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