3 # SPDX-License-Identifier: BSD-2-Clause
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
31 gBytesOut = 0; # How many output bytes we've written so far
32 gKernbase = 0; # Address of first byte of loaded kernel image
33 gStart = 0; # Address of _start symbol
34 gStartOff = 0; # Offset of _start symbol from start of image
35 gEnd = 0; # Address of _end symbol
36 gEndOff = 0; # Offset of _end symbol from start of image
38 # The type of header we're writing is set using -v hdrtype= on
39 # the command line, ensure we got a valid value for it.
40 if (hdrtype != "v7jump" &&
41 hdrtype != "v8jump" &&
42 hdrtype != "v8booti") {
43 print "arm_kernel_boothdr.awk: " \
44 "missing or invalid '-v hdrtype=' argument" >"/dev/stderr"
45 gHdrType = "error_reported"
52 function addr_to_offset(addr) {
53 # Turn an address into an offset from the start of the loaded image.
54 return addr % gKernbase
57 function hexstr_to_num(str) {
59 # Prepend a 0x onto the string, then coerce it to a number by doing
60 # arithmetic with it, which makes awk run it through strtod(),
61 # which handles hex numbers that have a 0x prefix.
66 function write_le32(num) {
68 for (i = 0; i < 4; i++) {
69 printf("%c", num % 256);
75 function write_le64(num) {
77 for (i = 0; i < 8; i++) {
78 printf("%c", num % 256);
84 function write_padding() {
86 # Write enough padding bytes so that the header fills all the
87 # remaining space before the _start symbol.
89 while (gBytesOut++ < gStartOff) {
94 function write_v7jump() {
96 # Write the machine code for "b _start"...
97 # 0xea is armv7 "branch always" and the low 24 bits is the signed
98 # offset from the current PC, in words. We know the gStart offset
99 # is in the first 2mb, so it'll fit in 24 bits.
101 write_le32(hexstr_to_num("ea000000") + (gStartOff / 4) - 2)
104 function write_v8jump() {
106 # Write the machine code for "b _start"...
107 # 0x14 is armv8 "branch always" and the low 26 bits is the signed
108 # offset from the current PC, in words. We know the gStart offset
109 # is in the first 2mb, so it'll fit in 26 bits.
111 write_le32(hexstr_to_num("14000000") + (gStartOff / 4))
114 function write_v8booti() {
116 # We are writing this struct...
118 # struct Image_header {
119 # uint32_t code0; /* Executable code */
120 # uint32_t code1; /* Executable code */
121 # uint64_t text_offset; /* Image load offset, LE */
122 # uint64_t image_size; /* Effective Image size, LE */
123 # uint64_t flags; /* Kernel flags, LE */
124 # uint64_t res1[3]; /* reserved */
125 # uint32_t magic; /* Magic number */
129 # We write 'b _start' into code0. The image size is everything from
130 # the start of the loaded image to the offset given by the _end symbol.
132 write_v8jump() # code0
133 write_le32(0) # code1
134 write_le64(0) # text_offset
135 write_le64(gEndOff) # image_size
136 write_le64(hexstr_to_num("8")) # flags
137 write_le64(0) # res1[0]
138 write_le64(0) # res1[1]
139 write_le64(0) # res1[2]
140 write_le32(hexstr_to_num("644d5241")) # magic (LE "ARMd" (d is 0x64))
145 # If the symbol name is exactly "kernbase" save its address.
146 if ($3 == "kernbase") {
147 gKernbase = hexstr_to_num($1)
152 # If the symbol name is exactly "_start" save its address.
153 if ($3 == "_start") {
154 gStart = hexstr_to_num($1)
159 # If the symbol name is exactly "_end" remember its value.
161 gEnd = hexstr_to_num($1)
166 # Note that this function runs even if BEGIN calls exit(1)!
167 if (gHdrType == "error_reported") {
171 # Make sure we got all three required symbols.
172 if (gKernbase == 0 || gStart == 0 || gEnd == 0) {
173 print "arm_kernel_boothdr.awk: " \
174 "missing kernbase/_start/_end symbol(s)" >"/dev/stderr"
178 gStartOff = addr_to_offset(gStart)
179 gEndOff = addr_to_offset(gEnd)
181 if (gHdrType == "v7jump") {
183 } else if (gHdrType == "v8jump") {
185 } else if (gHdrType == "v8booti") {