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Diffstat (limited to 'tools/lib/bpf/btf.c')
-rw-r--r--tools/lib/bpf/btf.c97
1 files changed, 96 insertions, 1 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index cf119c9b6f27..701e7e28ada3 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -24,6 +24,8 @@
((k) == BTF_KIND_CONST) || \
((k) == BTF_KIND_RESTRICT))
+#define IS_VAR(k) ((k) == BTF_KIND_VAR)
+
static struct btf_type btf_void;
struct btf {
@@ -212,6 +214,10 @@ static int btf_type_size(struct btf_type *t)
return base_size + vlen * sizeof(struct btf_member);
case BTF_KIND_FUNC_PROTO:
return base_size + vlen * sizeof(struct btf_param);
+ case BTF_KIND_VAR:
+ return base_size + sizeof(struct btf_var);
+ case BTF_KIND_DATASEC:
+ return base_size + vlen * sizeof(struct btf_var_secinfo);
default:
pr_debug("Unsupported BTF_KIND:%u\n", BTF_INFO_KIND(t->info));
return -EINVAL;
@@ -283,6 +289,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
case BTF_KIND_ENUM:
+ case BTF_KIND_DATASEC:
size = t->size;
goto done;
case BTF_KIND_PTR:
@@ -292,6 +299,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
+ case BTF_KIND_VAR:
type_id = t->type;
break;
case BTF_KIND_ARRAY:
@@ -326,7 +334,8 @@ int btf__resolve_type(const struct btf *btf, __u32 type_id)
t = btf__type_by_id(btf, type_id);
while (depth < MAX_RESOLVE_DEPTH &&
!btf_type_is_void_or_null(t) &&
- IS_MODIFIER(BTF_INFO_KIND(t->info))) {
+ (IS_MODIFIER(BTF_INFO_KIND(t->info)) ||
+ IS_VAR(BTF_INFO_KIND(t->info)))) {
type_id = t->type;
t = btf__type_by_id(btf, type_id);
depth++;
@@ -408,6 +417,92 @@ done:
return btf;
}
+static int compare_vsi_off(const void *_a, const void *_b)
+{
+ const struct btf_var_secinfo *a = _a;
+ const struct btf_var_secinfo *b = _b;
+
+ return a->offset - b->offset;
+}
+
+static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
+ struct btf_type *t)
+{
+ __u32 size = 0, off = 0, i, vars = BTF_INFO_VLEN(t->info);
+ const char *name = btf__name_by_offset(btf, t->name_off);
+ const struct btf_type *t_var;
+ struct btf_var_secinfo *vsi;
+ struct btf_var *var;
+ int ret;
+
+ if (!name) {
+ pr_debug("No name found in string section for DATASEC kind.\n");
+ return -ENOENT;
+ }
+
+ ret = bpf_object__section_size(obj, name, &size);
+ if (ret || !size || (t->size && t->size != size)) {
+ pr_debug("Invalid size for section %s: %u bytes\n", name, size);
+ return -ENOENT;
+ }
+
+ t->size = size;
+
+ for (i = 0, vsi = (struct btf_var_secinfo *)(t + 1);
+ i < vars; i++, vsi++) {
+ t_var = btf__type_by_id(btf, vsi->type);
+ var = (struct btf_var *)(t_var + 1);
+
+ if (BTF_INFO_KIND(t_var->info) != BTF_KIND_VAR) {
+ pr_debug("Non-VAR type seen in section %s\n", name);
+ return -EINVAL;
+ }
+
+ if (var->linkage == BTF_VAR_STATIC)
+ continue;
+
+ name = btf__name_by_offset(btf, t_var->name_off);
+ if (!name) {
+ pr_debug("No name found in string section for VAR kind\n");
+ return -ENOENT;
+ }
+
+ ret = bpf_object__variable_offset(obj, name, &off);
+ if (ret) {
+ pr_debug("No offset found in symbol table for VAR %s\n", name);
+ return -ENOENT;
+ }
+
+ vsi->offset = off;
+ }
+
+ qsort(t + 1, vars, sizeof(*vsi), compare_vsi_off);
+ return 0;
+}
+
+int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
+{
+ int err = 0;
+ __u32 i;
+
+ for (i = 1; i <= btf->nr_types; i++) {
+ struct btf_type *t = btf->types[i];
+
+ /* Loader needs to fix up some of the things compiler
+ * couldn't get its hands on while emitting BTF. This
+ * is section size and global variable offset. We use
+ * the info from the ELF itself for this purpose.
+ */
+ if (BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC) {
+ err = btf_fixup_datasec(obj, btf, t);
+ if (err)
+ break;
+ }
+ }
+
+ return err;
+}
+
int btf__load(struct btf *btf)
{
__u32 log_buf_size = BPF_LOG_BUF_SIZE;