* [PATCH bpf-next v6 1/8] libbpf: Improve log message formatting
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 2/8] libbpf: Fix header comment typos for BTF.ext Tony Ambardar
` (7 subsequent siblings)
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Fix missing newlines and extraneous terminal spaces in messages.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/btf.c | 6 +++---
tools/lib/bpf/btf_dump.c | 2 +-
tools/lib/bpf/btf_relocate.c | 2 +-
tools/lib/bpf/libbpf.c | 4 ++--
tools/lib/bpf/relo_core.c | 2 +-
5 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 3c131039c523..e1d4cbd83729 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -2941,7 +2941,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
/* If no records, return failure now so .BTF.ext won't be used. */
if (!info_left) {
- pr_debug("%s section in .BTF.ext has no records", ext_sec->desc);
+ pr_debug("%s section in .BTF.ext has no records\n", ext_sec->desc);
return -EINVAL;
}
@@ -3029,7 +3029,7 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
if (data_size < offsetofend(struct btf_ext_header, hdr_len) ||
data_size < hdr->hdr_len) {
- pr_debug("BTF.ext header not found");
+ pr_debug("BTF.ext header not found\n");
return -EINVAL;
}
@@ -3291,7 +3291,7 @@ int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts)
d = btf_dedup_new(btf, opts);
if (IS_ERR(d)) {
- pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d));
+ pr_debug("btf_dedup_new failed: %ld\n", PTR_ERR(d));
return libbpf_err(-EINVAL);
}
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 0a7327541c17..8440c2c5ad3e 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -1304,7 +1304,7 @@ static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
* chain, restore stack, emit warning, and try to
* proceed nevertheless
*/
- pr_warn("not enough memory for decl stack:%d", err);
+ pr_warn("not enough memory for decl stack: %d\n", err);
d->decl_stack_cnt = stack_start;
return;
}
diff --git a/tools/lib/bpf/btf_relocate.c b/tools/lib/bpf/btf_relocate.c
index 4f7399d85eab..b72f83e15156 100644
--- a/tools/lib/bpf/btf_relocate.c
+++ b/tools/lib/bpf/btf_relocate.c
@@ -428,7 +428,7 @@ static int btf_relocate_rewrite_strs(struct btf_relocate *r, __u32 i)
} else {
off = r->str_map[*str_off];
if (!off) {
- pr_warn("string '%s' [offset %u] is not mapped to base BTF",
+ pr_warn("string '%s' [offset %u] is not mapped to base BTF\n",
btf__str_by_offset(r->btf, off), *str_off);
return -ENOENT;
}
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 219facd0e66e..60b69c6aaf53 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -12760,7 +12760,7 @@ struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
}
if (prog->type != BPF_PROG_TYPE_EXT) {
- pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace",
+ pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace\n",
prog->name);
return libbpf_err_ptr(-EINVAL);
}
@@ -13834,7 +13834,7 @@ int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s)
map_type = btf__type_by_id(btf, map_type_id);
if (!btf_is_datasec(map_type)) {
- pr_warn("type for map '%1$s' is not a datasec: %2$s",
+ pr_warn("type for map '%1$s' is not a datasec: %2$s\n",
bpf_map__name(map),
__btf_kind_str(btf_kind(map_type)));
return libbpf_err(-EINVAL);
diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index 63a4d5ad12d1..7632e9d41827 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -1339,7 +1339,7 @@ int bpf_core_calc_relo_insn(const char *prog_name,
cands->cands[i].id, cand_spec);
if (err < 0) {
bpf_core_format_spec(spec_buf, sizeof(spec_buf), cand_spec);
- pr_warn("prog '%s': relo #%d: error matching candidate #%d %s: %d\n ",
+ pr_warn("prog '%s': relo #%d: error matching candidate #%d %s: %d\n",
prog_name, relo_idx, i, spec_buf, err);
return err;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 2/8] libbpf: Fix header comment typos for BTF.ext
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 1/8] libbpf: Improve log message formatting Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 3/8] libbpf: Fix output .symtab byte-order during linking Tony Ambardar
` (6 subsequent siblings)
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Mention struct btf_ext_info_sec rather than non-existent btf_sec_func_info
in BTF.ext struct documentation.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/libbpf_internal.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 408df59e0771..8cda511a1982 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -448,11 +448,11 @@ struct btf_ext_info {
*
* The func_info subsection layout:
* record size for struct bpf_func_info in the func_info subsection
- * struct btf_sec_func_info for section #1
+ * struct btf_ext_info_sec for section #1
* a list of bpf_func_info records for section #1
* where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
* but may not be identical
- * struct btf_sec_func_info for section #2
+ * struct btf_ext_info_sec for section #2
* a list of bpf_func_info records for section #2
* ......
*
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 3/8] libbpf: Fix output .symtab byte-order during linking
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 1/8] libbpf: Improve log message formatting Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 2/8] libbpf: Fix header comment typos for BTF.ext Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 4/8] libbpf: Support BTF.ext loading and output in either endianness Tony Ambardar
` (5 subsequent siblings)
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Object linking output data uses the default ELF_T_BYTE type for '.symtab'
section data, which disables any libelf-based translation. Explicitly set
the ELF_T_SYM type for output to restore libelf's byte-order conversion,
noting that input '.symtab' data is already correctly translated.
Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs")
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/linker.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index e0005c6ade88..6985ab0f1ca9 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -396,6 +396,8 @@ static int init_output_elf(struct bpf_linker *linker, const char *file)
pr_warn_elf("failed to create SYMTAB data");
return -EINVAL;
}
+ /* Ensure libelf translates byte-order of symbol records */
+ sec->data->d_type = ELF_T_SYM;
str_off = strset__add_str(linker->strtab_strs, sec->sec_name);
if (str_off < 0)
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 4/8] libbpf: Support BTF.ext loading and output in either endianness
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (2 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 3/8] libbpf: Fix output .symtab byte-order during linking Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-27 21:47 ` Andrii Nakryiko
2024-09-16 8:37 ` [PATCH bpf-next v6 5/8] libbpf: Support opening bpf objects of " Tony Ambardar
` (4 subsequent siblings)
8 siblings, 1 reply; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Support for handling BTF data of either endianness was added in [1], but
did not include BTF.ext data for lack of use cases. Later, support for
static linking [2] provided a use case, but this feature and later ones
were restricted to native-endian usage.
Add support for BTF.ext handling in either endianness. Convert BTF.ext data
to native endianness when read into memory for further processing, and
support raw data access that restores the original byte-order for output.
Add internal header functions for byte-swapping func, line, and core info
records.
Add new API functions btf_ext__endianness() and btf_ext__set_endianness()
for query and setting byte-order, as already exist for BTF data.
[1] 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness")
[2] 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support")
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/btf.c | 280 +++++++++++++++++++++++++-------
tools/lib/bpf/btf.h | 3 +
tools/lib/bpf/libbpf.map | 2 +
tools/lib/bpf/libbpf_internal.h | 30 ++++
4 files changed, 258 insertions(+), 57 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index e1d4cbd83729..c04f37b87f25 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -2885,22 +2885,29 @@ int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
return btf_commit_type(btf, sz);
}
-struct btf_ext_sec_setup_param {
+struct btf_ext_sec_info_param {
__u32 off;
__u32 len;
__u32 min_rec_size;
+ __u32 rec_size;
struct btf_ext_info *ext_info;
const char *desc;
};
-static int btf_ext_setup_info(struct btf_ext *btf_ext,
- struct btf_ext_sec_setup_param *ext_sec)
+/*
+ * Parse a single info subsection of the BTF.ext info data:
+ * - validate subsection structure and elements
+ * - save info subsection start and sizing details in struct btf_ext
+ * - endian-independent operation, for calling before byte-swapping
+ */
+static int btf_ext_parse_sec_info(struct btf_ext *btf_ext,
+ struct btf_ext_sec_info_param *ext_sec,
+ bool is_native)
{
const struct btf_ext_info_sec *sinfo;
struct btf_ext_info *ext_info;
__u32 info_left, record_size;
size_t sec_cnt = 0;
- /* The start of the info sec (including the __u32 record_size). */
void *info;
if (ext_sec->len == 0)
@@ -2912,6 +2919,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
return -EINVAL;
}
+ /* The start of the info sec (including the __u32 record_size). */
info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
info_left = ext_sec->len;
@@ -2927,9 +2935,13 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
return -EINVAL;
}
- /* The record size needs to meet the minimum standard */
- record_size = *(__u32 *)info;
+ /* The record size needs to meet either the minimum standard or, when
+ * handling non-native endianness data, the exact standard so as
+ * to allow safe byte-swapping.
+ */
+ record_size = is_native ? *(__u32 *)info : bswap_32(*(__u32 *)info);
if (record_size < ext_sec->min_rec_size ||
+ (!is_native && record_size != ext_sec->rec_size) ||
record_size & 0x03) {
pr_debug("%s section in .BTF.ext has invalid record size %u\n",
ext_sec->desc, record_size);
@@ -2956,7 +2968,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
return -EINVAL;
}
- num_records = sinfo->num_info;
+ num_records = is_native ? sinfo->num_info : bswap_32(sinfo->num_info);
if (num_records == 0) {
pr_debug("%s section has incorrect num_records in .BTF.ext\n",
ext_sec->desc);
@@ -2984,64 +2996,160 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
return 0;
}
-static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
+/* Parse all info secs in the BTF.ext info data */
+static int btf_ext_parse_info(struct btf_ext *btf_ext, bool is_native)
{
- struct btf_ext_sec_setup_param param = {
+ struct btf_ext_sec_info_param func_info = {
.off = btf_ext->hdr->func_info_off,
.len = btf_ext->hdr->func_info_len,
.min_rec_size = sizeof(struct bpf_func_info_min),
+ .rec_size = sizeof(struct bpf_func_info),
.ext_info = &btf_ext->func_info,
.desc = "func_info"
};
-
- return btf_ext_setup_info(btf_ext, ¶m);
-}
-
-static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
-{
- struct btf_ext_sec_setup_param param = {
+ struct btf_ext_sec_info_param line_info = {
.off = btf_ext->hdr->line_info_off,
.len = btf_ext->hdr->line_info_len,
.min_rec_size = sizeof(struct bpf_line_info_min),
+ .rec_size = sizeof(struct bpf_line_info),
.ext_info = &btf_ext->line_info,
.desc = "line_info",
};
-
- return btf_ext_setup_info(btf_ext, ¶m);
-}
-
-static int btf_ext_setup_core_relos(struct btf_ext *btf_ext)
-{
- struct btf_ext_sec_setup_param param = {
+ struct btf_ext_sec_info_param core_relo = {
.off = btf_ext->hdr->core_relo_off,
.len = btf_ext->hdr->core_relo_len,
.min_rec_size = sizeof(struct bpf_core_relo),
+ .rec_size = sizeof(struct bpf_core_relo),
.ext_info = &btf_ext->core_relo_info,
.desc = "core_relo",
};
+ int err;
+
+ err = btf_ext_parse_sec_info(btf_ext, &func_info, is_native);
+ if (err)
+ return err;
+
+ err = btf_ext_parse_sec_info(btf_ext, &line_info, is_native);
+ if (err)
+ return err;
+
+ if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+ return 0; /* skip core relos parsing */
- return btf_ext_setup_info(btf_ext, ¶m);
+ err = btf_ext_parse_sec_info(btf_ext, &core_relo, is_native);
+ if (err)
+ return err;
+
+ return 0;
}
-static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
+/* Swap byte-order of BTF.ext header with any endianness */
+static void btf_ext_bswap_hdr(struct btf_ext_header *h)
{
- const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
+ bool is_native = h->magic == BTF_MAGIC;
+ __u32 hdr_len;
- if (data_size < offsetofend(struct btf_ext_header, hdr_len) ||
- data_size < hdr->hdr_len) {
- pr_debug("BTF.ext header not found\n");
+ hdr_len = is_native ? h->hdr_len : bswap_32(h->hdr_len);
+
+ h->magic = bswap_16(h->magic);
+ h->hdr_len = bswap_32(h->hdr_len);
+ h->func_info_off = bswap_32(h->func_info_off);
+ h->func_info_len = bswap_32(h->func_info_len);
+ h->line_info_off = bswap_32(h->line_info_off);
+ h->line_info_len = bswap_32(h->line_info_len);
+
+ if (hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+ return;
+
+ h->core_relo_off = bswap_32(h->core_relo_off);
+ h->core_relo_len = bswap_32(h->core_relo_len);
+}
+
+/* Swap byte-order of generic info subsection */
+static void btf_ext_bswap_info_sec(void *info, __u32 len, bool is_native,
+ info_rec_bswap_fn bswap_fn)
+{
+ struct btf_ext_info_sec *sec;
+ __u32 info_left, rec_size, *rs;
+
+ if (len == 0)
+ return;
+
+ rs = info; /* info record size */
+ rec_size = is_native ? *rs : bswap_32(*rs);
+ *rs = bswap_32(*rs);
+
+ sec = info + sizeof(__u32); /* info sec #1 */
+ info_left = len - sizeof(__u32);
+ while (info_left) {
+ unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
+ __u32 i, num_recs;
+ void *p;
+
+ num_recs = is_native ? sec->num_info : bswap_32(sec->num_info);
+ sec->sec_name_off = bswap_32(sec->sec_name_off);
+ sec->num_info = bswap_32(sec->num_info);
+ p = sec->data; /* info rec #1 */
+ for (i = 0; i < num_recs; i++, p += rec_size)
+ bswap_fn(p);
+ sec = p;
+ info_left -= sec_hdrlen + (__u64)rec_size * num_recs;
+ }
+}
+
+/*
+ * Swap byte-order of all info data in a BTF.ext section
+ * - requires BTF.ext hdr in native endianness
+ */
+static void btf_ext_bswap_info(struct btf_ext *btf_ext, void *data)
+{
+ const bool is_native = btf_ext->swapped_endian;
+ const struct btf_ext_header *h = data;
+ void *info;
+
+ /* Swap func_info subsection byte-order */
+ info = data + h->hdr_len + h->func_info_off;
+ btf_ext_bswap_info_sec(info, h->func_info_len, is_native,
+ (info_rec_bswap_fn)bpf_func_info_bswap);
+
+ /* Swap line_info subsection byte-order */
+ info = data + h->hdr_len + h->line_info_off;
+ btf_ext_bswap_info_sec(info, h->line_info_len, is_native,
+ (info_rec_bswap_fn)bpf_line_info_bswap);
+
+ /* Swap core_relo subsection byte-order (if present) */
+ if (h->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+ return;
+
+ info = data + h->hdr_len + h->core_relo_off;
+ btf_ext_bswap_info_sec(info, h->core_relo_len, is_native,
+ (info_rec_bswap_fn)bpf_core_relo_bswap);
+}
+
+/* Parse hdr data and info sections: check and convert to native endianness */
+static int btf_ext_parse(struct btf_ext *btf_ext)
+{
+ __u32 hdr_len, data_size = btf_ext->data_size;
+ struct btf_ext_header *hdr = btf_ext->hdr;
+ bool swapped_endian = false;
+ int err;
+
+ if (data_size < offsetofend(struct btf_ext_header, hdr_len)) {
+ pr_debug("BTF.ext header too short\n");
return -EINVAL;
}
+ hdr_len = hdr->hdr_len;
if (hdr->magic == bswap_16(BTF_MAGIC)) {
- pr_warn("BTF.ext in non-native endianness is not supported\n");
- return -ENOTSUP;
+ swapped_endian = true;
+ hdr_len = bswap_32(hdr_len);
} else if (hdr->magic != BTF_MAGIC) {
pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
return -EINVAL;
}
- if (hdr->version != BTF_VERSION) {
+ /* Ensure known version of structs, current BTF_VERSION == 1 */
+ if (hdr->version != 1) {
pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
return -ENOTSUP;
}
@@ -3051,11 +3159,39 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
return -ENOTSUP;
}
- if (data_size == hdr->hdr_len) {
+ if (data_size < hdr_len) {
+ pr_debug("BTF.ext header not found\n");
+ return -EINVAL;
+ } else if (data_size == hdr_len) {
pr_debug("BTF.ext has no data\n");
return -EINVAL;
}
+ /* Verify mandatory hdr info details present */
+ if (hdr_len < offsetofend(struct btf_ext_header, line_info_len)) {
+ pr_warn("BTF.ext header missing func_info, line_info\n");
+ return -EINVAL;
+ }
+
+ /* Keep hdr native byte-order in memory for introspection */
+ if (swapped_endian)
+ btf_ext_bswap_hdr(btf_ext->hdr);
+
+ /* Validate info subsections and cache key metadata */
+ err = btf_ext_parse_info(btf_ext, !swapped_endian);
+ if (err)
+ return err;
+
+ /* Keep infos native byte-order in memory for introspection */
+ if (swapped_endian)
+ btf_ext_bswap_info(btf_ext, btf_ext->data);
+
+ /*
+ * Set btf_ext->swapped_endian only after all header and info data has
+ * been swapped, helping bswap functions determine if their data are
+ * in native byte-order when called.
+ */
+ btf_ext->swapped_endian = swapped_endian;
return 0;
}
@@ -3067,6 +3203,7 @@ void btf_ext__free(struct btf_ext *btf_ext)
free(btf_ext->line_info.sec_idxs);
free(btf_ext->core_relo_info.sec_idxs);
free(btf_ext->data);
+ free(btf_ext->data_swapped);
free(btf_ext);
}
@@ -3087,29 +3224,7 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size)
}
memcpy(btf_ext->data, data, size);
- err = btf_ext_parse_hdr(btf_ext->data, size);
- if (err)
- goto done;
-
- if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) {
- err = -EINVAL;
- goto done;
- }
-
- err = btf_ext_setup_func_info(btf_ext);
- if (err)
- goto done;
-
- err = btf_ext_setup_line_info(btf_ext);
- if (err)
- goto done;
-
- if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
- goto done; /* skip core relos parsing */
-
- err = btf_ext_setup_core_relos(btf_ext);
- if (err)
- goto done;
+ err = btf_ext_parse(btf_ext);
done:
if (err) {
@@ -3120,15 +3235,66 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size)
return btf_ext;
}
+static void *btf_ext_raw_data(const struct btf_ext *btf_ext_ro, bool swap_endian)
+{
+ struct btf_ext *btf_ext = (struct btf_ext *)btf_ext_ro;
+ const __u32 data_sz = btf_ext->data_size;
+ void *data;
+
+ /* Return native data (always present) or swapped data if present */
+ if (!swap_endian)
+ return btf_ext->data;
+ else if (btf_ext->data_swapped)
+ return btf_ext->data_swapped;
+
+ /* Recreate missing swapped data, then cache and return */
+ data = calloc(1, data_sz);
+ if (!data)
+ return NULL;
+ memcpy(data, btf_ext->data, data_sz);
+
+ btf_ext_bswap_info(btf_ext, data);
+ btf_ext_bswap_hdr(data);
+ btf_ext->data_swapped = data;
+ return data;
+}
+
const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size)
{
+ void *data;
+
+ data = btf_ext_raw_data(btf_ext, btf_ext->swapped_endian);
+ if (!data)
+ return errno = ENOMEM, NULL;
+
*size = btf_ext->data_size;
- return btf_ext->data;
+ return data;
}
__attribute__((alias("btf_ext__raw_data")))
const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size);
+enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext)
+{
+ if (is_host_big_endian())
+ return btf_ext->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN;
+ else
+ return btf_ext->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+}
+
+int btf_ext__set_endianness(struct btf_ext *btf_ext, enum btf_endianness endian)
+{
+ if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN)
+ return libbpf_err(-EINVAL);
+
+ btf_ext->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN);
+
+ if (!btf_ext->swapped_endian) {
+ free(btf_ext->data_swapped);
+ btf_ext->data_swapped = NULL;
+ }
+ return 0;
+}
struct btf_dedup;
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 4e349ad79ee6..47ee8f6ac489 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -167,6 +167,9 @@ LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
+LIBBPF_API enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext);
+LIBBPF_API int btf_ext__set_endianness(struct btf_ext *btf_ext,
+ enum btf_endianness endian);
LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 0096e483f7eb..f40ccc2946e7 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -421,6 +421,8 @@ LIBBPF_1.5.0 {
global:
btf__distill_base;
btf__relocate;
+ btf_ext__endianness;
+ btf_ext__set_endianness;
bpf_map__autoattach;
bpf_map__set_autoattach;
bpf_object__token_fd;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 8cda511a1982..1307753b49b3 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -484,6 +484,8 @@ struct btf_ext {
struct btf_ext_header *hdr;
void *data;
};
+ void *data_swapped;
+ bool swapped_endian;
struct btf_ext_info func_info;
struct btf_ext_info line_info;
struct btf_ext_info core_relo_info;
@@ -511,6 +513,34 @@ struct bpf_line_info_min {
__u32 line_col;
};
+/* Functions to byte-swap info records */
+
+typedef void (*info_rec_bswap_fn)(void *);
+
+static inline void bpf_func_info_bswap(struct bpf_func_info *i)
+{
+ i->insn_off = bswap_32(i->insn_off);
+ i->type_id = bswap_32(i->type_id);
+}
+
+static inline void bpf_line_info_bswap(struct bpf_line_info *i)
+{
+ i->insn_off = bswap_32(i->insn_off);
+ i->file_name_off = bswap_32(i->file_name_off);
+ i->line_off = bswap_32(i->line_off);
+ i->line_col = bswap_32(i->line_col);
+}
+
+static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
+{
+ _Static_assert(sizeof(i->kind) == sizeof(__u32),
+ "enum bpf_core_relo_kind is not 32-bit\n");
+ i->insn_off = bswap_32(i->insn_off);
+ i->type_id = bswap_32(i->type_id);
+ i->access_str_off = bswap_32(i->access_str_off);
+ i->kind = bswap_32(i->kind);
+}
+
enum btf_field_iter_kind {
BTF_FIELD_ITER_IDS,
BTF_FIELD_ITER_STRS,
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH bpf-next v6 4/8] libbpf: Support BTF.ext loading and output in either endianness
2024-09-16 8:37 ` [PATCH bpf-next v6 4/8] libbpf: Support BTF.ext loading and output in either endianness Tony Ambardar
@ 2024-09-27 21:47 ` Andrii Nakryiko
0 siblings, 0 replies; 11+ messages in thread
From: Andrii Nakryiko @ 2024-09-27 21:47 UTC (permalink / raw)
To: Tony Ambardar
Cc: bpf, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
On Mon, Sep 16, 2024 at 1:38 AM Tony Ambardar <tony.ambardar@gmail.com> wrote:
>
> Support for handling BTF data of either endianness was added in [1], but
> did not include BTF.ext data for lack of use cases. Later, support for
> static linking [2] provided a use case, but this feature and later ones
> were restricted to native-endian usage.
>
> Add support for BTF.ext handling in either endianness. Convert BTF.ext data
> to native endianness when read into memory for further processing, and
> support raw data access that restores the original byte-order for output.
> Add internal header functions for byte-swapping func, line, and core info
> records.
>
> Add new API functions btf_ext__endianness() and btf_ext__set_endianness()
> for query and setting byte-order, as already exist for BTF data.
>
> [1] 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness")
> [2] 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support")
>
> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
> ---
> tools/lib/bpf/btf.c | 280 +++++++++++++++++++++++++-------
> tools/lib/bpf/btf.h | 3 +
> tools/lib/bpf/libbpf.map | 2 +
> tools/lib/bpf/libbpf_internal.h | 30 ++++
> 4 files changed, 258 insertions(+), 57 deletions(-)
>
[...]
>
> - /* The record size needs to meet the minimum standard */
> - record_size = *(__u32 *)info;
> + /* The record size needs to meet either the minimum standard or, when
> + * handling non-native endianness data, the exact standard so as
> + * to allow safe byte-swapping.
> + */
> + record_size = is_native ? *(__u32 *)info : bswap_32(*(__u32 *)info);
> if (record_size < ext_sec->min_rec_size ||
> + (!is_native && record_size != ext_sec->rec_size) ||
ok, so the way you define min_rec_size and rec_size is actually
broken. bpf_func_info, bpf_line_info, and now also bpf_core_relo all
come from kernel UAPI header, and it could happen that libbpf is
compiled against newest definitions of them without actually
"knowing"/supporting those newer and bigger struct definitions. So
assuming that sizeof(struct bpf_line_info) is a correct expected
record size is wrong.
As it is right now, min_rec_size is *the* rec_size, so I removed that
part and updated this check to record_size != ext_sec->min_rec_size.
If we ever extend .BTF.ext records, we'll need to add a bit more code
to accomodate for that.
> record_size & 0x03) {
> pr_debug("%s section in .BTF.ext has invalid record size %u\n",
> ext_sec->desc, record_size);
> @@ -2956,7 +2968,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
> return -EINVAL;
> }
>
> - num_records = sinfo->num_info;
> + num_records = is_native ? sinfo->num_info : bswap_32(sinfo->num_info);
> if (num_records == 0) {
> pr_debug("%s section has incorrect num_records in .BTF.ext\n",
> ext_sec->desc);
> @@ -2984,64 +2996,160 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
> return 0;
> }
>
> -static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
> +/* Parse all info secs in the BTF.ext info data */
> +static int btf_ext_parse_info(struct btf_ext *btf_ext, bool is_native)
> {
> - struct btf_ext_sec_setup_param param = {
> + struct btf_ext_sec_info_param func_info = {
> .off = btf_ext->hdr->func_info_off,
> .len = btf_ext->hdr->func_info_len,
> .min_rec_size = sizeof(struct bpf_func_info_min),
> + .rec_size = sizeof(struct bpf_func_info),
> .ext_info = &btf_ext->func_info,
> .desc = "func_info"
> };
> -
> - return btf_ext_setup_info(btf_ext, ¶m);
> -}
> -
> -static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
> -{
> - struct btf_ext_sec_setup_param param = {
> + struct btf_ext_sec_info_param line_info = {
> .off = btf_ext->hdr->line_info_off,
> .len = btf_ext->hdr->line_info_len,
> .min_rec_size = sizeof(struct bpf_line_info_min),
> + .rec_size = sizeof(struct bpf_line_info),
> .ext_info = &btf_ext->line_info,
> .desc = "line_info",
> };
> -
> - return btf_ext_setup_info(btf_ext, ¶m);
> -}
> -
> -static int btf_ext_setup_core_relos(struct btf_ext *btf_ext)
> -{
> - struct btf_ext_sec_setup_param param = {
> + struct btf_ext_sec_info_param core_relo = {
> .off = btf_ext->hdr->core_relo_off,
> .len = btf_ext->hdr->core_relo_len,
> .min_rec_size = sizeof(struct bpf_core_relo),
> + .rec_size = sizeof(struct bpf_core_relo),
> .ext_info = &btf_ext->core_relo_info,
> .desc = "core_relo",
> };
[...]
>
> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
> index 4e349ad79ee6..47ee8f6ac489 100644
> --- a/tools/lib/bpf/btf.h
> +++ b/tools/lib/bpf/btf.h
> @@ -167,6 +167,9 @@ LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
> LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
> LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
> LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
> +LIBBPF_API enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext);
> +LIBBPF_API int btf_ext__set_endianness(struct btf_ext *btf_ext,
> + enum btf_endianness endian);
>
> LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
> LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 0096e483f7eb..f40ccc2946e7 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -421,6 +421,8 @@ LIBBPF_1.5.0 {
> global:
> btf__distill_base;
> btf__relocate;
> + btf_ext__endianness;
> + btf_ext__set_endianness;
> bpf_map__autoattach;
> bpf_map__set_autoattach;
> bpf_object__token_fd;
> diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
> index 8cda511a1982..1307753b49b3 100644
> --- a/tools/lib/bpf/libbpf_internal.h
> +++ b/tools/lib/bpf/libbpf_internal.h
missing #include <byteswap.h> in libbpf_internal.h, you added too late
(in the next patch). I moved that include into this patch/commit to
not break bisectability, please be careful about things like that
> @@ -484,6 +484,8 @@ struct btf_ext {
> struct btf_ext_header *hdr;
> void *data;
> };
> + void *data_swapped;
> + bool swapped_endian;
> struct btf_ext_info func_info;
> struct btf_ext_info line_info;
> struct btf_ext_info core_relo_info;
> @@ -511,6 +513,34 @@ struct bpf_line_info_min {
> __u32 line_col;
> };
>
> +/* Functions to byte-swap info records */
> +
> +typedef void (*info_rec_bswap_fn)(void *);
> +
> +static inline void bpf_func_info_bswap(struct bpf_func_info *i)
> +{
> + i->insn_off = bswap_32(i->insn_off);
> + i->type_id = bswap_32(i->type_id);
> +}
> +
> +static inline void bpf_line_info_bswap(struct bpf_line_info *i)
> +{
> + i->insn_off = bswap_32(i->insn_off);
> + i->file_name_off = bswap_32(i->file_name_off);
> + i->line_off = bswap_32(i->line_off);
> + i->line_col = bswap_32(i->line_col);
> +}
> +
> +static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
> +{
> + _Static_assert(sizeof(i->kind) == sizeof(__u32),
> + "enum bpf_core_relo_kind is not 32-bit\n");
Do we need the endline in _Static_assert() messages? And generally I
think this is a bit too paranoid to check that that enum is backed by
u32, I just dropped the assertion. This is part of kernel UAPI, it
shouldn't change.
> + i->insn_off = bswap_32(i->insn_off);
> + i->type_id = bswap_32(i->type_id);
> + i->access_str_off = bswap_32(i->access_str_off);
> + i->kind = bswap_32(i->kind);
> +}
> +
> enum btf_field_iter_kind {
> BTF_FIELD_ITER_IDS,
> BTF_FIELD_ITER_STRS,
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH bpf-next v6 5/8] libbpf: Support opening bpf objects of either endianness
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (3 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 4/8] libbpf: Support BTF.ext loading and output in either endianness Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 6/8] libbpf: Support linking " Tony Ambardar
` (3 subsequent siblings)
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Allow bpf_object__open() to access files of either endianness, and convert
included BPF programs to native byte-order in-memory for introspection.
Loading BPF objects of non-native byte-order is still disallowed however.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/libbpf.c | 51 +++++++++++++++++++++++++++------
tools/lib/bpf/libbpf_internal.h | 11 +++++++
2 files changed, 53 insertions(+), 9 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 60b69c6aaf53..0540d2331535 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -694,6 +694,8 @@ struct bpf_object {
/* Information when doing ELF related work. Only valid if efile.elf is not NULL */
struct elf_state efile;
+ unsigned char byteorder;
+
struct btf *btf;
struct btf_ext *btf_ext;
@@ -940,6 +942,20 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
return 0;
}
+static void bpf_object_bswap_progs(struct bpf_object *obj)
+{
+ struct bpf_program *prog = obj->programs;
+ struct bpf_insn *insn;
+ int p, i;
+
+ for (p = 0; p < obj->nr_programs; p++, prog++) {
+ insn = prog->insns;
+ for (i = 0; i < prog->insns_cnt; i++, insn++)
+ bpf_insn_bswap(insn);
+ }
+ pr_debug("converted %zu BPF programs to native byte order\n", obj->nr_programs);
+}
+
static const struct btf_member *
find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
{
@@ -1506,6 +1522,7 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
+ obj->efile.ehdr = NULL;
obj->efile.symbols = NULL;
obj->efile.arena_data = NULL;
@@ -1571,6 +1588,16 @@ static int bpf_object__elf_init(struct bpf_object *obj)
goto errout;
}
+ /* Validate ELF object endianness... */
+ if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
+ ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
+ err = -LIBBPF_ERRNO__ENDIAN;
+ pr_warn("elf: '%s' has unknown byte order\n", obj->path);
+ goto errout;
+ }
+ /* and save after bpf_object_open() frees ELF data */
+ obj->byteorder = ehdr->e_ident[EI_DATA];
+
if (elf_getshdrstrndx(elf, &obj->efile.shstrndx)) {
pr_warn("elf: failed to get section names section index for %s: %s\n",
obj->path, elf_errmsg(-1));
@@ -1599,19 +1626,15 @@ static int bpf_object__elf_init(struct bpf_object *obj)
return err;
}
-static int bpf_object__check_endianness(struct bpf_object *obj)
+static bool is_native_endianness(struct bpf_object *obj)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
- return 0;
+ return obj->byteorder == ELFDATA2LSB;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
- return 0;
+ return obj->byteorder == ELFDATA2MSB;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
- pr_warn("elf: endianness mismatch in %s.\n", obj->path);
- return -LIBBPF_ERRNO__ENDIAN;
}
static int
@@ -3953,6 +3976,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
return -LIBBPF_ERRNO__FORMAT;
}
+ /* change BPF program insns to native endianness for introspection */
+ if (!is_native_endianness(obj))
+ bpf_object_bswap_progs(obj);
+
/* sort BPF programs by section name and in-section instruction offset
* for faster search
*/
@@ -7992,7 +8019,6 @@ static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf,
}
err = bpf_object__elf_init(obj);
- err = err ? : bpf_object__check_endianness(obj);
err = err ? : bpf_object__elf_collect(obj);
err = err ? : bpf_object__collect_externs(obj);
err = err ? : bpf_object_fixup_btf(obj);
@@ -8498,8 +8524,15 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch
return libbpf_err(-EINVAL);
}
- if (obj->gen_loader)
+ /* Disallow kernel loading programs of non-native endianness but
+ * permit cross-endian creation of "light skeleton".
+ */
+ if (obj->gen_loader) {
bpf_gen__init(obj->gen_loader, extra_log_level, obj->nr_programs, obj->nr_maps);
+ } else if (!is_native_endianness(obj)) {
+ pr_warn("object '%s': loading non-native endianness is unsupported\n", obj->name);
+ return libbpf_err(-LIBBPF_ERRNO__ENDIAN);
+ }
err = bpf_object_prepare_token(obj);
err = err ? : bpf_object__probe_loading(obj);
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 1307753b49b3..37477387fb5b 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -11,6 +11,7 @@
#include <stdlib.h>
#include <limits.h>
+#include <byteswap.h>
#include <errno.h>
#include <linux/err.h>
#include <fcntl.h>
@@ -618,6 +619,16 @@ static inline bool is_ldimm64_insn(struct bpf_insn *insn)
return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
}
+static inline void bpf_insn_bswap(struct bpf_insn *insn)
+{
+ __u8 tmp_reg = insn->dst_reg;
+
+ insn->dst_reg = insn->src_reg;
+ insn->src_reg = tmp_reg;
+ insn->off = bswap_16(insn->off);
+ insn->imm = bswap_32(insn->imm);
+}
+
/* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
* Original FD is not closed or altered in any other way.
* Preserves original FD value, if it's invalid (negative).
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 6/8] libbpf: Support linking bpf objects of either endianness
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (4 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 5/8] libbpf: Support opening bpf objects of " Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 7/8] libbpf: Support creating light skeleton " Tony Ambardar
` (2 subsequent siblings)
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Allow static linking object files of either endianness, checking that input
files have consistent byte-order, and setting output endianness from input.
Linking requires in-memory processing of programs, relocations, sections,
etc. in native endianness, and output conversion to target byte-order. This
is enabled by built-in ELF translation and recent BTF/BTF.ext endianness
functions. Further add local functions for swapping byte-order of sections
containing BPF insns.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/linker.c | 78 +++++++++++++++++++++++++++++++++---------
1 file changed, 62 insertions(+), 16 deletions(-)
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index 6985ab0f1ca9..81dbbdd79a7c 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -135,6 +135,7 @@ struct bpf_linker {
int fd;
Elf *elf;
Elf64_Ehdr *elf_hdr;
+ bool swapped_endian;
/* Output sections metadata */
struct dst_sec *secs;
@@ -324,13 +325,8 @@ static int init_output_elf(struct bpf_linker *linker, const char *file)
linker->elf_hdr->e_machine = EM_BPF;
linker->elf_hdr->e_type = ET_REL;
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- linker->elf_hdr->e_ident[EI_DATA] = ELFDATA2LSB;
-#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- linker->elf_hdr->e_ident[EI_DATA] = ELFDATA2MSB;
-#else
-#error "Unknown __BYTE_ORDER__"
-#endif
+ /* Set unknown ELF endianness, assign later from input files */
+ linker->elf_hdr->e_ident[EI_DATA] = ELFDATANONE;
/* STRTAB */
/* initialize strset with an empty string to conform to ELF */
@@ -541,19 +537,21 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,
const struct bpf_linker_file_opts *opts,
struct src_obj *obj)
{
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- const int host_endianness = ELFDATA2LSB;
-#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
- const int host_endianness = ELFDATA2MSB;
-#else
-#error "Unknown __BYTE_ORDER__"
-#endif
int err = 0;
Elf_Scn *scn;
Elf_Data *data;
Elf64_Ehdr *ehdr;
Elf64_Shdr *shdr;
struct src_sec *sec;
+ unsigned char obj_byteorder;
+ unsigned char link_byteorder = linker->elf_hdr->e_ident[EI_DATA];
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+ const unsigned char host_byteorder = ELFDATA2LSB;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+ const unsigned char host_byteorder = ELFDATA2MSB;
+#else
+#error "Unknown __BYTE_ORDER__"
+#endif
pr_debug("linker: adding object file '%s'...\n", filename);
@@ -579,11 +577,25 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,
pr_warn_elf("failed to get ELF header for %s", filename);
return err;
}
- if (ehdr->e_ident[EI_DATA] != host_endianness) {
+
+ /* Linker output endianness set by first input object */
+ obj_byteorder = ehdr->e_ident[EI_DATA];
+ if (obj_byteorder != ELFDATA2LSB && obj_byteorder != ELFDATA2MSB) {
+ err = -EOPNOTSUPP;
+ pr_warn("unknown byte order of ELF file %s\n", filename);
+ return err;
+ }
+ if (link_byteorder == ELFDATANONE) {
+ linker->elf_hdr->e_ident[EI_DATA] = obj_byteorder;
+ linker->swapped_endian = obj_byteorder != host_byteorder;
+ pr_debug("linker: set %s-endian output byte order\n",
+ obj_byteorder == ELFDATA2MSB ? "big" : "little");
+ } else if (link_byteorder != obj_byteorder) {
err = -EOPNOTSUPP;
- pr_warn_elf("unsupported byte order of ELF file %s", filename);
+ pr_warn("byte order mismatch with ELF file %s\n", filename);
return err;
}
+
if (ehdr->e_type != ET_REL
|| ehdr->e_machine != EM_BPF
|| ehdr->e_ident[EI_CLASS] != ELFCLASS64) {
@@ -1111,6 +1123,24 @@ static bool sec_content_is_same(struct dst_sec *dst_sec, struct src_sec *src_sec
return true;
}
+static bool is_exec_sec(struct dst_sec *sec)
+{
+ if (!sec || sec->ephemeral)
+ return false;
+ return (sec->shdr->sh_type == SHT_PROGBITS) &&
+ (sec->shdr->sh_flags & SHF_EXECINSTR);
+}
+
+static void exec_sec_bswap(void *raw_data, int size)
+{
+ const int insn_cnt = size / sizeof(struct bpf_insn);
+ struct bpf_insn *insn = raw_data;
+ int i;
+
+ for (i = 0; i < insn_cnt; i++, insn++)
+ bpf_insn_bswap(insn);
+}
+
static int extend_sec(struct bpf_linker *linker, struct dst_sec *dst, struct src_sec *src)
{
void *tmp;
@@ -1170,6 +1200,10 @@ static int extend_sec(struct bpf_linker *linker, struct dst_sec *dst, struct src
memset(dst->raw_data + dst->sec_sz, 0, dst_align_sz - dst->sec_sz);
/* now copy src data at a properly aligned offset */
memcpy(dst->raw_data + dst_align_sz, src->data->d_buf, src->shdr->sh_size);
+
+ /* convert added bpf insns to native byte-order */
+ if (linker->swapped_endian && is_exec_sec(dst))
+ exec_sec_bswap(dst->raw_data + dst_align_sz, src->shdr->sh_size);
}
dst->sec_sz = dst_final_sz;
@@ -2630,6 +2664,10 @@ int bpf_linker__finalize(struct bpf_linker *linker)
if (!sec->scn)
continue;
+ /* restore sections with bpf insns to target byte-order */
+ if (linker->swapped_endian && is_exec_sec(sec))
+ exec_sec_bswap(sec->raw_data, sec->sec_sz);
+
sec->data->d_buf = sec->raw_data;
}
@@ -2698,6 +2736,7 @@ static int emit_elf_data_sec(struct bpf_linker *linker, const char *sec_name,
static int finalize_btf(struct bpf_linker *linker)
{
+ enum btf_endianness link_endianness;
LIBBPF_OPTS(btf_dedup_opts, opts);
struct btf *btf = linker->btf;
const void *raw_data;
@@ -2742,6 +2781,13 @@ static int finalize_btf(struct bpf_linker *linker)
return err;
}
+ /* Set .BTF and .BTF.ext output byte order */
+ link_endianness = linker->elf_hdr->e_ident[EI_DATA] == ELFDATA2MSB ?
+ BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+ btf__set_endianness(linker->btf, link_endianness);
+ if (linker->btf_ext)
+ btf_ext__set_endianness(linker->btf_ext, link_endianness);
+
/* Emit .BTF section */
raw_data = btf__raw_data(linker->btf, &raw_sz);
if (!raw_data)
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 7/8] libbpf: Support creating light skeleton of either endianness
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (5 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 6/8] libbpf: Support linking " Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-16 8:37 ` [PATCH bpf-next v6 8/8] selftests/bpf: Support cross-endian building Tony Ambardar
2024-09-27 22:00 ` [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage patchwork-bot+netdevbpf
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Track target endianness in 'struct bpf_gen' and process in-memory data in
native byte-order, but on finalization convert the embedded loader BPF
insns to target endianness.
The light skeleton also includes a target-accessed data blob which is
heterogeneous and thus difficult to convert to target byte-order on
finalization. Add support functions to convert data to target endianness
as it is added to the blob.
Also add additional debug logging for data blob structure details and
skeleton loading.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/lib/bpf/bpf_gen_internal.h | 1 +
tools/lib/bpf/gen_loader.c | 187 ++++++++++++++++++++++---------
tools/lib/bpf/libbpf.c | 1 +
tools/lib/bpf/skel_internal.h | 3 +-
4 files changed, 139 insertions(+), 53 deletions(-)
diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h
index fdf44403ff36..6ff963a491d9 100644
--- a/tools/lib/bpf/bpf_gen_internal.h
+++ b/tools/lib/bpf/bpf_gen_internal.h
@@ -34,6 +34,7 @@ struct bpf_gen {
void *data_cur;
void *insn_start;
void *insn_cur;
+ bool swapped_endian;
ssize_t cleanup_label;
__u32 nr_progs;
__u32 nr_maps;
diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
index cf3323fd47b8..8a2b0f62d91d 100644
--- a/tools/lib/bpf/gen_loader.c
+++ b/tools/lib/bpf/gen_loader.c
@@ -401,6 +401,15 @@ int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps)
opts->insns_sz = gen->insn_cur - gen->insn_start;
opts->data = gen->data_start;
opts->data_sz = gen->data_cur - gen->data_start;
+
+ /* use target endianness for embedded loader */
+ if (gen->swapped_endian) {
+ struct bpf_insn *insn = (struct bpf_insn *)opts->insns;
+ int insn_cnt = opts->insns_sz / sizeof(struct bpf_insn);
+
+ for (i = 0; i < insn_cnt; i++)
+ bpf_insn_bswap(insn++);
+ }
}
return gen->error;
}
@@ -414,6 +423,28 @@ void bpf_gen__free(struct bpf_gen *gen)
free(gen);
}
+/*
+ * Fields of bpf_attr are set to values in native byte-order before being
+ * written to the target-bound data blob, and may need endian conversion.
+ * This macro allows providing the correct value in situ more simply than
+ * writing a separate converter for *all fields* of *all records* included
+ * in union bpf_attr. Note that sizeof(rval) should match the assignment
+ * target to avoid runtime problems.
+ */
+#define tgt_endian(rval) ({ \
+ typeof(rval) _val = (rval); \
+ if (gen->swapped_endian) { \
+ switch (sizeof(_val)) { \
+ case 1: break; \
+ case 2: _val = bswap_16(_val); break; \
+ case 4: _val = bswap_32(_val); break; \
+ case 8: _val = bswap_64(_val); break; \
+ default: pr_warn("unsupported bswap size!\n"); \
+ } \
+ } \
+ _val; \
+})
+
void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data,
__u32 btf_raw_size)
{
@@ -422,11 +453,12 @@ void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data,
union bpf_attr attr;
memset(&attr, 0, attr_size);
- pr_debug("gen: load_btf: size %d\n", btf_raw_size);
btf_data = add_data(gen, btf_raw_data, btf_raw_size);
- attr.btf_size = btf_raw_size;
+ attr.btf_size = tgt_endian(btf_raw_size);
btf_load_attr = add_data(gen, &attr, attr_size);
+ pr_debug("gen: load_btf: off %d size %d, attr: off %d size %d\n",
+ btf_data, btf_raw_size, btf_load_attr, attr_size);
/* populate union bpf_attr with user provided log details */
move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_level), 4,
@@ -457,28 +489,29 @@ void bpf_gen__map_create(struct bpf_gen *gen,
union bpf_attr attr;
memset(&attr, 0, attr_size);
- attr.map_type = map_type;
- attr.key_size = key_size;
- attr.value_size = value_size;
- attr.map_flags = map_attr->map_flags;
- attr.map_extra = map_attr->map_extra;
+ attr.map_type = tgt_endian(map_type);
+ attr.key_size = tgt_endian(key_size);
+ attr.value_size = tgt_endian(value_size);
+ attr.map_flags = tgt_endian(map_attr->map_flags);
+ attr.map_extra = tgt_endian(map_attr->map_extra);
if (map_name)
libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name));
- attr.numa_node = map_attr->numa_node;
- attr.map_ifindex = map_attr->map_ifindex;
- attr.max_entries = max_entries;
- attr.btf_key_type_id = map_attr->btf_key_type_id;
- attr.btf_value_type_id = map_attr->btf_value_type_id;
-
- pr_debug("gen: map_create: %s idx %d type %d value_type_id %d\n",
- attr.map_name, map_idx, map_type, attr.btf_value_type_id);
+ attr.numa_node = tgt_endian(map_attr->numa_node);
+ attr.map_ifindex = tgt_endian(map_attr->map_ifindex);
+ attr.max_entries = tgt_endian(max_entries);
+ attr.btf_key_type_id = tgt_endian(map_attr->btf_key_type_id);
+ attr.btf_value_type_id = tgt_endian(map_attr->btf_value_type_id);
map_create_attr = add_data(gen, &attr, attr_size);
- if (attr.btf_value_type_id)
+ pr_debug("gen: map_create: %s idx %d type %d value_type_id %d, attr: off %d size %d\n",
+ map_name, map_idx, map_type, map_attr->btf_value_type_id,
+ map_create_attr, attr_size);
+
+ if (map_attr->btf_value_type_id)
/* populate union bpf_attr with btf_fd saved in the stack earlier */
move_stack2blob(gen, attr_field(map_create_attr, btf_fd), 4,
stack_off(btf_fd));
- switch (attr.map_type) {
+ switch (map_type) {
case BPF_MAP_TYPE_ARRAY_OF_MAPS:
case BPF_MAP_TYPE_HASH_OF_MAPS:
move_stack2blob(gen, attr_field(map_create_attr, inner_map_fd), 4,
@@ -498,8 +531,8 @@ void bpf_gen__map_create(struct bpf_gen *gen,
/* emit MAP_CREATE command */
emit_sys_bpf(gen, BPF_MAP_CREATE, map_create_attr, attr_size);
debug_ret(gen, "map_create %s idx %d type %d value_size %d value_btf_id %d",
- attr.map_name, map_idx, map_type, value_size,
- attr.btf_value_type_id);
+ map_name, map_idx, map_type, value_size,
+ map_attr->btf_value_type_id);
emit_check_err(gen);
/* remember map_fd in the stack, if successful */
if (map_idx < 0) {
@@ -784,12 +817,12 @@ static void emit_relo_ksym_typeless(struct bpf_gen *gen,
emit_ksym_relo_log(gen, relo, kdesc->ref);
}
-static __u32 src_reg_mask(void)
+static __u32 src_reg_mask(struct bpf_gen *gen)
{
-#if defined(__LITTLE_ENDIAN_BITFIELD)
- return 0x0f; /* src_reg,dst_reg,... */
-#elif defined(__BIG_ENDIAN_BITFIELD)
- return 0xf0; /* dst_reg,src_reg,... */
+#if defined(__LITTLE_ENDIAN_BITFIELD) /* src_reg,dst_reg,... */
+ return gen->swapped_endian ? 0xf0 : 0x0f;
+#elif defined(__BIG_ENDIAN_BITFIELD) /* dst_reg,src_reg,... */
+ return gen->swapped_endian ? 0x0f : 0xf0;
#else
#error "Unsupported bit endianness, cannot proceed"
#endif
@@ -840,7 +873,7 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo,
emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3));
clear_src_reg:
/* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
- reg_mask = src_reg_mask();
+ reg_mask = src_reg_mask(gen);
emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
@@ -931,48 +964,94 @@ static void cleanup_relos(struct bpf_gen *gen, int insns)
cleanup_core_relo(gen);
}
+/* Convert func, line, and core relo info blobs to target endianness */
+static void info_blob_bswap(struct bpf_gen *gen, int func_info, int line_info,
+ int core_relos, struct bpf_prog_load_opts *load_attr)
+{
+ struct bpf_func_info *fi = gen->data_start + func_info;
+ struct bpf_line_info *li = gen->data_start + line_info;
+ struct bpf_core_relo *cr = gen->data_start + core_relos;
+ int i;
+
+ for (i = 0; i < load_attr->func_info_cnt; i++)
+ bpf_func_info_bswap(fi++);
+
+ for (i = 0; i < load_attr->line_info_cnt; i++)
+ bpf_line_info_bswap(li++);
+
+ for (i = 0; i < gen->core_relo_cnt; i++)
+ bpf_core_relo_bswap(cr++);
+}
+
void bpf_gen__prog_load(struct bpf_gen *gen,
enum bpf_prog_type prog_type, const char *prog_name,
const char *license, struct bpf_insn *insns, size_t insn_cnt,
struct bpf_prog_load_opts *load_attr, int prog_idx)
{
+ int func_info_tot_sz = load_attr->func_info_cnt *
+ load_attr->func_info_rec_size;
+ int line_info_tot_sz = load_attr->line_info_cnt *
+ load_attr->line_info_rec_size;
+ int core_relo_tot_sz = gen->core_relo_cnt *
+ sizeof(struct bpf_core_relo);
int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos;
int attr_size = offsetofend(union bpf_attr, core_relo_rec_size);
union bpf_attr attr;
memset(&attr, 0, attr_size);
- pr_debug("gen: prog_load: type %d insns_cnt %zd progi_idx %d\n",
- prog_type, insn_cnt, prog_idx);
/* add license string to blob of bytes */
license_off = add_data(gen, license, strlen(license) + 1);
/* add insns to blob of bytes */
insns_off = add_data(gen, insns, insn_cnt * sizeof(struct bpf_insn));
+ pr_debug("gen: prog_load: prog_idx %d type %d insn off %d insns_cnt %zd license off %d\n",
+ prog_idx, prog_type, insns_off, insn_cnt, license_off);
- attr.prog_type = prog_type;
- attr.expected_attach_type = load_attr->expected_attach_type;
- attr.attach_btf_id = load_attr->attach_btf_id;
- attr.prog_ifindex = load_attr->prog_ifindex;
- attr.kern_version = 0;
- attr.insn_cnt = (__u32)insn_cnt;
- attr.prog_flags = load_attr->prog_flags;
-
- attr.func_info_rec_size = load_attr->func_info_rec_size;
- attr.func_info_cnt = load_attr->func_info_cnt;
- func_info = add_data(gen, load_attr->func_info,
- attr.func_info_cnt * attr.func_info_rec_size);
+ /* convert blob insns to target endianness */
+ if (gen->swapped_endian) {
+ struct bpf_insn *insn = gen->data_start + insns_off;
+ int i;
- attr.line_info_rec_size = load_attr->line_info_rec_size;
- attr.line_info_cnt = load_attr->line_info_cnt;
- line_info = add_data(gen, load_attr->line_info,
- attr.line_info_cnt * attr.line_info_rec_size);
+ for (i = 0; i < insn_cnt; i++, insn++)
+ bpf_insn_bswap(insn);
+ }
- attr.core_relo_rec_size = sizeof(struct bpf_core_relo);
- attr.core_relo_cnt = gen->core_relo_cnt;
- core_relos = add_data(gen, gen->core_relos,
- attr.core_relo_cnt * attr.core_relo_rec_size);
+ attr.prog_type = tgt_endian(prog_type);
+ attr.expected_attach_type = tgt_endian(load_attr->expected_attach_type);
+ attr.attach_btf_id = tgt_endian(load_attr->attach_btf_id);
+ attr.prog_ifindex = tgt_endian(load_attr->prog_ifindex);
+ attr.kern_version = 0;
+ attr.insn_cnt = tgt_endian((__u32)insn_cnt);
+ attr.prog_flags = tgt_endian(load_attr->prog_flags);
+
+ attr.func_info_rec_size = tgt_endian(load_attr->func_info_rec_size);
+ attr.func_info_cnt = tgt_endian(load_attr->func_info_cnt);
+ func_info = add_data(gen, load_attr->func_info, func_info_tot_sz);
+ pr_debug("gen: prog_load: func_info: off %d cnt %d rec size %d\n",
+ func_info, load_attr->func_info_cnt,
+ load_attr->func_info_rec_size);
+
+ attr.line_info_rec_size = tgt_endian(load_attr->line_info_rec_size);
+ attr.line_info_cnt = tgt_endian(load_attr->line_info_cnt);
+ line_info = add_data(gen, load_attr->line_info, line_info_tot_sz);
+ pr_debug("gen: prog_load: line_info: off %d cnt %d rec size %d\n",
+ line_info, load_attr->line_info_cnt,
+ load_attr->line_info_rec_size);
+
+ attr.core_relo_rec_size = tgt_endian((__u32)sizeof(struct bpf_core_relo));
+ attr.core_relo_cnt = tgt_endian(gen->core_relo_cnt);
+ core_relos = add_data(gen, gen->core_relos, core_relo_tot_sz);
+ pr_debug("gen: prog_load: core_relos: off %d cnt %d rec size %zd\n",
+ core_relos, gen->core_relo_cnt,
+ sizeof(struct bpf_core_relo));
+
+ /* convert all info blobs to target endianness */
+ if (gen->swapped_endian)
+ info_blob_bswap(gen, func_info, line_info, core_relos, load_attr);
libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
prog_load_attr = add_data(gen, &attr, attr_size);
+ pr_debug("gen: prog_load: attr: off %d size %d\n",
+ prog_load_attr, attr_size);
/* populate union bpf_attr with a pointer to license */
emit_rel_store(gen, attr_field(prog_load_attr, license), license_off);
@@ -1040,7 +1119,6 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
int zero = 0;
memset(&attr, 0, attr_size);
- pr_debug("gen: map_update_elem: idx %d\n", map_idx);
value = add_data(gen, pvalue, value_size);
key = add_data(gen, &zero, sizeof(zero));
@@ -1068,6 +1146,8 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
map_update_attr = add_data(gen, &attr, attr_size);
+ pr_debug("gen: map_update_elem: idx %d, value: off %d size %d, attr: off %d size %d\n",
+ map_idx, value, value_size, map_update_attr, attr_size);
move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
blob_fd_array_off(gen, map_idx));
emit_rel_store(gen, attr_field(map_update_attr, key), key);
@@ -1084,14 +1164,16 @@ void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slo
int attr_size = offsetofend(union bpf_attr, flags);
int map_update_attr, key;
union bpf_attr attr;
+ int tgt_slot;
memset(&attr, 0, attr_size);
- pr_debug("gen: populate_outer_map: outer %d key %d inner %d\n",
- outer_map_idx, slot, inner_map_idx);
- key = add_data(gen, &slot, sizeof(slot));
+ tgt_slot = tgt_endian(slot);
+ key = add_data(gen, &tgt_slot, sizeof(tgt_slot));
map_update_attr = add_data(gen, &attr, attr_size);
+ pr_debug("gen: populate_outer_map: outer %d key %d inner %d, attr: off %d size %d\n",
+ outer_map_idx, slot, inner_map_idx, map_update_attr, attr_size);
move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
blob_fd_array_off(gen, outer_map_idx));
emit_rel_store(gen, attr_field(map_update_attr, key), key);
@@ -1112,8 +1194,9 @@ void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx)
union bpf_attr attr;
memset(&attr, 0, attr_size);
- pr_debug("gen: map_freeze: idx %d\n", map_idx);
map_freeze_attr = add_data(gen, &attr, attr_size);
+ pr_debug("gen: map_freeze: idx %d, attr: off %d size %d\n",
+ map_idx, map_freeze_attr, attr_size);
move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4,
blob_fd_array_off(gen, map_idx));
/* emit MAP_FREEZE command */
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0540d2331535..9453a0c01337 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9129,6 +9129,7 @@ int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts)
if (!gen)
return -ENOMEM;
gen->opts = opts;
+ gen->swapped_endian = !is_native_endianness(obj);
obj->gen_loader = gen;
return 0;
}
diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h
index 0875452521e9..4d5fa079b5d6 100644
--- a/tools/lib/bpf/skel_internal.h
+++ b/tools/lib/bpf/skel_internal.h
@@ -351,10 +351,11 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
attr.test.ctx_size_in = opts->ctx->sz;
err = skel_sys_bpf(BPF_PROG_RUN, &attr, test_run_attr_sz);
if (err < 0 || (int)attr.test.retval < 0) {
- opts->errstr = "failed to execute loader prog";
if (err < 0) {
+ opts->errstr = "failed to execute loader prog";
set_err;
} else {
+ opts->errstr = "error returned by loader prog";
err = (int)attr.test.retval;
#ifndef __KERNEL__
errno = -err;
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v6 8/8] selftests/bpf: Support cross-endian building
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (6 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 7/8] libbpf: Support creating light skeleton " Tony Ambardar
@ 2024-09-16 8:37 ` Tony Ambardar
2024-09-27 22:00 ` [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage patchwork-bot+netdevbpf
8 siblings, 0 replies; 11+ messages in thread
From: Tony Ambardar @ 2024-09-16 8:37 UTC (permalink / raw)
To: bpf
Cc: Tony Ambardar, linux-kselftest, Andrii Nakryiko, Eduard Zingerman,
Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, Mykola Lysenko, Shuah Khan, Ilya Leoshkevich,
Quentin Monnet
Update Makefile build rules to compile BPF programs with target endianness
rather than host byte-order. With recent changes, this allows building the
full selftests/bpf suite hosted on x86_64 and targeting s390x or mips64eb
for example.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
tools/testing/selftests/bpf/Makefile | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index f04af11df8eb..5d302db43778 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -446,6 +446,7 @@ endef
IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
MENDIAN=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
+BPF_TARGET_ENDIAN=$(if $(IS_LITTLE_ENDIAN),--target=bpfel,--target=bpfeb)
ifneq ($(CROSS_COMPILE),)
CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
@@ -473,17 +474,17 @@ $(OUTPUT)/cgroup_getset_retval_hooks.o: cgroup_getset_retval_hooks.h
# $4 - binary name
define CLANG_BPF_BUILD_RULE
$(call msg,CLNG-BPF,$4,$2)
- $(Q)$(CLANG) $3 -O2 --target=bpf -c $1 -mcpu=v3 -o $2
+ $(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v3 -o $2
endef
# Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32
define CLANG_NOALU32_BPF_BUILD_RULE
$(call msg,CLNG-BPF,$4,$2)
- $(Q)$(CLANG) $3 -O2 --target=bpf -c $1 -mcpu=v2 -o $2
+ $(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v2 -o $2
endef
# Similar to CLANG_BPF_BUILD_RULE, but with cpu-v4
define CLANG_CPUV4_BPF_BUILD_RULE
$(call msg,CLNG-BPF,$4,$2)
- $(Q)$(CLANG) $3 -O2 --target=bpf -c $1 -mcpu=v4 -o $2
+ $(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v4 -o $2
endef
# Build BPF object using GCC
define GCC_BPF_BUILD_RULE
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage
2024-09-16 8:37 [PATCH bpf-next v6 0/8] libbpf, selftests/bpf: Support cross-endian usage Tony Ambardar
` (7 preceding siblings ...)
2024-09-16 8:37 ` [PATCH bpf-next v6 8/8] selftests/bpf: Support cross-endian building Tony Ambardar
@ 2024-09-27 22:00 ` patchwork-bot+netdevbpf
8 siblings, 0 replies; 11+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-09-27 22:00 UTC (permalink / raw)
To: Tony Ambardar
Cc: bpf, linux-kselftest, andrii, eddyz87, ast, daniel, martin.lau,
song, yonghong.song, john.fastabend, kpsingh, sdf, haoluo, jolsa,
mykolal, shuah, iii, qmo
Hello:
This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:
On Mon, 16 Sep 2024 01:37:39 -0700 you wrote:
> Hello all,
>
> This patch series targets a long-standing BPF usability issue - the lack
> of general cross-compilation support - by enabling cross-endian usage of
> libbpf and bpftool, as well as supporting cross-endian build targets for
> selftests/bpf.
>
> [...]
Here is the summary with links:
- [bpf-next,v6,1/8] libbpf: Improve log message formatting
https://git.kernel.org/bpf/bpf-next/c/86eb7eb4fbfc
- [bpf-next,v6,2/8] libbpf: Fix header comment typos for BTF.ext
https://git.kernel.org/bpf/bpf-next/c/4977b35bfd4b
- [bpf-next,v6,3/8] libbpf: Fix output .symtab byte-order during linking
https://git.kernel.org/bpf/bpf-next/c/a91c9b9697ff
- [bpf-next,v6,4/8] libbpf: Support BTF.ext loading and output in either endianness
https://git.kernel.org/bpf/bpf-next/c/14a76da84b18
- [bpf-next,v6,5/8] libbpf: Support opening bpf objects of either endianness
https://git.kernel.org/bpf/bpf-next/c/f9292d6570d5
- [bpf-next,v6,6/8] libbpf: Support linking bpf objects of either endianness
https://git.kernel.org/bpf/bpf-next/c/ab4184fd1bb8
- [bpf-next,v6,7/8] libbpf: Support creating light skeleton of either endianness
https://git.kernel.org/bpf/bpf-next/c/a1cb9abcfec4
- [bpf-next,v6,8/8] selftests/bpf: Support cross-endian building
https://git.kernel.org/bpf/bpf-next/c/4fd5a501e1d0
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 11+ messages in thread