[PATCH] PPC 85xx failure with odd memory sizes and CONFIG_HIGHMEM

Kumar Gala galak at kernel.crashing.org
Thu Oct 4 06:49:43 EST 2007

On Oct 3, 2007, at 2:34 PM, Rune Torgersen wrote:

>> From: Dale Farnsworth
>> The CONFIG_FSL_BOOKE mmu setup code fails when CONFIG_HIGHMEM=y
>> and the 3 fixed TLB entries cannot exactly map the lowmem size.
>> Each TLB entry can map 4MB, 16MB, 64MB or 256MB, so the failure
>> is observed when the kernel lowmem size is not equal to the
>> sum of up to 3 of those values.
> Does this mean you cannot run 1G of lowmem on a 85xx?
> On 82xx I run 1G of lowmem, and when we finaly upgrade our product  
> to a
> 85xx something, Iw was planning on doing the same.

The code would have to change to allow for 1G of lowmem.

Max lowmem with KERNELBASE @ 0xc000_0000 is 768M.

- k

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