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diff --git a/Documentation/arm/uefi.rst b/Documentation/arm/uefi.rst deleted file mode 100644 index baebe688a006..000000000000 --- a/Documentation/arm/uefi.rst +++ /dev/null @@ -1,70 +0,0 @@ -================================================ -The Unified Extensible Firmware Interface (UEFI) -================================================ - -UEFI, the Unified Extensible Firmware Interface, is a specification -governing the behaviours of compatible firmware interfaces. It is -maintained by the UEFI Forum - http://www.uefi.org/. - -UEFI is an evolution of its predecessor 'EFI', so the terms EFI and -UEFI are used somewhat interchangeably in this document and associated -source code. As a rule, anything new uses 'UEFI', whereas 'EFI' refers -to legacy code or specifications. - -UEFI support in Linux -===================== -Booting on a platform with firmware compliant with the UEFI specification -makes it possible for the kernel to support additional features: - -- UEFI Runtime Services -- Retrieving various configuration information through the standardised - interface of UEFI configuration tables. (ACPI, SMBIOS, ...) - -For actually enabling [U]EFI support, enable: - -- CONFIG_EFI=y -- CONFIG_EFIVAR_FS=y or m - -The implementation depends on receiving information about the UEFI environment -in a Flattened Device Tree (FDT) - so is only available with CONFIG_OF. - -UEFI stub -========= -The "stub" is a feature that extends the Image/zImage into a valid UEFI -PE/COFF executable, including a loader application that makes it possible to -load the kernel directly from the UEFI shell, boot menu, or one of the -lightweight bootloaders like Gummiboot or rEFInd. - -The kernel image built with stub support remains a valid kernel image for -booting in non-UEFI environments. - -UEFI kernel support on ARM -========================== -UEFI kernel support on the ARM architectures (arm and arm64) is only available -when boot is performed through the stub. - -When booting in UEFI mode, the stub deletes any memory nodes from a provided DT. -Instead, the kernel reads the UEFI memory map. - -The stub populates the FDT /chosen node with (and the kernel scans for) the -following parameters: - -========================== ====== =========================================== -Name Size Description -========================== ====== =========================================== -linux,uefi-system-table 64-bit Physical address of the UEFI System Table. - -linux,uefi-mmap-start 64-bit Physical address of the UEFI memory map, - populated by the UEFI GetMemoryMap() call. - -linux,uefi-mmap-size 32-bit Size in bytes of the UEFI memory map - pointed to in previous entry. - -linux,uefi-mmap-desc-size 32-bit Size in bytes of each entry in the UEFI - memory map. - -linux,uefi-mmap-desc-ver 32-bit Version of the mmap descriptor format. - -kaslr-seed 64-bit Entropy used to randomize the kernel image - base address location. -========================== ====== =========================================== |