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if (syscalls_flags.val & TRACE_SYSCALLS_OPT_TYPES) {
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ret = trace_seq_printf(s, "%s ", entry->types[i]);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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}
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/* parameter values */
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ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i],
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trace->args[i],
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i == entry->nb_args - 1 ? ")" : ",");
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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}
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end:
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trace_seq_printf(s, "\n");
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return TRACE_TYPE_HANDLED;
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}
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enum print_line_t
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print_syscall_exit(struct trace_iterator *iter, int flags)
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{
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struct trace_seq *s = &iter->seq;
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struct trace_entry *ent = iter->ent;
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struct syscall_trace_exit *trace;
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int syscall;
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struct syscall_metadata *entry;
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int ret;
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trace_assign_type(trace, ent);
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syscall = trace->nr;
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entry = syscall_nr_to_meta(syscall);
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if (!entry) {
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trace_seq_printf(s, "\n");
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return TRACE_TYPE_HANDLED;
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}
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ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
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trace->ret);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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return TRACE_TYPE_HANDLED;
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}
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2009-03-07 11:52:59 +07:00
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void start_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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2009-03-16 04:10:37 +07:00
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mutex_lock(&syscall_trace_lock);
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2009-03-16 04:10:35 +07:00
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/* Don't enable the flag on the tasks twice */
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2009-03-16 04:10:37 +07:00
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if (++refcount != 1)
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goto unlock;
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2009-03-07 11:52:59 +07:00
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2009-03-13 21:42:11 +07:00
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arch_init_ftrace_syscalls();
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2009-03-07 11:52:59 +07:00
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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2009-03-16 04:10:37 +07:00
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unlock:
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mutex_unlock(&syscall_trace_lock);
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2009-03-07 11:52:59 +07:00
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}
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void stop_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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2009-03-16 04:10:37 +07:00
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mutex_lock(&syscall_trace_lock);
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2009-03-16 04:10:35 +07:00
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/* There are perhaps still some users */
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2009-03-16 04:10:37 +07:00
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if (--refcount)
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goto unlock;
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2009-03-07 11:52:59 +07:00
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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2009-03-16 04:10:37 +07:00
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unlock:
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mutex_unlock(&syscall_trace_lock);
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2009-03-07 11:52:59 +07:00
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}
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void ftrace_syscall_enter(struct pt_regs *regs)
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{
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2009-03-13 21:42:11 +07:00
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struct syscall_trace_enter *entry;
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struct syscall_metadata *sys_data;
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struct ring_buffer_event *event;
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int size;
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2009-03-07 11:52:59 +07:00
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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2009-03-13 21:42:11 +07:00
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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return;
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size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
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event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_ENTER, size,
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0, 0);
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if (!event)
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return;
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entry = ring_buffer_event_data(event);
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entry->nr = syscall_nr;
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syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
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trace_current_buffer_unlock_commit(event, 0, 0);
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trace_wake_up();
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2009-03-07 11:52:59 +07:00
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}
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void ftrace_syscall_exit(struct pt_regs *regs)
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{
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2009-03-13 21:42:11 +07:00
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struct syscall_trace_exit *entry;
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struct syscall_metadata *sys_data;
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struct ring_buffer_event *event;
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2009-03-07 11:52:59 +07:00
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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2009-03-13 21:42:11 +07:00
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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return;
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event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_EXIT,
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sizeof(*entry), 0, 0);
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if (!event)
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return;
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entry = ring_buffer_event_data(event);
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entry->nr = syscall_nr;
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entry->ret = syscall_get_return_value(current, regs);
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trace_current_buffer_unlock_commit(event, 0, 0);
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trace_wake_up();
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2009-03-07 11:52:59 +07:00
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}
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static int init_syscall_tracer(struct trace_array *tr)
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{
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start_ftrace_syscalls();
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return 0;
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}
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static void reset_syscall_tracer(struct trace_array *tr)
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{
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stop_ftrace_syscalls();
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2009-03-16 04:10:35 +07:00
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tracing_reset_online_cpus(tr);
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2009-03-07 11:52:59 +07:00
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}
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static struct trace_event syscall_enter_event = {
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2009-03-13 21:42:11 +07:00
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.type = TRACE_SYSCALL_ENTER,
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.trace = print_syscall_enter,
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2009-03-07 11:52:59 +07:00
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};
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static struct trace_event syscall_exit_event = {
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2009-03-13 21:42:11 +07:00
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.type = TRACE_SYSCALL_EXIT,
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.trace = print_syscall_exit,
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2009-03-07 11:52:59 +07:00
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};
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static struct tracer syscall_tracer __read_mostly = {
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2009-03-13 21:42:11 +07:00
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.name = "syscall",
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2009-03-07 11:52:59 +07:00
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.init = init_syscall_tracer,
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2009-03-13 21:42:11 +07:00
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.reset = reset_syscall_tracer,
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.flags = &syscalls_flags,
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2009-03-07 11:52:59 +07:00
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};
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__init int register_ftrace_syscalls(void)
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{
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int ret;
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ret = register_ftrace_event(&syscall_enter_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_enter_event.type);
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WARN_ON_ONCE(1);
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}
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ret = register_ftrace_event(&syscall_exit_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_exit_event.type);
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WARN_ON_ONCE(1);
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}
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return register_tracer(&syscall_tracer);
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}
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device_initcall(register_ftrace_syscalls);
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