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-rw-r--r--tools/lib/bpf/libbpf.c260
1 files changed, 140 insertions, 120 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 74f7d9252d13..a7320d272b34 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -462,6 +462,20 @@ struct module_btf {
int fd_array_idx;
};
+enum sec_type {
+ SEC_UNUSED = 0,
+ SEC_RELO,
+ SEC_BSS,
+ SEC_DATA,
+ SEC_RODATA,
+};
+
+struct elf_sec_desc {
+ enum sec_type sec_type;
+ Elf64_Shdr *shdr;
+ Elf_Data *data;
+};
+
struct elf_state {
int fd;
const void *obj_buf;
@@ -469,25 +483,16 @@ struct elf_state {
Elf *elf;
Elf64_Ehdr *ehdr;
Elf_Data *symbols;
- Elf_Data *data;
- Elf_Data *rodata;
- Elf_Data *bss;
Elf_Data *st_ops_data;
size_t shstrndx; /* section index for section name strings */
size_t strtabidx;
- struct {
- Elf64_Shdr *shdr;
- Elf_Data *data;
- } *reloc_sects;
- int nr_reloc_sects;
+ struct elf_sec_desc *secs;
+ int sec_cnt;
int maps_shndx;
int btf_maps_shndx;
__u32 btf_maps_sec_btf_id;
int text_shndx;
int symbols_shndx;
- int data_shndx;
- int rodata_shndx;
- int bss_shndx;
int st_ops_shndx;
};
@@ -506,10 +511,10 @@ struct bpf_object {
struct extern_desc *externs;
int nr_extern;
int kconfig_map_idx;
- int rodata_map_idx;
bool loaded;
bool has_subcalls;
+ bool has_rodata;
struct bpf_gen *gen_loader;
@@ -1168,12 +1173,8 @@ static struct bpf_object *bpf_object__new(const char *path,
obj->efile.obj_buf_sz = obj_buf_sz;
obj->efile.maps_shndx = -1;
obj->efile.btf_maps_shndx = -1;
- obj->efile.data_shndx = -1;
- obj->efile.rodata_shndx = -1;
- obj->efile.bss_shndx = -1;
obj->efile.st_ops_shndx = -1;
obj->kconfig_map_idx = -1;
- obj->rodata_map_idx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
@@ -1193,13 +1194,10 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
obj->efile.elf = NULL;
}
obj->efile.symbols = NULL;
- obj->efile.data = NULL;
- obj->efile.rodata = NULL;
- obj->efile.bss = NULL;
obj->efile.st_ops_data = NULL;
- zfree(&obj->efile.reloc_sects);
- obj->efile.nr_reloc_sects = 0;
+ zfree(&obj->efile.secs);
+ obj->efile.sec_cnt = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
@@ -1340,30 +1338,18 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size)
{
int ret = -ENOENT;
+ Elf_Data *data;
+ Elf_Scn *scn;
*size = 0;
- if (!name) {
+ if (!name)
return -EINVAL;
- } else if (!strcmp(name, DATA_SEC)) {
- if (obj->efile.data)
- *size = obj->efile.data->d_size;
- } else if (!strcmp(name, BSS_SEC)) {
- if (obj->efile.bss)
- *size = obj->efile.bss->d_size;
- } else if (!strcmp(name, RODATA_SEC)) {
- if (obj->efile.rodata)
- *size = obj->efile.rodata->d_size;
- } else if (!strcmp(name, STRUCT_OPS_SEC)) {
- if (obj->efile.st_ops_data)
- *size = obj->efile.st_ops_data->d_size;
- } else {
- Elf_Scn *scn = elf_sec_by_name(obj, name);
- Elf_Data *data = elf_sec_data(obj, scn);
- if (data) {
- ret = 0; /* found it */
- *size = data->d_size;
- }
+ scn = elf_sec_by_name(obj, name);
+ data = elf_sec_data(obj, scn);
+ if (data) {
+ ret = 0; /* found it */
+ *size = data->d_size;
}
return *size ? 0 : ret;
@@ -1516,34 +1502,39 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
static int bpf_object__init_global_data_maps(struct bpf_object *obj)
{
- int err;
+ struct elf_sec_desc *sec_desc;
+ int err = 0, sec_idx;
/*
* Populate obj->maps with libbpf internal maps.
*/
- if (obj->efile.data_shndx >= 0) {
- err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
- obj->efile.data_shndx,
- obj->efile.data->d_buf,
- obj->efile.data->d_size);
- if (err)
- return err;
- }
- if (obj->efile.rodata_shndx >= 0) {
- err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
- obj->efile.rodata_shndx,
- obj->efile.rodata->d_buf,
- obj->efile.rodata->d_size);
- if (err)
- return err;
-
- obj->rodata_map_idx = obj->nr_maps - 1;
- }
- if (obj->efile.bss_shndx >= 0) {
- err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
- obj->efile.bss_shndx,
- NULL,
- obj->efile.bss->d_size);
+ for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) {
+ sec_desc = &obj->efile.secs[sec_idx];
+
+ switch (sec_desc->sec_type) {
+ case SEC_DATA:
+ err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
+ sec_idx,
+ sec_desc->data->d_buf,
+ sec_desc->data->d_size);
+ break;
+ case SEC_RODATA:
+ obj->has_rodata = true;
+ err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
+ sec_idx,
+ sec_desc->data->d_buf,
+ sec_desc->data->d_size);
+ break;
+ case SEC_BSS:
+ err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
+ sec_idx,
+ NULL,
+ sec_desc->data->d_size);
+ break;
+ default:
+ /* skip */
+ break;
+ }
if (err)
return err;
}
@@ -3123,6 +3114,7 @@ static int cmp_progs(const void *_a, const void *_b)
static int bpf_object__elf_collect(struct bpf_object *obj)
{
+ struct elf_sec_desc *sec_desc;
Elf *elf = obj->efile.elf;
Elf_Data *btf_ext_data = NULL;
Elf_Data *btf_data = NULL;
@@ -3132,6 +3124,15 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
Elf_Scn *scn;
Elf64_Shdr *sh;
+ /* ELF section indices are 1-based, so allocate +1 element to keep
+ * indexing simple. Also include 0th invalid section into sec_cnt for
+ * simpler and more traditional iteration logic.
+ */
+ obj->efile.sec_cnt = 1 + obj->efile.ehdr->e_shnum;
+ obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs));
+ if (!obj->efile.secs)
+ return -ENOMEM;
+
/* a bunch of ELF parsing functionality depends on processing symbols,
* so do the first pass and find the symbol table
*/
@@ -3151,8 +3152,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
if (!data)
return -LIBBPF_ERRNO__FORMAT;
+ idx = elf_ndxscn(scn);
+
obj->efile.symbols = data;
- obj->efile.symbols_shndx = elf_ndxscn(scn);
+ obj->efile.symbols_shndx = idx;
obj->efile.strtabidx = sh->sh_link;
}
}
@@ -3165,7 +3168,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
scn = NULL;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
- idx++;
+ idx = elf_ndxscn(scn);
+ sec_desc = &obj->efile.secs[idx];
sh = elf_sec_hdr(obj, scn);
if (!sh)
@@ -3213,11 +3217,13 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
if (err)
return err;
} else if (strcmp(name, DATA_SEC) == 0) {
- obj->efile.data = data;
- obj->efile.data_shndx = idx;
+ sec_desc->sec_type = SEC_DATA;
+ sec_desc->shdr = sh;
+ sec_desc->data = data;
} else if (strcmp(name, RODATA_SEC) == 0) {
- obj->efile.rodata = data;
- obj->efile.rodata_shndx = idx;
+ sec_desc->sec_type = SEC_RODATA;
+ sec_desc->shdr = sh;
+ sec_desc->data = data;
} else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
obj->efile.st_ops_data = data;
obj->efile.st_ops_shndx = idx;
@@ -3226,33 +3232,25 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
idx, name);
}
} else if (sh->sh_type == SHT_REL) {
- int nr_sects = obj->efile.nr_reloc_sects;
- void *sects = obj->efile.reloc_sects;
- int sec = sh->sh_info; /* points to other section */
+ int targ_sec_idx = sh->sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
- if (!section_have_execinstr(obj, sec) &&
+ if (!section_have_execinstr(obj, targ_sec_idx) &&
strcmp(name, ".rel" STRUCT_OPS_SEC) &&
strcmp(name, ".rel" MAPS_ELF_SEC)) {
pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n",
- idx, name, sec,
- elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>");
+ idx, name, targ_sec_idx,
+ elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>");
continue;
}
- sects = libbpf_reallocarray(sects, nr_sects + 1,
- sizeof(*obj->efile.reloc_sects));
- if (!sects)
- return -ENOMEM;
-
- obj->efile.reloc_sects = sects;
- obj->efile.nr_reloc_sects++;
-
- obj->efile.reloc_sects[nr_sects].shdr = sh;
- obj->efile.reloc_sects[nr_sects].data = data;
+ sec_desc->sec_type = SEC_RELO;
+ sec_desc->shdr = sh;
+ sec_desc->data = data;
} else if (sh->sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) {
- obj->efile.bss = data;
- obj->efile.bss_shndx = idx;
+ sec_desc->sec_type = SEC_BSS;
+ sec_desc->shdr = sh;
+ sec_desc->data = data;
} else {
pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name,
(size_t)sh->sh_size);
@@ -3732,9 +3730,14 @@ bpf_object__find_program_by_name(const struct bpf_object *obj,
static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
int shndx)
{
- return shndx == obj->efile.data_shndx ||
- shndx == obj->efile.bss_shndx ||
- shndx == obj->efile.rodata_shndx;
+ switch (obj->efile.secs[shndx].sec_type) {
+ case SEC_BSS:
+ case SEC_DATA:
+ case SEC_RODATA:
+ return true;
+ default:
+ return false;
+ }
}
static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
@@ -3747,16 +3750,19 @@ static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
{
- if (shndx == obj->efile.data_shndx)
- return LIBBPF_MAP_DATA;
- else if (shndx == obj->efile.bss_shndx)
+ if (shndx == obj->efile.symbols_shndx)
+ return LIBBPF_MAP_KCONFIG;
+
+ switch (obj->efile.secs[shndx].sec_type) {
+ case SEC_BSS:
return LIBBPF_MAP_BSS;
- else if (shndx == obj->efile.rodata_shndx)
+ case SEC_DATA:
+ return LIBBPF_MAP_DATA;
+ case SEC_RODATA:
return LIBBPF_MAP_RODATA;
- else if (shndx == obj->efile.symbols_shndx)
- return LIBBPF_MAP_KCONFIG;
- else
+ default:
return LIBBPF_MAP_UNSPEC;
+ }
}
static int bpf_program__record_reloc(struct bpf_program *prog,
@@ -3892,7 +3898,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
map = &obj->maps[map_idx];
- if (map->libbpf_type != type)
+ if (map->libbpf_type != type || map->sec_idx != sym->st_shndx)
continue;
pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n",
prog->name, map_idx, map->name, map->sec_idx,
@@ -6205,10 +6211,18 @@ static int bpf_object__collect_relos(struct bpf_object *obj)
{
int i, err;
- for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
- Elf64_Shdr *shdr = obj->efile.reloc_sects[i].shdr;
- Elf_Data *data = obj->efile.reloc_sects[i].data;
- int idx = shdr->sh_info;
+ for (i = 0; i < obj->efile.sec_cnt; i++) {
+ struct elf_sec_desc *sec_desc = &obj->efile.secs[i];
+ Elf64_Shdr *shdr;
+ Elf_Data *data;
+ int idx;
+
+ if (sec_desc->sec_type != SEC_RELO)
+ continue;
+
+ shdr = sec_desc->shdr;
+ data = sec_desc->data;
+ idx = shdr->sh_info;
if (shdr->sh_type != SHT_REL) {
pr_warn("internal error at %d\n", __LINE__);
@@ -6331,6 +6345,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *license, __u32 kern_version, int *pfd)
{
struct bpf_prog_load_params load_attr = {};
+ struct bpf_object *obj = prog->obj;
char *cp, errmsg[STRERR_BUFSIZE];
size_t log_buf_size = 0;
char *log_buf = NULL;
@@ -6351,7 +6366,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.prog_type = prog->type;
load_attr.expected_attach_type = prog->expected_attach_type;
- if (kernel_supports(prog->obj, FEAT_PROG_NAME))
+ if (kernel_supports(obj, FEAT_PROG_NAME))
load_attr.name = prog->name;
load_attr.insns = insns;
load_attr.insn_cnt = insns_cnt;
@@ -6364,8 +6379,8 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.prog_ifindex = prog->prog_ifindex;
/* specify func_info/line_info only if kernel supports them */
- btf_fd = bpf_object__btf_fd(prog->obj);
- if (btf_fd >= 0 && kernel_supports(prog->obj, FEAT_BTF_FUNC)) {
+ btf_fd = bpf_object__btf_fd(obj);
+ if (btf_fd >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) {
load_attr.prog_btf_fd = btf_fd;
load_attr.func_info = prog->func_info;
load_attr.func_info_rec_size = prog->func_info_rec_size;
@@ -6376,7 +6391,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
}
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
- load_attr.fd_array = prog->obj->fd_array;
+ load_attr.fd_array = obj->fd_array;
/* adjust load_attr if sec_def provides custom preload callback */
if (prog->sec_def && prog->sec_def->preload_fn) {
@@ -6388,9 +6403,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
}
}
- if (prog->obj->gen_loader) {
- bpf_gen__prog_load(prog->obj->gen_loader, &load_attr,
- prog - prog->obj->programs);
+ if (obj->gen_loader) {
+ bpf_gen__prog_load(obj->gen_loader, &load_attr,
+ prog - obj->programs);
*pfd = -1;
return 0;
}
@@ -6411,16 +6426,21 @@ retry_load:
if (log_buf && load_attr.log_level)
pr_debug("verifier log:\n%s", log_buf);
- if (prog->obj->rodata_map_idx >= 0 &&
- kernel_supports(prog->obj, FEAT_PROG_BIND_MAP)) {
- struct bpf_map *rodata_map =
- &prog->obj->maps[prog->obj->rodata_map_idx];
+ if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) {
+ struct bpf_map *map;
+ int i;
+
+ for (i = 0; i < obj->nr_maps; i++) {
+ map = &prog->obj->maps[i];
+ if (map->libbpf_type != LIBBPF_MAP_RODATA)
+ continue;
- if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) {
- cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
- pr_warn("prog '%s': failed to bind .rodata map: %s\n",
- prog->name, cp);
- /* Don't fail hard if can't bind rodata. */
+ if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) {
+ cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
+ pr_warn("prog '%s': failed to bind .rodata map: %s\n",
+ prog->name, cp);
+ /* Don't fail hard if can't bind rodata. */
+ }
}
}
generated by cgit (git 2.34.1) at 2024-06-07 10:44:17 +0000