On Sun, Feb 21, 2016 at 01:11:17PM +0530, Aneesh Kumar K.V wrote: > "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> writes: > > > Paul Mackerras <pau...@samba.org> writes: > > > >> This patch series modifies the Linux PTE format used on 64-bit Book3S > >> processors (i.e. POWER server processors) to make the bits line up > >> with the PTE format used in the radix trees defined in PowerISA v3.0. > >> This will reduce the amount of further change required to make a > >> kernel that can run with either a radix MMU or a hashed page table > >> (HPT) MMU. > >> > >> This also changes the upper levels of the tree to use real addresses > >> rather than kernel virtual addresses - that is, we no longer have the > >> 0xc000... at the top of each PGD/PUD/PMD entry. I made this change > >> for all 64-bit machines, both embedded and server. > >> > >> The patch series is against v4.5-rc4 plus Aneesh's "powerpc/mm/hash: > >> Clear the invalid slot information correctly" patch. > >> > >> I have compiled this for all the defconfigs in the tree, without > >> error. I have tested this, with the fixes branch of the powerpc tree > >> merged in, both running bare-metal on a POWER8 and in a KVM guest on > >> that POWER8 system. In the guest I tested both 4k and 64k configs, > >> with THP enabled; in the host I tested with 64k page size and THP > >> enabled. All these tests ran fine, including running a KVM guest on > >> the bare-metal system. So far I have done kernel compiles in a loop > >> as the test, but I plan to run LTP and possibly some other tests. > >> > >> Comments welcome. > > > > I was expecting some complex changes in asm and other part of the code. That > > is one of the reason I was holding of a series like this till I get the > > radix merged. I should have really tried the radix/hash linux page table > > consolidation to see the impact. > > One of the details that i hit last time with _PAGE_PTE was the usage of > @h symbol in asm code. I did a quick look and I guess we are ok. But it > will be good to double check. pmdp_splitting_flush (which got removed) > had usages like %4@h etc
I have done some pretty thorough grepping in arch/powerpc. There is no assembly code left that manipulates Linux PTEs (on 64-bit Book 3S, that is), because you converted it all to C code. :) There are a couple of bits of inline asm, but the only bit that is used as an immediate value is _PAGE_BUSY, which goes from 0x800 to 0x200, and could actually stay at 0x800 in fact. Paul. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
