140 lines
4.6 KiB
Diff
140 lines
4.6 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
|
Date: Mon, 28 Aug 2017 08:47:21 +0200
|
|
Subject: [PATCH] x86/tracing: Introduce a static key for exception tracing
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
CVE-2017-5754
|
|
|
|
Switching the IDT just for avoiding tracepoints creates a completely
|
|
impenetrable macro/inline/ifdef mess.
|
|
|
|
There is no point in avoiding tracepoints for most of the traps/exceptions.
|
|
For the more expensive tracepoints, like pagefaults, this can be handled with
|
|
an explicit static key.
|
|
|
|
Preparatory patch to remove the tracing IDT.
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Cc: Andy Lutomirski <luto@kernel.org>
|
|
Cc: Borislav Petkov <bp@alien8.de>
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
Cc: Steven Rostedt <rostedt@goodmis.org>
|
|
Link: http://lkml.kernel.org/r/20170828064956.593094539@linutronix.de
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
(cherry picked from commit 2feb1b316d48004d905278c02a55902cab0be8be)
|
|
Signed-off-by: Andy Whitcroft <apw@kathleen.maas>
|
|
(cherry picked from commit 15e0ff2a63fdd93f8881e2ebba5c048c5b601e57)
|
|
Signed-off-by: Andy Whitcroft <apw@canonical.com>
|
|
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
|
|
(cherry picked from commit d58a56e851c339d8d9d311dc9b4fad6abbf8bf19)
|
|
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
|
|
---
|
|
arch/x86/include/asm/trace/common.h | 15 +++++++++++++++
|
|
arch/x86/include/asm/trace/exceptions.h | 4 +---
|
|
arch/x86/include/asm/trace/irq_vectors.h | 4 +---
|
|
arch/x86/kernel/tracepoint.c | 9 ++++++++-
|
|
4 files changed, 25 insertions(+), 7 deletions(-)
|
|
create mode 100644 arch/x86/include/asm/trace/common.h
|
|
|
|
diff --git a/arch/x86/include/asm/trace/common.h b/arch/x86/include/asm/trace/common.h
|
|
new file mode 100644
|
|
index 000000000000..b1eb7b18ee8a
|
|
--- /dev/null
|
|
+++ b/arch/x86/include/asm/trace/common.h
|
|
@@ -0,0 +1,15 @@
|
|
+#ifndef _ASM_TRACE_COMMON_H
|
|
+#define _ASM_TRACE_COMMON_H
|
|
+
|
|
+extern int trace_irq_vector_regfunc(void);
|
|
+extern void trace_irq_vector_unregfunc(void);
|
|
+
|
|
+#ifdef CONFIG_TRACING
|
|
+DECLARE_STATIC_KEY_FALSE(trace_irqvectors_key);
|
|
+#define trace_irqvectors_enabled() \
|
|
+ static_branch_unlikely(&trace_irqvectors_key)
|
|
+#else
|
|
+static inline bool trace_irqvectors_enabled(void) { return false; }
|
|
+#endif
|
|
+
|
|
+#endif
|
|
diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
|
|
index 2422b14c50a7..960a5b50ac3b 100644
|
|
--- a/arch/x86/include/asm/trace/exceptions.h
|
|
+++ b/arch/x86/include/asm/trace/exceptions.h
|
|
@@ -5,9 +5,7 @@
|
|
#define _TRACE_PAGE_FAULT_H
|
|
|
|
#include <linux/tracepoint.h>
|
|
-
|
|
-extern int trace_irq_vector_regfunc(void);
|
|
-extern void trace_irq_vector_unregfunc(void);
|
|
+#include <asm/trace/common.h>
|
|
|
|
DECLARE_EVENT_CLASS(x86_exceptions,
|
|
|
|
diff --git a/arch/x86/include/asm/trace/irq_vectors.h b/arch/x86/include/asm/trace/irq_vectors.h
|
|
index 32dd6a9e343c..7825b4426e7e 100644
|
|
--- a/arch/x86/include/asm/trace/irq_vectors.h
|
|
+++ b/arch/x86/include/asm/trace/irq_vectors.h
|
|
@@ -5,9 +5,7 @@
|
|
#define _TRACE_IRQ_VECTORS_H
|
|
|
|
#include <linux/tracepoint.h>
|
|
-
|
|
-extern int trace_irq_vector_regfunc(void);
|
|
-extern void trace_irq_vector_unregfunc(void);
|
|
+#include <asm/trace/common.h>
|
|
|
|
DECLARE_EVENT_CLASS(x86_irq_vector,
|
|
|
|
diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c
|
|
index 15515132bf0d..dd4aa04bb95c 100644
|
|
--- a/arch/x86/kernel/tracepoint.c
|
|
+++ b/arch/x86/kernel/tracepoint.c
|
|
@@ -4,9 +4,11 @@
|
|
* Copyright (C) 2013 Seiji Aguchi <seiji.aguchi@hds.com>
|
|
*
|
|
*/
|
|
+#include <linux/jump_label.h>
|
|
+#include <linux/atomic.h>
|
|
+
|
|
#include <asm/hw_irq.h>
|
|
#include <asm/desc.h>
|
|
-#include <linux/atomic.h>
|
|
|
|
atomic_t trace_idt_ctr = ATOMIC_INIT(0);
|
|
struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
|
|
@@ -15,6 +17,7 @@ struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
|
|
/* No need to be aligned, but done to keep all IDTs defined the same way. */
|
|
gate_desc trace_idt_table[NR_VECTORS] __page_aligned_bss;
|
|
|
|
+DEFINE_STATIC_KEY_FALSE(trace_irqvectors_key);
|
|
static int trace_irq_vector_refcount;
|
|
static DEFINE_MUTEX(irq_vector_mutex);
|
|
|
|
@@ -36,6 +39,8 @@ static void switch_idt(void *arg)
|
|
|
|
int trace_irq_vector_regfunc(void)
|
|
{
|
|
+ static_branch_inc(&trace_irqvectors_key);
|
|
+
|
|
mutex_lock(&irq_vector_mutex);
|
|
if (!trace_irq_vector_refcount) {
|
|
set_trace_idt_ctr(1);
|
|
@@ -49,6 +54,8 @@ int trace_irq_vector_regfunc(void)
|
|
|
|
void trace_irq_vector_unregfunc(void)
|
|
{
|
|
+ static_branch_dec(&trace_irqvectors_key);
|
|
+
|
|
mutex_lock(&irq_vector_mutex);
|
|
trace_irq_vector_refcount--;
|
|
if (!trace_irq_vector_refcount) {
|
|
--
|
|
2.14.2
|
|
|