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/memblock.h>
  30 #include <linux/init.h>
  31 #include <linux/delay.h>
  32 #include <linux/blkdev.h>       /* for initrd_* */
  33 #include <linux/pagemap.h>
  34
  35 #include <asm/segment.h>
  36 #include <asm/pgalloc.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/dma.h>
  39 #include <asm/io.h>
  40 #include <asm/tlb.h>
  41 #include <asm/mmu_context.h>
  42 #include <asm/kmap_types.h>
  43 #include <asm/fixmap.h>
  44 #include <asm/tlbflush.h>
  45 #include <asm/sections.h>
  46
  47 int mem_init_done;
  48
  49 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  50
  51 static void __init zone_sizes_init(void)
  52 {
  53         unsigned long zones_size[MAX_NR_ZONES];
  54
  55         /* Clear the zone sizes */
  56         memset(zones_size, 0, sizeof(zones_size));
  57
  58         /*
  59          * We use only ZONE_NORMAL
  60          */
  61         zones_size[ZONE_NORMAL] = max_low_pfn;
  62
  63         free_area_init(zones_size);
  64 }
  65
  66 extern const char _s_kernel_ro[], _e_kernel_ro[];
  67
  68 /*
  69  * Map all physical memory into kernel's address space.
  70  *
  71  * This is explicitly coded for two-level page tables, so if you need
  72  * something else then this needs to change.
  73  */
  74 static void __init map_ram(void)
  75 {
  76         unsigned long v, p, e;
  77         pgprot_t prot;
  78         pgd_t *pge;
  79         pud_t *pue;
  80         pmd_t *pme;
  81         pte_t *pte;
  82         /* These mark extents of read-only kernel pages...
  83          * ...from vmlinux.lds.S
  84          */
  85         struct memblock_region *region;
  86
  87         v = PAGE_OFFSET;
  88
  89         for_each_memblock(memory, region) {
  90                 p = (u32) region->base & PAGE_MASK;
  91                 e = p + (u32) region->size;
  92
  93                 v = (u32) __va(p);
  94                 pge = pgd_offset_k(v);
  95
  96                 while (p < e) {
  97                         int j;
  98                         pue = pud_offset(pge, v);
  99                         pme = pmd_offset(pue, v);
 100
 101                         if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
 102                                 panic("%s: OR1K kernel hardcoded for "
 103                                       "two-level page tables",
 104                                      __func__);
 105                         }
 106
 107                         /* Alloc one page for holding PTE's... */
 108                         pte = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
 109                         if (!pte)
 110                                 panic("%s: Failed to allocate page for PTEs\n",
 111                                       __func__);
 112                         set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte)));
 113
 114                         /* Fill the newly allocated page with PTE'S */
 115                         for (j = 0; p < e && j < PTRS_PER_PTE;
 116                              v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) {
 117                                 if (v >= (u32) _e_kernel_ro ||
 118                                     v < (u32) _s_kernel_ro)
 119                                         prot = PAGE_KERNEL;
 120                                 else
 121                                         prot = PAGE_KERNEL_RO;
 122
 123                                 set_pte(pte, mk_pte_phys(p, prot));
 124                         }
 125
 126                         pge++;
 127                 }
 128
 129                 printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__,
 130                        region->base, region->base + region->size);
 131         }
 132 }
 133
 134 void __init paging_init(void)
 135 {
 136         extern void tlb_init(void);
 137
 138         unsigned long end;
 139         int i;
 140
 141         printk(KERN_INFO "Setting up paging and PTEs.\n");
 142
 143         /* clear out the init_mm.pgd that will contain the kernel's mappings */
 144
 145         for (i = 0; i < PTRS_PER_PGD; i++)
 146                 swapper_pg_dir[i] = __pgd(0);
 147
 148         /* make sure the current pgd table points to something sane
 149          * (even if it is most probably not used until the next
 150          *  switch_mm)
 151          */
 152         current_pgd[smp_processor_id()] = init_mm.pgd;
 153
 154         end = (unsigned long)__va(max_low_pfn * PAGE_SIZE);
 155
 156         map_ram();
 157
 158         zone_sizes_init();
 159
 160         /* self modifying code ;) */
 161         /* Since the old TLB miss handler has been running up until now,
 162          * the kernel pages are still all RW, so we can still modify the
 163          * text directly... after this change and a TLB flush, the kernel
 164          * pages will become RO.
 165          */
 166         {
 167                 extern unsigned long dtlb_miss_handler;
 168                 extern unsigned long itlb_miss_handler;
 169
 170                 unsigned long *dtlb_vector = __va(0x900);
 171                 unsigned long *itlb_vector = __va(0xa00);
 172
 173                 printk(KERN_INFO "itlb_miss_handler %p\n", &itlb_miss_handler);
 174                 *itlb_vector = ((unsigned long)&itlb_miss_handler -
 175                                 (unsigned long)itlb_vector) >> 2;
 176
 177                 /* Soft ordering constraint to ensure that dtlb_vector is
 178                  * the last thing updated
 179                  */
 180                 barrier();
 181
 182                 printk(KERN_INFO "dtlb_miss_handler %p\n", &dtlb_miss_handler);
 183                 *dtlb_vector = ((unsigned long)&dtlb_miss_handler -
 184                                 (unsigned long)dtlb_vector) >> 2;
 185
 186         }
 187
 188         /* Soft ordering constraint to ensure that cache invalidation and
 189          * TLB flush really happen _after_ code has been modified.
 190          */
 191         barrier();
 192
 193         /* Invalidate instruction caches after code modification */
 194         mtspr(SPR_ICBIR, 0x900);
 195         mtspr(SPR_ICBIR, 0xa00);
 196
 197         /* New TLB miss handlers and kernel page tables are in now place.
 198          * Make sure that page flags get updated for all pages in TLB by
 199          * flushing the TLB and forcing all TLB entries to be recreated
 200          * from their page table flags.
 201          */
 202         flush_tlb_all();
 203 }
 204
 205 /* References to section boundaries */
 206
 207 void __init mem_init(void)
 208 {
 209         BUG_ON(!mem_map);
 210
 211         max_mapnr = max_low_pfn;
 212         high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 213
 214         /* clear the zero-page */
 215         memset((void *)empty_zero_page, 0, PAGE_SIZE);
 216
 217         /* this will put all low memory onto the freelists */
 218         memblock_free_all();
 219
 220         mem_init_print_info(NULL);
 221
 222         printk("mem_init_done ...........................................\n");
 223         mem_init_done = 1;
 224         return;
 225 }
 226
 227 #ifdef CONFIG_BLK_DEV_INITRD
 228 void free_initrd_mem(unsigned long start, unsigned long end)
 229 {
 230         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 231 }
 232 #endif
 233
 234 void free_initmem(void)
 235 {
 236         free_initmem_default(-1);
 237 }