src/arch/i386/boot/boot.c

   1 #include <console/console.h>
   2 #include <ip_checksum.h>
   3 #include <boot/elf.h>
   4 #include <boot/elf_boot.h>
   5 #include <string.h>
   6 #include <cpu/x86/multiboot.h>
   7
   8
   9 #ifndef CMD_LINE
  10 #define CMD_LINE ""
  11 #endif
  12
  13
  14
  15 #define UPSZ(X) ((sizeof(X) + 3) &~3)
  16
  17 static struct {
  18         Elf_Bhdr hdr;
  19         Elf_Nhdr ft_hdr;
  20         unsigned char ft_desc[UPSZ(FIRMWARE_TYPE)];
  21         Elf_Nhdr bl_hdr;
  22         unsigned char bl_desc[UPSZ(BOOTLOADER)];
  23         Elf_Nhdr blv_hdr;
  24         unsigned char blv_desc[UPSZ(BOOTLOADER_VERSION)];
  25         Elf_Nhdr cmd_hdr;
  26         unsigned char cmd_desc[UPSZ(CMD_LINE)];
  27 } elf_boot_notes = {
  28         .hdr = {
  29                 .b_signature = 0x0E1FB007,
  30                 .b_size = sizeof(elf_boot_notes),
  31                 .b_checksum = 0,
  32                 .b_records = 4,
  33         },
  34         .ft_hdr = {
  35                 .n_namesz = 0,
  36                 .n_descsz = sizeof(FIRMWARE_TYPE),
  37                 .n_type = EBN_FIRMWARE_TYPE,
  38         },
  39         .ft_desc = FIRMWARE_TYPE,
  40         .bl_hdr = {
  41                 .n_namesz = 0,
  42                 .n_descsz = sizeof(BOOTLOADER),
  43                 .n_type = EBN_BOOTLOADER_NAME,
  44         },
  45         .bl_desc = BOOTLOADER,
  46         .blv_hdr = {
  47                 .n_namesz = 0,
  48                 .n_descsz = sizeof(BOOTLOADER_VERSION),
  49                 .n_type = EBN_BOOTLOADER_VERSION,
  50         },
  51         .blv_desc = BOOTLOADER_VERSION,
  52         .cmd_hdr = {
  53                 .n_namesz = 0,
  54                 .n_descsz = sizeof(CMD_LINE),
  55                 .n_type = EBN_COMMAND_LINE,
  56         },
  57         .cmd_desc = CMD_LINE,
  58 };
  59
  60
  61 int elf_check_arch(Elf_ehdr *ehdr)
  62 {
  63         return (
  64                 ((ehdr->e_machine == EM_386) || (ehdr->e_machine == EM_486)) &&
  65                 (ehdr->e_ident[EI_CLASS] == ELFCLASS32) &&
  66                 (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
  67                 );
  68
  69 }
  70
  71 void jmp_to_elf_entry(void *entry, unsigned long buffer)
  72 {
  73         extern unsigned char _ram_seg, _eram_seg;
  74         unsigned long lb_start, lb_size;
  75         unsigned long adjust, adjusted_boot_notes;
  76         unsigned long type;
  77
  78         elf_boot_notes.hdr.b_checksum =
  79                 compute_ip_checksum(&elf_boot_notes, sizeof(elf_boot_notes));
  80
  81         type = 0x0E1FB007;
  82         lb_start = (unsigned long)&_ram_seg;
  83         lb_size = (unsigned long)(&_eram_seg - &_ram_seg);
  84         adjust = buffer + lb_size - lb_start;
  85
  86         adjusted_boot_notes = (unsigned long)&elf_boot_notes;
  87         adjusted_boot_notes += adjust;
  88
  89         printk_spew("entry    = 0x%08lx\n", (unsigned long)entry);
  90         printk_spew("lb_start = 0x%08lx\n", lb_start);
  91         printk_spew("lb_size  = 0x%08lx\n", lb_size);
  92         printk_spew("adjust   = 0x%08lx\n", adjust);
  93         printk_spew("buffer   = 0x%08lx\n", buffer);
  94         printk_spew("     elf_boot_notes = 0x%08lx\n", (unsigned long)&elf_boot_notes);
  95         printk_spew("adjusted_boot_notes = 0x%08lx\n", adjusted_boot_notes);
  96
  97         /* Jump to kernel */
  98         __asm__ __volatile__(
  99                 "       cld     \n\t"
 100                 /* Save the callee save registers... */
 101                 "       pushl   %%esi\n\t"
 102                 "       pushl   %%edi\n\t"
 103                 "       pushl   %%ebx\n\t"
 104                 /* Save the parameters I was passed */
 105                 "       pushl   $0\n\t" /* 20 adjust */
 106                 "       pushl   %0\n\t" /* 16 lb_start */
 107                 "       pushl   %1\n\t" /* 12 buffer */
 108                 "       pushl   %2\n\t" /*  8 lb_size */
 109                 "       pushl   %3\n\t" /*  4 entry */
 110                 "       pushl   %4\n\t" /*  0 elf_boot_notes */
 111                 /* Compute the adjustment */
 112                 "       xorl    %%eax, %%eax\n\t"
 113                 "       subl    16(%%esp), %%eax\n\t"
 114                 "       addl    12(%%esp), %%eax\n\t"
 115                 "       addl     8(%%esp), %%eax\n\t"
 116                 "       movl    %%eax, 20(%%esp)\n\t"
 117                 /* Place a copy of coreboot in it's new location */
 118                 /* Move ``longs'' the coreboot size is 4 byte aligned */
 119                 "       movl    12(%%esp), %%edi\n\t"
 120                 "       addl     8(%%esp), %%edi\n\t"
 121                 "       movl    16(%%esp), %%esi\n\t"
 122                 "       movl     8(%%esp), %%ecx\n\n"
 123                 "       shrl    $2, %%ecx\n\t"
 124                 "       rep     movsl\n\t"
 125
 126                 /* Adjust the stack pointer to point into the new coreboot image */
 127                 "       addl    20(%%esp), %%esp\n\t"
 128                 /* Adjust the instruction pointer to point into the new coreboot image */
 129                 "       movl    $1f, %%eax\n\t"
 130                 "       addl    20(%%esp), %%eax\n\t"
 131                 "       jmp     *%%eax\n\t"
 132                 "1:     \n\t"
 133
 134                 /* Copy the coreboot bounce buffer over coreboot */
 135                 /* Move ``longs'' the coreboot size is 4 byte aligned */
 136                 "       movl    16(%%esp), %%edi\n\t"
 137                 "       movl    12(%%esp), %%esi\n\t"
 138                 "       movl     8(%%esp), %%ecx\n\t"
 139                 "       shrl    $2, %%ecx\n\t"
 140                 "       rep     movsl\n\t"
 141
 142                 /* Now jump to the loaded image */
 143                 "       movl    %5, %%eax\n\t"
 144                 "       movl     0(%%esp), %%ebx\n\t"
 145                 "       call    *4(%%esp)\n\t"
 146
 147                 /* The loaded image returned? */
 148                 "       cli     \n\t"
 149                 "       cld     \n\t"
 150
 151                 /* Copy the saved copy of coreboot where coreboot runs */
 152                 /* Move ``longs'' the coreboot size is 4 byte aligned */
 153                 "       movl    16(%%esp), %%edi\n\t"
 154                 "       movl    12(%%esp), %%esi\n\t"
 155                 "       addl     8(%%esp), %%esi\n\t"
 156                 "       movl     8(%%esp), %%ecx\n\t"
 157                 "       shrl    $2, %%ecx\n\t"
 158                 "       rep     movsl\n\t"
 159
 160                 /* Adjust the stack pointer to point into the old coreboot image */
 161                 "       subl    20(%%esp), %%esp\n\t"
 162
 163                 /* Adjust the instruction pointer to point into the old coreboot image */
 164                 "       movl    $1f, %%eax\n\t"
 165                 "       subl    20(%%esp), %%eax\n\t"
 166                 "       jmp     *%%eax\n\t"
 167                 "1:     \n\t"
 168
 169                 /* Drop the parameters I was passed */
 170                 "       addl    $24, %%esp\n\t"
 171
 172                 /* Restore the callee save registers */
 173                 "       popl    %%ebx\n\t"
 174                 "       popl    %%edi\n\t"
 175                 "       popl    %%esi\n\t"
 176
 177                 ::
 178                 "g" (lb_start), "g" (buffer), "g" (lb_size),
 179                 "g" (entry),
 180 #if CONFIG_MULTIBOOT
 181                 "g"(mbi), "g" (MB_MAGIC2)
 182 #else
 183                 "g"(adjusted_boot_notes), "g" (0x0E1FB007)
 184 #endif
 185                 );
 186 }
 187
 188