Support encoding of BTF kind layout data and crcs via
btf__new_empty_opts().
Current supported opts are base_btf, add_kind_layout and
add_crc.
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/lib/bpf/btf.c | 99 ++++++++++++++++++++++++++++++++++++++--
tools/lib/bpf/btf.h | 11 +++++
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 108 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 457997c2a43c..060a93809f64 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -16,6 +16,7 @@
#include <linux/err.h>
#include <linux/btf.h>
#include <gelf.h>
+#include <zlib.h>
#include "btf.h"
#include "bpf.h"
#include "libbpf.h"
@@ -882,8 +883,58 @@ void btf__free(struct btf *btf)
free(btf);
}
-static struct btf *btf_new_empty(struct btf *base_btf)
+static void btf_add_kind_layout(struct btf *btf, __u8 kind,
+ __u16 flags, __u8 info_sz, __u8 elem_sz)
{
+ struct btf_kind_layout *k = &btf->kind_layout[kind];
+
+ k->flags = flags;
+ k->info_sz = info_sz;
+ k->elem_sz = elem_sz;
+ btf->hdr->kind_layout_len += sizeof(*k);
+}
+
+static int btf_ensure_modifiable(struct btf *btf);
+
+static int btf_add_kind_layouts(struct btf *btf, struct btf_new_opts *opts)
+{
+ if (btf_ensure_modifiable(btf))
+ return libbpf_err(-ENOMEM);
+
+ btf->kind_layout = calloc(NR_BTF_KINDS, sizeof(struct btf_kind_layout));
+
+ if (!btf->kind_layout)
+ return -ENOMEM;
+
+ /* all supported kinds should describe their layout here. */
+ btf_add_kind_layout(btf, BTF_KIND_UNKN, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_INT, 0, sizeof(__u32), 0);
+ btf_add_kind_layout(btf, BTF_KIND_PTR, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_ARRAY, 0, sizeof(struct btf_array), 0);
+ btf_add_kind_layout(btf, BTF_KIND_STRUCT, 0, 0, sizeof(struct btf_member));
+ btf_add_kind_layout(btf, BTF_KIND_UNION, 0, 0, sizeof(struct btf_member));
+ btf_add_kind_layout(btf, BTF_KIND_ENUM, 0, 0, sizeof(struct btf_enum));
+ btf_add_kind_layout(btf, BTF_KIND_FWD, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_TYPEDEF, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_VOLATILE, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_CONST, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_RESTRICT, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_FUNC, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_FUNC_PROTO, 0, 0, sizeof(struct btf_param));
+ btf_add_kind_layout(btf, BTF_KIND_VAR, 0, sizeof(struct btf_var), 0);
+ btf_add_kind_layout(btf, BTF_KIND_DATASEC, 0, 0, sizeof(struct btf_var_secinfo));
+ btf_add_kind_layout(btf, BTF_KIND_FLOAT, 0, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_DECL_TAG, BTF_KIND_LAYOUT_OPTIONAL,
+ sizeof(struct btf_decl_tag), 0);
+ btf_add_kind_layout(btf, BTF_KIND_TYPE_TAG, BTF_KIND_LAYOUT_OPTIONAL, 0, 0);
+ btf_add_kind_layout(btf, BTF_KIND_ENUM64, 0, 0, sizeof(struct btf_enum64));
+
+ return 0;
+}
+
+static struct btf *btf_new_empty(struct btf_new_opts *opts)
+{
+ struct btf *base_btf = OPTS_GET(opts, base_btf, NULL);
struct btf *btf;
btf = calloc(1, sizeof(*btf));
@@ -920,17 +971,53 @@ static struct btf *btf_new_empty(struct btf *base_btf)
btf->strs_data = btf->raw_data + btf->hdr->hdr_len;
btf->hdr->str_len = base_btf ? 0 : 1; /* empty string at offset 0 */
+ if (opts->add_kind_layout) {
+ int err = btf_add_kind_layouts(btf, opts);
+
+ if (err) {
+ free(btf->raw_data);
+ free(btf);
+ return ERR_PTR(err);
+ }
+ }
+ if (opts->add_crc) {
+ if (btf->base_btf) {
+ struct btf_header *base_hdr = btf->base_btf->hdr;
+
+ if (base_hdr->hdr_len >= sizeof(struct btf_header) &&
+ base_hdr->flags & BTF_FLAG_CRC_SET) {
+ btf->hdr->base_crc = base_hdr->crc;
+ btf->hdr->flags |= BTF_FLAG_BASE_CRC_SET;
+ }
+ }
+ btf->hdr->flags |= BTF_FLAG_CRC_SET;
+ }
+
return btf;
}
struct btf *btf__new_empty(void)
{
- return libbpf_ptr(btf_new_empty(NULL));
+ LIBBPF_OPTS(btf_new_opts, opts);
+
+ return libbpf_ptr(btf_new_empty(&opts));
}
struct btf *btf__new_empty_split(struct btf *base_btf)
{
- return libbpf_ptr(btf_new_empty(base_btf));
+ LIBBPF_OPTS(btf_new_opts, opts);
+
+ opts.base_btf = base_btf;
+
+ return libbpf_ptr(btf_new_empty(&opts));
+}
+
+struct btf *btf__new_empty_opts(struct btf_new_opts *opts)
+{
+ if (!OPTS_VALID(opts, btf_new_opts))
+ return libbpf_err_ptr(-EINVAL);
+
+ return libbpf_ptr(btf_new_empty(opts));
}
static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf)
@@ -1377,6 +1464,12 @@ static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endi
btf_bswap_kind_layout_sec(p, hdr->kind_layout_len);
p += hdr->kind_layout_len;
}
+ if (hdr->flags & BTF_FLAG_CRC_SET) {
+ struct btf_header *h = data;
+
+ h->crc = crc32(0L, (const Bytef *)&data, sizeof(data));
+ }
+
*size = data_sz;
return data;
err_out:
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 8e6880d91c84..d25bd5c19eec 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -107,6 +107,17 @@ LIBBPF_API struct btf *btf__new_empty(void);
*/
LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
+struct btf_new_opts {
+ size_t sz;
+ struct btf *base_btf; /* optional base BTF */
+ bool add_kind_layout; /* add BTF kind layout information */
+ bool add_crc; /* add CRC information */
+ size_t:0;
+};
+#define btf_new_opts__last_field add_crc
+
+LIBBPF_API struct btf *btf__new_empty_opts(struct btf_new_opts *opts);
+
LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7521a2fb7626..edd8be4b21d0 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -395,4 +395,5 @@ LIBBPF_1.2.0 {
LIBBPF_1.3.0 {
global:
bpf_obj_pin_opts;
+ btf__new_empty_opts;
} LIBBPF_1.2.0;
--
2.39.3
