From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Thu, 3 Aug 2017 11:38:21 +0900
Subject: [PATCH] irq: Make the irqentry text section unconditional
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CVE-2017-5754

Generate irqentry and softirqentry text sections without
any Kconfig dependencies. This will add extra sections, but
there should be no performace impact.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David S . Miller <davem@davemloft.net>
Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-arch@vger.kernel.org
Cc: linux-cris-kernel@axis.com
Cc: mathieu.desnoyers@efficios.com
Link: http://lkml.kernel.org/r/150172789110.27216.3955739126693102122.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit 229a71860547ec856b156179a9c6bef2de426f66)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit 8fd2f68cc93ae772cfddf4151d13448ff17d0229)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/arm/include/asm/traps.h      |  7 -------
 arch/arm64/include/asm/traps.h    |  7 -------
 include/asm-generic/sections.h    |  4 ++++
 include/asm-generic/vmlinux.lds.h |  8 --------
 include/linux/interrupt.h         | 14 +-------------
 arch/x86/kernel/unwind_frame.c    |  2 --
 arch/x86/entry/entry_64.S         |  9 ++-------
 7 files changed, 7 insertions(+), 44 deletions(-)

diff --git a/arch/arm/include/asm/traps.h b/arch/arm/include/asm/traps.h
index f555bb3664dc..683d9230984a 100644
--- a/arch/arm/include/asm/traps.h
+++ b/arch/arm/include/asm/traps.h
@@ -18,7 +18,6 @@ struct undef_hook {
 void register_undef_hook(struct undef_hook *hook);
 void unregister_undef_hook(struct undef_hook *hook);
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static inline int __in_irqentry_text(unsigned long ptr)
 {
 	extern char __irqentry_text_start[];
@@ -27,12 +26,6 @@ static inline int __in_irqentry_text(unsigned long ptr)
 	return ptr >= (unsigned long)&__irqentry_text_start &&
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
-#else
-static inline int __in_irqentry_text(unsigned long ptr)
-{
-	return 0;
-}
-#endif
 
 static inline int in_exception_text(unsigned long ptr)
 {
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 02e9035b0685..47a9066f7c86 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -37,18 +37,11 @@ void unregister_undef_hook(struct undef_hook *hook);
 
 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr);
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static inline int __in_irqentry_text(unsigned long ptr)
 {
 	return ptr >= (unsigned long)&__irqentry_text_start &&
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
-#else
-static inline int __in_irqentry_text(unsigned long ptr)
-{
-	return 0;
-}
-#endif
 
 static inline int in_exception_text(unsigned long ptr)
 {
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 532372c6cf15..e5da44eddd2f 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -27,6 +27,8 @@
  *	__kprobes_text_start, __kprobes_text_end
  *	__entry_text_start, __entry_text_end
  *	__ctors_start, __ctors_end
+ *	__irqentry_text_start, __irqentry_text_end
+ *	__softirqentry_text_start, __softirqentry_text_end
  */
 extern char _text[], _stext[], _etext[];
 extern char _data[], _sdata[], _edata[];
@@ -39,6 +41,8 @@ extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
 extern char __kprobes_text_start[], __kprobes_text_end[];
 extern char __entry_text_start[], __entry_text_end[];
 extern char __start_rodata[], __end_rodata[];
+extern char __irqentry_text_start[], __irqentry_text_end[];
+extern char __softirqentry_text_start[], __softirqentry_text_end[];
 
 /* Start and end of .ctors section - used for constructor calls. */
 extern char __ctors_start[], __ctors_end[];
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 9623d78f8494..e7e955d4ab9e 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -497,25 +497,17 @@
 		*(.entry.text)						\
 		VMLINUX_SYMBOL(__entry_text_end) = .;
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 #define IRQENTRY_TEXT							\
 		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__irqentry_text_start) = .;		\
 		*(.irqentry.text)					\
 		VMLINUX_SYMBOL(__irqentry_text_end) = .;
-#else
-#define IRQENTRY_TEXT
-#endif
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 #define SOFTIRQENTRY_TEXT						\
 		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__softirqentry_text_start) = .;		\
 		*(.softirqentry.text)					\
 		VMLINUX_SYMBOL(__softirqentry_text_end) = .;
-#else
-#define SOFTIRQENTRY_TEXT
-#endif
 
 /* Section used for early init (in .S files) */
 #define HEAD_TEXT  *(.head.text)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index a2fddddb0d60..59ba11661b6e 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -18,6 +18,7 @@
 #include <linux/atomic.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
+#include <asm/sections.h>
 
 /*
  * These correspond to the IORESOURCE_IRQ_* defines in
@@ -726,7 +727,6 @@ extern int early_irq_init(void);
 extern int arch_probe_nr_irqs(void);
 extern int arch_early_irq_init(void);
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 /*
  * We want to know which function is an entrypoint of a hardirq or a softirq.
  */
@@ -734,16 +734,4 @@ extern int arch_early_irq_init(void);
 #define __softirq_entry  \
 	__attribute__((__section__(".softirqentry.text")))
 
-/* Limits of hardirq entrypoints */
-extern char __irqentry_text_start[];
-extern char __irqentry_text_end[];
-/* Limits of softirq entrypoints */
-extern char __softirqentry_text_start[];
-extern char __softirqentry_text_end[];
-
-#else
-#define __irq_entry
-#define __softirq_entry
-#endif
-
 #endif
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index b9389d72b2f7..c29e5bc7e9c9 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -91,10 +91,8 @@ static bool in_entry_code(unsigned long ip)
 	if (addr >= __entry_text_start && addr < __entry_text_end)
 		return true;
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 	if (addr >= __irqentry_text_start && addr < __irqentry_text_end)
 		return true;
-#endif
 
 	return false;
 }
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 4dbb336a1fdd..ca0b250eefc4 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -761,13 +761,8 @@ apicinterrupt3 \num trace(\sym) smp_trace(\sym)
 #endif
 
 /* Make sure APIC interrupt handlers end up in the irqentry section: */
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
-# define PUSH_SECTION_IRQENTRY	.pushsection .irqentry.text, "ax"
-# define POP_SECTION_IRQENTRY	.popsection
-#else
-# define PUSH_SECTION_IRQENTRY
-# define POP_SECTION_IRQENTRY
-#endif
+#define PUSH_SECTION_IRQENTRY	.pushsection .irqentry.text, "ax"
+#define POP_SECTION_IRQENTRY	.popsection
 
 .macro apicinterrupt num sym do_sym
 PUSH_SECTION_IRQENTRY
-- 
2.14.2

