Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Russell King | d84b471 | 2006-08-21 19:23:38 +0100 | [diff] [blame] | 2 | * linux/arch/arm/mm/context.c |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | #include <linux/init.h> |
| 11 | #include <linux/sched.h> |
| 12 | #include <linux/mm.h> |
| 13 | |
| 14 | #include <asm/mmu_context.h> |
| 15 | #include <asm/tlbflush.h> |
| 16 | |
| 17 | unsigned int cpu_last_asid = { 1 << ASID_BITS }; |
| 18 | |
| 19 | /* |
| 20 | * We fork()ed a process, and we need a new context for the child |
| 21 | * to run in. We reserve version 0 for initial tasks so we will |
Catalin Marinas | 9d99df4 | 2007-02-05 14:47:40 +0100 | [diff] [blame] | 22 | * always allocate an ASID. The ASID 0 is reserved for the TTBR |
| 23 | * register changing sequence. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | */ |
| 25 | void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) |
| 26 | { |
| 27 | mm->context.id = 0; |
| 28 | } |
| 29 | |
| 30 | void __new_context(struct mm_struct *mm) |
| 31 | { |
| 32 | unsigned int asid; |
| 33 | |
| 34 | asid = ++cpu_last_asid; |
| 35 | if (asid == 0) |
| 36 | asid = cpu_last_asid = 1 << ASID_BITS; |
| 37 | |
| 38 | /* |
| 39 | * If we've used up all our ASIDs, we need |
| 40 | * to start a new version and flush the TLB. |
| 41 | */ |
Catalin Marinas | 9d99df4 | 2007-02-05 14:47:40 +0100 | [diff] [blame] | 42 | if ((asid & ~ASID_MASK) == 0) { |
| 43 | asid = ++cpu_last_asid; |
| 44 | /* set the reserved ASID before flushing the TLB */ |
| 45 | asm("mcr p15, 0, %0, c13, c0, 1 @ set reserved context ID\n" |
| 46 | : |
| 47 | : "r" (0)); |
| 48 | isb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | flush_tlb_all(); |
Catalin Marinas | 9d99df4 | 2007-02-05 14:47:40 +0100 | [diff] [blame] | 50 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | |
| 52 | mm->context.id = asid; |
| 53 | } |