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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Fri, 28 Apr 2023 13:32:53 +0200
Message-ID: <CAJZ5v0iWUV=V5zqUp7DdJhR2FZiSOpbUUg7nuRg7N_xt4e0ETQ@mail.gmail.com>
Subject: Re: [PATCH RFC 07/43] x86/acpi: Adapt assembly for PIE support
To:     Hou Wenlong <houwenlong.hwl@antgroup.com>
Cc:     linux-kernel@vger.kernel.org,
        Thomas Garnier <thgarnie@chromium.org>,
        Lai Jiangshan <jiangshan.ljs@antgroup.com>,
        Kees Cook <keescook@chromium.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-pm@vger.kernel.org,
        linux-acpi@vger.kernel.org
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On Fri, Apr 28, 2023 at 11:52 AM Hou Wenlong
<houwenlong.hwl@antgroup.com> wrote:
>
> From: Thomas Garnier <thgarnie@chromium.org>
>
> From: Thomas Garnier <thgarnie@chromium.org>
>
> Change the assembly code to use only relative references of symbols for the
> kernel to be PIE compatible.
>
> Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> Cc: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> Cc: Kees Cook <keescook@chromium.org>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
>  arch/x86/kernel/acpi/wakeup_64.S | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
> index d5d8a352eafa..fe688bd87d72 100644
> --- a/arch/x86/kernel/acpi/wakeup_64.S
> +++ b/arch/x86/kernel/acpi/wakeup_64.S
> @@ -17,7 +17,7 @@
>          * Hooray, we are in Long 64-bit mode (but still running in low memory)
>          */
>  SYM_FUNC_START(wakeup_long64)
> -       movq    saved_magic, %rax
> +       movq    saved_magic(%rip), %rax
>         movq    $0x123456789abcdef0, %rdx
>         cmpq    %rdx, %rax
>         je      2f
> @@ -33,14 +33,14 @@ SYM_FUNC_START(wakeup_long64)
>         movw    %ax, %es
>         movw    %ax, %fs
>         movw    %ax, %gs
> -       movq    saved_rsp, %rsp
> +       movq    saved_rsp(%rip), %rsp
>
> -       movq    saved_rbx, %rbx
> -       movq    saved_rdi, %rdi
> -       movq    saved_rsi, %rsi
> -       movq    saved_rbp, %rbp
> +       movq    saved_rbx(%rip), %rbx
> +       movq    saved_rdi(%rip), %rdi
> +       movq    saved_rsi(%rip), %rsi
> +       movq    saved_rbp(%rip), %rbp
>
> -       movq    saved_rip, %rax
> +       movq    saved_rip(%rip), %rax
>         ANNOTATE_RETPOLINE_SAFE
>         jmp     *%rax
>  SYM_FUNC_END(wakeup_long64)
> @@ -51,7 +51,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
>         xorl    %eax, %eax
>         call    save_processor_state
>
> -       movq    $saved_context, %rax
> +       leaq    saved_context(%rip), %rax
>         movq    %rsp, pt_regs_sp(%rax)
>         movq    %rbp, pt_regs_bp(%rax)
>         movq    %rsi, pt_regs_si(%rax)
> @@ -70,13 +70,14 @@ SYM_FUNC_START(do_suspend_lowlevel)
>         pushfq
>         popq    pt_regs_flags(%rax)
>
> -       movq    $.Lresume_point, saved_rip(%rip)
> +       leaq    .Lresume_point(%rip), %rax
> +       movq    %rax, saved_rip(%rip)
>
> -       movq    %rsp, saved_rsp
> -       movq    %rbp, saved_rbp
> -       movq    %rbx, saved_rbx
> -       movq    %rdi, saved_rdi
> -       movq    %rsi, saved_rsi
> +       movq    %rsp, saved_rsp(%rip)
> +       movq    %rbp, saved_rbp(%rip)
> +       movq    %rbx, saved_rbx(%rip)
> +       movq    %rdi, saved_rdi(%rip)
> +       movq    %rsi, saved_rsi(%rip)
>
>         addq    $8, %rsp
>         movl    $3, %edi
> @@ -88,7 +89,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
>         .align 4
>  .Lresume_point:
>         /* We don't restore %rax, it must be 0 anyway */
> -       movq    $saved_context, %rax
> +       leaq    saved_context(%rip), %rax
>         movq    saved_context_cr4(%rax), %rbx
>         movq    %rbx, %cr4
>         movq    saved_context_cr3(%rax), %rbx
> --
> 2.31.1
>