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 /* Note: L1 stacks are CPU-private things, so we bluntly disable this
  41    feature in SMP mode, and use the per-CPU scratch SRAM bank only to
  42    store the PDA instead. */
  43
  44 extern void *current_l1_stack_save;
  45 extern int nr_l1stack_tasks;
  46 extern void *l1_stack_base;
  47 extern unsigned long l1_stack_len;
  48
  49 extern int l1sram_free(const void*);
  50 extern void *l1sram_alloc_max(void*);
  51
  52 static inline void free_l1stack(void)
  53 {
  54         nr_l1stack_tasks--;
  55         if (nr_l1stack_tasks == 0)
  56                 l1sram_free(l1_stack_base);
  57 }
  58
  59 static inline unsigned long
  60 alloc_l1stack(unsigned long length, unsigned long *stack_base)
  61 {
  62         if (nr_l1stack_tasks == 0) {
  63                 l1_stack_base = l1sram_alloc_max(&l1_stack_len);
  64                 if (!l1_stack_base)
  65                         return 0;
  66         }
  67
  68         if (l1_stack_len < length) {
  69                 if (nr_l1stack_tasks == 0)
  70                         l1sram_free(l1_stack_base);
  71                 return 0;
  72         }
  73         *stack_base = (unsigned long)l1_stack_base;
  74         nr_l1stack_tasks++;
  75         return l1_stack_len;
  76 }
  77
  78 static inline int
  79 activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
  80 {
  81         if (current_l1_stack_save)
  82                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
  83         mm->context.l1_stack_save = current_l1_stack_save = (void*)sp_base;
  84         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
  85         return 1;
  86 }
  87
  88 #define deactivate_mm(tsk,mm)   do { } while (0)
  89
  90 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
  91
  92 static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
  93                              struct task_struct *tsk)
  94 {
  95 #ifdef CONFIG_MPU
  96         unsigned int cpu = smp_processor_id();
  97 #endif
  98         if (prev_mm == next_mm)
  99                 return;
 100 #ifdef CONFIG_MPU
 101         if (prev_mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
 102                 flush_switched_cplbs(cpu);
 103                 set_mask_dcplbs(next_mm->context.page_rwx_mask, cpu);
 104         }
 105 #endif
 106
 107 #ifdef CONFIG_APP_STACK_L1
 108         /* L1 stack switching.  */
 109         if (!next_mm->context.l1_stack_save)
 110                 return;
 111         if (next_mm->context.l1_stack_save == current_l1_stack_save)
 112                 return;
 113         if (current_l1_stack_save) {
 114                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
 115         }
 116         current_l1_stack_save = next_mm->context.l1_stack_save;
 117         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
 118 #endif
 119 }
 120
 121 #ifdef CONFIG_MPU
 122 static inline void protect_page(struct mm_struct *mm, unsigned long addr,
 123                                 unsigned long flags)
 124 {
 125         unsigned long *mask = mm->context.page_rwx_mask;
 126         unsigned long page = addr >> 12;
 127         unsigned long idx = page >> 5;
 128         unsigned long bit = 1 << (page & 31);
 129
 130         if (flags & VM_MAYREAD)
 131                 mask[idx] |= bit;
 132         else
 133                 mask[idx] &= ~bit;
 134         mask += page_mask_nelts;
 135         if (flags & VM_MAYWRITE)
 136                 mask[idx] |= bit;
 137         else
 138                 mask[idx] &= ~bit;
 139         mask += page_mask_nelts;
 140         if (flags & VM_MAYEXEC)
 141                 mask[idx] |= bit;
 142         else
 143                 mask[idx] &= ~bit;
 144 }
 145
 146 static inline void update_protections(struct mm_struct *mm)
 147 {
 148         unsigned int cpu = smp_processor_id();
 149         if (mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
 150                 flush_switched_cplbs(cpu);
 151                 set_mask_dcplbs(mm->context.page_rwx_mask, cpu);
 152         }
 153 }
 154 #endif
 155
 156 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 157 {
 158 }
 159
 160 /* Called when creating a new context during fork() or execve().  */
 161 static inline int
 162 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 163 {
 164 #ifdef CONFIG_MPU
 165         unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
 166         mm->context.page_rwx_mask = (unsigned long *)p;
 167         memset(mm->context.page_rwx_mask, 0,
 168                page_mask_nelts * 3 * sizeof(long));
 169 #endif
 170         return 0;
 171 }
 172
 173 static inline void destroy_context(struct mm_struct *mm)
 174 {
 175         struct sram_list_struct *tmp;
 176 #ifdef CONFIG_MPU
 177         unsigned int cpu = smp_processor_id();
 178 #endif
 179
 180 #ifdef CONFIG_APP_STACK_L1
 181         if (current_l1_stack_save == mm->context.l1_stack_save)
 182                 current_l1_stack_save = 0;
 183         if (mm->context.l1_stack_save)
 184                 free_l1stack();
 185 #endif
 186
 187         while ((tmp = mm->context.sram_list)) {
 188                 mm->context.sram_list = tmp->next;
 189                 sram_free(tmp->addr);
 190                 kfree(tmp);
 191         }
 192 #ifdef CONFIG_MPU
 193         if (current_rwx_mask[cpu] == mm->context.page_rwx_mask)
 194                 current_rwx_mask[cpu] = NULL;
 195         free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
 196 #endif
 197 }
 198
 199 #endif