Re: [PATCH] include/linux/bpf.h - fix missing prototype warnings...

[Song Liu]

On Mon, Jan 28, 2019 at 10:05 PM <valdis.kletnieks@xxxxxx> wrote:
>
> Compiling with W=1 generates warnings:
>
>   CC      kernel/bpf/core.o
> kernel/bpf/core.c:721:12: warning: no previous prototype for ?bpf_jit_alloc_exec_limit? [-Wmissing-prototypes]
>   721 | u64 __weak bpf_jit_alloc_exec_limit(void)
>       |            ^~~~~~~~~~~~~~~~~~~~~~~~
> kernel/bpf/core.c:757:14: warning: no previous prototype for ?bpf_jit_alloc_exec? [-Wmissing-prototypes]
>   757 | void *__weak bpf_jit_alloc_exec(unsigned long size)
>       |              ^~~~~~~~~~~~~~~~~~
> kernel/bpf/core.c:762:13: warning: no previous prototype for ?bpf_jit_free_exec? [-Wmissing-prototypes]
>   762 | void __weak bpf_jit_free_exec(void *addr)
>       |             ^~~~~~~~~~~~~~~~~
>
> All three are weak functions that archs can override, although none do so
> currently.  Provide prototypes for when a new arch provides its own.
>
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>

Acked-by: Song Liu <songliubraving@xxxxxx>

>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 3851529062ec..99e55313123f 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -472,6 +472,10 @@ _out:                                                      \
>  #define BPF_PROG_RUN_ARRAY_CHECK(array, ctx, func)     \
>         __BPF_PROG_RUN_ARRAY(array, ctx, func, true)
>
> +u64 __weak bpf_jit_alloc_exec_limit(void);
> +void *__weak bpf_jit_alloc_exec(unsigned long size);
> +void __weak bpf_jit_free_exec(void *addr);
> +
>  #ifdef CONFIG_BPF_SYSCALL
>  DECLARE_PER_CPU(int, bpf_prog_active);
>
>