[deliverable/linux.git] / kernel / trace / trace_output.c

/*
 * trace_output.c
 *
 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 */

#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>

#include "trace_output.h"

/* must be a power of 2 */
#define EVENT_HASHSIZE  128

DECLARE_RWSEM(trace_event_sem);

static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;

static int next_event_type = __TRACE_LAST_TYPE + 1;

#define EVENT_STORAGE_SIZE 128
static DEFINE_MUTEX(event_storage_mutex);
static char event_storage[EVENT_STORAGE_SIZE];

int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
        int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
        int ret;

        ret = seq_write(m, s->buffer, len);

        /*
         * Only reset this buffer if we successfully wrote to the
         * seq_file buffer.
         */
        if (!ret)
                trace_seq_init(s);

        return ret;
}

enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
{
        struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent;
        struct bputs_entry *field;
        int ret;

        trace_assign_type(field, entry);

        ret = trace_seq_puts(s, field->str);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
{
        struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent;
        struct bprint_entry *field;
        int ret;

        trace_assign_type(field, entry);

        ret = trace_seq_bprintf(s, field->fmt, field->buf);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
{
        struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent;
        struct print_entry *field;
        int ret;

        trace_assign_type(field, entry);

        ret = trace_seq_puts(s, field->buf);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

/**
 * trace_seq_printf - sequence printing of trace information
 * @s: trace sequence descriptor
 * @fmt: printf format string
 *
 * It returns 0 if the trace oversizes the buffer's free
 * space, 1 otherwise.
 *
 * The tracer may use either sequence operations or its own
 * copy to user routines. To simplify formating of a trace
 * trace_seq_printf is used to store strings into a special
 * buffer (@s). Then the output may be either used by
 * the sequencer or pulled into another buffer.
 */
int
trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
        int len = (PAGE_SIZE - 1) - s->len;
        va_list ap;
        int ret;

        if (s->full || !len)
                return 0;

        va_start(ap, fmt);
        ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
        va_end(ap);

        /* If we can't write it all, don't bother writing anything */
        if (ret >= len) {
                s->full = 1;
                return 0;
        }

        s->len += ret;

        return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);

/**
 * trace_seq_vprintf - sequence printing of trace information
 * @s: trace sequence descriptor
 * @fmt: printf format string
 *
 * The tracer may use either sequence operations or its own
 * copy to user routines. To simplify formating of a trace
 * trace_seq_printf is used to store strings into a special
 * buffer (@s). Then the output may be either used by
 * the sequencer or pulled into another buffer.
 */
int
trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
        int len = (PAGE_SIZE - 1) - s->len;
        int ret;

        if (s->full || !len)
                return 0;

        ret = vsnprintf(s->buffer + s->len, len, fmt, args);

        /* If we can't write it all, don't bother writing anything */
        if (ret >= len) {
                s->full = 1;
                return 0;
        }

        s->len += ret;

        return len;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);

int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
        int len = (PAGE_SIZE - 1) - s->len;
        int ret;

        if (s->full || !len)
                return 0;

        ret = bstr_printf(s->buffer + s->len, len, fmt, binary);

        /* If we can't write it all, don't bother writing anything */
        if (ret >= len) {
                s->full = 1;
                return 0;
        }

        s->len += ret;

        return len;
}

/**
 * trace_seq_puts - trace sequence printing of simple string
 * @s: trace sequence descriptor
 * @str: simple string to record
 *
 * The tracer may use either the sequence operations or its own
 * copy to user routines. This function records a simple string
 * into a special buffer (@s) for later retrieval by a sequencer
 * or other mechanism.
 */
int trace_seq_puts(struct trace_seq *s, const char *str)
{
        int len = strlen(str);

        if (s->full)
                return 0;

        if (len > ((PAGE_SIZE - 1) - s->len)) {
                s->full = 1;
                return 0;
        }

        memcpy(s->buffer + s->len, str, len);
        s->len += len;

        return len;
}

int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
        if (s->full)
                return 0;

        if (s->len >= (PAGE_SIZE - 1)) {
                s->full = 1;
                return 0;
        }

        s->buffer[s->len++] = c;

        return 1;
}
EXPORT_SYMBOL(trace_seq_putc);

int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
{
        if (s->full)
                return 0;

        if (len > ((PAGE_SIZE - 1) - s->len)) {
                s->full = 1;
                return 0;
        }

        memcpy(s->buffer + s->len, mem, len);
        s->len += len;

        return len;
}

int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
{
        unsigned char hex[HEX_CHARS];
        const unsigned char *data = mem;
        int i, j;

        if (s->full)
                return 0;

#ifdef __BIG_ENDIAN
        for (i = 0, j = 0; i < len; i++) {
#else
        for (i = len-1, j = 0; i >= 0; i--) {
#endif
                hex[j++] = hex_asc_hi(data[i]);
                hex[j++] = hex_asc_lo(data[i]);
        }
        hex[j++] = ' ';

        return trace_seq_putmem(s, hex, j);
}

void *trace_seq_reserve(struct trace_seq *s, size_t len)
{
        void *ret;

        if (s->full)
                return NULL;

        if (len > ((PAGE_SIZE - 1) - s->len)) {
                s->full = 1;
                return NULL;
        }

        ret = s->buffer + s->len;
        s->len += len;

        return ret;
}

int trace_seq_path(struct trace_seq *s, const struct path *path)
{
        unsigned char *p;

        if (s->full)
                return 0;

        if (s->len >= (PAGE_SIZE - 1)) {
                s->full = 1;
                return 0;
        }

        p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
        if (!IS_ERR(p)) {
                p = mangle_path(s->buffer + s->len, p, "\n");
                if (p) {
                        s->len = p - s->buffer;
                        return 1;
                }
        } else {
                s->buffer[s->len++] = '?';
                return 1;
        }

        s->full = 1;
        return 0;
}

const char *
ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
                       unsigned long flags,
                       const struct trace_print_flags *flag_array)
{
        unsigned long mask;
        const char *str;
        const char *ret = p->buffer + p->len;
        int i, first = 1;

        for (i = 0;  flag_array[i].name && flags; i++) {

                mask = flag_array[i].mask;
                if ((flags & mask) != mask)
                        continue;

                str = flag_array[i].name;
                flags &= ~mask;
                if (!first && delim)
                        trace_seq_puts(p, delim);
                else
                        first = 0;
                trace_seq_puts(p, str);
        }

        /* check for left over flags */
        if (flags) {
                if (!first && delim)
                        trace_seq_puts(p, delim);
                trace_seq_printf(p, "0x%lx", flags);
        }

        trace_seq_putc(p, 0);

        return ret;
}
EXPORT_SYMBOL(ftrace_print_flags_seq);

const char *
ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                         const struct trace_print_flags *symbol_array)
{
        int i;
        const char *ret = p->buffer + p->len;

        for (i = 0;  symbol_array[i].name; i++) {

                if (val != symbol_array[i].mask)
                        continue;

                trace_seq_puts(p, symbol_array[i].name);
                break;
        }

        if (ret == (const char *)(p->buffer + p->len))
                trace_seq_printf(p, "0x%lx", val);
                
        trace_seq_putc(p, 0);

        return ret;
}
EXPORT_SYMBOL(ftrace_print_symbols_seq);

#if BITS_PER_LONG == 32
const char *
ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
                         const struct trace_print_flags_u64 *symbol_array)
{
        int i;
        const char *ret = p->buffer + p->len;

        for (i = 0;  symbol_array[i].name; i++) {

                if (val != symbol_array[i].mask)
                        continue;

                trace_seq_puts(p, symbol_array[i].name);
                break;
        }

        if (ret == (const char *)(p->buffer + p->len))
                trace_seq_printf(p, "0x%llx", val);

        trace_seq_putc(p, 0);

        return ret;
}
EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
#endif

const char *
ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
{
        int i;
        const char *ret = p->buffer + p->len;

        for (i = 0; i < buf_len; i++)
                trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);

        trace_seq_putc(p, 0);

        return ret;
}
EXPORT_SYMBOL(ftrace_print_hex_seq);

int ftrace_raw_output_prep(struct trace_iterator *iter,
                           struct trace_event *trace_event)
{
        struct ftrace_event_call *event;
        struct trace_seq *s = &iter->seq;
        struct trace_seq *p = &iter->tmp_seq;
        struct trace_entry *entry;
        int ret;

        event = container_of(trace_event, struct ftrace_event_call, event);
        entry = iter->ent;

        if (entry->type != event->event.type) {
                WARN_ON_ONCE(1);
                return TRACE_TYPE_UNHANDLED;
        }

        trace_seq_init(p);
        ret = trace_seq_printf(s, "%s: ", event->name);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        return 0;
}
EXPORT_SYMBOL(ftrace_raw_output_prep);

static int ftrace_output_raw(struct trace_iterator *iter, char *name,
                             char *fmt, va_list ap)
{
        struct trace_seq *s = &iter->seq;
        int ret;

        ret = trace_seq_printf(s, "%s: ", name);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        ret = trace_seq_vprintf(s, fmt, ap);

        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
{
        va_list ap;
        int ret;

        va_start(ap, fmt);
        ret = ftrace_output_raw(iter, name, fmt, ap);
        va_end(ap);

        return ret;
}
EXPORT_SYMBOL_GPL(ftrace_output_call);

int ftrace_event_define_field(struct ftrace_event_call *call,
                              char *type, int len, char *item, int offset,
                              int field_size, int sign, int filter)
{
        int ret;

        mutex_lock(&event_storage_mutex);
        snprintf(event_storage, sizeof(event_storage),
                 "%s[%d]", type, len);
        ret = trace_define_field(call, event_storage, item, offset,
                                 field_size, sign, filter);
        mutex_unlock(&event_storage_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(ftrace_event_define_field);

#ifdef CONFIG_KRETPROBES
static inline const char *kretprobed(const char *name)
{
        static const char tramp_name[] = "kretprobe_trampoline";
        int size = sizeof(tramp_name);

        if (strncmp(tramp_name, name, size) == 0)
                return "[unknown/kretprobe'd]";
        return name;
}
#else
static inline const char *kretprobed(const char *name)
{
        return name;
}
#endif /* CONFIG_KRETPROBES */

static int
seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
{
#ifdef CONFIG_KALLSYMS
        char str[KSYM_SYMBOL_LEN];
        const char *name;

        kallsyms_lookup(address, NULL, NULL, NULL, str);

        name = kretprobed(str);

        return trace_seq_printf(s, fmt, name);
#endif
        return 1;
}

static int
seq_print_sym_offset(struct trace_seq *s, const char *fmt,
                     unsigned long address)
{
#ifdef CONFIG_KALLSYMS
        char str[KSYM_SYMBOL_LEN];
        const char *name;

        sprint_symbol(str, address);
        name = kretprobed(str);

        return trace_seq_printf(s, fmt, name);
#endif
        return 1;
}

#ifndef CONFIG_64BIT
# define IP_FMT "%08lx"
#else
# define IP_FMT "%016lx"
#endif

int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
                      unsigned long ip, unsigned long sym_flags)
{
        struct file *file = NULL;
        unsigned long vmstart = 0;
        int ret = 1;

        if (s->full)
                return 0;

        if (mm) {
                const struct vm_area_struct *vma;

                down_read(&mm->mmap_sem);
                vma = find_vma(mm, ip);
                if (vma) {
                        file = vma->vm_file;
                        vmstart = vma->vm_start;
                }
                if (file) {
                        ret = trace_seq_path(s, &file->f_path);
                        if (ret)
                                ret = trace_seq_printf(s, "[+0x%lx]",
                                                       ip - vmstart);
                }
                up_read(&mm->mmap_sem);
        }
        if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
                ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
        return ret;
}

int
seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
                      unsigned long sym_flags)
{
        struct mm_struct *mm = NULL;
        int ret = 1;
        unsigned int i;

        if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
                struct task_struct *task;
                /*
                 * we do the lookup on the thread group leader,
                 * since individual threads might have already quit!
                 */
                rcu_read_lock();
                task = find_task_by_vpid(entry->tgid);
                if (task)
                        mm = get_task_mm(task);
                rcu_read_unlock();
        }

        for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
                unsigned long ip = entry->caller[i];

                if (ip == ULONG_MAX || !ret)
                        break;
                if (ret)
                        ret = trace_seq_puts(s, " => ");
                if (!ip) {
                        if (ret)
                                ret = trace_seq_puts(s, "??");
                        if (ret)
                                ret = trace_seq_putc(s, '\n');
                        continue;
                }
                if (!ret)
                        break;
                if (ret)
                        ret = seq_print_user_ip(s, mm, ip, sym_flags);
                ret = trace_seq_putc(s, '\n');
        }

        if (mm)
                mmput(mm);
        return ret;
}

int
seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
{
        int ret;

        if (!ip)
                return trace_seq_putc(s, '0');

        if (sym_flags & TRACE_ITER_SYM_OFFSET)
                ret = seq_print_sym_offset(s, "%s", ip);
        else
                ret = seq_print_sym_short(s, "%s", ip);

        if (!ret)
                return 0;

        if (sym_flags & TRACE_ITER_SYM_ADDR)
                ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
        return ret;
}

/**
 * trace_print_lat_fmt - print the irq, preempt and lockdep fields
 * @s: trace seq struct to write to
 * @entry: The trace entry field from the ring buffer
 *
 * Prints the generic fields of irqs off, in hard or softirq, preempt
 * count.
 */
int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
{
        char hardsoft_irq;
        char need_resched;
        char irqs_off;
        int hardirq;
        int softirq;
        int ret;

        hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
        softirq = entry->flags & TRACE_FLAG_SOFTIRQ;

        irqs_off =
                (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
                (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
                '.';

        switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
                                TRACE_FLAG_PREEMPT_RESCHED)) {
        case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
                need_resched = 'N';
                break;
        case TRACE_FLAG_NEED_RESCHED:
                need_resched = 'n';
                break;
        case TRACE_FLAG_PREEMPT_RESCHED:
                need_resched = 'p';
                break;
        default:
                need_resched = '.';
                break;
        }

        hardsoft_irq =
                (hardirq && softirq) ? 'H' :
                hardirq ? 'h' :
                softirq ? 's' :
                '.';

        if (!trace_seq_printf(s, "%c%c%c",
                              irqs_off, need_resched, hardsoft_irq))
                return 0;

        if (entry->preempt_count)
                ret = trace_seq_printf(s, "%x", entry->preempt_count);
        else
                ret = trace_seq_putc(s, '.');

        return ret;
}

static int
lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
{
        char comm[TASK_COMM_LEN];

        trace_find_cmdline(entry->pid, comm);

        if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
                              comm, entry->pid, cpu))
                return 0;

        return trace_print_lat_fmt(s, entry);
}

static unsigned long preempt_mark_thresh_us = 100;

static int
lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
{
        unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
        unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
        unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
        unsigned long long rel_ts = next_ts - iter->ts;
        struct trace_seq *s = &iter->seq;

        if (in_ns) {
                abs_ts = ns2usecs(abs_ts);
                rel_ts = ns2usecs(rel_ts);
        }

        if (verbose && in_ns) {
                unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
                unsigned long abs_msec = (unsigned long)abs_ts;
                unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
                unsigned long rel_msec = (unsigned long)rel_ts;

                return trace_seq_printf(
                                s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
                                ns2usecs(iter->ts),
                                abs_msec, abs_usec,
                                rel_msec, rel_usec);
        } else if (verbose && !in_ns) {
                return trace_seq_printf(
                                s, "[%016llx] %lld (+%lld): ",
                                iter->ts, abs_ts, rel_ts);
        } else if (!verbose && in_ns) {
                return trace_seq_printf(
                                s, " %4lldus%c: ",
                                abs_ts,
                                rel_ts > preempt_mark_thresh_us ? '!' :
                                  rel_ts > 1 ? '+' : ' ');
        } else { /* !verbose && !in_ns */
                return trace_seq_printf(s, " %4lld: ", abs_ts);
        }
}

int trace_print_context(struct trace_iterator *iter)
{
        struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent;
        unsigned long long t;
        unsigned long secs, usec_rem;
        char comm[TASK_COMM_LEN];
        int ret;

        trace_find_cmdline(entry->pid, comm);

        ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
                               comm, entry->pid, iter->cpu);
        if (!ret)
                return 0;

        if (trace_flags & TRACE_ITER_IRQ_INFO) {
                ret = trace_print_lat_fmt(s, entry);
                if (!ret)
                        return 0;
        }

        if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
                t = ns2usecs(iter->ts);
                usec_rem = do_div(t, USEC_PER_SEC);
                secs = (unsigned long)t;
                return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
        } else
                return trace_seq_printf(s, " %12llu: ", iter->ts);
}

int trace_print_lat_context(struct trace_iterator *iter)
{
        u64 next_ts;
        int ret;
        /* trace_find_next_entry will reset ent_size */
        int ent_size = iter->ent_size;
        struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent,
                           *next_entry = trace_find_next_entry(iter, NULL,
                                                               &next_ts);
        unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);

        /* Restore the original ent_size */
        iter->ent_size = ent_size;

        if (!next_entry)
                next_ts = iter->ts;

        if (verbose) {
                char comm[TASK_COMM_LEN];

                trace_find_cmdline(entry->pid, comm);

                ret = trace_seq_printf(
                                s, "%16s %5d %3d %d %08x %08lx ",
                                comm, entry->pid, iter->cpu, entry->flags,
                                entry->preempt_count, iter->idx);
        } else {
                ret = lat_print_generic(s, entry, iter->cpu);
        }

        if (ret)
                ret = lat_print_timestamp(iter, next_ts);

        return ret;
}

static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;

static int task_state_char(unsigned long state)
{
        int bit = state ? __ffs(state) + 1 : 0;

        return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
}

/**
 * ftrace_find_event - find a registered event
 * @type: the type of event to look for
 *
 * Returns an event of type @type otherwise NULL
 * Called with trace_event_read_lock() held.
 */
struct trace_event *ftrace_find_event(int type)
{
        struct trace_event *event;
        unsigned key;

        key = type & (EVENT_HASHSIZE - 1);

        hlist_for_each_entry(event, &event_hash[key], node) {
                if (event->type == type)
                        return event;
        }

        return NULL;
}

static LIST_HEAD(ftrace_event_list);

static int trace_search_list(struct list_head **list)
{
        struct trace_event *e;
        int last = __TRACE_LAST_TYPE;

        if (list_empty(&ftrace_event_list)) {
                *list = &ftrace_event_list;
                return last + 1;
        }

        /*
         * We used up all possible max events,
         * lets see if somebody freed one.
         */
        list_for_each_entry(e, &ftrace_event_list, list) {
                if (e->type != last + 1)
                        break;
                last++;
        }

        /* Did we used up all 65 thousand events??? */
        if ((last + 1) > FTRACE_MAX_EVENT)
                return 0;

        *list = &e->list;
        return last + 1;
}

void trace_event_read_lock(void)
{
        down_read(&trace_event_sem);
}

void trace_event_read_unlock(void)
{
        up_read(&trace_event_sem);
}

/**
 * register_ftrace_event - register output for an event type
 * @event: the event type to register
 *
 * Event types are stored in a hash and this hash is used to
 * find a way to print an event. If the @event->type is set
 * then it will use that type, otherwise it will assign a
 * type to use.
 *
 * If you assign your own type, please make sure it is added
 * to the trace_type enum in trace.h, to avoid collisions
 * with the dynamic types.
 *
 * Returns the event type number or zero on error.
 */
int register_ftrace_event(struct trace_event *event)
{
        unsigned key;
        int ret = 0;

        down_write(&trace_event_sem);

        if (WARN_ON(!event))
                goto out;

        if (WARN_ON(!event->funcs))
                goto out;

        INIT_LIST_HEAD(&event->list);

        if (!event->type) {
                struct list_head *list = NULL;

                if (next_event_type > FTRACE_MAX_EVENT) {

                        event->type = trace_search_list(&list);
                        if (!event->type)
                                goto out;

                } else {
                        
                        event->type = next_event_type++;
                        list = &ftrace_event_list;
                }

                if (WARN_ON(ftrace_find_event(event->type)))
                        goto out;

                list_add_tail(&event->list, list);

        } else if (event->type > __TRACE_LAST_TYPE) {
                printk(KERN_WARNING "Need to add type to trace.h\n");
                WARN_ON(1);
                goto out;
        } else {
                /* Is this event already used */
                if (ftrace_find_event(event->type))
                        goto out;
        }

        if (event->funcs->trace == NULL)
                event->funcs->trace = trace_nop_print;
        if (event->funcs->raw == NULL)
                event->funcs->raw = trace_nop_print;
        if (event->funcs->hex == NULL)
                event->funcs->hex = trace_nop_print;
        if (event->funcs->binary == NULL)
                event->funcs->binary = trace_nop_print;

        key = event->type & (EVENT_HASHSIZE - 1);

        hlist_add_head(&event->node, &event_hash[key]);

        ret = event->type;
 out:
        up_write(&trace_event_sem);

        return ret;
}
EXPORT_SYMBOL_GPL(register_ftrace_event);

/*
 * Used by module code with the trace_event_sem held for write.
 */
int __unregister_ftrace_event(struct trace_event *event)
{
        hlist_del(&event->node);
        list_del(&event->list);
        return 0;
}

/**
 * unregister_ftrace_event - remove a no longer used event
 * @event: the event to remove
 */
int unregister_ftrace_event(struct trace_event *event)
{
        down_write(&trace_event_sem);
        __unregister_ftrace_event(event);
        up_write(&trace_event_sem);

        return 0;
}
EXPORT_SYMBOL_GPL(unregister_ftrace_event);

/*
 * Standard events
 */

enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
                                  struct trace_event *event)
{
        if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

/* TRACE_FN */
static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
                                        struct trace_event *event)
{
        struct ftrace_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        if (!seq_print_ip_sym(s, field->ip, flags))
                goto partial;

        if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
                if (!trace_seq_puts(s, " <-"))
                        goto partial;
                if (!seq_print_ip_sym(s,
                                      field->parent_ip,
                                      flags))
                        goto partial;
        }
        if (!trace_seq_putc(s, '\n'))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
                                      struct trace_event *event)
{
        struct ftrace_entry *field;

        trace_assign_type(field, iter->ent);

        if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
                              field->ip,
                              field->parent_ip))
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
                                      struct trace_event *event)
{
        struct ftrace_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        SEQ_PUT_HEX_FIELD_RET(s, field->ip);
        SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
                                      struct trace_event *event)
{
        struct ftrace_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        SEQ_PUT_FIELD_RET(s, field->ip);
        SEQ_PUT_FIELD_RET(s, field->parent_ip);

        return TRACE_TYPE_HANDLED;
}

static struct trace_event_functions trace_fn_funcs = {
        .trace          = trace_fn_trace,
        .raw            = trace_fn_raw,
        .hex            = trace_fn_hex,
        .binary         = trace_fn_bin,
};

static struct trace_event trace_fn_event = {
        .type           = TRACE_FN,
        .funcs          = &trace_fn_funcs,
};

/* TRACE_CTX an TRACE_WAKE */
static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
                                             char *delim)
{
        struct ctx_switch_entry *field;
        char comm[TASK_COMM_LEN];
        int S, T;


        trace_assign_type(field, iter->ent);

        T = task_state_char(field->next_state);
        S = task_state_char(field->prev_state);
        trace_find_cmdline(field->next_pid, comm);
        if (!trace_seq_printf(&iter->seq,
                              " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
                              field->prev_pid,
                              field->prev_prio,
                              S, delim,
                              field->next_cpu,
                              field->next_pid,
                              field->next_prio,
                              T, comm))
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
                                         struct trace_event *event)
{
        return trace_ctxwake_print(iter, "==>");
}

static enum print_line_t trace_wake_print(struct trace_iterator *iter,
                                          int flags, struct trace_event *event)
{
        return trace_ctxwake_print(iter, "  +");
}

static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
{
        struct ctx_switch_entry *field;
        int T;

        trace_assign_type(field, iter->ent);

        if (!S)
                S = task_state_char(field->prev_state);
        T = task_state_char(field->next_state);
        if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
                              field->prev_pid,
                              field->prev_prio,
                              S,
                              field->next_cpu,
                              field->next_pid,
                              field->next_prio,
                              T))
                return TRACE_TYPE_PARTIAL_LINE;

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
                                       struct trace_event *event)
{
        return trace_ctxwake_raw(iter, 0);
}

static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
                                        struct trace_event *event)
{
        return trace_ctxwake_raw(iter, '+');
}


static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
{
        struct ctx_switch_entry *field;
        struct trace_seq *s = &iter->seq;
        int T;

        trace_assign_type(field, iter->ent);

        if (!S)
                S = task_state_char(field->prev_state);
        T = task_state_char(field->next_state);

        SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
        SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
        SEQ_PUT_HEX_FIELD_RET(s, S);
        SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
        SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
        SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
        SEQ_PUT_HEX_FIELD_RET(s, T);

        return TRACE_TYPE_HANDLED;
}

static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
                                       struct trace_event *event)
{
        return trace_ctxwake_hex(iter, 0);
}

static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
                                        struct trace_event *event)
{
        return trace_ctxwake_hex(iter, '+');
}

static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
                                           int flags, struct trace_event *event)
{
        struct ctx_switch_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        SEQ_PUT_FIELD_RET(s, field->prev_pid);
        SEQ_PUT_FIELD_RET(s, field->prev_prio);
        SEQ_PUT_FIELD_RET(s, field->prev_state);
        SEQ_PUT_FIELD_RET(s, field->next_pid);
        SEQ_PUT_FIELD_RET(s, field->next_prio);
        SEQ_PUT_FIELD_RET(s, field->next_state);

        return TRACE_TYPE_HANDLED;
}

static struct trace_event_functions trace_ctx_funcs = {
        .trace          = trace_ctx_print,
        .raw            = trace_ctx_raw,
        .hex            = trace_ctx_hex,
        .binary         = trace_ctxwake_bin,
};

static struct trace_event trace_ctx_event = {
        .type           = TRACE_CTX,
        .funcs          = &trace_ctx_funcs,
};

static struct trace_event_functions trace_wake_funcs = {
        .trace          = trace_wake_print,
        .raw            = trace_wake_raw,
        .hex            = trace_wake_hex,
        .binary         = trace_ctxwake_bin,
};

static struct trace_event trace_wake_event = {
        .type           = TRACE_WAKE,
        .funcs          = &trace_wake_funcs,
};

/* TRACE_STACK */

static enum print_line_t trace_stack_print(struct trace_iterator *iter,
                                           int flags, struct trace_event *event)
{
        struct stack_entry *field;
        struct trace_seq *s = &iter->seq;
        unsigned long *p;
        unsigned long *end;

        trace_assign_type(field, iter->ent);
        end = (unsigned long *)((long)iter->ent + iter->ent_size);

        if (!trace_seq_puts(s, "<stack trace>\n"))
                goto partial;

        for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
                if (!trace_seq_puts(s, " => "))
                        goto partial;

                if (!seq_print_ip_sym(s, *p, flags))
                        goto partial;
                if (!trace_seq_putc(s, '\n'))
                        goto partial;
        }

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static struct trace_event_functions trace_stack_funcs = {
        .trace          = trace_stack_print,
};

static struct trace_event trace_stack_event = {
        .type           = TRACE_STACK,
        .funcs          = &trace_stack_funcs,
};

/* TRACE_USER_STACK */
static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
                                                int flags, struct trace_event *event)
{
        struct userstack_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        if (!trace_seq_puts(s, "<user stack trace>\n"))
                goto partial;

        if (!seq_print_userip_objs(field, s, flags))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static struct trace_event_functions trace_user_stack_funcs = {
        .trace          = trace_user_stack_print,
};

static struct trace_event trace_user_stack_event = {
        .type           = TRACE_USER_STACK,
        .funcs          = &trace_user_stack_funcs,
};

/* TRACE_BPUTS */
static enum print_line_t
trace_bputs_print(struct trace_iterator *iter, int flags,
                   struct trace_event *event)
{
        struct trace_entry *entry = iter->ent;
        struct trace_seq *s = &iter->seq;
        struct bputs_entry *field;

        trace_assign_type(field, entry);

        if (!seq_print_ip_sym(s, field->ip, flags))
                goto partial;

        if (!trace_seq_puts(s, ": "))
                goto partial;

        if (!trace_seq_puts(s, field->str))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}


static enum print_line_t
trace_bputs_raw(struct trace_iterator *iter, int flags,
                struct trace_event *event)
{
        struct bputs_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        if (!trace_seq_printf(s, ": %lx : ", field->ip))
                goto partial;

        if (!trace_seq_puts(s, field->str))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static struct trace_event_functions trace_bputs_funcs = {
        .trace          = trace_bputs_print,
        .raw            = trace_bputs_raw,
};

static struct trace_event trace_bputs_event = {
        .type           = TRACE_BPUTS,
        .funcs          = &trace_bputs_funcs,
};

/* TRACE_BPRINT */
static enum print_line_t
trace_bprint_print(struct trace_iterator *iter, int flags,
                   struct trace_event *event)
{
        struct trace_entry *entry = iter->ent;
        struct trace_seq *s = &iter->seq;
        struct bprint_entry *field;

        trace_assign_type(field, entry);

        if (!seq_print_ip_sym(s, field->ip, flags))
                goto partial;

        if (!trace_seq_puts(s, ": "))
                goto partial;

        if (!trace_seq_bprintf(s, field->fmt, field->buf))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}


static enum print_line_t
trace_bprint_raw(struct trace_iterator *iter, int flags,
                 struct trace_event *event)
{
        struct bprint_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        if (!trace_seq_printf(s, ": %lx : ", field->ip))
                goto partial;

        if (!trace_seq_bprintf(s, field->fmt, field->buf))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static struct trace_event_functions trace_bprint_funcs = {
        .trace          = trace_bprint_print,
        .raw            = trace_bprint_raw,
};

static struct trace_event trace_bprint_event = {
        .type           = TRACE_BPRINT,
        .funcs          = &trace_bprint_funcs,
};

/* TRACE_PRINT */
static enum print_line_t trace_print_print(struct trace_iterator *iter,
                                           int flags, struct trace_event *event)
{
        struct print_entry *field;
        struct trace_seq *s = &iter->seq;

        trace_assign_type(field, iter->ent);

        if (!seq_print_ip_sym(s, field->ip, flags))
                goto partial;

        if (!trace_seq_printf(s, ": %s", field->buf))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
                                         struct trace_event *event)
{
        struct print_entry *field;

        trace_assign_type(field, iter->ent);

        if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
                goto partial;

        return TRACE_TYPE_HANDLED;

 partial:
        return TRACE_TYPE_PARTIAL_LINE;
}

static struct trace_event_functions trace_print_funcs = {
        .trace          = trace_print_print,
        .raw            = trace_print_raw,
};

static struct trace_event trace_print_event = {
        .type           = TRACE_PRINT,
        .funcs          = &trace_print_funcs,
};


static struct trace_event *events[] __initdata = {
        &trace_fn_event,
        &trace_ctx_event,
        &trace_wake_event,
        &trace_stack_event,
        &trace_user_stack_event,
        &trace_bputs_event,
        &trace_bprint_event,
        &trace_print_event,
        NULL
};

__init static int init_events(void)
{
        struct trace_event *event;
        int i, ret;

        for (i = 0; events[i]; i++) {
                event = events[i];

                ret = register_ftrace_event(event);
                if (!ret) {
                        printk(KERN_WARNING "event %d failed to register\n",
                               event->type);
                        WARN_ON_ONCE(1);
                }
        }

        return 0;
}
early_initcall(init_events);