queue-3.0/arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
queue-3.4/arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
queue-3.5/arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
+++ /dev/null
-From a76d7bd96d65fa5119adba97e1b58d95f2e78829 Mon Sep 17 00:00:00 2001
-From: Will Deacon <will.deacon@arm.com>
-Date: Fri, 13 Jul 2012 19:15:40 +0100
-Subject: ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+
-
-From: Will Deacon <will.deacon@arm.com>
-
-commit a76d7bd96d65fa5119adba97e1b58d95f2e78829 upstream.
-
-The open-coded mutex implementation for ARMv6+ cores suffers from a
-severe lack of barriers, so in the uncontended case we don't actually
-protect any accesses performed during the critical section.
-
-Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec
-code but optimised to remove a branch instruction, as the mutex fastpath
-was previously inlined. Now that this is executed out-of-line, we can
-reuse the atomic access code for the locking (in fact, we use the xchg
-code as this produces shorter critical sections).
-
-This patch uses the generic xchg based implementation for mutexes on
-ARMv6+, which introduces barriers to the lock/unlock operations and also
-has the benefit of removing a fair amount of inline assembly code.
-
-Acked-by: Arnd Bergmann <arnd@arndb.de>
-Acked-by: Nicolas Pitre <nico@linaro.org>
-Reported-by: Shan Kang <kangshan0910@gmail.com>
-Signed-off-by: Will Deacon <will.deacon@arm.com>
-Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- arch/arm/include/asm/mutex.h | 119 +------------------------------------------
- 1 file changed, 4 insertions(+), 115 deletions(-)
-
---- a/arch/arm/include/asm/mutex.h
-+++ b/arch/arm/include/asm/mutex.h
-@@ -7,121 +7,10 @@
- */
- #ifndef _ASM_MUTEX_H
- #define _ASM_MUTEX_H
--
--#if __LINUX_ARM_ARCH__ < 6
--/* On pre-ARMv6 hardware the swp based implementation is the most efficient. */
--# include <asm-generic/mutex-xchg.h>
--#else
--
- /*
-- * Attempting to lock a mutex on ARMv6+ can be done with a bastardized
-- * atomic decrement (it is not a reliable atomic decrement but it satisfies
-- * the defined semantics for our purpose, while being smaller and faster
-- * than a real atomic decrement or atomic swap. The idea is to attempt
-- * decrementing the lock value only once. If once decremented it isn't zero,
-- * or if its store-back fails due to a dispute on the exclusive store, we
-- * simply bail out immediately through the slow path where the lock will be
-- * reattempted until it succeeds.
-+ * On pre-ARMv6 hardware this results in a swp-based implementation,
-+ * which is the most efficient. For ARMv6+, we emit a pair of exclusive
-+ * accesses instead.
- */
--static inline void
--__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- fail_fn(count);
--}
--
--static inline int
--__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- __res = fail_fn(count);
-- return __res;
--}
--
--/*
-- * Same trick is used for the unlock fast path. However the original value,
-- * rather than the result, is used to test for success in order to have
-- * better generated assembly.
-- */
--static inline void
--__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "ldrex %0, [%3] \n\t"
-- "add %1, %0, #1 \n\t"
-- "strex %2, %1, [%3] "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __orig |= __ex_flag;
-- if (unlikely(__orig != 0))
-- fail_fn(count);
--}
--
--/*
-- * If the unlock was done on a contended lock, or if the unlock simply fails
-- * then the mutex remains locked.
-- */
--#define __mutex_slowpath_needs_to_unlock() 1
--
--/*
-- * For __mutex_fastpath_trylock we use another construct which could be
-- * described as a "single value cmpxchg".
-- *
-- * This provides the needed trylock semantics like cmpxchg would, but it is
-- * lighter and less generic than a true cmpxchg implementation.
-- */
--static inline int
--__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "1: ldrex %0, [%3] \n\t"
-- "subs %1, %0, #1 \n\t"
-- "strexeq %2, %1, [%3] \n\t"
-- "movlt %0, #0 \n\t"
-- "cmpeq %2, #0 \n\t"
-- "bgt 1b "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&count->counter)
-- : "cc", "memory" );
--
-- return __orig;
--}
--
--#endif
-+#include <asm-generic/mutex-xchg.h>
- #endif
nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch
pcdp-use-early_ioremap-early_iounmap-to-access-pcdp-table.patch
mm-fix-wrong-argument-of-migrate_huge_pages-in-soft_offline_huge_page.patch
-arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
arm-7478-1-errata-extend-workaround-for-erratum-720789.patch
arm-7479-1-mm-avoid-null-dereference-when-flushing-gate_vma-with-vivt-caches.patch
mm-mmu_notifier-fix-freed-page-still-mapped-in-secondary-mmu.patch
+++ /dev/null
-From a76d7bd96d65fa5119adba97e1b58d95f2e78829 Mon Sep 17 00:00:00 2001
-From: Will Deacon <will.deacon@arm.com>
-Date: Fri, 13 Jul 2012 19:15:40 +0100
-Subject: ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+
-
-From: Will Deacon <will.deacon@arm.com>
-
-commit a76d7bd96d65fa5119adba97e1b58d95f2e78829 upstream.
-
-The open-coded mutex implementation for ARMv6+ cores suffers from a
-severe lack of barriers, so in the uncontended case we don't actually
-protect any accesses performed during the critical section.
-
-Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec
-code but optimised to remove a branch instruction, as the mutex fastpath
-was previously inlined. Now that this is executed out-of-line, we can
-reuse the atomic access code for the locking (in fact, we use the xchg
-code as this produces shorter critical sections).
-
-This patch uses the generic xchg based implementation for mutexes on
-ARMv6+, which introduces barriers to the lock/unlock operations and also
-has the benefit of removing a fair amount of inline assembly code.
-
-Acked-by: Arnd Bergmann <arnd@arndb.de>
-Acked-by: Nicolas Pitre <nico@linaro.org>
-Reported-by: Shan Kang <kangshan0910@gmail.com>
-Signed-off-by: Will Deacon <will.deacon@arm.com>
-Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- arch/arm/include/asm/mutex.h | 119 +------------------------------------------
- 1 file changed, 4 insertions(+), 115 deletions(-)
-
---- a/arch/arm/include/asm/mutex.h
-+++ b/arch/arm/include/asm/mutex.h
-@@ -7,121 +7,10 @@
- */
- #ifndef _ASM_MUTEX_H
- #define _ASM_MUTEX_H
--
--#if __LINUX_ARM_ARCH__ < 6
--/* On pre-ARMv6 hardware the swp based implementation is the most efficient. */
--# include <asm-generic/mutex-xchg.h>
--#else
--
- /*
-- * Attempting to lock a mutex on ARMv6+ can be done with a bastardized
-- * atomic decrement (it is not a reliable atomic decrement but it satisfies
-- * the defined semantics for our purpose, while being smaller and faster
-- * than a real atomic decrement or atomic swap. The idea is to attempt
-- * decrementing the lock value only once. If once decremented it isn't zero,
-- * or if its store-back fails due to a dispute on the exclusive store, we
-- * simply bail out immediately through the slow path where the lock will be
-- * reattempted until it succeeds.
-+ * On pre-ARMv6 hardware this results in a swp-based implementation,
-+ * which is the most efficient. For ARMv6+, we emit a pair of exclusive
-+ * accesses instead.
- */
--static inline void
--__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- fail_fn(count);
--}
--
--static inline int
--__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- __res = fail_fn(count);
-- return __res;
--}
--
--/*
-- * Same trick is used for the unlock fast path. However the original value,
-- * rather than the result, is used to test for success in order to have
-- * better generated assembly.
-- */
--static inline void
--__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "ldrex %0, [%3] \n\t"
-- "add %1, %0, #1 \n\t"
-- "strex %2, %1, [%3] "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __orig |= __ex_flag;
-- if (unlikely(__orig != 0))
-- fail_fn(count);
--}
--
--/*
-- * If the unlock was done on a contended lock, or if the unlock simply fails
-- * then the mutex remains locked.
-- */
--#define __mutex_slowpath_needs_to_unlock() 1
--
--/*
-- * For __mutex_fastpath_trylock we use another construct which could be
-- * described as a "single value cmpxchg".
-- *
-- * This provides the needed trylock semantics like cmpxchg would, but it is
-- * lighter and less generic than a true cmpxchg implementation.
-- */
--static inline int
--__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "1: ldrex %0, [%3] \n\t"
-- "subs %1, %0, #1 \n\t"
-- "strexeq %2, %1, [%3] \n\t"
-- "movlt %0, #0 \n\t"
-- "cmpeq %2, #0 \n\t"
-- "bgt 1b "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&count->counter)
-- : "cc", "memory" );
--
-- return __orig;
--}
--
--#endif
-+#include <asm-generic/mutex-xchg.h>
- #endif
pcdp-use-early_ioremap-early_iounmap-to-access-pcdp-table.patch
mm-fix-wrong-argument-of-migrate_huge_pages-in-soft_offline_huge_page.patch
arm-7466-1-disable-interrupt-before-spinning-endlessly.patch
-arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
arm-7476-1-vfp-only-clear-vfp-state-for-current-cpu-in-vfp_pm_suspend.patch
arm-7477-1-vfp-always-save-vfp-state-in-vfp_pm_suspend-on-up.patch
arm-7478-1-errata-extend-workaround-for-erratum-720789.patch
+++ /dev/null
-From a76d7bd96d65fa5119adba97e1b58d95f2e78829 Mon Sep 17 00:00:00 2001
-From: Will Deacon <will.deacon@arm.com>
-Date: Fri, 13 Jul 2012 19:15:40 +0100
-Subject: ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+
-
-From: Will Deacon <will.deacon@arm.com>
-
-commit a76d7bd96d65fa5119adba97e1b58d95f2e78829 upstream.
-
-The open-coded mutex implementation for ARMv6+ cores suffers from a
-severe lack of barriers, so in the uncontended case we don't actually
-protect any accesses performed during the critical section.
-
-Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec
-code but optimised to remove a branch instruction, as the mutex fastpath
-was previously inlined. Now that this is executed out-of-line, we can
-reuse the atomic access code for the locking (in fact, we use the xchg
-code as this produces shorter critical sections).
-
-This patch uses the generic xchg based implementation for mutexes on
-ARMv6+, which introduces barriers to the lock/unlock operations and also
-has the benefit of removing a fair amount of inline assembly code.
-
-Acked-by: Arnd Bergmann <arnd@arndb.de>
-Acked-by: Nicolas Pitre <nico@linaro.org>
-Reported-by: Shan Kang <kangshan0910@gmail.com>
-Signed-off-by: Will Deacon <will.deacon@arm.com>
-Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- arch/arm/include/asm/mutex.h | 119 +------------------------------------------
- 1 file changed, 4 insertions(+), 115 deletions(-)
-
---- a/arch/arm/include/asm/mutex.h
-+++ b/arch/arm/include/asm/mutex.h
-@@ -7,121 +7,10 @@
- */
- #ifndef _ASM_MUTEX_H
- #define _ASM_MUTEX_H
--
--#if __LINUX_ARM_ARCH__ < 6
--/* On pre-ARMv6 hardware the swp based implementation is the most efficient. */
--# include <asm-generic/mutex-xchg.h>
--#else
--
- /*
-- * Attempting to lock a mutex on ARMv6+ can be done with a bastardized
-- * atomic decrement (it is not a reliable atomic decrement but it satisfies
-- * the defined semantics for our purpose, while being smaller and faster
-- * than a real atomic decrement or atomic swap. The idea is to attempt
-- * decrementing the lock value only once. If once decremented it isn't zero,
-- * or if its store-back fails due to a dispute on the exclusive store, we
-- * simply bail out immediately through the slow path where the lock will be
-- * reattempted until it succeeds.
-+ * On pre-ARMv6 hardware this results in a swp-based implementation,
-+ * which is the most efficient. For ARMv6+, we emit a pair of exclusive
-+ * accesses instead.
- */
--static inline void
--__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- fail_fn(count);
--}
--
--static inline int
--__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res;
--
-- __asm__ (
--
-- "ldrex %0, [%2] \n\t"
-- "sub %0, %0, #1 \n\t"
-- "strex %1, %0, [%2] "
--
-- : "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __res |= __ex_flag;
-- if (unlikely(__res != 0))
-- __res = fail_fn(count);
-- return __res;
--}
--
--/*
-- * Same trick is used for the unlock fast path. However the original value,
-- * rather than the result, is used to test for success in order to have
-- * better generated assembly.
-- */
--static inline void
--__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "ldrex %0, [%3] \n\t"
-- "add %1, %0, #1 \n\t"
-- "strex %2, %1, [%3] "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&(count)->counter)
-- : "cc","memory" );
--
-- __orig |= __ex_flag;
-- if (unlikely(__orig != 0))
-- fail_fn(count);
--}
--
--/*
-- * If the unlock was done on a contended lock, or if the unlock simply fails
-- * then the mutex remains locked.
-- */
--#define __mutex_slowpath_needs_to_unlock() 1
--
--/*
-- * For __mutex_fastpath_trylock we use another construct which could be
-- * described as a "single value cmpxchg".
-- *
-- * This provides the needed trylock semantics like cmpxchg would, but it is
-- * lighter and less generic than a true cmpxchg implementation.
-- */
--static inline int
--__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
--{
-- int __ex_flag, __res, __orig;
--
-- __asm__ (
--
-- "1: ldrex %0, [%3] \n\t"
-- "subs %1, %0, #1 \n\t"
-- "strexeq %2, %1, [%3] \n\t"
-- "movlt %0, #0 \n\t"
-- "cmpeq %2, #0 \n\t"
-- "bgt 1b "
--
-- : "=&r" (__orig), "=&r" (__res), "=&r" (__ex_flag)
-- : "r" (&count->counter)
-- : "cc", "memory" );
--
-- return __orig;
--}
--
--#endif
-+#include <asm-generic/mutex-xchg.h>
- #endif
memcg-further-prevent-oom-with-too-many-dirty-pages.patch
mm-fix-wrong-argument-of-migrate_huge_pages-in-soft_offline_huge_page.patch
arm-7466-1-disable-interrupt-before-spinning-endlessly.patch
-arm-7467-1-mutex-use-generic-xchg-based-implementation-for-armv6.patch
arm-7476-1-vfp-only-clear-vfp-state-for-current-cpu-in-vfp_pm_suspend.patch
arm-7477-1-vfp-always-save-vfp-state-in-vfp_pm_suspend-on-up.patch
arm-7478-1-errata-extend-workaround-for-erratum-720789.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
