'bpf_fastcall' attribute in vmlinux.h and bpf_helper_defs.h #7736
+144
−18
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![kernel-patches-daemon-bpf[bot]](https://avatars.githubusercontent.com/u/70728002?s=60&v=4){kind=small}
|
Upstream branch: 5277d13 |
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
from
83110c8
to
15c4059
Compare
Allow a new optional 'Attributes' section to be specified for helper
functions description, e.g.:
* u32 bpf_get_smp_processor_id(void)
* ...
* Return
* ...
* Attributes
* __bpf_fastcall
*
Generated header for the example above:
#ifndef __bpf_fastcall
#if __has_attribute(__bpf_fastcall)
#define __bpf_fastcall __attribute__((bpf_fastcall))
#else
#define __bpf_fastcall
#endif
#endif
...
__bpf_fastcall
static __u32 (* const bpf_get_smp_processor_id)(void) = (void *) 8;
The following rules apply:
- when present, section must follow 'Return' section;
- attribute names are specified on the line following 'Attribute'
keyword;
- attribute names are separated by spaces;
- section ends with an "empty" line (" *\n").
Valid attribute names are recorded in the ATTRS map.
ATTRS maps shortcut attribute name to correct C syntax.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Since [1] kernel supports __bpf_fastcall attribute for helper function bpf_get_smp_processor_id(). Update uapi definition for this helper in order to have this attribute in the generated bpf_helper_defs.h [1] commit 91b7fbf ("bpf, x86, riscv, arm: no_caller_saved_registers for bpf_get_smp_processor_id()") Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
In order to allow pahole add btf_decl_tag("bpf_fastcall") for kfuncs
supporting bpf_fastcall, mark such functions with KF_FASTCALL in
id_set8 objects.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Generate __attribute__((bpf_fastcall)) for kfuncs marked with
"bpf_fastcall" decl tag. E.g. for the following BTF:
$ bpftool btf dump file vmlinux
...
[A] FUNC 'bpf_rdonly_cast' type_id=...
...
[B] DECL_TAG 'bpf_kfunc' type_id=A component_idx=-1
[C] DECL_TAG 'bpf_fastcall' type_id=A component_idx=-1
Generate the following vmlinux.h:
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
...
#ifndef __bpf_fastcall
#if __has_attribute(bpf_fastcall)
#define __bpf_fastcall __attribute__((bpf_fastcall))
#else
#define __bpf_fastcall
#endif
#endif
...
__bpf_fastcall extern void *bpf_rdonly_cast(...) ...;
The "bpf_fastcall" / "bpf_kfunc" tags pair would generated by pahole
when constructing vmlinux BTF.
While at it, sort printed kfuncs by name for better vmlinux.h
stability.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
|
Upstream branch: 8826498 |
kernel-patches-daemon-bpf
bot
force-pushed
the
series/890618=>bpf-next
branch
from
fceb5da
to
ffd99d0
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: 'bpf_fastcall' attribute in vmlinux.h and bpf_helper_defs.h
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=890618