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Subject[PATCH] perf, ibs: Check syscall attribute flags
On 06.09.12 21:56:45, Robert Richter wrote:
> I tested the patch and it runs ok with my kernel patch that checks
> syscall attributes for ibs. perf tools falls back and clears
> exclude_guest/_host bits in attr.

This is the patch that checks syscall attributes for ibs. Should be
for tip:perf/urgent for ABI compatibility.

-Robert


From 1d037614edef576da441936bd8c917d31f57b179 Mon Sep 17 00:00:00 2001
From: Robert Richter <robert.richter@amd.com>
Date: Wed, 25 Jul 2012 19:12:45 +0200
Subject: [PATCH] perf, ibs: Check syscall attribute flags

Current implementation simply ignores attribute flags. Thus, there is
no notification to userland of unsupported features. Check syscall's
attribute flags to let userland know if a feature is supported by the
kernel. This is also needed to distinguish between future kernels what
might support a feature.

Cc: <stable@vger.kernel.org> v3.5..
Signed-off-by: Robert Richter <robert.richter@amd.com>
---
arch/x86/kernel/cpu/perf_event_amd_ibs.c | 11 +++++++++++
include/linux/perf_event.h | 2 ++
2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index 7bfb5be..0456061 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -215,6 +215,14 @@ static int perf_ibs_init(struct perf_event *event)
struct perf_ibs *perf_ibs;
u64 max_cnt, config;
int ret;
+ struct perf_event_attr notsupp = {
+ .exclude_user = 1,
+ .exclude_kernel = 1,
+ .exclude_hv = 1,
+ .exclude_idle = 1,
+ .exclude_host = 1,
+ .exclude_guest = 1,
+ };

perf_ibs = get_ibs_pmu(event->attr.type);
if (perf_ibs) {
@@ -229,6 +237,9 @@ static int perf_ibs_init(struct perf_event *event)
if (event->pmu != &perf_ibs->pmu)
return -ENOENT;

+ if (perf_flags(&event->attr) & perf_flags(&notsupp))
+ return -EINVAL;
+
if (config & ~perf_ibs->config_mask)
return -EINVAL;

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 28f9cee..c36a04f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -304,6 +304,8 @@ struct perf_event_attr {
__u32 __reserved_2;
};

+#define perf_flags(attr) (*(&(attr)->read_format + 1))
+
/*
* Ioctls that can be done on a perf event fd:
*/
--
1.7.8.6



--
Advanced Micro Devices, Inc.
Operating System Research Center



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