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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Fri, 4 Nov 2022 14:12:43 -0700
Message-ID: <CAEf4BzaU+jiCQy7g4N0UuifL0TcdEY4Z_5_3MHiOwZhFzKFFFg@mail.gmail.com>
Subject: Re: [PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.
To:     Kuniyuki Iwashima <kuniyu@amazon.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Akihiro HARAI <jharai0815@gmail.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Kuniyuki Iwashima <kuni1840@gmail.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org
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On Mon, Oct 31, 2022 at 2:57 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
>
> Add the same change for ARM64 as done in the commit 9440c4294160
> ("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
> make sure all syscalls see 'struct pt_regs' definition and resulted
> BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
> actual struct.
>
> Without this patch, the BPF verifier refuses to load a tracing prog
> which accesses pt_regs.
>
>   bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES
>
> With this patch, we can see the correct error, which saves us time
> in debugging the prog.
>
>   bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
>   bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP
>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
> ---

Some of these problems will be mitigated by [0], but still good to
have completely types if possible. LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

  [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=691488&state=*

> Note the cited commit only exists in the tip tree for now.
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=9440c42941606af4c379afa3cf8624f0dc43a629
> ---
>  arch/arm64/include/asm/syscall_wrapper.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
> index b383b4802a7b..d30217c21eff 100644
> --- a/arch/arm64/include/asm/syscall_wrapper.h
> +++ b/arch/arm64/include/asm/syscall_wrapper.h
> @@ -8,7 +8,7 @@
>  #ifndef __ASM_SYSCALL_WRAPPER_H
>  #define __ASM_SYSCALL_WRAPPER_H
>
> -struct pt_regs;
> +#include <asm/ptrace.h>
>
>  #define SC_ARM64_REGS_TO_ARGS(x, ...)                          \
>         __MAP(x,__SC_ARGS                                       \
> --
> 2.30.2
>