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Diffstat (limited to 'arch/openrisc/mm/tlb.c')
| -rw-r--r-- | arch/openrisc/mm/tlb.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/arch/openrisc/mm/tlb.c b/arch/openrisc/mm/tlb.c new file mode 100644 index 00000000000..683bd4d31c7 --- /dev/null +++ b/arch/openrisc/mm/tlb.c @@ -0,0 +1,192 @@ +/* + * OpenRISC tlb.c + * + * Linux architectural port borrowing liberally from similar works of + * others. All original copyrights apply as per the original source + * declaration. + * + * Modifications for the OpenRISC architecture: + * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> + * Copyright (C) 2010-2011 Julius Baxter <julius.baxter@orsoc.se> + * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#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/segment.h> +#include <asm/tlbflush.h> +#include <asm/pgtable.h> +#include <asm/mmu_context.h> +#include <asm/spr_defs.h> + +#define NO_CONTEXT -1 + +#define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ + SPR_DMMUCFGR_NTS_OFF)) +#define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ + SPR_IMMUCFGR_NTS_OFF)) +#define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1)) +#define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1)) +/* + * Invalidate all TLB entries. + * + * This comes down to setting the 'valid' bit for all xTLBMR registers to 0. + * Easiest way to accomplish this is to just zero out the xTLBMR register + * completely. + * + */ + +void flush_tlb_all(void) +{ + int i; + unsigned long num_tlb_sets; + + /* Determine number of sets for IMMU. */ + /* FIXME: Assumption is I & D nsets equal. */ + num_tlb_sets = NUM_ITLB_SETS; + + for (i = 0; i < num_tlb_sets; i++) { + mtspr_off(SPR_DTLBMR_BASE(0), i, 0); + mtspr_off(SPR_ITLBMR_BASE(0), i, 0); + } +} + +#define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI) +#define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI) + +/* + * Invalidate a single page. This is what the xTLBEIR register is for. + * + * There's no point in checking the vma for PAGE_EXEC to determine whether it's + * the data or instruction TLB that should be flushed... that would take more + * than the few instructions that the following compiles down to! + * + * The case where we don't have the xTLBEIR register really only works for + * MMU's with a single way and is hard-coded that way. + */ + +#define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr) +#define flush_dtlb_page_no_eir(addr) \ + mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0); + +#define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr) +#define flush_itlb_page_no_eir(addr) \ + mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0); + +void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) +{ + if (have_dtlbeir) + flush_dtlb_page_eir(addr); + else + flush_dtlb_page_no_eir(addr); + + if (have_itlbeir) + flush_itlb_page_eir(addr); + else + flush_itlb_page_no_eir(addr); +} + +void flush_tlb_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + int addr; + bool dtlbeir; + bool itlbeir; + + dtlbeir = have_dtlbeir; + itlbeir = have_itlbeir; + + for (addr = start; addr < end; addr += PAGE_SIZE) { + if (dtlbeir) + flush_dtlb_page_eir(addr); + else + flush_dtlb_page_no_eir(addr); + + if (itlbeir) + flush_itlb_page_eir(addr); + else + flush_itlb_page_no_eir(addr); + } +} + +/* + * Invalidate the selected mm context only. + * + * FIXME: Due to some bug here, we're flushing everything for now. + * This should be changed to loop over over mm and call flush_tlb_range. + */ + +void flush_tlb_mm(struct mm_struct *mm) +{ + + /* Was seeing bugs with the mm struct passed to us. Scrapped most of + this function. */ + /* Several architctures do this */ + flush_tlb_all(); +} + +/* called in schedule() just before actually doing the switch_to */ + +void switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *next_tsk) +{ + /* 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. + */ + current_pgd = next->pgd; + + /* We don't have context support implemented, so flush all + * entries belonging to previous map + */ + + if (prev != next) + flush_tlb_mm(prev); + +} + +/* + * 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; +} + +/* 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. + */ + +void destroy_context(struct mm_struct *mm) +{ + flush_tlb_mm(mm); + +} + +/* called once during VM initialization, from init.c */ + +void __init tlb_init(void) +{ + /* Do nothing... */ + /* invalidate the entire TLB */ + /* flush_tlb_all(); */ +} |