5e61f27070
Kernel version enforcement for kprobes/kretprobes was removed from
5.0 kernel in 6c4fc209fcf9 ("bpf: remove useless version check for prog load").
Since then, BPF programs were specifying SEC("version") just to please
libbpf. We should stop enforcing this in libbpf, if even kernel doesn't
care. Furthermore, libbpf now will pre-populate current kernel version
of the host system, in case we are still running on old kernel.
This patch also removes __bpf_object__open_xattr from libbpf.h, as
nothing in libbpf is relying on having it in that header. That function
was never exported as LIBBPF_API and even name suggests its internal
version. So this should be safe to remove, as it doesn't break ABI.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
77 lines
1.7 KiB
C
77 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2018 Facebook
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#include <linux/bpf.h>
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#include "bpf_helpers.h"
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#ifndef PERF_MAX_STACK_DEPTH
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#define PERF_MAX_STACK_DEPTH 127
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#endif
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, __u32);
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__type(value, __u32);
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} control_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 16384);
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__type(key, __u32);
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__type(value, __u32);
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} stackid_hmap SEC(".maps");
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typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];
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struct {
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__uint(type, BPF_MAP_TYPE_STACK_TRACE);
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__uint(max_entries, 16384);
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__uint(key_size, sizeof(__u32));
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__uint(value_size, sizeof(stack_trace_t));
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} stackmap SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 16384);
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__type(key, __u32);
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__type(value, stack_trace_t);
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} stack_amap SEC(".maps");
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/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
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struct sched_switch_args {
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unsigned long long pad;
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char prev_comm[16];
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int prev_pid;
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int prev_prio;
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long long prev_state;
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char next_comm[16];
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int next_pid;
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int next_prio;
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};
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SEC("tracepoint/sched/sched_switch")
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int oncpu(struct sched_switch_args *ctx)
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{
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__u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
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__u32 key = 0, val = 0, *value_p;
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void *stack_p;
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value_p = bpf_map_lookup_elem(&control_map, &key);
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if (value_p && *value_p)
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return 0; /* skip if non-zero *value_p */
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/* The size of stackmap and stackid_hmap should be the same */
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key = bpf_get_stackid(ctx, &stackmap, 0);
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if ((int)key >= 0) {
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bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
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stack_p = bpf_map_lookup_elem(&stack_amap, &key);
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if (stack_p)
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bpf_get_stack(ctx, stack_p, max_len, 0);
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}
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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