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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-27 09:32:30 +0200 |
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| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-27 09:32:30 +0200 |
| commit | f6402eb4a2b3192bdf23fa39ef8e85fd3691cca9 (patch) | |
| tree | da8d55cd97d59cfe689fe447d98637204f2218e3 /Documentation/x86/boot.rst | |
| parent | 992a60ed0d5e312ce9a485c9e12097ac82ae4b3e (diff) | |
| parent | 6a8b55ed4056ea5559ebe4f6a4b247f627870d4c (diff) | |
| download | lwn-f6402eb4a2b3192bdf23fa39ef8e85fd3691cca9.tar.gz lwn-f6402eb4a2b3192bdf23fa39ef8e85fd3691cca9.zip | |
Merge 5.7-rc3 into usb-next
We need the USB fixes in here too.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/x86/boot.rst')
| -rw-r--r-- | Documentation/x86/boot.rst | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst index fa7ddc0428c8..5325c71ca877 100644 --- a/Documentation/x86/boot.rst +++ b/Documentation/x86/boot.rst @@ -1399,8 +1399,8 @@ must have read/write permission; CS must be __BOOT_CS and DS, ES, SS must be __BOOT_DS; interrupt must be disabled; %rsi must hold the base address of the struct boot_params. -EFI Handover Protocol -===================== +EFI Handover Protocol (deprecated) +================================== This protocol allows boot loaders to defer initialisation to the EFI boot stub. The boot loader is required to load the kernel/initrd(s) @@ -1408,6 +1408,12 @@ from the boot media and jump to the EFI handover protocol entry point which is hdr->handover_offset bytes from the beginning of startup_{32,64}. +The boot loader MUST respect the kernel's PE/COFF metadata when it comes +to section alignment, the memory footprint of the executable image beyond +the size of the file itself, and any other aspect of the PE/COFF header +that may affect correct operation of the image as a PE/COFF binary in the +execution context provided by the EFI firmware. + The function prototype for the handover entry point looks like this:: efi_main(void *handle, efi_system_table_t *table, struct boot_params *bp) @@ -1419,9 +1425,18 @@ UEFI specification. 'bp' is the boot loader-allocated boot params. The boot loader *must* fill out the following fields in bp:: - - hdr.code32_start - hdr.cmd_line_ptr - hdr.ramdisk_image (if applicable) - hdr.ramdisk_size (if applicable) 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. + +[0] https://github.com/u-boot/u-boot/commit/ec80b4735a593961fe701cc3a5d717d4739b0fd0 |