Re: More info for DSM w/r/t sunffb on 2.6.15-rc6

[Hugh Dickins]

On Fri, 23 Dec 2005, David S. Miller wrote:
> 
> So I think something as simple as returning -EINVAL in the SBUS
> framebuffer mmap() driver if VM_SHARED is not set would be sufficient
> to deal with this.

That certainly gets my vote: it should work around the bug correctly
and effectively without adding any complexity.

Though really the check ought to be in the sparc and sparc64
io_remap_pfn_range, which are the guilty parties giving shared write
access even when none has been asked for.  But I guess it's too risky
to add failures or change behaviour down there at this stage.

Those "prot = __pgprot(pg_iobits);" lines - any idea why they ever
got inserted?  I guess to add _PAGE_E in the sparc64 case, and
whatever the equivalent was in the earlier sparc cases?
Can they safely be corrected early in 2.6.16?

Hugh
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