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18d0a6fd22
This unifies the vdso mapping code and teaches it how to map special pages at addresses corresponding to symbols in the vdso image. The new code is used for all vdso variants, but so far only the 32-bit variants use the new vvar page position. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/b6d7858ad7b5ac3fd3c29cab6d6d769bc45d195e.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
156 lines
2.9 KiB
C
156 lines
2.9 KiB
C
#include <inttypes.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <err.h>
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <linux/elf.h>
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#include <linux/types.h>
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/* Symbols that we need in vdso2c. */
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enum {
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sym_vvar_page,
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sym_hpet_page,
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sym_end_mapping,
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};
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const int special_pages[] = {
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sym_vvar_page,
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sym_hpet_page,
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};
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char const * const required_syms[] = {
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[sym_vvar_page] = "vvar_page",
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[sym_hpet_page] = "hpet_page",
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[sym_end_mapping] = "end_mapping",
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"VDSO32_NOTE_MASK",
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"VDSO32_SYSENTER_RETURN",
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"__kernel_vsyscall",
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"__kernel_sigreturn",
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"__kernel_rt_sigreturn",
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};
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__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
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static void fail(const char *format, ...)
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{
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va_list ap;
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va_start(ap, format);
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fprintf(stderr, "Error: ");
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vfprintf(stderr, format, ap);
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exit(1);
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va_end(ap);
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}
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#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))
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#define BITS 64
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#define GOFUNC go64
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#define Elf_Ehdr Elf64_Ehdr
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#define Elf_Shdr Elf64_Shdr
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#define Elf_Phdr Elf64_Phdr
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#define Elf_Sym Elf64_Sym
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#define Elf_Dyn Elf64_Dyn
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#include "vdso2c.h"
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#undef BITS
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#undef GOFUNC
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#undef Elf_Ehdr
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#undef Elf_Shdr
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#undef Elf_Phdr
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#undef Elf_Sym
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#undef Elf_Dyn
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#define BITS 32
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#define GOFUNC go32
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#define Elf_Ehdr Elf32_Ehdr
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#define Elf_Shdr Elf32_Shdr
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#define Elf_Phdr Elf32_Phdr
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#define Elf_Sym Elf32_Sym
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#define Elf_Dyn Elf32_Dyn
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#include "vdso2c.h"
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#undef BITS
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#undef GOFUNC
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#undef Elf_Ehdr
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#undef Elf_Shdr
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#undef Elf_Phdr
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#undef Elf_Sym
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#undef Elf_Dyn
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static int go(void *addr, size_t len, FILE *outfile, const char *name)
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{
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Elf64_Ehdr *hdr = (Elf64_Ehdr *)addr;
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if (hdr->e_ident[EI_CLASS] == ELFCLASS64) {
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return go64(addr, len, outfile, name);
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} else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) {
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return go32(addr, len, outfile, name);
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} else {
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fprintf(stderr, "Error: unknown ELF class\n");
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return 1;
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}
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}
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int main(int argc, char **argv)
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{
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int fd;
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off_t len;
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void *addr;
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FILE *outfile;
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int ret;
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char *name, *tmp;
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int namelen;
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if (argc != 3) {
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printf("Usage: vdso2c INPUT OUTPUT\n");
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return 1;
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}
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/*
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* Figure out the struct name. If we're writing to a .so file,
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* generate raw output insted.
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*/
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name = strdup(argv[2]);
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namelen = strlen(name);
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if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) {
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name = NULL;
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} else {
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tmp = strrchr(name, '/');
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if (tmp)
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name = tmp + 1;
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tmp = strchr(name, '.');
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if (tmp)
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*tmp = '\0';
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for (tmp = name; *tmp; tmp++)
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if (*tmp == '-')
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*tmp = '_';
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}
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fd = open(argv[1], O_RDONLY);
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if (fd == -1)
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err(1, "%s", argv[1]);
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len = lseek(fd, 0, SEEK_END);
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if (len == (off_t)-1)
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err(1, "lseek");
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addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (addr == MAP_FAILED)
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err(1, "mmap");
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outfile = fopen(argv[2], "w");
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if (!outfile)
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err(1, "%s", argv[2]);
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ret = go(addr, (size_t)len, outfile, name);
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munmap(addr, len);
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fclose(outfile);
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return ret;
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}
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