Commit 7e8bbe24 authored by Björn Töpel's avatar Björn Töpel Committed by Andrii Nakryiko
Browse files

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



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: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-3-bjorn.topel@gmail.com
parent 2882c48b

tools/lib/bpf/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -228,7 +228,6 @@ install_headers: $(BPF_HELPER_DEFS) 
		$(call do_install,bpf.h,$(prefix)/include/bpf,644); \

		$(call do_install,libbpf.h,$(prefix)/include/bpf,644); \

		$(call do_install,btf.h,$(prefix)/include/bpf,644); \

		$(call do_install,libbpf_util.h,$(prefix)/include/bpf,644); \

		$(call do_install,libbpf_common.h,$(prefix)/include/bpf,644); \

		$(call do_install,xsk.h,$(prefix)/include/bpf,644); \

		$(call do_install,bpf_helpers.h,$(prefix)/include/bpf,644); \

tools/lib/bpf/libbpf_util.h

deleted100644 → 0
+0 −82
Original line number Diff line number Diff line 
/* 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

tools/lib/bpf/xsk.h

+68 −2
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 * AF_XDP user-space access library.

 *

 * Copyright (c) 2018 - 2019 Intel Corporation.

 * Copyright (c) 2019 Facebook

 *

 * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>

 */
@@ -13,15 +14,80 @@ 


#include <stdio.h>

#include <stdint.h>

#include <stdbool.h>

#include <linux/if_xdp.h>



#include "libbpf.h"

#include "libbpf_util.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 */



/* Do not access these members directly. Use the functions below. */

#define DEFINE_XSK_RING(name) \

struct name { \