release/src-rt-6.x.4708/linux/linux-2.6.36/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 <asm/setup.h>
  13 #include <asm/page.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/cplbinit.h>
  16 #include <asm/sections.h>
  17
  18 /* Note: L1 stacks are CPU-private things, so we bluntly disable this
  19    feature in SMP mode, and use the per-CPU scratch SRAM bank only to
  20    store the PDA instead. */
  21
  22 extern void *current_l1_stack_save;
  23 extern int nr_l1stack_tasks;
  24 extern void *l1_stack_base;
  25 extern unsigned long l1_stack_len;
  26
  27 extern int l1sram_free(const void*);
  28 extern void *l1sram_alloc_max(void*);
  29
  30 static inline void free_l1stack(void)
  31 {
  32         nr_l1stack_tasks--;
  33         if (nr_l1stack_tasks == 0)
  34                 l1sram_free(l1_stack_base);
  35 }
  36
  37 static inline unsigned long
  38 alloc_l1stack(unsigned long length, unsigned long *stack_base)
  39 {
  40         if (nr_l1stack_tasks == 0) {
  41                 l1_stack_base = l1sram_alloc_max(&l1_stack_len);
  42                 if (!l1_stack_base)
  43                         return 0;
  44         }
  45
  46         if (l1_stack_len < length) {
  47                 if (nr_l1stack_tasks == 0)
  48                         l1sram_free(l1_stack_base);
  49                 return 0;
  50         }
  51         *stack_base = (unsigned long)l1_stack_base;
  52         nr_l1stack_tasks++;
  53         return l1_stack_len;
  54 }
  55
  56 static inline int
  57 activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
  58 {
  59         if (current_l1_stack_save)
  60                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
  61         mm->context.l1_stack_save = current_l1_stack_save = (void*)sp_base;
  62         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
  63         return 1;
  64 }
  65
  66 #define deactivate_mm(tsk,mm)   do { } while (0)
  67
  68 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
  69
  70 static inline void __switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
  71                                struct task_struct *tsk)
  72 {
  73 #ifdef CONFIG_MPU
  74         unsigned int cpu = smp_processor_id();
  75 #endif
  76         if (prev_mm == next_mm)
  77                 return;
  78 #ifdef CONFIG_MPU
  79         if (prev_mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
  80                 flush_switched_cplbs(cpu);
  81                 set_mask_dcplbs(next_mm->context.page_rwx_mask, cpu);
  82         }
  83 #endif
  84
  85 #ifdef CONFIG_APP_STACK_L1
  86         /* L1 stack switching.  */
  87         if (!next_mm->context.l1_stack_save)
  88                 return;
  89         if (next_mm->context.l1_stack_save == current_l1_stack_save)
  90                 return;
  91         if (current_l1_stack_save) {
  92                 memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
  93         }
  94         current_l1_stack_save = next_mm->context.l1_stack_save;
  95         memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
  96 #endif
  97 }
  98
  99 #ifdef CONFIG_IPIPE
 100 #define lock_mm_switch(flags)   local_irq_save_hw_cond(flags)
 101 #define unlock_mm_switch(flags) local_irq_restore_hw_cond(flags)
 102 #else
 103 #define lock_mm_switch(flags)   do { (void)(flags); } while (0)
 104 #define unlock_mm_switch(flags) do { (void)(flags); } while (0)
 105 #endif /* CONFIG_IPIPE */
 106
 107 #ifdef CONFIG_MPU
 108 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 109                              struct task_struct *tsk)
 110 {
 111         unsigned long flags;
 112         lock_mm_switch(flags);
 113         __switch_mm(prev, next, tsk);
 114         unlock_mm_switch(flags);
 115 }
 116
 117 static inline void protect_page(struct mm_struct *mm, unsigned long addr,
 118                                 unsigned long flags)
 119 {
 120         unsigned long *mask = mm->context.page_rwx_mask;
 121         unsigned long page;
 122         unsigned long idx;
 123         unsigned long bit;
 124
 125         if (unlikely(addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE))
 126                 page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> 12;
 127         else
 128                 page = addr >> 12;
 129         idx = page >> 5;
 130         bit = 1 << (page & 31);
 131
 132         if (flags & VM_READ)
 133                 mask[idx] |= bit;
 134         else
 135                 mask[idx] &= ~bit;
 136         mask += page_mask_nelts;
 137         if (flags & VM_WRITE)
 138                 mask[idx] |= bit;
 139         else
 140                 mask[idx] &= ~bit;
 141         mask += page_mask_nelts;
 142         if (flags & VM_EXEC)
 143                 mask[idx] |= bit;
 144         else
 145                 mask[idx] &= ~bit;
 146 }
 147
 148 static inline void update_protections(struct mm_struct *mm)
 149 {
 150         unsigned int cpu = smp_processor_id();
 151         if (mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
 152                 flush_switched_cplbs(cpu);
 153                 set_mask_dcplbs(mm->context.page_rwx_mask, cpu);
 154         }
 155 }
 156 #else /* !CONFIG_MPU */
 157 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 158                              struct task_struct *tsk)
 159 {
 160         __switch_mm(prev, next, tsk);
 161 }
 162 #endif
 163
 164 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 165 {
 166 }
 167
 168 /* Called when creating a new context during fork() or execve().  */
 169 static inline int
 170 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 171 {
 172 #ifdef CONFIG_MPU
 173         unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
 174         mm->context.page_rwx_mask = (unsigned long *)p;
 175         memset(mm->context.page_rwx_mask, 0,
 176                page_mask_nelts * 3 * sizeof(long));
 177 #endif
 178         return 0;
 179 }
 180
 181 static inline void destroy_context(struct mm_struct *mm)
 182 {
 183         struct sram_list_struct *tmp;
 184 #ifdef CONFIG_MPU
 185         unsigned int cpu = smp_processor_id();
 186 #endif
 187
 188 #ifdef CONFIG_APP_STACK_L1
 189         if (current_l1_stack_save == mm->context.l1_stack_save)
 190                 current_l1_stack_save = 0;
 191         if (mm->context.l1_stack_save)
 192                 free_l1stack();
 193 #endif
 194
 195         while ((tmp = mm->context.sram_list)) {
 196                 mm->context.sram_list = tmp->next;
 197                 sram_free(tmp->addr);
 198                 kfree(tmp);
 199         }
 200 #ifdef CONFIG_MPU
 201         if (current_rwx_mask[cpu] == mm->context.page_rwx_mask)
 202                 current_rwx_mask[cpu] = NULL;
 203         free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
 204 #endif
 205 }
 206
 207 #define ipipe_mm_switch_protect(flags)          \
 208         local_irq_save_hw_cond(flags)
 209
 210 #define ipipe_mm_switch_unprotect(flags)        \
 211         local_irq_restore_hw_cond(flags)
 212
 213 #endif