[PATCH v2] ARM: map ATAGs when not in first 1MB of RAM

Rob Herring robherring2 at gmail.com
Sat Jan 29 02:10:41 EST 2011


Russell,

On 01/28/2011 08:10 AM, Russell King - ARM Linux wrote:
> On Fri, Jan 28, 2011 at 08:00:46AM -0600, Rob Herring wrote:
>> @@ -206,11 +206,17 @@ __create_page_tables:
>>   #endif
>>
>>   	/*
>> -	 * Then map first 1MB of ram in case it contains our boot params.
>> +	 * Then map boot params address in r2 or
>> +	 * the first 1MB of ram if boot params address is not specified.
>>   	 */
>> -	add	r0, r4, #PAGE_OFFSET>>  18
>> -	orr	r6, r7, r8
>> -	str	r6, [r0]
>> +	mov	r0, r2, lsr #20
>> +	movs	r0, r0, lsl #20
>> +	moveq	r0, r8
>> +	sub	r3, r0, r8
>> +	add	r3, r3, #PAGE_OFFSET
>> +	add	r3, r4, r3, lsr #18
>> +	orr	r6, r7, r0
>> +	str	r6, [r3]
>
> Wouldn't:
> 	str	r6, [r4, r3, lsr #18]
> work here?

Not on Thumb2:

arch/arm/kernel/head.S:218: Error: Thumb supports only LSL in shifted 
register indexing -- `str r6,[r4,r3,lsr#18]'

Rob



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