RPAGE_RSV0..4 pte bits are currently used for hpte slot
tracking. We need these bits for memory-protection
keys. Luckily these four bits are relatively easier
to move among all the other candidate bits.
For 64K linux-ptes backed by 4k hptes, these bits
are used for tracking the validity of the slot value
stored in the second-part-of-the-pte. We device a new
mechanism for tracking the validity without using
those bits. The mechanism is explained in the patch.
For 64K linux-pte backed by 64K hptes, we simply move
the slot tracking bits to the second-part-of-the-pte.
The above mechanism is also used to free the bits for
hugetlb linux-ptes.
For 4k linux-pte, we have only 3 free bits available.
We swizzle around the bits and release RPAGE_RSV{2,3,4}
for memory protection keys.
Testing:
--------
has survived kernel compilation on multiple platforms
p8 powernv hash-mode, p9 powernv hash-mode, p7 powervm,
p8-powervm, p8-kvm-guest.
Has survived git-bisect on p8 power-nv with 64K page
and 4K page.
History:
-------
This patchset is a spin-off from the memkey patchset.
version v9:
(1) rearranged the patch order. First the helper
routines are defined followed by the
patches that make use of the helpers.
version v8:
(1) an additional patch added to free up
RSV{2,3,4} on 4K linux-pte.
version v7:
(1) GIX bit reset change moved to the second
patch -- noticed by Aneesh.
(2) Separated this patches from memkey patchset
(3) merged a bunch of patches, that used the
helper function, into one.
version v6:
(1) No changes related to pte.
version v5:
(1) No changes related to pte.
version v4:
(1) No changes related to pte.
version v3:
(1) split the patches into smaller consumable
patches.
(2) A bug fix while invalidating a hpte slot
in __hash_page_4K()
-- noticed by Aneesh
version v2:
(1) fixed a bug in 4k hpte backed 64k pte
where page invalidation was not
done correctly, and initialization
of second-part-of-the-pte was not
done correctly if the pte was not
yet Hashed with a hpte.
-- Reported by Aneesh.
version v1: Initial version
Ram Pai (7):
powerpc: introduce pte_set_hash_slot() helper
powerpc: introduce pte_get_hash_gslot() helper
powerpc: Free up four 64K PTE bits in 4K backed HPTE pages
powerpc: Free up four 64K PTE bits in 64K backed HPTE pages
powerpc: Swizzle around 4K PTE bits to free up bit 5 and bit 6
powerpc: use helper functions to get and set hash slots
powerpc: capture the PTE format changes in the dump pte report
arch/powerpc/include/asm/book3s/64/hash-4k.h | 21 ++++
arch/powerpc/include/asm/book3s/64/hash-64k.h | 61 ++++++++----
arch/powerpc/include/asm/book3s/64/hash.h | 8 +-
arch/powerpc/mm/dump_linuxpagetables.c | 3 +-
arch/powerpc/mm/hash64_4k.c | 14 +--
arch/powerpc/mm/hash64_64k.c | 131 +++++++++++++------------
arch/powerpc/mm/hash_utils_64.c | 35 +++++--
arch/powerpc/mm/hugetlbpage-hash64.c | 18 ++--
8 files changed, 171 insertions(+), 120 deletions(-)
