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The original P2ROUNDUP and P2ROUNDUP_TYPED macros contain -x which triggers PaX's integer overflow detection for unsigned integers. Replace the macros with an equivalent version that does not trigger the overflow. Axioms: A. (-(x)) === (~((x) - 1)) === (~(x) + 1) under two's complement. B. ~(x & y) === ((~(x)) | (~(y))) under De Morgan's law. C. ~(~x) === x under the law of excluded middle. Proof: 0. (-(-(x) & -(align))) original 1. (~(-(x) & -(align)) + 1) by A 2. (((~(-(x))) | (~(-(align)))) + 1) by B 3. (((~(~((x) - 1))) | (~(~((align) - 1)))) + 1) by A 4. (((((x) - 1)) | (((align) - 1))) + 1) by C Q.E.D. Signed-off-by: Jason Zaman <jason@perfinion.com> Reviewed-by: Chris Dunlop <chris@onthe.net.au> Reviewed-by: Richard Yao <ryao@gentoo.org> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3949
97 lines
3.3 KiB
C
97 lines
3.3 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#ifndef _LIBSPL_SYS_SYSMACROS_H
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#define _LIBSPL_SYS_SYSMACROS_H
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#include_next <sys/sysmacros.h>
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/* common macros */
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#ifndef MIN
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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#endif
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#ifndef MAX
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#define MAX(a, b) ((a) < (b) ? (b) : (a))
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#endif
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#ifndef ABS
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#define ABS(a) ((a) < 0 ? -(a) : (a))
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#endif
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#define makedevice(maj, min) makedev(maj, min)
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#define _sysconf(a) sysconf(a)
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#define __NORETURN __attribute__((noreturn))
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/*
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* Compatibility macros/typedefs needed for Solaris -> Linux port
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*/
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#define P2ALIGN(x, align) ((x) & -(align))
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#define P2CROSS(x, y, align) (((x) ^ (y)) > (align) - 1)
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#define P2ROUNDUP(x, align) ((((x) - 1) | ((align) - 1)) + 1)
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#define P2BOUNDARY(off, len, align) \
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(((off) ^ ((off) + (len) - 1)) > (align) - 1)
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#define P2PHASE(x, align) ((x) & ((align) - 1))
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#define P2NPHASE(x, align) (-(x) & ((align) - 1))
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#define P2NPHASE_TYPED(x, align, type) \
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(-(type)(x) & ((type)(align) - 1))
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#define ISP2(x) (((x) & ((x) - 1)) == 0)
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#define IS_P2ALIGNED(v, a) ((((uintptr_t)(v)) & ((uintptr_t)(a) - 1)) == 0)
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/*
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* Typed version of the P2* macros. These macros should be used to ensure
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* that the result is correctly calculated based on the data type of (x),
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* which is passed in as the last argument, regardless of the data
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* type of the alignment. For example, if (x) is of type uint64_t,
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* and we want to round it up to a page boundary using "PAGESIZE" as
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* the alignment, we can do either
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* P2ROUNDUP(x, (uint64_t)PAGESIZE)
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* or
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* P2ROUNDUP_TYPED(x, PAGESIZE, uint64_t)
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*/
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#define P2ALIGN_TYPED(x, align, type) \
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((type)(x) & -(type)(align))
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#define P2PHASE_TYPED(x, align, type) \
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((type)(x) & ((type)(align) - 1))
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#define P2NPHASE_TYPED(x, align, type) \
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(-(type)(x) & ((type)(align) - 1))
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#define P2ROUNDUP_TYPED(x, align, type) \
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((((type)(x) - 1) | ((type)(align) - 1)) + 1)
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#define P2END_TYPED(x, align, type) \
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(-(~(type)(x) & -(type)(align)))
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#define P2PHASEUP_TYPED(x, align, phase, type) \
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((type)(phase) - (((type)(phase) - (type)(x)) & -(type)(align)))
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#define P2CROSS_TYPED(x, y, align, type) \
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(((type)(x) ^ (type)(y)) > (type)(align) - 1)
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#define P2SAMEHIGHBIT_TYPED(x, y, type) \
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(((type)(x) ^ (type)(y)) < ((type)(x) & (type)(y)))
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/* avoid any possibility of clashing with <stddef.h> version */
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#if defined(_KERNEL) && !defined(_KMEMUSER) && !defined(offsetof)
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#define offsetof(s, m) ((size_t)(&(((s *)0)->m)))
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#endif
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#endif /* _LIBSPL_SYS_SYSMACROS_H */
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