Re: [PATCH] bpf: Fix undeclared function 'barrier_nospec' warning

[Daniel Borkmann]

On 2/22/23 9:24 AM, Viresh Kumar wrote:
> Add the missing header for architectures that don't define
> the barrier_nospec() macro. The nospec.h header is added after the
> inclusion of barrier.h to avoid redefining the macro for architectures
> that already define barrier_nospec() in their respective barrier.h
> headers.
>
> Fixes: 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()")
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
> Linus's master branch fails currently to build for arm64 without this commit.
>
>   kernel/bpf/core.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index 933869983e2a..92aeb388e422 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -38,6 +38,8 @@
>   #include <linux/memcontrol.h>
>   
>   #include <asm/barrier.h>
> +#include <linux/nospec.h>
> +

nit: The asm/barrier.h include could have just been removed. linux/nospec.h
internally includes asm/barrier.h already.

>   #include <asm/unaligned.h>
>   
>   /* Registers */