From: Will Deacon <will.deacon@xxxxxxx> Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). This patch implements the LSE variants. Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1461344493-8262-2-git-send-email-will.deacon@xxxxxxx --- arch/arm64/include/asm/atomic_lse.h | 172 ++++++++++++++++++++++++++++++++++++ 1 file changed, 172 insertions(+) --- a/arch/arm64/include/asm/atomic_lse.h +++ b/arch/arm64/include/asm/atomic_lse.h @@ -46,6 +46,38 @@ ATOMIC_OP(add, stadd) #undef ATOMIC_OP +#define ATOMIC_FETCH_OP(name, mb, op, asm_op, cl...) \ +static inline int atomic_fetch_##op##name(int i, atomic_t *v) \ +{ \ + register int w0 asm ("w0") = i; \ + register atomic_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + __LL_SC_ATOMIC(fetch_##op##name), \ + /* LSE atomics */ \ +" " #asm_op #mb " %w[i], %w[i], %[v]") \ + : [i] "+r" (w0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return w0; \ +} + +#define ATOMIC_FETCH_OPS(op, asm_op) \ + ATOMIC_FETCH_OP(_relaxed, , op, asm_op) \ + ATOMIC_FETCH_OP(_acquire, a, op, asm_op, "memory") \ + ATOMIC_FETCH_OP(_release, l, op, asm_op, "memory") \ + ATOMIC_FETCH_OP( , al, op, asm_op, "memory") + +ATOMIC_FETCH_OPS(andnot, ldclr) +ATOMIC_FETCH_OPS(or, ldset) +ATOMIC_FETCH_OPS(xor, ldeor) +ATOMIC_FETCH_OPS(add, ldadd) + +#undef ATOMIC_FETCH_OP +#undef ATOMIC_FETCH_OPS + #define ATOMIC_OP_ADD_RETURN(name, mb, cl...) \ static inline int atomic_add_return##name(int i, atomic_t *v) \ { \ @@ -90,6 +122,33 @@ static inline void atomic_and(int i, ato : __LL_SC_CLOBBERS); } +#define ATOMIC_FETCH_OP_AND(name, mb, cl...) \ +static inline int atomic_fetch_and##name(int i, atomic_t *v) \ +{ \ + register int w0 asm ("w0") = i; \ + register atomic_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + " nop\n" \ + __LL_SC_ATOMIC(fetch_and##name), \ + /* LSE atomics */ \ + " mvn %w[i], %w[i]\n" \ + " ldclr" #mb " %w[i], %w[i], %[v]") \ + : [i] "+r" (w0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return w0; \ +} + +ATOMIC_FETCH_OP_AND(_relaxed, ) +ATOMIC_FETCH_OP_AND(_acquire, a, "memory") +ATOMIC_FETCH_OP_AND(_release, l, "memory") +ATOMIC_FETCH_OP_AND( , al, "memory") + +#undef ATOMIC_FETCH_OP_AND + static inline void atomic_sub(int i, atomic_t *v) { register int w0 asm ("w0") = i; @@ -135,6 +194,33 @@ ATOMIC_OP_SUB_RETURN(_release, l, "memo ATOMIC_OP_SUB_RETURN( , al, "memory") #undef ATOMIC_OP_SUB_RETURN + +#define ATOMIC_FETCH_OP_SUB(name, mb, cl...) \ +static inline int atomic_fetch_sub##name(int i, atomic_t *v) \ +{ \ + register int w0 asm ("w0") = i; \ + register atomic_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + " nop\n" \ + __LL_SC_ATOMIC(fetch_sub##name), \ + /* LSE atomics */ \ + " neg %w[i], %w[i]\n" \ + " ldadd" #mb " %w[i], %w[i], %[v]") \ + : [i] "+r" (w0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return w0; \ +} + +ATOMIC_FETCH_OP_SUB(_relaxed, ) +ATOMIC_FETCH_OP_SUB(_acquire, a, "memory") +ATOMIC_FETCH_OP_SUB(_release, l, "memory") +ATOMIC_FETCH_OP_SUB( , al, "memory") + +#undef ATOMIC_FETCH_OP_SUB #undef __LL_SC_ATOMIC #define __LL_SC_ATOMIC64(op) __LL_SC_CALL(atomic64_##op) @@ -158,6 +244,38 @@ ATOMIC64_OP(add, stadd) #undef ATOMIC64_OP +#define ATOMIC64_FETCH_OP(name, mb, op, asm_op, cl...) \ +static inline long atomic64_fetch_##op##name(long i, atomic64_t *v) \ +{ \ + register long x0 asm ("x0") = i; \ + register atomic64_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + __LL_SC_ATOMIC64(fetch_##op##name), \ + /* LSE atomics */ \ +" " #asm_op #mb " %[i], %[i], %[v]") \ + : [i] "+r" (x0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return x0; \ +} + +#define ATOMIC64_FETCH_OPS(op, asm_op) \ + ATOMIC64_FETCH_OP(_relaxed, , op, asm_op) \ + ATOMIC64_FETCH_OP(_acquire, a, op, asm_op, "memory") \ + ATOMIC64_FETCH_OP(_release, l, op, asm_op, "memory") \ + ATOMIC64_FETCH_OP( , al, op, asm_op, "memory") + +ATOMIC64_FETCH_OPS(andnot, ldclr) +ATOMIC64_FETCH_OPS(or, ldset) +ATOMIC64_FETCH_OPS(xor, ldeor) +ATOMIC64_FETCH_OPS(add, ldadd) + +#undef ATOMIC64_FETCH_OP +#undef ATOMIC64_FETCH_OPS + #define ATOMIC64_OP_ADD_RETURN(name, mb, cl...) \ static inline long atomic64_add_return##name(long i, atomic64_t *v) \ { \ @@ -202,6 +320,33 @@ static inline void atomic64_and(long i, : __LL_SC_CLOBBERS); } +#define ATOMIC64_FETCH_OP_AND(name, mb, cl...) \ +static inline long atomic64_fetch_and##name(long i, atomic64_t *v) \ +{ \ + register long x0 asm ("w0") = i; \ + register atomic64_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + " nop\n" \ + __LL_SC_ATOMIC64(fetch_and##name), \ + /* LSE atomics */ \ + " mvn %[i], %[i]\n" \ + " ldclr" #mb " %[i], %[i], %[v]") \ + : [i] "+r" (x0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return x0; \ +} + +ATOMIC64_FETCH_OP_AND(_relaxed, ) +ATOMIC64_FETCH_OP_AND(_acquire, a, "memory") +ATOMIC64_FETCH_OP_AND(_release, l, "memory") +ATOMIC64_FETCH_OP_AND( , al, "memory") + +#undef ATOMIC64_FETCH_OP_AND + static inline void atomic64_sub(long i, atomic64_t *v) { register long x0 asm ("x0") = i; @@ -248,6 +393,33 @@ ATOMIC64_OP_SUB_RETURN( , al, "me #undef ATOMIC64_OP_SUB_RETURN +#define ATOMIC64_FETCH_OP_SUB(name, mb, cl...) \ +static inline long atomic64_fetch_sub##name(long i, atomic64_t *v) \ +{ \ + register long x0 asm ("w0") = i; \ + register atomic64_t *x1 asm ("x1") = v; \ + \ + asm volatile(ARM64_LSE_ATOMIC_INSN( \ + /* LL/SC */ \ + " nop\n" \ + __LL_SC_ATOMIC64(fetch_sub##name), \ + /* LSE atomics */ \ + " neg %[i], %[i]\n" \ + " ldadd" #mb " %[i], %[i], %[v]") \ + : [i] "+r" (x0), [v] "+Q" (v->counter) \ + : "r" (x1) \ + : __LL_SC_CLOBBERS, ##cl); \ + \ + return x0; \ +} + +ATOMIC64_FETCH_OP_SUB(_relaxed, ) +ATOMIC64_FETCH_OP_SUB(_acquire, a, "memory") +ATOMIC64_FETCH_OP_SUB(_release, l, "memory") +ATOMIC64_FETCH_OP_SUB( , al, "memory") + +#undef ATOMIC64_FETCH_OP_SUB + static inline long atomic64_dec_if_positive(atomic64_t *v) { register long x0 asm ("x0") = (long)v; 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