Commit 9e80114b authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov

selftests/bpf: Add tests for user- and non-CO-RE BPF_CORE_READ() variants

Add selftests validating that newly added variations of BPF_CORE_READ(), for
use with user-space addresses and for non-CO-RE reads, work as expected.
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201218235614.2284956-4-andrii@kernel.orgSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a4b09a9e
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
struct callback_head {
struct callback_head *next;
void (*func)(struct callback_head *head);
};
/* ___shuffled flavor is just an illusion for BPF code, it doesn't really
* exist and user-space needs to provide data in the memory layout that
* matches callback_head. We just defined ___shuffled flavor to make it easier
* to work with the skeleton
*/
struct callback_head___shuffled {
struct callback_head___shuffled *next;
void (*func)(struct callback_head *head);
};
#include "test_core_read_macros.skel.h"
void test_core_read_macros(void)
{
int duration = 0, err;
struct test_core_read_macros* skel;
struct test_core_read_macros__bss *bss;
struct callback_head u_probe_in;
struct callback_head___shuffled u_core_in;
skel = test_core_read_macros__open_and_load();
if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
return;
bss = skel->bss;
bss->my_pid = getpid();
/* next pointers have to be set from the kernel side */
bss->k_probe_in.func = (void *)(long)0x1234;
bss->k_core_in.func = (void *)(long)0xabcd;
u_probe_in.next = &u_probe_in;
u_probe_in.func = (void *)(long)0x5678;
bss->u_probe_in = &u_probe_in;
u_core_in.next = &u_core_in;
u_core_in.func = (void *)(long)0xdbca;
bss->u_core_in = &u_core_in;
err = test_core_read_macros__attach(skel);
if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
goto cleanup;
/* trigger tracepoint */
usleep(1);
ASSERT_EQ(bss->k_probe_out, 0x1234, "k_probe_out");
ASSERT_EQ(bss->k_core_out, 0xabcd, "k_core_out");
ASSERT_EQ(bss->u_probe_out, 0x5678, "u_probe_out");
ASSERT_EQ(bss->u_core_out, 0xdbca, "u_core_out");
cleanup:
test_core_read_macros__destroy(skel);
}
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2020 Facebook
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
char _license[] SEC("license") = "GPL";
/* shuffled layout for relocatable (CO-RE) reads */
struct callback_head___shuffled {
void (*func)(struct callback_head___shuffled *head);
struct callback_head___shuffled *next;
};
struct callback_head k_probe_in = {};
struct callback_head___shuffled k_core_in = {};
struct callback_head *u_probe_in = 0;
struct callback_head___shuffled *u_core_in = 0;
long k_probe_out = 0;
long u_probe_out = 0;
long k_core_out = 0;
long u_core_out = 0;
int my_pid = 0;
SEC("raw_tracepoint/sys_enter")
int handler(void *ctx)
{
int pid = bpf_get_current_pid_tgid() >> 32;
if (my_pid != pid)
return 0;
/* next pointers for kernel address space have to be initialized from
* BPF side, user-space mmaped addresses are stil user-space addresses
*/
k_probe_in.next = &k_probe_in;
__builtin_preserve_access_index(({k_core_in.next = &k_core_in;}));
k_probe_out = (long)BPF_PROBE_READ(&k_probe_in, next, next, func);
k_core_out = (long)BPF_CORE_READ(&k_core_in, next, next, func);
u_probe_out = (long)BPF_PROBE_READ_USER(u_probe_in, next, next, func);
u_core_out = (long)BPF_CORE_READ_USER(u_core_in, next, next, func);
return 0;
}
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