target/linux/coldfire/files-2.6.31/arch/m68k/mm/cf-mmu.c

   1 /*
   2  * linux/arch/m68k/mm/cf-mmu.c
   3  *
   4  * Based upon linux/arch/m68k/mm/sun3mmu.c
   5  * Based upon linux/arch/ppc/mm/mmu_context.c
   6  *
   7  * Implementations of mm routines specific to the Coldfire MMU.
   8  *
   9  * Copyright (c) 2008 Freescale Semiconductor, Inc.
  10  * Copyright Freescale Semiconductor, Inc. 2008-2009
  11  *   Jason Jin Jason.Jin@freescale.com
  12  *   Shrek Wu B16972@freescale.com
  13  */
  14
  15 #include <linux/signal.h>
  16 #include <linux/sched.h>
  17 #include <linux/mm.h>
  18 #include <linux/swap.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/types.h>
  22 #include <linux/init.h>
  23 #ifdef CONFIG_BLK_DEV_RAM
  24 #include <linux/blkdev.h>
  25 #endif
  26 #include <linux/bootmem.h>
  27
  28 #include <asm/setup.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/page.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/system.h>
  33 #include <asm/machdep.h>
  34 #include <asm/io.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/cf_pgalloc.h>
  37
  38 #include <asm/coldfire.h>
  39 #include <asm/tlbflush.h>
  40
  41 #define KMAPAREA(x)     ((x >= VMALLOC_START) && (x < KMAP_END))
  42
  43 #undef DEBUG
  44
  45 #ifdef CONFIG_VDSO
  46 unsigned long next_mmu_context;
  47 #else
  48 mm_context_t next_mmu_context;
  49 #endif
  50
  51 unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
  52
  53 atomic_t nr_free_contexts;
  54 struct mm_struct *context_mm[LAST_CONTEXT+1];
  55 void steal_context(void);
  56 #ifdef CONFIG_M5445X
  57 void m68k_setup_node(int);
  58 #endif
  59 const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
  60
  61 extern unsigned long empty_bad_page_table;
  62 extern unsigned long empty_bad_page;
  63 extern unsigned long num_pages;
  64 #ifdef CONFIG_M5445X
  65 extern unsigned long availmem;
  66 #endif
  67 extern char __init_begin, __init_end;
  68
  69 /*
  70  * Free memory used for system initialization.
  71  */
  72 void free_initmem(void)
  73 {
  74 #if 0
  75         unsigned long addr;
  76         unsigned long start = (unsigned long)&__init_begin;
  77         unsigned long end = (unsigned long)&__init_end;
  78
  79         printk(KERN_INFO "free_initmem: __init_begin = 0x%lx  __init_end = 0x%lx\n", start, end);
  80
  81         addr = (unsigned long)&__init_begin;
  82         for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
  83                 /* not currently used */
  84                 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
  85                 init_page_count(virt_to_page(addr));
  86                 free_page(addr);
  87                 totalram_pages++;
  88         }
  89 #endif
  90 }
  91
  92 /*
  93  * Initialize the paging system.
  94  */
  95 void __init paging_init(void)
  96 {
  97         pgd_t * pg_dir;
  98         pte_t * pg_table;
  99         int i;
 100         unsigned long address;
 101         unsigned long next_pgtable;
 102         unsigned long zones_size[MAX_NR_ZONES];
 103         unsigned long size;
 104         enum zone_type zone;
 105
 106         /* allocate zero page */
 107         empty_zero_page = (void *)alloc_bootmem_pages(PAGE_SIZE);
 108         memset((void *)empty_zero_page, 0, PAGE_SIZE);
 109
 110         /* zero kernel page directory */
 111         pg_dir = swapper_pg_dir;
 112         memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
 113         /*
 114          * setup page tables for PHYSRAM
 115          */
 116
 117         /* starting loc in page directory */
 118         pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
 119
 120         /* allocate page tables */
 121         size = num_pages * sizeof(pte_t);
 122         size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
 123         next_pgtable = (unsigned long)alloc_bootmem_pages(size);
 124         address = PAGE_OFFSET;
 125         while (address < (unsigned long)high_memory) {
 126                 /* setup page table in page directory */
 127                 pg_table = (pte_t *)next_pgtable;
 128                 next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
 129                 pgd_val(*pg_dir) = (unsigned long)pg_table;
 130                 pg_dir++;
 131
 132                 /* create PTEs in page table */
 133                 for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
 134                         pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
 135                         if (address >= (unsigned long)high_memory)
 136                                 pte_val (pte) = 0;
 137
 138                         set_pte(pg_table, pte);
 139                         address += PAGE_SIZE;
 140                 }
 141         }
 142
 143         /*
 144          * setup page tables for DMA area
 145          */
 146
 147         /* starting loc in page directory */
 148         pg_dir = swapper_pg_dir;
 149         pg_dir += CONFIG_DMA_BASE >> PGDIR_SHIFT;
 150
 151         /* allocate page tables */
 152         size = (CONFIG_DMA_SIZE >> PAGE_SHIFT) * sizeof(pte_t);
 153         size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
 154         next_pgtable = (unsigned long)alloc_bootmem_pages(size);
 155         address = CONFIG_DMA_BASE;
 156         while (address < (CONFIG_DMA_BASE + CONFIG_DMA_SIZE)) {
 157                 /* setup page table in page directory */
 158                 pg_table = (pte_t *)next_pgtable;
 159                 next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
 160                 pgd_val(*pg_dir) = (unsigned long)pg_table;
 161                 pg_dir++;
 162
 163                 /* create PTEs in page table */
 164                 for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
 165                         pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
 166                         if (address >= (CONFIG_DMA_BASE + CONFIG_DMA_SIZE))
 167                                 pte_val (pte) = 0;
 168
 169                         set_pte(pg_table, pte);
 170                         address += PAGE_SIZE;
 171                 }
 172         }
 173
 174         /*
 175          * setup zones
 176          */
 177
 178         current->mm = NULL;
 179
 180         /* clear zones */
 181         for (zone = 0; zone < MAX_NR_ZONES; zone++)
 182                 zones_size[zone] = 0x0;
 183
 184         zones_size[ZONE_DMA] = CONFIG_DMA_SIZE >> PAGE_SHIFT;
 185         zones_size[ZONE_NORMAL] = (((unsigned long)high_memory -
 186                                     PAGE_OFFSET) >> PAGE_SHIFT) -
 187                                    zones_size[ZONE_DMA];
 188
 189         free_area_init(zones_size);
 190 }
 191 /*
 192  * Handle a missed TLB
 193  */
 194 int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
 195 {
 196         struct mm_struct *mm;
 197         pgd_t *pgd;
 198         pmd_t *pmd;
 199         pte_t *pte;
 200         unsigned long mmuar;
 201         int asid;
 202         int flags;
 203
 204         local_save_flags(flags);
 205         local_irq_disable();
 206
 207         mmuar = ( dtlb ) ? regs->mmuar
 208                          : regs->pc + (extension_word * sizeof(long));
 209
 210         mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
 211
 212         if (!mm) {
 213             local_irq_restore(flags);
 214             return (-1);
 215         }
 216
 217         pgd = pgd_offset(mm, mmuar);
 218         if (pgd_none(*pgd))  {
 219             local_irq_restore(flags);
 220             return (-1);
 221         }
 222
 223         pmd = pmd_offset(pgd, mmuar);
 224         if (pmd_none(*pmd)) {
 225             local_irq_restore(flags);
 226             return (-1);
 227         }
 228
 229         pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
 230                                : pte_offset_map(pmd, mmuar);
 231         if (pte_none(*pte) || !pte_present(*pte)) {
 232             local_irq_restore(flags);
 233             return (-1);
 234         }
 235
 236         if (write) {
 237             if (!pte_write(*pte)) {
 238                 local_irq_restore(flags);
 239                 return (-1);
 240             }
 241             set_pte(pte, pte_mkdirty(*pte));
 242         }
 243
 244         set_pte(pte, pte_mkyoung(*pte));
 245         asid = cpu_context(mm) & 0xff;
 246         if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
 247             set_pte(pte, pte_wrprotect(*pte));
 248
 249         *MMUTR = (mmuar & PAGE_MASK) | (asid << CF_ASID_MMU_SHIFT)
 250                | (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK ) >> CF_PAGE_MMUTR_SHIFT)
 251                | MMUTR_V;
 252
 253         *MMUDR = (pte_val(*pte) & PAGE_MASK)
 254                | ((pte->pte) & CF_PAGE_MMUDR_MASK)
 255                | MMUDR_SZ8K | MMUDR_X;
 256
 257         if ( dtlb )
 258             *MMUOR = MMUOR_ACC | MMUOR_UAA;
 259         else
 260             *MMUOR = MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA;
 261
 262         asm("nop");
 263
 264 #ifdef DEBUG
 265         printk("cf_tlb_miss: va=%lx, pa=%lx\n", (mmuar & PAGE_MASK),
 266                   (pte_val(*pte)  & PAGE_MASK));
 267 #endif
 268         local_irq_restore(flags);
 269         return (0);
 270 }
 271
 272
 273 /*
 274  * Context Management
 275  *
 276  * Based on arch/ppc/mmu_context.c
 277  */
 278
 279 /*
 280  * Initialize the context management system.
 281  */
 282 void __init mmu_context_init(void)
 283 {
 284         /*
 285          * Some processors have too few contexts to reserve one for
 286          * init_mm, and require using context 0 for a normal task.
 287          * Other processors reserve the use of context zero for the kernel.
 288          * This code assumes FIRST_CONTEXT < 32.
 289          */
 290         context_map[0] = (1 << FIRST_CONTEXT) - 1;
 291         next_mmu_context = FIRST_CONTEXT;
 292         atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
 293 }
 294
 295 /*
 296  * Steal a context from a task that has one at the moment.
 297  * This is only used on 8xx and 4xx and we presently assume that
 298  * they don't do SMP.  If they do then thicfpgalloc.hs will have to check
 299  * whether the MM we steal is in use.
 300  * We also assume that this is only used on systems that don't
 301  * use an MMU hash table - this is true for 8xx and 4xx.
 302  * This isn't an LRU system, it just frees up each context in
 303  * turn (sort-of pseudo-random replacement :).  This would be the
 304  * place to implement an LRU scheme if anyone was motivated to do it.
 305  *  -- paulus
 306  */
 307 void steal_context(void)
 308 {
 309         struct mm_struct *mm;
 310         /* free up context `next_mmu_context' */
 311         /* if we shouldn't free context 0, don't... */
 312         if (next_mmu_context < FIRST_CONTEXT)
 313                 next_mmu_context = FIRST_CONTEXT;
 314         mm = context_mm[next_mmu_context];
 315         flush_tlb_mm(mm);
 316         destroy_context(mm);
 317 }