1 /* Functions for CET/x86.
2 Copyright (C) 2017-2020 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "output.h"
25 #include "linux-common.h"
26
27 void
file_end_indicate_exec_stack_and_cet(void)28 file_end_indicate_exec_stack_and_cet (void)
29 {
30 file_end_indicate_exec_stack ();
31
32 if (flag_cf_protection == CF_NONE)
33 return;
34
35 unsigned int feature_1 = 0;
36
37 if (flag_cf_protection & CF_BRANCH)
38 /* GNU_PROPERTY_X86_FEATURE_1_IBT. */
39 feature_1 |= 0x1;
40
41 if (flag_cf_protection & CF_RETURN)
42 /* GNU_PROPERTY_X86_FEATURE_1_SHSTK. */
43 feature_1 |= 0x2;
44
45 if (feature_1)
46 {
47 int p2align = ptr_mode == SImode ? 2 : 3;
48
49 /* Generate GNU_PROPERTY_X86_FEATURE_1_XXX. */
50 switch_to_section (get_section (".note.gnu.property",
51 SECTION_NOTYPE, NULL));
52
53 ASM_OUTPUT_ALIGN (asm_out_file, p2align);
54 /* name length. */
55 fprintf (asm_out_file, ASM_LONG " 1f - 0f\n");
56 /* data length. */
57 fprintf (asm_out_file, ASM_LONG " 4f - 1f\n");
58 /* note type: NT_GNU_PROPERTY_TYPE_0. */
59 fprintf (asm_out_file, ASM_LONG " 5\n");
60 fprintf (asm_out_file, "0:\n");
61 /* vendor name: "GNU". */
62 fprintf (asm_out_file, STRING_ASM_OP " \"GNU\"\n");
63 fprintf (asm_out_file, "1:\n");
64 ASM_OUTPUT_ALIGN (asm_out_file, p2align);
65 /* pr_type: GNU_PROPERTY_X86_FEATURE_1_AND. */
66 fprintf (asm_out_file, ASM_LONG " 0xc0000002\n");
67 /* pr_datasz. */\
68 fprintf (asm_out_file, ASM_LONG " 3f - 2f\n");
69 fprintf (asm_out_file, "2:\n");
70 /* GNU_PROPERTY_X86_FEATURE_1_XXX. */
71 fprintf (asm_out_file, ASM_LONG " 0x%x\n", feature_1);
72 fprintf (asm_out_file, "3:\n");
73 ASM_OUTPUT_ALIGN (asm_out_file, p2align);
74 fprintf (asm_out_file, "4:\n");
75 }
76 }
77