linux-stable/samples/bpf/spintest.bpf.c
Daniel T. Lee 456d53554c samples/bpf: simplify spintest with kprobe.multi
With the introduction of kprobe.multi, it is now possible to attach
multiple kprobes to a single BPF program without the need for multiple
definitions. Additionally, this method supports wildcard-based
matching, allowing for further simplification of BPF programs. In here,
an asterisk (*) wildcard is used to map to all symbols relevant to
spin_{lock|unlock}.

Furthermore, since kprobe.multi handles symbol matching, this commit
eliminates the need for the previous logic of reading the ksym table to
verify the existence of symbols.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-10-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21 15:39:10 -07:00

60 lines
1.7 KiB
C

/* Copyright (c) 2016, Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include "vmlinux.h"
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#ifndef PERF_MAX_STACK_DEPTH
#define PERF_MAX_STACK_DEPTH 127
#endif
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, long);
__type(value, long);
__uint(max_entries, 1024);
} my_map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
__uint(key_size, sizeof(long));
__uint(value_size, sizeof(long));
__uint(max_entries, 1024);
} my_map2 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_STACK_TRACE);
__uint(key_size, sizeof(u32));
__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
__uint(max_entries, 10000);
} stackmap SEC(".maps");
#define PROG(foo) \
int foo(struct pt_regs *ctx) \
{ \
long v = PT_REGS_IP(ctx), *val; \
\
val = bpf_map_lookup_elem(&my_map, &v); \
bpf_map_update_elem(&my_map, &v, &v, BPF_ANY); \
bpf_map_update_elem(&my_map2, &v, &v, BPF_ANY); \
bpf_map_delete_elem(&my_map2, &v); \
bpf_get_stackid(ctx, &stackmap, BPF_F_REUSE_STACKID); \
return 0; \
}
/* add kprobes to all possible *spin* functions */
SEC("kprobe.multi/spin_*lock*")PROG(spin_lock)
SEC("kprobe.multi/*_spin_on_owner")PROG(spin_on_owner)
SEC("kprobe.multi/_raw_spin_*lock*")PROG(raw_spin_lock)
/* and to inner bpf helpers */
SEC("kprobe/htab_map_update_elem")PROG(p15)
SEC("kprobe/__htab_percpu_map_update_elem")PROG(p16)
SEC("kprobe/htab_map_alloc")PROG(p17)
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;