Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2024-02-29

We've added 119 non-merge commits during the last 32 day(s) which contain
a total of 150 files changed, 3589 insertions(+), 995 deletions(-).

The main changes are:

1) Extend the BPF verifier to enable static subprog calls in spin lock
   critical sections, from Kumar Kartikeya Dwivedi.

2) Fix confusing and incorrect inference of PTR_TO_CTX argument type
   in BPF global subprogs, from Andrii Nakryiko.

3) Larger batch of riscv BPF JIT improvements and enabling inlining
   of the bpf_kptr_xchg() for RV64, from Pu Lehui.

4) Allow skeleton users to change the values of the fields in struct_ops
   maps at runtime, from Kui-Feng Lee.

5) Extend the verifier's capabilities of tracking scalars when they
   are spilled to stack, especially when the spill or fill is narrowing,
   from Maxim Mikityanskiy & Eduard Zingerman.

6) Various BPF selftest improvements to fix errors under gcc BPF backend,
   from Jose E. Marchesi.

7) Avoid module loading failure when the module trying to register
   a struct_ops has its BTF section stripped, from Geliang Tang.

8) Annotate all kfuncs in .BTF_ids section which eventually allows
   for automatic kfunc prototype generation from bpftool, from Daniel Xu.

9) Several updates to the instruction-set.rst IETF standardization
   document, from Dave Thaler.

10) Shrink the size of struct bpf_map resp. bpf_array,
    from Alexei Starovoitov.

11) Initial small subset of BPF verifier prepwork for sleepable bpf_timer,
    from Benjamin Tissoires.

12) Fix bpftool to be more portable to musl libc by using POSIX's
    basename(), from Arnaldo Carvalho de Melo.

13) Add libbpf support to gcc in CORE macro definitions,
    from Cupertino Miranda.

14) Remove a duplicate type check in perf_event_bpf_event,
    from Florian Lehner.

15) Fix bpf_spin_{un,}lock BPF helpers to actually annotate them
    with notrace correctly, from Yonghong Song.

16) Replace the deprecated bpf_lpm_trie_key 0-length array with flexible
    array to fix build warnings, from Kees Cook.

17) Fix resolve_btfids cross-compilation to non host-native endianness,
    from Viktor Malik.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (119 commits)
  selftests/bpf: Test if shadow types work correctly.
  bpftool: Add an example for struct_ops map and shadow type.
  bpftool: Generated shadow variables for struct_ops maps.
  libbpf: Convert st_ops->data to shadow type.
  libbpf: Set btf_value_type_id of struct bpf_map for struct_ops.
  bpf: Replace bpf_lpm_trie_key 0-length array with flexible array
  bpf, arm64: use bpf_prog_pack for memory management
  arm64: patching: implement text_poke API
  bpf, arm64: support exceptions
  arm64: stacktrace: Implement arch_bpf_stack_walk() for the BPF JIT
  bpf: add is_async_callback_calling_insn() helper
  bpf: introduce in_sleepable() helper
  bpf: allow more maps in sleepable bpf programs
  selftests/bpf: Test case for lacking CFI stub functions.
  bpf: Check cfi_stubs before registering a struct_ops type.
  bpf: Clarify batch lookup/lookup_and_delete semantics
  bpf, docs: specify which BPF_ABS and BPF_IND fields were zero
  bpf, docs: Fix typos in instruction-set.rst
  selftests/bpf: update tcp_custom_syncookie to use scalar packet offset
  bpf: Shrink size of struct bpf_map/bpf_array.
  ...
====================

Link: https://lore.kernel.org/r/20240301001625.8800-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 28 insertions, 5 deletions

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index ec92b87cae01..a17b4c9c4213 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1079,6 +1079,11 @@ struct btf *btf__new(const void *data, __u32 size)
 	return libbpf_ptr(btf_new(data, size, NULL));
 }
 
+struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf)
+{
+	return libbpf_ptr(btf_new(data, size, base_btf));
+}
+
 static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
 				 struct btf_ext **btf_ext)
 {
@@ -3045,12 +3050,16 @@ done:
 	return btf_ext;
 }
 
-const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size)
+const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size)
 {
 	*size = btf_ext->data_size;
 	return btf_ext->data;
 }
 
+__attribute__((alias("btf_ext__raw_data")))
+const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size);
+
+
 struct btf_dedup;
 
 static struct btf_dedup *btf_dedup_new(struct btf *btf, const struct btf_dedup_opts *opts);
@@ -4932,10 +4941,9 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
  */
 struct btf *btf__load_vmlinux_btf(void)
 {
+	const char *sysfs_btf_path = "/sys/kernel/btf/vmlinux";
+	/* fall back locations, trying to find vmlinux on disk */
 	const char *locations[] = {
-		/* try canonical vmlinux BTF through sysfs first */
-		"/sys/kernel/btf/vmlinux",
-		/* fall back to trying to find vmlinux on disk otherwise */
 		"/boot/vmlinux-%1$s",
 		"/lib/modules/%1$s/vmlinux-%1$s",
 		"/lib/modules/%1$s/build/vmlinux",
@@ -4949,8 +4957,23 @@ struct btf *btf__load_vmlinux_btf(void)
 	struct btf *btf;
 	int i, err;
 
-	uname(&buf);
+	/* is canonical sysfs location accessible? */
+	if (faccessat(AT_FDCWD, sysfs_btf_path, F_OK, AT_EACCESS) < 0) {
+		pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enabled?\n",
+			sysfs_btf_path);
+	} else {
+		btf = btf__parse(sysfs_btf_path, NULL);
+		if (!btf) {
+			err = -errno;
+			pr_warn("failed to read kernel BTF from '%s': %d\n", sysfs_btf_path, err);
+			return libbpf_err_ptr(err);
+		}
+		pr_debug("loaded kernel BTF from '%s'\n", path);
+		return btf;
+	}
 
+	/* try fallback locations */
+	uname(&buf);
 	for (i = 0; i < ARRAY_SIZE(locations); i++) {
 		snprintf(path, PATH_MAX, locations[i], buf.release);