Re: [PATCH 09/14] x86/ibt: Implement IBT+

[Alexei Starovoitov]

On Fri, Sep 27, 2024 at 12:50 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -555,6 +555,8 @@ static int emit_patch(u8 **pprog, void *
>
>  static int emit_call(u8 **pprog, void *func, void *ip)
>  {
> +       if (is_endbr(func))
> +               func += ENDBR_INSN_SIZE;
>         return emit_patch(pprog, func, ip, 0xE8);
>  }
>
> @@ -562,11 +564,13 @@ static int emit_rsb_call(u8 **pprog, voi
>  {
>         OPTIMIZER_HIDE_VAR(func);
>         ip += x86_call_depth_emit_accounting(pprog, func, ip);
> -       return emit_patch(pprog, func, ip, 0xE8);
> +       return emit_call(pprog, func, ip);
>  }
>
>  static int emit_jump(u8 **pprog, void *func, void *ip)
>  {
> +       if (is_endbr(func))
> +               func += ENDBR_INSN_SIZE;
>         return emit_patch(pprog, func, ip, 0xE9);
>  }

Makes sense, but it feels like it's fixing the existing bug
that we somehow didn't notice earlier?