[PATCH] perf: disable mmap2 support

[Stephane Eranian <eranian@google.com>]

This patch disables the mmap2 record format support
for now. The support needs a bit more work to cover
VM_CLONE cases.

The patch leaves attr->mmap2 defined, but returns
an error if it is set. That ensures no PERF_RECORD_MMAP2
record can be generated. Yet it minimizes the reverts in
the perf tool.


Signed-off-by: Stephane Eranian <eranian@google.com>
---
 include/uapi/linux/perf_event.h |   18 +-----------------
 kernel/events/core.c            |    4 ++++
 2 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index da48837..8074b29 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -682,23 +682,7 @@ enum perf_event_type {
 	PERF_RECORD_SAMPLE			= 9,
 
 	/*
-	 * The MMAP2 records are an augmented version of MMAP, they add
-	 * maj, min, ino numbers to be used to uniquely identify each mapping
-	 *
-	 * struct {
-	 *	struct perf_event_header	header;
-	 *
-	 *	u32				pid, tid;
-	 *	u64				addr;
-	 *	u64				len;
-	 *	u64				pgoff;
-	 *	u32				maj;
-	 *	u32				min;
-	 *	u64				ino;
-	 *	u64				ino_generation;
-	 *	char				filename[];
-	 * 	struct sample_id		sample_id;
-	 * };
+	 * reserved, do not use
 	 */
 	PERF_RECORD_MMAP2			= 10,
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c716385..d7152a6 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6782,6 +6782,10 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
 	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
 		return -EINVAL;
 
+	/* disable for now */
+	if (attr->mmap2)
+		return -EINVAL;
+
 	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
 		u64 mask = attr->branch_sample_type;
 
-- 
1.7.10.4