arch/openrisc/mm/init.c

   1 /*
   2  * OpenRISC idle.c
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * Modifications for the OpenRISC architecture:
   9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 #include <linux/signal.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/errno.h>
  22 #include <linux/string.h>
  23 #include <linux/types.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/mman.h>
  26 #include <linux/mm.h>
  27 #include <linux/swap.h>
  28 #include <linux/smp.h>
  29 #include <linux/bootmem.h>
  30 #include <linux/init.h>
  31 #include <linux/delay.h>
  32 #include <linux/blkdev.h>       /* for initrd_* */
  33 #include <linux/pagemap.h>
  34 #include <linux/memblock.h>
  35
  36 #include <asm/segment.h>
  37 #include <asm/pgalloc.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/dma.h>
  40 #include <asm/io.h>
  41 #include <asm/tlb.h>
  42 #include <asm/mmu_context.h>
  43 #include <asm/kmap_types.h>
  44 #include <asm/fixmap.h>
  45 #include <asm/tlbflush.h>
  46 #include <asm/sections.h>
  47
  48 int mem_init_done;
  49
  50 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  51
  52 static void __init zone_sizes_init(void)
  53 {
  54         unsigned long zones_size[MAX_NR_ZONES];
  55
  56         /* Clear the zone sizes */
  57         memset(zones_size, 0, sizeof(zones_size));
  58
  59         /*
  60          * We use only ZONE_NORMAL
  61          */
  62         zones_size[ZONE_NORMAL] = max_low_pfn;
  63
  64         free_area_init(zones_size);
  65 }
  66
  67 extern const char _s_kernel_ro[], _e_kernel_ro[];
  68
  69 /*
  70  * Map all physical memory into kernel's address space.
  71  *
  72  * This is explicitly coded for two-level page tables, so if you need
  73  * something else then this needs to change.
  74  */
  75 static void __init map_ram(void)
  76 {
  77         unsigned long v, p, e;
  78         pgprot_t prot;
  79         pgd_t *pge;
  80         pud_t *pue;
  81         pmd_t *pme;
  82         pte_t *pte;
  83         /* These mark extents of read-only kernel pages...
  84          * ...from vmlinux.lds.S
  85          */
  86         struct memblock_region *region;
  87
  88         v = PAGE_OFFSET;
  89
  90         for_each_memblock(memory, region) {
  91                 p = (u32) region->base & PAGE_MASK;
  92                 e = p + (u32) region->size;
  93
  94                 v = (u32) __va(p);
  95                 pge = pgd_offset_k(v);
  96
  97                 while (p < e) {
  98                         int j;
  99                         pue = pud_offset(pge, v);
 100                         pme = pmd_offset(pue, v);
 101
 102                         if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
 103                                 panic("%s: OR1K kernel hardcoded for "
 104                                       "two-level page tables",
 105                                      __func__);
 106                         }
 107
 108                         /* Alloc one page for holding PTE's... */
 109                         pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 110                         set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte)));
 111
 112                         /* Fill the newly allocated page with PTE'S */
 113                         for (j = 0; p < e && j < PTRS_PER_PGD;
 114                              v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) {
 115                                 if (v >= (u32) _e_kernel_ro ||
 116                                     v < (u32) _s_kernel_ro)
 117                                         prot = PAGE_KERNEL;
 118                                 else
 119                                         prot = PAGE_KERNEL_RO;
 120
 121                                 set_pte(pte, mk_pte_phys(p, prot));
 122                         }
 123
 124                         pge++;
 125                 }
 126
 127                 printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__,
 128                        region->base, region->base + region->size);
 129         }
 130 }
 131
 132 void __init paging_init(void)
 133 {
 134         extern void tlb_init(void);
 135
 136         unsigned long end;
 137         int i;
 138
 139         printk(KERN_INFO "Setting up paging and PTEs.\n");
 140
 141         /* clear out the init_mm.pgd that will contain the kernel's mappings */
 142
 143         for (i = 0; i < PTRS_PER_PGD; i++)
 144                 swapper_pg_dir[i] = __pgd(0);
 145
 146         /* make sure the current pgd table points to something sane
 147          * (even if it is most probably not used until the next
 148          *  switch_mm)
 149          */
 150         current_pgd = init_mm.pgd;
 151
 152         end = (unsigned long)__va(max_low_pfn * PAGE_SIZE);
 153
 154         map_ram();
 155
 156         zone_sizes_init();
 157
 158         /* self modifying code ;) */
 159         /* Since the old TLB miss handler has been running up until now,
 160          * the kernel pages are still all RW, so we can still modify the
 161          * text directly... after this change and a TLB flush, the kernel
 162          * pages will become RO.
 163          */
 164         {
 165                 extern unsigned long dtlb_miss_handler;
 166                 extern unsigned long itlb_miss_handler;
 167
 168                 unsigned long *dtlb_vector = __va(0x900);
 169                 unsigned long *itlb_vector = __va(0xa00);
 170
 171                 printk(KERN_INFO "itlb_miss_handler %p\n", &itlb_miss_handler);
 172                 *itlb_vector = ((unsigned long)&itlb_miss_handler -
 173                                 (unsigned long)itlb_vector) >> 2;
 174
 175                 /* Soft ordering constraint to ensure that dtlb_vector is
 176                  * the last thing updated
 177                  */
 178                 barrier();
 179
 180                 printk(KERN_INFO "dtlb_miss_handler %p\n", &dtlb_miss_handler);
 181                 *dtlb_vector = ((unsigned long)&dtlb_miss_handler -
 182                                 (unsigned long)dtlb_vector) >> 2;
 183
 184         }
 185
 186         /* Soft ordering constraint to ensure that cache invalidation and
 187          * TLB flush really happen _after_ code has been modified.
 188          */
 189         barrier();
 190
 191         /* Invalidate instruction caches after code modification */
 192         mtspr(SPR_ICBIR, 0x900);
 193         mtspr(SPR_ICBIR, 0xa00);
 194
 195         /* New TLB miss handlers and kernel page tables are in now place.
 196          * Make sure that page flags get updated for all pages in TLB by
 197          * flushing the TLB and forcing all TLB entries to be recreated
 198          * from their page table flags.
 199          */
 200         flush_tlb_all();
 201 }
 202
 203 /* References to section boundaries */
 204
 205 void __init mem_init(void)
 206 {
 207         BUG_ON(!mem_map);
 208
 209         max_mapnr = max_low_pfn;
 210         high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 211
 212         /* clear the zero-page */
 213         memset((void *)empty_zero_page, 0, PAGE_SIZE);
 214
 215         /* this will put all low memory onto the freelists */
 216         free_all_bootmem();
 217
 218         mem_init_print_info(NULL);
 219
 220         printk("mem_init_done ...........................................\n");
 221         mem_init_done = 1;
 222         return;
 223 }
 224
 225 #ifdef CONFIG_BLK_DEV_INITRD
 226 void free_initrd_mem(unsigned long start, unsigned long end)
 227 {
 228         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 229 }
 230 #endif
 231
 232 void free_initmem(void)
 233 {
 234         free_initmem_default(-1);
 235 }