On Mon, Sep 16, 2024 at 2:18 AM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> 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
I found it a bit annoying that bpf_helper_defs.h uses
__bpf_fastcall
static __u32 ....
format, while in vmlinux we have single-line (and yeah, note that I
put extern in front)
extern __bpf_fastcall __u32 ...
So I slightly modified bpf_doc.py with my weak Python-fu:
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index db50c8d7d112..f98933a5d38c 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -871,9 +871,10 @@ class PrinterHelpers(Printer):
print(' *{}{}'.format(' \t' if line else '', line))
print(' */')
+ print('static ', end='')
if helper.attrs:
- print(" ".join(helper.attrs))
- print('static %s %s(* const %s)(' % (self.map_type(proto['ret_type']),
+ print('%s ' % (" ".join(helper.attrs)), end='')
+ print('%s %s(* const %s)(' % (self.map_type(proto['ret_type']),
proto['ret_star'],
proto['name']), end='')
comma = ''
for i, a in enumerate(proto['args']):
But now I have:
static __bpf_fastcall __u32 (* const bpf_get_smp_processor_id)(void) =
(void *) 8;
and
extern __bpf_fastcall void *bpf_rdonly_cast(const void *obj__ign, u32
btf_id__k) __weak __ksym;
and that makes me a touch happier. I hope you don't mind.
> 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@xxxxxxxxx>
> ---
> scripts/bpf_doc.py | 50 ++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 48 insertions(+), 2 deletions(-)
>
Looks good to me, and I'm not sure there is anything too controversial
here, so I went ahead and applied to bpf-next, thanks.
