arch/blackfin/include/asm/mmu_context.h

   1 /*
   2  * Copyright 2004-2009 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2 or later.
   5  */
   6
   7 #ifndef __BLACKFIN_MMU_CONTEXT_H__
   8 #define __BLACKFIN_MMU_CONTEXT_H__
   9
  10 #include <linux/slab.h>
  11 #include <linux/sched.h>
  12 #include <linux/mm_types.h>
  13
  14 #include <asm/setup.h>
  15 #include <asm/page.h>
  16 #include <asm/pgalloc.h>
  17 #include <asm/cplbinit.h>
  18 #include <asm/sections.h>
  19
  20 /* Note: L1 stacks are CPU-private things, so we bluntly disable this
  21    feature in SMP mode, and use the per-CPU scratch SRAM bank only to
  22    store the PDA instead. */
  23
  24 extern void *current_l1_stack_save;
  25 extern int nr_l1stack_tasks;
  26 extern void *l1_stack_base;
  27 extern unsigned long l1_stack_len;
  28
  29 extern int l1sram_free(const void*);
  30 extern void *l1sram_alloc_max(void*);
  31
  32 static inline void free_l1stack(void)
  33 {
  34         nr_l1stack_tasks--;
  35         if (nr_l1stack_tasks == 0) {
  36                 l1sram_free(l1_stack_base);
  37                 l1_stack_base = NULL;
  38                 l1_stack_len = 0;
  39         }
  40 }
  41
  42 static inline unsigned long
  43 alloc_l1stack(unsigned long length, unsigned long *stack_base)
  44 {
  45         if (nr_l1stack_tasks == 0) {
  46                 l1_stack_base = l1sram_alloc_max(&l1_stack_len);
  47                 if (!l1_stack_base)
  48                         return 0;
  49         }
  50
  51         if (l1_stack_len < length) {
  52                 if (nr_l1stack_tasks == 0)
  53                         l1sram_free(l1_stack_base);
  54                 return 0;
  55         }
  56         *stack_base = (unsigned long)l1_stack_base;
  57         nr_l1stack_tasks++;
  58         return l1_stack_len;
  59 }
  60
  61 static inline int
  62 activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
  63 {
  64         if (current_l1_stack_save)
  65                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
  66         mm->context.l1_stack_save = current_l1_stack_save = (void*)sp_base;
  67         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
  68         return 1;
  69 }
  70
  71 #define deactivate_mm(tsk,mm)   do { } while (0)
  72
  73 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
  74
  75 static inline void __switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
  76                                struct task_struct *tsk)
  77 {
  78 #ifdef CONFIG_MPU
  79         unsigned int cpu = smp_processor_id();
  80 #endif
  81         if (prev_mm == next_mm)
  82                 return;
  83 #ifdef CONFIG_MPU
  84         if (prev_mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
  85                 flush_switched_cplbs(cpu);
  86                 set_mask_dcplbs(next_mm->context.page_rwx_mask, cpu);
  87         }
  88 #endif
  89
  90 #ifdef CONFIG_APP_STACK_L1
  91         /* L1 stack switching.  */
  92         if (!next_mm->context.l1_stack_save)
  93                 return;
  94         if (next_mm->context.l1_stack_save == current_l1_stack_save)
  95                 return;
  96         if (current_l1_stack_save) {
  97                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
  98         }
  99         current_l1_stack_save = next_mm->context.l1_stack_save;
 100         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
 101 #endif
 102 }
 103
 104 #ifdef CONFIG_IPIPE
 105 #define lock_mm_switch(flags)   flags = hard_local_irq_save_cond()
 106 #define unlock_mm_switch(flags) hard_local_irq_restore_cond(flags)
 107 #else
 108 #define lock_mm_switch(flags)   do { (void)(flags); } while (0)
 109 #define unlock_mm_switch(flags) do { (void)(flags); } while (0)
 110 #endif /* CONFIG_IPIPE */
 111
 112 #ifdef CONFIG_MPU
 113 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 114                              struct task_struct *tsk)
 115 {
 116         unsigned long flags;
 117         lock_mm_switch(flags);
 118         __switch_mm(prev, next, tsk);
 119         unlock_mm_switch(flags);
 120 }
 121
 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;
 127         unsigned long idx;
 128         unsigned long bit;
 129
 130         if (unlikely(addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE))
 131                 page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> 12;
 132         else
 133                 page = addr >> 12;
 134         idx = page >> 5;
 135         bit = 1 << (page & 31);
 136
 137         if (flags & VM_READ)
 138                 mask[idx] |= bit;
 139         else
 140                 mask[idx] &= ~bit;
 141         mask += page_mask_nelts;
 142         if (flags & VM_WRITE)
 143                 mask[idx] |= bit;
 144         else
 145                 mask[idx] &= ~bit;
 146         mask += page_mask_nelts;
 147         if (flags & VM_EXEC)
 148                 mask[idx] |= bit;
 149         else
 150                 mask[idx] &= ~bit;
 151 }
 152
 153 static inline void update_protections(struct mm_struct *mm)
 154 {
 155         unsigned int cpu = smp_processor_id();
 156         if (mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
 157                 flush_switched_cplbs(cpu);
 158                 set_mask_dcplbs(mm->context.page_rwx_mask, cpu);
 159         }
 160 }
 161 #else /* !CONFIG_MPU */
 162 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 163                              struct task_struct *tsk)
 164 {
 165         __switch_mm(prev, next, tsk);
 166 }
 167 #endif
 168
 169 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 170 {
 171 }
 172
 173 /* Called when creating a new context during fork() or execve().  */
 174 static inline int
 175 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 176 {
 177 #ifdef CONFIG_MPU
 178         unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
 179         mm->context.page_rwx_mask = (unsigned long *)p;
 180         memset(mm->context.page_rwx_mask, 0,
 181                page_mask_nelts * 3 * sizeof(long));
 182 #endif
 183         return 0;
 184 }
 185
 186 static inline void destroy_context(struct mm_struct *mm)
 187 {
 188         struct sram_list_struct *tmp;
 189 #ifdef CONFIG_MPU
 190         unsigned int cpu = smp_processor_id();
 191 #endif
 192
 193 #ifdef CONFIG_APP_STACK_L1
 194         if (current_l1_stack_save == mm->context.l1_stack_save)
 195                 current_l1_stack_save = 0;
 196         if (mm->context.l1_stack_save)
 197                 free_l1stack();
 198 #endif
 199
 200         while ((tmp = mm->context.sram_list)) {
 201                 mm->context.sram_list = tmp->next;
 202                 sram_free(tmp->addr);
 203                 kfree(tmp);
 204         }
 205 #ifdef CONFIG_MPU
 206         if (current_rwx_mask[cpu] == mm->context.page_rwx_mask)
 207                 current_rwx_mask[cpu] = NULL;
 208         free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
 209 #endif
 210 }
 211
 212 #define ipipe_mm_switch_protect(flags)          \
 213         flags = hard_local_irq_save_cond()
 214
 215 #define ipipe_mm_switch_unprotect(flags)        \
 216         hard_local_irq_restore_cond(flags)
 217
 218 #endif