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Message-ID: <20191001215249.4157062-15-paul.burton@mips.com>
Date: Tue, 1 Oct 2019 21:53:23 +0000
From: Paul Burton <paul.burton@...s.com>
To: "linux-mips@...r.kernel.org" <linux-mips@...r.kernel.org>
CC: Huacai Chen <chenhc@...ote.com>,
Jiaxun Yang <jiaxun.yang@...goat.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Paul Burton <pburton@...ecomp.com>
Subject: [PATCH v2 14/36] MIPS: atomic: Unify 32b & 64b sub_if_positive
Unify the definitions of atomic_sub_if_positive() &
atomic64_sub_if_positive() using a macro like we do for most other
atomic functions. This allows us to share the implementation ensuring
consistency between the two. Notably this provides the appropriate
loongson3_war barriers in the atomic64_sub_if_positive() case which were
previously missing.
The code is rearranged a little to handle the !kernel_uses_llsc case
first in order to de-indent the LL/SC case & allow us not to go over 80
characters per line.
Signed-off-by: Paul Burton <paul.burton@...s.com>
---
Changes in v2: None
arch/mips/include/asm/atomic.h | 164 ++++++++++++---------------------
1 file changed, 58 insertions(+), 106 deletions(-)
diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 24443ef29337..96ef50fa2817 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -192,65 +192,71 @@ ATOMIC_OPS(atomic64, xor, s64, ^=, xor, lld, scd)
* Atomically test @v and subtract @i if @v is greater or equal than @i.
* The function returns the old value of @v minus @i.
*/
-static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
-{
- int result;
-
- smp_mb__before_atomic();
-
- if (kernel_uses_llsc) {
- int temp;
-
- __asm__ __volatile__(
- " .set push \n"
- " .set "MIPS_ISA_LEVEL" \n"
- " " __SYNC(full, loongson3_war) " \n"
- "1: ll %1, %2 # atomic_sub_if_positive\n"
- " .set pop \n"
- " subu %0, %1, %3 \n"
- " move %1, %0 \n"
- " bltz %0, 2f \n"
- " .set push \n"
- " .set "MIPS_ISA_LEVEL" \n"
- " sc %1, %2 \n"
- "\t" __SC_BEQZ "%1, 1b \n"
- "2: " __SYNC(full, loongson3_war) " \n"
- " .set pop \n"
- : "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
- : "Ir" (i) : __LLSC_CLOBBER);
- } else {
- unsigned long flags;
+#define ATOMIC_SIP_OP(pfx, type, op, ll, sc) \
+static __inline__ int pfx##_sub_if_positive(type i, pfx##_t * v) \
+{ \
+ type temp, result; \
+ \
+ smp_mb__before_atomic(); \
+ \
+ if (!kernel_uses_llsc) { \
+ unsigned long flags; \
+ \
+ raw_local_irq_save(flags); \
+ result = v->counter; \
+ result -= i; \
+ if (result >= 0) \
+ v->counter = result; \
+ raw_local_irq_restore(flags); \
+ smp_mb__after_atomic(); \
+ return result; \
+ } \
+ \
+ __asm__ __volatile__( \
+ " .set push \n" \
+ " .set " MIPS_ISA_LEVEL " \n" \
+ " " __SYNC(full, loongson3_war) " \n" \
+ "1: " #ll " %1, %2 # atomic_sub_if_positive\n" \
+ " .set pop \n" \
+ " " #op " %0, %1, %3 \n" \
+ " move %1, %0 \n" \
+ " bltz %0, 2f \n" \
+ " .set push \n" \
+ " .set " MIPS_ISA_LEVEL " \n" \
+ " " #sc " %1, %2 \n" \
+ " " __SC_BEQZ "%1, 1b \n" \
+ "2: " __SYNC(full, loongson3_war) " \n" \
+ " .set pop \n" \
+ : "=&r" (result), "=&r" (temp), \
+ "+" GCC_OFF_SMALL_ASM() (v->counter) \
+ : "Ir" (i) \
+ : __LLSC_CLOBBER); \
+ \
+ /* \
+ * In the Loongson3 workaround case we already have a \
+ * completion barrier at 2: above, which is needed due to the \
+ * bltz that can branch to code outside of the LL/SC loop. As \
+ * such, we don't need to emit another barrier here. \
+ */ \
+ if (!__SYNC_loongson3_war) \
+ smp_mb__after_atomic(); \
+ \
+ return result; \
+}
- raw_local_irq_save(flags);
- result = v->counter;
- result -= i;
- if (result >= 0)
- v->counter = result;
- raw_local_irq_restore(flags);
- }
+ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
+#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
- /*
- * In the Loongson3 workaround case we already have a completion
- * barrier at 2: above, which is needed due to the bltz that can branch
- * to code outside of the LL/SC loop. As such, we don't need to emit
- * another barrier here.
- */
- if (!__SYNC_loongson3_war)
- smp_mb__after_atomic();
+#ifdef CONFIG_64BIT
+ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
+#define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
+#endif
- return result;
-}
+#undef ATOMIC_SIP_OP
#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
-/*
- * atomic_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic_t
- */
-#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
-
#ifdef CONFIG_64BIT
#define ATOMIC64_INIT(i) { (i) }
@@ -269,64 +275,10 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
*/
#define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))
-/*
- * atomic64_sub_if_positive - conditionally subtract integer from atomic
- * variable
- * @i: integer value to subtract
- * @v: pointer of type atomic64_t
- *
- * Atomically test @v and subtract @i if @v is greater or equal than @i.
- * The function returns the old value of @v minus @i.
- */
-static __inline__ s64 atomic64_sub_if_positive(s64 i, atomic64_t * v)
-{
- s64 result;
-
- smp_mb__before_llsc();
-
- if (kernel_uses_llsc) {
- s64 temp;
-
- __asm__ __volatile__(
- " .set push \n"
- " .set "MIPS_ISA_LEVEL" \n"
- "1: lld %1, %2 # atomic64_sub_if_positive\n"
- " dsubu %0, %1, %3 \n"
- " move %1, %0 \n"
- " bltz %0, 1f \n"
- " scd %1, %2 \n"
- "\t" __SC_BEQZ "%1, 1b \n"
- "1: \n"
- " .set pop \n"
- : "=&r" (result), "=&r" (temp),
- "+" GCC_OFF_SMALL_ASM() (v->counter)
- : "Ir" (i));
- } else {
- unsigned long flags;
-
- raw_local_irq_save(flags);
- result = v->counter;
- result -= i;
- if (result >= 0)
- v->counter = result;
- raw_local_irq_restore(flags);
- }
-
- smp_llsc_mb();
-
- return result;
-}
-
#define atomic64_cmpxchg(v, o, n) \
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))
-/*
- * atomic64_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic64_t
- */
-#define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
-
#endif /* CONFIG_64BIT */
#endif /* _ASM_ATOMIC_H */
--
2.23.0
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