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Diffstat (limited to 'tools/bpf/bpftool/gen.c')
-rw-r--r--tools/bpf/bpftool/gen.c277
1 files changed, 264 insertions, 13 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index ee3ce2b800..540c0f2c4f 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -7,6 +7,7 @@
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
+#include <libgen.h>
#include <linux/err.h>
#include <stdbool.h>
#include <stdio.h>
@@ -54,11 +55,27 @@ static bool str_has_suffix(const char *str, const char *suffix)
return true;
}
+static const struct btf_type *
+resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
+{
+ const struct btf_type *t;
+
+ t = skip_mods_and_typedefs(btf, id, NULL);
+ if (!btf_is_ptr(t))
+ return NULL;
+
+ t = skip_mods_and_typedefs(btf, t->type, res_id);
+
+ return btf_is_func_proto(t) ? t : NULL;
+}
+
static void get_obj_name(char *name, const char *file)
{
- /* Using basename() GNU version which doesn't modify arg. */
- strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
- name[MAX_OBJ_NAME_LEN - 1] = '\0';
+ char file_copy[PATH_MAX];
+
+ /* Using basename() POSIX version to be more portable. */
+ strncpy(file_copy, file, PATH_MAX - 1)[PATH_MAX - 1] = '\0';
+ strncpy(name, basename(file_copy), MAX_OBJ_NAME_LEN - 1)[MAX_OBJ_NAME_LEN - 1] = '\0';
if (str_has_suffix(name, ".o"))
name[strlen(name) - 2] = '\0';
sanitize_identifier(name);
@@ -103,6 +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, ".addr_space.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];
@@ -231,8 +254,15 @@ static const struct btf_type *find_type_for_map(struct btf *btf, const char *map
return NULL;
}
-static bool is_internal_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
+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;
@@ -257,7 +287,7 @@ static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
bpf_object__for_each_map(map, obj) {
/* only generate definitions for memory-mapped internal maps */
- if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
+ if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
continue;
sec = find_type_for_map(btf, map_ident);
@@ -310,7 +340,7 @@ static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name
bpf_object__for_each_map(map, obj) {
/* only generate definitions for memory-mapped internal maps */
- if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
+ if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
continue;
sec = find_type_for_map(btf, map_ident);
@@ -487,7 +517,7 @@ static void codegen_asserts(struct bpf_object *obj, const char *obj_name)
", obj_name);
bpf_object__for_each_map(map, obj) {
- if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
+ if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
continue;
sec = find_type_for_map(btf, map_ident);
@@ -703,7 +733,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
const void *mmap_data = NULL;
size_t mmap_size = 0;
- if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ if (!is_mmapable_map(map, ident, sizeof(ident)))
continue;
codegen("\
@@ -765,7 +795,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
bpf_object__for_each_map(map, obj) {
const char *mmap_flags;
- if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ if (!is_mmapable_map(map, ident, sizeof(ident)))
continue;
if (bpf_map__map_flags(map) & BPF_F_RDONLY_PROG)
@@ -854,7 +884,7 @@ codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
",
i, bpf_map__name(map), i, ident);
/* memory-mapped internal maps */
- if (mmaped && is_internal_mmapable_map(map, ident, sizeof(ident))) {
+ if (mmaped && is_mmapable_map(map, ident, sizeof(ident))) {
printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
i, ident);
}
@@ -906,6 +936,207 @@ codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_li
}
}
+static int walk_st_ops_shadow_vars(struct btf *btf, const char *ident,
+ const struct btf_type *map_type, __u32 map_type_id)
+{
+ LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, .indent_level = 3);
+ const struct btf_type *member_type;
+ __u32 offset, next_offset = 0;
+ const struct btf_member *m;
+ struct btf_dump *d = NULL;
+ const char *member_name;
+ __u32 member_type_id;
+ int i, err = 0, n;
+ int size;
+
+ d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
+ if (!d)
+ return -errno;
+
+ n = btf_vlen(map_type);
+ for (i = 0, m = btf_members(map_type); i < n; i++, m++) {
+ member_type = skip_mods_and_typedefs(btf, m->type, &member_type_id);
+ member_name = btf__name_by_offset(btf, m->name_off);
+
+ offset = m->offset / 8;
+ if (next_offset < offset)
+ printf("\t\t\tchar __padding_%d[%d];\n", i, offset - next_offset);
+
+ switch (btf_kind(member_type)) {
+ case BTF_KIND_INT:
+ case BTF_KIND_FLOAT:
+ case BTF_KIND_ENUM:
+ case BTF_KIND_ENUM64:
+ /* scalar type */
+ printf("\t\t\t");
+ opts.field_name = member_name;
+ err = btf_dump__emit_type_decl(d, member_type_id, &opts);
+ if (err) {
+ p_err("Failed to emit type declaration for %s: %d", member_name, err);
+ goto out;
+ }
+ printf(";\n");
+
+ size = btf__resolve_size(btf, member_type_id);
+ if (size < 0) {
+ p_err("Failed to resolve size of %s: %d\n", member_name, size);
+ err = size;
+ goto out;
+ }
+
+ next_offset = offset + size;
+ break;
+
+ case BTF_KIND_PTR:
+ if (resolve_func_ptr(btf, m->type, NULL)) {
+ /* Function pointer */
+ printf("\t\t\tstruct bpf_program *%s;\n", member_name);
+
+ next_offset = offset + sizeof(void *);
+ break;
+ }
+ /* All pointer types are unsupported except for
+ * function pointers.
+ */
+ fallthrough;
+
+ default:
+ /* Unsupported types
+ *
+ * Types other than scalar types and function
+ * pointers are currently not supported in order to
+ * prevent conflicts in the generated code caused
+ * by multiple definitions. For instance, if the
+ * struct type FOO is used in a struct_ops map,
+ * bpftool has to generate definitions for FOO,
+ * which may result in conflicts if FOO is defined
+ * in different skeleton files.
+ */
+ size = btf__resolve_size(btf, member_type_id);
+ if (size < 0) {
+ p_err("Failed to resolve size of %s: %d\n", member_name, size);
+ err = size;
+ goto out;
+ }
+ printf("\t\t\tchar __unsupported_%d[%d];\n", i, size);
+
+ next_offset = offset + size;
+ break;
+ }
+ }
+
+ /* Cannot fail since it must be a struct type */
+ size = btf__resolve_size(btf, map_type_id);
+ if (next_offset < (__u32)size)
+ printf("\t\t\tchar __padding_end[%d];\n", size - next_offset);
+
+out:
+ btf_dump__free(d);
+
+ return err;
+}
+
+/* Generate the pointer of the shadow type for a struct_ops map.
+ *
+ * This function adds a pointer of the shadow type for a struct_ops map.
+ * The members of a struct_ops map can be exported through a pointer to a
+ * shadow type. The user can access these members through the pointer.
+ *
+ * A shadow type includes not all members, only members of some types.
+ * They are scalar types and function pointers. The function pointers are
+ * translated to the pointer of the struct bpf_program. The scalar types
+ * are translated to the original type without any modifiers.
+ *
+ * Unsupported types will be translated to a char array to occupy the same
+ * space as the original field, being renamed as __unsupported_*. The user
+ * should treat these fields as opaque data.
+ */
+static int gen_st_ops_shadow_type(const char *obj_name, struct btf *btf, const char *ident,
+ const struct bpf_map *map)
+{
+ const struct btf_type *map_type;
+ const char *type_name;
+ __u32 map_type_id;
+ int err;
+
+ map_type_id = bpf_map__btf_value_type_id(map);
+ if (map_type_id == 0)
+ return -EINVAL;
+ map_type = btf__type_by_id(btf, map_type_id);
+ if (!map_type)
+ return -EINVAL;
+
+ type_name = btf__name_by_offset(btf, map_type->name_off);
+
+ printf("\t\tstruct %s__%s__%s {\n", obj_name, ident, type_name);
+
+ err = walk_st_ops_shadow_vars(btf, ident, map_type, map_type_id);
+ if (err)
+ return err;
+
+ printf("\t\t} *%s;\n", ident);
+
+ return 0;
+}
+
+static int gen_st_ops_shadow(const char *obj_name, struct btf *btf, struct bpf_object *obj)
+{
+ int err, st_ops_cnt = 0;
+ struct bpf_map *map;
+ char ident[256];
+
+ if (!btf)
+ return 0;
+
+ /* Generate the pointers to shadow types of
+ * struct_ops maps.
+ */
+ bpf_object__for_each_map(map, obj) {
+ if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS)
+ continue;
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+
+ if (st_ops_cnt == 0) /* first struct_ops map */
+ printf("\tstruct {\n");
+ st_ops_cnt++;
+
+ err = gen_st_ops_shadow_type(obj_name, btf, ident, map);
+ if (err)
+ return err;
+ }
+
+ if (st_ops_cnt)
+ printf("\t} struct_ops;\n");
+
+ return 0;
+}
+
+/* Generate the code to initialize the pointers of shadow types. */
+static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj)
+{
+ struct bpf_map *map;
+ char ident[256];
+
+ if (!btf)
+ return;
+
+ /* Initialize the pointers to_ops shadow types of
+ * struct_ops maps.
+ */
+ bpf_object__for_each_map(map, obj) {
+ if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS)
+ continue;
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+ codegen("\
+ \n\
+ obj->struct_ops.%1$s = bpf_map__initial_value(obj->maps.%1$s, NULL);\n\
+ \n\
+ ", ident);
+ }
+}
+
static int do_skeleton(int argc, char **argv)
{
char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
@@ -1049,6 +1280,11 @@ static int do_skeleton(int argc, char **argv)
printf("\t} maps;\n");
}
+ btf = bpf_object__btf(obj);
+ err = gen_st_ops_shadow(obj_name, btf, obj);
+ if (err)
+ goto out;
+
if (prog_cnt) {
printf("\tstruct {\n");
bpf_object__for_each_program(prog, obj) {
@@ -1072,7 +1308,6 @@ static int do_skeleton(int argc, char **argv)
printf("\t} links;\n");
}
- btf = bpf_object__btf(obj);
if (btf) {
err = codegen_datasecs(obj, obj_name);
if (err)
@@ -1130,6 +1365,12 @@ static int do_skeleton(int argc, char **argv)
if (err) \n\
goto err_out; \n\
\n\
+ ", obj_name);
+
+ gen_st_ops_shadow_init(btf, obj);
+
+ codegen("\
+ \n\
return obj; \n\
err_out: \n\
%1$s__destroy(obj); \n\
@@ -1389,7 +1630,7 @@ static int do_subskeleton(int argc, char **argv)
/* Also count all maps that have a name */
map_cnt++;
- if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ if (!is_mmapable_map(map, ident, sizeof(ident)))
continue;
map_type_id = bpf_map__btf_value_type_id(map);
@@ -1439,6 +1680,10 @@ static int do_subskeleton(int argc, char **argv)
printf("\t} maps;\n");
}
+ err = gen_st_ops_shadow(obj_name, btf, obj);
+ if (err)
+ goto out;
+
if (prog_cnt) {
printf("\tstruct {\n");
bpf_object__for_each_program(prog, obj) {
@@ -1507,7 +1752,7 @@ static int do_subskeleton(int argc, char **argv)
/* walk through each symbol and emit the runtime representation */
bpf_object__for_each_map(map, obj) {
- if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ if (!is_mmapable_map(map, ident, sizeof(ident)))
continue;
map_type_id = bpf_map__btf_value_type_id(map);
@@ -1550,6 +1795,12 @@ static int do_subskeleton(int argc, char **argv)
if (err) \n\
goto err; \n\
\n\
+ ");
+
+ gen_st_ops_shadow_init(btf, obj);
+
+ codegen("\
+ \n\
return obj; \n\
err: \n\
%1$s__destroy(obj); \n\