Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Russell King | 4baa992 | 2008-08-02 10:55:55 +0100 | [diff] [blame] | 2 | * arch/arm/include/asm/mmu_context.h |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Copyright (C) 1996 Russell King. |
| 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 | * Changelog: |
| 11 | * 27-06-1996 RMK Created |
| 12 | */ |
| 13 | #ifndef __ASM_ARM_MMU_CONTEXT_H |
| 14 | #define __ASM_ARM_MMU_CONTEXT_H |
| 15 | |
Russell King | 8dc39b8 | 2005-11-16 17:23:57 +0000 | [diff] [blame] | 16 | #include <linux/compiler.h> |
Russell King | 87c5257 | 2008-11-29 17:35:51 +0000 | [diff] [blame] | 17 | #include <linux/sched.h> |
Russell King | 4fe15ba | 2005-11-06 19:47:04 +0000 | [diff] [blame] | 18 | #include <asm/cacheflush.h> |
Russell King | 46097c7 | 2008-08-10 18:10:19 +0100 | [diff] [blame] | 19 | #include <asm/cachetype.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <asm/proc-fns.h> |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 21 | #include <asm-generic/mm_hooks.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | |
Russell King | ff0daca | 2006-06-29 20:17:15 +0100 | [diff] [blame] | 23 | void __check_kvm_seq(struct mm_struct *mm); |
| 24 | |
Russell King | 516793c | 2007-05-17 10:19:23 +0100 | [diff] [blame] | 25 | #ifdef CONFIG_CPU_HAS_ASID |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | |
| 27 | /* |
| 28 | * On ARMv6, we have the following structure in the Context ID: |
| 29 | * |
| 30 | * 31 7 0 |
| 31 | * +-------------------------+-----------+ |
| 32 | * | process ID | ASID | |
| 33 | * +-------------------------+-----------+ |
| 34 | * | context ID | |
| 35 | * +-------------------------------------+ |
| 36 | * |
| 37 | * The ASID is used to tag entries in the CPU caches and TLBs. |
| 38 | * The context ID is used by debuggers and trace logic, and |
| 39 | * should be unique within all running processes. |
| 40 | */ |
Russell King | 8678c1f | 2007-05-08 20:03:09 +0100 | [diff] [blame] | 41 | #define ASID_BITS 8 |
| 42 | #define ASID_MASK ((~0) << ASID_BITS) |
| 43 | #define ASID_FIRST_VERSION (1 << ASID_BITS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | |
| 45 | extern unsigned int cpu_last_asid; |
Catalin Marinas | 11805bc | 2010-01-26 19:09:42 +0100 | [diff] [blame^] | 46 | #ifdef CONFIG_SMP |
| 47 | DECLARE_PER_CPU(struct mm_struct *, current_mm); |
| 48 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | |
| 50 | void __init_new_context(struct task_struct *tsk, struct mm_struct *mm); |
| 51 | void __new_context(struct mm_struct *mm); |
| 52 | |
| 53 | static inline void check_context(struct mm_struct *mm) |
| 54 | { |
Catalin Marinas | 11805bc | 2010-01-26 19:09:42 +0100 | [diff] [blame^] | 55 | /* |
| 56 | * This code is executed with interrupts enabled. Therefore, |
| 57 | * mm->context.id cannot be updated to the latest ASID version |
| 58 | * on a different CPU (and condition below not triggered) |
| 59 | * without first getting an IPI to reset the context. The |
| 60 | * alternative is to take a read_lock on mm->context.id_lock |
| 61 | * (after changing its type to rwlock_t). |
| 62 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) |
| 64 | __new_context(mm); |
Russell King | ff0daca | 2006-06-29 20:17:15 +0100 | [diff] [blame] | 65 | |
| 66 | if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) |
| 67 | __check_kvm_seq(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | } |
| 69 | |
| 70 | #define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0) |
| 71 | |
| 72 | #else |
| 73 | |
Russell King | ff0daca | 2006-06-29 20:17:15 +0100 | [diff] [blame] | 74 | static inline void check_context(struct mm_struct *mm) |
| 75 | { |
Catalin Marinas | 9a45f02 | 2009-07-24 12:34:56 +0100 | [diff] [blame] | 76 | #ifdef CONFIG_MMU |
Russell King | ff0daca | 2006-06-29 20:17:15 +0100 | [diff] [blame] | 77 | if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) |
| 78 | __check_kvm_seq(mm); |
Catalin Marinas | 9a45f02 | 2009-07-24 12:34:56 +0100 | [diff] [blame] | 79 | #endif |
Russell King | ff0daca | 2006-06-29 20:17:15 +0100 | [diff] [blame] | 80 | } |
| 81 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | #define init_new_context(tsk,mm) 0 |
| 83 | |
| 84 | #endif |
| 85 | |
| 86 | #define destroy_context(mm) do { } while(0) |
| 87 | |
| 88 | /* |
| 89 | * This is called when "tsk" is about to enter lazy TLB mode. |
| 90 | * |
| 91 | * mm: describes the currently active mm context |
| 92 | * tsk: task which is entering lazy tlb |
| 93 | * cpu: cpu number which is entering lazy tlb |
| 94 | * |
| 95 | * tsk->mm will be NULL |
| 96 | */ |
| 97 | static inline void |
| 98 | enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) |
| 99 | { |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * This is the actual mm switch as far as the scheduler |
| 104 | * is concerned. No registers are touched. We avoid |
| 105 | * calling the CPU specific function when the mm hasn't |
| 106 | * actually changed. |
| 107 | */ |
| 108 | static inline void |
| 109 | switch_mm(struct mm_struct *prev, struct mm_struct *next, |
| 110 | struct task_struct *tsk) |
| 111 | { |
Russell King | 002547b | 2006-06-20 20:46:52 +0100 | [diff] [blame] | 112 | #ifdef CONFIG_MMU |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | unsigned int cpu = smp_processor_id(); |
| 114 | |
Catalin Marinas | 826cbda | 2008-06-13 10:28:36 +0100 | [diff] [blame] | 115 | #ifdef CONFIG_SMP |
| 116 | /* check for possible thread migration */ |
Rusty Russell | 56f8ba8 | 2009-09-24 09:34:49 -0600 | [diff] [blame] | 117 | if (!cpumask_empty(mm_cpumask(next)) && |
| 118 | !cpumask_test_cpu(cpu, mm_cpumask(next))) |
Catalin Marinas | 826cbda | 2008-06-13 10:28:36 +0100 | [diff] [blame] | 119 | __flush_icache_all(); |
| 120 | #endif |
Rusty Russell | 56f8ba8 | 2009-09-24 09:34:49 -0600 | [diff] [blame] | 121 | if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) { |
Catalin Marinas | 11805bc | 2010-01-26 19:09:42 +0100 | [diff] [blame^] | 122 | #ifdef CONFIG_SMP |
| 123 | struct mm_struct **crt_mm = &per_cpu(current_mm, cpu); |
| 124 | *crt_mm = next; |
| 125 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | check_context(next); |
| 127 | cpu_switch_mm(next->pgd, next); |
Russell King | 7e5e6e9 | 2005-11-03 20:32:45 +0000 | [diff] [blame] | 128 | if (cache_is_vivt()) |
Rusty Russell | 56f8ba8 | 2009-09-24 09:34:49 -0600 | [diff] [blame] | 129 | cpumask_clear_cpu(cpu, mm_cpumask(prev)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | } |
Russell King | 002547b | 2006-06-20 20:46:52 +0100 | [diff] [blame] | 131 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | } |
| 133 | |
| 134 | #define deactivate_mm(tsk,mm) do { } while (0) |
| 135 | #define activate_mm(prev,next) switch_mm(prev, next, NULL) |
| 136 | |
| 137 | #endif |