arch/tile/kernel/module.c

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * Based on i386 version, copyright (C) 2001 Rusty Russell.
  15  */
  16
  17 #include <linux/moduleloader.h>
  18 #include <linux/elf.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/fs.h>
  21 #include <linux/string.h>
  22 #include <linux/kernel.h>
  23 #include <asm/pgtable.h>
  24 #include <asm/homecache.h>
  25 #include <arch/opcode.h>
  26
  27 #ifdef MODULE_DEBUG
  28 #define DEBUGP printk
  29 #else
  30 #define DEBUGP(fmt...)
  31 #endif
  32
  33 /*
  34  * Allocate some address space in the range MEM_MODULE_START to
  35  * MEM_MODULE_END and populate it with memory.
  36  */
  37 void *module_alloc(unsigned long size)
  38 {
  39         struct page **pages;
  40         pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
  41         struct vm_struct *area;
  42         int i = 0;
  43         int npages;
  44
  45         npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
  46         pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
  47         if (pages == NULL)
  48                 return NULL;
  49         for (; i < npages; ++i) {
  50                 pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
  51                 if (!pages[i])
  52                         goto error;
  53         }
  54
  55         area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
  56         if (!area)
  57                 goto error;
  58         area->nr_pages = npages;
  59         area->pages = pages;
  60
  61         if (map_vm_area(area, prot_rwx, &pages)) {
  62                 vunmap(area->addr);
  63                 goto error;
  64         }
  65
  66         return area->addr;
  67
  68 error:
  69         while (--i >= 0)
  70                 __free_page(pages[i]);
  71         kfree(pages);
  72         return NULL;
  73 }
  74
  75
  76 /* Free memory returned from module_alloc */
  77 void module_free(struct module *mod, void *module_region)
  78 {
  79         vfree(module_region);
  80
  81         /* Globally flush the L1 icache. */
  82         flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
  83                      0, 0, 0, NULL, NULL, 0);
  84
  85         /*
  86          * FIXME: If module_region == mod->module_init, trim exception
  87          * table entries.
  88          */
  89 }
  90
  91 #ifdef __tilegx__
  92 /*
  93  * Validate that the high 16 bits of "value" is just the sign-extension of
  94  * the low 48 bits.
  95  */
  96 static int validate_hw2_last(long value, struct module *me)
  97 {
  98         if (((value << 16) >> 16) != value) {
  99                 pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
 100                            me->name, value);
 101                 return 0;
 102         }
 103         return 1;
 104 }
 105
 106 /*
 107  * Validate that "value" isn't too big to hold in a JumpOff relocation.
 108  */
 109 static int validate_jumpoff(long value)
 110 {
 111         /* Determine size of jump offset. */
 112         int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
 113
 114         /* Check to see if it fits into the relocation slot. */
 115         long f = get_JumpOff_X1(create_JumpOff_X1(value));
 116         f = (f << shift) >> shift;
 117
 118         return f == value;
 119 }
 120 #endif
 121
 122 int apply_relocate_add(Elf_Shdr *sechdrs,
 123                        const char *strtab,
 124                        unsigned int symindex,
 125                        unsigned int relsec,
 126                        struct module *me)
 127 {
 128         unsigned int i;
 129         Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 130         Elf_Sym *sym;
 131         u64 *location;
 132         unsigned long value;
 133
 134         DEBUGP("Applying relocate section %u to %u\n", relsec,
 135                sechdrs[relsec].sh_info);
 136         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 137                 /* This is where to make the change */
 138                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 139                         + rel[i].r_offset;
 140                 /*
 141                  * This is the symbol it is referring to.
 142                  * Note that all undefined symbols have been resolved.
 143                  */
 144                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 145                         + ELF_R_SYM(rel[i].r_info);
 146                 value = sym->st_value + rel[i].r_addend;
 147
 148                 switch (ELF_R_TYPE(rel[i].r_info)) {
 149
 150 #ifdef __LITTLE_ENDIAN
 151 # define MUNGE(func) \
 152         (*location = ((*location & ~func(-1)) | func(value)))
 153 #else
 154 /*
 155  * Instructions are always little-endian, so when we read them as data,
 156  * we have to swap them around before and after modifying them.
 157  */
 158 # define MUNGE(func) \
 159         (*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
 160 #endif
 161
 162 #ifndef __tilegx__
 163                 case R_TILE_32:
 164                         *(uint32_t *)location = value;
 165                         break;
 166                 case R_TILE_IMM16_X0_HA:
 167                         value = (value + 0x8000) >> 16;
 168                         /*FALLTHROUGH*/
 169                 case R_TILE_IMM16_X0_LO:
 170                         MUNGE(create_Imm16_X0);
 171                         break;
 172                 case R_TILE_IMM16_X1_HA:
 173                         value = (value + 0x8000) >> 16;
 174                         /*FALLTHROUGH*/
 175                 case R_TILE_IMM16_X1_LO:
 176                         MUNGE(create_Imm16_X1);
 177                         break;
 178                 case R_TILE_JOFFLONG_X1:
 179                         value -= (unsigned long) location;  /* pc-relative */
 180                         value = (long) value >> 3;     /* count by instrs */
 181                         MUNGE(create_JOffLong_X1);
 182                         break;
 183 #else
 184                 case R_TILEGX_64:
 185                         *location = value;
 186                         break;
 187                 case R_TILEGX_IMM16_X0_HW2_LAST:
 188                         if (!validate_hw2_last(value, me))
 189                                 return -ENOEXEC;
 190                         value >>= 16;
 191                         /*FALLTHROUGH*/
 192                 case R_TILEGX_IMM16_X0_HW1:
 193                         value >>= 16;
 194                         /*FALLTHROUGH*/
 195                 case R_TILEGX_IMM16_X0_HW0:
 196                         MUNGE(create_Imm16_X0);
 197                         break;
 198                 case R_TILEGX_IMM16_X1_HW2_LAST:
 199                         if (!validate_hw2_last(value, me))
 200                                 return -ENOEXEC;
 201                         value >>= 16;
 202                         /*FALLTHROUGH*/
 203                 case R_TILEGX_IMM16_X1_HW1:
 204                         value >>= 16;
 205                         /*FALLTHROUGH*/
 206                 case R_TILEGX_IMM16_X1_HW0:
 207                         MUNGE(create_Imm16_X1);
 208                         break;
 209                 case R_TILEGX_JUMPOFF_X1:
 210                         value -= (unsigned long) location;  /* pc-relative */
 211                         value = (long) value >> 3;     /* count by instrs */
 212                         if (!validate_jumpoff(value)) {
 213                                 pr_warning("module %s: Out of range jump to"
 214                                            " %#llx at %#llx (%p)\n", me->name,
 215                                            sym->st_value + rel[i].r_addend,
 216                                            rel[i].r_offset, location);
 217                                 return -ENOEXEC;
 218                         }
 219                         MUNGE(create_JumpOff_X1);
 220                         break;
 221 #endif
 222
 223 #undef MUNGE
 224
 225                 default:
 226                         pr_err("module %s: Unknown relocation: %d\n",
 227                                me->name, (int) ELF_R_TYPE(rel[i].r_info));
 228                         return -ENOEXEC;
 229                 }
 230         }
 231         return 0;
 232 }