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https://github.com/torvalds/linux
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3b2ad50225
Add selftest validating various aspects of statically linking BTF-defined map
definitions. Legacy map definitions do not support extern resolution between
object files. Some of the aspects validated:
- correct resolution of extern maps against concrete map definitions;
- extern maps can currently only specify map type and key/value size and/or
type information;
- weak concrete map definitions are resolved properly.
Static map definitions are not yet supported by libbpf, so they are not
explicitly tested, though manual testing showes that BPF linker handles them
properly.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210423181348.1801389-18-andrii@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) 2021 Facebook */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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/* modifiers and typedefs are ignored when comparing key/value types */
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typedef struct my_key { long x; } key_type;
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typedef struct my_value { long x; } value_type;
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extern struct {
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__uint(max_entries, 16);
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__type(key, key_type);
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__type(value, value_type);
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__uint(type, BPF_MAP_TYPE_HASH);
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} map1 SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, int);
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__type(value, int);
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__uint(max_entries, 8);
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} map2 SEC(".maps");
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/* this definition will lose, but it has to exactly match the winner */
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, int);
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__type(value, int);
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__uint(max_entries, 16);
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} map_weak __weak SEC(".maps");
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int output_first2;
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int output_second2;
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int output_weak2;
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SEC("raw_tp/sys_enter")
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int BPF_PROG(handler_enter2)
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{
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/* update values with key = 2 */
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int key = 2, val = 2;
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key_type key_struct = { .x = 2 };
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value_type val_struct = { .x = 2000 };
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bpf_map_update_elem(&map1, &key_struct, &val_struct, 0);
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bpf_map_update_elem(&map2, &key, &val, 0);
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bpf_map_update_elem(&map_weak, &key, &val, 0);
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return 0;
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}
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SEC("raw_tp/sys_exit")
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int BPF_PROG(handler_exit2)
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{
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/* lookup values with key = 1, set in another file */
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int key = 1, *val;
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key_type key_struct = { .x = 1 };
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value_type *value_struct;
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value_struct = bpf_map_lookup_elem(&map1, &key_struct);
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if (value_struct)
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output_first2 = value_struct->x;
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val = bpf_map_lookup_elem(&map2, &key);
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if (val)
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output_second2 = *val;
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val = bpf_map_lookup_elem(&map_weak, &key);
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if (val)
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output_weak2 = *val;
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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