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libbpf: xsk: Move barriers from libbpf_util.h to xsk.h

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The only user of libbpf_util.h is xsk.h. Move the barriers to xsk.h,
and remove libbpf_util.h. The barriers are used as an implementation
detail, and should not be considered part of the stable API.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-3-bjorn.topel@gmail.com
This commit is contained in:
Björn Töpel
2021-03-10 09:09:29 +01:00
committed by Andrii Nakryiko
parent 27db7104d5
commit b727e2deca
2 changed files with 68 additions and 84 deletions
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82
src/libbpf_util.h
View File

@@ -1,82 +0,0 @@
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (c) 2019 Facebook */
#ifndef __LIBBPF_LIBBPF_UTIL_H
#define __LIBBPF_LIBBPF_UTIL_H
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Load-Acquire Store-Release barriers used by the XDP socket
* library. The following macros should *NOT* be considered part of
* the xsk.h API, and is subject to change anytime.
*
* LIBRARY INTERNAL
*/
#define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x)
#define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
#if defined(__i386__) || defined(__x86_64__)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile("" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile("" : : : "memory"); \
___p1; \
})
#elif defined(__aarch64__)
# define libbpf_smp_store_release(p, v) \
asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1; \
asm volatile ("ldar %w0, %1" \
: "=r" (___p1) : "Q" (*p) : "memory"); \
___p1; \
})
#elif defined(__riscv)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile ("fence rw,w" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile ("fence r,rw" : : : "memory"); \
___p1; \
})
#endif
#ifndef libbpf_smp_store_release
#define libbpf_smp_store_release(p, v) \
do { \
__sync_synchronize(); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
#endif
#ifndef libbpf_smp_load_acquire
#define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
__sync_synchronize(); \
___p1; \
})
#endif
/* LIBRARY INTERNAL -- END */
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif

70
src/xsk.h
View File

@@ -3,7 +3,8 @@
/* /*
* AF_XDP user-space access library. * AF_XDP user-space access library.
* *
* Copyright(c) 2018 - 2019 Intel Corporation. * Copyright (c) 2018 - 2019 Intel Corporation.
* Copyright (c) 2019 Facebook
* *
* Author(s): Magnus Karlsson <magnus.karlsson@intel.com> * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
*/ */
@@ -13,15 +14,80 @@
#include <stdio.h> #include <stdio.h>
#include <stdint.h> #include <stdint.h>
#include <stdbool.h>
#include <linux/if_xdp.h> #include <linux/if_xdp.h>
#include "libbpf.h" #include "libbpf.h"
#include "libbpf_util.h"
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
/* Load-Acquire Store-Release barriers used by the XDP socket
* library. The following macros should *NOT* be considered part of
* the xsk.h API, and is subject to change anytime.
*
* LIBRARY INTERNAL
*/
#define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x)
#define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
#if defined(__i386__) || defined(__x86_64__)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile("" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile("" : : : "memory"); \
___p1; \
})
#elif defined(__aarch64__)
# define libbpf_smp_store_release(p, v) \
asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1; \
asm volatile ("ldar %w0, %1" \
: "=r" (___p1) : "Q" (*p) : "memory"); \
___p1; \
})
#elif defined(__riscv)
# define libbpf_smp_store_release(p, v) \
do { \
asm volatile ("fence rw,w" : : : "memory"); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
# define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
asm volatile ("fence r,rw" : : : "memory"); \
___p1; \
})
#endif
#ifndef libbpf_smp_store_release
#define libbpf_smp_store_release(p, v) \
do { \
__sync_synchronize(); \
__XSK_WRITE_ONCE(*p, v); \
} while (0)
#endif
#ifndef libbpf_smp_load_acquire
#define libbpf_smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \
__sync_synchronize(); \
___p1; \
})
#endif
/* LIBRARY INTERNAL -- END */
/* Do not access these members directly. Use the functions below. */ /* Do not access these members directly. Use the functions below. */
#define DEFINE_XSK_RING(name) \ #define DEFINE_XSK_RING(name) \
struct name { \ struct name { \