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 | |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 17 | static DEFINE_SPINLOCK(cpu_asid_lock); |
| 18 | unsigned int cpu_last_asid = ASID_FIRST_VERSION; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
| 20 | /* |
| 21 | * We fork()ed a process, and we need a new context for the child |
| 22 | * 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] | 23 | * always allocate an ASID. The ASID 0 is reserved for the TTBR |
| 24 | * register changing sequence. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | */ |
| 26 | void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) |
| 27 | { |
| 28 | mm->context.id = 0; |
| 29 | } |
| 30 | |
| 31 | void __new_context(struct mm_struct *mm) |
| 32 | { |
| 33 | unsigned int asid; |
| 34 | |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 35 | spin_lock(&cpu_asid_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | asid = ++cpu_last_asid; |
| 37 | if (asid == 0) |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 38 | asid = cpu_last_asid = ASID_FIRST_VERSION; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | |
| 40 | /* |
| 41 | * If we've used up all our ASIDs, we need |
| 42 | * to start a new version and flush the TLB. |
| 43 | */ |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 44 | if (unlikely((asid & ~ASID_MASK) == 0)) { |
Catalin Marinas | 9d99df4 | 2007-02-05 14:47:40 +0100 | [diff] [blame] | 45 | asid = ++cpu_last_asid; |
| 46 | /* set the reserved ASID before flushing the TLB */ |
| 47 | asm("mcr p15, 0, %0, c13, c0, 1 @ set reserved context ID\n" |
| 48 | : |
| 49 | : "r" (0)); |
| 50 | isb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | flush_tlb_all(); |
Catalin Marinas | 065cf51 | 2007-05-09 09:50:23 +0100 | [diff] [blame] | 52 | if (icache_is_vivt_asid_tagged()) { |
| 53 | asm("mcr p15, 0, %0, c7, c5, 0 @ invalidate I-cache\n" |
| 54 | "mcr p15, 0, %0, c7, c5, 6 @ flush BTAC/BTB\n" |
| 55 | : |
| 56 | : "r" (0)); |
| 57 | dsb(); |
| 58 | } |
Catalin Marinas | 9d99df4 | 2007-02-05 14:47:40 +0100 | [diff] [blame] | 59 | } |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 60 | spin_unlock(&cpu_asid_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 62 | mm->cpu_vm_mask = cpumask_of_cpu(smp_processor_id()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | mm->context.id = asid; |
| 64 | } |