linux-kernel - Re: [PATCH 09/19] ARM64 / ACPI: Move the initialization of cpu_logical_map(0) before acpi_boot

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Date:	Fri, 25 Jul 2014 18:39:08 +0800
From:	Hanjun Guo <hanjun.guo@...aro.org>
To:	Mark Rutland <mark.rutland@....com>
CC:	Catalin Marinas <Catalin.Marinas@....com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"graeme.gregory@...aro.org" <graeme.gregory@...aro.org>,
	Arnd Bergmann <arnd@...db.de>,
	"grant.likely@...aro.org" <grant.likely@...aro.org>,
	Sudeep Holla <Sudeep.Holla@....com>,
	Will Deacon <Will.Deacon@....com>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <Marc.Zyngier@....com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Mark Brown <broonie@...aro.org>,
	Robert Richter <rric@...nel.org>,
	Lv Zheng <lv.zheng@...el.com>,
	Robert Moore <robert.moore@...el.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Liviu Dudau <Liviu.Dudau@....com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Charles Garcia-Tobin <Charles.Garcia-Tobin@....com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 09/19] ARM64 / ACPI: Move the initialization of cpu_logical_map(0)
 before acpi_boot_init()

On 2014-7-24 23:21, Mark Rutland wrote:
> On Thu, Jul 24, 2014 at 02:00:15PM +0100, Hanjun Guo wrote:
>> Move the initialization of cpu_logical_map(0) before acpi_boot_init()
>> to remove the duplicated initialization of cpu_logical_map(0).
> 
> It always make sense to initialise CPU0's logical map entry from the
> hardware values, so you could do this earlier in the series, before you
> introduce any ACPI code. Then you don't have the churn in acpi.c

ok, I will prepare a separate patch to do this before ACPI code, does it
make sense to you?

> 
>>
>> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
>> ---
>>  arch/arm64/kernel/acpi.c  |    3 ---
>>  arch/arm64/kernel/setup.c |    3 ++-
>>  2 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>> index 801e268..ff0f6a0 100644
>> --- a/arch/arm64/kernel/acpi.c
>> +++ b/arch/arm64/kernel/acpi.c
>> @@ -244,9 +244,6 @@ int __init acpi_boot_init(void)
>>  	if (err)
>>  		pr_err("Can't find FADT\n");
>>  
>> -	/* Get the boot CPU's MPIDR before MADT parsing */
>> -	cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
>> -
>>  	err = acpi_parse_madt_gic_cpu_interface_entries();
>>  
>>  	return err;
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index e00d40c..17ab98e 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -394,13 +394,14 @@ void __init setup_arch(char **cmdline_p)
>>  
>>  	efi_idmap_init();
>>  
>> +	/* Get the boot CPU's MPIDR before cpu logical map is built */
> 
> That comment's a bit useless; I think it can just be dropped.
> 
> All you need to do is move the initialisation of cpu_logical_map(0)
> before unflatten_device_tree(). When you introduce acpi_boot_init(),
> place it after the initialisation.

ok, I agree with you, will update it.

Thanks
Hanjun

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