1 /*- 2 * Copyright (c) 2013 Dmitry Chagin 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_compat.h" 31 32 #if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32)) 33 #define __ELF_WORD_SIZE 32 34 #else 35 #define __ELF_WORD_SIZE 64 36 #endif 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/elf.h> 41 #include <sys/kernel.h> 42 #include <sys/lock.h> 43 #include <sys/rwlock.h> 44 #include <sys/queue.h> 45 #include <sys/sysent.h> 46 47 #include <vm/vm.h> 48 #include <vm/vm_param.h> 49 #include <vm/pmap.h> 50 #include <vm/vm_extern.h> 51 #include <vm/vm_kern.h> 52 #include <vm/vm_map.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_page.h> 55 #include <vm/vm_pager.h> 56 57 #include <compat/linux/linux_vdso.h> 58 59 SLIST_HEAD(, linux_vdso_sym) __elfN(linux_vdso_syms) = 60 SLIST_HEAD_INITIALIZER(__elfN(linux_vdso_syms)); 61 62 static int __elfN(symtabindex); 63 static int __elfN(symstrindex); 64 65 static void 66 __elfN(linux_vdso_lookup)(Elf_Ehdr *, struct linux_vdso_sym *); 67 68 69 void 70 __elfN(linux_vdso_sym_init)(struct linux_vdso_sym *s) 71 { 72 73 SLIST_INSERT_HEAD(&__elfN(linux_vdso_syms), s, sym); 74 } 75 76 vm_object_t 77 __elfN(linux_shared_page_init)(char **mapping) 78 { 79 vm_page_t m; 80 vm_object_t obj; 81 vm_offset_t addr; 82 83 obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE, 84 VM_PROT_DEFAULT, 0, NULL); 85 VM_OBJECT_WLOCK(obj); 86 m = vm_page_grab(obj, 0, VM_ALLOC_ZERO); 87 VM_OBJECT_WUNLOCK(obj); 88 vm_page_valid(m); 89 vm_page_xunbusy(m); 90 addr = kva_alloc(PAGE_SIZE); 91 pmap_qenter(addr, &m, 1); 92 *mapping = (char *)addr; 93 return (obj); 94 } 95 96 void 97 __elfN(linux_shared_page_fini)(vm_object_t obj) 98 { 99 100 vm_object_deallocate(obj); 101 } 102 103 void 104 __elfN(linux_vdso_fixup)(struct sysentvec *sv) 105 { 106 Elf_Ehdr *ehdr; 107 Elf_Shdr *shdr; 108 int i; 109 110 ehdr = (Elf_Ehdr *) sv->sv_sigcode; 111 112 if (!IS_ELF(*ehdr) || 113 ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 114 ehdr->e_ident[EI_DATA] != ELF_TARG_DATA || 115 ehdr->e_ident[EI_VERSION] != EV_CURRENT || 116 ehdr->e_shoff == 0 || 117 ehdr->e_shentsize != sizeof(Elf_Shdr)) 118 panic("Linux invalid vdso header.\n"); 119 120 if (ehdr->e_type != ET_DYN) 121 panic("Linux invalid vdso header.\n"); 122 123 shdr = (Elf_Shdr *) ((caddr_t)ehdr + ehdr->e_shoff); 124 125 __elfN(symtabindex) = -1; 126 __elfN(symstrindex) = -1; 127 for (i = 0; i < ehdr->e_shnum; i++) { 128 if (shdr[i].sh_size == 0) 129 continue; 130 if (shdr[i].sh_type == SHT_DYNSYM) { 131 __elfN(symtabindex) = i; 132 __elfN(symstrindex) = shdr[i].sh_link; 133 } 134 } 135 136 if (__elfN(symtabindex) == -1 || __elfN(symstrindex) == -1) 137 panic("Linux invalid vdso header.\n"); 138 139 ehdr->e_ident[EI_OSABI] = ELFOSABI_LINUX; 140 } 141 142 void 143 __elfN(linux_vdso_reloc)(struct sysentvec *sv) 144 { 145 struct linux_vdso_sym *lsym; 146 Elf_Ehdr *ehdr; 147 Elf_Phdr *phdr; 148 Elf_Shdr *shdr; 149 Elf_Dyn *dyn; 150 Elf_Sym *sym; 151 int i, j, symcnt; 152 153 ehdr = (Elf_Ehdr *) sv->sv_sigcode; 154 155 /* Adjust our so relative to the sigcode_base */ 156 if (sv->sv_shared_page_base != 0) { 157 ehdr->e_entry += sv->sv_shared_page_base; 158 phdr = (Elf_Phdr *)((caddr_t)ehdr + ehdr->e_phoff); 159 160 /* phdrs */ 161 for (i = 0; i < ehdr->e_phnum; i++) { 162 phdr[i].p_vaddr += sv->sv_shared_page_base; 163 if (phdr[i].p_type != PT_DYNAMIC) 164 continue; 165 dyn = (Elf_Dyn *)((caddr_t)ehdr + phdr[i].p_offset); 166 for(; dyn->d_tag != DT_NULL; dyn++) { 167 switch (dyn->d_tag) { 168 case DT_PLTGOT: 169 case DT_HASH: 170 case DT_STRTAB: 171 case DT_SYMTAB: 172 case DT_RELA: 173 case DT_INIT: 174 case DT_FINI: 175 case DT_REL: 176 case DT_DEBUG: 177 case DT_JMPREL: 178 case DT_VERSYM: 179 case DT_VERDEF: 180 case DT_VERNEED: 181 case DT_ADDRRNGLO ... DT_ADDRRNGHI: 182 dyn->d_un.d_ptr += sv->sv_shared_page_base; 183 break; 184 case DT_ENCODING ... DT_LOOS-1: 185 case DT_LOOS ... DT_HIOS: 186 if (dyn->d_tag >= DT_ENCODING && 187 (dyn->d_tag & 1) == 0) 188 dyn->d_un.d_ptr += sv->sv_shared_page_base; 189 break; 190 default: 191 break; 192 } 193 } 194 } 195 196 /* sections */ 197 shdr = (Elf_Shdr *)((caddr_t)ehdr + ehdr->e_shoff); 198 for(i = 0; i < ehdr->e_shnum; i++) { 199 if (!(shdr[i].sh_flags & SHF_ALLOC)) 200 continue; 201 shdr[i].sh_addr += sv->sv_shared_page_base; 202 if (shdr[i].sh_type != SHT_SYMTAB && 203 shdr[i].sh_type != SHT_DYNSYM) 204 continue; 205 206 sym = (Elf_Sym *)((caddr_t)ehdr + shdr[i].sh_offset); 207 symcnt = shdr[i].sh_size / sizeof(*sym); 208 209 for(j = 0; j < symcnt; j++, sym++) { 210 if (sym->st_shndx == SHN_UNDEF || 211 sym->st_shndx == SHN_ABS) 212 continue; 213 sym->st_value += sv->sv_shared_page_base; 214 } 215 } 216 } 217 218 SLIST_FOREACH(lsym, &__elfN(linux_vdso_syms), sym) 219 __elfN(linux_vdso_lookup)(ehdr, lsym); 220 } 221 222 static void 223 __elfN(linux_vdso_lookup)(Elf_Ehdr *ehdr, struct linux_vdso_sym *vsym) 224 { 225 vm_offset_t strtab, symname; 226 uint32_t symcnt; 227 Elf_Shdr *shdr; 228 int i; 229 230 shdr = (Elf_Shdr *) ((caddr_t)ehdr + ehdr->e_shoff); 231 232 strtab = (vm_offset_t)((caddr_t)ehdr + 233 shdr[__elfN(symstrindex)].sh_offset); 234 Elf_Sym *sym = (Elf_Sym *)((caddr_t)ehdr + 235 shdr[__elfN(symtabindex)].sh_offset); 236 symcnt = shdr[__elfN(symtabindex)].sh_size / sizeof(*sym); 237 238 for (i = 0; i < symcnt; ++i, ++sym) { 239 symname = strtab + sym->st_name; 240 if (strncmp(vsym->symname, (char *)symname, vsym->size) == 0) { 241 *vsym->ptr = (uintptr_t)sym->st_value; 242 break; 243 } 244 } 245 } 246