1 files changed, 203 insertions, 54 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5c9c6d907054..efe3202c0209 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -45,6 +45,12 @@ unsigned long __read_mostly	tracing_max_latency;
 unsigned long __read_mostly     tracing_thresh;
 
 /*
+ * On boot up, the ring buffer is set to the minimum size, so that
+ * we do not waste memory on systems that are not using tracing.
+ */
+static int ring_buffer_expanded;
+
+/*
  * We need to change this state when a selftest is running.
  * A selftest will lurk into the ring-buffer to count the
  * entries inserted during the selftest although some concurrent
@@ -128,6 +134,8 @@ static int __init set_ftrace(char *str)
 {
         strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
         default_bootup_tracer = bootup_tracer_buf;
+        /* We are using ftrace early, expand it */
+        ring_buffer_expanded = 1;
         return 1;
 }
 __setup("ftrace=", set_ftrace);
@@ -1171,10 +1179,10 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
 
 
 /**
- * trace_vprintk - write binary msg to tracing buffer
+ * trace_vbprintk - write binary msg to tracing buffer
  *
  */
-int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
+int trace_vbprintk(unsigned long ip, int depth, const char *fmt, va_list args)
 {
         static raw_spinlock_t trace_buf_lock =
                 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
@@ -1183,7 +1191,7 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
         struct ring_buffer_event *event;
         struct trace_array *tr = &global_trace;
         struct trace_array_cpu *data;
-        struct print_entry *entry;
+        struct bprint_entry *entry;
         unsigned long flags;
         int resched;
         int cpu, len = 0, size, pc;
@@ -1211,7 +1219,7 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
                 goto out_unlock;
 
         size = sizeof(*entry) + sizeof(u32) * len;
-        event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, flags, pc);
+        event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
         if (!event)
                 goto out_unlock;
         entry = ring_buffer_event_data(event);
@@ -1232,6 +1240,60 @@ out:
 
         return len;
 }
+EXPORT_SYMBOL_GPL(trace_vbprintk);
+
+int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
+{
+        static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
+        static char trace_buf[TRACE_BUF_SIZE];
+
+        struct ring_buffer_event *event;
+        struct trace_array *tr = &global_trace;
+        struct trace_array_cpu *data;
+        int cpu, len = 0, size, pc;
+        struct print_entry *entry;
+        unsigned long irq_flags;
+
+        if (tracing_disabled || tracing_selftest_running)
+                return 0;
+
+        pc = preempt_count();
+        preempt_disable_notrace();
+        cpu = raw_smp_processor_id();
+        data = tr->data[cpu];
+
+        if (unlikely(atomic_read(&data->disabled)))
+                goto out;
+
+        pause_graph_tracing();
+        raw_local_irq_save(irq_flags);
+        __raw_spin_lock(&trace_buf_lock);
+        len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+
+        len = min(len, TRACE_BUF_SIZE-1);
+        trace_buf[len] = 0;
+
+        size = sizeof(*entry) + len + 1;
+        event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
+        if (!event)
+                goto out_unlock;
+        entry = ring_buffer_event_data(event);
+        entry->ip                       = ip;
+        entry->depth                    = depth;
+
+        memcpy(&entry->buf, trace_buf, len);
+        entry->buf[len] = 0;
+        ring_buffer_unlock_commit(tr->buffer, event);
+
+ out_unlock:
+        __raw_spin_unlock(&trace_buf_lock);
+        raw_local_irq_restore(irq_flags);
+        unpause_graph_tracing();
+ out:
+        preempt_enable_notrace();
+
+        return len;
+}
 EXPORT_SYMBOL_GPL(trace_vprintk);
 
 enum trace_file_type {
@@ -1620,6 +1682,22 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
         return TRACE_TYPE_HANDLED;
 }
 
+static enum print_line_t 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;
+}
+
 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
 {
         struct trace_seq *s = &iter->seq;
@@ -1629,7 +1707,7 @@ static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
 
         trace_assign_type(field, entry);
 
-        ret = trace_seq_bprintf(s, field->fmt, field->buf);
+        ret = trace_seq_printf(s, "%s", field->buf);
         if (!ret)
                 return TRACE_TYPE_PARTIAL_LINE;
 
@@ -1658,6 +1736,19 @@ static int trace_empty(struct trace_iterator *iter)
 {
         int cpu;
 
+        /* If we are looking at one CPU buffer, only check that one */
+        if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
+                cpu = iter->cpu_file;
+                if (iter->buffer_iter[cpu]) {
+                        if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+                                return 0;
+                } else {
+                        if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
+                                return 0;
+                }
+                return 1;
+        }
+
         for_each_tracing_cpu(cpu) {
                 if (iter->buffer_iter[cpu]) {
                         if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
@@ -1681,6 +1772,11 @@ static enum print_line_t print_trace_line(struct trace_iterator *iter)
                         return ret;
         }
 
+        if (iter->ent->type == TRACE_BPRINT &&
+                        trace_flags & TRACE_ITER_PRINTK &&
+                        trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+                return print_bprintk_msg_only(iter);
+
         if (iter->ent->type == TRACE_PRINT &&
                         trace_flags & TRACE_ITER_PRINTK &&
                         trace_flags & TRACE_ITER_PRINTK_MSGONLY)
@@ -1784,17 +1880,11 @@ __tracing_open(struct inode *inode, struct file *file)
 
                         iter->buffer_iter[cpu] =
                                 ring_buffer_read_start(iter->tr->buffer, cpu);
-
-                        if (!iter->buffer_iter[cpu])
-                                goto fail_buffer;
                 }
         } else {
                 cpu = iter->cpu_file;
                 iter->buffer_iter[cpu] =
                                 ring_buffer_read_start(iter->tr->buffer, cpu);
-
-                if (!iter->buffer_iter[cpu])
-                        goto fail;
         }
 
         /* TODO stop tracer */
@@ -2315,6 +2405,75 @@ int tracer_init(struct tracer *t, struct trace_array *tr)
         return t->init(tr);
 }
 
+static int tracing_resize_ring_buffer(unsigned long size)
+{
+        int ret;
+
+        /*
+         * If kernel or user changes the size of the ring buffer
+         * we use the size that was given, and we can forget about
+         * expanding it later.
+         */
+        ring_buffer_expanded = 1;
+
+        ret = ring_buffer_resize(global_trace.buffer, size);
+        if (ret < 0)
+                return ret;
+
+        ret = ring_buffer_resize(max_tr.buffer, size);
+        if (ret < 0) {
+                int r;
+
+                r = ring_buffer_resize(global_trace.buffer,
+                                       global_trace.entries);
+                if (r < 0) {
+                        /*
+                         * AARGH! We are left with different
+                         * size max buffer!!!!
+                         * The max buffer is our "snapshot" buffer.
+                         * When a tracer needs a snapshot (one of the
+                         * latency tracers), it swaps the max buffer
+                         * with the saved snap shot. We succeeded to
+                         * update the size of the main buffer, but failed to
+                         * update the size of the max buffer. But when we tried
+                         * to reset the main buffer to the original size, we
+                         * failed there too. This is very unlikely to
+                         * happen, but if it does, warn and kill all
+                         * tracing.
+                         */
+                        WARN_ON(1);
+                        tracing_disabled = 1;
+                }
+                return ret;
+        }
+
+        global_trace.entries = size;
+
+        return ret;
+}
+
+/**
+ * tracing_update_buffers - used by tracing facility to expand ring buffers
+ *
+ * To save on memory when the tracing is never used on a system with it
+ * configured in. The ring buffers are set to a minimum size. But once
+ * a user starts to use the tracing facility, then they need to grow
+ * to their default size.
+ *
+ * This function is to be called when a tracer is about to be used.
+ */
+int tracing_update_buffers(void)
+{
+        int ret = 0;
+
+        mutex_lock(&trace_types_lock);
+        if (!ring_buffer_expanded)
+                ret = tracing_resize_ring_buffer(trace_buf_size);
+        mutex_unlock(&trace_types_lock);
+
+        return ret;
+}
+
 struct trace_option_dentry;
 
 static struct trace_option_dentry *
@@ -2331,6 +2490,14 @@ static int tracing_set_tracer(const char *buf)
         int ret = 0;
 
         mutex_lock(&trace_types_lock);
+
+        if (!ring_buffer_expanded) {
+                ret = tracing_resize_ring_buffer(trace_buf_size);
+                if (ret < 0)
+                        return ret;
+                ret = 0;
+        }
+
         for (t = trace_types; t; t = t->next) {
                 if (strcmp(t->name, buf) == 0)
                         break;
@@ -2856,10 +3023,18 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
                      size_t cnt, loff_t *ppos)
 {
         struct trace_array *tr = filp->private_data;
-        char buf[64];
+        char buf[96];
         int r;
 
-        r = sprintf(buf, "%lu\n", tr->entries >> 10);
+        mutex_lock(&trace_types_lock);
+        if (!ring_buffer_expanded)
+                r = sprintf(buf, "%lu (expanded: %lu)\n",
+                            tr->entries >> 10,
+                            trace_buf_size >> 10);
+        else
+                r = sprintf(buf, "%lu\n", tr->entries >> 10);
+        mutex_unlock(&trace_types_lock);
+
         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
@@ -2903,28 +3078,11 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
         val <<= 10;
 
         if (val != global_trace.entries) {
-                ret = ring_buffer_resize(global_trace.buffer, val);
+                ret = tracing_resize_ring_buffer(val);
                 if (ret < 0) {
                         cnt = ret;
                         goto out;
                 }
-
-                ret = ring_buffer_resize(max_tr.buffer, val);
-                if (ret < 0) {
-                        int r;
-                        cnt = ret;
-                        r = ring_buffer_resize(global_trace.buffer,
-                                               global_trace.entries);
-                        if (r < 0) {
-                                /* AARGH! We are left with different
-                                 * size max buffer!!!! */
-                                WARN_ON(1);
-                                tracing_disabled = 1;
-                        }
-                        goto out;
-                }
-
-                global_trace.entries = val;
         }
 
         filp->f_pos += cnt;
@@ -3385,6 +3543,11 @@ static void tracing_init_debugfs_percpu(long cpu)
                                 (void *) cpu, &tracing_fops);
         if (!entry)
                 pr_warning("Could not create debugfs 'trace' entry\n");
+
+        entry = debugfs_create_file("trace_pipe_raw", 0444, d_cpu,
+                                    (void *) cpu, &tracing_buffers_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
 }
 
 #ifdef CONFIG_FTRACE_SELFTEST
@@ -3668,7 +3831,6 @@ static __init void create_trace_options_dir(void)
 static __init int tracer_init_debugfs(void)
 {
         struct dentry *d_tracer;
-        struct dentry *buffers;
         struct dentry *entry;
         int cpu;
 
@@ -3741,26 +3903,6 @@ static __init int tracer_init_debugfs(void)
                 pr_warning("Could not create debugfs "
                            "'trace_marker' entry\n");
 
-        buffers = debugfs_create_dir("binary_buffers", d_tracer);
-
-        if (!buffers)
-                pr_warning("Could not create buffers directory\n");
-        else {
-                int cpu;
-                char buf[64];
-
-                for_each_tracing_cpu(cpu) {
-                        sprintf(buf, "%d", cpu);
-
-                        entry = debugfs_create_file(buf, 0444, buffers,
-                                                    (void *)(long)cpu,
-                                                    &tracing_buffers_fops);
-                        if (!entry)
-                                pr_warning("Could not create debugfs buffers "
-                                           "'%s' entry\n", buf);
-                }
-        }
-
 #ifdef CONFIG_DYNAMIC_FTRACE
         entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
                                     &ftrace_update_tot_cnt,
@@ -3916,6 +4058,7 @@ void ftrace_dump(void)
 __init static int tracer_alloc_buffers(void)
 {
         struct trace_array_cpu *data;
+        int ring_buf_size;
         int i;
         int ret = -ENOMEM;
 
@@ -3928,12 +4071,18 @@ __init static int tracer_alloc_buffers(void)
         if (!alloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL))
                 goto out_free_tracing_cpumask;
 
+        /* To save memory, keep the ring buffer size to its minimum */
+        if (ring_buffer_expanded)
+                ring_buf_size = trace_buf_size;
+        else
+                ring_buf_size = 1;
+
         cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
         cpumask_copy(tracing_cpumask, cpu_all_mask);
         cpumask_clear(tracing_reader_cpumask);
 
         /* TODO: make the number of buffers hot pluggable with CPUS */
-        global_trace.buffer = ring_buffer_alloc(trace_buf_size,
+        global_trace.buffer = ring_buffer_alloc(ring_buf_size,
                                                    TRACE_BUFFER_FLAGS);
         if (!global_trace.buffer) {
                 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
@@ -3944,7 +4093,7 @@ __init static int tracer_alloc_buffers(void)
 
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-        max_tr.buffer = ring_buffer_alloc(trace_buf_size,
+        max_tr.buffer = ring_buffer_alloc(ring_buf_size,
                                              TRACE_BUFFER_FLAGS);
         if (!max_tr.buffer) {
                 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");