arch/blackfin/include/asm/mmu_context.h

   1 /*
   2  * File:         include/asm-blackfin/mmu_context.h
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #ifndef __BLACKFIN_MMU_CONTEXT_H__
  31 #define __BLACKFIN_MMU_CONTEXT_H__
  32
  33 #include <linux/gfp.h>
  34 #include <linux/sched.h>
  35 #include <asm/setup.h>
  36 #include <asm/page.h>
  37 #include <asm/pgalloc.h>
  38 #include <asm/cplbinit.h>
  39
  40 extern void *current_l1_stack_save;
  41 extern int nr_l1stack_tasks;
  42 extern void *l1_stack_base;
  43 extern unsigned long l1_stack_len;
  44
  45 extern int l1sram_free(const void*);
  46 extern void *l1sram_alloc_max(void*);
  47
  48 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  49 {
  50 }
  51
  52 /* Called when creating a new context during fork() or execve().  */
  53 static inline int
  54 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
  55 {
  56 #ifdef CONFIG_MPU
  57         unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
  58         mm->context.page_rwx_mask = (unsigned long *)p;
  59         memset(mm->context.page_rwx_mask, 0,
  60                page_mask_nelts * 3 * sizeof(long));
  61 #endif
  62         return 0;
  63 }
  64
  65 static inline void free_l1stack(void)
  66 {
  67         nr_l1stack_tasks--;
  68         if (nr_l1stack_tasks == 0)
  69                 l1sram_free(l1_stack_base);
  70 }
  71 static inline void destroy_context(struct mm_struct *mm)
  72 {
  73         struct sram_list_struct *tmp;
  74
  75         if (current_l1_stack_save == mm->context.l1_stack_save)
  76                 current_l1_stack_save = NULL;
  77         if (mm->context.l1_stack_save)
  78                 free_l1stack();
  79
  80         while ((tmp = mm->context.sram_list)) {
  81                 mm->context.sram_list = tmp->next;
  82                 sram_free(tmp->addr);
  83                 kfree(tmp);
  84         }
  85 #ifdef CONFIG_MPU
  86         if (current_rwx_mask == mm->context.page_rwx_mask)
  87                 current_rwx_mask = NULL;
  88         free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
  89 #endif
  90 }
  91
  92 static inline unsigned long
  93 alloc_l1stack(unsigned long length, unsigned long *stack_base)
  94 {
  95         if (nr_l1stack_tasks == 0) {
  96                 l1_stack_base = l1sram_alloc_max(&l1_stack_len);
  97                 if (!l1_stack_base)
  98                         return 0;
  99         }
 100
 101         if (l1_stack_len < length) {
 102                 if (nr_l1stack_tasks == 0)
 103                         l1sram_free(l1_stack_base);
 104                 return 0;
 105         }
 106         *stack_base = (unsigned long)l1_stack_base;
 107         nr_l1stack_tasks++;
 108         return l1_stack_len;
 109 }
 110
 111 static inline int
 112 activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
 113 {
 114         if (current_l1_stack_save)
 115                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
 116         mm->context.l1_stack_save = current_l1_stack_save = (void*)sp_base;
 117         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
 118         return 1;
 119 }
 120
 121 #define deactivate_mm(tsk,mm)   do { } while (0)
 122
 123 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
 124
 125 static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
 126                              struct task_struct *tsk)
 127 {
 128         if (prev_mm == next_mm)
 129                 return;
 130 #ifdef CONFIG_MPU
 131         if (prev_mm->context.page_rwx_mask == current_rwx_mask) {
 132                 flush_switched_cplbs();
 133                 set_mask_dcplbs(next_mm->context.page_rwx_mask);
 134         }
 135 #endif
 136
 137         /* L1 stack switching.  */
 138         if (!next_mm->context.l1_stack_save)
 139                 return;
 140         if (next_mm->context.l1_stack_save == current_l1_stack_save)
 141                 return;
 142         if (current_l1_stack_save) {
 143                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
 144         }
 145         current_l1_stack_save = next_mm->context.l1_stack_save;
 146         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
 147 }
 148
 149 #ifdef CONFIG_MPU
 150 static inline void protect_page(struct mm_struct *mm, unsigned long addr,
 151                                 unsigned long flags)
 152 {
 153         unsigned long *mask = mm->context.page_rwx_mask;
 154         unsigned long page = addr >> 12;
 155         unsigned long idx = page >> 5;
 156         unsigned long bit = 1 << (page & 31);
 157
 158         if (flags & VM_MAYREAD)
 159                 mask[idx] |= bit;
 160         else
 161                 mask[idx] &= ~bit;
 162         mask += page_mask_nelts;
 163         if (flags & VM_MAYWRITE)
 164                 mask[idx] |= bit;
 165         else
 166                 mask[idx] &= ~bit;
 167         mask += page_mask_nelts;
 168         if (flags & VM_MAYEXEC)
 169                 mask[idx] |= bit;
 170         else
 171                 mask[idx] &= ~bit;
 172 }
 173
 174 static inline void update_protections(struct mm_struct *mm)
 175 {
 176         if (mm->context.page_rwx_mask == current_rwx_mask) {
 177                 flush_switched_cplbs();
 178                 set_mask_dcplbs(mm->context.page_rwx_mask);
 179         }
 180 }
 181 #endif
 182
 183 #endif