Message-ID: <cfdb9c5a-4723-d920-511e-b57ae6c492f7@bytedance.com>
Date:   Fri, 24 Feb 2023 20:40:44 +0000
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: [External] [PATCH v2 0/5] x86-64: Remove global variables from
 boot
Content-Language: en-US
To:     Brian Gerst <brgerst@gmail.com>, linux-kernel@vger.kernel.org,
        x86@kernel.org, David Woodhouse <dwmw2@infradead.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Ingo Molnar <mingo@kernel.org>
References: <20230224154235.277350-1-brgerst@gmail.com>
From:   Usama Arif <usama.arif@bytedance.com>
In-Reply-To: <20230224154235.277350-1-brgerst@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 24/02/2023 15:42, Brian Gerst wrote:
> This is based on the parallel boot v11 series.
> 
> Remove the global variables initial_gs, initial_stack, and
> early_gdt_descr from the 64-bit boot code.  The stack, GDT, and GSBASE
> can be determined from the CPU number.
> 
> v2: - Dropped first two patches which were merged into another patch in
>        the parallel boot series.
>      - Fixed a compile error in patch 1 found by the kernel test robot.
>      - Split out the removal of STARTUP_SECONDARY into a separate patch
>        and renumber the remaining flags.
> 
> Brian Gerst (5):
>    x86/smpboot: Remove initial_stack on 64-bit
>    x86/smpboot: Remove early_gdt_descr on 64-bit
>    x86/smpboot: Remove initial_gs
>    x86/smpboot: Simplify boot CPU setup
>    x86/smpboot: Remove STARTUP_SECONDARY
> 
>   arch/x86/include/asm/processor.h |  6 +-
>   arch/x86/include/asm/realmode.h  |  1 -
>   arch/x86/include/asm/smp.h       |  5 +-
>   arch/x86/kernel/acpi/sleep.c     |  5 +-
>   arch/x86/kernel/head_64.S        | 99 ++++++++++++--------------------
>   arch/x86/kernel/smpboot.c        |  6 +-
>   arch/x86/xen/xen-head.S          |  2 +-
>   7 files changed, 49 insertions(+), 75 deletions(-)
> 

Its weird putting something in earlier patches like 
STARTUP_APICID_CPUID_*,STARTUP_SECONDARY.. and removing/changing it 
later on in *the same series*. Maybe better to keep this as a separate 
series from parallel smp? i.e. not include this in v12 and review it 
separately? Happy with whatever you and David decide..

Thanks,
Usama