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Message-Id: <20210804191554.1252776-2-vgupta@synopsys.com>
Date: Wed, 4 Aug 2021 12:15:44 -0700
From: Vineet Gupta <Vineet.Gupta1@...opsys.com>
To: linux-snps-arc@...ts.infradead.org
Cc: Peter Zijlstra <peterz@...radead.org>,
Will Deacon <will@...nel.org>, Arnd Bergmann <arnd@...db.de>,
Mark Rutland <mark.rutland@....com>,
linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
Vladimir Isaev <Vladimir.Isaev@...opsys.com>,
Vineet Gupta <Vineet.Gupta1@...opsys.com>
Subject: [PATCH 01/11] ARC: atomics: disintegrate header
Non functional change, to ease future addition/removal
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
---
arch/arc/include/asm/atomic-llsc.h | 103 ++++++
arch/arc/include/asm/atomic-spinlock.h | 111 +++++++
arch/arc/include/asm/atomic.h | 429 +------------------------
arch/arc/include/asm/atomic64-arcv2.h | 242 ++++++++++++++
4 files changed, 461 insertions(+), 424 deletions(-)
create mode 100644 arch/arc/include/asm/atomic-llsc.h
create mode 100644 arch/arc/include/asm/atomic-spinlock.h
create mode 100644 arch/arc/include/asm/atomic64-arcv2.h
diff --git a/arch/arc/include/asm/atomic-llsc.h b/arch/arc/include/asm/atomic-llsc.h
new file mode 100644
index 000000000000..aab4f2855457
--- /dev/null
+++ b/arch/arc/include/asm/atomic-llsc.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_ARC_ATOMIC_LLSC_H
+#define _ASM_ARC_ATOMIC_LLSC_H
+
+#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
+
+#define ATOMIC_OP(op, c_op, asm_op) \
+static inline void arch_atomic_##op(int i, atomic_t *v) \
+{ \
+ unsigned int val; \
+ \
+ __asm__ __volatile__( \
+ "1: llock %[val], [%[ctr]] \n" \
+ " " #asm_op " %[val], %[val], %[i] \n" \
+ " scond %[val], [%[ctr]] \n" \
+ " bnz 1b \n" \
+ : [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \
+ : [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \
+ [i] "ir" (i) \
+ : "cc"); \
+} \
+
+#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
+static inline int arch_atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ unsigned int val; \
+ \
+ /* \
+ * Explicit full memory barrier needed before/after as \
+ * LLOCK/SCOND themselves don't provide any such semantics \
+ */ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ "1: llock %[val], [%[ctr]] \n" \
+ " " #asm_op " %[val], %[val], %[i] \n" \
+ " scond %[val], [%[ctr]] \n" \
+ " bnz 1b \n" \
+ : [val] "=&r" (val) \
+ : [ctr] "r" (&v->counter), \
+ [i] "ir" (i) \
+ : "cc"); \
+ \
+ smp_mb(); \
+ \
+ return val; \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
+static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
+{ \
+ unsigned int val, orig; \
+ \
+ /* \
+ * Explicit full memory barrier needed before/after as \
+ * LLOCK/SCOND themselves don't provide any such semantics \
+ */ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ "1: llock %[orig], [%[ctr]] \n" \
+ " " #asm_op " %[val], %[orig], %[i] \n" \
+ " scond %[val], [%[ctr]] \n" \
+ " bnz 1b \n" \
+ : [val] "=&r" (val), \
+ [orig] "=&r" (orig) \
+ : [ctr] "r" (&v->counter), \
+ [i] "ir" (i) \
+ : "cc"); \
+ \
+ smp_mb(); \
+ \
+ return orig; \
+}
+
+#define ATOMIC_OPS(op, c_op, asm_op) \
+ ATOMIC_OP(op, c_op, asm_op) \
+ ATOMIC_OP_RETURN(op, c_op, asm_op) \
+ ATOMIC_FETCH_OP(op, c_op, asm_op)
+
+ATOMIC_OPS(add, +=, add)
+ATOMIC_OPS(sub, -=, sub)
+
+#undef ATOMIC_OPS
+#define ATOMIC_OPS(op, c_op, asm_op) \
+ ATOMIC_OP(op, c_op, asm_op) \
+ ATOMIC_FETCH_OP(op, c_op, asm_op)
+
+ATOMIC_OPS(and, &=, and)
+ATOMIC_OPS(andnot, &= ~, bic)
+ATOMIC_OPS(or, |=, or)
+ATOMIC_OPS(xor, ^=, xor)
+
+#define arch_atomic_andnot arch_atomic_andnot
+#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
+
+#endif
diff --git a/arch/arc/include/asm/atomic-spinlock.h b/arch/arc/include/asm/atomic-spinlock.h
new file mode 100644
index 000000000000..bdf87610b2d7
--- /dev/null
+++ b/arch/arc/include/asm/atomic-spinlock.h
@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_ARC_ATOMIC_SPLOCK_H
+#define _ASM_ARC_ATOMIC_SPLOCK_H
+
+#ifndef CONFIG_SMP
+
+ /* violating atomic_xxx API locking protocol in UP for optimization sake */
+#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
+
+#else
+
+static inline void arch_atomic_set(atomic_t *v, int i)
+{
+ /*
+ * Independent of hardware support, all of the atomic_xxx() APIs need
+ * to follow the same locking rules to make sure that a "hardware"
+ * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
+ * sequence
+ *
+ * Thus atomic_set() despite being 1 insn (and seemingly atomic)
+ * requires the locking.
+ */
+ unsigned long flags;
+
+ atomic_ops_lock(flags);
+ WRITE_ONCE(v->counter, i);
+ atomic_ops_unlock(flags);
+}
+
+#define arch_atomic_set_release(v, i) arch_atomic_set((v), (i))
+
+#endif
+
+/*
+ * Non hardware assisted Atomic-R-M-W
+ * Locking would change to irq-disabling only (UP) and spinlocks (SMP)
+ */
+
+#define ATOMIC_OP(op, c_op, asm_op) \
+static inline void arch_atomic_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ \
+ atomic_ops_lock(flags); \
+ v->counter c_op i; \
+ atomic_ops_unlock(flags); \
+}
+
+#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
+static inline int arch_atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ unsigned long temp; \
+ \
+ /* \
+ * spin lock/unlock provides the needed smp_mb() before/after \
+ */ \
+ atomic_ops_lock(flags); \
+ temp = v->counter; \
+ temp c_op i; \
+ v->counter = temp; \
+ atomic_ops_unlock(flags); \
+ \
+ return temp; \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
+static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ unsigned long orig; \
+ \
+ /* \
+ * spin lock/unlock provides the needed smp_mb() before/after \
+ */ \
+ atomic_ops_lock(flags); \
+ orig = v->counter; \
+ v->counter c_op i; \
+ atomic_ops_unlock(flags); \
+ \
+ return orig; \
+}
+
+#define ATOMIC_OPS(op, c_op, asm_op) \
+ ATOMIC_OP(op, c_op, asm_op) \
+ ATOMIC_OP_RETURN(op, c_op, asm_op) \
+ ATOMIC_FETCH_OP(op, c_op, asm_op)
+
+ATOMIC_OPS(add, +=, add)
+ATOMIC_OPS(sub, -=, sub)
+
+#undef ATOMIC_OPS
+#define ATOMIC_OPS(op, c_op, asm_op) \
+ ATOMIC_OP(op, c_op, asm_op) \
+ ATOMIC_FETCH_OP(op, c_op, asm_op)
+
+ATOMIC_OPS(and, &=, and)
+ATOMIC_OPS(andnot, &= ~, bic)
+ATOMIC_OPS(or, |=, or)
+ATOMIC_OPS(xor, ^=, xor)
+
+#define arch_atomic_andnot arch_atomic_andnot
+#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
+
+#endif
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 7a36d79b5b2f..ee88e1dbaab5 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -17,435 +17,16 @@
#define arch_atomic_read(v) READ_ONCE((v)->counter)
#ifdef CONFIG_ARC_HAS_LLSC
-
-#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
-
-#define ATOMIC_OP(op, c_op, asm_op) \
-static inline void arch_atomic_##op(int i, atomic_t *v) \
-{ \
- unsigned int val; \
- \
- __asm__ __volatile__( \
- "1: llock %[val], [%[ctr]] \n" \
- " " #asm_op " %[val], %[val], %[i] \n" \
- " scond %[val], [%[ctr]] \n" \
- " bnz 1b \n" \
- : [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \
- : [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \
- [i] "ir" (i) \
- : "cc"); \
-} \
-
-#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
-static inline int arch_atomic_##op##_return(int i, atomic_t *v) \
-{ \
- unsigned int val; \
- \
- /* \
- * Explicit full memory barrier needed before/after as \
- * LLOCK/SCOND themselves don't provide any such semantics \
- */ \
- smp_mb(); \
- \
- __asm__ __volatile__( \
- "1: llock %[val], [%[ctr]] \n" \
- " " #asm_op " %[val], %[val], %[i] \n" \
- " scond %[val], [%[ctr]] \n" \
- " bnz 1b \n" \
- : [val] "=&r" (val) \
- : [ctr] "r" (&v->counter), \
- [i] "ir" (i) \
- : "cc"); \
- \
- smp_mb(); \
- \
- return val; \
-}
-
-#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
-static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
-{ \
- unsigned int val, orig; \
- \
- /* \
- * Explicit full memory barrier needed before/after as \
- * LLOCK/SCOND themselves don't provide any such semantics \
- */ \
- smp_mb(); \
- \
- __asm__ __volatile__( \
- "1: llock %[orig], [%[ctr]] \n" \
- " " #asm_op " %[val], %[orig], %[i] \n" \
- " scond %[val], [%[ctr]] \n" \
- " bnz 1b \n" \
- : [val] "=&r" (val), \
- [orig] "=&r" (orig) \
- : [ctr] "r" (&v->counter), \
- [i] "ir" (i) \
- : "cc"); \
- \
- smp_mb(); \
- \
- return orig; \
-}
-
-#else /* !CONFIG_ARC_HAS_LLSC */
-
-#ifndef CONFIG_SMP
-
- /* violating atomic_xxx API locking protocol in UP for optimization sake */
-#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
-
+#include <asm/atomic-llsc.h>
#else
-
-static inline void arch_atomic_set(atomic_t *v, int i)
-{
- /*
- * Independent of hardware support, all of the atomic_xxx() APIs need
- * to follow the same locking rules to make sure that a "hardware"
- * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
- * sequence
- *
- * Thus atomic_set() despite being 1 insn (and seemingly atomic)
- * requires the locking.
- */
- unsigned long flags;
-
- atomic_ops_lock(flags);
- WRITE_ONCE(v->counter, i);
- atomic_ops_unlock(flags);
-}
-
-#define arch_atomic_set_release(v, i) arch_atomic_set((v), (i))
-
+#include <asm/atomic-spinlock.h>
#endif
-/*
- * Non hardware assisted Atomic-R-M-W
- * Locking would change to irq-disabling only (UP) and spinlocks (SMP)
- */
-
-#define ATOMIC_OP(op, c_op, asm_op) \
-static inline void arch_atomic_##op(int i, atomic_t *v) \
-{ \
- unsigned long flags; \
- \
- atomic_ops_lock(flags); \
- v->counter c_op i; \
- atomic_ops_unlock(flags); \
-}
-
-#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
-static inline int arch_atomic_##op##_return(int i, atomic_t *v) \
-{ \
- unsigned long flags; \
- unsigned long temp; \
- \
- /* \
- * spin lock/unlock provides the needed smp_mb() before/after \
- */ \
- atomic_ops_lock(flags); \
- temp = v->counter; \
- temp c_op i; \
- v->counter = temp; \
- atomic_ops_unlock(flags); \
- \
- return temp; \
-}
-
-#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
-static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
-{ \
- unsigned long flags; \
- unsigned long orig; \
- \
- /* \
- * spin lock/unlock provides the needed smp_mb() before/after \
- */ \
- atomic_ops_lock(flags); \
- orig = v->counter; \
- v->counter c_op i; \
- atomic_ops_unlock(flags); \
- \
- return orig; \
-}
-
-#endif /* !CONFIG_ARC_HAS_LLSC */
-
-#define ATOMIC_OPS(op, c_op, asm_op) \
- ATOMIC_OP(op, c_op, asm_op) \
- ATOMIC_OP_RETURN(op, c_op, asm_op) \
- ATOMIC_FETCH_OP(op, c_op, asm_op)
-
-ATOMIC_OPS(add, +=, add)
-ATOMIC_OPS(sub, -=, sub)
-
-#undef ATOMIC_OPS
-#define ATOMIC_OPS(op, c_op, asm_op) \
- ATOMIC_OP(op, c_op, asm_op) \
- ATOMIC_FETCH_OP(op, c_op, asm_op)
-
-ATOMIC_OPS(and, &=, and)
-ATOMIC_OPS(andnot, &= ~, bic)
-ATOMIC_OPS(or, |=, or)
-ATOMIC_OPS(xor, ^=, xor)
-
-#define arch_atomic_andnot arch_atomic_andnot
-#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
-
-#undef ATOMIC_OPS
-#undef ATOMIC_FETCH_OP
-#undef ATOMIC_OP_RETURN
-#undef ATOMIC_OP
-
#ifdef CONFIG_GENERIC_ATOMIC64
-
#include <asm-generic/atomic64.h>
-
-#else /* Kconfig ensures this is only enabled with needed h/w assist */
-
-/*
- * ARCv2 supports 64-bit exclusive load (LLOCKD) / store (SCONDD)
- * - The address HAS to be 64-bit aligned
- * - There are 2 semantics involved here:
- * = exclusive implies no interim update between load/store to same addr
- * = both words are observed/updated together: this is guaranteed even
- * for regular 64-bit load (LDD) / store (STD). Thus atomic64_set()
- * is NOT required to use LLOCKD+SCONDD, STD suffices
- */
-
-typedef struct {
- s64 __aligned(8) counter;
-} atomic64_t;
-
-#define ATOMIC64_INIT(a) { (a) }
-
-static inline s64 arch_atomic64_read(const atomic64_t *v)
-{
- s64 val;
-
- __asm__ __volatile__(
- " ldd %0, [%1] \n"
- : "=r"(val)
- : "r"(&v->counter));
-
- return val;
-}
-
-static inline void arch_atomic64_set(atomic64_t *v, s64 a)
-{
- /*
- * This could have been a simple assignment in "C" but would need
- * explicit volatile. Otherwise gcc optimizers could elide the store
- * which borked atomic64 self-test
- * In the inline asm version, memory clobber needed for exact same
- * reason, to tell gcc about the store.
- *
- * This however is not needed for sibling atomic64_add() etc since both
- * load/store are explicitly done in inline asm. As long as API is used
- * for each access, gcc has no way to optimize away any load/store
- */
- __asm__ __volatile__(
- " std %0, [%1] \n"
- :
- : "r"(a), "r"(&v->counter)
- : "memory");
-}
-
-#define ATOMIC64_OP(op, op1, op2) \
-static inline void arch_atomic64_##op(s64 a, atomic64_t *v) \
-{ \
- s64 val; \
- \
- __asm__ __volatile__( \
- "1: \n" \
- " llockd %0, [%1] \n" \
- " " #op1 " %L0, %L0, %L2 \n" \
- " " #op2 " %H0, %H0, %H2 \n" \
- " scondd %0, [%1] \n" \
- " bnz 1b \n" \
- : "=&r"(val) \
- : "r"(&v->counter), "ir"(a) \
- : "cc"); \
-} \
-
-#define ATOMIC64_OP_RETURN(op, op1, op2) \
-static inline s64 arch_atomic64_##op##_return(s64 a, atomic64_t *v) \
-{ \
- s64 val; \
- \
- smp_mb(); \
- \
- __asm__ __volatile__( \
- "1: \n" \
- " llockd %0, [%1] \n" \
- " " #op1 " %L0, %L0, %L2 \n" \
- " " #op2 " %H0, %H0, %H2 \n" \
- " scondd %0, [%1] \n" \
- " bnz 1b \n" \
- : [val] "=&r"(val) \
- : "r"(&v->counter), "ir"(a) \
- : "cc"); /* memory clobber comes from smp_mb() */ \
- \
- smp_mb(); \
- \
- return val; \
-}
-
-#define ATOMIC64_FETCH_OP(op, op1, op2) \
-static inline s64 arch_atomic64_fetch_##op(s64 a, atomic64_t *v) \
-{ \
- s64 val, orig; \
- \
- smp_mb(); \
- \
- __asm__ __volatile__( \
- "1: \n" \
- " llockd %0, [%2] \n" \
- " " #op1 " %L1, %L0, %L3 \n" \
- " " #op2 " %H1, %H0, %H3 \n" \
- " scondd %1, [%2] \n" \
- " bnz 1b \n" \
- : "=&r"(orig), "=&r"(val) \
- : "r"(&v->counter), "ir"(a) \
- : "cc"); /* memory clobber comes from smp_mb() */ \
- \
- smp_mb(); \
- \
- return orig; \
-}
-
-#define ATOMIC64_OPS(op, op1, op2) \
- ATOMIC64_OP(op, op1, op2) \
- ATOMIC64_OP_RETURN(op, op1, op2) \
- ATOMIC64_FETCH_OP(op, op1, op2)
-
-ATOMIC64_OPS(add, add.f, adc)
-ATOMIC64_OPS(sub, sub.f, sbc)
-ATOMIC64_OPS(and, and, and)
-ATOMIC64_OPS(andnot, bic, bic)
-ATOMIC64_OPS(or, or, or)
-ATOMIC64_OPS(xor, xor, xor)
-
-#define arch_atomic64_andnot arch_atomic64_andnot
-#define arch_atomic64_fetch_andnot arch_atomic64_fetch_andnot
-
-#undef ATOMIC64_OPS
-#undef ATOMIC64_FETCH_OP
-#undef ATOMIC64_OP_RETURN
-#undef ATOMIC64_OP
-
-static inline s64
-arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)
-{
- s64 prev;
-
- smp_mb();
-
- __asm__ __volatile__(
- "1: llockd %0, [%1] \n"
- " brne %L0, %L2, 2f \n"
- " brne %H0, %H2, 2f \n"
- " scondd %3, [%1] \n"
- " bnz 1b \n"
- "2: \n"
- : "=&r"(prev)
- : "r"(ptr), "ir"(expected), "r"(new)
- : "cc"); /* memory clobber comes from smp_mb() */
-
- smp_mb();
-
- return prev;
-}
-
-static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
-{
- s64 prev;
-
- smp_mb();
-
- __asm__ __volatile__(
- "1: llockd %0, [%1] \n"
- " scondd %2, [%1] \n"
- " bnz 1b \n"
- "2: \n"
- : "=&r"(prev)
- : "r"(ptr), "r"(new)
- : "cc"); /* memory clobber comes from smp_mb() */
-
- smp_mb();
-
- return prev;
-}
-
-/**
- * arch_atomic64_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic64_t
- *
- * The function returns the old value of *v minus 1, even if
- * the atomic variable, v, was not decremented.
- */
-
-static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
-{
- s64 val;
-
- smp_mb();
-
- __asm__ __volatile__(
- "1: llockd %0, [%1] \n"
- " sub.f %L0, %L0, 1 # w0 - 1, set C on borrow\n"
- " sub.c %H0, %H0, 1 # if C set, w1 - 1\n"
- " brlt %H0, 0, 2f \n"
- " scondd %0, [%1] \n"
- " bnz 1b \n"
- "2: \n"
- : "=&r"(val)
- : "r"(&v->counter)
- : "cc"); /* memory clobber comes from smp_mb() */
-
- smp_mb();
-
- return val;
-}
-#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
-
-/**
- * arch_atomic64_fetch_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, if it was not @u.
- * Returns the old value of @v
- */
-static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
-{
- s64 old, temp;
-
- smp_mb();
-
- __asm__ __volatile__(
- "1: llockd %0, [%2] \n"
- " brne %L0, %L4, 2f # continue to add since v != u \n"
- " breq.d %H0, %H4, 3f # return since v == u \n"
- "2: \n"
- " add.f %L1, %L0, %L3 \n"
- " adc %H1, %H0, %H3 \n"
- " scondd %1, [%2] \n"
- " bnz 1b \n"
- "3: \n"
- : "=&r"(old), "=&r" (temp)
- : "r"(&v->counter), "r"(a), "r"(u)
- : "cc"); /* memory clobber comes from smp_mb() */
-
- smp_mb();
-
- return old;
-}
-#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
-
-#endif /* !CONFIG_GENERIC_ATOMIC64 */
+#else
+#include <asm/atomic64-arcv2.h>
+#endif
#endif /* !__ASSEMBLY__ */
diff --git a/arch/arc/include/asm/atomic64-arcv2.h b/arch/arc/include/asm/atomic64-arcv2.h
new file mode 100644
index 000000000000..53996b11b551
--- /dev/null
+++ b/arch/arc/include/asm/atomic64-arcv2.h
@@ -0,0 +1,242 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/*
+ * ARCv2 supports 64-bit exclusive load (LLOCKD) / store (SCONDD)
+ * - The address HAS to be 64-bit aligned
+ */
+
+#ifndef _ASM_ARC_ATOMIC64_ARCV2_H
+#define _ASM_ARC_ATOMIC64_ARCV2_H
+
+typedef struct {
+ s64 __aligned(8) counter;
+} atomic64_t;
+
+#define ATOMIC64_INIT(a) { (a) }
+
+static inline s64 arch_atomic64_read(const atomic64_t *v)
+{
+ s64 val;
+
+ __asm__ __volatile__(
+ " ldd %0, [%1] \n"
+ : "=r"(val)
+ : "r"(&v->counter));
+
+ return val;
+}
+
+static inline void arch_atomic64_set(atomic64_t *v, s64 a)
+{
+ /*
+ * This could have been a simple assignment in "C" but would need
+ * explicit volatile. Otherwise gcc optimizers could elide the store
+ * which borked atomic64 self-test
+ * In the inline asm version, memory clobber needed for exact same
+ * reason, to tell gcc about the store.
+ *
+ * This however is not needed for sibling atomic64_add() etc since both
+ * load/store are explicitly done in inline asm. As long as API is used
+ * for each access, gcc has no way to optimize away any load/store
+ */
+ __asm__ __volatile__(
+ " std %0, [%1] \n"
+ :
+ : "r"(a), "r"(&v->counter)
+ : "memory");
+}
+
+#define ATOMIC64_OP(op, op1, op2) \
+static inline void arch_atomic64_##op(s64 a, atomic64_t *v) \
+{ \
+ s64 val; \
+ \
+ __asm__ __volatile__( \
+ "1: \n" \
+ " llockd %0, [%1] \n" \
+ " " #op1 " %L0, %L0, %L2 \n" \
+ " " #op2 " %H0, %H0, %H2 \n" \
+ " scondd %0, [%1] \n" \
+ " bnz 1b \n" \
+ : "=&r"(val) \
+ : "r"(&v->counter), "ir"(a) \
+ : "cc"); \
+} \
+
+#define ATOMIC64_OP_RETURN(op, op1, op2) \
+static inline s64 arch_atomic64_##op##_return(s64 a, atomic64_t *v) \
+{ \
+ s64 val; \
+ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ "1: \n" \
+ " llockd %0, [%1] \n" \
+ " " #op1 " %L0, %L0, %L2 \n" \
+ " " #op2 " %H0, %H0, %H2 \n" \
+ " scondd %0, [%1] \n" \
+ " bnz 1b \n" \
+ : [val] "=&r"(val) \
+ : "r"(&v->counter), "ir"(a) \
+ : "cc"); /* memory clobber comes from smp_mb() */ \
+ \
+ smp_mb(); \
+ \
+ return val; \
+}
+
+#define ATOMIC64_FETCH_OP(op, op1, op2) \
+static inline s64 arch_atomic64_fetch_##op(s64 a, atomic64_t *v) \
+{ \
+ s64 val, orig; \
+ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ "1: \n" \
+ " llockd %0, [%2] \n" \
+ " " #op1 " %L1, %L0, %L3 \n" \
+ " " #op2 " %H1, %H0, %H3 \n" \
+ " scondd %1, [%2] \n" \
+ " bnz 1b \n" \
+ : "=&r"(orig), "=&r"(val) \
+ : "r"(&v->counter), "ir"(a) \
+ : "cc"); /* memory clobber comes from smp_mb() */ \
+ \
+ smp_mb(); \
+ \
+ return orig; \
+}
+
+#define ATOMIC64_OPS(op, op1, op2) \
+ ATOMIC64_OP(op, op1, op2) \
+ ATOMIC64_OP_RETURN(op, op1, op2) \
+ ATOMIC64_FETCH_OP(op, op1, op2)
+
+ATOMIC64_OPS(add, add.f, adc)
+ATOMIC64_OPS(sub, sub.f, sbc)
+ATOMIC64_OPS(and, and, and)
+ATOMIC64_OPS(andnot, bic, bic)
+ATOMIC64_OPS(or, or, or)
+ATOMIC64_OPS(xor, xor, xor)
+
+#define arch_atomic64_andnot arch_atomic64_andnot
+#define arch_atomic64_fetch_andnot arch_atomic64_fetch_andnot
+
+#undef ATOMIC64_OPS
+#undef ATOMIC64_FETCH_OP
+#undef ATOMIC64_OP_RETURN
+#undef ATOMIC64_OP
+
+static inline s64
+arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)
+{
+ s64 prev;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llockd %0, [%1] \n"
+ " brne %L0, %L2, 2f \n"
+ " brne %H0, %H2, 2f \n"
+ " scondd %3, [%1] \n"
+ " bnz 1b \n"
+ "2: \n"
+ : "=&r"(prev)
+ : "r"(ptr), "ir"(expected), "r"(new)
+ : "cc"); /* memory clobber comes from smp_mb() */
+
+ smp_mb();
+
+ return prev;
+}
+
+static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
+{
+ s64 prev;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llockd %0, [%1] \n"
+ " scondd %2, [%1] \n"
+ " bnz 1b \n"
+ "2: \n"
+ : "=&r"(prev)
+ : "r"(ptr), "r"(new)
+ : "cc"); /* memory clobber comes from smp_mb() */
+
+ smp_mb();
+
+ return prev;
+}
+
+/**
+ * arch_atomic64_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic64_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+
+static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
+{
+ s64 val;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llockd %0, [%1] \n"
+ " sub.f %L0, %L0, 1 # w0 - 1, set C on borrow\n"
+ " sub.c %H0, %H0, 1 # if C set, w1 - 1\n"
+ " brlt %H0, 0, 2f \n"
+ " scondd %0, [%1] \n"
+ " bnz 1b \n"
+ "2: \n"
+ : "=&r"(val)
+ : "r"(&v->counter)
+ : "cc"); /* memory clobber comes from smp_mb() */
+
+ smp_mb();
+
+ return val;
+}
+#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
+
+/**
+ * arch_atomic64_fetch_add_unless - add unless the number is a given value
+ * @v: pointer of type atomic64_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, if it was not @u.
+ * Returns the old value of @v
+ */
+static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+{
+ s64 old, temp;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llockd %0, [%2] \n"
+ " brne %L0, %L4, 2f # continue to add since v != u \n"
+ " breq.d %H0, %H4, 3f # return since v == u \n"
+ "2: \n"
+ " add.f %L1, %L0, %L3 \n"
+ " adc %H1, %H0, %H3 \n"
+ " scondd %1, [%2] \n"
+ " bnz 1b \n"
+ "3: \n"
+ : "=&r"(old), "=&r" (temp)
+ : "r"(&v->counter), "r"(a), "r"(u)
+ : "cc"); /* memory clobber comes from smp_mb() */
+
+ smp_mb();
+
+ return old;
+}
+#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
+
+#endif
--
2.25.1
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