/* * linux/arch/arm/mm/context.c * * Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/sched.h> #include <linux/mm.h> #include <asm/mmu_context.h> #include <asm/tlbflush.h> static DEFINE_SPINLOCK(cpu_asid_lock); unsigned int cpu_last_asid = ASID_FIRST_VERSION; /* * We fork()ed a process, and we need a new context for the child * to run in. We reserve version 0 for initial tasks so we will * always allocate an ASID. The ASID 0 is reserved for the TTBR * register changing sequence. */ void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) { mm->context.id = 0; } void __new_context(struct mm_struct *mm) { unsigned int asid; spin_lock(&cpu_asid_lock); asid = ++cpu_last_asid; if (asid == 0) asid = cpu_last_asid = ASID_FIRST_VERSION; /* * If we've used up all our ASIDs, we need * to start a new version and flush the TLB. */ if (unlikely((asid & ~ASID_MASK) == 0)) { asid = ++cpu_last_asid; /* set the reserved ASID before flushing the TLB */ asm("mcr p15, 0, %0, c13, c0, 1 @ set reserved context ID\n" : : "r" (0)); isb(); flush_tlb_all(); if (icache_is_vivt_asid_tagged()) { asm("mcr p15, 0, %0, c7, c5, 0 @ invalidate I-cache\n" "mcr p15, 0, %0, c7, c5, 6 @ flush BTAC/BTB\n" : : "r" (0)); dsb(); } } spin_unlock(&cpu_asid_lock); mm->cpu_vm_mask = cpumask_of_cpu(smp_processor_id()); mm->context.id = asid; }