Implement branch tracing on Linux based on perf_event such that it can be shared

between gdb and gdbserver.

gdb/
	* common/linux_btrace.h: New file.
	* common/linux_btrace.c: New file.
	* Makefile.in (SFILES): Add btrace.c.
	(HFILES_NO_SRCDIR): Add common/linux-btrace.h.
	(COMMON_OBS): Add btrace.o.
	(linux-btrace.o): New rule.

gdbserver/
	* Makefile.in (SFILES): Add $(srcdir)/common/linux-btrace.c.
	(linux_btrace_h): New variable.
	(linux-btrace.o): New rule.

1 files changed, 77 insertions, 0 deletions

diff --git a/gdb/common/linux-btrace.h b/gdb/common/linux-btrace.h
new file mode 100644
index 0000000..d4e8402
--- /dev/null
+++ b/gdb/common/linux-btrace.h
@@ -0,0 +1,77 @@
+/* Linux-dependent part of branch trace support for GDB, and GDBserver.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   Contributed by Intel Corp. <markus.t.metzger@intel.com>
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef LINUX_BTRACE_H
+#define LINUX_BTRACE_H
+
+#include "btrace-common.h"
+#include "config.h"
+#include "vec.h"
+#include "ptid.h"
+#include <stddef.h>
+#include <stdint.h>
+
+#if HAVE_LINUX_PERF_EVENT_H
+#  include <linux/perf_event.h>
+#endif
+
+/* Branch trace target information per thread.  */
+struct btrace_target_info
+{
+#if HAVE_LINUX_PERF_EVENT_H
+  /* The Linux perf_event configuration for collecting the branch trace.  */
+  struct perf_event_attr attr;
+
+  /* The ptid of this thread.  */
+  ptid_t ptid;
+
+  /* The mmap configuration mapping the branch trace perf_event buffer.
+
+     file      .. the file descriptor
+     buffer    .. the mmapped memory buffer
+     size      .. the buffer's size in pages without the configuration page
+     data_head .. the data head from the last read  */
+  int file;
+  void *buffer;
+  size_t size;
+  unsigned long data_head;
+#endif /* HAVE_LINUX_PERF_EVENT_H */
+
+  /* The size of a pointer in bits for this thread.
+     The information is used to identify kernel addresses in order to skip
+     records from/to kernel space.  */
+  int ptr_bits;
+};
+
+/* Check whether branch tracing is supported.  */
+extern int linux_supports_btrace (void);
+
+/* Enable branch tracing for @ptid.  */
+extern struct btrace_target_info *linux_enable_btrace (ptid_t ptid);
+
+/* Disable branch tracing and deallocate @tinfo.  */
+extern int linux_disable_btrace (struct btrace_target_info *tinfo);
+
+/* Read branch trace data.  */
+extern VEC (btrace_block_s) *linux_read_btrace (struct btrace_target_info *,
+						enum btrace_read_type);
+
+#endif /* LINUX_BTRACE_H */