| 1 | /* Copyright (C) 2001-2022 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | /* This file contains a bit of information about the stack allocation |
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| 19 | of the processor. */ |
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| 20 | |
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| 21 | #ifndef _STACKINFO_H |
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| 22 | #define _STACKINFO_H 1 |
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| 23 | |
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| 24 | #include <elf.h> |
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| 25 | |
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| 26 | #ifdef __ILP32__ |
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| 27 | # define RSP_REG "esp" |
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| 28 | #else |
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| 29 | # define RSP_REG "rsp" |
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| 30 | #endif |
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| 31 | |
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| 32 | /* On x86_64 the stack grows down. */ |
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| 33 | #define _STACK_GROWS_DOWN 1 |
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| 34 | |
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| 35 | /* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is |
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| 36 | * present, but it is presumed absent. */ |
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| 37 | #define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X) |
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| 38 | |
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| 39 | /* Access to the stack pointer. The macros are used in alloca_account |
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| 40 | for which they need to act as barriers as well, hence the additional |
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| 41 | (unnecessary) parameters. */ |
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| 42 | #define stackinfo_get_sp() \ |
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| 43 | ({ void *p__; asm volatile ("mov %%" RSP_REG ", %0" : "=r" (p__)); p__; }) |
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| 44 | #define stackinfo_sub_sp(ptr) \ |
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| 45 | ({ ptrdiff_t d__; \ |
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| 46 | asm volatile ("sub %%" RSP_REG " , %0" : "=r" (d__) : "0" (ptr)); \ |
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| 47 | d__; }) |
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| 48 | |
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| 49 | #endif /* stackinfo.h */ |
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| 50 | |
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