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+ Boot image header in RISC-V Linux
+ =============================================
+
+Author: Atish Patra <atish.patra@wdc.com>
+Date : 20 May 2019
+
+This document only describes the boot image header details for RISC-V Linux.
+The complete booting guide will be available at Documentation/riscv/booting.txt.
+
+The following 64-byte header is present in decompressed Linux kernel image.
+
+ u32 code0; /* Executable code */
+ u32 code1; /* Executable code */
+ u64 text_offset; /* Image load offset, little endian */
+ u64 image_size; /* Effective Image size, little endian */
+ u64 flags; /* kernel flags, little endian */
+ u32 version; /* Version of this header */
+ u32 res1 = 0; /* Reserved */
+ u64 res2 = 0; /* Reserved */
+ u64 magic = 0x5643534952; /* Magic number, little endian, "RISCV" */
+ u32 res3; /* Reserved for additional RISC-V specific header */
+ u32 res4; /* Reserved for PE COFF offset */
+
+This header format is compliant with PE/COFF header and largely inspired from
+ARM64 header. Thus, both ARM64 & RISC-V header can be combined into one common
+header in future.
+
+Notes:
+- This header can also be reused to support EFI stub for RISC-V in future. EFI
+ specification needs PE/COFF image header in the beginning of the kernel image
+ in order to load it as an EFI application. In order to support EFI stub,
+ code0 should be replaced with "MZ" magic string and res5(at offset 0x3c) should
+ point to the rest of the PE/COFF header.
+
+- version field indicate header version number.
+ Bits 0:15 - Minor version
+ Bits 16:31 - Major version
+
+ This preserves compatibility across newer and older version of the header.
+ The current version is defined as 0.1.
+
+- res3 is reserved for offset to any other additional fields. This makes the
+ header extendible in future. One example would be to accommodate ISA
+ extension for RISC-V in future. For current version, it is set to be zero.
+
+- In current header, the flag field has only one field.
+ Bit 0: Kernel endianness. 1 if BE, 0 if LE.
+
+- Image size is mandatory for boot loader to load kernel image. Booting will
+ fail otherwise.