MIME-Version: 1.0
References: <20211110100102.250793167@infradead.org> <20211110101325.186049322@infradead.org>
In-Reply-To: <20211110101325.186049322@infradead.org>
From:   Lai Jiangshan <jiangshanlai+lkml@gmail.com>
Date:   Fri, 19 Nov 2021 16:00:34 +0800
Message-ID: <CAJhGHyCG05CxdnFmMU=UkOEZ-bkS8FMdMDaZfbhagbx7vsfd6g@mail.gmail.com>
Subject: Re: [PATCH v2 05/23] x86,entry_64: Remove .fixup usage
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>, mbenes@suse.cz
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, Nov 10, 2021 at 6:19 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Place the anonymous .fixup code at the tail of the regular functions.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

> ---
>  arch/x86/entry/entry_64.S |   13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -735,13 +735,9 @@ SYM_FUNC_START(asm_load_gs_index)
>         swapgs
>         FRAME_END
>         ret
> -SYM_FUNC_END(asm_load_gs_index)
> -EXPORT_SYMBOL(asm_load_gs_index)
>
> -       _ASM_EXTABLE(.Lgs_change, .Lbad_gs)
> -       .section .fixup, "ax"
>         /* running with kernelgs */
> -SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
> +.Lbad_gs:
>         swapgs                                  /* switch back to user gs */
>  .macro ZAP_GS
>         /* This can't be a string because the preprocessor needs to see it. */
> @@ -752,8 +748,11 @@ SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
>         xorl    %eax, %eax
>         movl    %eax, %gs
>         jmp     2b
> -SYM_CODE_END(.Lbad_gs)
> -       .previous
> +
> +       _ASM_EXTABLE(.Lgs_change, .Lbad_gs)
> +
> +SYM_FUNC_END(asm_load_gs_index)
> +EXPORT_SYMBOL(asm_load_gs_index)
>
>  #ifdef CONFIG_XEN_PV
>  /*
>
>