powerpc/mm/hash: Properly mask the ESID bits when building proto-VSID

Michael Ellerman patch-notifications at ellerman.id.au
Wed Feb 1 12:05:32 AEDT 2017

On Sat, 2017-01-28 at 15:48:40 UTC, "Aneesh Kumar K.V" wrote:
> proto-vsid is built using both mmu context id and ESID. We should not have
> overlapping bits between those. That will result in us having vsid
> collision. With the current code we missed masking the top bits of effective
> address. This implies for kernel address we ended up using the top 4 bits
> as part of proto-vsid, which is wrong. For the kernel we should have the
> below mapping
> 0xf000000000000000 -> 0x7ffff  (19 bits context + 6 bits ESID ).
> Without the patch we endup with
> 0xf000000000000000 ->  0xf7ffff (0x7ffff | 0xf00000)
> We didn't observe any issues till now possibly because we never end up
> using a context value which could map to the same  VSID as kernel.
> Fixes: c60ac5693c4 ("powerpc: Update kernel VSID range")
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>

Applied to powerpc next, thanks.



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