Merge branch 'bpf_fastcall-attribute-in-vmlinux-h-and-bpf_helper_defs-h'

Browse source

Eduard Zingerman says:

====================
'bpf_fastcall' attribute in vmlinux.h and bpf_helper_defs.h

The goal of this patch-set is to reflect attribute bpf_fastcall
for supported helpers and kfuncs in generated header files.
For helpers this requires a tweak for scripts/bpf_doc.py and an update
to uapi/linux/bpf.h doc-comment.
For kfuncs this requires:
- introduction of a new KF_FASTCALL flag;
- modification to pahole to read kfunc flags and generate
  DECL_TAG "bpf_fastcall" for marked kfuncs;
- modification to bpftool to scan for DECL_TAG "bpf_fastcall"
  presence.

In both cases the following helper macro is defined in the generated
header:

    #ifndef __bpf_fastcall
    #if __has_attribute(bpf_fastcall)
    #define __bpf_fastcall __attribute__((bpf_fastcall))
    #else
    #define __bpf_fastcall
    #endif
    #endif

And is used to mark appropriate function prototypes. More information
about bpf_fastcall attribute could be found in [1] and [2].

Modifications to pahole are submitted separately.

[1] LLVM source tree commit:
    64e464349bfc ("[BPF] introduce __attribute__((bpf_fastcall))")

[2] Linux kernel tree commit (note: feature was renamed from
    no_caller_saved_registers to bpf_fastcall after this commit):
    52839f31ce ("Merge branch 'no_caller_saved_registers-attribute-for-helper-calls'")
====================

Link: https://lore.kernel.org/r/20240916091712.2929279-1-eddyz87@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Andrii Nakryiko 2024-09-27 14:54:22 -07:00 • committed by Alexei Starovoitov

parent d1334e88e1 bf7ce5416f

commit 904181b334

7 changed files with 146 additions and 19 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

1

include/linux/btf.h

View file

2

include/uapi/linux/bpf.h

View file

4

kernel/bpf/helpers.c

View file

5

kernel/bpf/verifier.c

View file

53

scripts/bpf_doc.py

View file

98

tools/bpf/bpftool/btf.c

View file

2

tools/include/uapi/linux/bpf.h

View file