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 __tilegx__
  28 # define Elf_Rela Elf64_Rela
  29 # define ELF_R_SYM ELF64_R_SYM
  30 # define ELF_R_TYPE ELF64_R_TYPE
  31 #else
  32 # define Elf_Rela Elf32_Rela
  33 # define ELF_R_SYM ELF32_R_SYM
  34 # define ELF_R_TYPE ELF32_R_TYPE
  35 #endif
  36
  37 #ifdef MODULE_DEBUG
  38 #define DEBUGP printk
  39 #else
  40 #define DEBUGP(fmt...)
  41 #endif
  42
  43 /*
  44  * Allocate some address space in the range MEM_MODULE_START to
  45  * MEM_MODULE_END and populate it with memory.
  46  */
  47 void *module_alloc(unsigned long size)
  48 {
  49         struct page **pages;
  50         pgprot_t prot_rwx = __pgprot(_PAGE_KERNEL | _PAGE_KERNEL_EXEC);
  51         struct vm_struct *area;
  52         int i = 0;
  53         int npages;
  54
  55         if (size == 0)
  56                 return NULL;
  57         npages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
  58         pages = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
  59         if (pages == NULL)
  60                 return NULL;
  61         for (; i < npages; ++i) {
  62                 pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
  63                 if (!pages[i])
  64                         goto error;
  65         }
  66
  67         area = __get_vm_area(size, VM_ALLOC, MEM_MODULE_START, MEM_MODULE_END);
  68         if (!area)
  69                 goto error;
  70         area->nr_pages = npages;
  71         area->pages = pages;
  72
  73         if (map_vm_area(area, prot_rwx, &pages)) {
  74                 vunmap(area->addr);
  75                 goto error;
  76         }
  77
  78         return area->addr;
  79
  80 error:
  81         while (--i >= 0)
  82                 __free_page(pages[i]);
  83         kfree(pages);
  84         return NULL;
  85 }
  86
  87
  88 /* Free memory returned from module_alloc */
  89 void module_free(struct module *mod, void *module_region)
  90 {
  91         vfree(module_region);
  92
  93         /* Globally flush the L1 icache. */
  94         flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
  95                      0, 0, 0, NULL, NULL, 0);
  96
  97         /*
  98          * FIXME: If module_region == mod->module_init, trim exception
  99          * table entries.
 100          */
 101 }
 102
 103 #ifdef __tilegx__
 104 /*
 105  * Validate that the high 16 bits of "value" is just the sign-extension of
 106  * the low 48 bits.
 107  */
 108 static int validate_hw2_last(long value, struct module *me)
 109 {
 110         if (((value << 16) >> 16) != value) {
 111                 pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
 112                            me->name, value);
 113                 return 0;
 114         }
 115         return 1;
 116 }
 117
 118 /*
 119  * Validate that "value" isn't too big to hold in a JumpOff relocation.
 120  */
 121 static int validate_jumpoff(long value)
 122 {
 123         /* Determine size of jump offset. */
 124         int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
 125
 126         /* Check to see if it fits into the relocation slot. */
 127         long f = get_JumpOff_X1(create_JumpOff_X1(value));
 128         f = (f << shift) >> shift;
 129
 130         return f == value;
 131 }
 132 #endif
 133
 134 int apply_relocate_add(Elf_Shdr *sechdrs,
 135                        const char *strtab,
 136                        unsigned int symindex,
 137                        unsigned int relsec,
 138                        struct module *me)
 139 {
 140         unsigned int i;
 141         Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 142         Elf_Sym *sym;
 143         u64 *location;
 144         unsigned long value;
 145
 146         DEBUGP("Applying relocate section %u to %u\n", relsec,
 147                sechdrs[relsec].sh_info);
 148         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 149                 /* This is where to make the change */
 150                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 151                         + rel[i].r_offset;
 152                 /*
 153                  * This is the symbol it is referring to.
 154                  * Note that all undefined symbols have been resolved.
 155                  */
 156                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 157                         + ELF_R_SYM(rel[i].r_info);
 158                 value = sym->st_value + rel[i].r_addend;
 159
 160                 switch (ELF_R_TYPE(rel[i].r_info)) {
 161
 162 #ifdef __LITTLE_ENDIAN
 163 # define MUNGE(func) \
 164         (*location = ((*location & ~func(-1)) | func(value)))
 165 #else
 166 /*
 167  * Instructions are always little-endian, so when we read them as data,
 168  * we have to swap them around before and after modifying them.
 169  */
 170 # define MUNGE(func) \
 171         (*location = swab64((swab64(*location) & ~func(-1)) | func(value)))
 172 #endif
 173
 174 #ifndef __tilegx__
 175                 case R_TILE_32:
 176                         *(uint32_t *)location = value;
 177                         break;
 178                 case R_TILE_IMM16_X0_HA:
 179                         value = (value + 0x8000) >> 16;
 180                         /*FALLTHROUGH*/
 181                 case R_TILE_IMM16_X0_LO:
 182                         MUNGE(create_Imm16_X0);
 183                         break;
 184                 case R_TILE_IMM16_X1_HA:
 185                         value = (value + 0x8000) >> 16;
 186                         /*FALLTHROUGH*/
 187                 case R_TILE_IMM16_X1_LO:
 188                         MUNGE(create_Imm16_X1);
 189                         break;
 190                 case R_TILE_JOFFLONG_X1:
 191                         value -= (unsigned long) location;  /* pc-relative */
 192                         value = (long) value >> 3;     /* count by instrs */
 193                         MUNGE(create_JOffLong_X1);
 194                         break;
 195 #else
 196                 case R_TILEGX_64:
 197                         *location = value;
 198                         break;
 199                 case R_TILEGX_IMM16_X0_HW2_LAST:
 200                         if (!validate_hw2_last(value, me))
 201                                 return -ENOEXEC;
 202                         value >>= 16;
 203                         /*FALLTHROUGH*/
 204                 case R_TILEGX_IMM16_X0_HW1:
 205                         value >>= 16;
 206                         /*FALLTHROUGH*/
 207                 case R_TILEGX_IMM16_X0_HW0:
 208                         MUNGE(create_Imm16_X0);
 209                         break;
 210                 case R_TILEGX_IMM16_X1_HW2_LAST:
 211                         if (!validate_hw2_last(value, me))
 212                                 return -ENOEXEC;
 213                         value >>= 16;
 214                         /*FALLTHROUGH*/
 215                 case R_TILEGX_IMM16_X1_HW1:
 216                         value >>= 16;
 217                         /*FALLTHROUGH*/
 218                 case R_TILEGX_IMM16_X1_HW0:
 219                         MUNGE(create_Imm16_X1);
 220                         break;
 221                 case R_TILEGX_JUMPOFF_X1:
 222                         value -= (unsigned long) location;  /* pc-relative */
 223                         value = (long) value >> 3;     /* count by instrs */
 224                         if (!validate_jumpoff(value)) {
 225                                 pr_warning("module %s: Out of range jump to"
 226                                            " %#llx at %#llx (%p)\n", me->name,
 227                                            sym->st_value + rel[i].r_addend,
 228                                            rel[i].r_offset, location);
 229                                 return -ENOEXEC;
 230                         }
 231                         MUNGE(create_JumpOff_X1);
 232                         break;
 233 #endif
 234
 235 #undef MUNGE
 236
 237                 default:
 238                         pr_err("module %s: Unknown relocation: %d\n",
 239                                me->name, (int) ELF_R_TYPE(rel[i].r_info));
 240                         return -ENOEXEC;
 241                 }
 242         }
 243         return 0;
 244 }