linux-kernel - Re: [PATCH 2/2] x86: reimplement mem boot option

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Message-ID: <5004F67D.7000809@cn.fujitsu.com>
Date:	Tue, 17 Jul 2012 13:22:05 +0800
From:	Wen Congyang <wency@...fujitsu.com>
To:	rob@...dley.net, tglx@...utronix.de,
	Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	bhelgaas@...gle.com, "H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/2] x86: reimplement mem boot option

At 06/28/2012 09:29 AM, Wen Congyang Wrote:
> Pin......

Ping again........

> 
> At 06/14/2012 04:12 PM, Wen Congyang Wrote:
>> Current mem boot option only can work for non efi environment. If the user
>> specifies add_efi_memmap, it cannot work for efi environment. In
>> the efi environment, we call e820_add_region() to add the memory map. So
>> we can modify __e820_add_region() and the mem boot option can work for
>> efi environment.
>>
>> Signed-off-by: Wen Congyang <wency@...fujitsu.com>
>> ---
>>  arch/x86/kernel/e820.c |   29 +++++++++++++++++++++++++----
>>  1 files changed, 25 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
>> index 4185797..20bc467 100644
>> --- a/arch/x86/kernel/e820.c
>> +++ b/arch/x86/kernel/e820.c
>> @@ -47,6 +47,7 @@ unsigned long pci_mem_start = 0xaeedbabe;
>>  #ifdef CONFIG_PCI
>>  EXPORT_SYMBOL(pci_mem_start);
>>  #endif
>> +static u64 mem_limit = ~0ULL;
>>  
>>  /*
>>   * This function checks if any part of the range <start,end> is mapped
>> @@ -119,6 +120,20 @@ static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
>>  		return;
>>  	}
>>  
>> +	if (start >= mem_limit) {
>> +		printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
>> +		       (unsigned long long)start,
>> +		       (unsigned long long)(start + size - 1));
>> +		return;
>> +	}
>> +
>> +	if (mem_limit - start < size) {
>> +		printk(KERN_ERR "e820: ingoring [mem %#010llx-%#010llx]\n",
>> +		       (unsigned long long)mem_limit,
>> +		       (unsigned long long)(start + size - 1));
>> +		size = mem_limit - start;
>> +	}
>> +
>>  	e820x->map[x].addr = start;
>>  	e820x->map[x].size = size;
>>  	e820x->map[x].type = type;
>> @@ -809,7 +824,7 @@ static int userdef __initdata;
>>  /* "mem=nopentium" disables the 4MB page tables. */
>>  static int __init parse_memopt(char *p)
>>  {
>> -	u64 mem_size;
>> +	char *oldp;
>>  
>>  	if (!p)
>>  		return -EINVAL;
>> @@ -825,11 +840,11 @@ static int __init parse_memopt(char *p)
>>  	}
>>  
>>  	userdef = 1;
>> -	mem_size = memparse(p, &p);
>> +	oldp = p;
>> +	mem_limit = memparse(p, &p);
>>  	/* don't remove all of memory when handling "mem={invalid}" param */
>> -	if (mem_size == 0)
>> +	if (mem_limit == 0 || p == oldp)
>>  		return -EINVAL;
>> -	e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
>>  
>>  	return 0;
>>  }
>> @@ -881,6 +896,12 @@ early_param("memmap", parse_memmap_opt);
>>  
>>  void __init finish_e820_parsing(void)
>>  {
>> +	if (mem_limit != ~0ULL) {
>> +		userdef = 1;
>> +		e820_remove_range(mem_limit, ULLONG_MAX - mem_limit,
>> +				  E820_RAM, 1);
>> +	}
>> +
>>  	if (userdef) {
>>  		u32 nr = e820.nr_map;
>>  
> 
> --
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