From: Andi Kleen <a...@linux.intel.com>
__output_copy always pads byte sized fields to a multiple
of u64. This was not documented in the perf_event.h documentation.
Explicitly mention this in the comments.
Also add notes that the strings are 0 terminated.
Only comments are changed.
Cc: eran...@google.com
Cc: pet...@infradead.org
Signed-off-by: Andi Kleen <a...@linux.intel.com>
---
include/uapi/linux/perf_event.h | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 2fc1602..06b2c8a 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -525,6 +525,7 @@ enum perf_event_type {
/*
* The MMAP events record the PROT_EXEC mappings so that we can
* correlate userspace IPs to code. They have the following structure:
+ * filename is zero terminated and padded to 8 bytes.
*
* struct {
* struct perf_event_header header;
@@ -533,7 +534,7 @@ enum perf_event_type {
* u64 addr;
* u64 len;
* u64 pgoff;
- * char filename[];
+ * char filename[ALIGN(len, 8)];
* struct sample_id sample_id;
* };
*/
@@ -549,12 +550,13 @@ enum perf_event_type {
*/
PERF_RECORD_LOST = 2,
- /*
+ /* comm is 0 terminated and padded to 8 bytes.
+ *
* struct {
* struct perf_event_header header;
*
* u32 pid, tid;
- * char comm[];
+ * char comm[ALIGN(len, 8)];
* struct sample_id sample_id;
* };
*/
@@ -637,12 +639,14 @@ enum perf_event_type {
* # the stability of its content, it may vary depending
* # on event, hardware, kernel version and phase of
* # the moon.
+ * #
+ * # data[size] is padded to 8 bytes.
* #
* # In other words, PERF_SAMPLE_RAW contents are not an ABI.
* #
*
* { u32 size;
- * char data[size];}&& PERF_SAMPLE_RAW
+ * char data[ALIGN(size, 8)];}&& PERF_SAMPLE_RAW
*
* { u64 nr;
* { u64 from, to, flags } lbr[nr];} && PERF_SAMPLE_BRANCH_STACK
@@ -651,7 +655,7 @@ enum perf_event_type {
* u64 regs[weight(mask)]; } &&
PERF_SAMPLE_REGS_USER
*
* { u64 size;
- * char data[size];
+ * char data[ALIGN(size, 8)];
* u64 dyn_size; } && PERF_SAMPLE_STACK_USER
*
* { u64 weight; } && PERF_SAMPLE_WEIGHT
@@ -663,6 +667,7 @@ enum perf_event_type {
/*
* The MMAP2 records are an augmented version of MMAP, they add
* maj, min, ino numbers to be used to uniquely identify each mapping
+ * filename is 0 terminated and padded to 8 bytes.
*
* struct {
* struct perf_event_header header;
@@ -675,7 +680,7 @@ enum perf_event_type {
* u32 min;
* u64 ino;
* u64 ino_generation;
- * char filename[];
+ * char filename[ALIGN(len, 8)];
* struct sample_id sample_id;
* };
*/
--
1.8.3.1
--
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