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