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Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c274
1 files changed, 267 insertions, 7 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ea055aa21cd..12539f72f4a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -11,31 +11,30 @@
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 William Lee Irwin III
*/
+#include <linux/ring_buffer.h>
#include <linux/utsrelease.h>
+#include <linux/stacktrace.h>
+#include <linux/writeback.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
+#include <linux/irqflags.h>
#include <linux/debugfs.h>
#include <linux/pagemap.h>
#include <linux/hardirq.h>
#include <linux/linkage.h>
#include <linux/uaccess.h>
+#include <linux/kprobes.h>
#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/percpu.h>
+#include <linux/splice.h>
#include <linux/kdebug.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/gfp.h>
#include <linux/fs.h>
-#include <linux/kprobes.h>
-#include <linux/writeback.h>
-#include <linux/splice.h>
-
-#include <linux/stacktrace.h>
-#include <linux/ring_buffer.h>
-#include <linux/irqflags.h>
#include "trace.h"
#include "trace_output.h"
@@ -3005,6 +3004,246 @@ static struct file_operations tracing_mark_fops = {
.write = tracing_mark_write,
};
+struct ftrace_buffer_info {
+ struct trace_array *tr;
+ void *spare;
+ int cpu;
+ unsigned int read;
+};
+
+static int tracing_buffers_open(struct inode *inode, struct file *filp)
+{
+ int cpu = (int)(long)inode->i_private;
+ struct ftrace_buffer_info *info;
+
+ if (tracing_disabled)
+ return -ENODEV;
+
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->tr = &global_trace;
+ info->cpu = cpu;
+ info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
+ /* Force reading ring buffer for first read */
+ info->read = (unsigned int)-1;
+ if (!info->spare)
+ goto out;
+
+ filp->private_data = info;
+
+ return 0;
+
+ out:
+ kfree(info);
+ return -ENOMEM;
+}
+
+static ssize_t
+tracing_buffers_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ struct ftrace_buffer_info *info = filp->private_data;
+ unsigned int pos;
+ ssize_t ret;
+ size_t size;
+
+ /* Do we have previous read data to read? */
+ if (info->read < PAGE_SIZE)
+ goto read;
+
+ info->read = 0;
+
+ ret = ring_buffer_read_page(info->tr->buffer,
+ &info->spare,
+ count,
+ info->cpu, 0);
+ if (ret < 0)
+ return 0;
+
+ pos = ring_buffer_page_len(info->spare);
+
+ if (pos < PAGE_SIZE)
+ memset(info->spare + pos, 0, PAGE_SIZE - pos);
+
+read:
+ size = PAGE_SIZE - info->read;
+ if (size > count)
+ size = count;
+
+ ret = copy_to_user(ubuf, info->spare + info->read, size);
+ if (ret)
+ return -EFAULT;
+ *ppos += size;
+ info->read += size;
+
+ return size;
+}
+
+static int tracing_buffers_release(struct inode *inode, struct file *file)
+{
+ struct ftrace_buffer_info *info = file->private_data;
+
+ ring_buffer_free_read_page(info->tr->buffer, info->spare);
+ kfree(info);
+
+ return 0;
+}
+
+struct buffer_ref {
+ struct ring_buffer *buffer;
+ void *page;
+ int ref;
+};
+
+static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+ if (--ref->ref)
+ return;
+
+ ring_buffer_free_read_page(ref->buffer, ref->page);
+ kfree(ref);
+ buf->private = 0;
+}
+
+static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ return 1;
+}
+
+static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+ ref->ref++;
+}
+
+/* Pipe buffer operations for a buffer. */
+static struct pipe_buf_operations buffer_pipe_buf_ops = {
+ .can_merge = 0,
+ .map = generic_pipe_buf_map,
+ .unmap = generic_pipe_buf_unmap,
+ .confirm = generic_pipe_buf_confirm,
+ .release = buffer_pipe_buf_release,
+ .steal = buffer_pipe_buf_steal,
+ .get = buffer_pipe_buf_get,
+};
+
+/*
+ * Callback from splice_to_pipe(), if we need to release some pages
+ * at the end of the spd in case we error'ed out in filling the pipe.
+ */
+static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+ struct buffer_ref *ref =
+ (struct buffer_ref *)spd->partial[i].private;
+
+ if (--ref->ref)
+ return;
+
+ ring_buffer_free_read_page(ref->buffer, ref->page);
+ kfree(ref);
+ spd->partial[i].private = 0;
+}
+
+static ssize_t
+tracing_buffers_splice_read(struct file *file, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
+{
+ struct ftrace_buffer_info *info = file->private_data;
+ struct partial_page partial[PIPE_BUFFERS];
+ struct page *pages[PIPE_BUFFERS];
+ struct splice_pipe_desc spd = {
+ .pages = pages,
+ .partial = partial,
+ .flags = flags,
+ .ops = &buffer_pipe_buf_ops,
+ .spd_release = buffer_spd_release,
+ };
+ struct buffer_ref *ref;
+ int size, i;
+ size_t ret;
+
+ /*
+ * We can't seek on a buffer input
+ */
+ if (unlikely(*ppos))
+ return -ESPIPE;
+
+
+ for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
+ struct page *page;
+ int r;
+
+ ref = kzalloc(sizeof(*ref), GFP_KERNEL);
+ if (!ref)
+ break;
+
+ ref->buffer = info->tr->buffer;
+ ref->page = ring_buffer_alloc_read_page(ref->buffer);
+ if (!ref->page) {
+ kfree(ref);
+ break;
+ }
+
+ r = ring_buffer_read_page(ref->buffer, &ref->page,
+ len, info->cpu, 0);
+ if (r < 0) {
+ ring_buffer_free_read_page(ref->buffer,
+ ref->page);
+ kfree(ref);
+ break;
+ }
+
+ /*
+ * zero out any left over data, this is going to
+ * user land.
+ */
+ size = ring_buffer_page_len(ref->page);
+ if (size < PAGE_SIZE)
+ memset(ref->page + size, 0, PAGE_SIZE - size);
+
+ page = virt_to_page(ref->page);
+
+ spd.pages[i] = page;
+ spd.partial[i].len = PAGE_SIZE;
+ spd.partial[i].offset = 0;
+ spd.partial[i].private = (unsigned long)ref;
+ spd.nr_pages++;
+ }
+
+ spd.nr_pages = i;
+
+ /* did we read anything? */
+ if (!spd.nr_pages) {
+ if (flags & SPLICE_F_NONBLOCK)
+ ret = -EAGAIN;
+ else
+ ret = 0;
+ /* TODO: block */
+ return ret;
+ }
+
+ ret = splice_to_pipe(pipe, &spd);
+
+ return ret;
+}
+
+static const struct file_operations tracing_buffers_fops = {
+ .open = tracing_buffers_open,
+ .read = tracing_buffers_read,
+ .release = tracing_buffers_release,
+ .splice_read = tracing_buffers_splice_read,
+ .llseek = no_llseek,
+};
+
#ifdef CONFIG_DYNAMIC_FTRACE
int __weak ftrace_arch_read_dyn_info(char *buf, int size)
@@ -3399,6 +3638,7 @@ 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;
@@ -3471,6 +3711,26 @@ 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,