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-rw-r--r--arch/arm/include/asm/atomic.h507
1 files changed, 507 insertions, 0 deletions
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
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+++ b/arch/arm/include/asm/atomic.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * arch/arm/include/asm/atomic.h
+ *
+ * Copyright (C) 1996 Russell King.
+ * Copyright (C) 2002 Deep Blue Solutions Ltd.
+ */
+#ifndef __ASM_ARM_ATOMIC_H
+#define __ASM_ARM_ATOMIC_H
+
+#include <linux/compiler.h>
+#include <linux/prefetch.h>
+#include <linux/types.h>
+#include <linux/irqflags.h>
+#include <asm/barrier.h>
+#include <asm/cmpxchg.h>
+
+#ifdef __KERNEL__
+
+/*
+ * On ARM, ordinary assignment (str instruction) doesn't clear the local
+ * strex/ldrex monitor on some implementations. The reason we can use it for
+ * atomic_set() is the clrex or dummy strex done on every exception return.
+ */
+#define arch_atomic_read(v) READ_ONCE((v)->counter)
+#define arch_atomic_set(v,i) WRITE_ONCE(((v)->counter), (i))
+
+#if __LINUX_ARM_ARCH__ >= 6
+
+/*
+ * ARMv6 UP and SMP safe atomic ops. We use load exclusive and
+ * store exclusive to ensure that these are atomic. We may loop
+ * to ensure that the update happens.
+ */
+
+#define ATOMIC_OP(op, c_op, asm_op) \
+static inline void arch_atomic_##op(int i, atomic_t *v) \
+{ \
+ unsigned long tmp; \
+ int result; \
+ \
+ prefetchw(&v->counter); \
+ __asm__ __volatile__("@ atomic_" #op "\n" \
+"1: ldrex %0, [%3]\n" \
+" " #asm_op " %0, %0, %4\n" \
+" strex %1, %0, [%3]\n" \
+" teq %1, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "Ir" (i) \
+ : "cc"); \
+} \
+
+#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
+static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v) \
+{ \
+ unsigned long tmp; \
+ int result; \
+ \
+ prefetchw(&v->counter); \
+ \
+ __asm__ __volatile__("@ atomic_" #op "_return\n" \
+"1: ldrex %0, [%3]\n" \
+" " #asm_op " %0, %0, %4\n" \
+" strex %1, %0, [%3]\n" \
+" teq %1, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "Ir" (i) \
+ : "cc"); \
+ \
+ return result; \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
+static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
+{ \
+ unsigned long tmp; \
+ int result, val; \
+ \
+ prefetchw(&v->counter); \
+ \
+ __asm__ __volatile__("@ atomic_fetch_" #op "\n" \
+"1: ldrex %0, [%4]\n" \
+" " #asm_op " %1, %0, %5\n" \
+" strex %2, %1, [%4]\n" \
+" teq %2, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (val), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "Ir" (i) \
+ : "cc"); \
+ \
+ return result; \
+}
+
+#define arch_atomic_add_return_relaxed arch_atomic_add_return_relaxed
+#define arch_atomic_sub_return_relaxed arch_atomic_sub_return_relaxed
+#define arch_atomic_fetch_add_relaxed arch_atomic_fetch_add_relaxed
+#define arch_atomic_fetch_sub_relaxed arch_atomic_fetch_sub_relaxed
+
+#define arch_atomic_fetch_and_relaxed arch_atomic_fetch_and_relaxed
+#define arch_atomic_fetch_andnot_relaxed arch_atomic_fetch_andnot_relaxed
+#define arch_atomic_fetch_or_relaxed arch_atomic_fetch_or_relaxed
+#define arch_atomic_fetch_xor_relaxed arch_atomic_fetch_xor_relaxed
+
+static inline int arch_atomic_cmpxchg_relaxed(atomic_t *ptr, int old, int new)
+{
+ int oldval;
+ unsigned long res;
+
+ prefetchw(&ptr->counter);
+
+ do {
+ __asm__ __volatile__("@ atomic_cmpxchg\n"
+ "ldrex %1, [%3]\n"
+ "mov %0, #0\n"
+ "teq %1, %4\n"
+ "strexeq %0, %5, [%3]\n"
+ : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
+ : "r" (&ptr->counter), "Ir" (old), "r" (new)
+ : "cc");
+ } while (res);
+
+ return oldval;
+}
+#define arch_atomic_cmpxchg_relaxed arch_atomic_cmpxchg_relaxed
+
+static inline int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
+{
+ int oldval, newval;
+ unsigned long tmp;
+
+ smp_mb();
+ prefetchw(&v->counter);
+
+ __asm__ __volatile__ ("@ atomic_add_unless\n"
+"1: ldrex %0, [%4]\n"
+" teq %0, %5\n"
+" beq 2f\n"
+" add %1, %0, %6\n"
+" strex %2, %1, [%4]\n"
+" teq %2, #0\n"
+" bne 1b\n"
+"2:"
+ : "=&r" (oldval), "=&r" (newval), "=&r" (tmp), "+Qo" (v->counter)
+ : "r" (&v->counter), "r" (u), "r" (a)
+ : "cc");
+
+ if (oldval != u)
+ smp_mb();
+
+ return oldval;
+}
+#define arch_atomic_fetch_add_unless arch_atomic_fetch_add_unless
+
+#else /* ARM_ARCH_6 */
+
+#ifdef CONFIG_SMP
+#error SMP not supported on pre-ARMv6 CPUs
+#endif
+
+#define ATOMIC_OP(op, c_op, asm_op) \
+static inline void arch_atomic_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ \
+ raw_local_irq_save(flags); \
+ v->counter c_op i; \
+ raw_local_irq_restore(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; \
+ int val; \
+ \
+ raw_local_irq_save(flags); \
+ v->counter c_op i; \
+ val = v->counter; \
+ raw_local_irq_restore(flags); \
+ \
+ return val; \
+}
+
+#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
+static inline int arch_atomic_fetch_##op(int i, atomic_t *v) \
+{ \
+ unsigned long flags; \
+ int val; \
+ \
+ raw_local_irq_save(flags); \
+ val = v->counter; \
+ v->counter c_op i; \
+ raw_local_irq_restore(flags); \
+ \
+ return val; \
+}
+
+static inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+ int ret;
+ unsigned long flags;
+
+ raw_local_irq_save(flags);
+ ret = v->counter;
+ if (likely(ret == old))
+ v->counter = new;
+ raw_local_irq_restore(flags);
+
+ return ret;
+}
+
+#define arch_atomic_fetch_andnot arch_atomic_fetch_andnot
+
+#endif /* __LINUX_ARM_ARCH__ */
+
+#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)
+
+#define arch_atomic_andnot arch_atomic_andnot
+
+#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, |=, orr)
+ATOMIC_OPS(xor, ^=, eor)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
+
+#define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), new))
+
+#ifndef CONFIG_GENERIC_ATOMIC64
+typedef struct {
+ s64 counter;
+} atomic64_t;
+
+#define ATOMIC64_INIT(i) { (i) }
+
+#ifdef CONFIG_ARM_LPAE
+static inline s64 arch_atomic64_read(const atomic64_t *v)
+{
+ s64 result;
+
+ __asm__ __volatile__("@ atomic64_read\n"
+" ldrd %0, %H0, [%1]"
+ : "=&r" (result)
+ : "r" (&v->counter), "Qo" (v->counter)
+ );
+
+ return result;
+}
+
+static inline void arch_atomic64_set(atomic64_t *v, s64 i)
+{
+ __asm__ __volatile__("@ atomic64_set\n"
+" strd %2, %H2, [%1]"
+ : "=Qo" (v->counter)
+ : "r" (&v->counter), "r" (i)
+ );
+}
+#else
+static inline s64 arch_atomic64_read(const atomic64_t *v)
+{
+ s64 result;
+
+ __asm__ __volatile__("@ atomic64_read\n"
+" ldrexd %0, %H0, [%1]"
+ : "=&r" (result)
+ : "r" (&v->counter), "Qo" (v->counter)
+ );
+
+ return result;
+}
+
+static inline void arch_atomic64_set(atomic64_t *v, s64 i)
+{
+ s64 tmp;
+
+ prefetchw(&v->counter);
+ __asm__ __volatile__("@ atomic64_set\n"
+"1: ldrexd %0, %H0, [%2]\n"
+" strexd %0, %3, %H3, [%2]\n"
+" teq %0, #0\n"
+" bne 1b"
+ : "=&r" (tmp), "=Qo" (v->counter)
+ : "r" (&v->counter), "r" (i)
+ : "cc");
+}
+#endif
+
+#define ATOMIC64_OP(op, op1, op2) \
+static inline void arch_atomic64_##op(s64 i, atomic64_t *v) \
+{ \
+ s64 result; \
+ unsigned long tmp; \
+ \
+ prefetchw(&v->counter); \
+ __asm__ __volatile__("@ atomic64_" #op "\n" \
+"1: ldrexd %0, %H0, [%3]\n" \
+" " #op1 " %Q0, %Q0, %Q4\n" \
+" " #op2 " %R0, %R0, %R4\n" \
+" strexd %1, %0, %H0, [%3]\n" \
+" teq %1, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "r" (i) \
+ : "cc"); \
+} \
+
+#define ATOMIC64_OP_RETURN(op, op1, op2) \
+static inline s64 \
+arch_atomic64_##op##_return_relaxed(s64 i, atomic64_t *v) \
+{ \
+ s64 result; \
+ unsigned long tmp; \
+ \
+ prefetchw(&v->counter); \
+ \
+ __asm__ __volatile__("@ atomic64_" #op "_return\n" \
+"1: ldrexd %0, %H0, [%3]\n" \
+" " #op1 " %Q0, %Q0, %Q4\n" \
+" " #op2 " %R0, %R0, %R4\n" \
+" strexd %1, %0, %H0, [%3]\n" \
+" teq %1, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "r" (i) \
+ : "cc"); \
+ \
+ return result; \
+}
+
+#define ATOMIC64_FETCH_OP(op, op1, op2) \
+static inline s64 \
+arch_atomic64_fetch_##op##_relaxed(s64 i, atomic64_t *v) \
+{ \
+ s64 result, val; \
+ unsigned long tmp; \
+ \
+ prefetchw(&v->counter); \
+ \
+ __asm__ __volatile__("@ atomic64_fetch_" #op "\n" \
+"1: ldrexd %0, %H0, [%4]\n" \
+" " #op1 " %Q1, %Q0, %Q5\n" \
+" " #op2 " %R1, %R0, %R5\n" \
+" strexd %2, %1, %H1, [%4]\n" \
+" teq %2, #0\n" \
+" bne 1b" \
+ : "=&r" (result), "=&r" (val), "=&r" (tmp), "+Qo" (v->counter) \
+ : "r" (&v->counter), "r" (i) \
+ : "cc"); \
+ \
+ return result; \
+}
+
+#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, adds, adc)
+ATOMIC64_OPS(sub, subs, sbc)
+
+#define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
+#define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
+#define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
+#define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed
+
+#undef ATOMIC64_OPS
+#define ATOMIC64_OPS(op, op1, op2) \
+ ATOMIC64_OP(op, op1, op2) \
+ ATOMIC64_FETCH_OP(op, op1, op2)
+
+#define arch_atomic64_andnot arch_atomic64_andnot
+
+ATOMIC64_OPS(and, and, and)
+ATOMIC64_OPS(andnot, bic, bic)
+ATOMIC64_OPS(or, orr, orr)
+ATOMIC64_OPS(xor, eor, eor)
+
+#define arch_atomic64_fetch_and_relaxed arch_atomic64_fetch_and_relaxed
+#define arch_atomic64_fetch_andnot_relaxed arch_atomic64_fetch_andnot_relaxed
+#define arch_atomic64_fetch_or_relaxed arch_atomic64_fetch_or_relaxed
+#define arch_atomic64_fetch_xor_relaxed arch_atomic64_fetch_xor_relaxed
+
+#undef ATOMIC64_OPS
+#undef ATOMIC64_FETCH_OP
+#undef ATOMIC64_OP_RETURN
+#undef ATOMIC64_OP
+
+static inline s64 arch_atomic64_cmpxchg_relaxed(atomic64_t *ptr, s64 old, s64 new)
+{
+ s64 oldval;
+ unsigned long res;
+
+ prefetchw(&ptr->counter);
+
+ do {
+ __asm__ __volatile__("@ atomic64_cmpxchg\n"
+ "ldrexd %1, %H1, [%3]\n"
+ "mov %0, #0\n"
+ "teq %1, %4\n"
+ "teqeq %H1, %H4\n"
+ "strexdeq %0, %5, %H5, [%3]"
+ : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
+ : "r" (&ptr->counter), "r" (old), "r" (new)
+ : "cc");
+ } while (res);
+
+ return oldval;
+}
+#define arch_atomic64_cmpxchg_relaxed arch_atomic64_cmpxchg_relaxed
+
+static inline s64 arch_atomic64_xchg_relaxed(atomic64_t *ptr, s64 new)
+{
+ s64 result;
+ unsigned long tmp;
+
+ prefetchw(&ptr->counter);
+
+ __asm__ __volatile__("@ atomic64_xchg\n"
+"1: ldrexd %0, %H0, [%3]\n"
+" strexd %1, %4, %H4, [%3]\n"
+" teq %1, #0\n"
+" bne 1b"
+ : "=&r" (result), "=&r" (tmp), "+Qo" (ptr->counter)
+ : "r" (&ptr->counter), "r" (new)
+ : "cc");
+
+ return result;
+}
+#define arch_atomic64_xchg_relaxed arch_atomic64_xchg_relaxed
+
+static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
+{
+ s64 result;
+ unsigned long tmp;
+
+ smp_mb();
+ prefetchw(&v->counter);
+
+ __asm__ __volatile__("@ atomic64_dec_if_positive\n"
+"1: ldrexd %0, %H0, [%3]\n"
+" subs %Q0, %Q0, #1\n"
+" sbc %R0, %R0, #0\n"
+" teq %R0, #0\n"
+" bmi 2f\n"
+" strexd %1, %0, %H0, [%3]\n"
+" teq %1, #0\n"
+" bne 1b\n"
+"2:"
+ : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
+ : "r" (&v->counter)
+ : "cc");
+
+ smp_mb();
+
+ return result;
+}
+#define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
+
+static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+{
+ s64 oldval, newval;
+ unsigned long tmp;
+
+ smp_mb();
+ prefetchw(&v->counter);
+
+ __asm__ __volatile__("@ atomic64_add_unless\n"
+"1: ldrexd %0, %H0, [%4]\n"
+" teq %0, %5\n"
+" teqeq %H0, %H5\n"
+" beq 2f\n"
+" adds %Q1, %Q0, %Q6\n"
+" adc %R1, %R0, %R6\n"
+" strexd %2, %1, %H1, [%4]\n"
+" teq %2, #0\n"
+" bne 1b\n"
+"2:"
+ : "=&r" (oldval), "=&r" (newval), "=&r" (tmp), "+Qo" (v->counter)
+ : "r" (&v->counter), "r" (u), "r" (a)
+ : "cc");
+
+ if (oldval != u)
+ smp_mb();
+
+ return oldval;
+}
+#define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
+
+#endif /* !CONFIG_GENERIC_ATOMIC64 */
+#endif
+#endif
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