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Diffstat (limited to 'tools/testing/selftests/bpf/bpf_atomic.h')
| -rw-r--r-- | tools/testing/selftests/bpf/bpf_atomic.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bpf_atomic.h b/tools/testing/selftests/bpf/bpf_atomic.h new file mode 100644 index 000000000000..a9674e544322 --- /dev/null +++ b/tools/testing/selftests/bpf/bpf_atomic.h @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ +#ifndef BPF_ATOMIC_H +#define BPF_ATOMIC_H + +#include <vmlinux.h> +#include <bpf/bpf_helpers.h> +#include "bpf_experimental.h" + +extern bool CONFIG_X86_64 __kconfig __weak; + +/* + * __unqual_typeof(x) - Declare an unqualified scalar type, leaving + * non-scalar types unchanged, + * + * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char' + * is not type-compatible with 'signed char', and we define a separate case. + * + * This is copied verbatim from kernel's include/linux/compiler_types.h, but + * with default expression (for pointers) changed from (x) to (typeof(x)0). + * + * This is because LLVM has a bug where for lvalue (x), it does not get rid of + * an extra address_space qualifier, but does in case of rvalue (typeof(x)0). + * Hence, for pointers, we need to create an rvalue expression to get the + * desired type. See https://github.com/llvm/llvm-project/issues/53400. + */ +#define __scalar_type_to_expr_cases(type) \ + unsigned type : (unsigned type)0, signed type : (signed type)0 + +#define __unqual_typeof(x) \ + typeof(_Generic((x), \ + char: (char)0, \ + __scalar_type_to_expr_cases(char), \ + __scalar_type_to_expr_cases(short), \ + __scalar_type_to_expr_cases(int), \ + __scalar_type_to_expr_cases(long), \ + __scalar_type_to_expr_cases(long long), \ + default: (typeof(x))0)) + +/* No-op for BPF */ +#define cpu_relax() ({}) + +#define READ_ONCE(x) (*(volatile typeof(x) *)&(x)) + +#define WRITE_ONCE(x, val) ((*(volatile typeof(x) *)&(x)) = (val)) + +#define cmpxchg(p, old, new) __sync_val_compare_and_swap((p), old, new) + +#define try_cmpxchg(p, pold, new) \ + ({ \ + __unqual_typeof(*(pold)) __o = *(pold); \ + __unqual_typeof(*(p)) __r = cmpxchg(p, __o, new); \ + if (__r != __o) \ + *(pold) = __r; \ + __r == __o; \ + }) + +#define try_cmpxchg_relaxed(p, pold, new) try_cmpxchg(p, pold, new) + +#define try_cmpxchg_acquire(p, pold, new) try_cmpxchg(p, pold, new) + +#define smp_mb() \ + ({ \ + unsigned long __val; \ + __sync_fetch_and_add(&__val, 0); \ + }) + +#define smp_rmb() \ + ({ \ + if (!CONFIG_X86_64) \ + smp_mb(); \ + else \ + barrier(); \ + }) + +#define smp_wmb() \ + ({ \ + if (!CONFIG_X86_64) \ + smp_mb(); \ + else \ + barrier(); \ + }) + +/* Control dependency provides LOAD->STORE, provide LOAD->LOAD */ +#define smp_acquire__after_ctrl_dep() ({ smp_rmb(); }) + +#define smp_load_acquire(p) \ + ({ \ + __unqual_typeof(*(p)) __v = READ_ONCE(*(p)); \ + if (!CONFIG_X86_64) \ + smp_mb(); \ + barrier(); \ + __v; \ + }) + +#define smp_store_release(p, val) \ + ({ \ + if (!CONFIG_X86_64) \ + smp_mb(); \ + barrier(); \ + WRITE_ONCE(*(p), val); \ + }) + +#define smp_cond_load_relaxed_label(p, cond_expr, label) \ + ({ \ + typeof(p) __ptr = (p); \ + __unqual_typeof(*(p)) VAL; \ + for (;;) { \ + VAL = (__unqual_typeof(*(p)))READ_ONCE(*__ptr); \ + if (cond_expr) \ + break; \ + cond_break_label(label); \ + cpu_relax(); \ + } \ + (typeof(*(p)))VAL; \ + }) + +#define smp_cond_load_acquire_label(p, cond_expr, label) \ + ({ \ + __unqual_typeof(*p) __val = \ + smp_cond_load_relaxed_label(p, cond_expr, label); \ + smp_acquire__after_ctrl_dep(); \ + (typeof(*(p)))__val; \ + }) + +#define atomic_read(p) READ_ONCE((p)->counter) + +#define atomic_cond_read_relaxed_label(p, cond_expr, label) \ + smp_cond_load_relaxed_label(&(p)->counter, cond_expr, label) + +#define atomic_cond_read_acquire_label(p, cond_expr, label) \ + smp_cond_load_acquire_label(&(p)->counter, cond_expr, label) + +#define atomic_try_cmpxchg_relaxed(p, pold, new) \ + try_cmpxchg_relaxed(&(p)->counter, pold, new) + +#define atomic_try_cmpxchg_acquire(p, pold, new) \ + try_cmpxchg_acquire(&(p)->counter, pold, new) + +#endif /* BPF_ATOMIC_H */ |