1 files changed, 365 insertions, 0 deletions

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
new file mode 100644
index 000000000000..1f3f80002b5e
--- /dev/null
+++ b/kernel/trace/trace_output.c
@@ -0,0 +1,365 @@
+/*
+ * 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
+
+static DEFINE_MUTEX(trace_event_mutex);
+static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+
+static int next_event_type = __TRACE_LAST_TYPE + 1;
+
+/**
+ * trace_seq_printf - 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_printf(struct trace_seq *s, const char *fmt, ...)
+{
+        int len = (PAGE_SIZE - 1) - s->len;
+        va_list ap;
+        int ret;
+
+        if (!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)
+                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 (len > ((PAGE_SIZE - 1) - s->len))
+                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->len >= (PAGE_SIZE - 1))
+                return 0;
+
+        s->buffer[s->len++] = c;
+
+        return 1;
+}
+
+int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
+{
+        if (len > ((PAGE_SIZE - 1) - s->len))
+                return 0;
+
+        memcpy(s->buffer + s->len, mem, len);
+        s->len += len;
+
+        return len;
+}
+
+int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
+{
+        unsigned char hex[HEX_CHARS];
+        unsigned char *data = mem;
+        int i, j;
+
+#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);
+}
+
+int trace_seq_path(struct trace_seq *s, struct path *path)
+{
+        unsigned char *p;
+
+        if (s->len >= (PAGE_SIZE - 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;
+        }
+
+        return 0;
+}
+
+#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 (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->ent.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 (i && ret)
+                        ret = trace_seq_puts(s, " <- ");
+                if (!ip) {
+                        if (ret)
+                                ret = trace_seq_puts(s, "??");
+                        continue;
+                }
+                if (!ret)
+                        break;
+                if (ret)
+                        ret = seq_print_user_ip(s, mm, ip, sym_flags);
+        }
+
+        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_printf(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;
+}
+
+/**
+ * ftrace_find_event - find a registered event
+ * @type: the type of event to look for
+ *
+ * Returns an event of type @type otherwise NULL
+ */
+struct trace_event *ftrace_find_event(int type)
+{
+        struct trace_event *event;
+        struct hlist_node *n;
+        unsigned key;
+
+        key = type & (EVENT_HASHSIZE - 1);
+
+        hlist_for_each_entry_rcu(event, n, &event_hash[key], node) {
+                if (event->type == type)
+                        return event;
+        }
+
+        return NULL;
+}
+
+/**
+ * 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;
+
+        mutex_lock(&trace_event_mutex);
+
+        if (!event->type)
+                event->type = next_event_type++;
+        else if (event->type > __TRACE_LAST_TYPE) {
+                printk(KERN_WARNING "Need to add type to trace.h\n");
+                WARN_ON(1);
+        }
+
+        if (ftrace_find_event(event->type))
+                goto out;
+
+        key = event->type & (EVENT_HASHSIZE - 1);
+
+        hlist_add_head_rcu(&event->node, &event_hash[key]);
+
+        ret = event->type;
+ out:
+        mutex_unlock(&trace_event_mutex);
+
+        return ret;
+}
+
+/**
+ * unregister_ftrace_event - remove a no longer used event
+ * @event: the event to remove
+ */
+int unregister_ftrace_event(struct trace_event *event)
+{
+        mutex_lock(&trace_event_mutex);
+        hlist_del(&event->node);
+        mutex_unlock(&trace_event_mutex);
+
+        return 0;
+}