3 # SPDX-License-Identifier: BSD-2-Clause-FreeBSD
5 # Copyright 2019 Ian Lepore <ian@freebsd.org>
7 # Redistribution and use in source and binary forms, with or without
8 # modification, are permitted provided that the following conditions
10 # 1. Redistributions of source code must retain the above copyright
11 # notice, this list of conditions and the following disclaimer.
12 # 2. Redistributions in binary form must reproduce the above copyright
13 # notice, this list of conditions and the following disclaimer in the
14 # documentation and/or other materials provided with the distribution.
16 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 gBytesOut = 0; # How many output bytes we've written so far
33 gKernbase = 0; # Address of first byte of loaded kernel image
34 gStart = 0; # Address of _start symbol
35 gStartOff = 0; # Offset of _start symbol from start of image
36 gEnd = 0; # Address of _end symbol
37 gEndOff = 0; # Offset of _end symbol from start of image
39 # The type of header we're writing is set using -v hdrtype= on
40 # the command line, ensure we got a valid value for it.
41 if (hdrtype != "v7jump" &&
42 hdrtype != "v8jump" &&
43 hdrtype != "v8booti") {
44 print "arm_kernel_boothdr.awk: " \
45 "missing or invalid '-v hdrtype=' argument" >"/dev/stderr"
46 gHdrType = "error_reported"
53 function addr_to_offset(addr) {
54 # Turn an address into an offset from the start of the loaded image.
55 return addr % gKernbase
58 function hexstr_to_num(str) {
60 # Prepend a 0x onto the string, then coerce it to a number by doing
61 # arithmetic with it, which makes awk run it through strtod(),
62 # which handles hex numbers that have a 0x prefix.
67 function write_le32(num) {
69 for (i = 0; i < 4; i++) {
70 printf("%c", num % 256);
76 function write_le64(num) {
78 for (i = 0; i < 8; i++) {
79 printf("%c", num % 256);
85 function write_padding() {
87 # Write enough padding bytes so that the header fills all the
88 # remaining space before the _start symbol.
90 while (gBytesOut++ < gStartOff) {
95 function write_v7jump() {
97 # Write the machine code for "b _start"...
98 # 0xea is armv7 "branch always" and the low 24 bits is the signed
99 # offset from the current PC, in words. We know the gStart offset
100 # is in the first 2mb, so it'll fit in 24 bits.
102 write_le32(hexstr_to_num("ea000000") + (gStartOff / 4) - 2)
105 function write_v8jump() {
107 # Write the machine code for "b _start"...
108 # 0x14 is armv8 "branch always" and the low 26 bits is the signed
109 # offset from the current PC, in words. We know the gStart offset
110 # is in the first 2mb, so it'll fit in 26 bits.
112 write_le32(hexstr_to_num("14000000") + (gStartOff / 4))
115 function write_v8booti() {
117 # We are writing this struct...
119 # struct Image_header {
120 # uint32_t code0; /* Executable code */
121 # uint32_t code1; /* Executable code */
122 # uint64_t text_offset; /* Image load offset, LE */
123 # uint64_t image_size; /* Effective Image size, LE */
124 # uint64_t flags; /* Kernel flags, LE */
125 # uint64_t res1[3]; /* reserved */
126 # uint32_t magic; /* Magic number */
130 # We write 'b _start' into code0. The image size is everything from
131 # the start of the loaded image to the offset given by the _end symbol.
133 write_v8jump() # code0
134 write_le32(0) # code1
135 write_le64(0) # text_offset
136 write_le64(gEndOff) # image_size
137 write_le64(hexstr_to_num("8")) # flags
138 write_le64(0) # res1[0]
139 write_le64(0) # res1[1]
140 write_le64(0) # res1[2]
141 write_le32(hexstr_to_num("644d5241")) # magic (LE "ARMd" (d is 0x64))
146 # If the symbol name is exactly "kernbase" save its address.
147 if ($3 == "kernbase") {
148 gKernbase = hexstr_to_num($1)
153 # If the symbol name is exactly "_start" save its address.
154 if ($3 == "_start") {
155 gStart = hexstr_to_num($1)
160 # If the symbol name is exactly "_end" remember its value.
162 gEnd = hexstr_to_num($1)
167 # Note that this function runs even if BEGIN calls exit(1)!
168 if (gHdrType == "error_reported") {
172 # Make sure we got all three required symbols.
173 if (gKernbase == 0 || gStart == 0 || gEnd == 0) {
174 print "arm_kernel_boothdr.awk: " \
175 "missing kernbase/_start/_end symbol(s)" >"/dev/stderr"
179 gStartOff = addr_to_offset(gStart)
180 gEndOff = addr_to_offset(gEnd)
182 if (gHdrType == "v7jump") {
184 } else if (gHdrType == "v8jump") {
186 } else if (gHdrType == "v8booti") {