2 * Copyright 2015 Mentor Graphics Corporation.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; version 2 of the
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 * vdsomunge - Host program which produces a shared object
19 * architecturally specified to be usable by both soft- and hard-float
22 * The Procedure Call Standard for the ARM Architecture (ARM IHI
25 * 6.4.1 VFP and Base Standard Compatibility
27 * Code compiled for the VFP calling standard is compatible with
28 * the base standard (and vice-versa) if no floating-point or
29 * containerized vector arguments or results are used.
31 * And ELF for the ARM Architecture (ARM IHI 0044E) (Table 4-2) says:
33 * If both EF_ARM_ABI_FLOAT_XXXX bits are clear, conformance to the
34 * base procedure-call standard is implied.
36 * The VDSO is built with -msoft-float, as with the rest of the ARM
37 * kernel, and uses no floating point arguments or results. The build
38 * process will produce a shared object that may or may not have the
39 * EF_ARM_ABI_FLOAT_SOFT flag set (it seems to depend on the binutils
40 * version; binutils starting with 2.24 appears to set it). The
41 * EF_ARM_ABI_FLOAT_HARD flag should definitely not be set, and this
42 * program will error out if it is.
44 * If the soft-float flag is set, this program clears it. That's all
61 #include <sys/types.h>
64 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
65 #define HOST_ORDER ELFDATA2LSB
66 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
67 #define HOST_ORDER ELFDATA2MSB
70 /* Some of the ELF constants we'd like to use were added to <elf.h>
71 * relatively recently.
73 #ifndef EF_ARM_EABI_VER5
74 #define EF_ARM_EABI_VER5 0x05000000
77 #ifndef EF_ARM_ABI_FLOAT_SOFT
78 #define EF_ARM_ABI_FLOAT_SOFT 0x200
81 #ifndef EF_ARM_ABI_FLOAT_HARD
82 #define EF_ARM_ABI_FLOAT_HARD 0x400
85 static const char *outfile;
87 static void cleanup(void)
89 if (error_message_count > 0 && outfile != NULL)
93 static Elf32_Word read_elf_word(Elf32_Word word, bool swap)
95 return swap ? bswap_32(word) : word;
98 static Elf32_Half read_elf_half(Elf32_Half half, bool swap)
100 return swap ? bswap_16(half) : half;
103 static void write_elf_word(Elf32_Word val, Elf32_Word *dst, bool swap)
105 *dst = swap ? bswap_32(val) : val;
108 int main(int argc, char **argv)
110 const Elf32_Ehdr *inhdr;
111 bool clear_soft_float;
124 error(EXIT_FAILURE, 0, "Usage: %s [infile] [outfile]", argv[0]);
129 infd = open(infile, O_RDONLY);
131 error(EXIT_FAILURE, errno, "Cannot open %s", infile);
133 if (fstat(infd, &stat) != 0)
134 error(EXIT_FAILURE, errno, "Failed stat for %s", infile);
136 inbuf = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, infd, 0);
137 if (inbuf == MAP_FAILED)
138 error(EXIT_FAILURE, errno, "Failed to map %s", infile);
144 if (memcmp(&inhdr->e_ident, ELFMAG, SELFMAG) != 0)
145 error(EXIT_FAILURE, 0, "Not an ELF file");
147 if (inhdr->e_ident[EI_CLASS] != ELFCLASS32)
148 error(EXIT_FAILURE, 0, "Unsupported ELF class");
150 swap = inhdr->e_ident[EI_DATA] != HOST_ORDER;
152 if (read_elf_half(inhdr->e_type, swap) != ET_DYN)
153 error(EXIT_FAILURE, 0, "Not a shared object");
155 if (read_elf_half(inhdr->e_machine, swap) != EM_ARM) {
156 error(EXIT_FAILURE, 0, "Unsupported architecture %#x",
160 e_flags = read_elf_word(inhdr->e_flags, swap);
162 if (EF_ARM_EABI_VERSION(e_flags) != EF_ARM_EABI_VER5) {
163 error(EXIT_FAILURE, 0, "Unsupported EABI version %#x",
164 EF_ARM_EABI_VERSION(e_flags));
167 if (e_flags & EF_ARM_ABI_FLOAT_HARD)
168 error(EXIT_FAILURE, 0,
169 "Unexpected hard-float flag set in e_flags");
171 clear_soft_float = !!(e_flags & EF_ARM_ABI_FLOAT_SOFT);
173 outfd = open(outfile, O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
175 error(EXIT_FAILURE, errno, "Cannot open %s", outfile);
177 if (ftruncate(outfd, stat.st_size) != 0)
178 error(EXIT_FAILURE, errno, "Cannot truncate %s", outfile);
180 outbuf = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
182 if (outbuf == MAP_FAILED)
183 error(EXIT_FAILURE, errno, "Failed to map %s", outfile);
187 memcpy(outbuf, inbuf, stat.st_size);
189 if (clear_soft_float) {
193 e_flags &= ~EF_ARM_ABI_FLOAT_SOFT;
194 write_elf_word(e_flags, &outhdr->e_flags, swap);
197 if (msync(outbuf, stat.st_size, MS_SYNC) != 0)
198 error(EXIT_FAILURE, errno, "Failed to sync %s", outfile);