tools/testing/selftests/x86/check_initial_reg_state.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * check_initial_reg_state.c - check that execve sets the correct state
   4  * Copyright (c) 2014-2016 Andrew Lutomirski
   5  */
   6
   7 #define _GNU_SOURCE
   8
   9 #include <stdio.h>
  10
  11 unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
  12 unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
  13
  14 asm (
  15         ".pushsection .text\n\t"
  16         ".type real_start, @function\n\t"
  17         ".global real_start\n\t"
  18         "real_start:\n\t"
  19 #ifdef __x86_64__
  20         "mov %rax, ax\n\t"
  21         "mov %rbx, bx\n\t"
  22         "mov %rcx, cx\n\t"
  23         "mov %rdx, dx\n\t"
  24         "mov %rsi, si\n\t"
  25         "mov %rdi, di\n\t"
  26         "mov %rbp, bp\n\t"
  27         "mov %rsp, sp\n\t"
  28         "mov %r8, r8\n\t"
  29         "mov %r9, r9\n\t"
  30         "mov %r10, r10\n\t"
  31         "mov %r11, r11\n\t"
  32         "mov %r12, r12\n\t"
  33         "mov %r13, r13\n\t"
  34         "mov %r14, r14\n\t"
  35         "mov %r15, r15\n\t"
  36         "pushfq\n\t"
  37         "popq flags\n\t"
  38 #else
  39         "mov %eax, ax\n\t"
  40         "mov %ebx, bx\n\t"
  41         "mov %ecx, cx\n\t"
  42         "mov %edx, dx\n\t"
  43         "mov %esi, si\n\t"
  44         "mov %edi, di\n\t"
  45         "mov %ebp, bp\n\t"
  46         "mov %esp, sp\n\t"
  47         "pushfl\n\t"
  48         "popl flags\n\t"
  49 #endif
  50         "jmp _start\n\t"
  51         ".size real_start, . - real_start\n\t"
  52         ".popsection");
  53
  54 int main()
  55 {
  56         int nerrs = 0;
  57
  58         if (sp == 0) {
  59                 printf("[FAIL]\tTest was built incorrectly\n");
  60                 return 1;
  61         }
  62
  63         if (ax || bx || cx || dx || si || di || bp
  64 #ifdef __x86_64__
  65             || r8 || r9 || r10 || r11 || r12 || r13 || r14 || r15
  66 #endif
  67                 ) {
  68                 printf("[FAIL]\tAll GPRs except SP should be 0\n");
  69 #define SHOW(x) printf("\t" #x " = 0x%lx\n", x);
  70                 SHOW(ax);
  71                 SHOW(bx);
  72                 SHOW(cx);
  73                 SHOW(dx);
  74                 SHOW(si);
  75                 SHOW(di);
  76                 SHOW(bp);
  77                 SHOW(sp);
  78 #ifdef __x86_64__
  79                 SHOW(r8);
  80                 SHOW(r9);
  81                 SHOW(r10);
  82                 SHOW(r11);
  83                 SHOW(r12);
  84                 SHOW(r13);
  85                 SHOW(r14);
  86                 SHOW(r15);
  87 #endif
  88                 nerrs++;
  89         } else {
  90                 printf("[OK]\tAll GPRs except SP are 0\n");
  91         }
  92
  93         if (flags != 0x202) {
  94                 printf("[FAIL]\tFLAGS is 0x%lx, but it should be 0x202\n", flags);
  95                 nerrs++;
  96         } else {
  97                 printf("[OK]\tFLAGS is 0x202\n");
  98         }
  99
 100         return nerrs ? 1 : 0;
 101 }