Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] include/linux/bpf.h - fix missing prototype warnings...
To:     valdis.kletnieks@vt.edu, Alexei Starovoitov <ast@kernel.org>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <6349.1548741865@turing-police.cc.vt.edu>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <5ff21ff7-fd7e-5e90-86a6-d06f9ab4fa3d@iogearbox.net>
Date:   Thu, 31 Jan 2019 10:39:02 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.3.0
MIME-Version: 1.0
In-Reply-To: <6349.1548741865@turing-police.cc.vt.edu>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 01/29/2019 07:04 AM, valdis.kletnieks@vt.edu 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@vt.edu>

Applied all 3 to bpf-next, thanks Valdis!

> 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);
> +

(I moved these to include/linux/filter.h while applying where we have all the
 other prototypes from JIT core already.)

>  #ifdef CONFIG_BPF_SYSCALL
>  DECLARE_PER_CPU(int, bpf_prog_active);
>  
>