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 /* We don't need anything special. */
 102 int module_frob_arch_sections(Elf_Ehdr *hdr,
 103                               Elf_Shdr *sechdrs,
 104                               char *secstrings,
 105                               struct module *mod)
 106 {
 107         return 0;
 108 }
 109
 110 int apply_relocate(Elf_Shdr *sechdrs,
 111                    const char *strtab,
 112                    unsigned int symindex,
 113                    unsigned int relsec,
 114                    struct module *me)
 115 {
 116         pr_err("module %s: .rel relocation unsupported\n", me->name);
 117         return -ENOEXEC;
 118 }
 119
 120 #ifdef __tilegx__
 121 /*
 122  * Validate that the high 16 bits of "value" is just the sign-extension of
 123  * the low 48 bits.
 124  */
 125 static int validate_hw2_last(long value, struct module *me)
 126 {
 127         if (((value << 16) >> 16) != value) {
 128                 pr_warning("module %s: Out of range HW2_LAST value %#lx\n",
 129                            me->name, value);
 130                 return 0;
 131         }
 132         return 1;
 133 }
 134
 135 /*
 136  * Validate that "value" isn't too big to hold in a JumpOff relocation.
 137  */
 138 static int validate_jumpoff(long value)
 139 {
 140         /* Determine size of jump offset. */
 141         int shift = __builtin_clzl(get_JumpOff_X1(create_JumpOff_X1(-1)));
 142
 143         /* Check to see if it fits into the relocation slot. */
 144         long f = get_JumpOff_X1(create_JumpOff_X1(value));
 145         f = (f << shift) >> shift;
 146
 147         return f == value;
 148 }
 149 #endif
 150
 151 int apply_relocate_add(Elf_Shdr *sechdrs,
 152                        const char *strtab,
 153                        unsigned int symindex,
 154                        unsigned int relsec,
 155                        struct module *me)
 156 {
 157         unsigned int i;
 158         Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 159         Elf_Sym *sym;
 160         u64 *location;
 161         unsigned long value;
 162
 163         DEBUGP("Applying relocate section %u to %u\n", relsec,
 164                sechdrs[relsec].sh_info);
 165         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 166                 /* This is where to make the change */
 167                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 168                         + rel[i].r_offset;
 169                 /*
 170                  * This is the symbol it is referring to.
 171                  * Note that all undefined symbols have been resolved.
 172                  */
 173                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 174                         + ELF_R_SYM(rel[i].r_info);
 175                 value = sym->st_value + rel[i].r_addend;
 176
 177                 switch (ELF_R_TYPE(rel[i].r_info)) {
 178
 179 #define MUNGE(func) (*location = ((*location & ~func(-1)) | func(value)))
 180
 181 #ifndef __tilegx__
 182                 case R_TILE_32:
 183                         *(uint32_t *)location = value;
 184                         break;
 185                 case R_TILE_IMM16_X0_HA:
 186                         value = (value + 0x8000) >> 16;
 187                         /*FALLTHROUGH*/
 188                 case R_TILE_IMM16_X0_LO:
 189                         MUNGE(create_Imm16_X0);
 190                         break;
 191                 case R_TILE_IMM16_X1_HA:
 192                         value = (value + 0x8000) >> 16;
 193                         /*FALLTHROUGH*/
 194                 case R_TILE_IMM16_X1_LO:
 195                         MUNGE(create_Imm16_X1);
 196                         break;
 197                 case R_TILE_JOFFLONG_X1:
 198                         value -= (unsigned long) location;  /* pc-relative */
 199                         value = (long) value >> 3;     /* count by instrs */
 200                         MUNGE(create_JOffLong_X1);
 201                         break;
 202 #else
 203                 case R_TILEGX_64:
 204                         *location = value;
 205                         break;
 206                 case R_TILEGX_IMM16_X0_HW2_LAST:
 207                         if (!validate_hw2_last(value, me))
 208                                 return -ENOEXEC;
 209                         value >>= 16;
 210                         /*FALLTHROUGH*/
 211                 case R_TILEGX_IMM16_X0_HW1:
 212                         value >>= 16;
 213                         /*FALLTHROUGH*/
 214                 case R_TILEGX_IMM16_X0_HW0:
 215                         MUNGE(create_Imm16_X0);
 216                         break;
 217                 case R_TILEGX_IMM16_X1_HW2_LAST:
 218                         if (!validate_hw2_last(value, me))
 219                                 return -ENOEXEC;
 220                         value >>= 16;
 221                         /*FALLTHROUGH*/
 222                 case R_TILEGX_IMM16_X1_HW1:
 223                         value >>= 16;
 224                         /*FALLTHROUGH*/
 225                 case R_TILEGX_IMM16_X1_HW0:
 226                         MUNGE(create_Imm16_X1);
 227                         break;
 228                 case R_TILEGX_JUMPOFF_X1:
 229                         value -= (unsigned long) location;  /* pc-relative */
 230                         value = (long) value >> 3;     /* count by instrs */
 231                         if (!validate_jumpoff(value)) {
 232                                 pr_warning("module %s: Out of range jump to"
 233                                            " %#llx at %#llx (%p)\n", me->name,
 234                                            sym->st_value + rel[i].r_addend,
 235                                            rel[i].r_offset, location);
 236                                 return -ENOEXEC;
 237                         }
 238                         MUNGE(create_JumpOff_X1);
 239                         break;
 240 #endif
 241
 242 #undef MUNGE
 243
 244                 default:
 245                         pr_err("module %s: Unknown relocation: %d\n",
 246                                me->name, (int) ELF_R_TYPE(rel[i].r_info));
 247                         return -ENOEXEC;
 248                 }
 249         }
 250         return 0;
 251 }
 252
 253 int module_finalize(const Elf_Ehdr *hdr,
 254                     const Elf_Shdr *sechdrs,
 255                     struct module *me)
 256 {
 257         /* FIXME: perhaps remove the "writable" bit from the TLB? */
 258         return 0;
 259 }
 260
 261 void module_arch_cleanup(struct module *mod)
 262 {
 263 }