On Mon, Jul 09, 2012 at 06:43:41PM +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> > > Increase max addressable range to 64TB. This is not tested on > real hardware yet. > > Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/mmu-hash64.h | 8 ++++---- > arch/powerpc/include/asm/pgtable-ppc64-4k.h | 2 +- > arch/powerpc/include/asm/pgtable-ppc64-64k.h | 2 +- > arch/powerpc/include/asm/processor.h | 4 ++-- > arch/powerpc/include/asm/sparsemem.h | 4 ++-- > 5 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/include/asm/mmu-hash64.h > b/arch/powerpc/include/asm/mmu-hash64.h > index aa0d560..a227ba7 100644 > --- a/arch/powerpc/include/asm/mmu-hash64.h > +++ b/arch/powerpc/include/asm/mmu-hash64.h > @@ -374,16 +374,16 @@ extern void slb_set_size(u16 size); > */ > > #define VSID_MULTIPLIER_256M ASM_CONST(200730139) /* 28-bit prime */ > -#define VSID_BITS_256M 36 > +#define VSID_BITS_256M 38 > #define VSID_MODULUS_256M ((1UL<<VSID_BITS_256M)-1)
With these settings, the multiplication in ASM_VSID_SCRAMBLE could overflow, leading to incorrect results (which would cause occasional corruption of user processes under heavy load). You will need to reduce the multiplier to be less than 2^26, and it will need to be co-prime with 2^38 - 1. (Probably, the same value as we use in the 1T case would be OK.) Paul. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev