diff options
| author | Will Deacon <will.deacon@arm.com> | 2017-10-24 13:22:48 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-17 15:57:15 +0300 |
| commit | 3382290ed2d5e275429cef510ab21889d3ccd164 (patch) | |
| tree | 0993c387956cf3b6f802acf12a62b79cb94ece1a /arch | |
| parent | c2bc66082e1048c7573d72e62f597bdc5ce13fea (diff) | |
| download | linux-3382290ed2d5e275429cef510ab21889d3ccd164.tar.xz | |
locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
[ Note, this is a Git cherry-pick of the following commit:
506458efaf15 ("locking/barriers: Convert users of lockless_dereference() to READ_ONCE()")
... for easier x86 PTI code testing and back-porting. ]
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/events/core.c | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/mmu_context.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/ldt.c | 2 |
3 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 80534d3c2480..589af1eec7c1 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2371,7 +2371,7 @@ static unsigned long get_segment_base(unsigned int segment) struct ldt_struct *ldt; /* IRQs are off, so this synchronizes with smp_store_release */ - ldt = lockless_dereference(current->active_mm->context.ldt); + ldt = READ_ONCE(current->active_mm->context.ldt); if (!ldt || idx >= ldt->nr_entries) return 0; diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 6699fc441644..6d16d15d09a0 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -73,8 +73,8 @@ static inline void load_mm_ldt(struct mm_struct *mm) #ifdef CONFIG_MODIFY_LDT_SYSCALL struct ldt_struct *ldt; - /* lockless_dereference synchronizes with smp_store_release */ - ldt = lockless_dereference(mm->context.ldt); + /* READ_ONCE synchronizes with smp_store_release */ + ldt = READ_ONCE(mm->context.ldt); /* * Any change to mm->context.ldt is followed by an IPI to all diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index ae5615b03def..1c1eae961340 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -103,7 +103,7 @@ static void finalize_ldt_struct(struct ldt_struct *ldt) static void install_ldt(struct mm_struct *current_mm, struct ldt_struct *ldt) { - /* Synchronizes with lockless_dereference in load_mm_ldt. */ + /* Synchronizes with READ_ONCE in load_mm_ldt. */ smp_store_release(¤t_mm->context.ldt, ldt); /* Activate the LDT for all CPUs using current_mm. */ |