lib/csu/i386/reloc.c

   1 /*-
   2  * Copyright (c) 2018 The FreeBSD Foundation
   3  *
   4  * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
   5  * under sponsorship from the FreeBSD Foundation.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  */
  25
  26 #include <sys/cdefs.h>
  27 __FBSDID("$FreeBSD$");
  28
  29 #include <machine/specialreg.h>
  30 #include <machine/cpufunc.h>
  31
  32 static void
  33 crt1_handle_rel(const Elf_Rel *r)
  34 {
  35         Elf_Addr *where, target;
  36         u_int cpuid_supported, p[4];
  37         uint32_t cpu_feature, cpu_feature2;
  38         uint32_t cpu_stdext_feature, cpu_stdext_feature2;
  39
  40         __asm __volatile(
  41             "   pushfl\n"
  42             "   popl    %%eax\n"
  43             "   movl    %%eax,%%ecx\n"
  44             "   xorl    $0x200000,%%eax\n"
  45             "   pushl   %%eax\n"
  46             "   popfl\n"
  47             "   pushfl\n"
  48             "   popl    %%eax\n"
  49             "   xorl    %%eax,%%ecx\n"
  50             "   je      1f\n"
  51             "   movl    $1,%0\n"
  52             "   jmp     2f\n"
  53             "1: movl    $0,%0\n"
  54             "2:\n"
  55             : "=r" (cpuid_supported) : : "eax", "ecx", "cc");
  56         if (cpuid_supported) {
  57                 do_cpuid(1, p);
  58                 cpu_feature = p[3];
  59                 cpu_feature2 = p[2];
  60                 do_cpuid(0, p);
  61                 if (p[0] >= 7) {
  62                         cpuid_count(7, 0, p);
  63                         cpu_stdext_feature = p[1];
  64                         cpu_stdext_feature2 = p[2];
  65                 } else {
  66                         cpu_stdext_feature = 0;
  67                         cpu_stdext_feature2 = 0;
  68                 }
  69         } else {
  70                 cpu_feature = 0;
  71                 cpu_feature2 = 0;
  72                 cpu_stdext_feature = 0;
  73                 cpu_stdext_feature2 = 0;
  74         }
  75
  76         switch (ELF_R_TYPE(r->r_info)) {
  77         case R_386_IRELATIVE:
  78                 where = (Elf_Addr *)r->r_offset;
  79                 target = ((Elf_Addr (*)(uint32_t, uint32_t, uint32_t,
  80                     uint32_t))*where)(cpu_feature, cpu_feature2,
  81                     cpu_stdext_feature, cpu_stdext_feature2);
  82                 *where = target;
  83                 break;
  84         }
  85 }