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-rw-r--r--tools/bpf/bpftool/gen.c13
-rw-r--r--tools/lib/bpf/libbpf.c118
-rw-r--r--tools/lib/bpf/libbpf.h2
3 files changed, 120 insertions, 13 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index a3d72be347b0..4fa4ade1ce74 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -120,6 +120,12 @@ static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz)
static const char *pfxs[] = { ".data", ".rodata", ".bss", ".kconfig" };
int i, n;
+ /* recognize hard coded LLVM section name */
+ if (strcmp(sec_name, ".arena.1") == 0) {
+ /* this is the name to use in skeleton */
+ snprintf(buf, buf_sz, "arena");
+ return true;
+ }
for (i = 0, n = ARRAY_SIZE(pfxs); i < n; i++) {
const char *pfx = pfxs[i];
@@ -250,6 +256,13 @@ static const struct btf_type *find_type_for_map(struct btf *btf, const char *map
static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
{
+ size_t tmp_sz;
+
+ if (bpf_map__type(map) == BPF_MAP_TYPE_ARENA && bpf_map__initial_value(map, &tmp_sz)) {
+ snprintf(buf, sz, "arena");
+ return true;
+ }
+
if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
return false;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 34b722071874..efab29b8935b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -498,6 +498,7 @@ struct bpf_struct_ops {
#define KSYMS_SEC ".ksyms"
#define STRUCT_OPS_SEC ".struct_ops"
#define STRUCT_OPS_LINK_SEC ".struct_ops.link"
+#define ARENA_SEC ".arena.1"
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
@@ -629,6 +630,7 @@ struct elf_state {
Elf *elf;
Elf64_Ehdr *ehdr;
Elf_Data *symbols;
+ Elf_Data *arena_data;
size_t shstrndx; /* section index for section name strings */
size_t strtabidx;
struct elf_sec_desc *secs;
@@ -638,6 +640,7 @@ struct elf_state {
int text_shndx;
int symbols_shndx;
bool has_st_ops;
+ int arena_data_shndx;
};
struct usdt_manager;
@@ -697,6 +700,10 @@ struct bpf_object {
struct usdt_manager *usdt_man;
+ struct bpf_map *arena_map;
+ void *arena_data;
+ size_t arena_data_sz;
+
struct kern_feature_cache *feat_cache;
char *token_path;
int token_fd;
@@ -1443,6 +1450,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
obj->efile.symbols = NULL;
+ obj->efile.arena_data = NULL;
zfree(&obj->efile.secs);
obj->efile.sec_cnt = 0;
@@ -1851,7 +1859,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
def->value_size = data_sz;
def->max_entries = 1;
def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
- ? BPF_F_RDONLY_PROG : 0;
+ ? BPF_F_RDONLY_PROG : 0;
/* failures are fine because of maps like .rodata.str1.1 */
(void) map_fill_btf_type_info(obj, map);
@@ -2843,6 +2851,32 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
return 0;
}
+static int init_arena_map_data(struct bpf_object *obj, struct bpf_map *map,
+ const char *sec_name, int sec_idx,
+ void *data, size_t data_sz)
+{
+ const long page_sz = sysconf(_SC_PAGE_SIZE);
+ size_t mmap_sz;
+
+ mmap_sz = bpf_map_mmap_sz(obj->arena_map);
+ if (roundup(data_sz, page_sz) > mmap_sz) {
+ pr_warn("elf: sec '%s': declared ARENA map size (%zu) is too small to hold global __arena variables of size %zu\n",
+ sec_name, mmap_sz, data_sz);
+ return -E2BIG;
+ }
+
+ obj->arena_data = malloc(data_sz);
+ if (!obj->arena_data)
+ return -ENOMEM;
+ memcpy(obj->arena_data, data, data_sz);
+ obj->arena_data_sz = data_sz;
+
+ /* make bpf_map__init_value() work for ARENA maps */
+ map->mmaped = obj->arena_data;
+
+ return 0;
+}
+
static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
const char *pin_root_path)
{
@@ -2892,6 +2926,33 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
return err;
}
+ for (i = 0; i < obj->nr_maps; i++) {
+ struct bpf_map *map = &obj->maps[i];
+
+ if (map->def.type != BPF_MAP_TYPE_ARENA)
+ continue;
+
+ if (obj->arena_map) {
+ pr_warn("map '%s': only single ARENA map is supported (map '%s' is also ARENA)\n",
+ map->name, obj->arena_map->name);
+ return -EINVAL;
+ }
+ obj->arena_map = map;
+
+ if (obj->efile.arena_data) {
+ err = init_arena_map_data(obj, map, ARENA_SEC, obj->efile.arena_data_shndx,
+ obj->efile.arena_data->d_buf,
+ obj->efile.arena_data->d_size);
+ if (err)
+ return err;
+ }
+ }
+ if (obj->efile.arena_data && !obj->arena_map) {
+ pr_warn("elf: sec '%s': to use global __arena variables the ARENA map should be explicitly declared in SEC(\".maps\")\n",
+ ARENA_SEC);
+ return -ENOENT;
+ }
+
return 0;
}
@@ -3771,6 +3832,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
sec_desc->shdr = sh;
sec_desc->data = data;
obj->efile.has_st_ops = true;
+ } else if (strcmp(name, ARENA_SEC) == 0) {
+ obj->efile.arena_data = data;
+ obj->efile.arena_data_shndx = idx;
} else {
pr_info("elf: skipping unrecognized data section(%d) %s\n",
idx, name);
@@ -4400,6 +4464,15 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
+ /* arena data relocation */
+ if (shdr_idx == obj->efile.arena_data_shndx) {
+ reloc_desc->type = RELO_DATA;
+ reloc_desc->insn_idx = insn_idx;
+ reloc_desc->map_idx = obj->arena_map - obj->maps;
+ reloc_desc->sym_off = sym->st_value;
+ return 0;
+ }
+
/* generic map reference relocation */
if (type == LIBBPF_MAP_UNSPEC) {
if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
@@ -4940,6 +5013,7 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
bpf_gen__map_freeze(obj->gen_loader, map - obj->maps);
return 0;
}
+
err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0);
if (err) {
err = -errno;
@@ -5289,6 +5363,10 @@ retry:
map->name, err);
return err;
}
+ if (obj->arena_data) {
+ memcpy(map->mmaped, obj->arena_data, obj->arena_data_sz);
+ zfree(&obj->arena_data);
+ }
}
if (map->init_slots_sz && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) {
err = init_map_in_map_slots(obj, map);
@@ -8786,13 +8864,9 @@ static void bpf_map__destroy(struct bpf_map *map)
zfree(&map->init_slots);
map->init_slots_sz = 0;
- if (map->mmaped) {
- size_t mmap_sz;
-
- mmap_sz = bpf_map_mmap_sz(map);
- munmap(map->mmaped, mmap_sz);
- map->mmaped = NULL;
- }
+ if (map->mmaped && map->mmaped != map->obj->arena_data)
+ munmap(map->mmaped, bpf_map_mmap_sz(map));
+ map->mmaped = NULL;
if (map->st_ops) {
zfree(&map->st_ops->data);
@@ -8852,6 +8926,8 @@ void bpf_object__close(struct bpf_object *obj)
if (obj->token_fd > 0)
close(obj->token_fd);
+ zfree(&obj->arena_data);
+
free(obj);
}
@@ -10063,18 +10139,26 @@ __u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
int bpf_map__set_initial_value(struct bpf_map *map,
const void *data, size_t size)
{
+ size_t actual_sz;
+
if (map->obj->loaded || map->reused)
return libbpf_err(-EBUSY);
- if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG ||
- size != map->def.value_size)
+ if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG)
+ return libbpf_err(-EINVAL);
+
+ if (map->def.type == BPF_MAP_TYPE_ARENA)
+ actual_sz = map->obj->arena_data_sz;
+ else
+ actual_sz = map->def.value_size;
+ if (size != actual_sz)
return libbpf_err(-EINVAL);
memcpy(map->mmaped, data, size);
return 0;
}
-void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
+void *bpf_map__initial_value(const struct bpf_map *map, size_t *psize)
{
if (bpf_map__is_struct_ops(map)) {
if (psize)
@@ -10084,7 +10168,12 @@ void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
if (!map->mmaped)
return NULL;
- *psize = map->def.value_size;
+
+ if (map->def.type == BPF_MAP_TYPE_ARENA)
+ *psize = map->obj->arena_data_sz;
+ else
+ *psize = map->def.value_size;
+
return map->mmaped;
}
@@ -13573,6 +13662,11 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
continue;
}
+ if (map->def.type == BPF_MAP_TYPE_ARENA) {
+ *mmaped = map->mmaped;
+ continue;
+ }
+
if (map->def.map_flags & BPF_F_RDONLY_PROG)
prot = PROT_READ;
else
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5723cbbfcc41..7b510761f545 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1014,7 +1014,7 @@ LIBBPF_API int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra);
LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
const void *data, size_t size);
-LIBBPF_API void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
+LIBBPF_API void *bpf_map__initial_value(const struct bpf_map *map, size_t *psize);
/**
* @brief **bpf_map__is_internal()** tells the caller whether or not the
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.