Commit 8fb9fb2f authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Alexei Starovoitov
Browse files

selftests/bpf: Query BPF_MAX_TRAMP_LINKS using BTF 



Do not hard-code the value, since for s390x it will be smaller than
for x86.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-4-iii@linux.ibm.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 390a07a9

tools/testing/selftests/bpf/prog_tests/fexit_stress.c

+14 −8
Original line number Diff line number Diff line
@@ -2,14 +2,19 @@ 
/* Copyright (c) 2019 Facebook */

#include <test_progs.h>



/* that's kernel internal BPF_MAX_TRAMP_PROGS define */

#define CNT 38



void serial_test_fexit_stress(void)

{

	int fexit_fd[CNT] = {};

	int link_fd[CNT] = {};

	int err, i;

	int bpf_max_tramp_links, err, i;

	int *fd, *fexit_fd, *link_fd;



	bpf_max_tramp_links = get_bpf_max_tramp_links();

	if (!ASSERT_GE(bpf_max_tramp_links, 1, "bpf_max_tramp_links"))

		return;

	fd = calloc(bpf_max_tramp_links * 2, sizeof(*fd));

	if (!ASSERT_OK_PTR(fd, "fd"))

		return;

	fexit_fd = fd;

	link_fd = fd + bpf_max_tramp_links;



	const struct bpf_insn trace_program[] = {

		BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -28,7 +33,7 @@ void serial_test_fexit_stress(void) 
		goto out;

	trace_opts.attach_btf_id = err;



	for (i = 0; i < CNT; i++) {

	for (i = 0; i < bpf_max_tramp_links; i++) {

		fexit_fd[i] = bpf_prog_load(BPF_PROG_TYPE_TRACING, NULL, "GPL",

					    trace_program,

					    sizeof(trace_program) / sizeof(struct bpf_insn),
@@ -44,10 +49,11 @@ void serial_test_fexit_stress(void) 
	ASSERT_OK(err, "bpf_prog_test_run_opts");



out:

	for (i = 0; i < CNT; i++) {

	for (i = 0; i < bpf_max_tramp_links; i++) {

		if (link_fd[i])

			close(link_fd[i]);

		if (fexit_fd[i])

			close(fexit_fd[i]);

	}

	free(fd);

}

tools/testing/selftests/bpf/prog_tests/trampoline_count.c

+11 −5
Original line number Diff line number Diff line
@@ -2,8 +2,6 @@ 
#define _GNU_SOURCE

#include <test_progs.h>



#define MAX_TRAMP_PROGS 38



struct inst {

	struct bpf_object *obj;

	struct bpf_link   *link;
@@ -37,14 +35,21 @@ void serial_test_trampoline_count(void) 
{

	char *file = "test_trampoline_count.bpf.o";

	char *const progs[] = { "fentry_test", "fmod_ret_test", "fexit_test" };

	struct inst inst[MAX_TRAMP_PROGS + 1] = {};

	int bpf_max_tramp_links, err, i, prog_fd;

	struct bpf_program *prog;

	struct bpf_link *link;

	int prog_fd, err, i;

	struct inst *inst;

	LIBBPF_OPTS(bpf_test_run_opts, opts);



	bpf_max_tramp_links = get_bpf_max_tramp_links();

	if (!ASSERT_GE(bpf_max_tramp_links, 1, "bpf_max_tramp_links"))

		return;

	inst = calloc(bpf_max_tramp_links + 1, sizeof(*inst));

	if (!ASSERT_OK_PTR(inst, "inst"))

		return;



	/* attach 'allowed' trampoline programs */

	for (i = 0; i < MAX_TRAMP_PROGS; i++) {

	for (i = 0; i < bpf_max_tramp_links; i++) {

		prog = load_prog(file, progs[i % ARRAY_SIZE(progs)], &inst[i]);

		if (!prog)

			goto cleanup;
@@ -91,4 +96,5 @@ void serial_test_trampoline_count(void) 
		bpf_link__destroy(inst[i].link);

		bpf_object__close(inst[i].obj);

	}

	free(inst);

}

tools/testing/selftests/bpf/test_progs.c

+38 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <sys/select.h>

#include <sys/socket.h>

#include <sys/un.h>

#include <bpf/btf.h>



static bool verbose(void)

{
@@ -967,6 +968,43 @@ int write_sysctl(const char *sysctl, const char *value) 
	return 0;

}



int get_bpf_max_tramp_links_from(struct btf *btf)

{

	const struct btf_enum *e;

	const struct btf_type *t;

	__u32 i, type_cnt;

	const char *name;

	__u16 j, vlen;



	for (i = 1, type_cnt = btf__type_cnt(btf); i < type_cnt; i++) {

		t = btf__type_by_id(btf, i);

		if (!t || !btf_is_enum(t) || t->name_off)

			continue;

		e = btf_enum(t);

		for (j = 0, vlen = btf_vlen(t); j < vlen; j++, e++) {

			name = btf__str_by_offset(btf, e->name_off);

			if (name && !strcmp(name, "BPF_MAX_TRAMP_LINKS"))

				return e->val;

		}

	}



	return -1;

}



int get_bpf_max_tramp_links(void)

{

	struct btf *vmlinux_btf;

	int ret;



	vmlinux_btf = btf__load_vmlinux_btf();

	if (!ASSERT_OK_PTR(vmlinux_btf, "vmlinux btf"))

		return -1;

	ret = get_bpf_max_tramp_links_from(vmlinux_btf);

	btf__free(vmlinux_btf);



	return ret;

}



#define MAX_BACKTRACE_SZ 128

void crash_handler(int signum)

{

tools/testing/selftests/bpf/test_progs.h

+2 −0
Original line number Diff line number Diff line
@@ -394,6 +394,8 @@ int kern_sync_rcu(void); 
int trigger_module_test_read(int read_sz);

int trigger_module_test_write(int write_sz);

int write_sysctl(const char *sysctl, const char *value);

int get_bpf_max_tramp_links_from(struct btf *btf);

int get_bpf_max_tramp_links(void);



#ifdef __x86_64__

#define SYS_NANOSLEEP_KPROBE_NAME "__x64_sys_nanosleep"