lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Mon, 20 Feb 2017 15:33:51 +0200
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...hat.com>
Cc:     linux-kernel@...r.kernel.org, vince@...ter.net, eranian@...gle.com,
        Arnaldo Carvalho de Melo <acme@...radead.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
Subject: [PATCH 3/4] perf: Add a flag for partial AUX records

Intel PT driver needs to be able to communicate partial AUX transactions,
that is, transactions with gaps in data for reasons other than no room
left in the buffer (i.e. truncated transactions). Therefore, this condition
does not imply a wakeup for the consumer.

To this end, add a new "partial" AUX flag.

Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
---
 include/uapi/linux/perf_event.h | 1 +
 kernel/events/ring_buffer.c     | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index c66a485a24..8306415207 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -885,6 +885,7 @@ enum perf_callchain_context {
  */
 #define PERF_AUX_FLAG_TRUNCATED		0x01	/* record was truncated to fit */
 #define PERF_AUX_FLAG_OVERWRITE		0x02	/* snapshot from overwrite mode */
+#define PERF_AUX_FLAG_PARTIAL		0x04	/* record contains gaps */
 
 #define PERF_FLAG_FD_NO_GROUP		(1UL << 0)
 #define PERF_FLAG_FD_OUTPUT		(1UL << 1)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index f3ebafe060..cd5e902a27 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -425,8 +425,8 @@ EXPORT_SYMBOL_GPL(perf_aux_output_begin);
  */
 void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
 {
+	bool wakeup = !!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED);
 	struct ring_buffer *rb = handle->rb;
-	bool wakeup = !!handle->aux_flags;
 	unsigned long aux_head;
 
 	/* in overwrite mode, driver provides aux_head via handle */
-- 
2.11.0

Powered by blists - more mailing lists