1 /* 2 * Kernel module support for Nios II. 3 * 4 * Copyright (C) 2004 Microtronix Datacom Ltd. 5 * Written by Wentao Xu <xuwentao@microtronix.com> 6 * Copyright (C) 2001, 2003 Rusty Russell 7 * 8 * This file is subject to the terms and conditions of the GNU General 9 * Public License. See the file COPYING in the main directory of this 10 * archive for more details. 11 */ 12 13 #include <linux/moduleloader.h> 14 #include <linux/elf.h> 15 #include <linux/mm.h> 16 #include <linux/vmalloc.h> 17 #include <linux/slab.h> 18 #include <linux/fs.h> 19 #include <linux/string.h> 20 #include <linux/kernel.h> 21 22 #include <asm/pgtable.h> 23 #include <asm/cacheflush.h> 24 25 /* 26 * Modules should NOT be allocated with kmalloc for (obvious) reasons. 27 * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach 28 * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns 29 * addresses in 0xc0000000) 30 */ 31 void *module_alloc(unsigned long size) 32 { 33 if (size == 0) 34 return NULL; 35 return kmalloc(size, GFP_KERNEL); 36 } 37 38 /* Free memory returned from module_alloc */ 39 void module_free(struct module *mod, void *module_region) 40 { 41 kfree(module_region); 42 } 43 44 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab, 45 unsigned int symindex, unsigned int relsec, 46 struct module *mod) 47 { 48 unsigned int i; 49 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; 50 51 pr_debug("Applying relocate section %u to %u\n", relsec, 52 sechdrs[relsec].sh_info); 53 54 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 55 /* This is where to make the change */ 56 uint32_t word; 57 uint32_t *loc 58 = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 59 + rela[i].r_offset); 60 /* This is the symbol it is referring to. Note that all 61 undefined symbols have been resolved. */ 62 Elf32_Sym *sym 63 = ((Elf32_Sym *)sechdrs[symindex].sh_addr 64 + ELF32_R_SYM(rela[i].r_info)); 65 uint32_t v = sym->st_value + rela[i].r_addend; 66 67 pr_debug("reltype %d 0x%x name:<%s>\n", 68 ELF32_R_TYPE(rela[i].r_info), 69 rela[i].r_offset, strtab + sym->st_name); 70 71 switch (ELF32_R_TYPE(rela[i].r_info)) { 72 case R_NIOS2_NONE: 73 break; 74 case R_NIOS2_BFD_RELOC_32: 75 *loc += v; 76 break; 77 case R_NIOS2_PCREL16: 78 v -= (uint32_t)loc + 4; 79 if ((int32_t)v > 0x7fff || 80 (int32_t)v < -(int32_t)0x8000) { 81 pr_err("module %s: relocation overflow\n", 82 mod->name); 83 return -ENOEXEC; 84 } 85 word = *loc; 86 *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) | 87 (word & 0x3f); 88 break; 89 case R_NIOS2_CALL26: 90 if (v & 3) { 91 pr_err("module %s: dangerous relocation\n", 92 mod->name); 93 return -ENOEXEC; 94 } 95 if ((v >> 28) != ((uint32_t)loc >> 28)) { 96 pr_err("module %s: relocation overflow\n", 97 mod->name); 98 return -ENOEXEC; 99 } 100 *loc = (*loc & 0x3f) | ((v >> 2) << 6); 101 break; 102 case R_NIOS2_HI16: 103 word = *loc; 104 *loc = ((((word >> 22) << 16) | 105 ((v >> 16) & 0xffff)) << 6) | (word & 0x3f); 106 break; 107 case R_NIOS2_LO16: 108 word = *loc; 109 *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) | 110 (word & 0x3f); 111 break; 112 case R_NIOS2_HIADJ16: 113 { 114 Elf32_Addr word2; 115 116 word = *loc; 117 word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff; 118 *loc = ((((word >> 22) << 16) | word2) << 6) | 119 (word & 0x3f); 120 } 121 break; 122 123 default: 124 pr_err("module %s: Unknown reloc: %u\n", 125 mod->name, ELF32_R_TYPE(rela[i].r_info)); 126 return -ENOEXEC; 127 } 128 } 129 130 return 0; 131 } 132 133 int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, 134 struct module *me) 135 { 136 flush_cache_all(); 137 return 0; 138 } 139