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- diff -Nur linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c linux-4.14.44/arch/x86/entry/vdso/vdso2c.c
- --- linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c 2018-05-25 16:18:02.000000000 +0200
- +++ linux-4.14.44/arch/x86/entry/vdso/vdso2c.c 2018-05-31 02:09:00.000000000 +0200
- @@ -64,7 +64,15 @@
- #include <tools/le_byteshift.h>
-
- #include <linux/elf.h>
- +#ifdef __linux__
- #include <linux/types.h>
- +#else
- +typedef _Bool bool;
- +enum {
- + false = 0,
- + true = 1
- +};
- +#endif
-
- const char *outfilename;
-
- @@ -86,6 +94,7 @@
- sym_hvclock_page,
- };
-
- +
- struct vdso_sym {
- const char *name;
- bool export;
- diff -Nur linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c.orig linux-4.14.44/arch/x86/entry/vdso/vdso2c.c.orig
- --- linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c.orig 1970-01-01 01:00:00.000000000 +0100
- +++ linux-4.14.44/arch/x86/entry/vdso/vdso2c.c.orig 2018-05-25 16:18:02.000000000 +0200
- @@ -0,0 +1,259 @@
- +/*
- + * vdso2c - A vdso image preparation tool
- + * Copyright (c) 2014 Andy Lutomirski and others
- + * Licensed under the GPL v2
- + *
- + * 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're keep a section table for a few reasons:
- + *
- + * The Go runtime had a couple of bugs: it would read the section
- + * table to try to figure out how many dynamic symbols there were (it
- + * shouldn't have looked at the section table at all) and, if there
- + * were no SHT_SYNDYM section table entry, it would use an
- + * uninitialized value for the number of symbols. An empty DYNSYM
- + * table would work, but I see no reason not to write a valid one (and
- + * keep full performance for old Go programs). This hack is only
- + * needed on x86_64.
- + *
- + * The bug was introduced on 2012-08-31 by:
- + * https://code.google.com/p/go/source/detail?r=56ea40aac72b
- + * and was fixed on 2014-06-13 by:
- + * https://code.google.com/p/go/source/detail?r=fc1cd5e12595
- + *
- + * 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.
- + */
- +
- +#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/le_byteshift.h>
- +
- +#include <linux/elf.h>
- +#include <linux/types.h>
- +
- +const char *outfilename;
- +
- +/* Symbols that we need in vdso2c. */
- +enum {
- + sym_vvar_start,
- + sym_vvar_page,
- + sym_hpet_page,
- + sym_pvclock_page,
- + sym_hvclock_page,
- + sym_VDSO_FAKE_SECTION_TABLE_START,
- + sym_VDSO_FAKE_SECTION_TABLE_END,
- +};
- +
- +const int special_pages[] = {
- + sym_vvar_page,
- + sym_hpet_page,
- + sym_pvclock_page,
- + sym_hvclock_page,
- +};
- +
- +struct vdso_sym {
- + const char *name;
- + bool export;
- +};
- +
- +struct vdso_sym required_syms[] = {
- + [sym_vvar_start] = {"vvar_start", true},
- + [sym_vvar_page] = {"vvar_page", true},
- + [sym_hpet_page] = {"hpet_page", true},
- + [sym_pvclock_page] = {"pvclock_page", true},
- + [sym_hvclock_page] = {"hvclock_page", true},
- + [sym_VDSO_FAKE_SECTION_TABLE_START] = {
- + "VDSO_FAKE_SECTION_TABLE_START", false
- + },
- + [sym_VDSO_FAKE_SECTION_TABLE_END] = {
- + "VDSO_FAKE_SECTION_TABLE_END", false
- + },
- + {"VDSO32_NOTE_MASK", true},
- + {"__kernel_vsyscall", true},
- + {"__kernel_sigreturn", true},
- + {"__kernel_rt_sigreturn", true},
- + {"int80_landing_pad", true},
- +};
- +
- +__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 little-endian reads and writes
- + */
- +#define GLE(x, bits, ifnot) \
- + __builtin_choose_expr( \
- + (sizeof(*(x)) == bits/8), \
- + (__typeof__(*(x)))get_unaligned_le##bits(x), ifnot)
- +
- +extern void bad_get_le(void);
- +#define LAST_GLE(x) \
- + __builtin_choose_expr(sizeof(*(x)) == 1, *(x), bad_get_le())
- +
- +#define GET_LE(x) \
- + GLE(x, 64, GLE(x, 32, GLE(x, 16, LAST_GLE(x))))
- +
- +#define PLE(x, val, bits, ifnot) \
- + __builtin_choose_expr( \
- + (sizeof(*(x)) == bits/8), \
- + put_unaligned_le##bits((val), (x)), ifnot)
- +
- +extern void bad_put_le(void);
- +#define LAST_PLE(x, val) \
- + __builtin_choose_expr(sizeof(*(x)) == 1, *(x) = (val), bad_put_le())
- +
- +#define PUT_LE(x, val) \
- + PLE(x, val, 64, PLE(x, val, 32, PLE(x, val, 16, LAST_PLE(x, val))))
- +
- +
- +#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))
- +
- +#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;
- +}
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