2882c48bf8
In commit 291471dd15 ("libbpf, xsk: Add libbpf_smp_store_release
libbpf_smp_load_acquire") linux/compiler.h was added as a dependency
to xsk.h, which is the user-facing API. This makes it harder for
userspace application to consume the library. Here the header
inclusion is removed, and instead {READ,WRITE}_ONCE() is added
explicitly.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-2-bjorn.topel@gmail.com
83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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/* Copyright (c) 2019 Facebook */
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#ifndef __LIBBPF_LIBBPF_UTIL_H
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#define __LIBBPF_LIBBPF_UTIL_H
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Load-Acquire Store-Release barriers used by the XDP socket
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* library. The following macros should *NOT* be considered part of
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* the xsk.h API, and is subject to change anytime.
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*
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* LIBRARY INTERNAL
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*/
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#define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x)
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#define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
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#if defined(__i386__) || defined(__x86_64__)
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# define libbpf_smp_store_release(p, v) \
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do { \
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asm volatile("" : : : "memory"); \
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__XSK_WRITE_ONCE(*p, v); \
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} while (0)
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# define libbpf_smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
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asm volatile("" : : : "memory"); \
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___p1; \
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})
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#elif defined(__aarch64__)
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# define libbpf_smp_store_release(p, v) \
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asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
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# define libbpf_smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1; \
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asm volatile ("ldar %w0, %1" \
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: "=r" (___p1) : "Q" (*p) : "memory"); \
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___p1; \
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})
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#elif defined(__riscv)
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# define libbpf_smp_store_release(p, v) \
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do { \
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asm volatile ("fence rw,w" : : : "memory"); \
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__XSK_WRITE_ONCE(*p, v); \
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} while (0)
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# define libbpf_smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
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asm volatile ("fence r,rw" : : : "memory"); \
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___p1; \
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})
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#endif
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#ifndef libbpf_smp_store_release
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#define libbpf_smp_store_release(p, v) \
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do { \
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__sync_synchronize(); \
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__XSK_WRITE_ONCE(*p, v); \
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} while (0)
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#endif
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#ifndef libbpf_smp_load_acquire
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#define libbpf_smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
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__sync_synchronize(); \
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___p1; \
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})
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#endif
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/* LIBRARY INTERNAL -- END */
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif
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