7 files changed, 178 insertions, 6 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ac78910d7416..f8e8b34dc427 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -124,7 +124,10 @@
 #define FTRACE_EVENTS() . = ALIGN(8);                                   \
                         VMLINUX_SYMBOL(__start_ftrace_events) = .;      \
                         *(_ftrace_events)                               \
-                        VMLINUX_SYMBOL(__stop_ftrace_events) = .;
+                        VMLINUX_SYMBOL(__stop_ftrace_events) = .;       \
+                        VMLINUX_SYMBOL(__start_ftrace_enum_maps) = .;   \
+                        *(_ftrace_enum_map)                             \
+                        VMLINUX_SYMBOL(__stop_ftrace_enum_maps) = .;
 #else
 #define FTRACE_EVENTS()
 #endif
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 62b8fac7ded5..112cf49d9576 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -285,7 +285,7 @@ struct ftrace_event_call {
                 struct tracepoint       *tp;
         };
         struct trace_event      event;
-        const char              *print_fmt;
+        char                    *print_fmt;
         struct event_filter     *filter;
         void                    *mod;
         void                    *data;
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c72851328ca9..a5f7f3ecafa3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -36,6 +36,12 @@ struct tracepoint {
         struct tracepoint_func __rcu *funcs;
 };
 
+struct trace_enum_map {
+        const char              *system;
+        const char              *enum_string;
+        unsigned long           enum_value;
+};
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -87,6 +93,8 @@ extern void syscall_unregfunc(void);
 
 #define PARAMS(args...) args
 
+#define TRACE_DEFINE_ENUM(x)
+
 #endif /* _LINUX_TRACEPOINT_H */
 
 /*
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 2f9b95b6d3fb..37d4b10b111d 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -33,6 +33,19 @@
 
 TRACE_MAKE_SYSTEM_STR();
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)                            \
+        static struct trace_enum_map __used __initdata  \
+        __##TRACE_SYSTEM##_##a =                        \
+        {                                               \
+                .system = TRACE_SYSTEM_STRING,          \
+                .enum_string = #a,                      \
+                .enum_value = a                         \
+        };                                              \
+        static struct trace_enum_map __used             \
+        __attribute__((section("_ftrace_enum_map")))    \
+        *TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
+
 /*
  * DECLARE_EVENT_CLASS can be used to add a generic function
  * handlers for events. That is, if all events have the same
@@ -136,6 +149,9 @@ TRACE_MAKE_SYSTEM_STR();
  * The size of an array is also encoded, in the higher 16 bits of <item>.
  */
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)
+
 #undef __field
 #define __field(type, item)
 
@@ -553,7 +569,7 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *      .trace                  = ftrace_raw_output_<call>, <-- stage 2
  * };
  *
- * static const char print_fmt_<call>[] = <TP_printk>;
+ * static char print_fmt_<call>[] = <TP_printk>;
  *
  * static struct ftrace_event_class __used event_class_<template> = {
  *      .system                 = "<system>",
@@ -704,7 +720,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)  \
 _TRACE_PERF_PROTO(call, PARAMS(proto));                                 \
-static const char print_fmt_##call[] = print;                           \
+static char print_fmt_##call[] = print;                                 \
 static struct ftrace_event_class __used __refdata event_class_##call = { \
         .system                 = TRACE_SYSTEM_STRING,                  \
         .define_fields          = ftrace_define_fields_##call,          \
@@ -733,7 +749,7 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 #undef DEFINE_EVENT_PRINT
 #define DEFINE_EVENT_PRINT(template, call, proto, args, print)          \
                                                                         \
-static const char print_fmt_##call[] = print;                           \
+static char print_fmt_##call[] = print;                                 \
                                                                         \
 static struct ftrace_event_call __used event_##call = {                 \
         .class                  = &event_class_##template,              \
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 62c6506d663f..ebf49649534c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3908,6 +3908,20 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
         .write          = tracing_saved_cmdlines_size_write,
 };
 
+static void
+trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+{
+        struct trace_enum_map **map;
+        int len = stop - start;
+
+        if (len <= 0)
+                return;
+
+        map = start;
+
+        trace_event_enum_update(map, len);
+}
+
 static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
                        size_t cnt, loff_t *ppos)
@@ -6542,6 +6556,14 @@ struct dentry *tracing_init_dentry(void)
         return tr->dir;
 }
 
+extern struct trace_enum_map *__start_ftrace_enum_maps[];
+extern struct trace_enum_map *__stop_ftrace_enum_maps[];
+
+static void __init trace_enum_init(void)
+{
+        trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+}
+
 static __init int tracer_init_debugfs(void)
 {
         struct dentry *d_tracer;
@@ -6566,6 +6588,8 @@ static __init int tracer_init_debugfs(void)
         trace_create_file("saved_cmdlines_size", 0644, d_tracer,
                           NULL, &tracing_saved_cmdlines_size_fops);
 
+        trace_enum_init();
+
 #ifdef CONFIG_DYNAMIC_FTRACE
         trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
                         &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
@@ -6888,7 +6912,7 @@ void __init trace_init(void)
                         tracepoint_printk = 0;
         }
         tracer_alloc_buffers();
-        trace_event_init();     
+        trace_event_init();
 }
 
 __init static int clear_boot_tracer(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dd8205a35760..b48d4b08f691 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1309,8 +1309,10 @@ static inline void init_ftrace_syscalls(void) { }
 
 #ifdef CONFIG_EVENT_TRACING
 void trace_event_init(void);
+void trace_event_enum_update(struct trace_enum_map **map, int len);
 #else
 static inline void __init trace_event_init(void) { }
+static inlin void trace_event_enum_update(struct trace_enum_map **map, int len) { }
 #endif
 
 extern struct trace_iterator *tracepoint_print_iter;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index db54dda10ccc..fc58c50fbf01 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1704,6 +1704,125 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
         return 0;
 }
 
+static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
+{
+        int rlen;
+        int elen;
+
+        /* Find the length of the enum value as a string */
+        elen = snprintf(ptr, 0, "%ld", map->enum_value);
+        /* Make sure there's enough room to replace the string with the value */
+        if (len < elen)
+                return NULL;
+
+        snprintf(ptr, elen + 1, "%ld", map->enum_value);
+
+        /* Get the rest of the string of ptr */
+        rlen = strlen(ptr + len);
+        memmove(ptr + elen, ptr + len, rlen);
+        /* Make sure we end the new string */
+        ptr[elen + rlen] = 0;
+
+        return ptr + elen;
+}
+
+static void update_event_printk(struct ftrace_event_call *call,
+                                struct trace_enum_map *map)
+{
+        char *ptr;
+        int quote = 0;
+        int len = strlen(map->enum_string);
+
+        for (ptr = call->print_fmt; *ptr; ptr++) {
+                if (*ptr == '\\') {
+                        ptr++;
+                        /* paranoid */
+                        if (!*ptr)
+                                break;
+                        continue;
+                }
+                if (*ptr == '"') {
+                        quote ^= 1;
+                        continue;
+                }
+                if (quote)
+                        continue;
+                if (isdigit(*ptr)) {
+                        /* skip numbers */
+                        do {
+                                ptr++;
+                                /* Check for alpha chars like ULL */
+                        } while (isalnum(*ptr));
+                        /*
+                         * A number must have some kind of delimiter after
+                         * it, and we can ignore that too.
+                         */
+                        continue;
+                }
+                if (isalpha(*ptr) || *ptr == '_') {
+                        if (strncmp(map->enum_string, ptr, len) == 0 &&
+                            !isalnum(ptr[len]) && ptr[len] != '_') {
+                                ptr = enum_replace(ptr, map, len);
+                                /* Hmm, enum string smaller than value */
+                                if (WARN_ON_ONCE(!ptr))
+                                        return;
+                                /*
+                                 * No need to decrement here, as enum_replace()
+                                 * returns the pointer to the character passed
+                                 * the enum, and two enums can not be placed
+                                 * back to back without something in between.
+                                 * We can skip that something in between.
+                                 */
+                                continue;
+                        }
+                skip_more:
+                        do {
+                                ptr++;
+                        } while (isalnum(*ptr) || *ptr == '_');
+                        /*
+                         * If what comes after this variable is a '.' or
+                         * '->' then we can continue to ignore that string.
+                         */
+                        if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
+                                ptr += *ptr == '.' ? 1 : 2;
+                                goto skip_more;
+                        }
+                        /*
+                         * Once again, we can skip the delimiter that came
+                         * after the string.
+                         */
+                        continue;
+                }
+        }
+}
+
+void trace_event_enum_update(struct trace_enum_map **map, int len)
+{
+        struct ftrace_event_call *call, *p;
+        const char *last_system = NULL;
+        int last_i;
+        int i;
+
+        down_write(&trace_event_sem);
+        list_for_each_entry_safe(call, p, &ftrace_events, list) {
+                /* events are usually grouped together with systems */
+                if (!last_system || call->class->system != last_system) {
+                        last_i = 0;
+                        last_system = call->class->system;
+                }
+
+                for (i = last_i; i < len; i++) {
+                        if (call->class->system == map[i]->system) {
+                                /* Save the first system if need be */
+                                if (!last_i)
+                                        last_i = i;
+                                update_event_printk(call, map[i]);
+                        }
+                }
+        }
+        up_write(&trace_event_sem);
+}
+
 static struct ftrace_event_file *
 trace_create_new_event(struct ftrace_event_call *call,
                        struct trace_array *tr)