* [PATCH bpf-next v3] libbpf: add btf__load_vmlinux_btf/btf__load_module_btf
@ 2021-07-30 11:40 Hengqi Chen
2021-07-30 19:26 ` Andrii Nakryiko
0 siblings, 1 reply; 3+ messages in thread
From: Hengqi Chen @ 2021-07-30 11:40 UTC (permalink / raw)
To: bpf; +Cc: ast, daniel, andrii, yhs, john.fastabend, kafai, hengqi.chen
Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf.
btf__load_vmlinux_btf is just an alias to the existing API named
libbpf_find_kernel_btf, rename to be more precisely and consistent
with existing BTF APIs. btf__load_module_btf can be used to load
module BTF, add it for completeness. These two APIs are useful for
implementing tracing tools and introspection tools. This is part
of the effort towards libbpf 1.0. [1]
[1] https://github.com/libbpf/libbpf/issues/280
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
---
tools/lib/bpf/btf.c | 15 ++++++++++++++-
tools/lib/bpf/btf.h | 6 ++++--
tools/lib/bpf/libbpf.c | 4 ++--
tools/lib/bpf/libbpf.map | 2 ++
4 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index cafa4f6bd9b1..56e84583e283 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -4036,7 +4036,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
*/
if (d->hypot_adjust_canon)
continue;
-
+
if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
d->map[t_id] = c_id;
@@ -4410,6 +4410,11 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
* data out of it to use for target BTF.
*/
struct btf *libbpf_find_kernel_btf(void)
+{
+ return btf__load_vmlinux_btf();
+}
+
+struct btf *btf__load_vmlinux_btf(void)
{
struct {
const char *path_fmt;
@@ -4455,6 +4460,14 @@ struct btf *libbpf_find_kernel_btf(void)
return libbpf_err_ptr(-ESRCH);
}
+struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf)
+{
+ char path[80];
+
+ snprintf(path, sizeof(path), "/sys/kernel/btf/%s", module_name);
+ return btf__parse_split(path, vmlinux_btf);
+}
+
int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx)
{
int i, n, err;
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 596a42c8f4f5..6837dd116e87 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -44,6 +44,10 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b
LIBBPF_API struct btf *btf__parse_raw(const char *path);
LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
+LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
+LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
+LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
+
LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
@@ -93,8 +97,6 @@ int btf_ext__reloc_line_info(const struct btf *btf,
LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
-LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
-
LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 313883179919..cb106e8c42cb 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2680,7 +2680,7 @@ static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force)
if (!force && !obj_needs_vmlinux_btf(obj))
return 0;
- obj->btf_vmlinux = libbpf_find_kernel_btf();
+ obj->btf_vmlinux = btf__load_vmlinux_btf();
err = libbpf_get_error(obj->btf_vmlinux);
if (err) {
pr_warn("Error loading vmlinux BTF: %d\n", err);
@@ -8297,7 +8297,7 @@ int libbpf_find_vmlinux_btf_id(const char *name,
struct btf *btf;
int err;
- btf = libbpf_find_kernel_btf();
+ btf = btf__load_vmlinux_btf();
err = libbpf_get_error(btf);
if (err) {
pr_warn("vmlinux BTF is not found\n");
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 5aca3686ca5e..a2f471950213 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -380,4 +380,6 @@ LIBBPF_0.5.0 {
btf__load_into_kernel;
btf_dump__dump_type_data;
libbpf_set_strict_mode;
+ btf__load_vmlinux_btf;
+ btf__load_module_btf;
} LIBBPF_0.4.0;
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v3] libbpf: add btf__load_vmlinux_btf/btf__load_module_btf
2021-07-30 11:40 [PATCH bpf-next v3] libbpf: add btf__load_vmlinux_btf/btf__load_module_btf Hengqi Chen
@ 2021-07-30 19:26 ` Andrii Nakryiko
2021-07-31 8:42 ` Hengqi Chen
0 siblings, 1 reply; 3+ messages in thread
From: Andrii Nakryiko @ 2021-07-30 19:26 UTC (permalink / raw)
To: Hengqi Chen
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, john fastabend, Martin Lau
On Fri, Jul 30, 2021 at 4:40 AM Hengqi Chen <hengqi.chen@gmail.com> wrote:
>
> Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf.
> btf__load_vmlinux_btf is just an alias to the existing API named
> libbpf_find_kernel_btf, rename to be more precisely and consistent
> with existing BTF APIs. btf__load_module_btf can be used to load
> module BTF, add it for completeness. These two APIs are useful for
> implementing tracing tools and introspection tools. This is part
> of the effort towards libbpf 1.0. [1]
>
> [1] https://github.com/libbpf/libbpf/issues/280
I changed this to
[0] Closes: https://github.com/libbpf/libbpf/issues/280
which will close an associated Github issue when we sync sources to
Github next time. Let's see how this works in practice.
>
> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
> ---
Thanks, applied to bpf-next. But please follow up with a selftest that
would utilize this new module BTF API. It's good to have all APIs
exercised regularly. Look at test_progs.
> tools/lib/bpf/btf.c | 15 ++++++++++++++-
> tools/lib/bpf/btf.h | 6 ++++--
> tools/lib/bpf/libbpf.c | 4 ++--
> tools/lib/bpf/libbpf.map | 2 ++
> 4 files changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index cafa4f6bd9b1..56e84583e283 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -4036,7 +4036,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
> */
> if (d->hypot_adjust_canon)
> continue;
> -
> +
> if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
> d->map[t_id] = c_id;
>
> @@ -4410,6 +4410,11 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
> * data out of it to use for target BTF.
> */
> struct btf *libbpf_find_kernel_btf(void)
I switched this to __attribute__((alias("btf__load_vmlinux_btf"))); to
match what Quentin did recently. Also moved comment above to be next
to btf__load_vmlinux_btf.
> +{
> + return btf__load_vmlinux_btf();
> +}
> +
> +struct btf *btf__load_vmlinux_btf(void)
> {
> struct {
> const char *path_fmt;
[...]
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 5aca3686ca5e..a2f471950213 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -380,4 +380,6 @@ LIBBPF_0.5.0 {
> btf__load_into_kernel;
> btf_dump__dump_type_data;
> libbpf_set_strict_mode;
> + btf__load_vmlinux_btf;
> + btf__load_module_btf;
This list needs to be alphabetically sorted. I'll fix it up while
applying, but please remember it for the future.
> } LIBBPF_0.4.0;
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v3] libbpf: add btf__load_vmlinux_btf/btf__load_module_btf
2021-07-30 19:26 ` Andrii Nakryiko
@ 2021-07-31 8:42 ` Hengqi Chen
0 siblings, 0 replies; 3+ messages in thread
From: Hengqi Chen @ 2021-07-31 8:42 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, john fastabend, Martin Lau
On 7/31/21 3:26 AM, Andrii Nakryiko wrote:
> On Fri, Jul 30, 2021 at 4:40 AM Hengqi Chen <hengqi.chen@gmail.com> wrote:
>>
>> Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf.
>> btf__load_vmlinux_btf is just an alias to the existing API named
>> libbpf_find_kernel_btf, rename to be more precisely and consistent
>> with existing BTF APIs. btf__load_module_btf can be used to load
>> module BTF, add it for completeness. These two APIs are useful for
>> implementing tracing tools and introspection tools. This is part
>> of the effort towards libbpf 1.0. [1]
>>
>> [1] https://github.com/libbpf/libbpf/issues/280
>
> I changed this to
>
> [0] Closes: https://github.com/libbpf/libbpf/issues/280
>
> which will close an associated Github issue when we sync sources to
> Github next time. Let's see how this works in practice.
>
>>
>> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
>> ---
>
> Thanks, applied to bpf-next. But please follow up with a selftest that
> would utilize this new module BTF API. It's good to have all APIs
> exercised regularly. Look at test_progs.
>
Thanks, will do.
>> tools/lib/bpf/btf.c | 15 ++++++++++++++-
>> tools/lib/bpf/btf.h | 6 ++++--
>> tools/lib/bpf/libbpf.c | 4 ++--
>> tools/lib/bpf/libbpf.map | 2 ++
>> 4 files changed, 22 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
>> index cafa4f6bd9b1..56e84583e283 100644
>> --- a/tools/lib/bpf/btf.c
>> +++ b/tools/lib/bpf/btf.c
>> @@ -4036,7 +4036,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
>> */
>> if (d->hypot_adjust_canon)
>> continue;
>> -
>> +
>> if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
>> d->map[t_id] = c_id;
>>
>> @@ -4410,6 +4410,11 @@ static int btf_dedup_remap_types(struct btf_dedup *d)
>> * data out of it to use for target BTF.
>> */
>> struct btf *libbpf_find_kernel_btf(void)
>
> I switched this to __attribute__((alias("btf__load_vmlinux_btf"))); to
> match what Quentin did recently. Also moved comment above to be next
> to btf__load_vmlinux_btf.
>
OK, the alias attribute look nicer.
>> +{
>> + return btf__load_vmlinux_btf();
>> +}
>> +
>> +struct btf *btf__load_vmlinux_btf(void)
>> {
>> struct {
>> const char *path_fmt;
>
> [...]
>
>> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
>> index 5aca3686ca5e..a2f471950213 100644
>> --- a/tools/lib/bpf/libbpf.map
>> +++ b/tools/lib/bpf/libbpf.map
>> @@ -380,4 +380,6 @@ LIBBPF_0.5.0 {
>> btf__load_into_kernel;
>> btf_dump__dump_type_data;
>> libbpf_set_strict_mode;
>> + btf__load_vmlinux_btf;
>> + btf__load_module_btf;
>
> This list needs to be alphabetically sorted. I'll fix it up while
> applying, but please remember it for the future.
>
Yeah, will keep this in mind.
>> } LIBBPF_0.4.0;
>> --
>> 2.25.1
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-07-30 11:40 [PATCH bpf-next v3] libbpf: add btf__load_vmlinux_btf/btf__load_module_btf Hengqi Chen
2021-07-30 19:26 ` Andrii Nakryiko
2021-07-31 8:42 ` Hengqi Chen
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