tools/testing/selftests/x86/check_initial_reg_state.c

   1 /*
   2  * check_initial_reg_state.c - check that execve sets the correct state
   3  * Copyright (c) 2014-2016 Andrew Lutomirski
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #define _GNU_SOURCE
  16
  17 #include <stdio.h>
  18
  19 unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
  20 unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
  21
  22 asm (
  23         ".pushsection .text\n\t"
  24         ".type real_start, @function\n\t"
  25         ".global real_start\n\t"
  26         "real_start:\n\t"
  27 #ifdef __x86_64__
  28         "mov %rax, ax\n\t"
  29         "mov %rbx, bx\n\t"
  30         "mov %rcx, cx\n\t"
  31         "mov %rdx, dx\n\t"
  32         "mov %rsi, si\n\t"
  33         "mov %rdi, di\n\t"
  34         "mov %rbp, bp\n\t"
  35         "mov %rsp, sp\n\t"
  36         "mov %r8, r8\n\t"
  37         "mov %r9, r9\n\t"
  38         "mov %r10, r10\n\t"
  39         "mov %r11, r11\n\t"
  40         "mov %r12, r12\n\t"
  41         "mov %r13, r13\n\t"
  42         "mov %r14, r14\n\t"
  43         "mov %r15, r15\n\t"
  44         "pushfq\n\t"
  45         "popq flags\n\t"
  46 #else
  47         "mov %eax, ax\n\t"
  48         "mov %ebx, bx\n\t"
  49         "mov %ecx, cx\n\t"
  50         "mov %edx, dx\n\t"
  51         "mov %esi, si\n\t"
  52         "mov %edi, di\n\t"
  53         "mov %ebp, bp\n\t"
  54         "mov %esp, sp\n\t"
  55         "pushfl\n\t"
  56         "popl flags\n\t"
  57 #endif
  58         "jmp _start\n\t"
  59         ".size real_start, . - real_start\n\t"
  60         ".popsection");
  61
  62 int main()
  63 {
  64         int nerrs = 0;
  65
  66         if (sp == 0) {
  67                 printf("[FAIL]\tTest was built incorrectly\n");
  68                 return 1;
  69         }
  70
  71         if (ax || bx || cx || dx || si || di || bp
  72 #ifdef __x86_64__
  73             || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15
  74 #endif
  75                 ) {
  76                 printf("[FAIL]\tAll GPRs except SP should be 0\n");
  77 #define SHOW(x) printf("\t" #x " = 0x%lx\n", x);
  78                 SHOW(ax);
  79                 SHOW(bx);
  80                 SHOW(cx);
  81                 SHOW(dx);
  82                 SHOW(si);
  83                 SHOW(di);
  84                 SHOW(bp);
  85                 SHOW(sp);
  86 #ifdef __x86_64__
  87                 SHOW(r8);
  88                 SHOW(r9);
  89                 SHOW(r10);
  90                 SHOW(r11);
  91                 SHOW(r12);
  92                 SHOW(r13);
  93                 SHOW(r14);
  94                 SHOW(r15);
  95 #endif
  96                 nerrs++;
  97         } else {
  98                 printf("[OK]\tAll GPRs except SP are 0\n");
  99         }
 100
 101         if (flags != 0x202) {
 102                 printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);
 103                 nerrs++;
 104         } else {
 105                 printf("[OK]\tFLAGS is 0x202\n");
 106         }
 107
 108         return nerrs ? 1 : 0;
 109 }