| Message ID | 20230307233307.3626875-9-kuifeng@meta.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Transit between BPF TCP congestion controls. | expand |
| Context | Check | Description |
|---|---|---|
| bpf/vmtest-bpf-next-PR | fail | merge-conflict |
| netdev/tree_selection | success | Clearly marked for bpf-next, async |
| netdev/apply | fail | Patch does not apply to bpf-next |
On Tue, Mar 7, 2023 at 3:33 PM Kui-Feng Lee <kuifeng@meta.com> wrote: > > Flags a struct_ops is to back a bpf_link by putting it to the > ".struct_ops.link" section. Once it is flagged, the created > struct_ops can be used to create a bpf_link or update a bpf_link that > has been backed by another struct_ops. > > Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> > --- > tools/lib/bpf/libbpf.c | 64 +++++++++++++++++++++++++++++++++--------- > 1 file changed, 50 insertions(+), 14 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 247de39d136f..d66acd2fdbaa 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -467,6 +467,7 @@ struct bpf_struct_ops { > #define KCONFIG_SEC ".kconfig" > #define KSYMS_SEC ".ksyms" > #define STRUCT_OPS_SEC ".struct_ops" > +#define STRUCT_OPS_LINK_SEC ".struct_ops.link" > > enum libbpf_map_type { > LIBBPF_MAP_UNSPEC, > @@ -596,6 +597,7 @@ struct elf_state { > Elf64_Ehdr *ehdr; > Elf_Data *symbols; > Elf_Data *st_ops_data; > + Elf_Data *st_ops_link_data; > size_t shstrndx; /* section index for section name strings */ > size_t strtabidx; > struct elf_sec_desc *secs; > @@ -605,6 +607,7 @@ struct elf_state { > int text_shndx; > int symbols_shndx; > int st_ops_shndx; > + int st_ops_link_shndx; > }; > > struct usdt_manager; > @@ -1119,7 +1122,7 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) > return 0; > } > > -static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > +static int bpf_object__init_struct_ops_maps_link(struct bpf_object *obj, bool link) let's shorten it and not use double underscores, as this is not a public bpf_object API, just "init_struct_ops_maps" probably is fine > { > const struct btf_type *type, *datasec; > const struct btf_var_secinfo *vsi; > @@ -1127,18 +1130,33 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > const char *tname, *var_name; > __s32 type_id, datasec_id; > const struct btf *btf; > + const char *sec_name; > struct bpf_map *map; > - __u32 i; > + __u32 i, map_flags; > + Elf_Data *data; > + int shndx; > > - if (obj->efile.st_ops_shndx == -1) > + if (link) { > + sec_name = STRUCT_OPS_LINK_SEC; > + shndx = obj->efile.st_ops_link_shndx; > + data = obj->efile.st_ops_link_data; > + map_flags = BPF_F_LINK; > + } else { > + sec_name = STRUCT_OPS_SEC; > + shndx = obj->efile.st_ops_shndx; > + data = obj->efile.st_ops_data; > + map_flags = 0; > + } let's pass these as function arguments instead > + > + if (shndx == -1) > return 0; > > btf = obj->btf; > - datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC, > + datasec_id = btf__find_by_name_kind(btf, sec_name, > BTF_KIND_DATASEC); > if (datasec_id < 0) { > pr_warn("struct_ops init: DATASEC %s not found\n", > - STRUCT_OPS_SEC); > + sec_name); > return -EINVAL; > } > > @@ -1151,7 +1169,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > type_id = btf__resolve_type(obj->btf, vsi->type); > if (type_id < 0) { > pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", > - vsi->type, STRUCT_OPS_SEC); > + vsi->type, sec_name); > return -EINVAL; > } > > @@ -1170,7 +1188,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > if (IS_ERR(map)) > return PTR_ERR(map); > > - map->sec_idx = obj->efile.st_ops_shndx; > + map->sec_idx = shndx; > map->sec_offset = vsi->offset; > map->name = strdup(var_name); > if (!map->name) > @@ -1180,6 +1198,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > map->def.key_size = sizeof(int); > map->def.value_size = type->size; > map->def.max_entries = 1; > + map->def.map_flags = map_flags; > > map->st_ops = calloc(1, sizeof(*map->st_ops)); > if (!map->st_ops) > @@ -1192,14 +1211,14 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) > return -ENOMEM; > > - if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) { > + if (vsi->offset + type->size > data->d_size) { > pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", > - var_name, STRUCT_OPS_SEC); > + var_name, sec_name); > return -EINVAL; > } > > memcpy(st_ops->data, > - obj->efile.st_ops_data->d_buf + vsi->offset, > + data->d_buf + vsi->offset, > type->size); > st_ops->tname = tname; > st_ops->type = type; > @@ -1212,6 +1231,15 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > return 0; > } > > +static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) let's name this bpf_object_init_struct_ops, no double underscores > +{ > + int err; > + > + err = bpf_object__init_struct_ops_maps_link(obj, false); > + err = err ?: bpf_object__init_struct_ops_maps_link(obj, true); > + return err; > +} > + > static struct bpf_object *bpf_object__new(const char *path, > const void *obj_buf, > size_t obj_buf_sz, > @@ -1248,6 +1276,7 @@ static struct bpf_object *bpf_object__new(const char *path, > obj->efile.obj_buf_sz = obj_buf_sz; > obj->efile.btf_maps_shndx = -1; > obj->efile.st_ops_shndx = -1; > + obj->efile.st_ops_link_shndx = -1; > obj->kconfig_map_idx = -1; > > obj->kern_version = get_kernel_version(); > @@ -1265,6 +1294,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj) > obj->efile.elf = NULL; > obj->efile.symbols = NULL; > obj->efile.st_ops_data = NULL; > + obj->efile.st_ops_link_data = NULL; > > zfree(&obj->efile.secs); > obj->efile.sec_cnt = 0; > @@ -2753,12 +2783,13 @@ static bool libbpf_needs_btf(const struct bpf_object *obj) > { > return obj->efile.btf_maps_shndx >= 0 || > obj->efile.st_ops_shndx >= 0 || > + obj->efile.st_ops_link_shndx >= 0 || > obj->nr_extern > 0; > } > > static bool kernel_needs_btf(const struct bpf_object *obj) > { > - return obj->efile.st_ops_shndx >= 0; > + return obj->efile.st_ops_shndx >= 0 || obj->efile.st_ops_link_shndx >= 0; > } > > static int bpf_object__init_btf(struct bpf_object *obj, > @@ -3451,6 +3482,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) > } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { > obj->efile.st_ops_data = data; > obj->efile.st_ops_shndx = idx; > + } else if (strcmp(name, STRUCT_OPS_LINK_SEC) == 0) { > + obj->efile.st_ops_link_data = data; > + obj->efile.st_ops_link_shndx = idx; > } else { > pr_info("elf: skipping unrecognized data section(%d) %s\n", > idx, name); > @@ -3465,6 +3499,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) > /* Only do relo for section with exec instructions */ > if (!section_have_execinstr(obj, targ_sec_idx) && > strcmp(name, ".rel" STRUCT_OPS_SEC) && > + strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) && > strcmp(name, ".rel" MAPS_ELF_SEC)) { > pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", > idx, name, targ_sec_idx, > @@ -6611,7 +6646,7 @@ static int bpf_object__collect_relos(struct bpf_object *obj) > return -LIBBPF_ERRNO__INTERNAL; > } > > - if (idx == obj->efile.st_ops_shndx) > + if (idx == obj->efile.st_ops_shndx || idx == obj->efile.st_ops_link_shndx) > err = bpf_object__collect_st_ops_relos(obj, shdr, data); this function calls find_struct_ops_map_by_offset() which assumes we only have one struct_ops section. This won't work now, please double check all this, there should be no assumption about specific section index > else if (idx == obj->efile.btf_maps_shndx) > err = bpf_object__collect_map_relos(obj, shdr, data); > @@ -8954,8 +8989,9 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, > } > > /* struct_ops BPF prog can be re-used between multiple > - * .struct_ops as long as it's the same struct_ops struct > - * definition and the same function pointer field > + * .struct_ops & .struct_ops.link as long as it's the > + * same struct_ops struct definition and the same > + * function pointer field > */ > if (prog->attach_btf_id != st_ops->type_id || > prog->expected_attach_type != member_idx) { > -- > 2.34.1 >
On 3/7/23 17:07, Andrii Nakryiko wrote: > On Tue, Mar 7, 2023 at 3:33 PM Kui-Feng Lee <kuifeng@meta.com> wrote: >> >> Flags a struct_ops is to back a bpf_link by putting it to the >> ".struct_ops.link" section. Once it is flagged, the created >> struct_ops can be used to create a bpf_link or update a bpf_link that >> has been backed by another struct_ops. >> >> Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> >> --- >> tools/lib/bpf/libbpf.c | 64 +++++++++++++++++++++++++++++++++--------- >> 1 file changed, 50 insertions(+), 14 deletions(-) >> >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c >> index 247de39d136f..d66acd2fdbaa 100644 >> --- a/tools/lib/bpf/libbpf.c >> +++ b/tools/lib/bpf/libbpf.c >> @@ -467,6 +467,7 @@ struct bpf_struct_ops { >> #define KCONFIG_SEC ".kconfig" >> #define KSYMS_SEC ".ksyms" >> #define STRUCT_OPS_SEC ".struct_ops" >> +#define STRUCT_OPS_LINK_SEC ".struct_ops.link" >> >> enum libbpf_map_type { >> LIBBPF_MAP_UNSPEC, >> @@ -596,6 +597,7 @@ struct elf_state { >> Elf64_Ehdr *ehdr; >> Elf_Data *symbols; >> Elf_Data *st_ops_data; >> + Elf_Data *st_ops_link_data; >> size_t shstrndx; /* section index for section name strings */ >> size_t strtabidx; >> struct elf_sec_desc *secs; >> @@ -605,6 +607,7 @@ struct elf_state { >> int text_shndx; >> int symbols_shndx; >> int st_ops_shndx; >> + int st_ops_link_shndx; >> }; >> >> struct usdt_manager; >> @@ -1119,7 +1122,7 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) >> return 0; >> } >> >> -static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> +static int bpf_object__init_struct_ops_maps_link(struct bpf_object *obj, bool link) > > let's shorten it and not use double underscores, as this is not a > public bpf_object API, just "init_struct_ops_maps" probably is fine > >> { >> const struct btf_type *type, *datasec; >> const struct btf_var_secinfo *vsi; >> @@ -1127,18 +1130,33 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> const char *tname, *var_name; >> __s32 type_id, datasec_id; >> const struct btf *btf; >> + const char *sec_name; >> struct bpf_map *map; >> - __u32 i; >> + __u32 i, map_flags; >> + Elf_Data *data; >> + int shndx; >> >> - if (obj->efile.st_ops_shndx == -1) >> + if (link) { >> + sec_name = STRUCT_OPS_LINK_SEC; >> + shndx = obj->efile.st_ops_link_shndx; >> + data = obj->efile.st_ops_link_data; >> + map_flags = BPF_F_LINK; >> + } else { >> + sec_name = STRUCT_OPS_SEC; >> + shndx = obj->efile.st_ops_shndx; >> + data = obj->efile.st_ops_data; >> + map_flags = 0; >> + } > > let's pass these as function arguments instead > >> + >> + if (shndx == -1) >> return 0; >> >> btf = obj->btf; >> - datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC, >> + datasec_id = btf__find_by_name_kind(btf, sec_name, >> BTF_KIND_DATASEC); >> if (datasec_id < 0) { >> pr_warn("struct_ops init: DATASEC %s not found\n", >> - STRUCT_OPS_SEC); >> + sec_name); >> return -EINVAL; >> } >> >> @@ -1151,7 +1169,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> type_id = btf__resolve_type(obj->btf, vsi->type); >> if (type_id < 0) { >> pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", >> - vsi->type, STRUCT_OPS_SEC); >> + vsi->type, sec_name); >> return -EINVAL; >> } >> >> @@ -1170,7 +1188,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> if (IS_ERR(map)) >> return PTR_ERR(map); >> >> - map->sec_idx = obj->efile.st_ops_shndx; >> + map->sec_idx = shndx; >> map->sec_offset = vsi->offset; >> map->name = strdup(var_name); >> if (!map->name) >> @@ -1180,6 +1198,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> map->def.key_size = sizeof(int); >> map->def.value_size = type->size; >> map->def.max_entries = 1; >> + map->def.map_flags = map_flags; >> >> map->st_ops = calloc(1, sizeof(*map->st_ops)); >> if (!map->st_ops) >> @@ -1192,14 +1211,14 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) >> return -ENOMEM; >> >> - if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) { >> + if (vsi->offset + type->size > data->d_size) { >> pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", >> - var_name, STRUCT_OPS_SEC); >> + var_name, sec_name); >> return -EINVAL; >> } >> >> memcpy(st_ops->data, >> - obj->efile.st_ops_data->d_buf + vsi->offset, >> + data->d_buf + vsi->offset, >> type->size); >> st_ops->tname = tname; >> st_ops->type = type; >> @@ -1212,6 +1231,15 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) >> return 0; >> } >> >> +static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) > > let's name this bpf_object_init_struct_ops, no double underscores > >> +{ >> + int err; >> + >> + err = bpf_object__init_struct_ops_maps_link(obj, false); >> + err = err ?: bpf_object__init_struct_ops_maps_link(obj, true); >> + return err; >> +} >> + >> static struct bpf_object *bpf_object__new(const char *path, >> const void *obj_buf, >> size_t obj_buf_sz, >> @@ -1248,6 +1276,7 @@ static struct bpf_object *bpf_object__new(const char *path, >> obj->efile.obj_buf_sz = obj_buf_sz; >> obj->efile.btf_maps_shndx = -1; >> obj->efile.st_ops_shndx = -1; >> + obj->efile.st_ops_link_shndx = -1; >> obj->kconfig_map_idx = -1; >> >> obj->kern_version = get_kernel_version(); >> @@ -1265,6 +1294,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj) >> obj->efile.elf = NULL; >> obj->efile.symbols = NULL; >> obj->efile.st_ops_data = NULL; >> + obj->efile.st_ops_link_data = NULL; >> >> zfree(&obj->efile.secs); >> obj->efile.sec_cnt = 0; >> @@ -2753,12 +2783,13 @@ static bool libbpf_needs_btf(const struct bpf_object *obj) >> { >> return obj->efile.btf_maps_shndx >= 0 || >> obj->efile.st_ops_shndx >= 0 || >> + obj->efile.st_ops_link_shndx >= 0 || >> obj->nr_extern > 0; >> } >> >> static bool kernel_needs_btf(const struct bpf_object *obj) >> { >> - return obj->efile.st_ops_shndx >= 0; >> + return obj->efile.st_ops_shndx >= 0 || obj->efile.st_ops_link_shndx >= 0; >> } >> >> static int bpf_object__init_btf(struct bpf_object *obj, >> @@ -3451,6 +3482,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) >> } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { >> obj->efile.st_ops_data = data; >> obj->efile.st_ops_shndx = idx; >> + } else if (strcmp(name, STRUCT_OPS_LINK_SEC) == 0) { >> + obj->efile.st_ops_link_data = data; >> + obj->efile.st_ops_link_shndx = idx; >> } else { >> pr_info("elf: skipping unrecognized data section(%d) %s\n", >> idx, name); >> @@ -3465,6 +3499,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) >> /* Only do relo for section with exec instructions */ >> if (!section_have_execinstr(obj, targ_sec_idx) && >> strcmp(name, ".rel" STRUCT_OPS_SEC) && >> + strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) && >> strcmp(name, ".rel" MAPS_ELF_SEC)) { >> pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", >> idx, name, targ_sec_idx, >> @@ -6611,7 +6646,7 @@ static int bpf_object__collect_relos(struct bpf_object *obj) >> return -LIBBPF_ERRNO__INTERNAL; >> } >> >> - if (idx == obj->efile.st_ops_shndx) >> + if (idx == obj->efile.st_ops_shndx || idx == obj->efile.st_ops_link_shndx) >> err = bpf_object__collect_st_ops_relos(obj, shdr, data); > > this function calls find_struct_ops_map_by_offset() which assumes we > only have one struct_ops section. This won't work now, please double > check all this, there should be no assumption about specific section > index Yes, I will check the section index of maps. > >> else if (idx == obj->efile.btf_maps_shndx) >> err = bpf_object__collect_map_relos(obj, shdr, data); >> @@ -8954,8 +8989,9 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, >> } >> >> /* struct_ops BPF prog can be re-used between multiple >> - * .struct_ops as long as it's the same struct_ops struct >> - * definition and the same function pointer field >> + * .struct_ops & .struct_ops.link as long as it's the >> + * same struct_ops struct definition and the same >> + * function pointer field >> */ >> if (prog->attach_btf_id != st_ops->type_id || >> prog->expected_attach_type != member_idx) { >> -- >> 2.34.1 >>
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 247de39d136f..d66acd2fdbaa 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -467,6 +467,7 @@ struct bpf_struct_ops { #define KCONFIG_SEC ".kconfig" #define KSYMS_SEC ".ksyms" #define STRUCT_OPS_SEC ".struct_ops" +#define STRUCT_OPS_LINK_SEC ".struct_ops.link" enum libbpf_map_type { LIBBPF_MAP_UNSPEC, @@ -596,6 +597,7 @@ struct elf_state { Elf64_Ehdr *ehdr; Elf_Data *symbols; Elf_Data *st_ops_data; + Elf_Data *st_ops_link_data; size_t shstrndx; /* section index for section name strings */ size_t strtabidx; struct elf_sec_desc *secs; @@ -605,6 +607,7 @@ struct elf_state { int text_shndx; int symbols_shndx; int st_ops_shndx; + int st_ops_link_shndx; }; struct usdt_manager; @@ -1119,7 +1122,7 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) return 0; } -static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) +static int bpf_object__init_struct_ops_maps_link(struct bpf_object *obj, bool link) { const struct btf_type *type, *datasec; const struct btf_var_secinfo *vsi; @@ -1127,18 +1130,33 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) const char *tname, *var_name; __s32 type_id, datasec_id; const struct btf *btf; + const char *sec_name; struct bpf_map *map; - __u32 i; + __u32 i, map_flags; + Elf_Data *data; + int shndx; - if (obj->efile.st_ops_shndx == -1) + if (link) { + sec_name = STRUCT_OPS_LINK_SEC; + shndx = obj->efile.st_ops_link_shndx; + data = obj->efile.st_ops_link_data; + map_flags = BPF_F_LINK; + } else { + sec_name = STRUCT_OPS_SEC; + shndx = obj->efile.st_ops_shndx; + data = obj->efile.st_ops_data; + map_flags = 0; + } + + if (shndx == -1) return 0; btf = obj->btf; - datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC, + datasec_id = btf__find_by_name_kind(btf, sec_name, BTF_KIND_DATASEC); if (datasec_id < 0) { pr_warn("struct_ops init: DATASEC %s not found\n", - STRUCT_OPS_SEC); + sec_name); return -EINVAL; } @@ -1151,7 +1169,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) type_id = btf__resolve_type(obj->btf, vsi->type); if (type_id < 0) { pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", - vsi->type, STRUCT_OPS_SEC); + vsi->type, sec_name); return -EINVAL; } @@ -1170,7 +1188,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) if (IS_ERR(map)) return PTR_ERR(map); - map->sec_idx = obj->efile.st_ops_shndx; + map->sec_idx = shndx; map->sec_offset = vsi->offset; map->name = strdup(var_name); if (!map->name) @@ -1180,6 +1198,7 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) map->def.key_size = sizeof(int); map->def.value_size = type->size; map->def.max_entries = 1; + map->def.map_flags = map_flags; map->st_ops = calloc(1, sizeof(*map->st_ops)); if (!map->st_ops) @@ -1192,14 +1211,14 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) return -ENOMEM; - if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) { + if (vsi->offset + type->size > data->d_size) { pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", - var_name, STRUCT_OPS_SEC); + var_name, sec_name); return -EINVAL; } memcpy(st_ops->data, - obj->efile.st_ops_data->d_buf + vsi->offset, + data->d_buf + vsi->offset, type->size); st_ops->tname = tname; st_ops->type = type; @@ -1212,6 +1231,15 @@ static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) return 0; } +static int bpf_object__init_struct_ops_maps(struct bpf_object *obj) +{ + int err; + + err = bpf_object__init_struct_ops_maps_link(obj, false); + err = err ?: bpf_object__init_struct_ops_maps_link(obj, true); + return err; +} + static struct bpf_object *bpf_object__new(const char *path, const void *obj_buf, size_t obj_buf_sz, @@ -1248,6 +1276,7 @@ static struct bpf_object *bpf_object__new(const char *path, obj->efile.obj_buf_sz = obj_buf_sz; obj->efile.btf_maps_shndx = -1; obj->efile.st_ops_shndx = -1; + obj->efile.st_ops_link_shndx = -1; obj->kconfig_map_idx = -1; obj->kern_version = get_kernel_version(); @@ -1265,6 +1294,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj) obj->efile.elf = NULL; obj->efile.symbols = NULL; obj->efile.st_ops_data = NULL; + obj->efile.st_ops_link_data = NULL; zfree(&obj->efile.secs); obj->efile.sec_cnt = 0; @@ -2753,12 +2783,13 @@ static bool libbpf_needs_btf(const struct bpf_object *obj) { return obj->efile.btf_maps_shndx >= 0 || obj->efile.st_ops_shndx >= 0 || + obj->efile.st_ops_link_shndx >= 0 || obj->nr_extern > 0; } static bool kernel_needs_btf(const struct bpf_object *obj) { - return obj->efile.st_ops_shndx >= 0; + return obj->efile.st_ops_shndx >= 0 || obj->efile.st_ops_link_shndx >= 0; } static int bpf_object__init_btf(struct bpf_object *obj, @@ -3451,6 +3482,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { obj->efile.st_ops_data = data; obj->efile.st_ops_shndx = idx; + } else if (strcmp(name, STRUCT_OPS_LINK_SEC) == 0) { + obj->efile.st_ops_link_data = data; + obj->efile.st_ops_link_shndx = idx; } else { pr_info("elf: skipping unrecognized data section(%d) %s\n", idx, name); @@ -3465,6 +3499,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) /* Only do relo for section with exec instructions */ if (!section_have_execinstr(obj, targ_sec_idx) && strcmp(name, ".rel" STRUCT_OPS_SEC) && + strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", idx, name, targ_sec_idx, @@ -6611,7 +6646,7 @@ static int bpf_object__collect_relos(struct bpf_object *obj) return -LIBBPF_ERRNO__INTERNAL; } - if (idx == obj->efile.st_ops_shndx) + if (idx == obj->efile.st_ops_shndx || idx == obj->efile.st_ops_link_shndx) err = bpf_object__collect_st_ops_relos(obj, shdr, data); else if (idx == obj->efile.btf_maps_shndx) err = bpf_object__collect_map_relos(obj, shdr, data); @@ -8954,8 +8989,9 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, } /* struct_ops BPF prog can be re-used between multiple - * .struct_ops as long as it's the same struct_ops struct - * definition and the same function pointer field + * .struct_ops & .struct_ops.link as long as it's the + * same struct_ops struct definition and the same + * function pointer field */ if (prog->attach_btf_id != st_ops->type_id || prog->expected_attach_type != member_idx) {
Flags a struct_ops is to back a bpf_link by putting it to the ".struct_ops.link" section. Once it is flagged, the created struct_ops can be used to create a bpf_link or update a bpf_link that has been backed by another struct_ops. Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> --- tools/lib/bpf/libbpf.c | 64 +++++++++++++++++++++++++++++++++--------- 1 file changed, 50 insertions(+), 14 deletions(-)