Re: IP32 prom crashes due to __pa() funkiness

[Kumba <kumba@gentoo.org>]

Kumba wrote:
> peter fuerst wrote:
>>
>> Hi!
>>
>> Did you try to use PHYS_OFFSET > 0 ?  __pa() ist still (as of
>> d3fbd83ff545e49e2a0a5ca0f00dda4eedaf8be7) defined as (casts omitted):
>>
>> #define __pa(x) (x - (x < CKSEG0 ? PAGE_OFFSET:CKSEG0) + PHYS_OFFSET)
>>
>> This gives __pa(CKSEG0) == PHYS_OFFSET, which will never work for
>> PHYS_OFFSET > 0. A quick fix (assuming this was the cause for failure)
>> could be:
>>
>> ========================================================================
>> --- 
>> d3fbd83ff545e49e2a0a5ca0f00dda4eedaf8be7/include/asm-mips/page.h    
>> Sat Mar 10 08:43:17 2007
>> +++ quickfix/include/asm-mips/page.h    Sun Mar 18 10:24:34 2007
>> @@ -150,7 +150,7 @@ typedef struct { unsigned long pgprot; }
>>   * __pa()/__va() should be used only during mem init.
>>   */
>>  #if defined(CONFIG_64BIT) && !defined(CONFIG_BUILD_ELF64)
>> -#define __pa_page_offset(x)    ((unsigned long)(x) < CKSEG0 ? 
>> PAGE_OFFSET : CKSEG0)
>> +#define __pa_page_offset(x)    ((unsigned long)(x) < CKSEG0 ? 
>> PAGE_OFFSET : CKSEG0+PHYS_OFFSET)
>>  #else
>>  #define __pa_page_offset(x)    PAGE_OFFSET
>>  #endif
>>
>>
>> Signed-off-by: peter fuerst <post@pfrst.de>
>>
>> ========================================================================
>>
>> Of course, "#define PAGE_OFFSET (CAC_BASE + PHYS_OFFSET)" is also needed.
>>
>> kind regards
>>
>> peter
> 
> Hmm, I can't find where PHYS_OFFSET is defined for mips.  A grep shows 
> it mostly existing for the arm arch.  Is there an alternative macro 
> available, or is this something that needs porting over?
> 
> 
> --Kumba

Ah, duh.  PHYS_OFFSET was introduced post-2.6.20, so I won't be able to leverage 
this w/o backporting.


--Kumba

-- 
Gentoo/MIPS Team Lead

"Such is oft the course of deeds that move the wheels of the world: small hands 
do them because they must, while the eyes of the great are elsewhere."  --Elrond