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linux/tools/lib/bpf/libbpf_util.h

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tools/bpf: move libbpf pr_* debug print functions to headers A global function libbpf_print, which is invisible outside the shared library, is defined to print based on levels. The pr_warning, pr_info and pr_debug macros are moved into the newly created header common.h. So any .c file including common.h can use these macros directly. Currently btf__new and btf_ext__new API has an argument getting __pr_debug function pointer into btf.c so the debugging information can be printed there. This patch removed this parameter from btf__new and btf_ext__new and directly using pr_debug in btf.c. Another global function libbpf_print_level_available, also invisible outside the shared library, can test whether a particular level debug printing is available or not. It is used in btf.c to test whether DEBUG level debug printing is availabl or not, based on which the log buffer will be allocated when loading btf to the kernel. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-01 16:14:14 -08:00
/* 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
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
/* Use these barrier functions instead of smp_[rw]mb() when they are
* used in a libbpf header file. That way they can be built into the
* application that uses libbpf.
*/
#if defined(__i386__) || defined(__x86_64__)
# define libbpf_smp_rmb() asm volatile("" : : : "memory")
# define libbpf_smp_wmb() asm volatile("" : : : "memory")
# define libbpf_smp_mb() \
asm volatile("lock; addl $0,-4(%%rsp)" : : : "memory", "cc")
libbpf: optimize barrier for XDP socket rings The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:12 +02:00
/* Hinders stores to be observed before older loads. */
# define libbpf_smp_rwmb() asm volatile("" : : : "memory")
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
#elif defined(__aarch64__)
# define libbpf_smp_rmb() asm volatile("dmb ishld" : : : "memory")
# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory")
# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory")
libbpf: optimize barrier for XDP socket rings The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:12 +02:00
# define libbpf_smp_rwmb() libbpf_smp_mb()
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
#elif defined(__arm__)
/* These are only valid for armv7 and above */
# define libbpf_smp_rmb() asm volatile("dmb ish" : : : "memory")
# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory")
# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory")
libbpf: optimize barrier for XDP socket rings The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:12 +02:00
# define libbpf_smp_rwmb() libbpf_smp_mb()
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
#else
libbpf: remove compile time warning from libbpf_util.h Having a helpful compile time warning in libbpf_util.h is not a good idea since all warnings are treated as errors. Change this into a comment in the code instead. Fixes: b7e3a28019c9 ("libbpf: remove dependency on barrier.h in xsk.h") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-18 09:21:10 +02:00
/* Architecture missing native barrier functions. */
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
# define libbpf_smp_rmb() __sync_synchronize()
# define libbpf_smp_wmb() __sync_synchronize()
# define libbpf_smp_mb() __sync_synchronize()
libbpf: optimize barrier for XDP socket rings The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:12 +02:00
# define libbpf_smp_rwmb() __sync_synchronize()
libbpf: remove dependency on barrier.h in xsk.h The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16 14:58:11 +02:00
#endif
tools/bpf: move libbpf pr_* debug print functions to headers A global function libbpf_print, which is invisible outside the shared library, is defined to print based on levels. The pr_warning, pr_info and pr_debug macros are moved into the newly created header common.h. So any .c file including common.h can use these macros directly. Currently btf__new and btf_ext__new API has an argument getting __pr_debug function pointer into btf.c so the debugging information can be printed there. This patch removed this parameter from btf__new and btf_ext__new and directly using pr_debug in btf.c. Another global function libbpf_print_level_available, also invisible outside the shared library, can test whether a particular level debug printing is available or not. It is used in btf.c to test whether DEBUG level debug printing is availabl or not, based on which the log buffer will be allocated when loading btf to the kernel. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-01 16:14:14 -08:00
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif
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