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-rw-r--r--arch/arc/include/asm/atomic64-arcv2.h250
1 files changed, 250 insertions, 0 deletions
diff --git a/arch/arc/include/asm/atomic64-arcv2.h b/arch/arc/include/asm/atomic64-arcv2.h
new file mode 100644
index 000000000000..c5a8010fdc97
--- /dev/null
+++ b/arch/arc/include/asm/atomic64-arcv2.h
@@ -0,0 +1,250 @@
+/* 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_relaxed(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" \
+ : [val] "=&r"(val) \
+ : "r"(&v->counter), "ir"(a) \
+ : "cc"); /* memory clobber comes from smp_mb() */ \
+ \
+ return val; \
+}
+
+#define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
+#define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
+
+#define ATOMIC64_FETCH_OP(op, op1, op2) \
+static inline s64 arch_atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v) \
+{ \
+ s64 val, orig; \
+ \
+ __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() */ \
+ \
+ return orig; \
+}
+
+#define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
+#define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed
+
+#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
+
+#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)
+
+#undef ATOMIC64_OPS
+#define ATOMIC64_OPS(op, op1, op2) \
+ ATOMIC64_OP(op, op1, op2) \
+ ATOMIC64_FETCH_OP(op, op1, op2)
+
+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
+
+#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
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.