Re: Rootfs in eMMC: Kernel panic ...Attempted to kill init!

[Dirk Behme <dirk.behme@googlemail.com>]

Hi Catalin,

Catalin Marinas wrote:
> On Mon, 2009-06-22 at 17:46 +0100, Russell King - ARM Linux wrote:
>> On Mon, Jun 22, 2009 at 05:13:16PM +0100, Catalin Marinas wrote:
>>> In my case (ext2 over pata_platform), there is no flush_dcache_page()
>>> call after the page was written with data from the CompactFlash (neither
>>> the driver nor the VFS layer do this and we used hardware tracing to
>>> double-check). When the page is mapped into user space,
>>> update_mmu_cache() is called but the page hasn't been marked as dirty
>>> and no D-cache flushing occurs. Calling flush_dcache_page() in
>>> mpage_end_io_read() works around this issue.
>> As already covered, there's no chance of adding such a call to the
>> generic kernel.  It's the responsibility of the drivers to ensure that
>> data they read in hits the underlying page - in the same way that DMA
>> does.
> 
> The patch below appears to solve the problem with CompactFlash using
> pata_platform (I cc'ed linux-ide since the patch changes their code).
> The patch only handles the read case but similarly it may need to handle
> the write case if D-cache aliasing between user and kernel mappings
> exists.
> 
> For the USB mass storage, I haven't yet figured out the best place to
> call flush_dcache_page().

Any news regarding USB mass storage on ARM MPCore? Else this would 
mean that USB mass storage (USB stick, USB disk) formatted with 
ext2/3/4 wouldn't work with MPCore?

Many thanks and best regards

Dirk