[added,to,the,3.12,stable,tree] locking/mutex: Disable optimistic spinning on some architectures

Commit Message

Jiri Slaby July 29, 2014, 3:09 p.m. UTC

From: Peter Zijlstra <[e-mail]>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

Patch

===============

commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc upstream.

The optimistic spin code assumes regular stores and cmpxchg() play nice;
this is found to not be true for at least: parisc, sparc32, tile32,
metag-lock1, arc-!llsc and hexagon.

There is further wreckage, but this in particular seemed easy to
trigger, so blacklist this.

Opt in for known good archs.

Signed-off-by: Peter Zijlstra <[e-mail]>
Reported-by: Mikulas Patocka <[e-mail]>
Cc: David Miller <[e-mail]>
Cc: Chris Metcalf <[e-mail]>
Cc: James Bottomley <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: Jason Low <[e-mail]>
Cc: Waiman Long <[e-mail]>
Cc: "James E.J. Bottomley" <[e-mail]>
Cc: Paul McKenney <[e-mail]>
Cc: John David Anglin <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Davidlohr Bueso <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>
Signed-off-by: Jiri Slaby <[e-mail]>
---
 arch/arm/Kconfig     | 1 +
 arch/arm64/Kconfig   | 1 +
 arch/powerpc/Kconfig | 1 +
 arch/sparc/Kconfig   | 1 +
 arch/x86/Kconfig     | 1 +
 kernel/Kconfig.locks | 5 ++++-
 6 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e47fcd1e9645..99e1ce978cf9 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -5,6 +5,7 @@  config ARM
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_CUSTOM_GPIO_H
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c04454876bcb..fe70eaea0e28 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1,6 +1,7 @@ 
 config ARM64
 	def_bool y
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
 	select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d5d026b6d237..2e0ddfadc0b9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -138,6 +138,7 @@  config PPC
 	select OLD_SIGSUSPEND
 	select OLD_SIGACTION if PPC32
 	select HAVE_DEBUG_STACKOVERFLOW
+	select ARCH_SUPPORTS_ATOMIC_RMW
 
 config EARLY_PRINTK
 	bool
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 4e5683877b93..d60f34dbae89 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -75,6 +75,7 @@  config SPARC64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_C_RECORDMCOUNT
 	select NO_BOOTMEM
+	select ARCH_SUPPORTS_ATOMIC_RMW
 
 config ARCH_DEFCONFIG
 	string
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index eb2dfa61eabe..9dc1a24d41b8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -123,6 +123,7 @@  config X86
 	select COMPAT_OLD_SIGACTION if IA32_EMULATION
 	select RTC_LIB
 	select HAVE_DEBUG_STACKOVERFLOW
+	select ARCH_SUPPORTS_ATOMIC_RMW
 
 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index d2b32ac27a39..ecee67a00f5f 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -220,6 +220,9 @@  config INLINE_WRITE_UNLOCK_IRQRESTORE
 
 endif
 
+config ARCH_SUPPORTS_ATOMIC_RMW
+	bool
+
 config MUTEX_SPIN_ON_OWNER
 	def_bool y
-	depends on SMP && !DEBUG_MUTEXES
+	depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW