lib/relocator
This commit is contained in:
Vladimir 'phcoder' Serbinenko
parent
f84114f583
commit
e7573c5ce2
9 changed files with 509 additions and 120 deletions
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@ -48,18 +48,35 @@
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#include <grub/device.h>
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#include <grub/partition.h>
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#endif
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#include <grub/i386/relocator.h>
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extern grub_dl_t my_mod;
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static struct grub_multiboot_info *mbi, *mbi_dest;
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static grub_addr_t entry;
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static char *playground;
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static grub_size_t code_size;
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char *grub_multiboot_payload_orig;
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grub_addr_t grub_multiboot_payload_dest;
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grub_size_t grub_multiboot_payload_size;
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grub_uint32_t grub_multiboot_payload_eip;
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grub_uint32_t grub_multiboot_payload_esp;
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static grub_err_t
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grub_multiboot_boot (void)
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{
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grub_multiboot_real_boot (entry, mbi_dest);
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struct grub_relocator32_state state =
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{
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.eax = MULTIBOOT_MAGIC2,
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.ebx = PTR_TO_UINT32 (mbi_dest),
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.ecx = 0,
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.edx = 0,
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.eip = grub_multiboot_payload_eip,
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.esp = grub_multiboot_payload_esp
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};
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grub_relocator32_boot (grub_multiboot_payload_orig,
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grub_multiboot_payload_dest,
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state);
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/* Not reached. */
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return GRUB_ERR_NONE;
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@ -248,11 +265,8 @@ grub_multiboot (int argc, char *argv[])
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goto fail;
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}
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if (playground)
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{
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grub_free (playground);
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playground = NULL;
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}
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grub_relocator32_free (grub_multiboot_payload_orig);
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grub_multiboot_payload_orig = NULL;
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mmap_length = grub_get_multiboot_mmap_len ();
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@ -267,11 +281,13 @@ grub_multiboot (int argc, char *argv[])
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((void *) ((x) + code_size + cmdline_length))
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#define mbi_addr(x) ((void *) ((x) + code_size + cmdline_length + boot_loader_name_length))
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#define mmap_addr(x) ((void *) ((x) + code_size + cmdline_length + boot_loader_name_length + sizeof (struct grub_multiboot_info)))
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#define stack_addr(x) ((void *) ((x) + code_size + cmdline_length + boot_loader_name_length + sizeof (struct grub_multiboot_info) + mmap_length + GRUB_MULTIBOOT_STACK_SIZE))
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grub_multiboot_payload_size = cmdline_length
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/* boot_loader_name_length might need to grow for mbi,etc to be aligned (see below) */
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+ boot_loader_name_length + 3
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+ sizeof (struct grub_multiboot_info) + mmap_length;
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+ sizeof (struct grub_multiboot_info) + mmap_length
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+ GRUB_MULTIBOOT_STACK_SIZE;
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if (header->flags & MULTIBOOT_AOUT_KLUDGE)
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{
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@ -287,11 +303,12 @@ grub_multiboot (int argc, char *argv[])
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grub_multiboot_payload_dest = header->load_addr;
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grub_multiboot_payload_size += code_size;
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playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
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if (! playground)
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goto fail;
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grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
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grub_multiboot_payload_orig
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= grub_relocator32_alloc (grub_multiboot_payload_size);
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if (! grub_multiboot_payload_orig)
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goto fail;
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if ((grub_file_seek (file, offset)) == (grub_off_t) - 1)
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goto fail;
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@ -304,7 +321,7 @@ grub_multiboot (int argc, char *argv[])
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grub_memset ((void *) (grub_multiboot_payload_orig + load_size), 0,
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header->bss_end_addr - header->load_addr - load_size);
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grub_multiboot_payload_entry_offset = header->entry_addr - header->load_addr;
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grub_multiboot_payload_eip = header->entry_addr;
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}
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else if (grub_multiboot_load_elf (file, buffer) != GRUB_ERR_NONE)
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@ -325,23 +342,6 @@ grub_multiboot (int argc, char *argv[])
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mbi->mmap_addr = (grub_uint32_t) mmap_addr (grub_multiboot_payload_dest);
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mbi->flags |= MULTIBOOT_INFO_MEM_MAP;
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if (grub_multiboot_payload_dest >= grub_multiboot_payload_orig)
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{
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grub_memmove (playground, &grub_multiboot_forward_relocator, RELOCATOR_SIZEOF(forward));
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entry = (grub_addr_t) playground;
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}
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else
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{
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grub_memmove ((char *) (grub_multiboot_payload_orig + grub_multiboot_payload_size),
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&grub_multiboot_backward_relocator, RELOCATOR_SIZEOF(backward));
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entry = (grub_addr_t) grub_multiboot_payload_orig + grub_multiboot_payload_size;
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}
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grub_dprintf ("multiboot_loader", "dest=%p, size=0x%x, entry_offset=0x%x\n",
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(void *) grub_multiboot_payload_dest,
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grub_multiboot_payload_size,
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grub_multiboot_payload_entry_offset);
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/* Convert from bytes to kilobytes. */
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mbi->mem_lower = grub_mmap_get_lower () / 1024;
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mbi->mem_upper = grub_mmap_get_upper () / 1024;
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@ -371,6 +371,8 @@ grub_multiboot (int argc, char *argv[])
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if (grub_multiboot_get_bootdev (&mbi->boot_device))
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mbi->flags |= MULTIBOOT_INFO_BOOTDEV;
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grub_multiboot_payload_esp = PTR_TO_UINT32 (stack_addr (grub_multiboot_payload_dest));
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grub_loader_set (grub_multiboot_boot, grub_multiboot_unload, 1);
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fail:
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@ -32,6 +32,8 @@
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#error "I'm confused"
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#endif
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#include <grub/i386/relocator.h>
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#define CONCAT(a,b) CONCAT_(a, b)
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#define CONCAT_(a,b) a ## b
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@ -99,11 +101,12 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, void *buffer)
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grub_multiboot_payload_dest = phdr(lowest_segment)->p_paddr;
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grub_multiboot_payload_size += code_size;
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playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
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if (! playground)
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return grub_errno;
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grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
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grub_multiboot_payload_orig
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= grub_relocator32_alloc (grub_multiboot_payload_size);
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if (!grub_multiboot_payload_orig)
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return grub_errno;
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/* Load every loadable segment in memory. */
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for (i = 0; i < ehdr->e_phnum; i++)
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@ -135,8 +138,7 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, void *buffer)
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if (phdr(i)->p_vaddr <= ehdr->e_entry
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&& phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry)
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{
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grub_multiboot_payload_entry_offset = (ehdr->e_entry - phdr(i)->p_vaddr)
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+ (phdr(i)->p_paddr - phdr(lowest_segment)->p_paddr);
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grub_multiboot_payload_eip = ehdr->e_entry;
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break;
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}
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@ -22,81 +22,6 @@
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.p2align 2 /* force 4-byte alignment */
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/*
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* This starts the multiboot kernel.
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*/
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VARIABLE(grub_multiboot_payload_size)
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.long 0
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VARIABLE(grub_multiboot_payload_orig)
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.long 0
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VARIABLE(grub_multiboot_payload_dest)
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.long 0
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VARIABLE(grub_multiboot_payload_entry_offset)
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.long 0
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/*
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* The relocators below understand the following parameters:
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* ecx: Size of the block to be copied.
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* esi: Where to copy from (always lowest address, even if we're relocating
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* backwards).
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* edi: Where to copy to (likewise).
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* edx: Offset of the entry point (relative to the beginning of the block).
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*/
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VARIABLE(grub_multiboot_forward_relocator)
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/* Add entry offset. */
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addl %edi, %edx
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/* Forward copy. */
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cld
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rep
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movsb
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jmp *%edx
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VARIABLE(grub_multiboot_forward_relocator_end)
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VARIABLE(grub_multiboot_backward_relocator)
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/* Add entry offset (before %edi is mangled). */
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addl %edi, %edx
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/* Backward movsb is implicitly off-by-one. compensate that. */
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decl %esi
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decl %edi
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/* Backward copy. */
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std
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addl %ecx, %esi
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addl %ecx, %edi
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rep
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movsb
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cld
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jmp *%edx
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VARIABLE(grub_multiboot_backward_relocator_end)
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FUNCTION(grub_multiboot_real_boot)
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/* Push the entry address on the stack. */
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pushl %eax
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/* Move the address of the multiboot information structure to ebx. */
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movl %edx,%ebx
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/* Interrupts should be disabled. */
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cli
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/* Where do we copy what from. */
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movl EXT_C(grub_multiboot_payload_size), %ecx
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movl EXT_C(grub_multiboot_payload_orig), %esi
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movl EXT_C(grub_multiboot_payload_dest), %edi
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movl EXT_C(grub_multiboot_payload_entry_offset), %edx
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/* Move the magic value into eax. */
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movl $MULTIBOOT_MAGIC2, %eax
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/* Jump to the relocator. */
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popl %ebp
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jmp *%ebp
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/*
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* This starts the multiboot 2 kernel.
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*/
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