tracing: Ftrace dynamic ftrace_event_call support
[pandora-kernel.git] / kernel / trace / trace_syscalls.c
index 5e57964..5931933 100644 (file)
@@ -1,30 +1,18 @@
 #include <trace/syscall.h>
+#include <trace/events/syscalls.h>
 #include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/perf_counter.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);
-
-/* Option to display the parameters types */
-enum {
-       TRACE_SYSCALLS_OPT_TYPES = 0x1,
-};
-
-static struct tracer_opt syscalls_opts[] = {
-       { TRACER_OPT(syscall_arg_type, TRACE_SYSCALLS_OPT_TYPES) },
-       { }
-};
-
-static struct tracer_flags syscalls_flags = {
-       .val = 0, /* By default: no parameters types */
-       .opts = syscalls_opts
-};
+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);
 
 enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags)
@@ -35,35 +23,46 @@ print_syscall_enter(struct trace_iterator *iter, int flags)
        struct syscall_metadata *entry;
        int i, ret, syscall;
 
-       trace_assign_type(trace, ent);
-
+       trace = (typeof(trace))ent;
        syscall = trace->nr;
-
        entry = syscall_nr_to_meta(syscall);
+
        if (!entry)
                goto end;
 
+       if (entry->enter_id != ent->type) {
+               WARN_ON_ONCE(1);
+               goto end;
+       }
+
        ret = trace_seq_printf(s, "%s(", entry->name);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
        for (i = 0; i < entry->nb_args; i++) {
                /* parameter types */
-               if (syscalls_flags.val & TRACE_SYSCALLS_OPT_TYPES) {
+               if (trace_flags & TRACE_ITER_VERBOSE) {
                        ret = trace_seq_printf(s, "%s ", entry->types[i]);
                        if (!ret)
                                return TRACE_TYPE_PARTIAL_LINE;
                }
                /* parameter values */
-               ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i],
+               ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
                                       trace->args[i],
-                                      i == entry->nb_args - 1 ? ")" : ",");
+                                      i == entry->nb_args - 1 ? "" : ", ");
                if (!ret)
                        return TRACE_TYPE_PARTIAL_LINE;
        }
 
+       ret = trace_seq_putc(s, ')');
+       if (!ret)
+               return TRACE_TYPE_PARTIAL_LINE;
+
 end:
-       trace_seq_printf(s, "\n");
+       ret =  trace_seq_putc(s, '\n');
+       if (!ret)
+               return TRACE_TYPE_PARTIAL_LINE;
+
        return TRACE_TYPE_HANDLED;
 }
 
@@ -77,16 +76,20 @@ print_syscall_exit(struct trace_iterator *iter, int flags)
        struct syscall_metadata *entry;
        int ret;
 
-       trace_assign_type(trace, ent);
-
+       trace = (typeof(trace))ent;
        syscall = trace->nr;
-
        entry = syscall_nr_to_meta(syscall);
+
        if (!entry) {
                trace_seq_printf(s, "\n");
                return TRACE_TYPE_HANDLED;
        }
 
+       if (entry->exit_id != ent->type) {
+               WARN_ON_ONCE(1);
+               return TRACE_TYPE_UNHANDLED;
+       }
+
        ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
                                trace->ret);
        if (!ret)
@@ -95,54 +98,127 @@ print_syscall_exit(struct trace_iterator *iter, int flags)
        return TRACE_TYPE_HANDLED;
 }
 
-void start_ftrace_syscalls(void)
+extern char *__bad_type_size(void);
+
+#define SYSCALL_FIELD(type, name)                                      \
+       sizeof(type) != sizeof(trace.name) ?                            \
+               __bad_type_size() :                                     \
+               #type, #name, offsetof(typeof(trace), name), sizeof(trace.name)
+
+int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
 {
-       unsigned long flags;
-       struct task_struct *g, *t;
+       int i;
+       int nr;
+       int ret;
+       struct syscall_metadata *entry;
+       struct syscall_trace_enter trace;
+       int offset = offsetof(struct syscall_trace_enter, args);
 
-       mutex_lock(&syscall_trace_lock);
+       nr = syscall_name_to_nr(call->data);
+       entry = syscall_nr_to_meta(nr);
 
-       /* Don't enable the flag on the tasks twice */
-       if (++refcount != 1)
-               goto unlock;
+       if (!entry)
+               return 0;
+
+       ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n",
+                              SYSCALL_FIELD(int, nr));
+       if (!ret)
+               return 0;
 
-       arch_init_ftrace_syscalls();
-       read_lock_irqsave(&tasklist_lock, flags);
+       for (i = 0; i < entry->nb_args; i++) {
+               ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i],
+                                       entry->args[i]);
+               if (!ret)
+                       return 0;
+               ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;\n", offset,
+                                      sizeof(unsigned long));
+               if (!ret)
+                       return 0;
+               offset += sizeof(unsigned long);
+       }
 
-       do_each_thread(g, t) {
-               set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
-       } while_each_thread(g, t);
+       trace_seq_puts(s, "\nprint fmt: \"");
+       for (i = 0; i < entry->nb_args; i++) {
+               ret = trace_seq_printf(s, "%s: 0x%%0%zulx%s", entry->args[i],
+                                       sizeof(unsigned long),
+                                       i == entry->nb_args - 1 ? "" : ", ");
+               if (!ret)
+                       return 0;
+       }
+       trace_seq_putc(s, '"');
 
-       read_unlock_irqrestore(&tasklist_lock, flags);
+       for (i = 0; i < entry->nb_args; i++) {
+               ret = trace_seq_printf(s, ", ((unsigned long)(REC->%s))",
+                                      entry->args[i]);
+               if (!ret)
+                       return 0;
+       }
 
-unlock:
-       mutex_unlock(&syscall_trace_lock);
+       return trace_seq_putc(s, '\n');
 }
 
-void stop_ftrace_syscalls(void)
+int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
 {
-       unsigned long flags;
-       struct task_struct *g, *t;
+       int ret;
+       struct syscall_trace_exit trace;
 
-       mutex_lock(&syscall_trace_lock);
+       ret = trace_seq_printf(s,
+                              "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
+                              "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n",
+                              SYSCALL_FIELD(int, nr),
+                              SYSCALL_FIELD(unsigned long, ret));
+       if (!ret)
+               return 0;
 
-       /* There are perhaps still some users */
-       if (--refcount)
-               goto unlock;
+       return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n");
+}
 
-       read_lock_irqsave(&tasklist_lock, flags);
+int syscall_enter_define_fields(struct ftrace_event_call *call)
+{
+       struct syscall_trace_enter trace;
+       struct syscall_metadata *meta;
+       int ret;
+       int nr;
+       int i;
+       int offset = offsetof(typeof(trace), args);
+
+       nr = syscall_name_to_nr(call->data);
+       meta = syscall_nr_to_meta(nr);
+
+       if (!meta)
+               return 0;
+
+       ret = trace_define_common_fields(call);
+       if (ret)
+               return ret;
+
+       for (i = 0; i < meta->nb_args; i++) {
+               ret = trace_define_field(call, (char *)meta->types[i],
+                                        (char *)meta->args[i], offset,
+                                        sizeof(unsigned long), 0,
+                                        FILTER_OTHER);
+               offset += sizeof(unsigned long);
+       }
 
-       do_each_thread(g, t) {
-               clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
-       } while_each_thread(g, t);
+       return ret;
+}
 
-       read_unlock_irqrestore(&tasklist_lock, flags);
+int syscall_exit_define_fields(struct ftrace_event_call *call)
+{
+       struct syscall_trace_exit trace;
+       int ret;
 
-unlock:
-       mutex_unlock(&syscall_trace_lock);
+       ret = trace_define_common_fields(call);
+       if (ret)
+               return ret;
+
+       ret = trace_define_field(call, SYSCALL_FIELD(unsigned long, ret), 0,
+                                FILTER_OTHER);
+
+       return ret;
 }
 
-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;
@@ -151,6 +227,8 @@ 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)
@@ -158,7 +236,7 @@ void ftrace_syscall_enter(struct pt_regs *regs)
 
        size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
 
-       event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_ENTER, size,
+       event = trace_current_buffer_lock_reserve(sys_data->enter_id, size,
                                                        0, 0);
        if (!event)
                return;
@@ -167,11 +245,11 @@ void ftrace_syscall_enter(struct pt_regs *regs)
        entry->nr = syscall_nr;
        syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
 
-       trace_current_buffer_unlock_commit(event, 0, 0);
-       trace_wake_up();
+       if (!filter_current_check_discard(sys_data->enter_event, entry, event))
+               trace_current_buffer_unlock_commit(event, 0, 0);
 }
 
-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;
@@ -179,12 +257,14 @@ 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)
                return;
 
-       event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_EXIT,
+       event = trace_current_buffer_lock_reserve(sys_data->exit_id,
                                sizeof(*entry), 0, 0);
        if (!event)
                return;
@@ -193,58 +273,243 @@ void ftrace_syscall_exit(struct pt_regs *regs)
        entry->nr = syscall_nr;
        entry->ret = syscall_get_return_value(current, regs);
 
-       trace_current_buffer_unlock_commit(event, 0, 0);
-       trace_wake_up();
+       if (!filter_current_check_discard(sys_data->exit_event, entry, event))
+               trace_current_buffer_unlock_commit(event, 0, 0);
 }
 
-static int init_syscall_tracer(struct trace_array *tr)
+int reg_event_syscall_enter(struct ftrace_event_call *call)
 {
-       start_ftrace_syscalls();
+       int ret = 0;
+       int num;
+       char *name;
+
+       name = (char *)call->data;
+       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_sys_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;
+}
+
+void unreg_event_syscall_enter(struct ftrace_event_call *call)
+{
+       int num;
+       char *name;
 
-       return 0;
+       name = (char *)call->data;
+       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_sys_enter(ftrace_syscall_enter);
+       mutex_unlock(&syscall_trace_lock);
 }
 
-static void reset_syscall_tracer(struct trace_array *tr)
+int reg_event_syscall_exit(struct ftrace_event_call *call)
 {
-       stop_ftrace_syscalls();
-       tracing_reset_online_cpus(tr);
+       int ret = 0;
+       int num;
+       char *name;
+
+       name = (char *)call->data;
+       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_sys_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;
 }
 
-static struct trace_event syscall_enter_event = {
-       .type           = TRACE_SYSCALL_ENTER,
-       .trace          = print_syscall_enter,
-};
+void unreg_event_syscall_exit(struct ftrace_event_call *call)
+{
+       int num;
+       char *name;
+
+       name = (char *)call->data;
+       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_sys_exit(ftrace_syscall_exit);
+       mutex_unlock(&syscall_trace_lock);
+}
 
-static struct trace_event syscall_exit_event = {
-       .type           = TRACE_SYSCALL_EXIT,
-       .trace          = print_syscall_exit,
+struct trace_event event_syscall_enter = {
+       .trace                  = print_syscall_enter,
 };
 
-static struct tracer syscall_tracer __read_mostly = {
-       .name           = "syscall",
-       .init           = init_syscall_tracer,
-       .reset          = reset_syscall_tracer,
-       .flags          = &syscalls_flags,
+struct trace_event event_syscall_exit = {
+       .trace                  = print_syscall_exit,
 };
 
-__init int register_ftrace_syscalls(void)
+#ifdef CONFIG_EVENT_PROFILE
+
+static DECLARE_BITMAP(enabled_prof_enter_syscalls, FTRACE_SYSCALL_MAX);
+static DECLARE_BITMAP(enabled_prof_exit_syscalls, FTRACE_SYSCALL_MAX);
+static int sys_prof_refcount_enter;
+static int sys_prof_refcount_exit;
+
+static void prof_syscall_enter(struct pt_regs *regs, long id)
 {
-       int ret;
+       struct syscall_trace_enter *rec;
+       struct syscall_metadata *sys_data;
+       int syscall_nr;
+       int size;
 
-       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);
+       syscall_nr = syscall_get_nr(current, regs);
+       if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
+               return;
+
+       sys_data = syscall_nr_to_meta(syscall_nr);
+       if (!sys_data)
+               return;
+
+       /* get the size after alignment with the u32 buffer size field */
+       size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
+       size = ALIGN(size + sizeof(u32), sizeof(u64));
+       size -= sizeof(u32);
+
+       do {
+               char raw_data[size];
+
+               /* zero the dead bytes from align to not leak stack to user */
+               *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+
+               rec = (struct syscall_trace_enter *) raw_data;
+               tracing_generic_entry_update(&rec->ent, 0, 0);
+               rec->ent.type = sys_data->enter_id;
+               rec->nr = syscall_nr;
+               syscall_get_arguments(current, regs, 0, sys_data->nb_args,
+                                      (unsigned long *)&rec->args);
+               perf_tpcounter_event(sys_data->enter_id, 0, 1, rec, size);
+       } while(0);
+}
+
+int reg_prof_syscall_enter(char *name)
+{
+       int ret = 0;
+       int num;
+
+       num = syscall_name_to_nr(name);
+       if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+               return -ENOSYS;
+
+       mutex_lock(&syscall_trace_lock);
+       if (!sys_prof_refcount_enter)
+               ret = register_trace_sys_enter(prof_syscall_enter);
+       if (ret) {
+               pr_info("event trace: Could not activate"
+                               "syscall entry trace point");
+       } else {
+               set_bit(num, enabled_prof_enter_syscalls);
+               sys_prof_refcount_enter++;
        }
+       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_prof_syscall_enter(char *name)
+{
+       int num;
+
+       num = syscall_name_to_nr(name);
+       if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+               return;
+
+       mutex_lock(&syscall_trace_lock);
+       sys_prof_refcount_enter--;
+       clear_bit(num, enabled_prof_enter_syscalls);
+       if (!sys_prof_refcount_enter)
+               unregister_trace_sys_enter(prof_syscall_enter);
+       mutex_unlock(&syscall_trace_lock);
+}
+
+static void prof_syscall_exit(struct pt_regs *regs, long ret)
+{
+       struct syscall_metadata *sys_data;
+       struct syscall_trace_exit rec;
+       int syscall_nr;
+
+       syscall_nr = syscall_get_nr(current, regs);
+       if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
+               return;
+
+       sys_data = syscall_nr_to_meta(syscall_nr);
+       if (!sys_data)
+               return;
+
+       tracing_generic_entry_update(&rec.ent, 0, 0);
+       rec.ent.type = sys_data->exit_id;
+       rec.nr = syscall_nr;
+       rec.ret = syscall_get_return_value(current, regs);
+
+       perf_tpcounter_event(sys_data->exit_id, 0, 1, &rec, sizeof(rec));
+}
+
+int reg_prof_syscall_exit(char *name)
+{
+       int ret = 0;
+       int num;
+
+       num = syscall_name_to_nr(name);
+       if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+               return -ENOSYS;
+
+       mutex_lock(&syscall_trace_lock);
+       if (!sys_prof_refcount_exit)
+               ret = register_trace_sys_exit(prof_syscall_exit);
+       if (ret) {
+               pr_info("event trace: Could not activate"
+                               "syscall entry trace point");
+       } else {
+               set_bit(num, enabled_prof_exit_syscalls);
+               sys_prof_refcount_exit++;
        }
+       mutex_unlock(&syscall_trace_lock);
+       return ret;
+}
 
-       return register_tracer(&syscall_tracer);
+void unreg_prof_syscall_exit(char *name)
+{
+       int num;
+
+       num = syscall_name_to_nr(name);
+       if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+               return;
+
+       mutex_lock(&syscall_trace_lock);
+       sys_prof_refcount_exit--;
+       clear_bit(num, enabled_prof_exit_syscalls);
+       if (!sys_prof_refcount_exit)
+               unregister_trace_sys_exit(prof_syscall_exit);
+       mutex_unlock(&syscall_trace_lock);
 }
-device_initcall(register_ftrace_syscalls);
+
+#endif
+
+