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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 | // SPDX-License-Identifier: GPL-2.0 /* * linux/arch/cris/arch-v10/mm/tlb.c * * Low level TLB handling * * * Copyright (C) 2000-2007 Axis Communications AB * * Authors: Bjorn Wesen (bjornw@axis.com) * */ #include <linux/mm_types.h> #include <asm/tlb.h> #include <asm/mmu_context.h> #include <arch/svinto.h> #define D(x) /* The TLB can host up to 64 different mm contexts at the same time. * The running context is R_MMU_CONTEXT, and each TLB entry contains a * page_id that has to match to give a hit. In page_id_map, we keep track * of which mm's we have assigned which page_id's, so that we know when * to invalidate TLB entries. * * The last page_id is never running - it is used as an invalid page_id * so we can make TLB entries that will never match. * * Notice that we need to make the flushes atomic, otherwise an interrupt * handler that uses vmalloced memory might cause a TLB load in the middle * of a flush causing. */ /* invalidate all TLB entries */ void flush_tlb_all(void) { int i; unsigned long flags; /* the vpn of i & 0xf is so we dont write similar TLB entries * in the same 4-way entry group. details... */ local_irq_save(flags); for(i = 0; i < NUM_TLB_ENTRIES; i++) { *R_TLB_SELECT = ( IO_FIELD(R_TLB_SELECT, index, i) ); *R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) | IO_FIELD(R_TLB_HI, vpn, i & 0xf ) ); *R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) | IO_STATE(R_TLB_LO, valid, no ) | IO_STATE(R_TLB_LO, kernel,no ) | IO_STATE(R_TLB_LO, we, no ) | IO_FIELD(R_TLB_LO, pfn, 0 ) ); } local_irq_restore(flags); D(printk("tlb: flushed all\n")); } /* invalidate the selected mm context only */ void flush_tlb_mm(struct mm_struct *mm) { int i; int page_id = mm->context.page_id; unsigned long flags; D(printk("tlb: flush mm context %d (%p)\n", page_id, mm)); if(page_id == NO_CONTEXT) return; /* mark the TLB entries that match the page_id as invalid. * here we could also check the _PAGE_GLOBAL bit and NOT flush * global pages. is it worth the extra I/O ? */ local_irq_save(flags); for(i = 0; i < NUM_TLB_ENTRIES; i++) { *R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i); if (IO_EXTRACT(R_TLB_HI, page_id, *R_TLB_HI) == page_id) { *R_TLB_HI = ( IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) | IO_FIELD(R_TLB_HI, vpn, i & 0xf ) ); *R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) | IO_STATE(R_TLB_LO, valid, no ) | IO_STATE(R_TLB_LO, kernel,no ) | IO_STATE(R_TLB_LO, we, no ) | IO_FIELD(R_TLB_LO, pfn, 0 ) ); } } local_irq_restore(flags); } /* invalidate a single page */ void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) { struct mm_struct *mm = vma->vm_mm; int page_id = mm->context.page_id; int i; unsigned long flags; D(printk("tlb: flush page %p in context %d (%p)\n", addr, page_id, mm)); if(page_id == NO_CONTEXT) return; addr &= PAGE_MASK; /* perhaps not necessary */ /* invalidate those TLB entries that match both the mm context * and the virtual address requested */ local_irq_save(flags); for(i = 0; i < NUM_TLB_ENTRIES; i++) { unsigned long tlb_hi; *R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i); tlb_hi = *R_TLB_HI; if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id && (tlb_hi & PAGE_MASK) == addr) { *R_TLB_HI = IO_FIELD(R_TLB_HI, page_id, INVALID_PAGEID ) | addr; /* same addr as before works. */ *R_TLB_LO = ( IO_STATE(R_TLB_LO, global,no ) | IO_STATE(R_TLB_LO, valid, no ) | IO_STATE(R_TLB_LO, kernel,no ) | IO_STATE(R_TLB_LO, we, no ) | IO_FIELD(R_TLB_LO, pfn, 0 ) ); } } local_irq_restore(flags); } /* * Initialize the context related info for a new mm_struct * instance. */ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { mm->context.page_id = NO_CONTEXT; return 0; } /* called in schedule() just before actually doing the switch_to */ void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { if (prev != next) { /* make sure we have a context */ get_mmu_context(next); /* remember the pgd for the fault handlers * this is similar to the pgd register in some other CPU's. * we need our own copy of it because current and active_mm * might be invalid at points where we still need to derefer * the pgd. */ per_cpu(current_pgd, smp_processor_id()) = next->pgd; /* switch context in the MMU */ D(printk(KERN_DEBUG "switching mmu_context to %d (%p)\n", next->context, next)); *R_MMU_CONTEXT = IO_FIELD(R_MMU_CONTEXT, page_id, next->context.page_id); } } |