diff options
| author | Andrii Nakryiko <andriin@fb.com> | 2020-08-19 00:33:56 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-08-19 03:16:15 +0300 |
| commit | 68b08647c7d56ea15114435c3023adc017d11b81 (patch) | |
| tree | c79294afedb4b82d2879dc690a9a4d844cfdaf43 | |
| parent | 70785cfb19287b4b075a266887be5e024bf1206a (diff) | |
| download | linux-68b08647c7d56ea15114435c3023adc017d11b81.tar.xz | |
libbpf: Detect minimal BTF support and skip BTF loading, if missing
Detect whether a kernel supports any BTF at all, and if not, don't even
attempt loading BTF to avoid unnecessary log messages like:
libbpf: Error loading BTF: Invalid argument(22)
libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-8-andriin@fb.com
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e3ab1794d2c3..775fa6317483 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -170,6 +170,8 @@ enum kern_feature_id { FEAT_PROG_NAME, /* v5.2: kernel support for global data sections. */ FEAT_GLOBAL_DATA, + /* BTF support */ + FEAT_BTF, /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ FEAT_BTF_FUNC, /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ @@ -2533,6 +2535,15 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) if (!obj->btf) return 0; + if (!kernel_supports(FEAT_BTF)) { + if (kernel_needs_btf(obj)) { + err = -EOPNOTSUPP; + goto report; + } + pr_debug("Kernel doesn't support BTF, skipping uploading it.\n"); + return 0; + } + sanitize = btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; @@ -2558,6 +2569,7 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) } btf__free(kern_btf); } +report: if (err) { btf_mandatory = kernel_needs_btf(obj); pr_warn("Error loading .BTF into kernel: %d. %s\n", err, @@ -3502,6 +3514,18 @@ static int probe_kern_global_data(void) return probe_fd(ret); } +static int probe_kern_btf(void) +{ + static const char strs[] = "\0int"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + static int probe_kern_btf_func(void) { static const char strs[] = "\0int\0x\0a"; @@ -3633,6 +3657,9 @@ static struct kern_feature_desc { [FEAT_GLOBAL_DATA] = { "global variables", probe_kern_global_data, }, + [FEAT_BTF] = { + "minimal BTF", probe_kern_btf, + }, [FEAT_BTF_FUNC] = { "BTF functions", probe_kern_btf_func, }, |