1*2b72c9e3SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
28512287aSNathan Lynch /*
38512287aSNathan Lynch * Copyright 2015 Mentor Graphics Corporation.
48512287aSNathan Lynch *
58512287aSNathan Lynch * vdsomunge - Host program which produces a shared object
68512287aSNathan Lynch * architecturally specified to be usable by both soft- and hard-float
78512287aSNathan Lynch * programs.
88512287aSNathan Lynch *
98512287aSNathan Lynch * The Procedure Call Standard for the ARM Architecture (ARM IHI
108512287aSNathan Lynch * 0042E) says:
118512287aSNathan Lynch *
128512287aSNathan Lynch * 6.4.1 VFP and Base Standard Compatibility
138512287aSNathan Lynch *
148512287aSNathan Lynch * Code compiled for the VFP calling standard is compatible with
158512287aSNathan Lynch * the base standard (and vice-versa) if no floating-point or
168512287aSNathan Lynch * containerized vector arguments or results are used.
178512287aSNathan Lynch *
188512287aSNathan Lynch * And ELF for the ARM Architecture (ARM IHI 0044E) (Table 4-2) says:
198512287aSNathan Lynch *
208512287aSNathan Lynch * If both EF_ARM_ABI_FLOAT_XXXX bits are clear, conformance to the
218512287aSNathan Lynch * base procedure-call standard is implied.
228512287aSNathan Lynch *
238512287aSNathan Lynch * The VDSO is built with -msoft-float, as with the rest of the ARM
248512287aSNathan Lynch * kernel, and uses no floating point arguments or results. The build
258512287aSNathan Lynch * process will produce a shared object that may or may not have the
268512287aSNathan Lynch * EF_ARM_ABI_FLOAT_SOFT flag set (it seems to depend on the binutils
278512287aSNathan Lynch * version; binutils starting with 2.24 appears to set it). The
288512287aSNathan Lynch * EF_ARM_ABI_FLOAT_HARD flag should definitely not be set, and this
298512287aSNathan Lynch * program will error out if it is.
308512287aSNathan Lynch *
318512287aSNathan Lynch * If the soft-float flag is set, this program clears it. That's all
328512287aSNathan Lynch * it does.
338512287aSNathan Lynch */
348512287aSNathan Lynch
358512287aSNathan Lynch #include <elf.h>
368512287aSNathan Lynch #include <errno.h>
378512287aSNathan Lynch #include <fcntl.h>
3813ee9fdbSSzabolcs Nagy #include <stdarg.h>
398512287aSNathan Lynch #include <stdbool.h>
408512287aSNathan Lynch #include <stdio.h>
418512287aSNathan Lynch #include <stdlib.h>
428512287aSNathan Lynch #include <string.h>
438512287aSNathan Lynch #include <sys/mman.h>
448512287aSNathan Lynch #include <sys/stat.h>
458512287aSNathan Lynch #include <sys/types.h>
468512287aSNathan Lynch #include <unistd.h>
478512287aSNathan Lynch
488a603f91SH. Nikolaus Schaller #define swab16(x) \
498a603f91SH. Nikolaus Schaller ((((x) & 0x00ff) << 8) | \
508a603f91SH. Nikolaus Schaller (((x) & 0xff00) >> 8))
518a603f91SH. Nikolaus Schaller
528a603f91SH. Nikolaus Schaller #define swab32(x) \
538a603f91SH. Nikolaus Schaller ((((x) & 0x000000ff) << 24) | \
548a603f91SH. Nikolaus Schaller (((x) & 0x0000ff00) << 8) | \
558a603f91SH. Nikolaus Schaller (((x) & 0x00ff0000) >> 8) | \
5638850d78SH. Nikolaus Schaller (((x) & 0xff000000) >> 24))
578a603f91SH. Nikolaus Schaller
588512287aSNathan Lynch #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
598512287aSNathan Lynch #define HOST_ORDER ELFDATA2LSB
608512287aSNathan Lynch #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
618512287aSNathan Lynch #define HOST_ORDER ELFDATA2MSB
628512287aSNathan Lynch #endif
638512287aSNathan Lynch
648512287aSNathan Lynch /* Some of the ELF constants we'd like to use were added to <elf.h>
658512287aSNathan Lynch * relatively recently.
668512287aSNathan Lynch */
678512287aSNathan Lynch #ifndef EF_ARM_EABI_VER5
688512287aSNathan Lynch #define EF_ARM_EABI_VER5 0x05000000
698512287aSNathan Lynch #endif
708512287aSNathan Lynch
718512287aSNathan Lynch #ifndef EF_ARM_ABI_FLOAT_SOFT
728512287aSNathan Lynch #define EF_ARM_ABI_FLOAT_SOFT 0x200
738512287aSNathan Lynch #endif
748512287aSNathan Lynch
758512287aSNathan Lynch #ifndef EF_ARM_ABI_FLOAT_HARD
768512287aSNathan Lynch #define EF_ARM_ABI_FLOAT_HARD 0x400
778512287aSNathan Lynch #endif
788512287aSNathan Lynch
7913ee9fdbSSzabolcs Nagy static int failed;
8013ee9fdbSSzabolcs Nagy static const char *argv0;
818512287aSNathan Lynch static const char *outfile;
828512287aSNathan Lynch
fail(const char * fmt,...)8313ee9fdbSSzabolcs Nagy static void fail(const char *fmt, ...)
8413ee9fdbSSzabolcs Nagy {
8513ee9fdbSSzabolcs Nagy va_list ap;
8613ee9fdbSSzabolcs Nagy
8713ee9fdbSSzabolcs Nagy failed = 1;
8813ee9fdbSSzabolcs Nagy fprintf(stderr, "%s: ", argv0);
8913ee9fdbSSzabolcs Nagy va_start(ap, fmt);
9013ee9fdbSSzabolcs Nagy vfprintf(stderr, fmt, ap);
9113ee9fdbSSzabolcs Nagy va_end(ap);
9213ee9fdbSSzabolcs Nagy exit(EXIT_FAILURE);
9313ee9fdbSSzabolcs Nagy }
9413ee9fdbSSzabolcs Nagy
cleanup(void)958512287aSNathan Lynch static void cleanup(void)
968512287aSNathan Lynch {
9713ee9fdbSSzabolcs Nagy if (failed && outfile != NULL)
988512287aSNathan Lynch unlink(outfile);
998512287aSNathan Lynch }
1008512287aSNathan Lynch
read_elf_word(Elf32_Word word,bool swap)1018512287aSNathan Lynch static Elf32_Word read_elf_word(Elf32_Word word, bool swap)
1028512287aSNathan Lynch {
1038a603f91SH. Nikolaus Schaller return swap ? swab32(word) : word;
1048512287aSNathan Lynch }
1058512287aSNathan Lynch
read_elf_half(Elf32_Half half,bool swap)1068512287aSNathan Lynch static Elf32_Half read_elf_half(Elf32_Half half, bool swap)
1078512287aSNathan Lynch {
1088a603f91SH. Nikolaus Schaller return swap ? swab16(half) : half;
1098512287aSNathan Lynch }
1108512287aSNathan Lynch
write_elf_word(Elf32_Word val,Elf32_Word * dst,bool swap)1118512287aSNathan Lynch static void write_elf_word(Elf32_Word val, Elf32_Word *dst, bool swap)
1128512287aSNathan Lynch {
1138a603f91SH. Nikolaus Schaller *dst = swap ? swab32(val) : val;
1148512287aSNathan Lynch }
1158512287aSNathan Lynch
main(int argc,char ** argv)1168512287aSNathan Lynch int main(int argc, char **argv)
1178512287aSNathan Lynch {
1188512287aSNathan Lynch const Elf32_Ehdr *inhdr;
1198512287aSNathan Lynch bool clear_soft_float;
1208512287aSNathan Lynch const char *infile;
1218512287aSNathan Lynch Elf32_Word e_flags;
1228512287aSNathan Lynch const void *inbuf;
1238512287aSNathan Lynch struct stat stat;
1248512287aSNathan Lynch void *outbuf;
1258512287aSNathan Lynch bool swap;
1268512287aSNathan Lynch int outfd;
1278512287aSNathan Lynch int infd;
1288512287aSNathan Lynch
1298512287aSNathan Lynch atexit(cleanup);
13013ee9fdbSSzabolcs Nagy argv0 = argv[0];
1318512287aSNathan Lynch
1328512287aSNathan Lynch if (argc != 3)
13313ee9fdbSSzabolcs Nagy fail("Usage: %s [infile] [outfile]\n", argv[0]);
1348512287aSNathan Lynch
1358512287aSNathan Lynch infile = argv[1];
1368512287aSNathan Lynch outfile = argv[2];
1378512287aSNathan Lynch
1388512287aSNathan Lynch infd = open(infile, O_RDONLY);
1398512287aSNathan Lynch if (infd < 0)
14013ee9fdbSSzabolcs Nagy fail("Cannot open %s: %s\n", infile, strerror(errno));
1418512287aSNathan Lynch
1428512287aSNathan Lynch if (fstat(infd, &stat) != 0)
14313ee9fdbSSzabolcs Nagy fail("Failed stat for %s: %s\n", infile, strerror(errno));
1448512287aSNathan Lynch
1458512287aSNathan Lynch inbuf = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, infd, 0);
1468512287aSNathan Lynch if (inbuf == MAP_FAILED)
14713ee9fdbSSzabolcs Nagy fail("Failed to map %s: %s\n", infile, strerror(errno));
1488512287aSNathan Lynch
1498512287aSNathan Lynch close(infd);
1508512287aSNathan Lynch
1518512287aSNathan Lynch inhdr = inbuf;
1528512287aSNathan Lynch
1538512287aSNathan Lynch if (memcmp(&inhdr->e_ident, ELFMAG, SELFMAG) != 0)
15413ee9fdbSSzabolcs Nagy fail("Not an ELF file\n");
1558512287aSNathan Lynch
1568512287aSNathan Lynch if (inhdr->e_ident[EI_CLASS] != ELFCLASS32)
15713ee9fdbSSzabolcs Nagy fail("Unsupported ELF class\n");
1588512287aSNathan Lynch
1598512287aSNathan Lynch swap = inhdr->e_ident[EI_DATA] != HOST_ORDER;
1608512287aSNathan Lynch
1618512287aSNathan Lynch if (read_elf_half(inhdr->e_type, swap) != ET_DYN)
16213ee9fdbSSzabolcs Nagy fail("Not a shared object\n");
1638512287aSNathan Lynch
16413ee9fdbSSzabolcs Nagy if (read_elf_half(inhdr->e_machine, swap) != EM_ARM)
16513ee9fdbSSzabolcs Nagy fail("Unsupported architecture %#x\n", inhdr->e_machine);
1668512287aSNathan Lynch
1678512287aSNathan Lynch e_flags = read_elf_word(inhdr->e_flags, swap);
1688512287aSNathan Lynch
1698512287aSNathan Lynch if (EF_ARM_EABI_VERSION(e_flags) != EF_ARM_EABI_VER5) {
17013ee9fdbSSzabolcs Nagy fail("Unsupported EABI version %#x\n",
1718512287aSNathan Lynch EF_ARM_EABI_VERSION(e_flags));
1728512287aSNathan Lynch }
1738512287aSNathan Lynch
1748512287aSNathan Lynch if (e_flags & EF_ARM_ABI_FLOAT_HARD)
17513ee9fdbSSzabolcs Nagy fail("Unexpected hard-float flag set in e_flags\n");
1768512287aSNathan Lynch
1778512287aSNathan Lynch clear_soft_float = !!(e_flags & EF_ARM_ABI_FLOAT_SOFT);
1788512287aSNathan Lynch
1798512287aSNathan Lynch outfd = open(outfile, O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
1808512287aSNathan Lynch if (outfd < 0)
18113ee9fdbSSzabolcs Nagy fail("Cannot open %s: %s\n", outfile, strerror(errno));
1828512287aSNathan Lynch
1838512287aSNathan Lynch if (ftruncate(outfd, stat.st_size) != 0)
18413ee9fdbSSzabolcs Nagy fail("Cannot truncate %s: %s\n", outfile, strerror(errno));
1858512287aSNathan Lynch
1868512287aSNathan Lynch outbuf = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
1878512287aSNathan Lynch outfd, 0);
1888512287aSNathan Lynch if (outbuf == MAP_FAILED)
18913ee9fdbSSzabolcs Nagy fail("Failed to map %s: %s\n", outfile, strerror(errno));
1908512287aSNathan Lynch
1918512287aSNathan Lynch close(outfd);
1928512287aSNathan Lynch
1938512287aSNathan Lynch memcpy(outbuf, inbuf, stat.st_size);
1948512287aSNathan Lynch
1958512287aSNathan Lynch if (clear_soft_float) {
1968512287aSNathan Lynch Elf32_Ehdr *outhdr;
1978512287aSNathan Lynch
1988512287aSNathan Lynch outhdr = outbuf;
1998512287aSNathan Lynch e_flags &= ~EF_ARM_ABI_FLOAT_SOFT;
2008512287aSNathan Lynch write_elf_word(e_flags, &outhdr->e_flags, swap);
2018512287aSNathan Lynch }
2028512287aSNathan Lynch
2038512287aSNathan Lynch if (msync(outbuf, stat.st_size, MS_SYNC) != 0)
20413ee9fdbSSzabolcs Nagy fail("Failed to sync %s: %s\n", outfile, strerror(errno));
2058512287aSNathan Lynch
2068512287aSNathan Lynch return EXIT_SUCCESS;
2078512287aSNathan Lynch }
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