| /* Kernel module help for PPC. |
| Copyright (C) 2001 Rusty Russell. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| #include <linux/module.h> |
| #include <linux/moduleloader.h> |
| #include <linux/elf.h> |
| #include <linux/vmalloc.h> |
| #include <linux/fs.h> |
| #include <linux/string.h> |
| #include <linux/kernel.h> |
| #include <linux/cache.h> |
| #include <linux/bug.h> |
| #include <linux/sort.h> |
| |
| #include "setup.h" |
| |
| #if 0 |
| #define DEBUGP printk |
| #else |
| #define DEBUGP(fmt , ...) |
| #endif |
| |
| LIST_HEAD(module_bug_list); |
| |
| void *module_alloc(unsigned long size) |
| { |
| if (size == 0) |
| return NULL; |
| return vmalloc(size); |
| } |
| |
| /* Free memory returned from module_alloc */ |
| void module_free(struct module *mod, void *module_region) |
| { |
| vfree(module_region); |
| /* FIXME: If module_region == mod->init_region, trim exception |
| table entries. */ |
| } |
| |
| /* Count how many different relocations (different symbol, different |
| addend) */ |
| static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num) |
| { |
| unsigned int i, r_info, r_addend, _count_relocs; |
| |
| _count_relocs = 0; |
| r_info = 0; |
| r_addend = 0; |
| for (i = 0; i < num; i++) |
| /* Only count 24-bit relocs, others don't need stubs */ |
| if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 && |
| (r_info != ELF32_R_SYM(rela[i].r_info) || |
| r_addend != rela[i].r_addend)) { |
| _count_relocs++; |
| r_info = ELF32_R_SYM(rela[i].r_info); |
| r_addend = rela[i].r_addend; |
| } |
| |
| return _count_relocs; |
| } |
| |
| static int relacmp(const void *_x, const void *_y) |
| { |
| const Elf32_Rela *x, *y; |
| |
| y = (Elf32_Rela *)_x; |
| x = (Elf32_Rela *)_y; |
| |
| /* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to |
| * make the comparison cheaper/faster. It won't affect the sorting or |
| * the counting algorithms' performance |
| */ |
| if (x->r_info < y->r_info) |
| return -1; |
| else if (x->r_info > y->r_info) |
| return 1; |
| else if (x->r_addend < y->r_addend) |
| return -1; |
| else if (x->r_addend > y->r_addend) |
| return 1; |
| else |
| return 0; |
| } |
| |
| static void relaswap(void *_x, void *_y, int size) |
| { |
| uint32_t *x, *y, tmp; |
| int i; |
| |
| y = (uint32_t *)_x; |
| x = (uint32_t *)_y; |
| |
| for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) { |
| tmp = x[i]; |
| x[i] = y[i]; |
| y[i] = tmp; |
| } |
| } |
| |
| /* Get the potential trampolines size required of the init and |
| non-init sections */ |
| static unsigned long get_plt_size(const Elf32_Ehdr *hdr, |
| const Elf32_Shdr *sechdrs, |
| const char *secstrings, |
| int is_init) |
| { |
| unsigned long ret = 0; |
| unsigned i; |
| |
| /* Everything marked ALLOC (this includes the exported |
| symbols) */ |
| for (i = 1; i < hdr->e_shnum; i++) { |
| /* If it's called *.init*, and we're not init, we're |
| not interested */ |
| if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0) |
| != is_init) |
| continue; |
| |
| /* We don't want to look at debug sections. */ |
| if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0) |
| continue; |
| |
| if (sechdrs[i].sh_type == SHT_RELA) { |
| DEBUGP("Found relocations in section %u\n", i); |
| DEBUGP("Ptr: %p. Number: %u\n", |
| (void *)hdr + sechdrs[i].sh_offset, |
| sechdrs[i].sh_size / sizeof(Elf32_Rela)); |
| |
| /* Sort the relocation information based on a symbol and |
| * addend key. This is a stable O(n*log n) complexity |
| * alogrithm but it will reduce the complexity of |
| * count_relocs() to linear complexity O(n) |
| */ |
| sort((void *)hdr + sechdrs[i].sh_offset, |
| sechdrs[i].sh_size / sizeof(Elf32_Rela), |
| sizeof(Elf32_Rela), relacmp, relaswap); |
| |
| ret += count_relocs((void *)hdr |
| + sechdrs[i].sh_offset, |
| sechdrs[i].sh_size |
| / sizeof(Elf32_Rela)) |
| * sizeof(struct ppc_plt_entry); |
| } |
| } |
| |
| return ret; |
| } |
| |
| int module_frob_arch_sections(Elf32_Ehdr *hdr, |
| Elf32_Shdr *sechdrs, |
| char *secstrings, |
| struct module *me) |
| { |
| unsigned int i; |
| |
| /* Find .plt and .init.plt sections */ |
| for (i = 0; i < hdr->e_shnum; i++) { |
| if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0) |
| me->arch.init_plt_section = i; |
| else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) |
| me->arch.core_plt_section = i; |
| } |
| if (!me->arch.core_plt_section || !me->arch.init_plt_section) { |
| printk("Module doesn't contain .plt or .init.plt sections.\n"); |
| return -ENOEXEC; |
| } |
| |
| /* Override their sizes */ |
| sechdrs[me->arch.core_plt_section].sh_size |
| = get_plt_size(hdr, sechdrs, secstrings, 0); |
| sechdrs[me->arch.init_plt_section].sh_size |
| = get_plt_size(hdr, sechdrs, secstrings, 1); |
| return 0; |
| } |
| |
| int apply_relocate(Elf32_Shdr *sechdrs, |
| const char *strtab, |
| unsigned int symindex, |
| unsigned int relsec, |
| struct module *module) |
| { |
| printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", |
| module->name); |
| return -ENOEXEC; |
| } |
| |
| static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val) |
| { |
| if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16) |
| && entry->jump[1] == 0x396b0000 + (val & 0xffff)) |
| return 1; |
| return 0; |
| } |
| |
| /* Set up a trampoline in the PLT to bounce us to the distant function */ |
| static uint32_t do_plt_call(void *location, |
| Elf32_Addr val, |
| Elf32_Shdr *sechdrs, |
| struct module *mod) |
| { |
| struct ppc_plt_entry *entry; |
| |
| DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location); |
| /* Init, or core PLT? */ |
| if (location >= mod->module_core |
| && location < mod->module_core + mod->core_size) |
| entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr; |
| else |
| entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr; |
| |
| /* Find this entry, or if that fails, the next avail. entry */ |
| while (entry->jump[0]) { |
| if (entry_matches(entry, val)) return (uint32_t)entry; |
| entry++; |
| } |
| |
| /* Stolen from Paul Mackerras as well... */ |
| entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */ |
| entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/ |
| entry->jump[2] = 0x7d6903a6; /* mtctr r11 */ |
| entry->jump[3] = 0x4e800420; /* bctr */ |
| |
| DEBUGP("Initialized plt for 0x%x at %p\n", val, entry); |
| return (uint32_t)entry; |
| } |
| |
| int apply_relocate_add(Elf32_Shdr *sechdrs, |
| const char *strtab, |
| unsigned int symindex, |
| unsigned int relsec, |
| struct module *module) |
| { |
| unsigned int i; |
| Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; |
| Elf32_Sym *sym; |
| uint32_t *location; |
| uint32_t value; |
| |
| DEBUGP("Applying ADD relocate section %u to %u\n", relsec, |
| sechdrs[relsec].sh_info); |
| for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { |
| /* This is where to make the change */ |
| location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr |
| + rela[i].r_offset; |
| /* This is the symbol it is referring to. Note that all |
| undefined symbols have been resolved. */ |
| sym = (Elf32_Sym *)sechdrs[symindex].sh_addr |
| + ELF32_R_SYM(rela[i].r_info); |
| /* `Everything is relative'. */ |
| value = sym->st_value + rela[i].r_addend; |
| |
| switch (ELF32_R_TYPE(rela[i].r_info)) { |
| case R_PPC_ADDR32: |
| /* Simply set it */ |
| *(uint32_t *)location = value; |
| break; |
| |
| case R_PPC_ADDR16_LO: |
| /* Low half of the symbol */ |
| *(uint16_t *)location = value; |
| break; |
| |
| case R_PPC_ADDR16_HI: |
| /* Higher half of the symbol */ |
| *(uint16_t *)location = (value >> 16); |
| break; |
| |
| case R_PPC_ADDR16_HA: |
| /* Sign-adjusted lower 16 bits: PPC ELF ABI says: |
| (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF. |
| This is the same, only sane. |
| */ |
| *(uint16_t *)location = (value + 0x8000) >> 16; |
| break; |
| |
| case R_PPC_REL24: |
| if ((int)(value - (uint32_t)location) < -0x02000000 |
| || (int)(value - (uint32_t)location) >= 0x02000000) |
| value = do_plt_call(location, value, |
| sechdrs, module); |
| |
| /* Only replace bits 2 through 26 */ |
| DEBUGP("REL24 value = %08X. location = %08X\n", |
| value, (uint32_t)location); |
| DEBUGP("Location before: %08X.\n", |
| *(uint32_t *)location); |
| *(uint32_t *)location |
| = (*(uint32_t *)location & ~0x03fffffc) |
| | ((value - (uint32_t)location) |
| & 0x03fffffc); |
| DEBUGP("Location after: %08X.\n", |
| *(uint32_t *)location); |
| DEBUGP("ie. jump to %08X+%08X = %08X\n", |
| *(uint32_t *)location & 0x03fffffc, |
| (uint32_t)location, |
| (*(uint32_t *)location & 0x03fffffc) |
| + (uint32_t)location); |
| break; |
| |
| case R_PPC_REL32: |
| /* 32-bit relative jump. */ |
| *(uint32_t *)location = value - (uint32_t)location; |
| break; |
| |
| default: |
| printk("%s: unknown ADD relocation: %u\n", |
| module->name, |
| ELF32_R_TYPE(rela[i].r_info)); |
| return -ENOEXEC; |
| } |
| } |
| return 0; |
| } |
| |
| static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, |
| const Elf_Shdr *sechdrs, |
| const char *name) |
| { |
| char *secstrings; |
| unsigned int i; |
| |
| secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; |
| for (i = 1; i < hdr->e_shnum; i++) |
| if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0) |
| return &sechdrs[i]; |
| return NULL; |
| } |
| |
| int module_finalize(const Elf_Ehdr *hdr, |
| const Elf_Shdr *sechdrs, |
| struct module *me) |
| { |
| const Elf_Shdr *sect; |
| int err; |
| |
| err = module_bug_finalize(hdr, sechdrs, me); |
| if (err) /* never true, currently */ |
| return err; |
| |
| /* Apply feature fixups */ |
| sect = find_section(hdr, sechdrs, "__ftr_fixup"); |
| if (sect != NULL) |
| do_feature_fixups(cur_cpu_spec->cpu_features, |
| (void *)sect->sh_addr, |
| (void *)sect->sh_addr + sect->sh_size); |
| |
| return 0; |
| } |
| |
| void module_arch_cleanup(struct module *mod) |
| { |
| module_bug_cleanup(mod); |
| } |
| |
| struct bug_entry *module_find_bug(unsigned long bugaddr) |
| { |
| struct mod_arch_specific *mod; |
| unsigned int i; |
| struct bug_entry *bug; |
| |
| list_for_each_entry(mod, &module_bug_list, bug_list) { |
| bug = mod->bug_table; |
| for (i = 0; i < mod->num_bugs; ++i, ++bug) |
| if (bugaddr == bug->bug_addr) |
| return bug; |
| } |
| return NULL; |
| } |