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Date: Fri, 8 Nov 2019 17:01:14 +0000
From: Will Deacon <will@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Will Deacon <will@...nel.org>, Yunjae Lee <lyj7694@...il.com>,
SeongJae Park <sj38.park@...il.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Josh Triplett <josh@...htriplett.org>,
Matt Turner <mattst88@...il.com>,
Ivan Kokshaysky <ink@...assic.park.msu.ru>,
Richard Henderson <rth@...ddle.net>,
Peter Zijlstra <peterz@...radead.org>,
Alan Stern <stern@...land.harvard.edu>,
Michael Ellerman <mpe@...erman.id.au>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
Arnd Bergmann <arnd@...db.de>, Joe Perches <joe@...ches.com>,
Boqun Feng <boqun.feng@...il.com>, linux-alpha@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: [PATCH 07/13] alpha: Replace smp_read_barrier_depends() usage with smp_[r]mb()
In preparation for removing 'smp_read_barrier_depends()' altogether,
move the Alpha code over to using 'smp_rmb()' and 'smp_mb()' directly.
Signed-off-by: Will Deacon <will@...nel.org>
---
arch/alpha/include/asm/atomic.h | 16 ++++++++--------
arch/alpha/include/asm/pgtable.h | 10 +++++-----
mm/memory.c | 2 +-
3 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h
index 2144530d1428..2f8f7e54792f 100644
--- a/arch/alpha/include/asm/atomic.h
+++ b/arch/alpha/include/asm/atomic.h
@@ -16,10 +16,10 @@
/*
* To ensure dependency ordering is preserved for the _relaxed and
- * _release atomics, an smp_read_barrier_depends() is unconditionally
- * inserted into the _relaxed variants, which are used to build the
- * barriered versions. Avoid redundant back-to-back fences in the
- * _acquire and _fence versions.
+ * _release atomics, an smp_mb() is unconditionally inserted into the
+ * _relaxed variants, which are used to build the barriered versions.
+ * Avoid redundant back-to-back fences in the _acquire and _fence
+ * versions.
*/
#define __atomic_acquire_fence()
#define __atomic_post_full_fence()
@@ -70,7 +70,7 @@ static inline int atomic_##op##_return_relaxed(int i, atomic_t *v) \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
- smp_read_barrier_depends(); \
+ smp_mb(); \
return result; \
}
@@ -88,7 +88,7 @@ static inline int atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
- smp_read_barrier_depends(); \
+ smp_mb(); \
return result; \
}
@@ -123,7 +123,7 @@ static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
- smp_read_barrier_depends(); \
+ smp_mb(); \
return result; \
}
@@ -141,7 +141,7 @@ static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
- smp_read_barrier_depends(); \
+ smp_mb(); \
return result; \
}
diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 065b57f408c3..b807793646c7 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -288,9 +288,9 @@ extern inline pte_t pte_mkspecial(pte_t pte) { return pte; }
#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
/*
- * The smp_read_barrier_depends() in the following functions are required to
- * order the load of *dir (the pointer in the top level page table) with any
- * subsequent load of the returned pmd_t *ret (ret is data dependent on *dir).
+ * The smp_rmb() in the following functions are required to order the load of
+ * *dir (the pointer in the top level page table) with any subsequent load of
+ * the returned pmd_t *ret (ret is data dependent on *dir).
*
* If this ordering is not enforced, the CPU might load an older value of
* *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for
@@ -304,7 +304,7 @@ extern inline pte_t pte_mkspecial(pte_t pte) { return pte; }
extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
{
pmd_t *ret = (pmd_t *) pgd_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
- smp_read_barrier_depends(); /* see above */
+ smp_rmb(); /* see above */
return ret;
}
@@ -313,7 +313,7 @@ extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
{
pte_t *ret = (pte_t *) pmd_page_vaddr(*dir)
+ ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
- smp_read_barrier_depends(); /* see above */
+ smp_rmb(); /* see above */
return ret;
}
diff --git a/mm/memory.c b/mm/memory.c
index b1ca51a079f2..c4a74e6d2c5c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -420,7 +420,7 @@ int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
* of a chain of data-dependent loads, meaning most CPUs (alpha
* being the notable exception) will already guarantee loads are
* seen in-order. See the alpha page table accessors for the
- * smp_read_barrier_depends() barriers in page table walking code.
+ * smp_rmb() barriers in page table walking code.
*/
smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
--
2.24.0.rc1.363.gb1bccd3e3d-goog
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