tracing: Add new trace_marker_raw
A new file is created: /sys/kernel/debug/tracing/trace_marker_raw This allows for appications to create data structures and write the binary data directly into it, and then read the trace data out from trace_pipe_raw into the same type of data structure. This saves on converting numbers into ASCII that would be required by trace_marker. Suggested-by: Olof Johansson <olof@lixom.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
Родитель
9648dc1577
Коммит
fa32e8557b
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@ -396,6 +396,12 @@ of ftrace. Here is a list of some of the key files:
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trace_fd = open("trace_marker", WR_ONLY);
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trace_marker_raw:
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This is similar to trace_marker above, but is meant for for binary data
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to be written to it, where a tool can be used to parse the data
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from trace_pipe_raw.
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uprobe_events:
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Add dynamic tracepoints in programs.
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@ -4054,6 +4054,7 @@ static const char readme_msg[] =
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" x86-tsc: TSC cycle counter\n"
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#endif
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"\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
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"\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
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" tracing_cpumask\t- Limit which CPUs to trace\n"
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" instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
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"\t\t\t Remove sub-buffer with rmdir\n"
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@ -5514,35 +5515,15 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp)
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return 0;
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}
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static ssize_t
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tracing_mark_write(struct file *filp, const char __user *ubuf,
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size_t cnt, loff_t *fpos)
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static inline int lock_user_pages(const char __user *ubuf, size_t cnt,
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struct page **pages, void **map_page,
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int *offset)
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{
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unsigned long addr = (unsigned long)ubuf;
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struct trace_array *tr = filp->private_data;
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struct ring_buffer_event *event;
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struct ring_buffer *buffer;
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struct print_entry *entry;
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unsigned long irq_flags;
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struct page *pages[2];
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void *map_page[2];
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int nr_pages = 1;
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ssize_t written;
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int offset;
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int size;
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int len;
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int ret;
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int i;
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if (tracing_disabled)
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return -EINVAL;
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if (!(tr->trace_flags & TRACE_ITER_MARKERS))
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return -EINVAL;
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if (cnt > TRACE_BUF_SIZE)
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cnt = TRACE_BUF_SIZE;
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/*
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* Userspace is injecting traces into the kernel trace buffer.
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* We want to be as non intrusive as possible.
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@ -5557,26 +5538,70 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
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* pages directly. We then write the data directly into the
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* ring buffer.
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*/
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BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
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/* check if we cross pages */
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if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
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nr_pages = 2;
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offset = addr & (PAGE_SIZE - 1);
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*offset = addr & (PAGE_SIZE - 1);
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addr &= PAGE_MASK;
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ret = get_user_pages_fast(addr, nr_pages, 0, pages);
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if (ret < nr_pages) {
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while (--ret >= 0)
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put_page(pages[ret]);
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written = -EFAULT;
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goto out;
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return -EFAULT;
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}
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for (i = 0; i < nr_pages; i++)
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map_page[i] = kmap_atomic(pages[i]);
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return nr_pages;
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}
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static inline void unlock_user_pages(struct page **pages,
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void **map_page, int nr_pages)
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{
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int i;
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for (i = nr_pages - 1; i >= 0; i--) {
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kunmap_atomic(map_page[i]);
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put_page(pages[i]);
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}
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}
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static ssize_t
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tracing_mark_write(struct file *filp, const char __user *ubuf,
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size_t cnt, loff_t *fpos)
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{
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struct trace_array *tr = filp->private_data;
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struct ring_buffer_event *event;
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struct ring_buffer *buffer;
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struct print_entry *entry;
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unsigned long irq_flags;
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struct page *pages[2];
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void *map_page[2];
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int nr_pages = 1;
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ssize_t written;
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int offset;
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int size;
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int len;
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if (tracing_disabled)
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return -EINVAL;
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if (!(tr->trace_flags & TRACE_ITER_MARKERS))
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return -EINVAL;
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if (cnt > TRACE_BUF_SIZE)
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cnt = TRACE_BUF_SIZE;
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BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
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nr_pages = lock_user_pages(ubuf, cnt, pages, map_page, &offset);
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if (nr_pages < 0)
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return nr_pages;
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local_save_flags(irq_flags);
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size = sizeof(*entry) + cnt + 2; /* possible \n added */
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buffer = tr->trace_buffer.buffer;
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@ -5611,11 +5636,79 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
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*fpos += written;
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out_unlock:
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for (i = nr_pages - 1; i >= 0; i--) {
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kunmap_atomic(map_page[i]);
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put_page(pages[i]);
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unlock_user_pages(pages, map_page, nr_pages);
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return written;
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}
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/* Limit it for now to 3K (including tag) */
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#define RAW_DATA_MAX_SIZE (1024*3)
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static ssize_t
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tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
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size_t cnt, loff_t *fpos)
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{
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struct trace_array *tr = filp->private_data;
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struct ring_buffer_event *event;
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struct ring_buffer *buffer;
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struct raw_data_entry *entry;
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unsigned long irq_flags;
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struct page *pages[2];
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void *map_page[2];
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int nr_pages = 1;
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ssize_t written;
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int offset;
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int size;
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int len;
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if (tracing_disabled)
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return -EINVAL;
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if (!(tr->trace_flags & TRACE_ITER_MARKERS))
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return -EINVAL;
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/* The marker must at least have a tag id */
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if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
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return -EINVAL;
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if (cnt > TRACE_BUF_SIZE)
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cnt = TRACE_BUF_SIZE;
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BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
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nr_pages = lock_user_pages(ubuf, cnt, pages, map_page, &offset);
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if (nr_pages < 0)
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return nr_pages;
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local_save_flags(irq_flags);
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size = sizeof(*entry) + cnt;
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buffer = tr->trace_buffer.buffer;
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event = trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
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irq_flags, preempt_count());
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if (!event) {
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/* Ring buffer disabled, return as if not open for write */
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written = -EBADF;
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goto out_unlock;
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}
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out:
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entry = ring_buffer_event_data(event);
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if (nr_pages == 2) {
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len = PAGE_SIZE - offset;
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memcpy(&entry->id, map_page[0] + offset, len);
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memcpy(((char *)&entry->id) + len, map_page[1], cnt - len);
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} else
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memcpy(&entry->id, map_page[0] + offset, cnt);
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__buffer_unlock_commit(buffer, event);
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written = cnt;
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*fpos += written;
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out_unlock:
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unlock_user_pages(pages, map_page, nr_pages);
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return written;
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}
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@ -5945,6 +6038,13 @@ static const struct file_operations tracing_mark_fops = {
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.release = tracing_release_generic_tr,
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};
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static const struct file_operations tracing_mark_raw_fops = {
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.open = tracing_open_generic_tr,
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.write = tracing_mark_raw_write,
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.llseek = generic_file_llseek,
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.release = tracing_release_generic_tr,
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};
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static const struct file_operations trace_clock_fops = {
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.open = tracing_clock_open,
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.read = seq_read,
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@ -7214,6 +7314,9 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
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trace_create_file("trace_marker", 0220, d_tracer,
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tr, &tracing_mark_fops);
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trace_create_file("trace_marker_raw", 0220, d_tracer,
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tr, &tracing_mark_raw_fops);
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trace_create_file("trace_clock", 0644, d_tracer, tr,
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&trace_clock_fops);
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@ -40,6 +40,7 @@ enum trace_type {
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TRACE_BLK,
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TRACE_BPUTS,
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TRACE_HWLAT,
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TRACE_RAW_DATA,
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__TRACE_LAST_TYPE,
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};
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@ -331,6 +332,7 @@ extern void __ftrace_bad_type(void);
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IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \
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IF_ASSIGN(var, ent, struct bputs_entry, TRACE_BPUTS); \
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IF_ASSIGN(var, ent, struct hwlat_entry, TRACE_HWLAT); \
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IF_ASSIGN(var, ent, struct raw_data_entry, TRACE_RAW_DATA);\
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IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \
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TRACE_MMIO_RW); \
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IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
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@ -244,6 +244,21 @@ FTRACE_ENTRY(print, print_entry,
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FILTER_OTHER
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);
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FTRACE_ENTRY(raw_data, raw_data_entry,
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TRACE_RAW_DATA,
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F_STRUCT(
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__field( unsigned int, id )
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__dynamic_array( char, buf )
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),
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F_printk("id:%04x %08x",
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__entry->id, (int)__entry->buf[0]),
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FILTER_OTHER
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);
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FTRACE_ENTRY(bputs, bputs_entry,
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TRACE_BPUTS,
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@ -1288,6 +1288,35 @@ static struct trace_event trace_print_event = {
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.funcs = &trace_print_funcs,
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};
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static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
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struct trace_event *event)
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{
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struct raw_data_entry *field;
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int i;
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trace_assign_type(field, iter->ent);
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trace_seq_printf(&iter->seq, "# %x buf:", field->id);
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for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
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trace_seq_printf(&iter->seq, " %02x",
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(unsigned char)field->buf[i]);
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trace_seq_putc(&iter->seq, '\n');
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return trace_handle_return(&iter->seq);
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}
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static struct trace_event_functions trace_raw_data_funcs = {
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.trace = trace_raw_data,
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.raw = trace_raw_data,
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};
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static struct trace_event trace_raw_data_event = {
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.type = TRACE_RAW_DATA,
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.funcs = &trace_raw_data_funcs,
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};
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static struct trace_event *events[] __initdata = {
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&trace_fn_event,
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@ -1299,6 +1328,7 @@ static struct trace_event *events[] __initdata = {
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&trace_bprint_event,
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&trace_print_event,
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&trace_hwlat_event,
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&trace_raw_data_event,
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NULL
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};
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