LXR linux/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 */
  37void *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 */
  76void 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 */
  95static 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 */
 108static 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
 121int 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}
 232