1 | /* Copyright (C) 2001-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ |
17 | |
18 | /* This file contains a bit of information about the stack allocation |
19 | of the processor. */ |
20 | |
21 | #ifndef _STACKINFO_H |
22 | #define _STACKINFO_H 1 |
23 | |
24 | #include <elf.h> |
25 | |
26 | /* On x86_64 the stack grows down. */ |
27 | #define _STACK_GROWS_DOWN 1 |
28 | |
29 | /* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is |
30 | * present, but it is presumed absent. */ |
31 | #define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X) |
32 | |
33 | /* Access to the stack pointer. The macros are used in alloca_account |
34 | for which they need to act as barriers as well, hence the additional |
35 | (unnecessary) parameters. */ |
36 | #define stackinfo_get_sp() \ |
37 | ({ void *p__; asm volatile ("mov %%" RSP_LP ", %0" : "=r" (p__)); p__; }) |
38 | #define stackinfo_sub_sp(ptr) \ |
39 | ({ ptrdiff_t d__; \ |
40 | asm volatile ("sub %%" RSP_LP " , %0" : "=r" (d__) : "0" (ptr)); \ |
41 | d__; }) |
42 | |
43 | #endif /* stackinfo.h */ |
44 | |