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 #include <asm/homecache.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
  71         if (map_vm_area(area, prot_rwx, &pages)) {
  72                 vunmap(area->addr);
  73                 goto error;
  74         }
  75
  76         return area->addr;
  77
  78 error:
  79         while (--i >= 0)
  80                 __free_page(pages[i]);
  81         kfree(pages);
  82         return NULL;
  83 }
  84
  85
  86 /* Free memory returned from module_alloc */
  87 void module_free(struct module *mod, void *module_region)
  88 {
  89         vfree(module_region);
  90
  91         /* Globally flush the L1 icache. */
  92         flush_remote(0, HV_FLUSH_EVICT_L1I, cpu_online_mask,
  93                      0, 0, 0, NULL, NULL, 0);
  94
  95         /*
  96          * FIXME: If module_region == mod->module_init, trim exception
  97          * table entries.
  98          */
  99 }
 100
 101 #ifdef __tilegx__
 102 /*
 103  * Validate that the high 16 bits of "value" is just the sign-extension of
 104  * the low 48 bits.
 105  */
 106 static int validate_hw2_last(long value, struct module *me)
 107 {
 108         if (((value << 16) >> 16) != value) {
 109                 pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
 110                            me->name, value);
 111                 return 0;
 112         }
 113         return 1;
 114 }
 115
 116 /*
 117  * Validate that "value" isn't too big to hold in a JumpOff relocation.
 118  */
 119 static int validate_jumpoff(long value)
 120 {
 121         /* Determine size of jump offset. */
 122         int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
 123
 124         /* Check to see if it fits into the relocation slot. */
 125         long f = get_JumpOff_X1(create_JumpOff_X1(value));
 126         f = (f << shift) >> shift;
 127
 128         return f == value;
 129 }
 130 #endif
 131
 132 int apply_relocate_add(Elf_Shdr *sechdrs,
 133                        const char *strtab,
 134                        unsigned int symindex,
 135                        unsigned int relsec,
 136                        struct module *me)
 137 {
 138         unsigned int i;
 139         Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 140         Elf_Sym *sym;
 141         u64 *location;
 142         unsigned long value;
 143
 144         DEBUGP("Applying relocate section %u to %u\n", relsec,
 145                sechdrs[relsec].sh_info);
 146         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 147                 /* This is where to make the change */
 148                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 149                         + rel[i].r_offset;
 150                 /*
 151                  * This is the symbol it is referring to.
 152                  * Note that all undefined symbols have been resolved.
 153                  */
 154                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 155                         + ELF_R_SYM(rel[i].r_info);
 156                 value = sym->st_value + rel[i].r_addend;
 157
 158                 switch (ELF_R_TYPE(rel[i].r_info)) {
 159
 160 #define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
 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 }