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0766f278d8
Most kernel memory that is allocated after boot does not need to be executable. There are a few exceptions. For example, kernel modules do need executable memory, but they don't use UMA or malloc(9). The BPF JIT compiler also needs executable memory and did use malloc(9) until r317072. (Note that a side effect of r316767 was that the "small allocation" path in UMA on amd64 already returned non-executable memory. This meant that some calls to malloc(9) or the UMA zone(9) allocator could return executable memory, while others could return non-executable memory. This change makes the behavior consistent.) This change makes malloc(9) return non-executable memory unless the new M_EXEC flag is specified. After this change, the UMA zone(9) allocator will always return non-executable memory, and a KASSERT will catch attempts to use the M_EXEC flag to allocate executable memory using uma_zalloc() or its variants. Allocations that do need executable memory have various choices. They may use the M_EXEC flag to malloc(9), or they may use a different VM interfact to obtain executable pages. Now that malloc(9) again allows executable allocations, this change also reverts most of r317072. PR: 228927 Reviewed by: alc, kib, markj, jhb (previous version) Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D15691
93 lines
3.3 KiB
C
93 lines
3.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (C) 2002-2003 NetGroup, Politecnico di Torino (Italy)
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* Copyright (C) 2005-2009 Jung-uk Kim <jkim@FreeBSD.org>
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* All rights reserved.
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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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*
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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 Politecnico di Torino nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _NET_BPF_JITTER_H_
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#define _NET_BPF_JITTER_H_
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#ifdef _KERNEL
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MALLOC_DECLARE(M_BPFJIT);
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#endif
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extern int bpf_jitter_enable;
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/*
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* Prototype of a filtering function created by the jitter.
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*
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* The syntax and the meaning of the parameters is analogous to the one of
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* bpf_filter(). Notice that the filter is not among the parameters because
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* it is hardwired in the function.
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*/
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typedef u_int (*bpf_filter_func)(u_char *, u_int, u_int);
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/* Structure describing a native filtering program created by the jitter. */
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typedef struct bpf_jit_filter {
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/* The native filtering binary, in the form of a bpf_filter_func. */
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bpf_filter_func func;
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size_t size;
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} bpf_jit_filter;
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/*
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* BPF jitter, builds a machine function from a BPF program.
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*
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* param fp The BPF pseudo-assembly filter that will be translated
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* into native code.
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* param nins Number of instructions of the input filter.
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* return The bpf_jit_filter structure containing the native filtering
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* binary.
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*
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* bpf_jitter allocates the buffers for the new native filter and
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* then translates the program pointed by fp calling bpf_jit_compile().
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*/
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bpf_jit_filter *bpf_jitter(struct bpf_insn *fp, int nins);
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/*
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* Deletes a filtering function that was previously created by bpf_jitter().
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*
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* param filter The filter to destroy.
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*
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* This function frees the variuos buffers (code, memory, etc.) associated
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* with a filtering function.
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*/
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void bpf_destroy_jit_filter(bpf_jit_filter *filter);
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/*
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* Declarations for machine-dependent functions.
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*/
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struct bpf_insn;
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bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, size_t *);
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#endif /* _NET_BPF_JITTER_H_ */
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