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