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 }
102
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