2019-01-29 06:05:15

by Valdis Klētnieks

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

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 <[email protected]>

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);

2019-01-29 07:10:36

by Song Liu

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

On Mon, Jan 28, 2019 at 10:05 PM <[email protected]> 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 <[email protected]>

Acked-by: Song Liu <[email protected]>

>
> 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);
>
>

2019-01-31 09:39:31

by Daniel Borkmann

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

On 01/29/2019 07:04 AM, [email protected] 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 <[email protected]>

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);
>
>