1/* 2 * SPDX-License-Identifier: GPL-2.0-or-later 3 * Load/store for 128-bit atomic operations, generic version. 4 * 5 * Copyright (C) 2018, 2023 Linaro, Ltd. 6 * 7 * See docs/devel/atomics.rst for discussion about the guarantees each 8 * atomic primitive is meant to provide. 9 */ 10 11#ifndef HOST_ATOMIC128_LDST_H 12#define HOST_ATOMIC128_LDST_H 13 14#if defined(CONFIG_ATOMIC128) 15# define HAVE_ATOMIC128_RO 1 16# define HAVE_ATOMIC128_RW 1 17 18static inline Int128 ATTRIBUTE_ATOMIC128_OPT 19atomic16_read_ro(const Int128 *ptr) 20{ 21 const __int128_t *ptr_align = __builtin_assume_aligned(ptr, 16); 22 Int128Alias r; 23 24 r.i = qatomic_read__nocheck(ptr_align); 25 return r.s; 26} 27 28static inline Int128 ATTRIBUTE_ATOMIC128_OPT 29atomic16_read_rw(Int128 *ptr) 30{ 31 return atomic16_read_ro(ptr); 32} 33 34static inline void ATTRIBUTE_ATOMIC128_OPT 35atomic16_set(Int128 *ptr, Int128 val) 36{ 37 __int128_t *ptr_align = __builtin_assume_aligned(ptr, 16); 38 Int128Alias v; 39 40 v.s = val; 41 qatomic_set__nocheck(ptr_align, v.i); 42} 43 44#elif defined(CONFIG_CMPXCHG128) 45# define HAVE_ATOMIC128_RO 0 46# define HAVE_ATOMIC128_RW 1 47 48Int128 QEMU_ERROR("unsupported atomic") atomic16_read_ro(const Int128 *ptr); 49 50static inline Int128 ATTRIBUTE_ATOMIC128_OPT 51atomic16_read_rw(Int128 *ptr) 52{ 53 /* Maybe replace 0 with 0, returning the old value. */ 54 Int128 z = int128_make64(0); 55 return atomic16_cmpxchg(ptr, z, z); 56} 57 58static inline void ATTRIBUTE_ATOMIC128_OPT 59atomic16_set(Int128 *ptr, Int128 val) 60{ 61 Int128Aligned *ptr_align = __builtin_assume_aligned(ptr, 16); 62 __int128_t old; 63 Int128Alias new; 64 65 new.s = val; 66 do { 67 old = *ptr_align; 68 } while (!__sync_bool_compare_and_swap_16(ptr_align, old, new.i)); 69} 70 71#else 72# define HAVE_ATOMIC128_RO 0 73# define HAVE_ATOMIC128_RW 0 74 75/* Fallback definitions that must be optimized away, or error. */ 76Int128 QEMU_ERROR("unsupported atomic") atomic16_read_ro(const Int128 *ptr); 77Int128 QEMU_ERROR("unsupported atomic") atomic16_read_rw(Int128 *ptr); 78void QEMU_ERROR("unsupported atomic") atomic16_set(Int128 *ptr, Int128 val); 79#endif 80 81#endif /* HOST_ATOMIC128_LDST_H */ 82