- 22 Mar, 2022 3 commits
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Alexei Starovoitov authored
This reverts commit 83acdce6. Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
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Alexei Starovoitov authored
This reverts commit 02752bd9. Signed-off-by:
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Alexei Starovoitov authored
This reverts commit 515a4917. Signed-off-by:
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- 21 Mar, 2022 23 commits
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Yonghong Song authored
Compiled with clang by adding LLVM=1 both kernel and selftests/bpf build, I hit the following compilation error: In file included from /.../tools/testing/selftests/bpf/prog_tests/subskeleton.c:6: ./test_subskeleton_lib.subskel.h:168:6: error: variable 'err' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (!s->progs) ^~~~~~~~~ ./test_subskeleton_lib.subskel.h:181:11: note: uninitialized use occurs here errno = -err; ^~~ ./test_subskeleton_lib.subskel.h:168:2: note: remove the 'if' if its condition is always false if (!s->progs) ^~~~~~~~~~~~~~ The compilation error is triggered by the following code ... int err; obj = (struct test_subskeleton_lib *)calloc(1, sizeof(*obj)); if (!obj) { errno = ENOMEM; goto err; } ... err: test_subskeleton_lib__destroy(obj); errno = -err; ... in test_subskeleton_lib__open(). The 'err' is not initialized, yet it is used in 'errno = -err' later. The fix is to remove 'errno = -err' since errno has been set properly in all incoming branches. Fixes: 00389c58 ("bpftool: Add support for subskeletons") Signed-off-by:Yonghong Song <yhs@fb.com> Signed-off-by:
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Song Liu authored
PMD_SIZE is not available in some special config, e.g. ARCH=arm with CONFIG_MMU=n. Use bpf_prog_pack of PAGE_SIZE in these cases. Fixes: ef078600 ("bpf: Select proper size for bpf_prog_pack") Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Song Liu <song@kernel.org> Signed-off-by:
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Song Liu authored
module_alloc requires num_online_nodes * PMD_SIZE to allocate huge pages. bpf_prog_pack uses pack of size num_online_nodes * PMD_SIZE. OTOH, module_alloc returns addresses that are PMD_SIZE aligned (instead of num_online_nodes * PMD_SIZE aligned). Therefore, PMD_MASK should be used to calculate pack_ptr in bpf_prog_pack_free(). Fixes: ef078600 ("bpf: Select proper size for bpf_prog_pack") Reported-by: syzbot+c946805b5ce6ab87df0b@syzkaller.appspotmail.com Signed-off-by:
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Joanne Koong authored
This fixes the sparse warning reported by the kernel test robot: kernel/bpf/verifier.c:13499:47: sparse: warning: cast from restricted gfp_t kernel/bpf/verifier.c:13501:47: sparse: warning: cast from restricted gfp_t This fix can be verified locally by running: 1) wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O make.cross 2) chmod +x ~/bin/make.cross 3) COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 ./make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' Fixes: b00fa38a ("bpf: Enable non-atomic allocations in local storage") Reported-by:
Joanne Koong <joannelkoong@gmail.com> Signed-off-by:
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Julia Lawall authored
Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by:
Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220318103729.157574-9-Julia.Lawall@inria.fr
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Hengqi Chen authored
pin_fd is dup-ed and assigned in bpf_map__reuse_fd. Close it in bpf_object__reuse_map after reuse. Signed-off-by:
Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by:
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Yafang Shao authored
If there is no btf_id or frozen, it will not show the pids, but the pids don't depend on any one of them. Below is the result after this change: $ ./bpftool map show 2: lpm_trie flags 0x1 key 8B value 8B max_entries 1 memlock 4096B pids systemd(1) 3: lpm_trie flags 0x1 key 20B value 8B max_entries 1 memlock 4096B pids systemd(1) While before this change, the 'pids systemd(1)' can't be displayed. Fixes: 9330986c ("bpf: Add bloom filter map implementation") Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
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Jiri Olsa authored
Andrii reported that backtraces from kprobe_multi program attached as return probes are not complete and showing just initial entry [1]. It's caused by changing registers to have original function ip address as instruction pointer even for return probe, which will screw backtrace from return probe. This change keeps registers intact and store original entry ip and link address on the stack in bpf_kprobe_multi_run_ctx struct, where bpf_get_func_ip and bpf_get_attach_cookie helpers for kprobe_multi programs can find it. [1] https://lore.kernel.org/bpf/CAEf4BzZDDqK24rSKwXNp7XL3ErGD4bZa1M6c_c4EvDSt3jrZcg@mail.gmail.com/T/#m8d1301c0ea0892ddf9dc6fba57a57b8cf11b8c51 Fixes: ca74823c ("bpf: Add cookie support to programs attached with kprobe multi link") Reported-by:
Andrii Nakryiko <andrii@kernel.org> Signed-off-by:
Jiri Olsa <jolsa@kernel.org> Signed-off-by:
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Jiri Olsa authored
This reverts commit 97ee4d20. Following change is adding more complexity to bpf_get_func_ip helper for kprobe_multi programs, which can't be inlined easily. Signed-off-by:
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Yuntao Wang authored
Replace offsetof(hdr_len) + sizeof(hdr_len) with offsetofend(hdr_len) to simplify the check for correctness of btf_data_size in btf_parse_hdr() Signed-off-by:
Yuntao Wang <ytcoode@gmail.com> Signed-off-by:
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Hangbin Liu authored
When test_lirc_mode2_user exec failed, the test report failed but still exit with 0. Fix it by exiting with an error code. Another issue is for the LIRCDEV checking. With bash -n, we need to quote the variable, or it will always be true. So if test_lirc_mode2_user was not run, just exit with skip code. Fixes: 6bdd533c ("bpf: add selftest for lirc_mode2 type program") Signed-off-by:
Hangbin Liu <liuhangbin@gmail.com> Signed-off-by:
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Kumar Kartikeya Dwivedi authored
When CONFIG_DEBUG_INFO_BTF is disabled, bpf_get_btf_vmlinux can return a NULL pointer. Check for it in btf_get_module_btf to prevent a NULL pointer dereference. While kernel test robot only complained about this specific case, let's also check for NULL in other call sites of bpf_get_btf_vmlinux. Fixes: 9492450f ("bpf: Always raise reference in btf_get_module_btf") Reported-by:
kernel test robot <oliver.sang@intel.com> Signed-off-by:
Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
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Namhyung Kim authored
Add a test case for stacktrace with skip > 0 using a small sized buffer. It didn't support skipping entries greater than or equal to the size of buffer and filled the skipped part with 0. Signed-off-by:
Namhyung Kim <namhyung@kernel.org> Signed-off-by:
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Namhyung Kim authored
Let's say that the caller has storage for num_elem stack frames. Then, the BPF stack helper functions walk the stack for only num_elem frames. This means that if skip > 0, one keeps only 'num_elem - skip' frames. This is because it sets init_nr in the perf_callchain_entry to the end of the buffer to save num_elem entries only. I believe it was because the perf callchain code unwound the stack frames until it reached the global max size (sysctl_perf_event_max_stack). However it now has perf_callchain_entry_ctx.max_stack to limit the iteration locally. This simplifies the code to handle init_nr in the BPF callstack entries and removes the confusion with the perf_event's __PERF_SAMPLE_CALLCHAIN_EARLY which sets init_nr to 0. Also change the comment on bpf_get_stack() in the header file to be more explicit what the return value means. Fixes: c195651e ("bpf: add bpf_get_stack helper") Signed-off-by:
Eugene Loh <eugene.loh@oracle.com>
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Song Liu authored
Using HPAGE_PMD_SIZE as the size for bpf_prog_pack is not ideal in some cases. Specifically, for NUMA systems, __vmalloc_node_range requires PMD_SIZE * num_online_nodes() to allocate huge pages. Also, if the system does not support huge pages (i.e., with cmdline option nohugevmalloc), it is better to use PAGE_SIZE packs. Add logic to select proper size for bpf_prog_pack. This solution is not ideal, as it makes assumption about the behavior of module_alloc and __vmalloc_node_range. However, it appears to be the easiest solution as it doesn't require changes in module_alloc and vmalloc code. Fixes: 57631054 ("bpf: Introduce bpf_prog_pack allocator") Signed-off-by:
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Alexei Starovoitov authored
Jakub Sitnicki says: ==================== This patch set is a result of a discussion we had around the RFC patchset from Ilya [1]. The fix for the narrow loads from the RFC series is still relevant, but this series does not depend on it. Nor is it required to unbreak sk_lookup tests on BE, if this series gets applied. To summarize the takeaways from [1]: 1) we want to make 2-byte load from ctx->remote_port portable across LE and BE, 2) we keep the 4-byte load from ctx->remote_port as it is today - result varies on endianess of the platform. [1] https://lore.kernel.org/bpf/20220222182559.2865596-2-iii@linux.ibm.com/ v1 -> v2: - Remove needless check that 4-byte load is from &ctx->remote_port offset (Martin) [v1]: https://lore.kernel.org/bpf/20220317165826.1099418-1-jakub@cloudflare.com/ ==================== Signed-off-by: -
Jakub Sitnicki authored
The context access converter rewrites the 4-byte load from bpf_sk_lookup->remote_port to a 2-byte load from bpf_sk_lookup_kern structure. It means that we cannot treat the destination register contents as a 32-bit value, or the code will not be portable across big- and little-endian architectures. This is exactly the same case as with 4-byte loads from bpf_sock->dst_port so follow the approach outlined in [1] and treat the register contents as a 16-bit value in the test. [1]: https://lore.kernel.org/bpf/20220317113920.1068535-5-jakub@cloudflare.com/ Fixes: 2ed0dc59 ("selftests/bpf: Cover 4-byte load from remote_port in bpf_sk_lookup") Signed-off-by:
Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by:
Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220319183356.233666-4-jakub@cloudflare.com
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Jakub Sitnicki authored
In commit 9a69e2b3 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") ->remote_port field changed from __u32 to __be16. However, narrow load tests which exercise 1-byte sized loads from offsetof(struct bpf_sk_lookup, remote_port) were not adopted to reflect the change. As a result, on little-endian we continue testing loads from addresses: - (__u8 *)&ctx->remote_port + 3 - (__u8 *)&ctx->remote_port + 4 which map to the zero padding following the remote_port field, and don't break the tests because there is no observable change. While on big-endian, we observe breakage because tests expect to see zeros for values loaded from: - (__u8 *)&ctx->remote_port - 1 - (__u8 *)&ctx->remote_port - 2 Above addresses map to ->remote_ip6 field, which precedes ->remote_port, and are populated during the bpf_sk_lookup IPv6 tests. Unsurprisingly, on s390x we observe: #136/38 sk_lookup/narrow access to ctx v4:OK #136/39 sk_lookup/narrow access to ctx v6:FAIL Fix it by removing the checks for 1-byte loads from offsets outside of the ->remote_port field. Fixes: 9a69e2b3 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") Suggested-by:
Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by:
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Jakub Sitnicki authored
In commit 9a69e2b3 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") the remote_port field has been split up and re-declared from u32 to be16. However, the accompanying changes to the context access converter have not been well thought through when it comes big-endian platforms. Today 2-byte wide loads from offsetof(struct bpf_sk_lookup, remote_port) are handled as narrow loads from a 4-byte wide field. This by itself is not enough to create a problem, but when we combine 1. 32-bit wide access to ->remote_port backed by a 16-wide wide load, with 2. inherent difference between litte- and big-endian in how narrow loads need have to be handled (see bpf_ctx_narrow_access_offset), we get inconsistent results for a 2-byte loads from &ctx->remote_port on LE and BE architectures. This in turn makes BPF C code for the common case of 2-byte load from ctx->remote_port not portable. To rectify it, inform the context access converter that remote_port is 2-byte wide field, and only 1-byte loads need to be treated as narrow loads. At the same time, we special-case the 4-byte load from &ctx->remote_port to continue handling it the same way as do today, in order to keep the existing BPF programs working. Fixes: 9a69e2b3 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide") Signed-off-by:
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Alexei Starovoitov authored
Joanne Koong says: ==================== From: Joanne Koong <joannelkoong@gmail.com> Currently, local storage memory can only be allocated atomically (GFP_ATOMIC). This restriction is too strict for sleepable bpf programs. In this patchset, sleepable programs can allocate memory in local storage using GFP_KERNEL, while non-sleepable programs always default to GFP_ATOMIC. v3 <- v2: * Add extra case to local_storage.c selftest to test associating multiple elements with the local storage, which triggers a GFP_KERNEL allocation in local_storage_update(). * Cast gfp_t to __s32 in verifier to fix the sparse warnings v2 <- v1: * Allocate the memory before/after the raw_spin_lock_irqsave, depending on the gfp flags * Rename mem_flags to gfp_flags * Reword the comment "*mem_flags* is set by the bpf verifier" to "*gfp_flags* is a hidden argument provided by the verifier" * Add a sentence to the commit message about existing local storage selftests covering both the GFP_ATOMIC and GFP_KERNEL paths in bpf_local_storage_update. ==================== Signed-off-by: -
Joanne Koong authored
This patch adds a few calls to the existing local storage selftest to test that we can associate multiple elements with the local storage. The sleepable program's call to bpf_sk_storage_get with sk_storage_map2 will lead to an allocation of a new selem under the GFP_KERNEL flag. Signed-off-by:
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Joanne Koong authored
Currently, local storage memory can only be allocated atomically (GFP_ATOMIC). This restriction is too strict for sleepable bpf programs. In this patch, the verifier detects whether the program is sleepable, and passes the corresponding GFP_KERNEL or GFP_ATOMIC flag as a 5th argument to bpf_task/sk/inode_storage_get. This flag will propagate down to the local storage functions that allocate memory. Please note that bpf_task/sk/inode_storage_update_elem functions are invoked by userspace applications through syscalls. Preemption is disabled before bpf_task/sk/inode_storage_update_elem is called, which means they will always have to allocate memory atomically. Signed-off-by:
KP Singh <kpsingh@kernel.org> Acked-by:
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Andrii Nakryiko authored
If BPF object doesn't have an BTF info, don't attempt to search for BTF types describing BPF map key or value layout. Fixes: 262cfb74 ("libbpf: Init btf_{key,value}_type_id on internal map open") Signed-off-by:
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- 19 Mar, 2022 1 commit
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Kumar Kartikeya Dwivedi authored
Align it with helpers like bpf_find_btf_id, so all functions returning BTF in out parameter follow the same rule of raising reference consistently, regardless of module or vmlinux BTF. Adjust existing callers to handle the change accordinly. Signed-off-by:
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- 18 Mar, 2022 13 commits
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Kumar Kartikeya Dwivedi authored
In next few patches, we need a helper that searches all kernel BTFs (vmlinux and module BTFs), and finds the type denoted by 'name' and 'kind'. Turns out bpf_btf_find_by_name_kind already does the same thing, but it instead returns a BTF ID and optionally fd (if module BTF). This is used for relocating ksyms in BPF loader code (bpftool gen skel -L). We extract the core code out into a new helper bpf_find_btf_id, which returns the BTF ID in the return value, and BTF pointer in an out parameter. The reference for the returned BTF pointer is always raised, hence user must either transfer it (e.g. to a fd), or release it after use. Signed-off-by:
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Andrii Nakryiko authored
BPF_TRACE_KPROBE_MULTI is a new attach type name, add it to bpftool's table. This fixes a currently failing CI bpftool check. Signed-off-by:
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Daniel Borkmann authored
Jakub Sitnicki says: ==================== I think we have reached a consensus [1] on how the test for the 4-byte load from bpf_sock->dst_port and bpf_sk_lookup->remote_port should look, so here goes v3. I will submit a separate set of patches for bpf_sk_lookup->remote_port tests. This series has been tested on x86_64 and s390 on top of recent bpf-next - ad13baf4 ("selftests/bpf: Test subprog jit when toggle bpf_jit_harden repeatedly"). [1] https://lore.kernel.org/bpf/87k0cwxkzs.fsf@cloudflare.com/ v2 -> v3: - Split what was previously patch 2 which was doing two things - Use BPF_TCP_* constants (Martin) - Treat the result of 4-byte load from dst_port as a 16-bit value (Martin) - Typo fixup and some rewording in patch 4 description v1 -> v2: - Limit read_sk_dst_port only to client traffic (patch 2) - Make read_sk_dst_port pass on litte- and big-endian (patch 3) v1: https://lore.kernel.org/bpf/20220225184130.483208-1-jakub@cloudflare.com/ v2: https://lore.kernel.org/bpf/20220227202757.519015-1-jakub@cloudflare.com/ ==================== Signed-off-by:
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Jakub Sitnicki authored
The check for 4-byte load from dst_port offset into bpf_sock is failing on big-endian architecture - s390. The bpf access converter rewrites the 4-byte load to a 2-byte load from sock_common at skc_dport offset, as shown below. * s390 / llvm-objdump -S --no-show-raw-insn 00000000000002a0 <sk_dst_port__load_word>: 84: r1 = *(u32 *)(r1 + 48) 85: w0 = 1 86: if w1 == 51966 goto +1 <LBB5_2> 87: w0 = 0 00000000000002c0 <LBB5_2>: 88: exit * s390 / bpftool prog dump xlated _Bool sk_dst_port__load_word(struct bpf_sock * sk): 35: (69) r1 = *(u16 *)(r1 +12) 36: (bc) w1 = w1 37: (b4) w0 = 1 38: (16) if w1 == 0xcafe goto pc+1 39: (b4) w0 = 0 40: (95) exit * x86_64 / llvm-objdump -S --no-show-raw-insn 00000000000002a0 <sk_dst_port__load_word>: 84: r1 = *(u32 *)(r1 + 48) 85: w0 = 1 86: if w1 == 65226 goto +1 <LBB5_2> 87: w0 = 0 00000000000002c0 <LBB5_2>: 88: exit * x86_64 / bpftool prog dump xlated _Bool sk_dst_port__load_word(struct bpf_sock * sk): 33: (69) r1 = *(u16 *)(r1 +12) 34: (b4) w0 = 1 35: (16) if w1 == 0xfeca goto pc+1 36: (b4) w0 = 0 37: (95) exit This leads to surprises if we treat the destination register contents as a 32-bit value, ignoring the fact that in reality it contains a 16-bit value. On little-endian the register contents reflect the bpf_sock struct definition, where the lower 16-bits contain the port number: struct bpf_sock { ... __be16 dst_port; /* offset 48 */ __u16 :16; ... }; However, on big-endian the register contents suggest that field the layout of bpf_sock struct is as so: struct bpf_sock { ... __u16 :16; /* offset 48 */ __be16 dst_port; ... }; Account for this quirky access conversion in the test case exercising the 4-byte load by treating the result as 16-bit wide. Signed-off-by: -
Jakub Sitnicki authored
Replace magic numbers in BPF code with constants from bpf.h, so that they don't require an explanation in the comments. Signed-off-by:
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Jakub Sitnicki authored
cgroup_skb/egress programs which sock_fields test installs process packets flying in both directions, from the client to the server, and in reverse direction. Recently added dst_port check relies on the fact that destination port (remote peer port) of the socket which sends the packet is known ahead of time. This holds true only for the client socket, which connects to the known server port. Filter out any traffic that is not egressing from the client socket in the BPF program that tests reading the dst_port. Fixes: 8f50f16f ("selftests/bpf: Extend verifier and bpf_sock tests for dst_port loads") Signed-off-by:
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Jakub Sitnicki authored
The helper macro that records an error in BPF programs that exercise sock fields access has been inadvertently broken by adaptation work that happened in commit b18c1f0a ("bpf: selftest: Adapt sock_fields test to use skel and global variables"). BPF_NOEXIST flag cannot be used to update BPF_MAP_TYPE_ARRAY. The operation always fails with -EEXIST, which in turn means the error never gets recorded, and the checks for errors always pass. Revert the change in update flags. Fixes: b18c1f0a ("bpf: selftest: Adapt sock_fields test to use skel and global variables") Signed-off-by:
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Andrii Nakryiko authored
Delyan Kratunov says: ==================== In the quest for ever more modularity, a new need has arisen - the ability to access data associated with a BPF library from a corresponding userspace library. The catch is that we don't want the userspace library to know about the structure of the final BPF object that the BPF library is linked into. In pursuit of this modularity, this patch series introduces *subskeletons.* Subskeletons are similar in use and design to skeletons with a couple of differences: 1. The generated storage types do not rely on contiguous storage for the library's variables because they may be interspersed randomly throughout the final BPF object's sections. 2. Subskeletons do not own objects and instead require a loaded bpf_object* to be passed at runtime in order to be initialized. By extension, symbols are resolved at runtime by parsing the final object's BTF. 3. Subskeletons allow access to all global variables, programs, and custom maps. They also expose the internal maps *of the final object*. This allows bpf_var_skeleton objects to contain a bpf_map** instead of a section name. Changes since v3: - Re-add key/value type lookup for legacy user maps (fixing btf test) - Minor cleanups (missed sanitize_identifier call, error messages, formatting) Changes since v2: - Reuse SEC_NAME strict mode flag - Init bpf_map->btf_value_type_id on open for internal maps *and* user BTF maps - Test custom section names (.data.foo) and overlapping kconfig externs between the final object and the library - Minor review comments in gen.c & libbpf.c Changes since v1: - Introduced new strict mode knob for single-routine-in-.text compatibility behavior, which disproportionately affects library objects. bpftool works in 1.0 mode so subskeleton generation doesn't have to worry about this now. - Made bpf_map_btf_value_type_id available earlier and used it wherever applicable. - Refactoring in bpftool gen.c per review comments. - Subskels now use typeof() for array and func proto globals to avoid the need for runtime split btf. - Expanded the subskeleton test to include arrays, custom maps, extern maps, weak symbols, and kconfigs. - selftests/bpf/Makefile now generates a subskel.h for every skel.h it would make. For reference, here is a shortened subskeleton header: #ifndef __TEST_SUBSKELETON_LIB_SUBSKEL_H__ #define __TEST_SUBSKELETON_LIB_SUBSKEL_H__ struct test_subskeleton_lib { struct bpf_object *obj; struct bpf_object_subskeleton *subskel; struct { struct bpf_map *map2; struct bpf_map *map1; struct bpf_map *data; struct bpf_map *rodata; struct bpf_map *bss; struct bpf_map *kconfig; } maps; struct { struct bpf_program *lib_perf_handler; } progs; struct test_subskeleton_lib__data { int *var6; int *var2; int *var5; } data; struct test_subskeleton_lib__rodata { int *var1; } rodata; struct test_subskeleton_lib__bss { struct { int var3_1; __s64 var3_2; } *var3; int *libout1; typeof(int[4]) *var4; typeof(int (*)()) *fn_ptr; } bss; struct test_subskeleton_lib__kconfig { _Bool *CONFIG_BPF_SYSCALL; } kconfig; static inline struct test_subskeleton_lib * test_subskeleton_lib__open(const struct bpf_object *src) { struct test_subskeleton_lib *obj; struct bpf_object_subskeleton *s; int err; ... s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s)); ... s->var_cnt = 9; ... s->vars[0].name = "var6"; s->vars[0].map = &obj->maps.data; s->vars[0].addr = (void**) &obj->data.var6; ... /* maps */ ... /* programs */ s->prog_cnt = 1; ... err = bpf_object__open_subskeleton(s); ... return obj; } #endif /* __TEST_SUBSKELETON_LIB_SUBSKEL_H__ */ ==================== Signed-off-by: -
Delyan Kratunov authored
This patch changes the selftests/bpf Makefile to also generate a subskel.h for every skel.h it would have normally generated. Separately, it also introduces a new subskeleton test which tests library objects, externs, weak symbols, kconfigs, and user maps. Signed-off-by:
Delyan Kratunov <delyank@fb.com> Signed-off-by:
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Delyan Kratunov authored
Subskeletons are headers which require an already loaded program to operate. For example, when a BPF library is linked into a larger BPF object file, the library userspace needs a way to access its own global variables without requiring knowledge about the larger program at build time. As a result, subskeletons require a loaded bpf_object to open(). Further, they find their own symbols in the larger program by walking BTF type data at run time. At this time, programs, maps, and globals are supported through non-owning pointers. Signed-off-by:
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Delyan Kratunov authored
In symmetry with bpf_object__open_skeleton(), bpf_object__open_subskeleton() performs the actual walking and linking of maps, progs, and globals described by bpf_*_skeleton objects. Signed-off-by:
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Delyan Kratunov authored
For internal and user maps, look up the key and value btf types on open() and not load(), so that `bpf_map_btf_value_type_id` is usable in `bpftool gen`. Signed-off-by:
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Delyan Kratunov authored
Currently, libbpf considers a single routine in .text to be a program. This is particularly confusing when it comes to library objects - a single routine meant to be used as an extern will instead be considered a bpf_program. This patch hides this compatibility behavior behind the pre-existing SEC_NAME strict mode flag. Signed-off-by:
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