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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/sparc/vdso/vdso2c.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/sparc/vdso/vdso2c.c')
-rw-r--r-- | arch/sparc/vdso/vdso2c.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/arch/sparc/vdso/vdso2c.c b/arch/sparc/vdso/vdso2c.c new file mode 100644 index 0000000000..dc81240aab --- /dev/null +++ b/arch/sparc/vdso/vdso2c.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * vdso2c - A vdso image preparation tool + * Copyright (c) 2014 Andy Lutomirski and others + * + * vdso2c requires stripped and unstripped input. It would be trivial + * to fully strip the input in here, but, for reasons described below, + * we need to write a section table. Doing this is more or less + * equivalent to dropping all non-allocatable sections, but it's + * easier to let objcopy handle that instead of doing it ourselves. + * If we ever need to do something fancier than what objcopy provides, + * it would be straightforward to add here. + * + * We keep a section table for a few reasons: + * + * Binutils has issues debugging the vDSO: it reads the section table to + * find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which + * would break build-id if we removed the section table. Binutils + * also requires that shstrndx != 0. See: + * https://sourceware.org/bugzilla/show_bug.cgi?id=17064 + * + * elfutils might not look for PT_NOTE if there is a section table at + * all. I don't know whether this matters for any practical purpose. + * + * For simplicity, rather than hacking up a partial section table, we + * just write a mostly complete one. We omit non-dynamic symbols, + * though, since they're rather large. + * + * Once binutils gets fixed, we might be able to drop this for all but + * the 64-bit vdso, since build-id only works in kernel RPMs, and + * systems that update to new enough kernel RPMs will likely update + * binutils in sync. build-id has never worked for home-built kernel + * RPMs without manual symlinking, and I suspect that no one ever does + * that. + */ + +/* + * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved. + */ + +#include <inttypes.h> +#include <stdint.h> +#include <unistd.h> +#include <stdarg.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <fcntl.h> +#include <err.h> + +#include <sys/mman.h> +#include <sys/types.h> +#include <tools/be_byteshift.h> + +#include <linux/elf.h> +#include <linux/types.h> +#include <linux/kernel.h> + +const char *outfilename; + +/* Symbols that we need in vdso2c. */ +enum { + sym_vvar_start, + sym_VDSO_FAKE_SECTION_TABLE_START, + sym_VDSO_FAKE_SECTION_TABLE_END, +}; + +struct vdso_sym { + const char *name; + int export; +}; + +struct vdso_sym required_syms[] = { + [sym_vvar_start] = {"vvar_start", 1}, + [sym_VDSO_FAKE_SECTION_TABLE_START] = { + "VDSO_FAKE_SECTION_TABLE_START", 0 + }, + [sym_VDSO_FAKE_SECTION_TABLE_END] = { + "VDSO_FAKE_SECTION_TABLE_END", 0 + }, +}; + +__attribute__((format(printf, 1, 2))) __attribute__((noreturn)) +static void fail(const char *format, ...) +{ + va_list ap; + + va_start(ap, format); + fprintf(stderr, "Error: "); + vfprintf(stderr, format, ap); + if (outfilename) + unlink(outfilename); + exit(1); + va_end(ap); +} + +/* + * Evil macros for big-endian reads and writes + */ +#define GBE(x, bits, ifnot) \ + __builtin_choose_expr( \ + (sizeof(*(x)) == bits/8), \ + (__typeof__(*(x)))get_unaligned_be##bits(x), ifnot) + +#define LAST_GBE(x) \ + __builtin_choose_expr(sizeof(*(x)) == 1, *(x), (void)(0)) + +#define GET_BE(x) \ + GBE(x, 64, GBE(x, 32, GBE(x, 16, LAST_GBE(x)))) + +#define PBE(x, val, bits, ifnot) \ + __builtin_choose_expr( \ + (sizeof(*(x)) == bits/8), \ + put_unaligned_be##bits((val), (x)), ifnot) + +#define LAST_PBE(x, val) \ + __builtin_choose_expr(sizeof(*(x)) == 1, *(x) = (val), (void)(0)) + +#define PUT_BE(x, val) \ + PBE(x, val, 64, PBE(x, val, 32, PBE(x, val, 16, LAST_PBE(x, val)))) + +#define NSYMS ARRAY_SIZE(required_syms) + +#define BITSFUNC3(name, bits, suffix) name##bits##suffix +#define BITSFUNC2(name, bits, suffix) BITSFUNC3(name, bits, suffix) +#define BITSFUNC(name) BITSFUNC2(name, ELF_BITS, ) + +#define INT_BITS BITSFUNC2(int, ELF_BITS, _t) + +#define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x +#define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) +#define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) + +#define ELF_BITS 64 +#include "vdso2c.h" +#undef ELF_BITS + +#define ELF_BITS 32 +#include "vdso2c.h" +#undef ELF_BITS + +static void go(void *raw_addr, size_t raw_len, + void *stripped_addr, size_t stripped_len, + FILE *outfile, const char *name) +{ + Elf64_Ehdr *hdr = (Elf64_Ehdr *)raw_addr; + + if (hdr->e_ident[EI_CLASS] == ELFCLASS64) { + go64(raw_addr, raw_len, stripped_addr, stripped_len, + outfile, name); + } else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) { + go32(raw_addr, raw_len, stripped_addr, stripped_len, + outfile, name); + } else { + fail("unknown ELF class\n"); + } +} + +static void map_input(const char *name, void **addr, size_t *len, int prot) +{ + off_t tmp_len; + + int fd = open(name, O_RDONLY); + + if (fd == -1) + err(1, "%s", name); + + tmp_len = lseek(fd, 0, SEEK_END); + if (tmp_len == (off_t)-1) + err(1, "lseek"); + *len = (size_t)tmp_len; + + *addr = mmap(NULL, tmp_len, prot, MAP_PRIVATE, fd, 0); + if (*addr == MAP_FAILED) + err(1, "mmap"); + + close(fd); +} + +int main(int argc, char **argv) +{ + size_t raw_len, stripped_len; + void *raw_addr, *stripped_addr; + FILE *outfile; + char *name, *tmp; + int namelen; + + if (argc != 4) { + printf("Usage: vdso2c RAW_INPUT STRIPPED_INPUT OUTPUT\n"); + return 1; + } + + /* + * Figure out the struct name. If we're writing to a .so file, + * generate raw output insted. + */ + name = strdup(argv[3]); + namelen = strlen(name); + if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) { + name = NULL; + } else { + tmp = strrchr(name, '/'); + if (tmp) + name = tmp + 1; + tmp = strchr(name, '.'); + if (tmp) + *tmp = '\0'; + for (tmp = name; *tmp; tmp++) + if (*tmp == '-') + *tmp = '_'; + } + + map_input(argv[1], &raw_addr, &raw_len, PROT_READ); + map_input(argv[2], &stripped_addr, &stripped_len, PROT_READ); + + outfilename = argv[3]; + outfile = fopen(outfilename, "w"); + if (!outfile) + err(1, "%s", argv[2]); + + go(raw_addr, raw_len, stripped_addr, stripped_len, outfile, name); + + munmap(raw_addr, raw_len); + munmap(stripped_addr, stripped_len); + fclose(outfile); + + return 0; +} |