diff options
Diffstat (limited to 'pc-bios/optionrom')
| -rw-r--r-- | pc-bios/optionrom/linuxboot.S | 37 |
1 files changed, 27 insertions, 10 deletions
diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S index 5bc0af08e0..ba821ab922 100644 --- a/pc-bios/optionrom/linuxboot.S +++ b/pc-bios/optionrom/linuxboot.S @@ -76,7 +76,31 @@ boot_kernel: copy_kernel: - /* Compute initrd address */ + /* Read info block in low memory (0x10000 or 0x90000) */ + read_fw FW_CFG_SETUP_ADDR + shr $4, %eax + mov %eax, %es + xor %edi, %edi + read_fw_blob_addr32_edi(FW_CFG_SETUP) + + cmpw $0x203, %es:0x206 // if protocol >= 0x203 + jae 1f // have initrd_max + movl $0x37ffffff, %es:0x22c // else assume 0x37ffffff +1: + + /* Check if using kernel-specified initrd address */ + read_fw FW_CFG_INITRD_ADDR + mov %eax, %edi // (load_kernel wants it in %edi) + read_fw FW_CFG_INITRD_SIZE // find end of initrd + add %edi, %eax + xor %es:0x22c, %eax // if it matches es:0x22c + and $-4096, %eax // (apart from padding for page) + jz load_kernel // then initrd is not at top + // of memory + + /* pc.c placed the initrd at end of memory. Compute a better + * initrd address based on e801 data. + */ mov $0xe801, %ax xor %cx, %cx xor %dx, %dx @@ -107,7 +131,9 @@ copy_kernel: read_fw FW_CFG_INITRD_SIZE subl %eax, %edi andl $-4096, %edi /* EDI = start of initrd */ + movl %edi, %es:0x218 /* put it in the header */ +load_kernel: /* We need to load the kernel into memory we can't access in 16 bit mode, so let's get into 32 bit mode, write the kernel and jump back again. */ @@ -139,19 +165,10 @@ copy_kernel: /* We're now running in 16-bit CS, but 32-bit ES! */ /* Load kernel and initrd */ - pushl %edi read_fw_blob_addr32_edi(FW_CFG_INITRD) read_fw_blob_addr32(FW_CFG_KERNEL) read_fw_blob_addr32(FW_CFG_CMDLINE) - read_fw FW_CFG_SETUP_ADDR - mov %eax, %edi - mov %eax, %ebx - read_fw_blob_addr32_edi(FW_CFG_SETUP) - - /* Update the header with the initrd address we chose above */ - popl %es:0x218(%ebx) - /* And now jump into Linux! */ mov $0, %eax mov %eax, %cr0 |