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/opcode-tile.h>
  24 #include <asm/pgtable.h>
  25
  26 #ifdef __tilegx__
  27 # define Elf_Rela Elf64_Rela
  28 # define ELF_R_SYM ELF64_R_SYM
  29 # define ELF_R_TYPE ELF64_R_TYPE
  30 #else
  31 # define Elf_Rela Elf32_Rela
  32 # define ELF_R_SYM ELF32_R_SYM
  33 # define ELF_R_TYPE ELF32_R_TYPE
  34 #endif
  35
  36 #ifdef MODULE_DEBUG
  37 #define DEBUGP printk
  38 #else
  39 #define DEBUGP(fmt...)
  40 #endif
  41
  42 /*
  43  * Allocate some address space in the range MEM_MODULE_START to
  44  * MEM_MODULE_END and populate it with memory.
  45  */
  46 void *module_alloc(unsigned long size)
  47 {
  48         struct page **pages;
  49         pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
  50         struct vm_struct *area;
  51         int i = 0;
  52         int npages;
  53
  54         if (size == 0)
  55                 return NULL;
  56         npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
  57         pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
  58         if (pages == NULL)
  59                 return NULL;
  60         for (; i < npages; ++i) {
  61                 pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
  62                 if (!pages[i])
  63                         goto error;
  64         }
  65
  66         area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
  67         if (!area)
  68                 goto error;
  69
  70         if (map_vm_area(area, prot_rwx, &pages)) {
  71                 vunmap(area->addr);
  72                 goto error;
  73         }
  74
  75         return area->addr;
  76
  77 error:
  78         while (--i >= 0)
  79                 __free_page(pages[i]);
  80         kfree(pages);
  81         return NULL;
  82 }
  83
  84
  85 /* Free memory returned from module_alloc */
  86 void module_free(struct module *mod, void *module_region)
  87 {
  88         vfree(module_region);
  89         /*
  90          * FIXME: If module_region == mod->init_region, trim exception
  91          * table entries.
  92          */
  93 }
  94
  95 /* We don't need anything special. */
  96 int module_frob_arch_sections(Elf_Ehdr *hdr,
  97                               Elf_Shdr *sechdrs,
  98                               char *secstrings,
  99                               struct module *mod)
 100 {
 101         return 0;
 102 }
 103
 104 int apply_relocate(Elf_Shdr *sechdrs,
 105                    const char *strtab,
 106                    unsigned int symindex,
 107                    unsigned int relsec,
 108                    struct module *me)
 109 {
 110         pr_err("module %s: .rel relocation unsupported\n", me->name);
 111         return -ENOEXEC;
 112 }
 113
 114 #ifdef __tilegx__
 115 /*
 116  * Validate that the high 16 bits of "value" is just the sign-extension of
 117  * the low 48 bits.
 118  */
 119 static int validate_hw2_last(long value, struct module *me)
 120 {
 121         if (((value << 16) >> 16) != value) {
 122                 pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
 123                            me->name, value);
 124                 return 0;
 125         }
 126         return 1;
 127 }
 128
 129 /*
 130  * Validate that "value" isn't too big to hold in a JumpOff relocation.
 131  */
 132 static int validate_jumpoff(long value)
 133 {
 134         /* Determine size of jump offset. */
 135         int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
 136
 137         /* Check to see if it fits into the relocation slot. */
 138         long f = get_JumpOff_X1(create_JumpOff_X1(value));
 139         f = (f << shift) >> shift;
 140
 141         return f == value;
 142 }
 143 #endif
 144
 145 int apply_relocate_add(Elf_Shdr *sechdrs,
 146                        const char *strtab,
 147                        unsigned int symindex,
 148                        unsigned int relsec,
 149                        struct module *me)
 150 {
 151         unsigned int i;
 152         Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 153         Elf_Sym *sym;
 154         u64 *location;
 155         unsigned long value;
 156
 157         DEBUGP("Applying relocate section %u to %u\n", relsec,
 158                sechdrs[relsec].sh_info);
 159         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 160                 /* This is where to make the change */
 161                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 162                         + rel[i].r_offset;
 163                 /*
 164                  * This is the symbol it is referring to.
 165                  * Note that all undefined symbols have been resolved.
 166                  */
 167                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 168                         + ELF_R_SYM(rel[i].r_info);
 169                 value = sym->st_value + rel[i].r_addend;
 170
 171                 switch (ELF_R_TYPE(rel[i].r_info)) {
 172
 173 #define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
 174
 175 #ifndef __tilegx__
 176                 case R_TILE_32:
 177                         *(uint32_t *)location = value;
 178                         break;
 179                 case R_TILE_IMM16_X0_HA:
 180                         value = (value + 0x8000) >> 16;
 181                         /*FALLTHROUGH*/
 182                 case R_TILE_IMM16_X0_LO:
 183                         MUNGE(create_Imm16_X0);
 184                         break;
 185                 case R_TILE_IMM16_X1_HA:
 186                         value = (value + 0x8000) >> 16;
 187                         /*FALLTHROUGH*/
 188                 case R_TILE_IMM16_X1_LO:
 189                         MUNGE(create_Imm16_X1);
 190                         break;
 191                 case R_TILE_JOFFLONG_X1:
 192                         value -= (unsigned long) location;  /* pc-relative */
 193                         value = (long) value >> 3;     /* count by instrs */
 194                         MUNGE(create_JOffLong_X1);
 195                         break;
 196 #else
 197                 case R_TILEGX_64:
 198                         *location = value;
 199                         break;
 200                 case R_TILEGX_IMM16_X0_HW2_LAST:
 201                         if (!validate_hw2_last(value, me))
 202                                 return -ENOEXEC;
 203                         value >>= 16;
 204                         /*FALLTHROUGH*/
 205                 case R_TILEGX_IMM16_X0_HW1:
 206                         value >>= 16;
 207                         /*FALLTHROUGH*/
 208                 case R_TILEGX_IMM16_X0_HW0:
 209                         MUNGE(create_Imm16_X0);
 210                         break;
 211                 case R_TILEGX_IMM16_X1_HW2_LAST:
 212                         if (!validate_hw2_last(value, me))
 213                                 return -ENOEXEC;
 214                         value >>= 16;
 215                         /*FALLTHROUGH*/
 216                 case R_TILEGX_IMM16_X1_HW1:
 217                         value >>= 16;
 218                         /*FALLTHROUGH*/
 219                 case R_TILEGX_IMM16_X1_HW0:
 220                         MUNGE(create_Imm16_X1);
 221                         break;
 222                 case R_TILEGX_JUMPOFF_X1:
 223                         value -= (unsigned long) location;  /* pc-relative */
 224                         value = (long) value >> 3;     /* count by instrs */
 225                         if (!validate_jumpoff(value)) {
 226                                 pr_warning("module %s: Out of range jump to"
 227                                            " %#llx at %#llx (%p)\n", me->name,
 228                                            sym->st_value + rel[i].r_addend,
 229                                            rel[i].r_offset, location);
 230                                 return -ENOEXEC;
 231                         }
 232                         MUNGE(create_JumpOff_X1);
 233                         break;
 234 #endif
 235
 236 #undef MUNGE
 237
 238                 default:
 239                         pr_err("module %s: Unknown relocation: %d\n",
 240                                me->name, (int) ELF_R_TYPE(rel[i].r_info));
 241                         return -ENOEXEC;
 242                 }
 243         }
 244         return 0;
 245 }
 246
 247 int module_finalize(const Elf_Ehdr *hdr,
 248                     const Elf_Shdr *sechdrs,
 249                     struct module *me)
 250 {
 251         /* FIXME: perhaps remove the "writable" bit from the TLB? */
 252         return 0;
 253 }
 254
 255 void module_arch_cleanup(struct module *mod)
 256 {
 257 }