arch/openrisc/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OpenRISC idle.c
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  */
  13
  14 #include <linux/signal.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/errno.h>
  18 #include <linux/string.h>
  19 #include <linux/types.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/mman.h>
  22 #include <linux/mm.h>
  23 #include <linux/swap.h>
  24 #include <linux/smp.h>
  25 #include <linux/memblock.h>
  26 #include <linux/init.h>
  27 #include <linux/delay.h>
  28 #include <linux/blkdev.h>       /* for initrd_* */
  29 #include <linux/pagemap.h>
  30
  31 #include <asm/pgalloc.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/dma.h>
  34 #include <asm/io.h>
  35 #include <asm/tlb.h>
  36 #include <asm/mmu_context.h>
  37 #include <asm/kmap_types.h>
  38 #include <asm/fixmap.h>
  39 #include <asm/tlbflush.h>
  40 #include <asm/sections.h>
  41
  42 int mem_init_done;
  43
  44 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  45
  46 static void __init zone_sizes_init(void)
  47 {
  48         unsigned long zones_size[MAX_NR_ZONES];
  49
  50         /* Clear the zone sizes */
  51         memset(zones_size, 0, sizeof(zones_size));
  52
  53         /*
  54          * We use only ZONE_NORMAL
  55          */
  56         zones_size[ZONE_NORMAL] = max_low_pfn;
  57
  58         free_area_init(zones_size);
  59 }
  60
  61 extern const char _s_kernel_ro[], _e_kernel_ro[];
  62
  63 /*
  64  * Map all physical memory into kernel's address space.
  65  *
  66  * This is explicitly coded for two-level page tables, so if you need
  67  * something else then this needs to change.
  68  */
  69 static void __init map_ram(void)
  70 {
  71         unsigned long v, p, e;
  72         pgprot_t prot;
  73         pgd_t *pge;
  74         pud_t *pue;
  75         pmd_t *pme;
  76         pte_t *pte;
  77         /* These mark extents of read-only kernel pages...
  78          * ...from vmlinux.lds.S
  79          */
  80         struct memblock_region *region;
  81
  82         v = PAGE_OFFSET;
  83
  84         for_each_memblock(memory, region) {
  85                 p = (u32) region->base & PAGE_MASK;
  86                 e = p + (u32) region->size;
  87
  88                 v = (u32) __va(p);
  89                 pge = pgd_offset_k(v);
  90
  91                 while (p < e) {
  92                         int j;
  93                         pue = pud_offset(pge, v);
  94                         pme = pmd_offset(pue, v);
  95
  96                         if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
  97                                 panic("%s: OR1K kernel hardcoded for "
  98                                       "two-level page tables",
  99                                      __func__);
 100                         }
 101
 102                         /* Alloc one page for holding PTE's... */
 103                         pte = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
 104                         if (!pte)
 105                                 panic("%s: Failed to allocate page for PTEs\n",
 106                                       __func__);
 107                         set_pmd(pme, __pmd(_KERNPG_TABLE + __pa(pte)));
 108
 109                         /* Fill the newly allocated page with PTE'S */
 110                         for (j = 0; p < e && j < PTRS_PER_PTE;
 111                              v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) {
 112                                 if (v >= (u32) _e_kernel_ro ||
 113                                     v < (u32) _s_kernel_ro)
 114                                         prot = PAGE_KERNEL;
 115                                 else
 116                                         prot = PAGE_KERNEL_RO;
 117
 118                                 set_pte(pte, mk_pte_phys(p, prot));
 119                         }
 120
 121                         pge++;
 122                 }
 123
 124                 printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__,
 125                        region->base, region->base + region->size);
 126         }
 127 }
 128
 129 void __init paging_init(void)
 130 {
 131         extern void tlb_init(void);
 132
 133         unsigned long end;
 134         int i;
 135
 136         printk(KERN_INFO "Setting up paging and PTEs.\n");
 137
 138         /* clear out the init_mm.pgd that will contain the kernel's mappings */
 139
 140         for (i = 0; i < PTRS_PER_PGD; i++)
 141                 swapper_pg_dir[i] = __pgd(0);
 142
 143         /* make sure the current pgd table points to something sane
 144          * (even if it is most probably not used until the next
 145          *  switch_mm)
 146          */
 147         current_pgd[smp_processor_id()] = init_mm.pgd;
 148
 149         end = (unsigned long)__va(max_low_pfn * PAGE_SIZE);
 150
 151         map_ram();
 152
 153         zone_sizes_init();
 154
 155         /* self modifying code ;) */
 156         /* Since the old TLB miss handler has been running up until now,
 157          * the kernel pages are still all RW, so we can still modify the
 158          * text directly... after this change and a TLB flush, the kernel
 159          * pages will become RO.
 160          */
 161         {
 162                 extern unsigned long dtlb_miss_handler;
 163                 extern unsigned long itlb_miss_handler;
 164
 165                 unsigned long *dtlb_vector = __va(0x900);
 166                 unsigned long *itlb_vector = __va(0xa00);
 167
 168                 printk(KERN_INFO "itlb_miss_handler %p\n", &itlb_miss_handler);
 169                 *itlb_vector = ((unsigned long)&itlb_miss_handler -
 170                                 (unsigned long)itlb_vector) >> 2;
 171
 172                 /* Soft ordering constraint to ensure that dtlb_vector is
 173                  * the last thing updated
 174                  */
 175                 barrier();
 176
 177                 printk(KERN_INFO "dtlb_miss_handler %p\n", &dtlb_miss_handler);
 178                 *dtlb_vector = ((unsigned long)&dtlb_miss_handler -
 179                                 (unsigned long)dtlb_vector) >> 2;
 180
 181         }
 182
 183         /* Soft ordering constraint to ensure that cache invalidation and
 184          * TLB flush really happen _after_ code has been modified.
 185          */
 186         barrier();
 187
 188         /* Invalidate instruction caches after code modification */
 189         mtspr(SPR_ICBIR, 0x900);
 190         mtspr(SPR_ICBIR, 0xa00);
 191
 192         /* New TLB miss handlers and kernel page tables are in now place.
 193          * Make sure that page flags get updated for all pages in TLB by
 194          * flushing the TLB and forcing all TLB entries to be recreated
 195          * from their page table flags.
 196          */
 197         flush_tlb_all();
 198 }
 199
 200 /* References to section boundaries */
 201
 202 void __init mem_init(void)
 203 {
 204         BUG_ON(!mem_map);
 205
 206         max_mapnr = max_low_pfn;
 207         high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
 208
 209         /* clear the zero-page */
 210         memset((void *)empty_zero_page, 0, PAGE_SIZE);
 211
 212         /* this will put all low memory onto the freelists */
 213         memblock_free_all();
 214
 215         mem_init_print_info(NULL);
 216
 217         printk("mem_init_done ...........................................\n");
 218         mem_init_done = 1;
 219         return;
 220 }