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 first 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.
History:
-------
This patchset is a spin-off from the memkey patchset.
version v10:
(1) hidx value is rotated by one to save
initialization of the secondary-PTE.
(2) comments are not anymore right justified.
-- comment by mpe
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 (8):
powerpc: introduce pte_set_hidx() 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: shifted-by-one hidx value
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 | 20 ++++
arch/powerpc/include/asm/book3s/64/hash-64k.h | 71 ++++++++++----
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 | 123 +++++++++++++------------
arch/powerpc/mm/hash_utils_64.c | 35 +++++--
arch/powerpc/mm/hugetlbpage-hash64.c | 16 +--
8 files changed, 175 insertions(+), 115 deletions(-)
