linux-kernel - Re: [PATCH 2/4] x86/boot: replace __PHYSICAL_START with LOAD_PHYSICAL

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Message-ID: <20240314005426.5c3vqgxpq7pxs4h5@master>
Date: Thu, 14 Mar 2024 00:54:26 +0000
From: Wei Yang <richard.weiyang@...il.com>
To: Nikolay Borisov <nik.borisov@...e.com>
Cc: Wei Yang <richard.weiyang@...il.com>, tglx@...utronix.de,
	mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] x86/boot: replace __PHYSICAL_START with
 LOAD_PHYSICAL_ADDR

On Wed, Mar 13, 2024 at 12:29:37PM +0200, Nikolay Borisov wrote:
>
>
>On 13.03.24 г. 9:58 ч., Wei Yang wrote:
>> Both __PHYSICAL_START and LOAD_PHYSICAL_ADDR are defined to get aligned
>> CONFIG_PHYSICAL_START, so we can replace __PHYSICAL_START with
>> LOAD_PHYSICAL_ADDR. And then remove the definition of __PHYSICAL_START,
>> which is only used to define __START_KERNEL.
>> 
>> Since <asm/boot.h> includes <asm/pgtable_types.h>, which includes
>> <asm/page_types.h>, it is fine to move definition from <asm/boot.h> to
>> <asm/page_types.h>.
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@...il.com>
>> ---
>>   arch/x86/include/asm/boot.h       | 5 -----
>>   arch/x86/include/asm/page_types.h | 8 +++++---
>>   2 files changed, 5 insertions(+), 8 deletions(-)
>> 
>> diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h
>> index a38cc0afc90a..12cbc57d0128 100644
>> --- a/arch/x86/include/asm/boot.h
>> +++ b/arch/x86/include/asm/boot.h
>> @@ -6,11 +6,6 @@
>>   #include <asm/pgtable_types.h>
>>   #include <uapi/asm/boot.h>
>> -/* Physical address where kernel should be loaded. */
>> -#define LOAD_PHYSICAL_ADDR ((CONFIG_PHYSICAL_START \
>> -				+ (CONFIG_PHYSICAL_ALIGN - 1)) \
>> -				& ~(CONFIG_PHYSICAL_ALIGN - 1))
>> -
>>   /* Minimum kernel alignment, as a power of two */
>>   #ifdef CONFIG_X86_64
>>   # define MIN_KERNEL_ALIGN_LG2	PMD_SHIFT
>> diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
>> index 86bd4311daf8..acc1620fd121 100644
>> --- a/arch/x86/include/asm/page_types.h
>> +++ b/arch/x86/include/asm/page_types.h
>> @@ -31,10 +31,12 @@
>>   #define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_TSK_EXEC
>> -#define __PHYSICAL_START	ALIGN(CONFIG_PHYSICAL_START, \
>> -				      CONFIG_PHYSICAL_ALIGN)
>> +/* Physical address where kernel should be loaded. */
>> +#define LOAD_PHYSICAL_ADDR ((CONFIG_PHYSICAL_START \
>> +				+ (CONFIG_PHYSICAL_ALIGN - 1)) \
>> +				& ~(CONFIG_PHYSICAL_ALIGN - 1))
>
>Why don't you simply define LOAD_PHYSICAL_ADDR via
>ALIGN(CONFIG_PHYSICAL_START, CONFIG_PHYSICAL_ALING) it's way more readable.
>

Sure, will do it.

>> -#define __START_KERNEL		(__START_KERNEL_map + __PHYSICAL_START)
>> +#define __START_KERNEL		(__START_KERNEL_map + LOAD_PHYSICAL_ADDR)
>>   #ifdef CONFIG_X86_64
>>   #include <asm/page_64_types.h>

-- 
Wei Yang
Help you, Help me