Paul Mackerras <pau...@samba.org> writes: > On Mon, Jul 23, 2012 at 01:51:49PM +0530, Aneesh Kumar K.V wrote: >> Paul Mackerras <pau...@samba.org> writes: >> >> > On Mon, Jul 09, 2012 at 06:43:39PM +0530, Aneesh Kumar K.V wrote: >> >> From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> >> >> >> >> Increase the number of valid VSID bits in slbmte instruction. >> >> We will use the new bits when we increase valid VSID bits. >> >> >> >> Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> >> >> --- >> >> arch/powerpc/mm/slb_low.S | 4 ++-- >> >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> >> >> diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S >> >> index c355af6..c1fc81c 100644 >> >> --- a/arch/powerpc/mm/slb_low.S >> >> +++ b/arch/powerpc/mm/slb_low.S >> >> @@ -226,7 +226,7 @@ _GLOBAL(slb_allocate_user) >> >> */ >> >> slb_finish_load: >> >> ASM_VSID_SCRAMBLE(r10,r9,256M) >> >> - rldimi r11,r10,SLB_VSID_SHIFT,16 /* combine VSID and flags */ >> >> + rldimi r11,r10,SLB_VSID_SHIFT,2 /* combine VSID and flags */ >> > >> > You can't do that without either changing ASM_VSID_SCRAMBLE or masking >> > the VSID it generates to 36 bits, since the logic in ASM_VSID_SCRAMBLE >> > can leave non-zero bits in the high 28 bits of the result. Similarly >> > for the 1T case. >> > >> >> How about change ASM_VSID_SCRAMBLE to clear the high bits ? That would >> also make it close to vsid_scramble() > > One more instruction in a hot path - I'd rather not. How about > changing the rldimi instruction to: > rldimi r11,r10,SLB_VSID_SHIFT,(64-SLB_VSID_SHIFT-VSID_BITS_256M) > > and similarly for the 1T case. That will give the proper masking > when you change VSID_BITS_256M. >
This is better. I have made this change. -aneesh _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
