# check for 'asm goto'
ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+ KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
endif
include $(srctree)/scripts/Makefile.kasan
#ifndef _ASM_ARM_JUMP_LABEL_H
#define _ASM_ARM_JUMP_LABEL_H
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
#include <linux/types.h>
return true;
}
-#endif /* __KERNEL__ */
-
typedef u32 jump_label_t;
struct jump_entry {
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif
*/
#ifndef __ASM_JUMP_LABEL_H
#define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#include <asm/insn.h>
-#ifdef __KERNEL__
-
#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE
static __always_inline bool arch_static_branch(struct static_key *key)
return true;
}
-#endif /* __KERNEL__ */
-
typedef u64 jump_label_t;
struct jump_entry {
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif /* __ASM_JUMP_LABEL_H */
#ifndef _ASM_MIPS_JUMP_LABEL_H
#define _ASM_MIPS_JUMP_LABEL_H
-#include <linux/types.h>
+#ifndef __ASSEMBLY__
-#ifdef __KERNEL__
+#include <linux/types.h>
#define JUMP_LABEL_NOP_SIZE 4
return true;
}
-#endif /* __KERNEL__ */
-
#ifdef CONFIG_64BIT
typedef u64 jump_label_t;
#else
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_MIPS_JUMP_LABEL_H */
* 2 of the License, or (at your option) any later version.
*/
+#include <linux/jump_label.h>
#include <asm/ppc_asm.h>
#include <asm/hvcall.h>
#include <asm/asm-offsets.h>
#include <asm/opal.h>
-#include <asm/jump_label.h>
.section ".text"
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
+#include <linux/jump_label.h>
#include <asm/hvcall.h>
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ptrace.h>
-#include <asm/jump_label.h>
.section ".text"
#include <linux/dma-mapping.h>
#include <linux/console.h>
#include <linux/export.h>
-#include <linux/static_key.h>
+#include <linux/jump_label.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/page.h>
#ifndef _ASM_S390_JUMP_LABEL_H
#define _ASM_S390_JUMP_LABEL_H
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#define JUMP_LABEL_NOP_SIZE 6
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif
#ifndef _ASM_SPARC_JUMP_LABEL_H
#define _ASM_SPARC_JUMP_LABEL_H
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
#include <linux/types.h>
return true;
}
-#endif /* __KERNEL__ */
-
typedef u32 jump_label_t;
struct jump_entry {
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif
#ifndef _ASM_X86_JUMP_LABEL_H
#define _ASM_X86_JUMP_LABEL_H
-#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
#include <linux/stringify.h>
#include <linux/types.h>
return true;
}
-#endif /* __KERNEL__ */
-
#ifdef CONFIG_X86_64
typedef u64 jump_label_t;
#else
jump_label_t key;
};
+#endif /* __ASSEMBLY__ */
#endif
#include <uapi/linux/types.h>
-static __always_inline void data_access_exceeds_word_size(void)
-#ifdef __compiletime_warning
-__compiletime_warning("data access exceeds word size and won't be atomic")
-#endif
-;
-
-static __always_inline void data_access_exceeds_word_size(void)
-{
-}
-
static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
{
switch (size) {
case 1: *(__u8 *)res = *(volatile __u8 *)p; break;
case 2: *(__u16 *)res = *(volatile __u16 *)p; break;
case 4: *(__u32 *)res = *(volatile __u32 *)p; break;
-#ifdef CONFIG_64BIT
case 8: *(__u64 *)res = *(volatile __u64 *)p; break;
-#endif
default:
barrier();
__builtin_memcpy((void *)res, (const void *)p, size);
- data_access_exceeds_word_size();
barrier();
}
}
case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
-#ifdef CONFIG_64BIT
case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
-#endif
default:
barrier();
__builtin_memcpy((void *)p, (const void *)res, size);
- data_access_exceeds_word_size();
barrier();
}
}
* same as using STATIC_KEY_INIT_FALSE.
*/
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+# define HAVE_JUMP_LABEL
+#endif
+
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/bug.h>
"%s used before call to jump_label_init", \
__func__)
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#ifdef HAVE_JUMP_LABEL
struct static_key {
atomic_t enabled;
#endif
};
-# include <asm/jump_label.h>
-# define HAVE_JUMP_LABEL
#else
struct static_key {
atomic_t enabled;
};
-#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
+#endif /* HAVE_JUMP_LABEL */
+#endif /* __ASSEMBLY__ */
+
+#ifdef HAVE_JUMP_LABEL
+#include <asm/jump_label.h>
+#endif
+
+#ifndef __ASSEMBLY__
enum jump_label_type {
JUMP_LABEL_DISABLE = 0,
}
#endif /* _LINUX_JUMP_LABEL_H */
+
+#endif /* __ASSEMBLY__ */
unsigned ret;
repeat:
- ret = ACCESS_ONCE(s->sequence);
+ ret = READ_ONCE(s->sequence);
if (unlikely(ret & 1)) {
cpu_relax();
goto repeat;
*/
static inline unsigned raw_read_seqcount(const seqcount_t *s)
{
- unsigned ret = ACCESS_ONCE(s->sequence);
+ unsigned ret = READ_ONCE(s->sequence);
smp_rmb();
return ret;
}
*/
static inline unsigned raw_seqcount_begin(const seqcount_t *s)
{
- unsigned ret = ACCESS_ONCE(s->sequence);
+ unsigned ret = READ_ONCE(s->sequence);
smp_rmb();
return ret & ~1;
}
if (!p)
return -ESRCH;
- if (!p->mm) {
+ if (unlikely(p->flags & PF_KTHREAD)) {
put_task_struct(p);
return -EPERM;
}
*/
return;
}
- ACCESS_ONCE(prev->next) = node;
+ WRITE_ONCE(prev->next, node);
/* Wait until the lock holder passes the lock down. */
arch_mcs_spin_lock_contended(&node->locked);
static inline
void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
{
- struct mcs_spinlock *next = ACCESS_ONCE(node->next);
+ struct mcs_spinlock *next = READ_ONCE(node->next);
if (likely(!next)) {
/*
if (likely(cmpxchg(lock, node, NULL) == node))
return;
/* Wait until the next pointer is set */
- while (!(next = ACCESS_ONCE(node->next)))
+ while (!(next = READ_ONCE(node->next)))
cpu_relax_lowlatency();
}
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
-#include "mcs_spinlock.h"
+#include <linux/osq_lock.h>
/*
* In the DEBUG case we are using the "NULL fastpath" for mutexes,
}
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
-{
- if (lock->owner != owner)
- return false;
-
- /*
- * Ensure we emit the owner->on_cpu, dereference _after_ checking
- * lock->owner still matches owner, if that fails, owner might
- * point to free()d memory, if it still matches, the rcu_read_lock()
- * ensures the memory stays valid.
- */
- barrier();
-
- return owner->on_cpu;
-}
-
/*
* Look out! "owner" is an entirely speculative pointer
* access and not reliable.
*/
static noinline
-int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
+bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
{
+ bool ret = true;
+
rcu_read_lock();
- while (owner_running(lock, owner)) {
- if (need_resched())
+ while (lock->owner == owner) {
+ /*
+ * Ensure we emit the owner->on_cpu, dereference _after_
+ * checking lock->owner still matches owner. If that fails,
+ * owner might point to freed memory. If it still matches,
+ * the rcu_read_lock() ensures the memory stays valid.
+ */
+ barrier();
+
+ if (!owner->on_cpu || need_resched()) {
+ ret = false;
break;
+ }
cpu_relax_lowlatency();
}
rcu_read_unlock();
- /*
- * We break out the loop above on need_resched() and when the
- * owner changed, which is a sign for heavy contention. Return
- * success only when lock->owner is NULL.
- */
- return lock->owner == NULL;
+ return ret;
}
/*
return 0;
rcu_read_lock();
- owner = ACCESS_ONCE(lock->owner);
+ owner = READ_ONCE(lock->owner);
if (owner)
retval = owner->on_cpu;
rcu_read_unlock();
* As such, when deadlock detection needs to be
* performed the optimistic spinning cannot be done.
*/
- if (ACCESS_ONCE(ww->ctx))
+ if (READ_ONCE(ww->ctx))
break;
}
* If there's an owner, wait for it to either
* release the lock or go to sleep.
*/
- owner = ACCESS_ONCE(lock->owner);
+ owner = READ_ONCE(lock->owner);
if (owner && !mutex_spin_on_owner(lock, owner))
break;
__ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx)
{
struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
+ struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
if (!hold_ctx)
return 0;
prev = decode_cpu(old);
node->prev = prev;
- ACCESS_ONCE(prev->next) = node;
+ WRITE_ONCE(prev->next, node);
/*
* Normally @prev is untouchable after the above store; because at that
* cmpxchg in an attempt to undo our queueing.
*/
- while (!ACCESS_ONCE(node->locked)) {
+ while (!READ_ONCE(node->locked)) {
/*
* If we need to reschedule bail... so we can block.
*/
* Or we race against a concurrent unqueue()'s step-B, in which
* case its step-C will write us a new @node->prev pointer.
*/
- prev = ACCESS_ONCE(node->prev);
+ prev = READ_ONCE(node->prev);
}
/*
* it will wait in Step-A.
*/
- ACCESS_ONCE(next->prev) = prev;
- ACCESS_ONCE(prev->next) = next;
+ WRITE_ONCE(next->prev, prev);
+ WRITE_ONCE(prev->next, next);
return false;
}
node = this_cpu_ptr(&osq_node);
next = xchg(&node->next, NULL);
if (next) {
- ACCESS_ONCE(next->locked) = 1;
+ WRITE_ONCE(next->locked, 1);
return;
}
next = osq_wait_next(lock, node, NULL);
if (next)
- ACCESS_ONCE(next->locked) = 1;
+ WRITE_ONCE(next->locked, 1);
}
*
* @task: the task owning the mutex (owner) for which a chain walk is
* probably needed
- * @deadlock_detect: do we have to carry out deadlock detection?
+ * @chwalk: do we have to carry out deadlock detection?
* @orig_lock: the mutex (can be NULL if we are walking the chain to recheck
* things for a task that has just got its priority adjusted, and
* is waiting on a mutex)
list_del(&waiter->list);
tsk = waiter->task;
+ /*
+ * Make sure we do not wakeup the next reader before
+ * setting the nil condition to grant the next reader;
+ * otherwise we could miss the wakeup on the other
+ * side and end up sleeping again. See the pairing
+ * in rwsem_down_read_failed().
+ */
smp_mb();
waiter->task = NULL;
wake_up_process(tsk);
#include <linux/init.h>
#include <linux/export.h>
#include <linux/sched/rt.h>
+#include <linux/osq_lock.h>
-#include "mcs_spinlock.h"
+#include "rwsem.h"
/*
* Guide to the rw_semaphore's count field for common values.
waiter = list_entry(next, struct rwsem_waiter, list);
next = waiter->list.next;
tsk = waiter->task;
+ /*
+ * Make sure we do not wakeup the next reader before
+ * setting the nil condition to grant the next reader;
+ * otherwise we could miss the wakeup on the other
+ * side and end up sleeping again. See the pairing
+ * in rwsem_down_read_failed().
+ */
smp_mb();
waiter->task = NULL;
wake_up_process(tsk);
RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
if (!list_is_singular(&sem->wait_list))
rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
+ rwsem_set_owner(sem);
return true;
}
*/
static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
{
- long old, count = ACCESS_ONCE(sem->count);
+ long old, count = READ_ONCE(sem->count);
while (true) {
if (!(count == 0 || count == RWSEM_WAITING_BIAS))
return false;
old = cmpxchg(&sem->count, count, count + RWSEM_ACTIVE_WRITE_BIAS);
- if (old == count)
+ if (old == count) {
+ rwsem_set_owner(sem);
return true;
+ }
count = old;
}
static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
{
struct task_struct *owner;
- bool on_cpu = false;
+ bool ret = true;
if (need_resched())
return false;
rcu_read_lock();
- owner = ACCESS_ONCE(sem->owner);
- if (owner)
- on_cpu = owner->on_cpu;
- rcu_read_unlock();
-
- /*
- * If sem->owner is not set, yet we have just recently entered the
- * slowpath, then there is a possibility reader(s) may have the lock.
- * To be safe, avoid spinning in these situations.
- */
- return on_cpu;
-}
-
-static inline bool owner_running(struct rw_semaphore *sem,
- struct task_struct *owner)
-{
- if (sem->owner != owner)
- return false;
-
- /*
- * Ensure we emit the owner->on_cpu, dereference _after_ checking
- * sem->owner still matches owner, if that fails, owner might
- * point to free()d memory, if it still matches, the rcu_read_lock()
- * ensures the memory stays valid.
- */
- barrier();
+ owner = READ_ONCE(sem->owner);
+ if (!owner) {
+ long count = READ_ONCE(sem->count);
+ /*
+ * If sem->owner is not set, yet we have just recently entered the
+ * slowpath with the lock being active, then there is a possibility
+ * reader(s) may have the lock. To be safe, bail spinning in these
+ * situations.
+ */
+ if (count & RWSEM_ACTIVE_MASK)
+ ret = false;
+ goto done;
+ }
- return owner->on_cpu;
+ ret = owner->on_cpu;
+done:
+ rcu_read_unlock();
+ return ret;
}
static noinline
bool rwsem_spin_on_owner(struct rw_semaphore *sem, struct task_struct *owner)
{
+ long count;
+
rcu_read_lock();
- while (owner_running(sem, owner)) {
- if (need_resched())
- break;
+ while (sem->owner == owner) {
+ /*
+ * Ensure we emit the owner->on_cpu, dereference _after_
+ * checking sem->owner still matches owner, if that fails,
+ * owner might point to free()d memory, if it still matches,
+ * the rcu_read_lock() ensures the memory stays valid.
+ */
+ barrier();
+
+ /* abort spinning when need_resched or owner is not running */
+ if (!owner->on_cpu || need_resched()) {
+ rcu_read_unlock();
+ return false;
+ }
cpu_relax_lowlatency();
}
rcu_read_unlock();
+ if (READ_ONCE(sem->owner))
+ return true; /* new owner, continue spinning */
+
/*
- * We break out the loop above on need_resched() or when the
- * owner changed, which is a sign for heavy contention. Return
- * success only when sem->owner is NULL.
+ * When the owner is not set, the lock could be free or
+ * held by readers. Check the counter to verify the
+ * state.
*/
- return sem->owner == NULL;
+ count = READ_ONCE(sem->count);
+ return (count == 0 || count == RWSEM_WAITING_BIAS);
}
static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
goto done;
while (true) {
- owner = ACCESS_ONCE(sem->owner);
+ owner = READ_ONCE(sem->owner);
if (owner && !rwsem_spin_on_owner(sem, owner))
break;
/* we're now waiting on the lock, but no longer actively locking */
if (waiting) {
- count = ACCESS_ONCE(sem->count);
+ count = READ_ONCE(sem->count);
/*
* If there were already threads queued before us and there are
#include <linux/sched.h>
#include <linux/export.h>
#include <linux/rwsem.h>
-
#include <linux/atomic.h>
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-static inline void rwsem_set_owner(struct rw_semaphore *sem)
-{
- sem->owner = current;
-}
-
-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
-{
- sem->owner = NULL;
-}
-
-#else
-static inline void rwsem_set_owner(struct rw_semaphore *sem)
-{
-}
-
-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
-{
-}
-#endif
+#include "rwsem.h"
/*
* lock for reading
--- /dev/null
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+ sem->owner = current;
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+ sem->owner = NULL;
+}
+
+#else
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+}
+#endif
#define CMPXCHG_LOOP(CODE, SUCCESS) do { \
struct lockref old; \
BUILD_BUG_ON(sizeof(old) != 8); \
- old.lock_count = ACCESS_ONCE(lockref->lock_count); \
+ old.lock_count = READ_ONCE(lockref->lock_count); \
while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \
struct lockref new = old, prev = old; \
CODE \
projects / mirror_ubuntu-artful-kernel.git / commitdiff