diff options
Diffstat (limited to 'tools/bpf/resolve_btfids')
| -rw-r--r-- | tools/bpf/resolve_btfids/main.c | 70 |
1 files changed, 56 insertions, 14 deletions
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c index 770581740..ef0764d68 100644 --- a/tools/bpf/resolve_btfids/main.c +++ b/tools/bpf/resolve_btfids/main.c @@ -70,6 +70,7 @@ #include <sys/stat.h> #include <fcntl.h> #include <errno.h> +#include <linux/btf_ids.h> #include <linux/rbtree.h> #include <linux/zalloc.h> #include <linux/err.h> @@ -78,7 +79,7 @@ #include <subcmd/parse-options.h> #define BTF_IDS_SECTION ".BTF_ids" -#define BTF_ID "__BTF_ID__" +#define BTF_ID_PREFIX "__BTF_ID__" #define BTF_STRUCT "struct" #define BTF_UNION "union" @@ -89,6 +90,14 @@ #define ADDR_CNT 100 +#if __BYTE_ORDER == __LITTLE_ENDIAN +# define ELFDATANATIVE ELFDATA2LSB +#elif __BYTE_ORDER == __BIG_ENDIAN +# define ELFDATANATIVE ELFDATA2MSB +#else +# error "Unknown machine endianness!" +#endif + struct btf_id { struct rb_node rb_node; char *name; @@ -116,6 +125,7 @@ struct object { int idlist_shndx; size_t strtabidx; unsigned long idlist_addr; + int encoding; } efile; struct rb_root sets; @@ -161,7 +171,7 @@ static int eprintf(int level, int var, const char *fmt, ...) static bool is_btf_id(const char *name) { - return name && !strncmp(name, BTF_ID, sizeof(BTF_ID) - 1); + return name && !strncmp(name, BTF_ID_PREFIX, sizeof(BTF_ID_PREFIX) - 1); } static struct btf_id *btf_id__find(struct rb_root *root, const char *name) @@ -319,6 +329,7 @@ static int elf_collect(struct object *obj) { Elf_Scn *scn = NULL; size_t shdrstrndx; + GElf_Ehdr ehdr; int idx = 0; Elf *elf; int fd; @@ -350,6 +361,13 @@ static int elf_collect(struct object *obj) return -1; } + if (gelf_getehdr(obj->efile.elf, &ehdr) == NULL) { + pr_err("FAILED cannot get ELF header: %s\n", + elf_errmsg(-1)); + return -1; + } + obj->efile.encoding = ehdr.e_ident[EI_DATA]; + /* * Scan all the elf sections and look for save data * from .BTF_ids section and symbols. @@ -441,7 +459,7 @@ static int symbols_collect(struct object *obj) * __BTF_ID__TYPE__vfs_truncate__0 * prefix = ^ */ - prefix = name + sizeof(BTF_ID) - 1; + prefix = name + sizeof(BTF_ID_PREFIX) - 1; /* struct */ if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) { @@ -649,19 +667,18 @@ static int cmp_id(const void *pa, const void *pb) static int sets_patch(struct object *obj) { Elf_Data *data = obj->efile.idlist; - int *ptr = data->d_buf; struct rb_node *next; next = rb_first(&obj->sets); while (next) { - unsigned long addr, idx; + struct btf_id_set8 *set8; + struct btf_id_set *set; + unsigned long addr, off; struct btf_id *id; - int *base; - int cnt; id = rb_entry(next, struct btf_id, rb_node); addr = id->addr[0]; - idx = addr - obj->efile.idlist_addr; + off = addr - obj->efile.idlist_addr; /* sets are unique */ if (id->addr_cnt != 1) { @@ -670,14 +687,39 @@ static int sets_patch(struct object *obj) return -1; } - idx = idx / sizeof(int); - base = &ptr[idx] + (id->is_set8 ? 2 : 1); - cnt = ptr[idx]; + if (id->is_set) { + set = data->d_buf + off; + qsort(set->ids, set->cnt, sizeof(set->ids[0]), cmp_id); + } else { + set8 = data->d_buf + off; + /* + * Make sure id is at the beginning of the pairs + * struct, otherwise the below qsort would not work. + */ + BUILD_BUG_ON(set8->pairs != &set8->pairs[0].id); + qsort(set8->pairs, set8->cnt, sizeof(set8->pairs[0]), cmp_id); - pr_debug("sorting addr %5lu: cnt %6d [%s]\n", - (idx + 1) * sizeof(int), cnt, id->name); + /* + * When ELF endianness does not match endianness of the + * host, libelf will do the translation when updating + * the ELF. This, however, corrupts SET8 flags which are + * already in the target endianness. So, let's bswap + * them to the host endianness and libelf will then + * correctly translate everything. + */ + if (obj->efile.encoding != ELFDATANATIVE) { + int i; + + set8->flags = bswap_32(set8->flags); + for (i = 0; i < set8->cnt; i++) { + set8->pairs[i].flags = + bswap_32(set8->pairs[i].flags); + } + } + } - qsort(base, cnt, id->is_set8 ? sizeof(uint64_t) : sizeof(int), cmp_id); + pr_debug("sorting addr %5lu: cnt %6d [%s]\n", + off, id->is_set ? set->cnt : set8->cnt, id->name); next = rb_next(next); } |