Subject: Re: [PATCH v9] ACPI / init: Invoke early ACPI initialization earlier
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        "Zheng, Lv" <lv.zheng@intel.com>
References: <1505293975-26005-1-git-send-email-douly.fnst@cn.fujitsu.com>
 <1505294274-441-1-git-send-email-douly.fnst@cn.fujitsu.com>
CC: <linux-kernel@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, <x86@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Will Deacon <will.deacon@arm.com>,
        <linux-arm-kernel@lists.infradead.org>,
        Tony Luck <tony.luck@intel.com>, Fenghua Yu <fenghua.yu@intel.com>,
        <linux-ia64@vger.kernel.org>, <yinghai@kernel.org>, <bhe@redhat.com>,
        <bp@alien8.de>, <fengguang.wu@intel.com>
From: Dou Liyang <douly.fnst@cn.fujitsu.com>
Message-ID: <e4eadcbc-fe58-2d2c-818d-34e2f545db16@cn.fujitsu.com>
Date: Wed, 27 Sep 2017 09:41:49 +0800
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Hi Rafael, Zheng,

Welcome any comments!

Now, our patches are in tip tree, they are based on this
independent patch, we hope it can be merged earlier than our
patches to avoid ACPI Error. we need your advice and confirmation.

Thanks,
	dou.

At 09/13/2017 05:17 PM, Dou Liyang wrote:
> Linux uses acpi_early_init() to put the ACPI table management into the
> late stage from the early stage. This two stages are different. the
> mapped ACPI tables in early stage is temporary and should be unmapped,
> but in late stage, it is permanent and don't need to be unmapped.
>
> Originally, mapping and parsing the DMAR table should be in the late stage.
> However, Initializing interrupt delivery mode earlier will move it into
> the early stage. This causes an ACPI error warning when Linux reallocates
> the ACPI root tables.
>
> Commit b064a8fa77df ("ACPI / init: Switch over platform to the ACPI mode
> later") splits the ACPI early initialization code into acpi_early_init()
> and acpi_subsystem_init(). This makes acpi_early_init() more independently
>
> So, invoke acpi_early_init() earlier before late_time_init(), Keep the DMAR
> be mapped and parsed in late stage like before.
>
> Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> Cc: linux-acpi@vger.kernel.org
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> Cc: Zheng, Lv <lv.zheng@intel.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: x86@kernel.org
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: linux-ia64@vger.kernel.org
> Cc: yinghai@kernel.org
> Cc: bhe@redhat.com
> Cc: bp@alien8.de
> ---
>  init/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/init/main.c b/init/main.c
> index 0ee9c686..2fb98a4 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -664,12 +664,12 @@ asmlinkage __visible void __init start_kernel(void)
>  	debug_objects_mem_init();
>  	setup_per_cpu_pageset();
>  	numa_policy_init();
> +	acpi_early_init();
>  	if (late_time_init)
>  		late_time_init();
>  	calibrate_delay();
>  	pidmap_init();
>  	anon_vma_init();
> -	acpi_early_init();
>  #ifdef CONFIG_X86
>  	if (efi_enabled(EFI_RUNTIME_SERVICES))
>  		efi_enter_virtual_mode();
>