| Message ID | 20210416202404.3443623-3-andrii@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | BPF static linker: support externs | expand |
On 4/16/21 1:23 PM, Andrii Nakryiko wrote: > Dump succinct information for each member of DATASEC: its kinds and name. This > is extremely helpful to see at a quick glance what is inside each DATASEC of This is indeed very useful and user friendly! > a given BTF. Without this, one has to jump around BTF data to just find out > the name of a VAR or FUNC. DATASEC's var_secinfo member is special in that > regard because it doesn't itself contain the name of the member, delegating > that to the referenced VAR and FUNC kinds. Other kinds, like > STRUCT/UNION/FUNC/ENUM, encode member names directly and thus are clearly > identifiable in BTF dump. > > The new output looks like this: > > [35] DATASEC '.bss' size=0 vlen=6 > type_id=8 offset=0 size=4 (VAR 'input_bss1') > type_id=13 offset=0 size=4 (VAR 'input_bss_weak') > type_id=16 offset=0 size=4 (VAR 'output_bss1') > type_id=17 offset=0 size=4 (VAR 'output_data1') > type_id=18 offset=0 size=4 (VAR 'output_rodata1') > type_id=20 offset=0 size=8 (VAR 'output_sink1') > [36] DATASEC '.data' size=0 vlen=2 > type_id=9 offset=0 size=4 (VAR 'input_data1') > type_id=14 offset=0 size=4 (VAR 'input_data_weak') > [37] DATASEC '.kconfig' size=0 vlen=2 > type_id=25 offset=0 size=4 (VAR 'LINUX_KERNEL_VERSION') > type_id=28 offset=0 size=1 (VAR 'CONFIG_BPF_SYSCALL') > [38] DATASEC '.ksyms' size=0 vlen=1 > type_id=30 offset=0 size=1 (VAR 'bpf_link_fops') > [39] DATASEC '.rodata' size=0 vlen=2 > type_id=12 offset=0 size=4 (VAR 'input_rodata1') > type_id=15 offset=0 size=4 (VAR 'input_rodata_weak') > [40] DATASEC 'license' size=0 vlen=1 > type_id=24 offset=0 size=4 (VAR 'LICENSE') > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com>
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 001749a34899..385d5c955cf3 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -100,26 +100,28 @@ static const char *btf_str(const struct btf *btf, __u32 off) return btf__name_by_offset(btf, off) ? : "(invalid)"; } +static int btf_kind_safe(int kind) +{ + return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; +} + static int dump_btf_type(const struct btf *btf, __u32 id, const struct btf_type *t) { json_writer_t *w = json_wtr; - int kind, safe_kind; - - kind = BTF_INFO_KIND(t->info); - safe_kind = kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; + int kind = btf_kind(t); if (json_output) { jsonw_start_object(w); jsonw_uint_field(w, "id", id); - jsonw_string_field(w, "kind", btf_kind_str[safe_kind]); + jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]); jsonw_string_field(w, "name", btf_str(btf, t->name_off)); } else { - printf("[%u] %s '%s'", id, btf_kind_str[safe_kind], + printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)], btf_str(btf, t->name_off)); } - switch (BTF_INFO_KIND(t->info)) { + switch (kind) { case BTF_KIND_INT: { __u32 v = *(__u32 *)(t + 1); const char *enc; @@ -302,7 +304,8 @@ static int dump_btf_type(const struct btf *btf, __u32 id, break; } case BTF_KIND_DATASEC: { - const struct btf_var_secinfo *v = (const void *)(t+1); + const struct btf_var_secinfo *v = (const void *)(t + 1); + const struct btf_type *vt; __u16 vlen = BTF_INFO_VLEN(t->info); int i; @@ -324,6 +327,13 @@ static int dump_btf_type(const struct btf *btf, __u32 id, } else { printf("\n\ttype_id=%u offset=%u size=%u", v->type, v->offset, v->size); + + if (v->type <= btf__get_nr_types(btf)) { + vt = btf__type_by_id(btf, v->type); + printf(" (%s '%s')", + btf_kind_str[btf_kind_safe(btf_kind(vt))], + btf_str(btf, vt->name_off)); + } } } if (json_output)
Dump succinct information for each member of DATASEC: its kinds and name. This is extremely helpful to see at a quick glance what is inside each DATASEC of a given BTF. Without this, one has to jump around BTF data to just find out the name of a VAR or FUNC. DATASEC's var_secinfo member is special in that regard because it doesn't itself contain the name of the member, delegating that to the referenced VAR and FUNC kinds. Other kinds, like STRUCT/UNION/FUNC/ENUM, encode member names directly and thus are clearly identifiable in BTF dump. The new output looks like this: [35] DATASEC '.bss' size=0 vlen=6 type_id=8 offset=0 size=4 (VAR 'input_bss1') type_id=13 offset=0 size=4 (VAR 'input_bss_weak') type_id=16 offset=0 size=4 (VAR 'output_bss1') type_id=17 offset=0 size=4 (VAR 'output_data1') type_id=18 offset=0 size=4 (VAR 'output_rodata1') type_id=20 offset=0 size=8 (VAR 'output_sink1') [36] DATASEC '.data' size=0 vlen=2 type_id=9 offset=0 size=4 (VAR 'input_data1') type_id=14 offset=0 size=4 (VAR 'input_data_weak') [37] DATASEC '.kconfig' size=0 vlen=2 type_id=25 offset=0 size=4 (VAR 'LINUX_KERNEL_VERSION') type_id=28 offset=0 size=1 (VAR 'CONFIG_BPF_SYSCALL') [38] DATASEC '.ksyms' size=0 vlen=1 type_id=30 offset=0 size=1 (VAR 'bpf_link_fops') [39] DATASEC '.rodata' size=0 vlen=2 type_id=12 offset=0 size=4 (VAR 'input_rodata1') type_id=15 offset=0 size=4 (VAR 'input_rodata_weak') [40] DATASEC 'license' size=0 vlen=1 type_id=24 offset=0 size=4 (VAR 'LICENSE') Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- tools/bpf/bpftool/btf.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)