From 0053f7d39d491b6138d7c526876d13885cbb65f1 Mon Sep 17 00:00:00 2001 From: Viktor Malik Date: Wed, 29 Jan 2025 08:18:57 +0100 Subject: [PATCH 01/16] bpftool: Fix readlink usage in get_fd_type The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf) bytes and *does not* append null-terminator to buf. With respect to that, fix two pieces in get_fd_type: 1. Change the truncation check to contain sizeof(buf) rather than sizeof(path). 2. Append null-terminator to buf. Reported by Coverity. Signed-off-by: Viktor Malik Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com Signed-off-by: Alexei Starovoitov --- tools/bpf/bpftool/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index 9b75639434b8..0a764426d935 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -461,10 +461,11 @@ int get_fd_type(int fd) p_err("can't read link type: %s", strerror(errno)); return -1; } - if (n == sizeof(path)) { + if (n == sizeof(buf)) { p_err("can't read link type: path too long!"); return -1; } + buf[n] = '\0'; if (strstr(buf, "bpf-map")) return BPF_OBJ_MAP; -- 2.51.0 From 7e9f3c875d1cae35a3f23dc527d408ea4b90e562 Mon Sep 17 00:00:00 2001 From: "Bastien Curutchet (eBPF Foundation)" Date: Fri, 31 Jan 2025 08:21:45 +0100 Subject: [PATCH 02/16] selftests/bpf: test_xdp_veth: Rename config[] The network topology is held by the config[] table. This 'config' name is a bit too generic if we want to add other configuration variables. Rename config[] to net_config[]. Signed-off-by: Bastien Curutchet (eBPF Foundation) Signed-off-by: Martin KaFai Lau Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250131-redirect-multi-v4-6-970b33678512@bootlin.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_xdp_veth.c | 32 +++++++++---------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c index 710136861bda..a214d5b479be 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -53,7 +53,7 @@ struct veth_configuration { char *remote_addr; /* IP address of the remote veth */ }; -static struct veth_configuration config[VETH_PAIRS_COUNT] = { +static struct veth_configuration net_config[VETH_PAIRS_COUNT] = { { .local_veth = "veth1", .remote_veth = "veth11", @@ -105,17 +105,17 @@ static int attach_programs_to_veth_pair(struct skeletons *skeletons, int index) remote_link = &skeletons->xdp_dummy->links.xdp_dummy_prog; break; } - interface = if_nametoindex(config[index].local_veth); + interface = if_nametoindex(net_config[index].local_veth); if (!ASSERT_NEQ(interface, 0, "non zero interface index")) return -1; link = bpf_program__attach_xdp(local_prog, interface); if (!ASSERT_OK_PTR(link, "attach xdp program to local veth")) return -1; *local_link = link; - nstoken = open_netns(config[index].namespace); + nstoken = open_netns(net_config[index].namespace); if (!ASSERT_OK_PTR(nstoken, "switch to remote veth namespace")) return -1; - interface = if_nametoindex(config[index].remote_veth); + interface = if_nametoindex(net_config[index].remote_veth); if (!ASSERT_NEQ(interface, 0, "non zero interface index")) { close_netns(nstoken); return -1; @@ -135,15 +135,15 @@ static int create_network(void) /* First create and configure all interfaces */ for (i = 0; i < VETH_PAIRS_COUNT; i++) { - SYS(fail, "ip netns add %s", config[i].namespace); + SYS(fail, "ip netns add %s", net_config[i].namespace); SYS(fail, "ip link add %s type veth peer name %s netns %s", - config[i].local_veth, config[i].remote_veth, config[i].namespace); - SYS(fail, "ip link set dev %s up", config[i].local_veth); - if (config[i].remote_addr) - SYS(fail, "ip -n %s addr add %s/24 dev %s", config[i].namespace, - config[i].remote_addr, config[i].remote_veth); - SYS(fail, "ip -n %s link set dev %s up", config[i].namespace, - config[i].remote_veth); + net_config[i].local_veth, net_config[i].remote_veth, net_config[i].namespace); + SYS(fail, "ip link set dev %s up", net_config[i].local_veth); + if (net_config[i].remote_addr) + SYS(fail, "ip -n %s addr add %s/24 dev %s", net_config[i].namespace, + net_config[i].remote_addr, net_config[i].remote_veth); + SYS(fail, "ip -n %s link set dev %s up", net_config[i].namespace, + net_config[i].remote_veth); } return 0; @@ -160,7 +160,7 @@ static void cleanup_network(void) /* Deleting namespaces is enough to automatically remove veth pairs as well */ for (i = 0; i < VETH_PAIRS_COUNT; i++) - SYS_NOFAIL("ip netns del %s", config[i].namespace); + SYS_NOFAIL("ip netns del %s", net_config[i].namespace); } void test_xdp_veth_redirect(void) @@ -190,11 +190,11 @@ void test_xdp_veth_redirect(void) goto destroy_xdp_redirect_map; for (i = 0; i < VETH_PAIRS_COUNT; i++) { - int next_veth = config[i].next_veth; + int next_veth = net_config[i].next_veth; int interface_id; int err; - interface_id = if_nametoindex(config[next_veth].local_veth); + interface_id = if_nametoindex(net_config[next_veth].local_veth); if (!ASSERT_NEQ(interface_id, 0, "non zero interface index")) goto destroy_xdp_redirect_map; err = bpf_map_update_elem(map_fd, &i, &interface_id, BPF_ANY); @@ -208,7 +208,7 @@ void test_xdp_veth_redirect(void) * veth33 from veth11 */ ASSERT_OK(SYS_NOFAIL("ip netns exec %s ping -c 1 -W 1 %s > /dev/null", - config[0].namespace, IP_DST), "ping"); + net_config[0].namespace, IP_DST), "ping"); destroy_xdp_redirect_map: xdp_redirect_map__destroy(skeletons.xdp_redirect_maps); -- 2.51.0 From 12fdd29d5d71d2987a1aec434b704d850a4d7fcb Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Mon, 27 Jan 2025 14:27:19 -0800 Subject: [PATCH 03/16] bpf: Use kallsyms to find the function name of a struct_ops's stub function In commit 1611603537a4 ("bpf: Create argument information for nullable arguments."), it introduced a "__nullable" tagging at the argument name of a stub function. Some background on the commit: it requires to tag the stub function instead of directly tagging the "ops" of a struct. This is because the btf func_proto of the "ops" does not have the argument name and the "__nullable" is tagged at the argument name. To find the stub function of a "ops", it currently relies on a naming convention on the stub function "st_ops__ops_name". e.g. tcp_congestion_ops__ssthresh. However, the new kernel sub system implementing bpf_struct_ops have missed this and have been surprised that the "__nullable" and the to-be-landed "__ref" tagging was not effective. One option would be to give a warning whenever the stub function does not follow the naming convention, regardless if it requires arg tagging or not. Instead, this patch uses the kallsyms_lookup approach and removes the requirement on the naming convention. The st_ops->cfi_stubs has all the stub function kernel addresses. kallsyms_lookup() is used to lookup the function name. With the function name, BTF can be used to find the BTF func_proto. The existing "__nullable" arg name searching logic will then fall through. One notable change is, if it failed in kallsyms_lookup or it failed in looking up the stub function name from the BTF, the bpf_struct_ops registration will fail. This is different from the previous behavior that it silently ignored the "st_ops__ops_name" function not found error. The "tcp_congestion_ops", "sched_ext_ops", and "hid_bpf_ops" can still be registered successfully after this patch. There is struct_ops_maybe_null selftest to cover the "__nullable" tagging. Other minor changes: 1. Removed the "%s__%s" format from the pr_warn because the naming convention is removed. 2. The existing bpf_struct_ops_supported() is also moved earlier because prepare_arg_info needs to use it to decide if the stub function is NULL before calling the prepare_arg_info. Cc: Tejun Heo Cc: Benjamin Tissoires Cc: Yonghong Song Cc: Amery Hung Signed-off-by: Martin KaFai Lau Reviewed-by: Amery Hung Link: https://lore.kernel.org/r/20250127222719.2544255-1-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_struct_ops.c | 98 +++++++++++++++++-------------------- 1 file changed, 44 insertions(+), 54 deletions(-) diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 040fb1cd840b..9b7f3b9c5262 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -146,39 +146,6 @@ void bpf_struct_ops_image_free(void *image) } #define MAYBE_NULL_SUFFIX "__nullable" -#define MAX_STUB_NAME 128 - -/* Return the type info of a stub function, if it exists. - * - * The name of a stub function is made up of the name of the struct_ops and - * the name of the function pointer member, separated by "__". For example, - * if the struct_ops type is named "foo_ops" and the function pointer - * member is named "bar", the stub function name would be "foo_ops__bar". - */ -static const struct btf_type * -find_stub_func_proto(const struct btf *btf, const char *st_op_name, - const char *member_name) -{ - char stub_func_name[MAX_STUB_NAME]; - const struct btf_type *func_type; - s32 btf_id; - int cp; - - cp = snprintf(stub_func_name, MAX_STUB_NAME, "%s__%s", - st_op_name, member_name); - if (cp >= MAX_STUB_NAME) { - pr_warn("Stub function name too long\n"); - return NULL; - } - btf_id = btf_find_by_name_kind(btf, stub_func_name, BTF_KIND_FUNC); - if (btf_id < 0) - return NULL; - func_type = btf_type_by_id(btf, btf_id); - if (!func_type) - return NULL; - - return btf_type_by_id(btf, func_type->type); /* FUNC_PROTO */ -} /* Prepare argument info for every nullable argument of a member of a * struct_ops type. @@ -203,27 +170,42 @@ find_stub_func_proto(const struct btf *btf, const char *st_op_name, static int prepare_arg_info(struct btf *btf, const char *st_ops_name, const char *member_name, - const struct btf_type *func_proto, + const struct btf_type *func_proto, void *stub_func_addr, struct bpf_struct_ops_arg_info *arg_info) { const struct btf_type *stub_func_proto, *pointed_type; const struct btf_param *stub_args, *args; struct bpf_ctx_arg_aux *info, *info_buf; u32 nargs, arg_no, info_cnt = 0; + char ksym[KSYM_SYMBOL_LEN]; + const char *stub_fname; + s32 stub_func_id; u32 arg_btf_id; int offset; - stub_func_proto = find_stub_func_proto(btf, st_ops_name, member_name); - if (!stub_func_proto) - return 0; + stub_fname = kallsyms_lookup((unsigned long)stub_func_addr, NULL, NULL, NULL, ksym); + if (!stub_fname) { + pr_warn("Cannot find the stub function name for the %s in struct %s\n", + member_name, st_ops_name); + return -ENOENT; + } + + stub_func_id = btf_find_by_name_kind(btf, stub_fname, BTF_KIND_FUNC); + if (stub_func_id < 0) { + pr_warn("Cannot find the stub function %s in btf\n", stub_fname); + return -ENOENT; + } + + stub_func_proto = btf_type_by_id(btf, stub_func_id); + stub_func_proto = btf_type_by_id(btf, stub_func_proto->type); /* Check if the number of arguments of the stub function is the same * as the number of arguments of the function pointer. */ nargs = btf_type_vlen(func_proto); if (nargs != btf_type_vlen(stub_func_proto)) { - pr_warn("the number of arguments of the stub function %s__%s does not match the number of arguments of the member %s of struct %s\n", - st_ops_name, member_name, member_name, st_ops_name); + pr_warn("the number of arguments of the stub function %s does not match the number of arguments of the member %s of struct %s\n", + stub_fname, member_name, st_ops_name); return -EINVAL; } @@ -253,21 +235,21 @@ static int prepare_arg_info(struct btf *btf, &arg_btf_id); if (!pointed_type || !btf_type_is_struct(pointed_type)) { - pr_warn("stub function %s__%s has %s tagging to an unsupported type\n", - st_ops_name, member_name, MAYBE_NULL_SUFFIX); + pr_warn("stub function %s has %s tagging to an unsupported type\n", + stub_fname, MAYBE_NULL_SUFFIX); goto err_out; } offset = btf_ctx_arg_offset(btf, func_proto, arg_no); if (offset < 0) { - pr_warn("stub function %s__%s has an invalid trampoline ctx offset for arg#%u\n", - st_ops_name, member_name, arg_no); + pr_warn("stub function %s has an invalid trampoline ctx offset for arg#%u\n", + stub_fname, arg_no); goto err_out; } if (args[arg_no].type != stub_args[arg_no].type) { - pr_warn("arg#%u type in stub function %s__%s does not match with its original func_proto\n", - arg_no, st_ops_name, member_name); + pr_warn("arg#%u type in stub function %s does not match with its original func_proto\n", + arg_no, stub_fname); goto err_out; } @@ -324,6 +306,13 @@ static bool is_module_member(const struct btf *btf, u32 id) return !strcmp(btf_name_by_offset(btf, t->name_off), "module"); } +int bpf_struct_ops_supported(const struct bpf_struct_ops *st_ops, u32 moff) +{ + void *func_ptr = *(void **)(st_ops->cfi_stubs + moff); + + return func_ptr ? 0 : -ENOTSUPP; +} + int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, struct btf *btf, struct bpf_verifier_log *log) @@ -387,7 +376,10 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, for_each_member(i, t, member) { const struct btf_type *func_proto; + void **stub_func_addr; + u32 moff; + moff = __btf_member_bit_offset(t, member) / 8; mname = btf_name_by_offset(btf, member->name_off); if (!*mname) { pr_warn("anon member in struct %s is not supported\n", @@ -413,7 +405,11 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, func_proto = btf_type_resolve_func_ptr(btf, member->type, NULL); - if (!func_proto) + + /* The member is not a function pointer or + * the function pointer is not supported. + */ + if (!func_proto || bpf_struct_ops_supported(st_ops, moff)) continue; if (btf_distill_func_proto(log, btf, @@ -425,8 +421,9 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, goto errout; } + stub_func_addr = *(void **)(st_ops->cfi_stubs + moff); err = prepare_arg_info(btf, st_ops->name, mname, - func_proto, + func_proto, stub_func_addr, arg_info + i); if (err) goto errout; @@ -1152,13 +1149,6 @@ void bpf_struct_ops_put(const void *kdata) bpf_map_put(&st_map->map); } -int bpf_struct_ops_supported(const struct bpf_struct_ops *st_ops, u32 moff) -{ - void *func_ptr = *(void **)(st_ops->cfi_stubs + moff); - - return func_ptr ? 0 : -ENOTSUPP; -} - static bool bpf_struct_ops_valid_to_reg(struct bpf_map *map) { struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map; -- 2.51.0 From edb996fae276927df96c3c332e18a658bc0f2492 Mon Sep 17 00:00:00 2001 From: "Bastien Curutchet (eBPF Foundation)" Date: Fri, 31 Jan 2025 08:21:46 +0100 Subject: [PATCH 04/16] selftests/bpf: test_xdp_veth: Add prog_config[] table The BPF program attached to each veth is hardcoded through the use of the struct skeletons. It prevents from re-using the initialization code in new test cases. Replace the struct skeletons by a bpf_object table. Add a struct prog_configuration that holds the name of BPF program to load on a given veth pair. Use bpf_object__find_program_by_name() / bpf_xdp_attach() API instead of bpf_program__attach_xdp() to retrieve the BPF programs from their names. Detach BPF progs in the cleanup() as it's not automatically done by this API. Signed-off-by: Bastien Curutchet (eBPF Foundation) Signed-off-by: Martin KaFai Lau Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250131-redirect-multi-v4-7-970b33678512@bootlin.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_xdp_veth.c | 133 +++++++++++------- 1 file changed, 80 insertions(+), 53 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c index a214d5b479be..d1435490b967 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -38,12 +38,7 @@ #define VETH_NAME_MAX_LEN 16 #define IP_SRC "10.1.1.11" #define IP_DST "10.1.1.33" - -struct skeletons { - struct xdp_dummy *xdp_dummy; - struct xdp_tx *xdp_tx; - struct xdp_redirect_map *xdp_redirect_maps; -}; +#define PROG_NAME_MAX_LEN 128 struct veth_configuration { char local_veth[VETH_NAME_MAX_LEN]; /* Interface in main namespace */ @@ -77,55 +72,59 @@ static struct veth_configuration net_config[VETH_PAIRS_COUNT] = { } }; -static int attach_programs_to_veth_pair(struct skeletons *skeletons, int index) +struct prog_configuration { + char local_name[PROG_NAME_MAX_LEN]; /* BPF prog to attach to local_veth */ + char remote_name[PROG_NAME_MAX_LEN]; /* BPF prog to attach to remote_veth */ +}; + +static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, + struct prog_configuration *prog, int index) { struct bpf_program *local_prog, *remote_prog; - struct bpf_link **local_link, **remote_link; struct nstoken *nstoken; - struct bpf_link *link; - int interface; - - switch (index) { - case 0: - local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_0; - local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_0; - remote_prog = skeletons->xdp_dummy->progs.xdp_dummy_prog; - remote_link = &skeletons->xdp_dummy->links.xdp_dummy_prog; - break; - case 1: - local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_1; - local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_1; - remote_prog = skeletons->xdp_tx->progs.xdp_tx; - remote_link = &skeletons->xdp_tx->links.xdp_tx; - break; - case 2: - local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_2; - local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_2; - remote_prog = skeletons->xdp_dummy->progs.xdp_dummy_prog; - remote_link = &skeletons->xdp_dummy->links.xdp_dummy_prog; - break; + int interface, ret, i; + + for (i = 0; i < nb_obj; i++) { + local_prog = bpf_object__find_program_by_name(objs[i], prog[index].local_name); + if (local_prog) + break; } + if (!ASSERT_OK_PTR(local_prog, "find local program")) + return -1; + + for (i = 0; i < nb_obj; i++) { + remote_prog = bpf_object__find_program_by_name(objs[i], prog[index].remote_name); + if (remote_prog) + break; + } + if (!ASSERT_OK_PTR(remote_prog, "find remote program")) + return -1; + interface = if_nametoindex(net_config[index].local_veth); if (!ASSERT_NEQ(interface, 0, "non zero interface index")) return -1; - link = bpf_program__attach_xdp(local_prog, interface); - if (!ASSERT_OK_PTR(link, "attach xdp program to local veth")) + + ret = bpf_xdp_attach(interface, bpf_program__fd(local_prog), 0, NULL); + if (!ASSERT_OK(ret, "attach xdp program to local veth")) return -1; - *local_link = link; + nstoken = open_netns(net_config[index].namespace); if (!ASSERT_OK_PTR(nstoken, "switch to remote veth namespace")) return -1; + interface = if_nametoindex(net_config[index].remote_veth); if (!ASSERT_NEQ(interface, 0, "non zero interface index")) { close_netns(nstoken); return -1; } - link = bpf_program__attach_xdp(remote_prog, interface); - *remote_link = link; - close_netns(nstoken); - if (!ASSERT_OK_PTR(link, "attach xdp program to remote veth")) + + ret = bpf_xdp_attach(interface, bpf_program__fd(remote_prog), 0, NULL); + if (!ASSERT_OK(ret, "attach xdp program to remote veth")) { + close_netns(nstoken); return -1; + } + close_netns(nstoken); return 0; } @@ -150,45 +149,73 @@ static int create_network(void) fail: return -1; - } static void cleanup_network(void) { + struct nstoken *nstoken; int i; - /* Deleting namespaces is enough to automatically remove veth pairs as well - */ - for (i = 0; i < VETH_PAIRS_COUNT; i++) + for (i = 0; i < VETH_PAIRS_COUNT; i++) { + bpf_xdp_detach(if_nametoindex(net_config[i].local_veth), 0, NULL); + nstoken = open_netns(net_config[i].namespace); + if (nstoken) { + bpf_xdp_detach(if_nametoindex(net_config[i].remote_veth), 0, NULL); + close_netns(nstoken); + } + /* in case the detach failed */ + SYS_NOFAIL("ip link del %s", net_config[i].local_veth); SYS_NOFAIL("ip netns del %s", net_config[i].namespace); + } } +#define VETH_REDIRECT_SKEL_NB 3 void test_xdp_veth_redirect(void) { - struct skeletons skeletons = {}; + struct prog_configuration ping_config[VETH_PAIRS_COUNT] = { + { + .local_name = "xdp_redirect_map_0", + .remote_name = "xdp_dummy_prog", + }, + { + .local_name = "xdp_redirect_map_1", + .remote_name = "xdp_tx", + }, + { + .local_name = "xdp_redirect_map_2", + .remote_name = "xdp_dummy_prog", + } + }; + struct bpf_object *bpf_objs[VETH_REDIRECT_SKEL_NB]; + struct xdp_redirect_map *xdp_redirect_map; + struct xdp_dummy *xdp_dummy; + struct xdp_tx *xdp_tx; int map_fd; int i; - skeletons.xdp_dummy = xdp_dummy__open_and_load(); - if (!ASSERT_OK_PTR(skeletons.xdp_dummy, "xdp_dummy__open_and_load")) + xdp_dummy = xdp_dummy__open_and_load(); + if (!ASSERT_OK_PTR(xdp_dummy, "xdp_dummy__open_and_load")) return; - skeletons.xdp_tx = xdp_tx__open_and_load(); - if (!ASSERT_OK_PTR(skeletons.xdp_tx, "xdp_tx__open_and_load")) + xdp_tx = xdp_tx__open_and_load(); + if (!ASSERT_OK_PTR(xdp_tx, "xdp_tx__open_and_load")) goto destroy_xdp_dummy; - skeletons.xdp_redirect_maps = xdp_redirect_map__open_and_load(); - if (!ASSERT_OK_PTR(skeletons.xdp_redirect_maps, "xdp_redirect_map__open_and_load")) + xdp_redirect_map = xdp_redirect_map__open_and_load(); + if (!ASSERT_OK_PTR(xdp_redirect_map, "xdp_redirect_map__open_and_load")) goto destroy_xdp_tx; if (!ASSERT_OK(create_network(), "create_network")) goto destroy_xdp_redirect_map; /* Then configure the redirect map and attach programs to interfaces */ - map_fd = bpf_map__fd(skeletons.xdp_redirect_maps->maps.tx_port); + map_fd = bpf_map__fd(xdp_redirect_map->maps.tx_port); if (!ASSERT_OK_FD(map_fd, "open redirect map")) goto destroy_xdp_redirect_map; + bpf_objs[0] = xdp_dummy->obj; + bpf_objs[1] = xdp_tx->obj; + bpf_objs[2] = xdp_redirect_map->obj; for (i = 0; i < VETH_PAIRS_COUNT; i++) { int next_veth = net_config[i].next_veth; int interface_id; @@ -200,7 +227,7 @@ void test_xdp_veth_redirect(void) err = bpf_map_update_elem(map_fd, &i, &interface_id, BPF_ANY); if (!ASSERT_OK(err, "configure interface redirection through map")) goto destroy_xdp_redirect_map; - if (attach_programs_to_veth_pair(&skeletons, i)) + if (attach_programs_to_veth_pair(bpf_objs, VETH_REDIRECT_SKEL_NB, ping_config, i)) goto destroy_xdp_redirect_map; } @@ -211,11 +238,11 @@ void test_xdp_veth_redirect(void) net_config[0].namespace, IP_DST), "ping"); destroy_xdp_redirect_map: - xdp_redirect_map__destroy(skeletons.xdp_redirect_maps); + xdp_redirect_map__destroy(xdp_redirect_map); destroy_xdp_tx: - xdp_tx__destroy(skeletons.xdp_tx); + xdp_tx__destroy(xdp_tx); destroy_xdp_dummy: - xdp_dummy__destroy(skeletons.xdp_dummy); + xdp_dummy__destroy(xdp_dummy); cleanup_network(); } -- 2.51.0 From 450effe2daffb679889f3d57a1309f1efc69202b Mon Sep 17 00:00:00 2001 From: "Bastien Curutchet (eBPF Foundation)" Date: Fri, 31 Jan 2025 08:21:47 +0100 Subject: [PATCH 05/16] selftests/bpf: test_xdp_veth: Add XDP flags to prog_configuration XDP flags are hardcoded to 0 at attachment. Add flags attributes to the struct prog_configuration to allow flag modifications for each test case. Signed-off-by: Bastien Curutchet (eBPF Foundation) Signed-off-by: Martin KaFai Lau Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250131-redirect-multi-v4-8-970b33678512@bootlin.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_xdp_veth.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c index d1435490b967..59fa742b16bd 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -75,6 +75,8 @@ static struct veth_configuration net_config[VETH_PAIRS_COUNT] = { struct prog_configuration { char local_name[PROG_NAME_MAX_LEN]; /* BPF prog to attach to local_veth */ char remote_name[PROG_NAME_MAX_LEN]; /* BPF prog to attach to remote_veth */ + u32 local_flags; /* XDP flags to use on local_veth */ + u32 remote_flags; /* XDP flags to use on remote_veth */ }; static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, @@ -104,7 +106,8 @@ static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, if (!ASSERT_NEQ(interface, 0, "non zero interface index")) return -1; - ret = bpf_xdp_attach(interface, bpf_program__fd(local_prog), 0, NULL); + ret = bpf_xdp_attach(interface, bpf_program__fd(local_prog), + prog[index].local_flags, NULL); if (!ASSERT_OK(ret, "attach xdp program to local veth")) return -1; @@ -118,7 +121,8 @@ static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, return -1; } - ret = bpf_xdp_attach(interface, bpf_program__fd(remote_prog), 0, NULL); + ret = bpf_xdp_attach(interface, bpf_program__fd(remote_prog), + prog[index].remote_flags, NULL); if (!ASSERT_OK(ret, "attach xdp program to remote veth")) { close_netns(nstoken); return -1; @@ -176,14 +180,20 @@ void test_xdp_veth_redirect(void) { .local_name = "xdp_redirect_map_0", .remote_name = "xdp_dummy_prog", + .local_flags = 0, + .remote_flags = 0, }, { .local_name = "xdp_redirect_map_1", .remote_name = "xdp_tx", + .local_flags = 0, + .remote_flags = 0, }, { .local_name = "xdp_redirect_map_2", .remote_name = "xdp_dummy_prog", + .local_flags = 0, + .remote_flags = 0, } }; struct bpf_object *bpf_objs[VETH_REDIRECT_SKEL_NB]; -- 2.51.0 From 29c7bb7d0fa7c4bb30b93c9ea56de80c779fcc47 Mon Sep 17 00:00:00 2001 From: "Bastien Curutchet (eBPF Foundation)" Date: Fri, 31 Jan 2025 08:21:48 +0100 Subject: [PATCH 06/16] selftests/bpf: test_xdp_veth: Use unique names The network namespaces and the veth used by the tests have hardcoded names that can conflict with other tests during parallel runs. Use the append_tid() helper to ensure the uniqueness of these names. Use the static network configuration table as a template on which thread IDs are appended in each test. Set a fixed size to remote_addr field so the struct veth_configuration can also have a fixed size. Signed-off-by: Bastien Curutchet (eBPF Foundation) Signed-off-by: Martin KaFai Lau Link: https://patch.msgid.link/20250131-redirect-multi-v4-9-970b33678512@bootlin.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_xdp_veth.c | 51 ++++++++++++------- 1 file changed, 33 insertions(+), 18 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c index 59fa742b16bd..b869d466ada1 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -35,40 +35,42 @@ #include "xdp_tx.skel.h" #define VETH_PAIRS_COUNT 3 -#define VETH_NAME_MAX_LEN 16 +#define VETH_NAME_MAX_LEN 32 +#define IP_MAX_LEN 16 #define IP_SRC "10.1.1.11" #define IP_DST "10.1.1.33" #define PROG_NAME_MAX_LEN 128 +#define NS_NAME_MAX_LEN 32 struct veth_configuration { char local_veth[VETH_NAME_MAX_LEN]; /* Interface in main namespace */ char remote_veth[VETH_NAME_MAX_LEN]; /* Peer interface in dedicated namespace*/ - const char *namespace; /* Namespace for the remote veth */ + char namespace[NS_NAME_MAX_LEN]; /* Namespace for the remote veth */ int next_veth; /* Local interface to redirect traffic to */ - char *remote_addr; /* IP address of the remote veth */ + char remote_addr[IP_MAX_LEN]; /* IP address of the remote veth */ }; -static struct veth_configuration net_config[VETH_PAIRS_COUNT] = { +static const struct veth_configuration default_config[VETH_PAIRS_COUNT] = { { - .local_veth = "veth1", + .local_veth = "veth1-", .remote_veth = "veth11", .next_veth = 1, .remote_addr = IP_SRC, - .namespace = "ns-veth11" + .namespace = "ns-veth11-" }, { - .local_veth = "veth2", + .local_veth = "veth2-", .remote_veth = "veth22", .next_veth = 2, - .remote_addr = NULL, - .namespace = "ns-veth22" + .remote_addr = "", + .namespace = "ns-veth22-" }, { - .local_veth = "veth3", + .local_veth = "veth3-", .remote_veth = "veth33", .next_veth = 0, .remote_addr = IP_DST, - .namespace = "ns-veth33" + .namespace = "ns-veth33-" } }; @@ -80,6 +82,7 @@ struct prog_configuration { }; static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, + struct veth_configuration *net_config, struct prog_configuration *prog, int index) { struct bpf_program *local_prog, *remote_prog; @@ -132,17 +135,27 @@ static int attach_programs_to_veth_pair(struct bpf_object **objs, size_t nb_obj, return 0; } -static int create_network(void) +static int create_network(struct veth_configuration *net_config) { - int i; + int i, err; + + memcpy(net_config, default_config, VETH_PAIRS_COUNT * sizeof(struct veth_configuration)); /* First create and configure all interfaces */ for (i = 0; i < VETH_PAIRS_COUNT; i++) { + err = append_tid(net_config[i].namespace, NS_NAME_MAX_LEN); + if (!ASSERT_OK(err, "append TID to ns name")) + return -1; + + err = append_tid(net_config[i].local_veth, VETH_NAME_MAX_LEN); + if (!ASSERT_OK(err, "append TID to local veth name")) + return -1; + SYS(fail, "ip netns add %s", net_config[i].namespace); SYS(fail, "ip link add %s type veth peer name %s netns %s", net_config[i].local_veth, net_config[i].remote_veth, net_config[i].namespace); SYS(fail, "ip link set dev %s up", net_config[i].local_veth); - if (net_config[i].remote_addr) + if (net_config[i].remote_addr[0]) SYS(fail, "ip -n %s addr add %s/24 dev %s", net_config[i].namespace, net_config[i].remote_addr, net_config[i].remote_veth); SYS(fail, "ip -n %s link set dev %s up", net_config[i].namespace, @@ -155,7 +168,7 @@ fail: return -1; } -static void cleanup_network(void) +static void cleanup_network(struct veth_configuration *net_config) { struct nstoken *nstoken; int i; @@ -196,6 +209,7 @@ void test_xdp_veth_redirect(void) .remote_flags = 0, } }; + struct veth_configuration net_config[VETH_PAIRS_COUNT]; struct bpf_object *bpf_objs[VETH_REDIRECT_SKEL_NB]; struct xdp_redirect_map *xdp_redirect_map; struct xdp_dummy *xdp_dummy; @@ -215,7 +229,7 @@ void test_xdp_veth_redirect(void) if (!ASSERT_OK_PTR(xdp_redirect_map, "xdp_redirect_map__open_and_load")) goto destroy_xdp_tx; - if (!ASSERT_OK(create_network(), "create_network")) + if (!ASSERT_OK(create_network(net_config), "create network")) goto destroy_xdp_redirect_map; /* Then configure the redirect map and attach programs to interfaces */ @@ -237,7 +251,8 @@ void test_xdp_veth_redirect(void) err = bpf_map_update_elem(map_fd, &i, &interface_id, BPF_ANY); if (!ASSERT_OK(err, "configure interface redirection through map")) goto destroy_xdp_redirect_map; - if (attach_programs_to_veth_pair(bpf_objs, VETH_REDIRECT_SKEL_NB, ping_config, i)) + if (attach_programs_to_veth_pair(bpf_objs, VETH_REDIRECT_SKEL_NB, + net_config, ping_config, i)) goto destroy_xdp_redirect_map; } @@ -254,5 +269,5 @@ destroy_xdp_tx: destroy_xdp_dummy: xdp_dummy__destroy(xdp_dummy); - cleanup_network(); + cleanup_network(net_config); } -- 2.51.0 From 0c4ea7e3479ce92ec4fccf9ae32eddebb8e462f9 Mon Sep 17 00:00:00 2001 From: "Bastien Curutchet (eBPF Foundation)" Date: Fri, 31 Jan 2025 08:21:49 +0100 Subject: [PATCH 07/16] selftests/bpf: test_xdp_veth: Add new test cases for XDP flags The XDP redirection is tested without any flag provided to the xdp_attach() function. Add two subtests that check the correct behaviour with XDP_FLAGS_{DRV/SKB}_MODE flags Signed-off-by: Bastien Curutchet (eBPF Foundation) Signed-off-by: Martin KaFai Lau Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20250131-redirect-multi-v4-10-970b33678512@bootlin.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_xdp_veth.c | 27 ++++++++++++++----- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c index b869d466ada1..73a440e44d52 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -33,6 +33,7 @@ #include "xdp_dummy.skel.h" #include "xdp_redirect_map.skel.h" #include "xdp_tx.skel.h" +#include #define VETH_PAIRS_COUNT 3 #define VETH_NAME_MAX_LEN 32 @@ -187,26 +188,26 @@ static void cleanup_network(struct veth_configuration *net_config) } #define VETH_REDIRECT_SKEL_NB 3 -void test_xdp_veth_redirect(void) +static void xdp_veth_redirect(u32 flags) { struct prog_configuration ping_config[VETH_PAIRS_COUNT] = { { .local_name = "xdp_redirect_map_0", .remote_name = "xdp_dummy_prog", - .local_flags = 0, - .remote_flags = 0, + .local_flags = flags, + .remote_flags = flags, }, { .local_name = "xdp_redirect_map_1", .remote_name = "xdp_tx", - .local_flags = 0, - .remote_flags = 0, + .local_flags = flags, + .remote_flags = flags, }, { .local_name = "xdp_redirect_map_2", .remote_name = "xdp_dummy_prog", - .local_flags = 0, - .remote_flags = 0, + .local_flags = flags, + .remote_flags = flags, } }; struct veth_configuration net_config[VETH_PAIRS_COUNT]; @@ -271,3 +272,15 @@ destroy_xdp_dummy: cleanup_network(net_config); } + +void test_xdp_veth_redirect(void) +{ + if (test__start_subtest("0")) + xdp_veth_redirect(0); + + if (test__start_subtest("DRV_MODE")) + xdp_veth_redirect(XDP_FLAGS_DRV_MODE); + + if (test__start_subtest("SKB_MODE")) + xdp_veth_redirect(XDP_FLAGS_SKB_MODE); +} -- 2.51.0 From 51d1b1d42841c557dabde5b140ae20774591e6dc Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:34 -0800 Subject: [PATCH 08/16] libbpf: Introduce kflag for type_tags and decl_tags in BTF Add the following functions to libbpf API: * btf__add_type_attr() * btf__add_decl_attr() These functions allow to add to BTF the type tags and decl tags with info->kflag set to 1. The kflag indicates that the tag directly encodes an __attribute__ and not a normal tag. See Documentation/bpf/btf.rst changes in the subsequent patch for details on the semantics. Suggested-by: Andrii Nakryiko Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Reviewed-by: Alan Maguire Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250130201239.1429648-2-ihor.solodrai@linux.dev --- tools/lib/bpf/btf.c | 86 +++++++++++++++++++++++++++++----------- tools/lib/bpf/btf.h | 3 ++ tools/lib/bpf/libbpf.map | 2 + 3 files changed, 68 insertions(+), 23 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 560b519f820e..eea99c766a20 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -2090,7 +2090,7 @@ static int validate_type_id(int id) } /* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */ -static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) +static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id, int kflag) { struct btf_type *t; int sz, name_off = 0; @@ -2113,7 +2113,7 @@ static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref } t->name_off = name_off; - t->info = btf_type_info(kind, 0, 0); + t->info = btf_type_info(kind, 0, kflag); t->type = ref_type_id; return btf_commit_type(btf, sz); @@ -2128,7 +2128,7 @@ static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref */ int btf__add_ptr(struct btf *btf, int ref_type_id) { - return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id, 0); } /* @@ -2506,7 +2506,7 @@ int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind) struct btf_type *t; int id; - id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0); + id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0, 0); if (id <= 0) return id; t = btf_type_by_id(btf, id); @@ -2536,7 +2536,7 @@ int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) if (!name || !name[0]) return libbpf_err(-EINVAL); - return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id, 0); } /* @@ -2548,7 +2548,7 @@ int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id) */ int btf__add_volatile(struct btf *btf, int ref_type_id) { - return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id, 0); } /* @@ -2560,7 +2560,7 @@ int btf__add_volatile(struct btf *btf, int ref_type_id) */ int btf__add_const(struct btf *btf, int ref_type_id) { - return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id, 0); } /* @@ -2572,7 +2572,7 @@ int btf__add_const(struct btf *btf, int ref_type_id) */ int btf__add_restrict(struct btf *btf, int ref_type_id) { - return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id, 0); } /* @@ -2588,7 +2588,24 @@ int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id) if (!value || !value[0]) return libbpf_err(-EINVAL); - return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id); + return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id, 0); +} + +/* + * Append new BTF_KIND_TYPE_TAG type with: + * - *value*, non-empty/non-NULL tag value; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * Set info->kflag to 1, indicating this tag is an __attribute__ + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_type_attr(struct btf *btf, const char *value, int ref_type_id) +{ + if (!value || !value[0]) + return libbpf_err(-EINVAL); + + return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id, 1); } /* @@ -2610,7 +2627,7 @@ int btf__add_func(struct btf *btf, const char *name, linkage != BTF_FUNC_EXTERN) return libbpf_err(-EINVAL); - id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id); + id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id, 0); if (id > 0) { struct btf_type *t = btf_type_by_id(btf, id); @@ -2845,18 +2862,8 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __ return 0; } -/* - * Append new BTF_KIND_DECL_TAG type with: - * - *value* - non-empty/non-NULL string; - * - *ref_type_id* - referenced type ID, it might not exist yet; - * - *component_idx* - -1 for tagging reference type, otherwise struct/union - * member or function argument index; - * Returns: - * - >0, type ID of newly added BTF type; - * - <0, on error. - */ -int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, - int component_idx) +static int btf_add_decl_tag(struct btf *btf, const char *value, int ref_type_id, + int component_idx, int kflag) { struct btf_type *t; int sz, value_off; @@ -2880,13 +2887,46 @@ int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, return value_off; t->name_off = value_off; - t->info = btf_type_info(BTF_KIND_DECL_TAG, 0, false); + t->info = btf_type_info(BTF_KIND_DECL_TAG, 0, kflag); t->type = ref_type_id; btf_decl_tag(t)->component_idx = component_idx; return btf_commit_type(btf, sz); } +/* + * Append new BTF_KIND_DECL_TAG type with: + * - *value* - non-empty/non-NULL string; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * - *component_idx* - -1 for tagging reference type, otherwise struct/union + * member or function argument index; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, + int component_idx) +{ + return btf_add_decl_tag(btf, value, ref_type_id, component_idx, 0); +} + +/* + * Append new BTF_KIND_DECL_TAG type with: + * - *value* - non-empty/non-NULL string; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * - *component_idx* - -1 for tagging reference type, otherwise struct/union + * member or function argument index; + * Set info->kflag to 1, indicating this tag is an __attribute__ + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_decl_attr(struct btf *btf, const char *value, int ref_type_id, + int component_idx) +{ + return btf_add_decl_tag(btf, value, ref_type_id, component_idx, 1); +} + struct btf_ext_sec_info_param { __u32 off; __u32 len; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 47ee8f6ac489..4392451d634b 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -227,6 +227,7 @@ LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id); LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id); +LIBBPF_API int btf__add_type_attr(struct btf *btf, const char *value, int ref_type_id); /* func and func_proto construction APIs */ LIBBPF_API int btf__add_func(struct btf *btf, const char *name, @@ -243,6 +244,8 @@ LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, /* tag construction API */ LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, int component_idx); +LIBBPF_API int btf__add_decl_attr(struct btf *btf, const char *value, int ref_type_id, + int component_idx); struct btf_dedup_opts { size_t sz; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index a8b2936a1646..b5a838de6f47 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -436,4 +436,6 @@ LIBBPF_1.6.0 { bpf_linker__add_buf; bpf_linker__add_fd; bpf_linker__new_fd; + btf__add_decl_attr; + btf__add_type_attr; } LIBBPF_1.5.0; -- 2.51.0 From ea70faa1f244ea0bd30f413e4ec7c79a3b5b96f1 Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:35 -0800 Subject: [PATCH 09/16] docs/bpf: Document the semantics of BTF tags with kind_flag Explain the meaning of kind_flag in BTF type_tags and decl_tags. Update uapi btf.h kind_flag comment to reflect the changes. Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250130201239.1429648-3-ihor.solodrai@linux.dev --- Documentation/bpf/btf.rst | 25 +++++++++++++++++++++---- include/uapi/linux/btf.h | 3 ++- tools/include/uapi/linux/btf.h | 3 ++- 3 files changed, 25 insertions(+), 6 deletions(-) diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 2478cef758f8..3b60583f5db2 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -102,7 +102,8 @@ Each type contains the following common data:: * bits 24-28: kind (e.g. int, ptr, array...etc) * bits 29-30: unused * bit 31: kind_flag, currently used by - * struct, union, fwd, enum and enum64. + * struct, union, enum, fwd, enum64, + * decl_tag and type_tag */ __u32 info; /* "size" is used by INT, ENUM, STRUCT, UNION and ENUM64. @@ -478,7 +479,7 @@ No additional type data follow ``btf_type``. ``struct btf_type`` encoding requirement: * ``name_off``: offset to a non-empty string - * ``info.kind_flag``: 0 + * ``info.kind_flag``: 0 or 1 * ``info.kind``: BTF_KIND_DECL_TAG * ``info.vlen``: 0 * ``type``: ``struct``, ``union``, ``func``, ``var`` or ``typedef`` @@ -489,7 +490,6 @@ No additional type data follow ``btf_type``. __u32 component_idx; }; -The ``name_off`` encodes btf_decl_tag attribute string. The ``type`` should be ``struct``, ``union``, ``func``, ``var`` or ``typedef``. For ``var`` or ``typedef`` type, ``btf_decl_tag.component_idx`` must be ``-1``. For the other three types, if the btf_decl_tag attribute is @@ -499,12 +499,21 @@ the attribute is applied to a ``struct``/``union`` member or a ``func`` argument, and ``btf_decl_tag.component_idx`` should be a valid index (starting from 0) pointing to a member or an argument. +If ``info.kind_flag`` is 0, then this is a normal decl tag, and the +``name_off`` encodes btf_decl_tag attribute string. + +If ``info.kind_flag`` is 1, then the decl tag represents an arbitrary +__attribute__. In this case, ``name_off`` encodes a string +representing the attribute-list of the attribute specifier. For +example, for an ``__attribute__((aligned(4)))`` the string's contents +is ``aligned(4)``. + 2.2.18 BTF_KIND_TYPE_TAG ~~~~~~~~~~~~~~~~~~~~~~~~ ``struct btf_type`` encoding requirement: * ``name_off``: offset to a non-empty string - * ``info.kind_flag``: 0 + * ``info.kind_flag``: 0 or 1 * ``info.kind``: BTF_KIND_TYPE_TAG * ``info.vlen``: 0 * ``type``: the type with ``btf_type_tag`` attribute @@ -522,6 +531,14 @@ type_tag, then zero or more const/volatile/restrict/typedef and finally the base type. The base type is one of int, ptr, array, struct, union, enum, func_proto and float types. +Similarly to decl tags, if the ``info.kind_flag`` is 0, then this is a +normal type tag, and the ``name_off`` encodes btf_type_tag attribute +string. + +If ``info.kind_flag`` is 1, then the type tag represents an arbitrary +__attribute__, and the ``name_off`` encodes a string representing the +attribute-list of the attribute specifier. + 2.2.19 BTF_KIND_ENUM64 ~~~~~~~~~~~~~~~~~~~~~~ diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index ec1798b6d3ff..266d4ffa6c07 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -36,7 +36,8 @@ struct btf_type { * bits 24-28: kind (e.g. int, ptr, array...etc) * bits 29-30: unused * bit 31: kind_flag, currently used by - * struct, union, enum, fwd and enum64 + * struct, union, enum, fwd, enum64, + * decl_tag and type_tag */ __u32 info; /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index ec1798b6d3ff..266d4ffa6c07 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -36,7 +36,8 @@ struct btf_type { * bits 24-28: kind (e.g. int, ptr, array...etc) * bits 29-30: unused * bit 31: kind_flag, currently used by - * struct, union, enum, fwd and enum64 + * struct, union, enum, fwd, enum64, + * decl_tag and type_tag */ __u32 info; /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. -- 2.51.0 From 2019c58318b886bb1df523b7a063164943b87785 Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:36 -0800 Subject: [PATCH 10/16] libbpf: Check the kflag of type tags in btf_dump If the kflag is set for a BTF type tag, then the tag represents an arbitrary __attribute__. Change btf_dump accordingly. Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Reviewed-by: Alan Maguire Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250130201239.1429648-4-ihor.solodrai@linux.dev --- tools/lib/bpf/btf_dump.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index a3fc6908f6c9..460c3e57fadb 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -1494,7 +1494,10 @@ static void btf_dump_emit_type_chain(struct btf_dump *d, case BTF_KIND_TYPE_TAG: btf_dump_emit_mods(d, decls); name = btf_name_of(d, t->name_off); - btf_dump_printf(d, " __attribute__((btf_type_tag(\"%s\")))", name); + if (btf_kflag(t)) + btf_dump_printf(d, " __attribute__((%s))", name); + else + btf_dump_printf(d, " __attribute__((btf_type_tag(\"%s\")))", name); break; case BTF_KIND_ARRAY: { const struct btf_array *a = btf_array(t); -- 2.51.0 From 6c2d2a05a762ba3618afa5ed94c11fd8ebc5e435 Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:37 -0800 Subject: [PATCH 11/16] selftests/bpf: Add a btf_dump test for type_tags Factor out common routines handling custom BTF from test_btf_dump_incremental. Then use them in the test_btf_dump_type_tags. test_btf_dump_type_tags verifies that a type tag is dumped correctly with respect to its kflag. Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20250130201239.1429648-5-ihor.solodrai@linux.dev --- .../selftests/bpf/prog_tests/btf_dump.c | 147 +++++++++++++----- 1 file changed, 110 insertions(+), 37 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c index b293b8501fd6..c0a776feec23 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c @@ -126,26 +126,69 @@ done: return err; } -static char *dump_buf; -static size_t dump_buf_sz; -static FILE *dump_buf_file; +struct test_ctx { + struct btf *btf; + struct btf_dump *d; + char *dump_buf; + size_t dump_buf_sz; + FILE *dump_buf_file; +}; -static void test_btf_dump_incremental(void) +static void test_ctx__free(struct test_ctx *t) { - struct btf *btf = NULL; - struct btf_dump *d = NULL; - int id, err, i; + fclose(t->dump_buf_file); + free(t->dump_buf); + btf_dump__free(t->d); + btf__free(t->btf); +} - dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz); - if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream")) - return; - btf = btf__new_empty(); - if (!ASSERT_OK_PTR(btf, "new_empty")) +static int test_ctx__init(struct test_ctx *t) +{ + t->dump_buf_file = open_memstream(&t->dump_buf, &t->dump_buf_sz); + if (!ASSERT_OK_PTR(t->dump_buf_file, "dump_memstream")) + return -1; + t->btf = btf__new_empty(); + if (!ASSERT_OK_PTR(t->btf, "new_empty")) goto err_out; - d = btf_dump__new(btf, btf_dump_printf, dump_buf_file, NULL); - if (!ASSERT_OK(libbpf_get_error(d), "btf_dump__new")) + t->d = btf_dump__new(t->btf, btf_dump_printf, t->dump_buf_file, NULL); + if (!ASSERT_OK(libbpf_get_error(t->d), "btf_dump__new")) goto err_out; + return 0; + +err_out: + test_ctx__free(t); + return -1; +} + +static void test_ctx__dump_and_compare(struct test_ctx *t, + const char *expected_output, + const char *message) +{ + int i, err; + + for (i = 1; i < btf__type_cnt(t->btf); i++) { + err = btf_dump__dump_type(t->d, i); + ASSERT_OK(err, "dump_type_ok"); + } + + fflush(t->dump_buf_file); + t->dump_buf[t->dump_buf_sz] = 0; /* some libc implementations don't do this */ + + ASSERT_STREQ(t->dump_buf, expected_output, message); +} + +static void test_btf_dump_incremental(void) +{ + struct test_ctx t = {}; + struct btf *btf; + int id, err; + + if (test_ctx__init(&t)) + return; + + btf = t.btf; + /* First, generate BTF corresponding to the following C code: * * enum x; @@ -182,15 +225,7 @@ static void test_btf_dump_incremental(void) err = btf__add_field(btf, "x", 4, 0, 0); ASSERT_OK(err, "field_ok"); - for (i = 1; i < btf__type_cnt(btf); i++) { - err = btf_dump__dump_type(d, i); - ASSERT_OK(err, "dump_type_ok"); - } - - fflush(dump_buf_file); - dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */ - - ASSERT_STREQ(dump_buf, + test_ctx__dump_and_compare(&t, "enum x;\n" "\n" "enum x {\n" @@ -221,7 +256,7 @@ static void test_btf_dump_incremental(void) * enum values don't conflict; * */ - fseek(dump_buf_file, 0, SEEK_SET); + fseek(t.dump_buf_file, 0, SEEK_SET); id = btf__add_struct(btf, "s", 4); ASSERT_EQ(id, 7, "struct_id"); @@ -232,14 +267,7 @@ static void test_btf_dump_incremental(void) err = btf__add_field(btf, "s", 6, 64, 0); ASSERT_OK(err, "field_ok"); - for (i = 1; i < btf__type_cnt(btf); i++) { - err = btf_dump__dump_type(d, i); - ASSERT_OK(err, "dump_type_ok"); - } - - fflush(dump_buf_file); - dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */ - ASSERT_STREQ(dump_buf, + test_ctx__dump_and_compare(&t, "struct s___2 {\n" " enum x x;\n" " enum {\n" @@ -248,11 +276,53 @@ static void test_btf_dump_incremental(void) " struct s s;\n" "};\n\n" , "c_dump1"); -err_out: - fclose(dump_buf_file); - free(dump_buf); - btf_dump__free(d); - btf__free(btf); + test_ctx__free(&t); +} + +static void test_btf_dump_type_tags(void) +{ + struct test_ctx t = {}; + struct btf *btf; + int id, err; + + if (test_ctx__init(&t)) + return; + + btf = t.btf; + + /* Generate BTF corresponding to the following C code: + * + * struct s { + * void __attribute__((btf_type_tag(\"void_tag\"))) *p1; + * void __attribute__((void_attr)) *p2; + * }; + * + */ + + id = btf__add_type_tag(btf, "void_tag", 0); + ASSERT_EQ(id, 1, "type_tag_id"); + id = btf__add_ptr(btf, id); + ASSERT_EQ(id, 2, "void_ptr_id1"); + + id = btf__add_type_attr(btf, "void_attr", 0); + ASSERT_EQ(id, 3, "type_attr_id"); + id = btf__add_ptr(btf, id); + ASSERT_EQ(id, 4, "void_ptr_id2"); + + id = btf__add_struct(btf, "s", 8); + ASSERT_EQ(id, 5, "struct_id"); + err = btf__add_field(btf, "p1", 2, 0, 0); + ASSERT_OK(err, "field_ok1"); + err = btf__add_field(btf, "p2", 4, 0, 0); + ASSERT_OK(err, "field_ok2"); + + test_ctx__dump_and_compare(&t, +"struct s {\n" +" void __attribute__((btf_type_tag(\"void_tag\"))) *p1;\n" +" void __attribute__((void_attr)) *p2;\n" +"};\n\n", "dump_and_compare"); + + test_ctx__free(&t); } #define STRSIZE 4096 @@ -874,6 +944,9 @@ void test_btf_dump() { if (test__start_subtest("btf_dump: incremental")) test_btf_dump_incremental(); + if (test__start_subtest("btf_dump: type_tags")) + test_btf_dump_type_tags(); + btf = libbpf_find_kernel_btf(); if (!ASSERT_OK_PTR(btf, "no kernel BTF found")) return; -- 2.51.0 From 53ee0d66d7a6c00358eaffd003cb2c11f6b26e98 Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:38 -0800 Subject: [PATCH 12/16] bpf: Allow kind_flag for BTF type and decl tags BTF type tags and decl tags now may have info->kflag set to 1, changing the semantics of the tag. Change BTF verification to permit BTF that makes use of this feature: * remove kflag check in btf_decl_tag_check_meta(), as both values are valid * allow kflag to be set for BTF_KIND_TYPE_TAG type in btf_ref_type_check_meta() Make sure kind_flag is NOT set when checking for specific BTF tags, such as "kptr", "user" etc. Modify a selftest checking for kflag in decl_tag accordingly. Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20250130201239.1429648-6-ihor.solodrai@linux.dev --- kernel/bpf/btf.c | 26 +++++++++----------- tools/testing/selftests/bpf/prog_tests/btf.c | 4 +-- 2 files changed, 13 insertions(+), 17 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 9de6acddd479..9433b6467bbe 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -2575,7 +2575,7 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env, return -EINVAL; } - if (btf_type_kflag(t)) { + if (btf_type_kflag(t) && !btf_type_is_type_tag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } @@ -3332,6 +3332,8 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, u32 off, int sz, struct btf_field_info *info, u32 field_mask) { enum btf_field_type type; + const char *tag_value; + bool is_type_tag; u32 res_id; /* Permit modifiers on the pointer itself */ @@ -3341,19 +3343,20 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, if (!btf_type_is_ptr(t)) return BTF_FIELD_IGNORE; t = btf_type_by_id(btf, t->type); - - if (!btf_type_is_type_tag(t)) + is_type_tag = btf_type_is_type_tag(t) && !btf_type_kflag(t); + if (!is_type_tag) return BTF_FIELD_IGNORE; /* Reject extra tags */ if (btf_type_is_type_tag(btf_type_by_id(btf, t->type))) return -EINVAL; - if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off))) + tag_value = __btf_name_by_offset(btf, t->name_off); + if (!strcmp("kptr_untrusted", tag_value)) type = BPF_KPTR_UNREF; - else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off))) + else if (!strcmp("kptr", tag_value)) type = BPF_KPTR_REF; - else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off))) + else if (!strcmp("percpu_kptr", tag_value)) type = BPF_KPTR_PERCPU; - else if (!strcmp("uptr", __btf_name_by_offset(btf, t->name_off))) + else if (!strcmp("uptr", tag_value)) type = BPF_UPTR; else return -EINVAL; @@ -4944,11 +4947,6 @@ static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env, return -EINVAL; } - if (btf_type_kflag(t)) { - btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); - return -EINVAL; - } - component_idx = btf_type_decl_tag(t)->component_idx; if (component_idx < -1) { btf_verifier_log_type(env, t, "Invalid component_idx"); @@ -6743,7 +6741,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, info->btf_id = t->type; t = btf_type_by_id(btf, t->type); - if (btf_type_is_type_tag(t)) { + if (btf_type_is_type_tag(t) && !btf_type_kflag(t)) { tag_value = __btf_name_by_offset(btf, t->name_off); if (strcmp(tag_value, "user") == 0) info->reg_type |= MEM_USER; @@ -7002,7 +7000,7 @@ error: /* check type tag */ t = btf_type_by_id(btf, mtype->type); - if (btf_type_is_type_tag(t)) { + if (btf_type_is_type_tag(t) && !btf_type_kflag(t)) { tag_value = __btf_name_by_offset(btf, t->name_off); /* check __user tag */ if (strcmp(tag_value, "user") == 0) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index e63d74ce046f..aab9ad88c845 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -3866,7 +3866,7 @@ static struct btf_raw_test raw_tests[] = { .err_str = "vlen != 0", }, { - .descr = "decl_tag test #8, invalid kflag", + .descr = "decl_tag test #8, tag with kflag", .raw_types = { BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ @@ -3881,8 +3881,6 @@ static struct btf_raw_test raw_tests[] = { .key_type_id = 1, .value_type_id = 1, .max_entries = 1, - .btf_load_err = true, - .err_str = "Invalid btf_info kind_flag", }, { .descr = "decl_tag test #9, var, invalid component_idx", -- 2.51.0 From 770cdcf4a59e58c94116f1da9eb7f46b4b4823cd Mon Sep 17 00:00:00 2001 From: Ihor Solodrai Date: Thu, 30 Jan 2025 12:12:39 -0800 Subject: [PATCH 13/16] selftests/bpf: Add a BTF verification test for kflagged type_tag Add a BTF verification test case for a type_tag with a kflag set. Type tags with a kflag are now valid. Add BTF_DECL_ATTR_ENC and BTF_TYPE_ATTR_ENC test helper macros, corresponding to *_TAG_ENC. Signed-off-by: Ihor Solodrai Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250130201239.1429648-7-ihor.solodrai@linux.dev --- tools/testing/selftests/bpf/prog_tests/btf.c | 19 ++++++++++++++++++- tools/testing/selftests/bpf/test_btf.h | 6 ++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index aab9ad88c845..8a9ba4292109 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -3870,7 +3870,7 @@ static struct btf_raw_test raw_tests[] = { .raw_types = { BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ - BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 1, 0), 2), (-1), + BTF_DECL_ATTR_ENC(NAME_TBD, 2, -1), BTF_END_RAW, }, BTF_STR_SEC("\0local\0tag1"), @@ -4204,6 +4204,23 @@ static struct btf_raw_test raw_tests[] = { .btf_load_err = true, .err_str = "Type tags don't precede modifiers", }, +{ + .descr = "type_tag test #7, tag with kflag", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_TYPE_ATTR_ENC(NAME_TBD, 1), /* [2] */ + BTF_PTR_ENC(2), /* [3] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, +}, { .descr = "enum64 test #1, unsigned, size 8", .raw_types = { diff --git a/tools/testing/selftests/bpf/test_btf.h b/tools/testing/selftests/bpf/test_btf.h index fb4f4714eeb4..e65889ab4adf 100644 --- a/tools/testing/selftests/bpf/test_btf.h +++ b/tools/testing/selftests/bpf/test_btf.h @@ -72,9 +72,15 @@ #define BTF_TYPE_FLOAT_ENC(name, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) +#define BTF_DECL_ATTR_ENC(value, type, component_idx) \ + BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 1, 0), type), (component_idx) + #define BTF_DECL_TAG_ENC(value, type, component_idx) \ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx) +#define BTF_TYPE_ATTR_ENC(value, type) \ + BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 1, 0), type) + #define BTF_TYPE_TAG_ENC(value, type) \ BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type) -- 2.51.0 From 2a9d30fac818ffc97ecfa2f71019181a631b9c9b Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Thu, 30 Jan 2025 15:33:45 -0700 Subject: [PATCH 14/16] selftests/bpf: Support dynamically linking LLVM if static is not available Since 67ab80a01886 ("selftests/bpf: Prefer static linking for LLVM libraries"), only statically linking test_progs is supported. However, some distros only provide a dynamically linkable LLVM. This commit adds a fallback for dynamically linking LLVM if static linking is not available. If both options are available, static linking is chosen. Signed-off-by: Daniel Xu Signed-off-by: Andrii Nakryiko Tested-by: Eduard Zingerman Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/872b64e93de9a6cd6a7a10e6a5c5e7893704f743.1738276344.git.dxu@dxuuu.xyz --- tools/testing/selftests/bpf/Makefile | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 6722080b2107..da514030a153 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -184,9 +184,14 @@ ifeq ($(feature-llvm),1) LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict LLVM_CFLAGS += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags)) - LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS)) - LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS)) - LLVM_LDLIBS += -lstdc++ + # Prefer linking statically if it's available, otherwise fallback to shared + ifeq ($(shell $(LLVM_CONFIG) --link-static --libs &> /dev/null && echo static),static) + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS)) + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS)) + LLVM_LDLIBS += -lstdc++ + else + LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-shared --libs $(LLVM_CONFIG_LIB_COMPONENTS)) + endif LLVM_LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags) endif -- 2.51.0 From 94f53edc64e19640b5245721cd6d0c4a84f52587 Mon Sep 17 00:00:00 2001 From: Jinghao Jia Date: Mon, 3 Feb 2025 02:55:05 -0600 Subject: [PATCH 15/16] samples/bpf: Fix broken vmlinux path for VMLINUX_BTF Commit 13b25489b6f8 ("kbuild: change working directory to external module directory with M=") changed kbuild working directory of bpf sample programs to samples/bpf, which broke the vmlinux path for VMLINUX_BTF, as the Makefiles assume the current work directory to be the kernel output directory and use a relative path (i.e., ./vmlinux): Makefile:316: *** Cannot find a vmlinux for VMLINUX_BTF at any of " /path/to/linux/samples/bpf/vmlinux", build the kernel or set VMLINUX_BTF like "VMLINUX_BTF=/sys/kernel/btf/vmlinux" or VMLINUX_H variable. Stop. Correctly refer to the kernel output directory using $(objtree). Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=") Signed-off-by: Jinghao Jia Signed-off-by: Andrii Nakryiko Tested-by: Ruowen Qin Link: https://lore.kernel.org/bpf/20250203085506.220297-3-jinghao7@illinois.edu --- samples/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index dd9944a97b7e..5b632635e00d 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -307,7 +307,7 @@ $(obj)/$(TRACE_HELPERS): TPROGS_CFLAGS := $(TPROGS_CFLAGS) -D__must_check= VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux)) \ $(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \ - $(abspath ./vmlinux) + $(abspath $(objtree)/vmlinux) VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) $(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) -- 2.51.0 From 0abff462d802a352c87b7f5e71b442b09bf9cfff Mon Sep 17 00:00:00 2001 From: Levi Zim Date: Tue, 4 Feb 2025 10:00:21 +0800 Subject: [PATCH 16/16] bpf: Add comment about helper freeze Put a comment after the bpf helper list in uapi bpf.h to prevent people from trying to add new helpers there and direct them to kfuncs. Suggested-by: Andrii Nakryiko Signed-off-by: Levi Zim Signed-off-by: Andrii Nakryiko Reviewed-by: Bagas Sanjaya Acked-by: Daniel Xu Link: https://lore.kernel.org/bpf/CAEf4BzZvQF+QQ=oip4vdz5A=9bd+OmN-CXk5YARYieaipK9s+A@mail.gmail.com/ Link: https://lore.kernel.org/bpf/20221231004213.h5fx3loccbs5hyzu@macbook-pro-6.dhcp.thefacebook.com/ Link: https://lore.kernel.org/bpf/20250204-bpf-helper-freeze-v1-1-46efd9ff20dc@outlook.com --- include/uapi/linux/bpf.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 2acf9b336371..fff6cdb8d11a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6019,7 +6019,10 @@ union bpf_attr { FN(user_ringbuf_drain, 209, ##ctx) \ FN(cgrp_storage_get, 210, ##ctx) \ FN(cgrp_storage_delete, 211, ##ctx) \ - /* */ + /* This helper list is effectively frozen. If you are trying to \ + * add a new helper, you should add a kfunc instead which has \ + * less stability guarantees. See Documentation/bpf/kfuncs.rst \ + */ /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't * know or care about integer value that is now passed as second argument -- 2.51.0