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43798bf372
Add bpf_map_update_elem() helper function which calls the sys_bpf syscall to update elements in bpf maps. Upcoming patches will use it to adjust data in map through the perf command line. Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1448372181-151723-4-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
99 lines
2.2 KiB
C
99 lines
2.2 KiB
C
/*
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* common eBPF ELF operations.
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*
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* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
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* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
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* Copyright (C) 2015 Huawei Inc.
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*/
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#include <stdlib.h>
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#include <memory.h>
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#include <unistd.h>
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#include <asm/unistd.h>
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#include <linux/bpf.h>
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#include "bpf.h"
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/*
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* When building perf, unistd.h is override. Define __NR_bpf is
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* required to be defined.
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*/
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#ifndef __NR_bpf
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# if defined(__i386__)
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# define __NR_bpf 357
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# elif defined(__x86_64__)
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# define __NR_bpf 321
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# elif defined(__aarch64__)
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# define __NR_bpf 280
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# else
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# error __NR_bpf not defined. libbpf does not support your arch.
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# endif
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#endif
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static __u64 ptr_to_u64(void *ptr)
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{
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return (__u64) (unsigned long) ptr;
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}
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static int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
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unsigned int size)
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{
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return syscall(__NR_bpf, cmd, attr, size);
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}
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int bpf_create_map(enum bpf_map_type map_type, int key_size,
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int value_size, int max_entries)
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{
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union bpf_attr attr;
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memset(&attr, '\0', sizeof(attr));
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attr.map_type = map_type;
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attr.key_size = key_size;
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attr.value_size = value_size;
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attr.max_entries = max_entries;
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return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
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}
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int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns,
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size_t insns_cnt, char *license,
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u32 kern_version, char *log_buf, size_t log_buf_sz)
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{
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int fd;
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union bpf_attr attr;
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bzero(&attr, sizeof(attr));
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attr.prog_type = type;
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attr.insn_cnt = (__u32)insns_cnt;
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attr.insns = ptr_to_u64(insns);
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attr.license = ptr_to_u64(license);
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attr.log_buf = ptr_to_u64(NULL);
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attr.log_size = 0;
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attr.log_level = 0;
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attr.kern_version = kern_version;
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fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
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if (fd >= 0 || !log_buf || !log_buf_sz)
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return fd;
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/* Try again with log */
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attr.log_buf = ptr_to_u64(log_buf);
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attr.log_size = log_buf_sz;
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attr.log_level = 1;
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log_buf[0] = 0;
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return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
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}
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int bpf_map_update_elem(int fd, void *key, void *value,
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u64 flags)
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{
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union bpf_attr attr;
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bzero(&attr, sizeof(attr));
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attr.map_fd = fd;
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attr.key = ptr_to_u64(key);
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attr.value = ptr_to_u64(value);
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attr.flags = flags;
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return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
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}
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