netdev - Re: [PATCH bpf-next 3/6] bpf, x64: clean up retpoline emission slightly

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Date:   Mon, 14 May 2018 10:42:44 -0700
From:   Y Song <ys114321@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Alexei Starovoitov <alexei.starovoitov@...il.com>,
        netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH bpf-next 3/6] bpf, x64: clean up retpoline emission slightly

On Sun, May 13, 2018 at 5:26 PM, Daniel Borkmann <daniel@...earbox.net> wrote:
> Make the RETPOLINE_{RA,ED}X_BPF_JIT() a bit more readable by
> cleaning up the macro, aligning comments and spacing.
>
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> ---
>  arch/x86/include/asm/nospec-branch.h | 29 ++++++++++++++---------------
>  1 file changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
> index 2cd344d..2f700a1d 100644
> --- a/arch/x86/include/asm/nospec-branch.h
> +++ b/arch/x86/include/asm/nospec-branch.h
> @@ -301,9 +301,9 @@ do {                                                                        \
>   *    jmp *%edx for x86_32
>   */
>  #ifdef CONFIG_RETPOLINE
> -#ifdef CONFIG_X86_64
> -# define RETPOLINE_RAX_BPF_JIT_SIZE    17
> -# define RETPOLINE_RAX_BPF_JIT()                               \
> +# ifdef CONFIG_X86_64
> +#  define RETPOLINE_RAX_BPF_JIT_SIZE   17
> +#  define RETPOLINE_RAX_BPF_JIT()                              \
>  do {                                                           \
>         EMIT1_off32(0xE8, 7);    /* callq do_rop */             \
>         /* spec_trap: */                                        \
> @@ -314,8 +314,8 @@ do {                                                                \
>         EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */    \
>         EMIT1(0xC3);             /* retq */                     \
>  } while (0)
> -#else
> -# define RETPOLINE_EDX_BPF_JIT()                               \
> +# else /* !CONFIG_X86_64 */
> +#  define RETPOLINE_EDX_BPF_JIT()                              \
>  do {                                                           \
>         EMIT1_off32(0xE8, 7);    /* call do_rop */              \
>         /* spec_trap: */                                        \
> @@ -326,17 +326,16 @@ do {                                                              \
>         EMIT3(0x89, 0x14, 0x24); /* mov %edx,(%esp) */          \
>         EMIT1(0xC3);             /* ret */                      \
>  } while (0)
> -#endif
> +# endif
>  #else /* !CONFIG_RETPOLINE */
> -
> -#ifdef CONFIG_X86_64
> -# define RETPOLINE_RAX_BPF_JIT_SIZE    2
> -# define RETPOLINE_RAX_BPF_JIT()                               \
> -       EMIT2(0xFF, 0xE0);       /* jmp *%rax */
> -#else
> -# define RETPOLINE_EDX_BPF_JIT()                               \
> -       EMIT2(0xFF, 0xE2) /* jmp *%edx */
> -#endif
> +# ifdef CONFIG_X86_64
> +#  define RETPOLINE_RAX_BPF_JIT_SIZE   2
> +#  define RETPOLINE_RAX_BPF_JIT()                              \
> +       EMIT2(0xFF, 0xE0);       /* jmp *%rax */
> +# else /* !CONFIG_X86_64 */
> +#  define RETPOLINE_EDX_BPF_JIT()                              \
> +       EMIT2(0xFF, 0xE2)        /* jmp *%edx */
> +# endif
>  #endif
>
>  #endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
> --
> 2.9.5
>

Acked-by: Yonghong Song <yhs@...com>