From: Stephen Williams <steve@icarus•com>
To: linuxppc-embedded@ozlabs•org
Subject: Re: Bigphysarea vs. kernel 2.4.32 and PPC405GPr
Date: Wed, 17 May 2006 10:07:57 -0700 [thread overview]
Message-ID: <e4fl9d$rka$1@sea.gmane.org> (raw)
In-Reply-To: <200605150835.48745.jgeissel@gmx.net>
That works nicely, thanks. I was under the mistaken impression that
the bigphysarea routines returned a physical address.
So now I can report that the bigphysarea patch works great on PPC
kernels 2.4.32+
Arno Geissel wrote:
> Try
>
> rc = remap_page_range(vma->vm_start,
> virt_to_phys(heap_map_base),
> npages*PAGE_SIZE,
> vma->vm_page_prot);
>
> Arno
>
>> I'm trying to use the bigphysarea patch to help me allocate big
>> physical chunks of memory for use by some custom embedded devices.
>> I've applied the bigphysarea-2.4.20 patch and built, no trouble,
>> and I've got it to config for my PPC. I can see at boot time that
>> the bigphysarea is getting its pages.
>>
>> I'm trying to use a mmap call to the driver to map a chunk of this
>> memory into the process. The mmap for the driver has this:
>>
>> pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
>> vma->vm_flags |= VM_RESERVED;
>>
>> npages = (vma->vm_end - vma->vm_start) / PAGE_SIZE;
>> heap_map_base = bigphysarea_alloc_pages(npages, 1, GFP_KERNEL);
>>
>> printk("XXXX Map base=%p, %ld pages\n", heap_map_base, npages);
>>
>> rc = remap_page_range(vma->vm_start,
>> (unsigned long)heap_map_base,
>> npages*PAGE_SIZE,
>> vma->vm_page_prot);
>>
>> The mmap returns without an error, but any access to the mapped
>> region gets me an immediate "Oops: machine check, sig: 7". I don't
>> see it. Where is the stupid mistake that I'm invariably making?
--
Steve Williams "The woods are lovely, dark and deep.
steve at icarus.com But I have promises to keep,
http://www.icarus.com and lines to code before I sleep,
http://www.picturel.com And lines to code before I sleep."
prev parent reply other threads:[~2006-05-17 17:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-12 23:31 Bigphysarea vs. kernel 2.4.32 and PPC405GPr Stephen Williams
2006-05-15 6:35 ` Arno Geissel
2006-05-17 17:07 ` Stephen Williams [this message]
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