diff options
Diffstat (limited to 'Documentation/x86/boot.txt')
| -rw-r--r-- | Documentation/x86/boot.txt | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index 9efceff..b443f1d 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -57,6 +57,10 @@ Protocol 2.10: (Kernel 2.6.31) Added a protocol for relaxed alignment Protocol 2.11: (Kernel 3.6) Added a field for offset of EFI handover protocol entry point. +Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields + to struct boot_params for for loading bzImage and ramdisk + above 4G in 64bit. + **** MEMORY LAYOUT The traditional memory map for the kernel loader, used for Image or @@ -182,7 +186,7 @@ Offset Proto Name Meaning 0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel 0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not 0235/1 2.10+ min_alignment Minimum alignment, as a power of two -0236/2 N/A pad3 Unused +0236/2 2.12+ xloadflags Boot protocol option flags 0238/4 2.06+ cmdline_size Maximum size of the kernel command line 023C/4 2.07+ hardware_subarch Hardware subarchitecture 0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data @@ -373,7 +377,7 @@ Protocol: 2.00+ 1 Loadlin 2 bootsect-loader (0x20, all other values reserved) 3 Syslinux - 4 Etherboot/gPXE + 4 Etherboot/gPXE/iPXE 5 ELILO 7 GRUB 8 U-Boot @@ -381,10 +385,12 @@ Protocol: 2.00+ A Gujin B Qemu C Arcturus Networks uCbootloader + D kexec-tools E Extended (see ext_loader_type) F Special (0xFF = undefined) 10 Reserved 11 Minimal Linux Bootloader <http://sebastian-plotz.blogspot.de> + 12 OVMF UEFI virtualization stack Please contact <hpa@zytor.com> if you need a bootloader ID value assigned. @@ -581,6 +587,27 @@ Protocol: 2.10+ misaligned kernel. Therefore, a loader should typically try each power-of-two alignment from kernel_alignment down to this alignment. +Field name: xloadflags +Type: read +Offset/size: 0x236/2 +Protocol: 2.12+ + + This field is a bitmask. + + Bit 0 (read): XLF_KERNEL_64 + - If 1, this kernel has the legacy 64-bit entry point at 0x200. + + Bit 1 (read): XLF_CAN_BE_LOADED_ABOVE_4G + - If 1, kernel/boot_params/cmdline/ramdisk can be above 4G. + + Bit 2 (read): XLF_EFI_HANDOVER_32 + - If 1, the kernel supports the 32-bit EFI handoff entry point + given at handover_offset. + + Bit 3 (read): XLF_EFI_HANDOVER_64 + - If 1, the kernel supports the 64-bit EFI handoff entry point + given at handover_offset + 0x200. + Field name: cmdline_size Type: read Offset/size: 0x238/4 @@ -1013,7 +1040,7 @@ boot_params as that of 16-bit boot protocol, the boot loader should also fill the additional fields of the struct boot_params as that described in zero-page.txt. -After setupping the struct boot_params, the boot loader can load the +After setting up the struct boot_params, the boot loader can load the 32/64-bit kernel in the same way as that of 16-bit boot protocol. In 32-bit boot protocol, the kernel is started by jumping to the @@ -1023,7 +1050,7 @@ In 32-bit boot protocol, the kernel is started by jumping to the At entry, the CPU must be in 32-bit protected mode with paging disabled; a GDT must be loaded with the descriptors for selectors __BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat -segment; __BOOS_CS must have execute/read permission, and __BOOT_DS +segment; __BOOT_CS must have execute/read permission, and __BOOT_DS must have read/write permission; CS must be __BOOT_CS and DS, ES, SS must be __BOOT_DS; interrupt must be disabled; %esi must hold the base address of the struct boot_params; %ebp, %edi and %ebx must be zero. |
