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Message-Id: <20200630173734.14057-8-will@kernel.org>
Date: Tue, 30 Jun 2020 18:37:23 +0100
From: Will Deacon <will@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Will Deacon <will@...nel.org>,
Sami Tolvanen <samitolvanen@...gle.com>,
Nick Desaulniers <ndesaulniers@...gle.com>,
Kees Cook <keescook@...omium.org>,
Marco Elver <elver@...gle.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 S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
Boqun Feng <boqun.feng@...il.com>,
Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>,
linux-arm-kernel@...ts.infradead.org, linux-alpha@...r.kernel.org,
virtualization@...ts.linux-foundation.org, kernel-team@...roid.com
Subject: [PATCH 07/18] 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.
Acked-by: Paul E. McKenney <paulmck@...nel.org>
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 162c17b2631f..660b14ce1317 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -277,9 +277,9 @@ extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; retur
extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
/*
- * 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
@@ -293,7 +293,7 @@ extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; retu
extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address)
{
pmd_t *ret = (pmd_t *) pud_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
- smp_read_barrier_depends(); /* see above */
+ smp_rmb(); /* see above */
return ret;
}
#define pmd_offset pmd_offset
@@ -303,7 +303,7 @@ 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;
}
#define pte_offset_kernel pte_offset_kernel
diff --git a/mm/memory.c b/mm/memory.c
index 87ec87cdc1ff..e1f2c730d8bb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -437,7 +437,7 @@ 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 */
--
2.27.0.212.ge8ba1cc988-goog
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