1 =================================
2 Boot image header in RISC-V Linux
3 =================================
4
5 :Author: Atish Patra <atish.patra@wdc.com>
6 :Date: 20 May 2019
7
8 This document only describes the boot image he
9
10 The following 64-byte header is present in dec
11
12 u32 code0; /* Executabl
13 u32 code1; /* Executabl
14 u64 text_offset; /* Image loa
15 u64 image_size; /* Effective
16 u64 flags; /* kernel fl
17 u32 version; /* Version o
18 u32 res1 = 0; /* Reserved
19 u64 res2 = 0; /* Reserved
20 u64 magic = 0x5643534952; /* Magic num
21 u32 magic2 = 0x05435352; /* Magic num
22 u32 res3; /* Reserved
23
24 This header format is compliant with PE/COFF h
25 ARM64 header. Thus, both ARM64 & RISC-V header
26 header in future.
27
28 Notes
29 =====
30
31 - This header is also reused to support EFI st
32 needs PE/COFF image header in the beginning
33 load it as an EFI application. In order to s
34 with "MZ" magic string and res3(at offset 0x
35 PE/COFF header.
36
37 - version field indicate header version number
38
39 ========== =============
40 Bits 0:15 Minor version
41 Bits 16:31 Major version
42 ========== =============
43
44 This preserves compatibility across newer an
45 The current version is defined as 0.2.
46
47 - The "magic" field is deprecated as of versio
48 release, it may be removed. This originally
49 with the ARM64 header "magic" field, but unf
50 The "magic2" field replaces it, matching up
51
52 - In current header, the flags field has only
53
54 ===== ===============================
55 Bit 0 Kernel endianness. 1 if BE, 0 i
56 ===== ===============================
57
58 - Image size is mandatory for boot loader to l
59 fail otherwise.
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