diff options
author | Ralf Baechle <ralf@linux-mips.org> | 2001-03-09 20:33:35 +0000 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2001-03-09 20:33:35 +0000 |
commit | 116674acc97ba75a720329996877077d988443a2 (patch) | |
tree | 6a3f2ff0b612ae2ee8a3f3509370c9e6333a53b3 /arch/cris/mm/tlb.c | |
parent | 71118c319fcae4a138f16e35b4f7e0a6d53ce2ca (diff) |
Merge with Linux 2.4.2.
Diffstat (limited to 'arch/cris/mm/tlb.c')
-rw-r--r-- | arch/cris/mm/tlb.c | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/arch/cris/mm/tlb.c b/arch/cris/mm/tlb.c new file mode 100644 index 000000000..ed74305ae --- /dev/null +++ b/arch/cris/mm/tlb.c @@ -0,0 +1,301 @@ +/* + * linux/arch/cris/mm/tlb.c + * + * Copyright (C) 2000 Axis Communications AB + * + * Authors: Bjorn Wesen (bjornw@axis.com) + * + */ + +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/mman.h> +#include <linux/mm.h> +#include <linux/init.h> + +#include <asm/system.h> +#include <asm/segment.h> +#include <asm/pgtable.h> +#include <asm/svinto.h> + +#define D(x) + +/* CRIS in Etrax100LX TLB */ + +#define NUM_TLB_ENTRIES 64 +#define NUM_PAGEID 64 +#define INVALID_PAGEID 63 +#define NO_CONTEXT -1 + +/* 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. + */ + +struct mm_struct *page_id_map[NUM_PAGEID]; + +static int map_replace_ptr = 1; /* which page_id_map entry to replace next */ + +/* invalidate all TLB entries */ + +void +flush_tlb_all() +{ + int i; + + /* the vpn of i & 0xf is so we dont write similar TLB entries + * in the same 4-way entry group. details.. + */ + + 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 ) ); + } + 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; + + 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 ? + */ + + 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 ) ); + } + } +} + +/* 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; + int i; + + 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 + */ + + 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 ) ); + } + } +} + +/* invalidate a page range */ + +void +flush_tlb_range(struct mm_struct *mm, + unsigned long start, + unsigned long end) +{ + int page_id = mm->context; + int i; + + D(printk("tlb: flush range %p<->%p in context %d (%p)\n", + start, end, page_id, mm)); + + if(page_id == NO_CONTEXT) + return; + + start &= PAGE_MASK; /* probably not necessary */ + end &= PAGE_MASK; /* dito */ + + /* invalidate those TLB entries that match both the mm context + * and the virtual address range + */ + + for(i = 0; i < NUM_TLB_ENTRIES; i++) { + unsigned long tlb_hi, vpn; + *R_TLB_SELECT = IO_FIELD(R_TLB_SELECT, index, i); + tlb_hi = *R_TLB_HI; + vpn = tlb_hi & PAGE_MASK; + if (IO_EXTRACT(R_TLB_HI, page_id, tlb_hi) == page_id && + vpn >= start && vpn < end) { + *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 ) ); + } + } +} + +/* + * 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 = NO_CONTEXT; + return 0; +} + +/* the following functions are similar to those used in the PPC port */ + +static inline void +alloc_context(struct mm_struct *mm) +{ + struct mm_struct *old_mm; + + D(printk("tlb: alloc context %d (%p)\n", map_replace_ptr, mm)); + + /* did we replace an mm ? */ + + old_mm = page_id_map[map_replace_ptr]; + + if(old_mm) { + /* throw out any TLB entries belonging to the mm we replace + * in the map + */ + flush_tlb_mm(old_mm); + + old_mm->context = NO_CONTEXT; + } + + /* insert it into the page_id_map */ + + mm->context = map_replace_ptr; + page_id_map[map_replace_ptr] = mm; + + map_replace_ptr++; + + if(map_replace_ptr == INVALID_PAGEID) + map_replace_ptr = 0; /* wrap around */ + +} + +/* + * if needed, get a new MMU context for the mm. otherwise nothing is done. + */ + +void +get_mmu_context(struct mm_struct *mm) +{ + if(mm->context == NO_CONTEXT) + alloc_context(mm); +} + +/* 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, int cpu) +{ + /* make sure we have a context */ + + get_mmu_context(next); + + /* switch context in the MMU */ + + D(printk("switching mmu_context to %d (%p)\n", next->context, next)); + + *R_MMU_CONTEXT = IO_FIELD(R_MMU_CONTEXT, page_id, next->context); +} + + +/* called by __exit_mm to destroy the used MMU context if any before + * destroying the mm itself. this is only called when the last user of the mm + * drops it. + * + * the only thing we really need to do here is mark the used PID slot + * as empty. + */ + +void +destroy_context(struct mm_struct *mm) +{ + if(mm->context != NO_CONTEXT) { + D(printk("destroy_context %d (%p)\n", mm->context, mm)); + flush_tlb_mm(mm); /* TODO this might be redundant ? */ + page_id_map[mm->context] = NULL; + /* mm->context = NO_CONTEXT; redundant.. mm will be freed */ + } +} + +/* called once during VM initialization, from init.c */ + +void __init +tlb_init(void) +{ + int i; + + /* clear the page_id map */ + + for(i = 0; i < 64; i++) + page_id_map[i] = NULL; + + /* invalidate the entire TLB */ + + flush_tlb_all(); + + /* the init_mm has context 0 from the boot */ + + page_id_map[0] = &init_mm; +} |