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65 lines
1.8 KiB
65 lines
1.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* This file contains the routines for handling the MMU. |
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* |
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* Copyright (C) 2007 Xilinx, Inc. All rights reserved. |
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* |
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* Derived from arch/ppc/mm/4xx_mmu.c: |
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* -- paulus |
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* |
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* Derived from arch/ppc/mm/init.c: |
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* Copyright (C) 1995-1996 Gary Thomas ([email protected]) |
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* |
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* Modifications by Paul Mackerras (PowerMac) ([email protected]) |
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* and Cort Dougan (PReP) ([email protected]) |
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* Copyright (C) 1996 Paul Mackerras |
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* Amiga/APUS changes by Jesper Skov ([email protected]). |
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* |
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* Derived from "arch/i386/mm/init.c" |
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
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*/ |
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#include <linux/mm.h> |
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#include <linux/init.h> |
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#include <asm/tlbflush.h> |
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#include <asm/mmu_context.h> |
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mm_context_t next_mmu_context; |
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unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; |
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atomic_t nr_free_contexts; |
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struct mm_struct *context_mm[LAST_CONTEXT+1]; |
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/* |
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* Initialize the context management stuff. |
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*/ |
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void __init mmu_context_init(void) |
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{ |
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/* |
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* The use of context zero is reserved for the kernel. |
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* This code assumes FIRST_CONTEXT < 32. |
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*/ |
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context_map[0] = (1 << FIRST_CONTEXT) - 1; |
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next_mmu_context = FIRST_CONTEXT; |
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atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); |
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} |
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/* |
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* Steal a context from a task that has one at the moment. |
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* |
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* This isn't an LRU system, it just frees up each context in |
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* turn (sort-of pseudo-random replacement :). This would be the |
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* place to implement an LRU scheme if anyone were motivated to do it. |
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*/ |
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void steal_context(void) |
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{ |
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struct mm_struct *mm; |
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/* free up context `next_mmu_context' */ |
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/* if we shouldn't free context 0, don't... */ |
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if (next_mmu_context < FIRST_CONTEXT) |
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next_mmu_context = FIRST_CONTEXT; |
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mm = context_mm[next_mmu_context]; |
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flush_tlb_mm(mm); |
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destroy_context(mm); |
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}
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