linux-kernel - [tip:perf/core] perf/x86/intel/pt: Add interface to stop Intel PT logging

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 linux-cve-announce 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]

Message-ID: <tip-24cc12b17679f8e9046746f92fd377f589efc163@git.kernel.org>
Date:	Mon, 23 Nov 2015 08:25:30 -0800
From:	tip-bot for Takao Indoh <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	indou.takao@...fujitsu.com, mingo@...nel.org,
	vincent.weaver@...ne.edu, eranian@...gle.com, vgoyal@...hat.com,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, efault@....de,
	peterz@...radead.org, acme@...nel.org, hpa@...or.com,
	torvalds@...ux-foundation.org, alexander.shishkin@...ux.intel.com,
	acme@...hat.com, jolsa@...hat.com
Subject: [tip:perf/core] perf/x86/intel/pt:
  Add interface to stop Intel PT logging

Commit-ID:  24cc12b17679f8e9046746f92fd377f589efc163
Gitweb:     http://git.kernel.org/tip/24cc12b17679f8e9046746f92fd377f589efc163
Author:     Takao Indoh <indou.takao@...fujitsu.com>
AuthorDate: Wed, 4 Nov 2015 14:22:32 +0900
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 23 Nov 2015 09:58:26 +0100

perf/x86/intel/pt: Add interface to stop Intel PT logging

This patch add a function for external components to stop Intel PT.
Basically this function is used when kernel panic occurs. When it is
called, the intel_pt driver disables Intel PT and saves its registers
using pt_event_stop(), which is also used by pmu.stop handler.

This function stops Intel PT on the CPU where it is working, therefore
users of it need to call it for each CPU to stop all logging.

Signed-off-by: Takao Indoh <indou.takao@...fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Alexander Shishkin<alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: H.Peter Anvin <hpa@...or.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mike Galbraith <efault@....de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Cc: Vivek Goyal <vgoyal@...hat.com>
Link: http://lkml.kernel.org/r/1446614553-6072-2-git-send-email-indou.takao@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/intel_pt.h           | 10 ++++++++++
 arch/x86/kernel/cpu/perf_event_intel_pt.c |  9 +++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h
new file mode 100644
index 0000000..e1a4117
--- /dev/null
+++ b/arch/x86/include/asm/intel_pt.h
@@ -0,0 +1,10 @@
+#ifndef _ASM_X86_INTEL_PT_H
+#define _ASM_X86_INTEL_PT_H
+
+#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
+void cpu_emergency_stop_pt(void);
+#else
+static inline void cpu_emergency_stop_pt(void) {}
+#endif
+
+#endif /* _ASM_X86_INTEL_PT_H */
diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
index 868e119..c0bbd10 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
@@ -27,6 +27,7 @@
 #include <asm/perf_event.h>
 #include <asm/insn.h>
 #include <asm/io.h>
+#include <asm/intel_pt.h>
 
 #include "perf_event.h"
 #include "intel_pt.h"
@@ -1122,6 +1123,14 @@ static int pt_event_init(struct perf_event *event)
 	return 0;
 }
 
+void cpu_emergency_stop_pt(void)
+{
+	struct pt *pt = this_cpu_ptr(&pt_ctx);
+
+	if (pt->handle.event)
+		pt_event_stop(pt->handle.event, PERF_EF_UPDATE);
+}
+
 static __init int pt_init(void)
 {
 	int ret, cpu, prior_warn = 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/