From 837cd0bdf54dd954cd6aa43d250f75ab5db79617 Mon Sep 17 00:00:00 2001 From: Robin Holt Date: Fri, 11 Nov 2005 09:35:43 -0600 Subject: [IA64] 4-level page tables This patch introduces 4-level page tables to ia64. I have run some benchmarks and found nothing interesting. Performance has consistently fallen within the noise range. It also introduces a config option (setting the default to 3 levels). The config option prevents having 4 level page tables with 64k base page size. Signed-off-by: Robin Holt Signed-off-by: Tony Luck --- arch/ia64/kernel/ivt.S | 63 ++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 48 insertions(+), 15 deletions(-) (limited to 'arch/ia64/kernel/ivt.S') diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S index c13ca0d49c4..e06f21f60dc 100644 --- a/arch/ia64/kernel/ivt.S +++ b/arch/ia64/kernel/ivt.S @@ -114,7 +114,7 @@ ENTRY(vhpt_miss) shl r21=r16,3 // shift bit 60 into sign bit shr.u r17=r16,61 // get the region number into r17 ;; - shr r22=r21,3 + shr.u r22=r21,3 #ifdef CONFIG_HUGETLB_PAGE extr.u r26=r25,2,6 ;; @@ -140,20 +140,34 @@ ENTRY(vhpt_miss) (p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=PTA + IFA(33,42)*8 (p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=PTA + (((IFA(61,63) << 7) | IFA(33,39))*8) cmp.eq p7,p6=0,r21 // unused address bits all zeroes? - shr.u r18=r22,PMD_SHIFT // shift L2 index into position +#ifdef CONFIG_PGTABLE_4 + shr.u r28=r22,PUD_SHIFT // shift L2 index into position +#else + shr.u r18=r22,PMD_SHIFT // shift L3 index into position +#endif ;; ld8 r17=[r17] // fetch the L1 entry (may be 0) ;; (p7) cmp.eq p6,p7=r17,r0 // was L1 entry NULL? - dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry +#ifdef CONFIG_PGTABLE_4 + dep r28=r28,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry + ;; + shr.u r18=r22,PMD_SHIFT // shift L3 index into position +(p7) ld8 r29=[r28] // fetch the L2 entry (may be 0) ;; -(p7) ld8 r20=[r17] // fetch the L2 entry (may be 0) - shr.u r19=r22,PAGE_SHIFT // shift L3 index into position +(p7) cmp.eq.or.andcm p6,p7=r29,r0 // was L2 entry NULL? + dep r17=r18,r29,3,(PAGE_SHIFT-3) // compute address of L3 page table entry +#else + dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L3 page table entry +#endif ;; -(p7) cmp.eq.or.andcm p6,p7=r20,r0 // was L2 entry NULL? - dep r21=r19,r20,3,(PAGE_SHIFT-3) // compute address of L3 page table entry +(p7) ld8 r20=[r17] // fetch the L3 entry (may be 0) + shr.u r19=r22,PAGE_SHIFT // shift L4 index into position ;; -(p7) ld8 r18=[r21] // read the L3 PTE +(p7) cmp.eq.or.andcm p6,p7=r20,r0 // was L3 entry NULL? + dep r21=r19,r20,3,(PAGE_SHIFT-3) // compute address of L4 page table entry + ;; +(p7) ld8 r18=[r21] // read the L4 PTE mov r19=cr.isr // cr.isr bit 0 tells us if this is an insn miss ;; (p7) tbit.z p6,p7=r18,_PAGE_P_BIT // page present bit cleared? @@ -192,14 +206,21 @@ ENTRY(vhpt_miss) * between reading the pagetable and the "itc". If so, flush the entry we * inserted and retry. */ - ld8 r25=[r21] // read L3 PTE again - ld8 r26=[r17] // read L2 entry again + ld8 r25=[r21] // read L4 entry again + ld8 r26=[r17] // read L3 PTE again +#ifdef CONFIG_PGTABLE_4 + ld8 r18=[r28] // read L2 entry again +#endif + cmp.ne p6,p7=r0,r0 ;; - cmp.ne p6,p7=r26,r20 // did L2 entry change + cmp.ne.or.andcm p6,p7=r26,r20 // did L3 entry change +#ifdef CONFIG_PGTABLE_4 + cmp.ne.or.andcm p6,p7=r29,r18 // did L4 PTE change +#endif mov r27=PAGE_SHIFT<<2 ;; (p6) ptc.l r22,r27 // purge PTE page translation -(p7) cmp.ne.or.andcm p6,p7=r25,r18 // did L3 PTE change +(p7) cmp.ne.or.andcm p6,p7=r25,r18 // did L4 PTE change ;; (p6) ptc.l r16,r27 // purge translation #endif @@ -432,18 +453,30 @@ ENTRY(nested_dtlb_miss) (p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=PTA + IFA(33,42)*8 (p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=PTA + (((IFA(61,63) << 7) | IFA(33,39))*8) cmp.eq p7,p6=0,r21 // unused address bits all zeroes? - shr.u r18=r22,PMD_SHIFT // shift L2 index into position +#ifdef CONFIG_PGTABLE_4 + shr.u r18=r22,PUD_SHIFT // shift L2 index into position +#else + shr.u r18=r22,PMD_SHIFT // shift L3 index into position +#endif ;; ld8 r17=[r17] // fetch the L1 entry (may be 0) ;; (p7) cmp.eq p6,p7=r17,r0 // was L1 entry NULL? dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry ;; +#ifdef CONFIG_PGTABLE_4 (p7) ld8 r17=[r17] // fetch the L2 entry (may be 0) - shr.u r19=r22,PAGE_SHIFT // shift L3 index into position + shr.u r18=r22,PMD_SHIFT // shift L3 index into position ;; (p7) cmp.eq.or.andcm p6,p7=r17,r0 // was L2 entry NULL? - dep r17=r19,r17,3,(PAGE_SHIFT-3) // compute address of L3 page table entry + dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry + ;; +#endif +(p7) ld8 r17=[r17] // fetch the L3 entry (may be 0) + shr.u r19=r22,PAGE_SHIFT // shift L4 index into position + ;; +(p7) cmp.eq.or.andcm p6,p7=r17,r0 // was L3 entry NULL? + dep r17=r19,r17,3,(PAGE_SHIFT-3) // compute address of L4 page table entry (p6) br.cond.spnt page_fault mov b0=r30 br.sptk.many b0 // return to continuation point -- cgit v1.2.3-18-g5258