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Diffstat (limited to 'tools/bpf/resolve_btfids/main.c')
-rw-r--r--tools/bpf/resolve_btfids/main.c92
1 files changed, 75 insertions, 17 deletions
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 27a23196d58e..d47191c6e55e 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;
@@ -131,6 +141,7 @@ struct object {
};
static int verbose;
+static int warnings;
static int eprintf(int level, int var, const char *fmt, ...)
{
@@ -161,7 +172,7 @@ 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 +330,7 @@ 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 +362,13 @@ 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.
@@ -391,6 +410,14 @@ static int elf_collect(struct object *obj)
obj->efile.idlist = data;
obj->efile.idlist_shndx = idx;
obj->efile.idlist_addr = sh.sh_addr;
+ } else if (!strcmp(name, BTF_BASE_ELF_SEC)) {
+ /* If a .BTF.base section is found, do not resolve
+ * BTF ids relative to vmlinux; resolve relative
+ * to the .BTF.base section instead. btf__parse_split()
+ * will take care of this once the base BTF it is
+ * passed is NULL.
+ */
+ obj->base_btf_path = NULL;
}
if (compressed_section_fix(elf, scn, &sh))
@@ -441,7 +468,7 @@ 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)) {
@@ -578,6 +605,7 @@ static int symbols_resolve(struct object *obj)
if (id->id) {
pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
str, id->id, type_id, id->id);
+ warnings++;
} else {
id->id = type_id;
(*nr)--;
@@ -599,8 +627,10 @@ static int id_patch(struct object *obj, struct btf_id *id)
int i;
/* For set, set8, id->id may be 0 */
- if (!id->id && !id->is_set && !id->is_set8)
+ if (!id->id && !id->is_set && !id->is_set8) {
pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
+ warnings++;
+ }
for (i = 0; i < id->addr_cnt; i++) {
unsigned long addr = id->addr[i];
@@ -649,19 +679,18 @@ 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 = NULL;
+ struct btf_id_set *set = NULL;
+ 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 +699,39 @@ 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((u32 *)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);
}
@@ -686,7 +740,7 @@ static int sets_patch(struct object *obj)
static int symbols_patch(struct object *obj)
{
- int err;
+ off_t err;
if (__symbols_patch(obj, &obj->structs) ||
__symbols_patch(obj, &obj->unions) ||
@@ -732,6 +786,7 @@ int main(int argc, const char **argv)
.funcs = RB_ROOT,
.sets = RB_ROOT,
};
+ bool fatal_warnings = false;
struct option btfid_options[] = {
OPT_INCR('v', "verbose", &verbose,
"be more verbose (show errors, etc)"),
@@ -739,6 +794,8 @@ int main(int argc, const char **argv)
"BTF data"),
OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
"path of file providing base BTF"),
+ OPT_BOOLEAN(0, "fatal_warnings", &fatal_warnings,
+ "turn warnings into errors"),
OPT_END()
};
int err = -1;
@@ -773,7 +830,8 @@ int main(int argc, const char **argv)
if (symbols_patch(&obj))
goto out;
- err = 0;
+ if (!(fatal_warnings && warnings))
+ err = 0;
out:
if (obj.efile.elf) {
elf_end(obj.efile.elf);
generated by cgit (git 2.34.1) at 2025-07-25 18:09:27 +0000