7c6c1f8b59
Today's risc-v psABI meeting brought up the topic of CFI-related ABI changes, and FreeBSD wasn't worried about jmp_buf because they already had twice the space we do (OpenBSD matches us, presumably because they too just picked "the next power of two" over what they actually required), and glibc wasn't worried because they have a hilariously large sigset_t that they can steal space from (and apparently already did to support the x86-64 CET shadow stack). So rather than continue to assume that our minimal amount of free space will suffice, let's just double it while our ABI isn't yet fixed, and know we won't have to worry about it in a couple of years time when we actually have riscv64 hardware shadow stack. Test: treehugger Change-Id: I2d4cb2f5db2ac8085a2c9e9ad4f910d0d4792005
132 lines
4.8 KiB
C
132 lines
4.8 KiB
C
/* $OpenBSD: setjmp.h,v 1.5 2005/12/13 00:35:22 millert Exp $ */
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/* $NetBSD: setjmp.h,v 1.11 1994/12/20 10:35:44 cgd Exp $ */
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)setjmp.h 8.2 (Berkeley) 1/21/94
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*/
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#pragma once
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/**
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* @file setjmp.h
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* @brief Non-local jumps.
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*/
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#include <sys/cdefs.h>
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#if defined(__aarch64__)
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/**
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* The size in words of an arm64 jmp_buf. Room for callee-saved registers,
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* including floating point, stack pointer and program counter, various
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* internal implementation details, and leaving some free space.
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*
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* Coincidentally matches OpenBSD, though they also save/restore the
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* floating point status register too.
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*/
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#define _JBLEN 32
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#elif defined(__arm__)
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/** The size in words of an arm32 jmp_buf. Inherited from OpenBSD. */
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#define _JBLEN 64
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#elif defined(__i386__)
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/** The size in words of an x86 jmp_buf. Inherited from OpenBSD. */
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#define _JBLEN 10
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#elif defined(__riscv)
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/**
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* The size in words of a riscv64 jmp_buf. Room for callee-saved registers,
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* including floating point, stack pointer and program counter, various
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* internal implementation details, and leaving lots of free space.
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*
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* Deliberately very large given the uncertainty around the final form of
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* hardware shadow stack, and the fact that x86-64 glibc needed to steal
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* space from their enormous sigset_t (which we don't have) to be able to
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* implement the CET shadow stack.
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*/
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#define _JBLEN 64
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#elif defined(__x86_64__)
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/** The size in words of an x86-64 jmp_buf. Inherited from OpenBSD. */
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#define _JBLEN 11
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#endif
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/** The type of the buffer used by sigsetjmp()/siglongjmp(). */
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typedef long sigjmp_buf[_JBLEN + 1];
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/** The type of the buffer used by setjmp()/longjmp(). */
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typedef long jmp_buf[_JBLEN];
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#undef _JBLEN
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__BEGIN_DECLS
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/**
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* Equivalent to sigsetjmp() with the second argument 0, so that the signal
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* mask is not saved.
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*/
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int _setjmp(jmp_buf __env) __returns_twice;
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/** Equivalent to siglongjmp(). */
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__noreturn void _longjmp(jmp_buf __env, int __value);
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/**
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* Equivalent to sigsetjmp() with the second argument 1, so that the signal
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* mask is saved.
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*/
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int setjmp(jmp_buf __env) __returns_twice;
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/** C11 says setjmp() must be a macro, but Android already had a function. */
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#define setjmp(__env) setjmp(__env)
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/** Equivalent to siglongjmp(). */
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__noreturn void longjmp(jmp_buf __env, int __value);
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/**
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* [sigsetjmp(3)](http://man7.org/linux/man-pages/man3/sigsetjmp.3.html)
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* sets the target of a future siglongjmp() call, saving or not saving the
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* current signal mask based on the second argument.
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*
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* Returns 0 when first called, and returns the value passed to siglongjmp()
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* when returning here as a result of a siglongjmp() call.
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*/
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int sigsetjmp(sigjmp_buf __env, int __save_signal_mask) __returns_twice;
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/**
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* [siglongjmp(3)](http://man7.org/linux/man-pages/man3/siglongjmp.3.html)
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* transfers control back to the site of the sigsetjmp() call that initialized
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* the given jump buffer, returning the given value.
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*
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* Does not return.
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*/
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__noreturn void siglongjmp(sigjmp_buf __env, int __value);
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__END_DECLS
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