1ed981856SPaul Mackerras /* Kernel module help for PPC. 2ed981856SPaul Mackerras Copyright (C) 2001 Rusty Russell. 3ed981856SPaul Mackerras 4ed981856SPaul Mackerras This program is free software; you can redistribute it and/or modify 5ed981856SPaul Mackerras it under the terms of the GNU General Public License as published by 6ed981856SPaul Mackerras the Free Software Foundation; either version 2 of the License, or 7ed981856SPaul Mackerras (at your option) any later version. 8ed981856SPaul Mackerras 9ed981856SPaul Mackerras This program is distributed in the hope that it will be useful, 10ed981856SPaul Mackerras but WITHOUT ANY WARRANTY; without even the implied warranty of 11ed981856SPaul Mackerras MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12ed981856SPaul Mackerras GNU General Public License for more details. 13ed981856SPaul Mackerras 14ed981856SPaul Mackerras You should have received a copy of the GNU General Public License 15ed981856SPaul Mackerras along with this program; if not, write to the Free Software 16ed981856SPaul Mackerras Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17ed981856SPaul Mackerras */ 18ed981856SPaul Mackerras #include <linux/module.h> 19ed981856SPaul Mackerras #include <linux/moduleloader.h> 20ed981856SPaul Mackerras #include <linux/elf.h> 21ed981856SPaul Mackerras #include <linux/vmalloc.h> 22ed981856SPaul Mackerras #include <linux/fs.h> 23ed981856SPaul Mackerras #include <linux/string.h> 24ed981856SPaul Mackerras #include <linux/kernel.h> 25ed981856SPaul Mackerras #include <linux/cache.h> 2673c9ceabSJeremy Fitzhardinge #include <linux/bug.h> 27ed981856SPaul Mackerras 2821c4ff80SBenjamin Herrenschmidt #include "setup.h" 2921c4ff80SBenjamin Herrenschmidt 30ed981856SPaul Mackerras #if 0 31ed981856SPaul Mackerras #define DEBUGP printk 32ed981856SPaul Mackerras #else 33ed981856SPaul Mackerras #define DEBUGP(fmt , ...) 34ed981856SPaul Mackerras #endif 35ed981856SPaul Mackerras 36ed981856SPaul Mackerras LIST_HEAD(module_bug_list); 37ed981856SPaul Mackerras 38ed981856SPaul Mackerras void *module_alloc(unsigned long size) 39ed981856SPaul Mackerras { 40ed981856SPaul Mackerras if (size == 0) 41ed981856SPaul Mackerras return NULL; 42ed981856SPaul Mackerras return vmalloc(size); 43ed981856SPaul Mackerras } 44ed981856SPaul Mackerras 45ed981856SPaul Mackerras /* Free memory returned from module_alloc */ 46ed981856SPaul Mackerras void module_free(struct module *mod, void *module_region) 47ed981856SPaul Mackerras { 48ed981856SPaul Mackerras vfree(module_region); 49ed981856SPaul Mackerras /* FIXME: If module_region == mod->init_region, trim exception 50ed981856SPaul Mackerras table entries. */ 51ed981856SPaul Mackerras } 52ed981856SPaul Mackerras 53ed981856SPaul Mackerras /* Count how many different relocations (different symbol, different 54ed981856SPaul Mackerras addend) */ 55ed981856SPaul Mackerras static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num) 56ed981856SPaul Mackerras { 57ed981856SPaul Mackerras unsigned int i, j, ret = 0; 58ed981856SPaul Mackerras 59ed981856SPaul Mackerras /* Sure, this is order(n^2), but it's usually short, and not 60ed981856SPaul Mackerras time critical */ 61ed981856SPaul Mackerras for (i = 0; i < num; i++) { 62ed981856SPaul Mackerras for (j = 0; j < i; j++) { 63ed981856SPaul Mackerras /* If this addend appeared before, it's 64ed981856SPaul Mackerras already been counted */ 65ed981856SPaul Mackerras if (ELF32_R_SYM(rela[i].r_info) 66ed981856SPaul Mackerras == ELF32_R_SYM(rela[j].r_info) 67ed981856SPaul Mackerras && rela[i].r_addend == rela[j].r_addend) 68ed981856SPaul Mackerras break; 69ed981856SPaul Mackerras } 70ed981856SPaul Mackerras if (j == i) ret++; 71ed981856SPaul Mackerras } 72ed981856SPaul Mackerras return ret; 73ed981856SPaul Mackerras } 74ed981856SPaul Mackerras 75ed981856SPaul Mackerras /* Get the potential trampolines size required of the init and 76ed981856SPaul Mackerras non-init sections */ 77ed981856SPaul Mackerras static unsigned long get_plt_size(const Elf32_Ehdr *hdr, 78ed981856SPaul Mackerras const Elf32_Shdr *sechdrs, 79ed981856SPaul Mackerras const char *secstrings, 80ed981856SPaul Mackerras int is_init) 81ed981856SPaul Mackerras { 82ed981856SPaul Mackerras unsigned long ret = 0; 83ed981856SPaul Mackerras unsigned i; 84ed981856SPaul Mackerras 85ed981856SPaul Mackerras /* Everything marked ALLOC (this includes the exported 86ed981856SPaul Mackerras symbols) */ 87ed981856SPaul Mackerras for (i = 1; i < hdr->e_shnum; i++) { 88ed981856SPaul Mackerras /* If it's called *.init*, and we're not init, we're 89ed981856SPaul Mackerras not interested */ 90ed981856SPaul Mackerras if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0) 91ed981856SPaul Mackerras != is_init) 92ed981856SPaul Mackerras continue; 93ed981856SPaul Mackerras 94ed981856SPaul Mackerras /* We don't want to look at debug sections. */ 95ed981856SPaul Mackerras if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0) 96ed981856SPaul Mackerras continue; 97ed981856SPaul Mackerras 98ed981856SPaul Mackerras if (sechdrs[i].sh_type == SHT_RELA) { 99ed981856SPaul Mackerras DEBUGP("Found relocations in section %u\n", i); 100ed981856SPaul Mackerras DEBUGP("Ptr: %p. Number: %u\n", 101ed981856SPaul Mackerras (void *)hdr + sechdrs[i].sh_offset, 102ed981856SPaul Mackerras sechdrs[i].sh_size / sizeof(Elf32_Rela)); 103ed981856SPaul Mackerras ret += count_relocs((void *)hdr 104ed981856SPaul Mackerras + sechdrs[i].sh_offset, 105ed981856SPaul Mackerras sechdrs[i].sh_size 106ed981856SPaul Mackerras / sizeof(Elf32_Rela)) 107ed981856SPaul Mackerras * sizeof(struct ppc_plt_entry); 108ed981856SPaul Mackerras } 109ed981856SPaul Mackerras } 110ed981856SPaul Mackerras 111ed981856SPaul Mackerras return ret; 112ed981856SPaul Mackerras } 113ed981856SPaul Mackerras 114ed981856SPaul Mackerras int module_frob_arch_sections(Elf32_Ehdr *hdr, 115ed981856SPaul Mackerras Elf32_Shdr *sechdrs, 116ed981856SPaul Mackerras char *secstrings, 117ed981856SPaul Mackerras struct module *me) 118ed981856SPaul Mackerras { 119ed981856SPaul Mackerras unsigned int i; 120ed981856SPaul Mackerras 121ed981856SPaul Mackerras /* Find .plt and .init.plt sections */ 122ed981856SPaul Mackerras for (i = 0; i < hdr->e_shnum; i++) { 123ed981856SPaul Mackerras if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0) 124ed981856SPaul Mackerras me->arch.init_plt_section = i; 125ed981856SPaul Mackerras else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) 126ed981856SPaul Mackerras me->arch.core_plt_section = i; 127ed981856SPaul Mackerras } 128ed981856SPaul Mackerras if (!me->arch.core_plt_section || !me->arch.init_plt_section) { 129ed981856SPaul Mackerras printk("Module doesn't contain .plt or .init.plt sections.\n"); 130ed981856SPaul Mackerras return -ENOEXEC; 131ed981856SPaul Mackerras } 132ed981856SPaul Mackerras 133ed981856SPaul Mackerras /* Override their sizes */ 134ed981856SPaul Mackerras sechdrs[me->arch.core_plt_section].sh_size 135ed981856SPaul Mackerras = get_plt_size(hdr, sechdrs, secstrings, 0); 136ed981856SPaul Mackerras sechdrs[me->arch.init_plt_section].sh_size 137ed981856SPaul Mackerras = get_plt_size(hdr, sechdrs, secstrings, 1); 138ed981856SPaul Mackerras return 0; 139ed981856SPaul Mackerras } 140ed981856SPaul Mackerras 141ed981856SPaul Mackerras int apply_relocate(Elf32_Shdr *sechdrs, 142ed981856SPaul Mackerras const char *strtab, 143ed981856SPaul Mackerras unsigned int symindex, 144ed981856SPaul Mackerras unsigned int relsec, 145ed981856SPaul Mackerras struct module *module) 146ed981856SPaul Mackerras { 147ed981856SPaul Mackerras printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", 148ed981856SPaul Mackerras module->name); 149ed981856SPaul Mackerras return -ENOEXEC; 150ed981856SPaul Mackerras } 151ed981856SPaul Mackerras 152ed981856SPaul Mackerras static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val) 153ed981856SPaul Mackerras { 154ed981856SPaul Mackerras if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16) 155ed981856SPaul Mackerras && entry->jump[1] == 0x396b0000 + (val & 0xffff)) 156ed981856SPaul Mackerras return 1; 157ed981856SPaul Mackerras return 0; 158ed981856SPaul Mackerras } 159ed981856SPaul Mackerras 160ed981856SPaul Mackerras /* Set up a trampoline in the PLT to bounce us to the distant function */ 161ed981856SPaul Mackerras static uint32_t do_plt_call(void *location, 162ed981856SPaul Mackerras Elf32_Addr val, 163ed981856SPaul Mackerras Elf32_Shdr *sechdrs, 164ed981856SPaul Mackerras struct module *mod) 165ed981856SPaul Mackerras { 166ed981856SPaul Mackerras struct ppc_plt_entry *entry; 167ed981856SPaul Mackerras 168ed981856SPaul Mackerras DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location); 169ed981856SPaul Mackerras /* Init, or core PLT? */ 170ed981856SPaul Mackerras if (location >= mod->module_core 171ed981856SPaul Mackerras && location < mod->module_core + mod->core_size) 172ed981856SPaul Mackerras entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr; 173ed981856SPaul Mackerras else 174ed981856SPaul Mackerras entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr; 175ed981856SPaul Mackerras 176ed981856SPaul Mackerras /* Find this entry, or if that fails, the next avail. entry */ 177ed981856SPaul Mackerras while (entry->jump[0]) { 178ed981856SPaul Mackerras if (entry_matches(entry, val)) return (uint32_t)entry; 179ed981856SPaul Mackerras entry++; 180ed981856SPaul Mackerras } 181ed981856SPaul Mackerras 182ed981856SPaul Mackerras /* Stolen from Paul Mackerras as well... */ 183ed981856SPaul Mackerras entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */ 184ed981856SPaul Mackerras entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/ 185ed981856SPaul Mackerras entry->jump[2] = 0x7d6903a6; /* mtctr r11 */ 186ed981856SPaul Mackerras entry->jump[3] = 0x4e800420; /* bctr */ 187ed981856SPaul Mackerras 188ed981856SPaul Mackerras DEBUGP("Initialized plt for 0x%x at %p\n", val, entry); 189ed981856SPaul Mackerras return (uint32_t)entry; 190ed981856SPaul Mackerras } 191ed981856SPaul Mackerras 192ed981856SPaul Mackerras int apply_relocate_add(Elf32_Shdr *sechdrs, 193ed981856SPaul Mackerras const char *strtab, 194ed981856SPaul Mackerras unsigned int symindex, 195ed981856SPaul Mackerras unsigned int relsec, 196ed981856SPaul Mackerras struct module *module) 197ed981856SPaul Mackerras { 198ed981856SPaul Mackerras unsigned int i; 199ed981856SPaul Mackerras Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; 200ed981856SPaul Mackerras Elf32_Sym *sym; 201ed981856SPaul Mackerras uint32_t *location; 202ed981856SPaul Mackerras uint32_t value; 203ed981856SPaul Mackerras 204ed981856SPaul Mackerras DEBUGP("Applying ADD relocate section %u to %u\n", relsec, 205ed981856SPaul Mackerras sechdrs[relsec].sh_info); 206ed981856SPaul Mackerras for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { 207ed981856SPaul Mackerras /* This is where to make the change */ 208ed981856SPaul Mackerras location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 209ed981856SPaul Mackerras + rela[i].r_offset; 210ed981856SPaul Mackerras /* This is the symbol it is referring to. Note that all 211ed981856SPaul Mackerras undefined symbols have been resolved. */ 212ed981856SPaul Mackerras sym = (Elf32_Sym *)sechdrs[symindex].sh_addr 213ed981856SPaul Mackerras + ELF32_R_SYM(rela[i].r_info); 214ed981856SPaul Mackerras /* `Everything is relative'. */ 215ed981856SPaul Mackerras value = sym->st_value + rela[i].r_addend; 216ed981856SPaul Mackerras 217ed981856SPaul Mackerras switch (ELF32_R_TYPE(rela[i].r_info)) { 218ed981856SPaul Mackerras case R_PPC_ADDR32: 219ed981856SPaul Mackerras /* Simply set it */ 220ed981856SPaul Mackerras *(uint32_t *)location = value; 221ed981856SPaul Mackerras break; 222ed981856SPaul Mackerras 223ed981856SPaul Mackerras case R_PPC_ADDR16_LO: 224ed981856SPaul Mackerras /* Low half of the symbol */ 225ed981856SPaul Mackerras *(uint16_t *)location = value; 226ed981856SPaul Mackerras break; 227ed981856SPaul Mackerras 228ed981856SPaul Mackerras case R_PPC_ADDR16_HA: 229ed981856SPaul Mackerras /* Sign-adjusted lower 16 bits: PPC ELF ABI says: 230ed981856SPaul Mackerras (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF. 231ed981856SPaul Mackerras This is the same, only sane. 232ed981856SPaul Mackerras */ 233ed981856SPaul Mackerras *(uint16_t *)location = (value + 0x8000) >> 16; 234ed981856SPaul Mackerras break; 235ed981856SPaul Mackerras 236ed981856SPaul Mackerras case R_PPC_REL24: 237ed981856SPaul Mackerras if ((int)(value - (uint32_t)location) < -0x02000000 238ed981856SPaul Mackerras || (int)(value - (uint32_t)location) >= 0x02000000) 239ed981856SPaul Mackerras value = do_plt_call(location, value, 240ed981856SPaul Mackerras sechdrs, module); 241ed981856SPaul Mackerras 242ed981856SPaul Mackerras /* Only replace bits 2 through 26 */ 243ed981856SPaul Mackerras DEBUGP("REL24 value = %08X. location = %08X\n", 244ed981856SPaul Mackerras value, (uint32_t)location); 245ed981856SPaul Mackerras DEBUGP("Location before: %08X.\n", 246ed981856SPaul Mackerras *(uint32_t *)location); 247ed981856SPaul Mackerras *(uint32_t *)location 248ed981856SPaul Mackerras = (*(uint32_t *)location & ~0x03fffffc) 249ed981856SPaul Mackerras | ((value - (uint32_t)location) 250ed981856SPaul Mackerras & 0x03fffffc); 251ed981856SPaul Mackerras DEBUGP("Location after: %08X.\n", 252ed981856SPaul Mackerras *(uint32_t *)location); 253ed981856SPaul Mackerras DEBUGP("ie. jump to %08X+%08X = %08X\n", 254ed981856SPaul Mackerras *(uint32_t *)location & 0x03fffffc, 255ed981856SPaul Mackerras (uint32_t)location, 256ed981856SPaul Mackerras (*(uint32_t *)location & 0x03fffffc) 257ed981856SPaul Mackerras + (uint32_t)location); 258ed981856SPaul Mackerras break; 259ed981856SPaul Mackerras 260ed981856SPaul Mackerras case R_PPC_REL32: 261ed981856SPaul Mackerras /* 32-bit relative jump. */ 262ed981856SPaul Mackerras *(uint32_t *)location = value - (uint32_t)location; 263ed981856SPaul Mackerras break; 264ed981856SPaul Mackerras 265ed981856SPaul Mackerras default: 266ed981856SPaul Mackerras printk("%s: unknown ADD relocation: %u\n", 267ed981856SPaul Mackerras module->name, 268ed981856SPaul Mackerras ELF32_R_TYPE(rela[i].r_info)); 269ed981856SPaul Mackerras return -ENOEXEC; 270ed981856SPaul Mackerras } 271ed981856SPaul Mackerras } 272ed981856SPaul Mackerras return 0; 273ed981856SPaul Mackerras } 274ed981856SPaul Mackerras 27521c4ff80SBenjamin Herrenschmidt static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, 27621c4ff80SBenjamin Herrenschmidt const Elf_Shdr *sechdrs, 27721c4ff80SBenjamin Herrenschmidt const char *name) 27821c4ff80SBenjamin Herrenschmidt { 27921c4ff80SBenjamin Herrenschmidt char *secstrings; 28021c4ff80SBenjamin Herrenschmidt unsigned int i; 28121c4ff80SBenjamin Herrenschmidt 28221c4ff80SBenjamin Herrenschmidt secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 28321c4ff80SBenjamin Herrenschmidt for (i = 1; i < hdr->e_shnum; i++) 28421c4ff80SBenjamin Herrenschmidt if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0) 28521c4ff80SBenjamin Herrenschmidt return &sechdrs[i]; 28621c4ff80SBenjamin Herrenschmidt return NULL; 28721c4ff80SBenjamin Herrenschmidt } 28821c4ff80SBenjamin Herrenschmidt 289ed981856SPaul Mackerras int module_finalize(const Elf_Ehdr *hdr, 290ed981856SPaul Mackerras const Elf_Shdr *sechdrs, 291ed981856SPaul Mackerras struct module *me) 292ed981856SPaul Mackerras { 29321c4ff80SBenjamin Herrenschmidt const Elf_Shdr *sect; 29473c9ceabSJeremy Fitzhardinge int err; 295ed981856SPaul Mackerras 29673c9ceabSJeremy Fitzhardinge err = module_bug_finalize(hdr, sechdrs, me); 29773c9ceabSJeremy Fitzhardinge if (err) /* never true, currently */ 29873c9ceabSJeremy Fitzhardinge return err; 299ed981856SPaul Mackerras 30021c4ff80SBenjamin Herrenschmidt /* Apply feature fixups */ 30121c4ff80SBenjamin Herrenschmidt sect = find_section(hdr, sechdrs, "__ftr_fixup"); 30221c4ff80SBenjamin Herrenschmidt if (sect != NULL) 30321c4ff80SBenjamin Herrenschmidt do_feature_fixups(cur_cpu_spec->cpu_features, 30421c4ff80SBenjamin Herrenschmidt (void *)sect->sh_addr, 30521c4ff80SBenjamin Herrenschmidt (void *)sect->sh_addr + sect->sh_size); 30621c4ff80SBenjamin Herrenschmidt 307ed981856SPaul Mackerras return 0; 308ed981856SPaul Mackerras } 309ed981856SPaul Mackerras 310ed981856SPaul Mackerras void module_arch_cleanup(struct module *mod) 311ed981856SPaul Mackerras { 31273c9ceabSJeremy Fitzhardinge module_bug_cleanup(mod); 313ed981856SPaul Mackerras } 314ed981856SPaul Mackerras 315ed981856SPaul Mackerras struct bug_entry *module_find_bug(unsigned long bugaddr) 316ed981856SPaul Mackerras { 317ed981856SPaul Mackerras struct mod_arch_specific *mod; 318ed981856SPaul Mackerras unsigned int i; 319ed981856SPaul Mackerras struct bug_entry *bug; 320ed981856SPaul Mackerras 321ed981856SPaul Mackerras list_for_each_entry(mod, &module_bug_list, bug_list) { 322ed981856SPaul Mackerras bug = mod->bug_table; 323ed981856SPaul Mackerras for (i = 0; i < mod->num_bugs; ++i, ++bug) 324ed981856SPaul Mackerras if (bugaddr == bug->bug_addr) 325ed981856SPaul Mackerras return bug; 326ed981856SPaul Mackerras } 327ed981856SPaul Mackerras return NULL; 328ed981856SPaul Mackerras } 329