diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_arena.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_arena.c index 1c04473fb42d..e7580b9f0fc2 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_arena.c +++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_arena.c @@ -13,6 +13,7 @@ #include "struct_ops_arena_member_fail__mismatch_mem.skel.h" #include "struct_ops_arena_member_fail__write.skel.h" #include "struct_ops_arena_member_fail__no_arena.skel.h" +#include "struct_ops_arena_autobind.skel.h" #if defined(__x86_64__) || defined(__aarch64__) /* @@ -145,6 +146,119 @@ static void arena_member(void) struct_ops_arena_member__destroy(skel); } +/* @prog_fd lists exactly one map, the one with @map_id. */ +static void assert_prog_map(int prog_fd, __u32 map_id, const char *name) +{ + __u32 map_ids[2] = {}, len = sizeof(struct bpf_prog_info); + struct bpf_prog_info info = { + .nr_map_ids = ARRAY_SIZE(map_ids), + .map_ids = ptr_to_u64(map_ids), + }; + int err; + + err = bpf_prog_get_info_by_fd(prog_fd, &info, &len); + if (!ASSERT_OK(err, name)) + return; + if (!ASSERT_EQ(info.nr_map_ids, 1, name)) + return; + ASSERT_EQ(map_ids[0], map_id, name); +} + +/* + * libbpf binds the arena of an object to every program in it: a callback + * with an __arena argument loads without referring to the arena, and an + * unrelated program gets the arena as well. + */ +static void arena_autobind(void) +{ + struct struct_ops_arena_autobind *skel; + struct bpf_map_info info = {}; + __u32 len = sizeof(info); + int err; + + skel = struct_ops_arena_autobind__open_and_load(); + if (!ASSERT_OK_PTR(skel, "struct_ops_arena_autobind__open_and_load")) + return; + + err = bpf_map_get_info_by_fd(bpf_map__fd(skel->maps.arena), &info, &len); + if (!ASSERT_OK(err, "arena_info")) + goto out; + assert_prog_map(bpf_program__fd(skel->progs.test_arena_cb), info.id, "test_arena_cb"); + assert_prog_map(bpf_program__fd(skel->progs.unrelated), info.id, "unrelated"); + + attach_and_trigger(skel->maps.testmod_arena_autobind, skel->progs.trigger); +out: + struct_ops_arena_autobind__destroy(skel); +} + +/* + * The same binding through bpf_object__prepare() and bpf_program__clone(), the + * way veristat loads a program: the arena takes slot 0 of a continuous + * fd_array, next to the module BTF of the kfunc the trigger calls. + */ +static void arena_autobind_clone(void) +{ + struct struct_ops_arena_autobind *skel; + struct bpf_map_info info = {}; + __u32 len = sizeof(info); + struct bpf_program *prog; + int err, fd; + + skel = struct_ops_arena_autobind__open(); + if (!ASSERT_OK_PTR(skel, "struct_ops_arena_autobind__open")) + return; + + err = bpf_object__prepare(skel->obj); + if (!ASSERT_OK(err, "prepare")) + goto out; + err = bpf_map_get_info_by_fd(bpf_map__fd(skel->maps.arena), &info, &len); + if (!ASSERT_OK(err, "arena_info")) + goto out; + bpf_object__for_each_program(prog, skel->obj) { + fd = bpf_program__clone(prog, NULL); + if (!ASSERT_GE(fd, 0, bpf_program__name(prog))) + continue; + assert_prog_map(fd, info.id, bpf_program__name(prog)); + close(fd); + } +out: + struct_ops_arena_autobind__destroy(skel); +} + +/* + * An arena exclusive to a program is bound to that program all the same: the + * kernel checks an exclusive map against the digest of the final program, so + * the binding through the fd_array passes for the program the map is + * exclusive to. + */ +static void arena_autobind_excl(void) +{ + struct struct_ops_arena_autobind *skel; + struct bpf_map_info info = {}; + __u32 len = sizeof(info); + int err; + + skel = struct_ops_arena_autobind__open(); + if (!ASSERT_OK_PTR(skel, "struct_ops_arena_autobind__open")) + return; + /* the other programs need the arena too, and cannot have it */ + bpf_map__set_autocreate(skel->maps.testmod_arena_autobind, false); + bpf_program__set_autoload(skel->progs.trigger, false); + err = bpf_map__set_exclusive_program(skel->maps.arena, skel->progs.unrelated); + if (!ASSERT_OK(err, "set_exclusive_program")) + goto out; + + err = struct_ops_arena_autobind__load(skel); + if (!ASSERT_OK(err, "load")) + goto out; + err = bpf_map_get_info_by_fd(bpf_map__fd(skel->maps.arena), &info, &len); + if (!ASSERT_OK(err, "arena_info")) + goto out; + assert_prog_map(bpf_program__fd(skel->progs.unrelated), info.id, "unrelated"); +out: + struct_ops_arena_autobind__destroy(skel); +} + /* The same through the vmlinux.h rendering of the members, which takes casts. */ static void arena_member_render(void) { @@ -197,6 +311,12 @@ void serial_test_struct_ops_arena(void) /* so that the missing member tests show up as skipped */ test__skip(); } + if (test__start_subtest("arena_autobind")) + arena_autobind(); + if (test__start_subtest("arena_autobind_clone")) + arena_autobind_clone(); + if (test__start_subtest("arena_autobind_excl")) + arena_autobind_excl(); #else test__skip(); #endif diff --git a/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c b/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c new file mode 100644 index 000000000000..495faa0f4a8b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_arena_autobind.c @@ -0,0 +1,64 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ + +#define BPF_NO_KFUNC_PROTOTYPES +#include +#include +#include "bpf_experimental.h" +#include +#include "../test_kmods/bpf_testmod.h" +#include "../test_kmods/bpf_testmod_kfunc.h" + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_ARENA); + __uint(map_flags, BPF_F_MMAPABLE); + __uint(max_entries, 1); +} arena SEC(".maps"); + +/* + * Neither the callback nor the unrelated program refers to the arena. libbpf + * binds it to them all the same, so the callback can use the __arena argument + * the kernel hands it. + */ +SEC("struct_ops/test_arena") +int test_arena_cb(unsigned long long *ctx) +{ + u64 __arena *ptr = (u64 __arena *)ctx[0]; + + *ptr += 1; + return 0; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops3 testmod_arena_autobind = { + .test_arena = (void *)test_arena_cb, +}; + +SEC("syscall") +int unrelated(void *ctx) +{ + return 0; +} + +SEC("syscall") +int trigger(void *ctx) +{ +#if defined(__BPF_FEATURE_ADDR_SPACE_CAST) + u64 __arena *val; + + val = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0); + if (!val) + return 1; + + *val = 41; + if (bpf_testmod_ops3_call_test_arena((u64 *)val)) + return 2; + if (*val != 42) + return 3; + + bpf_arena_free_pages(&arena, (void __arena *)val, 1); +#endif + return 0; +}