lib/elf.c

   1 // SPDX-License-Identifier: BSD-2-Clause
   2 /*
   3    Copyright (c) 2001 William L. Pitts
   4 */
   5
   6 #include <command.h>
   7 #include <cpu_func.h>
   8 #include <elf.h>
   9 #include <env.h>
  10 #include <errno.h>
  11 #include <net.h>
  12 #include <vxworks.h>
  13 #ifdef CONFIG_X86
  14 #include <vesa.h>
  15 #include <asm/e820.h>
  16 #include <linux/linkage.h>
  17 #endif
  18
  19 /**
  20  * bootelf_exec() - start the ELF image execution.
  21  *
  22  * @entry: address of entry point of ELF.
  23  *
  24  * May by used to allow ports to override the default behavior.
  25  */
  26 unsigned long bootelf_exec(ulong (*entry)(int, char * const[]),
  27                            int argc, char *const argv[])
  28 {
  29         return entry(argc, argv);
  30 }
  31
  32 /**
  33  * bootelf() - Boot ELF from memory.
  34  *
  35  * @addr:  Loading address of ELF in memory.
  36  * @flags: Bits like ELF_PHDR to control boot details.
  37  * @argc: May be used to pass command line arguments (maybe unused).
  38  *        Necessary for backward compatibility with the CLI command.
  39  *        If unused, must be 0.
  40  * @argv: see @argc. If unused, must be NULL.
  41  * Return: Number returned by ELF application.
  42  *
  43  * Sets errno = ENOEXEC if the ELF image is not valid.
  44  */
  45 unsigned long bootelf(unsigned long addr, Bootelf_flags flags,
  46                       int argc, char *const argv[])
  47 {
  48         unsigned long entry_addr;
  49         char *args[] = {"", NULL};
  50
  51         errno = 0;
  52
  53         if (!valid_elf_image(addr)) {
  54                 errno = ENOEXEC;
  55                 return 1;
  56         }
  57
  58         entry_addr = flags.phdr ? load_elf_image_phdr(addr)
  59                                             : load_elf_image_shdr(addr);
  60
  61         if (!flags.autostart)
  62                 return 0;
  63
  64         if (!argc && !argv) {
  65                 argc = 1;
  66                 argv = args;
  67         }
  68
  69         return bootelf_exec((void *)entry_addr, argc, argv);
  70 }
  71
  72 /*
  73  * A very simple ELF64 loader, assumes the image is valid, returns the
  74  * entry point address.
  75  *
  76  * Note if U-Boot is 32-bit, the loader assumes the to segment's
  77  * physical address and size is within the lower 32-bit address space.
  78  */
  79 unsigned long load_elf64_image_phdr(unsigned long addr)
  80 {
  81         Elf64_Ehdr *ehdr; /* Elf header structure pointer */
  82         Elf64_Phdr *phdr; /* Program header structure pointer */
  83         int i;
  84
  85         ehdr = (Elf64_Ehdr *)addr;
  86         phdr = (Elf64_Phdr *)(addr + (ulong)ehdr->e_phoff);
  87
  88         /* Load each program header */
  89         for (i = 0; i < ehdr->e_phnum; ++i, ++phdr) {
  90                 void *dst = (void *)(ulong)phdr->p_paddr;
  91                 void *src = (void *)addr + phdr->p_offset;
  92
  93                 /* Only load PT_LOAD program header */
  94                 if (phdr->p_type != PT_LOAD)
  95                         continue;
  96
  97                 debug("Loading phdr %i to 0x%p (%lu bytes)\n",
  98                       i, dst, (ulong)phdr->p_filesz);
  99                 if (phdr->p_filesz)
 100                         memcpy(dst, src, phdr->p_filesz);
 101                 if (phdr->p_filesz != phdr->p_memsz)
 102                         memset(dst + phdr->p_filesz, 0x00,
 103                                phdr->p_memsz - phdr->p_filesz);
 104                 flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
 105                             roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
 106         }
 107
 108         if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
 109                                             EF_PPC64_ELFV1_ABI)) {
 110                 /*
 111                  * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
 112                  * descriptor pointer with the first double word being the
 113                  * address of the entry point of the function.
 114                  */
 115                 uintptr_t addr = ehdr->e_entry;
 116
 117                 return *(Elf64_Addr *)addr;
 118         }
 119
 120         return ehdr->e_entry;
 121 }
 122
 123 unsigned long load_elf64_image_shdr(unsigned long addr)
 124 {
 125         Elf64_Ehdr *ehdr; /* Elf header structure pointer */
 126         Elf64_Shdr *shdr; /* Section header structure pointer */
 127         unsigned char *strtab = 0; /* String table pointer */
 128         unsigned char *image; /* Binary image pointer */
 129         int i; /* Loop counter */
 130
 131         ehdr = (Elf64_Ehdr *)addr;
 132
 133         /* Find the section header string table for output info */
 134         shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
 135                              (ehdr->e_shstrndx * sizeof(Elf64_Shdr)));
 136
 137         if (shdr->sh_type == SHT_STRTAB)
 138                 strtab = (unsigned char *)(addr + (ulong)shdr->sh_offset);
 139
 140         /* Load each appropriate section */
 141         for (i = 0; i < ehdr->e_shnum; ++i) {
 142                 shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
 143                                      (i * sizeof(Elf64_Shdr)));
 144
 145                 if (!(shdr->sh_flags & SHF_ALLOC) ||
 146                     shdr->sh_addr == 0 || shdr->sh_size == 0) {
 147                         continue;
 148                 }
 149
 150                 if (strtab) {
 151                         debug("%sing %s @ 0x%08lx (%ld bytes)\n",
 152                               (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
 153                                &strtab[shdr->sh_name],
 154                                (unsigned long)shdr->sh_addr,
 155                                (long)shdr->sh_size);
 156                 }
 157
 158                 if (shdr->sh_type == SHT_NOBITS) {
 159                         memset((void *)(uintptr_t)shdr->sh_addr, 0,
 160                                shdr->sh_size);
 161                 } else {
 162                         image = (unsigned char *)addr + (ulong)shdr->sh_offset;
 163                         memcpy((void *)(uintptr_t)shdr->sh_addr,
 164                                (const void *)image, shdr->sh_size);
 165                 }
 166                 flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
 167                             roundup((shdr->sh_addr + shdr->sh_size),
 168                                      ARCH_DMA_MINALIGN) -
 169                                 rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
 170         }
 171
 172         if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
 173                                             EF_PPC64_ELFV1_ABI)) {
 174                 /*
 175                  * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
 176                  * descriptor pointer with the first double word being the
 177                  * address of the entry point of the function.
 178                  */
 179                 uintptr_t addr = ehdr->e_entry;
 180
 181                 return *(Elf64_Addr *)addr;
 182         }
 183
 184         return ehdr->e_entry;
 185 }
 186
 187 /*
 188  * A very simple ELF loader, assumes the image is valid, returns the
 189  * entry point address.
 190  *
 191  * The loader firstly reads the EFI class to see if it's a 64-bit image.
 192  * If yes, call the ELF64 loader. Otherwise continue with the ELF32 loader.
 193  */
 194 unsigned long load_elf_image_phdr(unsigned long addr)
 195 {
 196         Elf32_Ehdr *ehdr; /* Elf header structure pointer */
 197         Elf32_Phdr *phdr; /* Program header structure pointer */
 198         int i;
 199
 200         ehdr = (Elf32_Ehdr *)addr;
 201         if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
 202                 return load_elf64_image_phdr(addr);
 203
 204         phdr = (Elf32_Phdr *)(addr + ehdr->e_phoff);
 205
 206         /* Load each program header */
 207         for (i = 0; i < ehdr->e_phnum; ++i, ++phdr) {
 208                 void *dst = (void *)(uintptr_t)phdr->p_paddr;
 209                 void *src = (void *)addr + phdr->p_offset;
 210
 211                 /* Only load PT_LOAD program header */
 212                 if (phdr->p_type != PT_LOAD)
 213                         continue;
 214
 215                 debug("Loading phdr %i to 0x%p (%i bytes)\n",
 216                       i, dst, phdr->p_filesz);
 217                 if (phdr->p_filesz)
 218                         memcpy(dst, src, phdr->p_filesz);
 219                 if (phdr->p_filesz != phdr->p_memsz)
 220                         memset(dst + phdr->p_filesz, 0x00,
 221                                phdr->p_memsz - phdr->p_filesz);
 222                 flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
 223                             roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
 224         }
 225
 226         return ehdr->e_entry;
 227 }
 228
 229 unsigned long load_elf_image_shdr(unsigned long addr)
 230 {
 231         Elf32_Ehdr *ehdr; /* Elf header structure pointer */
 232         Elf32_Shdr *shdr; /* Section header structure pointer */
 233         unsigned char *strtab = 0; /* String table pointer */
 234         unsigned char *image; /* Binary image pointer */
 235         int i; /* Loop counter */
 236
 237         ehdr = (Elf32_Ehdr *)addr;
 238         if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
 239                 return load_elf64_image_shdr(addr);
 240
 241         /* Find the section header string table for output info */
 242         shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
 243                              (ehdr->e_shstrndx * sizeof(Elf32_Shdr)));
 244
 245         if (shdr->sh_type == SHT_STRTAB)
 246                 strtab = (unsigned char *)(addr + shdr->sh_offset);
 247
 248         /* Load each appropriate section */
 249         for (i = 0; i < ehdr->e_shnum; ++i) {
 250                 shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
 251                                      (i * sizeof(Elf32_Shdr)));
 252
 253                 if (!(shdr->sh_flags & SHF_ALLOC) ||
 254                     shdr->sh_addr == 0 || shdr->sh_size == 0) {
 255                         continue;
 256                 }
 257
 258                 if (strtab) {
 259                         debug("%sing %s @ 0x%08lx (%ld bytes)\n",
 260                               (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
 261                                &strtab[shdr->sh_name],
 262                                (unsigned long)shdr->sh_addr,
 263                                (long)shdr->sh_size);
 264                 }
 265
 266                 if (shdr->sh_type == SHT_NOBITS) {
 267                         memset((void *)(uintptr_t)shdr->sh_addr, 0,
 268                                shdr->sh_size);
 269                 } else {
 270                         image = (unsigned char *)addr + shdr->sh_offset;
 271                         memcpy((void *)(uintptr_t)shdr->sh_addr,
 272                                (const void *)image, shdr->sh_size);
 273                 }
 274                 flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
 275                             roundup((shdr->sh_addr + shdr->sh_size),
 276                                     ARCH_DMA_MINALIGN) -
 277                             rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
 278         }
 279
 280         return ehdr->e_entry;
 281 }
 282
 283 /*
 284  * Determine if a valid ELF image exists at the given memory location.
 285  * First look at the ELF header magic field, then make sure that it is
 286  * executable.
 287  */
 288 int valid_elf_image(unsigned long addr)
 289 {
 290         Elf32_Ehdr *ehdr; /* Elf header structure pointer */
 291
 292         ehdr = (Elf32_Ehdr *)addr;
 293
 294         if (!IS_ELF(*ehdr)) {
 295                 printf("## No elf image at address 0x%08lx\n", addr);
 296                 return 0;
 297         }
 298
 299         if (ehdr->e_type != ET_EXEC) {
 300                 printf("## Not a 32-bit elf image at address 0x%08lx\n", addr);
 301                 return 0;
 302         }
 303
 304         return 1;
 305 }