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c96772227b
Rather than calling calloc() to allocate space for a page size array to pass to getpagesizes(), just follow the getpagesizes() implementation and allocate MAXPAGESIZES elements on the stack. This avoids the need for the allocation. While this does mean that a new libc is required to take advantage of a new huge page size, that was already true due to getpagesizes() using a static buffer of MAXPAGESIZES elements. Reviewed by: kevans, imp, emaste Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D42710
122 lines
3.6 KiB
C
122 lines
3.6 KiB
C
/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Kyle Evans <kevans@FreeBSD.org>
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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(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/filio.h>
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#include <sys/mman.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include "libc_private.h"
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#define MEMFD_NAME_PREFIX "memfd:"
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/*
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* The path argument is passed to the kernel, but the kernel doesn't currently
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* do anything with it. Linux exposes it in linprocfs for debugging purposes
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* only, but our kernel currently will not do the same.
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*/
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int
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memfd_create(const char *name, unsigned int flags)
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{
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char memfd_name[NAME_MAX + 1];
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size_t pgs[MAXPAGESIZES];
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size_t namelen, pgsize;
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struct shm_largepage_conf slc;
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int error, fd, npgs, oflags, pgidx, saved_errno, shmflags;
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if (name == NULL) {
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errno = EBADF;
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return (-1);
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}
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namelen = strlen(name);
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if (namelen + sizeof(MEMFD_NAME_PREFIX) - 1 > NAME_MAX) {
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errno = EINVAL;
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return (-1);
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}
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if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB |
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MFD_HUGE_MASK)) != 0) {
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errno = EINVAL;
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return (-1);
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}
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/* Size specified but no HUGETLB. */
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if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0) {
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errno = EINVAL;
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return (-1);
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}
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/* We've already validated that we're sufficiently sized. */
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snprintf(memfd_name, NAME_MAX + 1, "%s%s", MEMFD_NAME_PREFIX, name);
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oflags = O_RDWR;
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shmflags = 0;
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if ((flags & MFD_CLOEXEC) != 0)
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oflags |= O_CLOEXEC;
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if ((flags & MFD_ALLOW_SEALING) != 0)
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shmflags |= SHM_ALLOW_SEALING;
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if ((flags & MFD_HUGETLB) != 0)
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shmflags |= SHM_LARGEPAGE;
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else
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shmflags |= SHM_GROW_ON_WRITE;
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fd = __sys_shm_open2(SHM_ANON, oflags, 0, shmflags, memfd_name);
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if (fd == -1 || (flags & MFD_HUGETLB) == 0)
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return (fd);
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npgs = getpagesizes(pgs, nitems(pgs));
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if (npgs == -1)
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goto clean;
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pgsize = (size_t)1 << ((flags & MFD_HUGE_MASK) >> MFD_HUGE_SHIFT);
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for (pgidx = 0; pgidx < npgs; pgidx++) {
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if (pgsize == pgs[pgidx])
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break;
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}
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if (pgidx == npgs) {
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errno = EOPNOTSUPP;
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goto clean;
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}
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memset(&slc, 0, sizeof(slc));
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slc.psind = pgidx;
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slc.alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT;
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error = ioctl(fd, FIOSSHMLPGCNF, &slc);
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if (error == -1)
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goto clean;
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return (fd);
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clean:
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saved_errno = errno;
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close(fd);
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errno = saved_errno;
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return (-1);
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}
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