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| -rw-r--r-- | Documentation/arch/x86/boot.rst | 40 |
1 files changed, 21 insertions, 19 deletions
diff --git a/Documentation/arch/x86/boot.rst b/Documentation/arch/x86/boot.rst index 17a7da883895..069073ecc87e 100644 --- a/Documentation/arch/x86/boot.rst +++ b/Documentation/arch/x86/boot.rst @@ -77,7 +77,7 @@ Protocol 2.14 BURNT BY INCORRECT COMMIT Protocol 2.15 (Kernel 5.5) Added the kernel_info and kernel_info.setup_type_max. ============= ============================================================ - .. note:: +.. note:: The protocol version number should be changed only if the setup header is changed. There is no need to update the version number if boot_params or kernel_info are changed. Additionally, it is recommended to use @@ -229,14 +229,14 @@ Offset/Size Proto Name Meaning =========== ======== ===================== ============================================ .. note:: - (1) For backwards compatibility, if the setup_sects field contains 0, the - real value is 4. + (1) For backwards compatibility, if the setup_sects field contains 0, + the real value is 4. - (2) For boot protocol prior to 2.04, the upper two bytes of the syssize - field are unusable, which means the size of a bzImage kernel - cannot be determined. + (2) For boot protocol prior to 2.04, the upper two bytes of the syssize + field are unusable, which means the size of a bzImage kernel + cannot be determined. - (3) Ignored, but safe to set, for boot protocols 2.02-2.09. + (3) Ignored, but safe to set, for boot protocols 2.02-2.09. If the "HdrS" (0x53726448) magic number is not found at offset 0x202, the boot protocol version is "old". Loading an old kernel, the @@ -265,7 +265,7 @@ All general purpose boot loaders should write the fields marked nonstandard address should fill in the fields marked (reloc); other boot loaders can ignore those fields. -The byte order of all fields is littleendian (this is x86, after all.) +The byte order of all fields is little endian (this is x86, after all.) ============ =========== Field name: setup_sects @@ -1206,10 +1206,11 @@ bit (LOAD_HIGH) in the loadflags field is set:: is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01); load_address = is_bzImage ? 0x100000 : 0x10000; -Note that Image/zImage kernels can be up to 512K in size, and thus use -the entire 0x10000-0x90000 range of memory. This means it is pretty -much a requirement for these kernels to load the real-mode part at -0x90000. bzImage kernels allow much more flexibility. +.. note:: + Image/zImage kernels can be up to 512K in size, and thus use the entire + 0x10000-0x90000 range of memory. This means it is pretty much a + requirement for these kernels to load the real-mode part at 0x90000. + bzImage kernels allow much more flexibility. Special Command Line Options ============================ @@ -1439,12 +1440,13 @@ The boot loader *must* fill out the following fields in bp:: All other fields should be zero. -NOTE: The EFI Handover Protocol is deprecated in favour of the ordinary PE/COFF - entry point, combined with the LINUX_EFI_INITRD_MEDIA_GUID based initrd - loading protocol (refer to [0] for an example of the bootloader side of - this), which removes the need for any knowledge on the part of the EFI - bootloader regarding the internal representation of boot_params or any - requirements/limitations regarding the placement of the command line - and ramdisk in memory, or the placement of the kernel image itself. +.. note:: + The EFI Handover Protocol is deprecated in favour of the ordinary PE/COFF + entry point, combined with the LINUX_EFI_INITRD_MEDIA_GUID based initrd + loading protocol (refer to [0] for an example of the bootloader side of + this), which removes the need for any knowledge on the part of the EFI + bootloader regarding the internal representation of boot_params or any + requirements/limitations regarding the placement of the command line + and ramdisk in memory, or the placement of the kernel image itself. [0] https://github.com/u-boot/u-boot/commit/ec80b4735a593961fe701cc3a5d717d4739b0fd0 |