LXR linux/tools/testing/selftests/x86/check_initial_reg

   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
  11unsigned long ax, bx, cx, dx, si, di, bp, sp, flags;
  12unsigned long r8, r9, r10, r11, r12, r13, r14, r15;
  13
  14asm (
  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
  54int 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}
 102