locking/mutex: Disable optimistic spinning on some architectures

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 <peterz@infradead.org>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: John David Anglin <dave.anglin@bell.net>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2:
 - Adjust context
 - Drop arm64 change]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 790ea68..082bd36 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1,6 +1,7 @@
 config ARM
        bool
        default y
+       select ARCH_SUPPORTS_ATOMIC_RMW
        select HAVE_DMA_API_DEBUG
        select HAVE_IDE if PCI || ISA || PCMCIA
        select HAVE_MEMBLOCK

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 16ef838..bec952d 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -137,6 +137,7 @@ config PPC
        select HAVE_BPF_JIT if (PPC64 && NET)
        select HAVE_ARCH_JUMP_LABEL
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
+       select ARCH_SUPPORTS_ATOMIC_RMW
 
 config EARLY_PRINTK
        bool

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 88d442d..f2f3574 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -57,6 +57,7 @@ config SPARC64
        select IRQ_PREFLOW_FASTEOI
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select HAVE_C_RECORDMCOUNT
+       select ARCH_SUPPORTS_ATOMIC_RMW
 
 config ARCH_DEFCONFIG
        string

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fb2e69d..901447e 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -75,6 +75,7 @@ config X86
        select HAVE_BPF_JIT if (X86_64 && NET)
        select CLKEVT_I8253
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
+       select ARCH_SUPPORTS_ATOMIC_RMW
 
 config INSTRUCTION_DECODER
        def_bool (KPROBES || PERF_EVENTS)

diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index 5068e2a..61ebb49 100644 (file)
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -198,5 +198,9 @@ config INLINE_WRITE_UNLOCK_IRQ
 config INLINE_WRITE_UNLOCK_IRQRESTORE
        def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 
+config ARCH_SUPPORTS_ATOMIC_RMW
+       bool
+
 config MUTEX_SPIN_ON_OWNER
-       def_bool SMP && !DEBUG_MUTEXES
+       def_bool y
+       depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW