79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
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// SPDX-License-Identifier: LGPL-2.1-or-later
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/*
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* Copyright (C) 2013 Joonsoo Kim, LG Electronics.
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* Author: Joonsoo Kim
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*/
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/*\
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* [Description]
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*
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* Test sanity of cow optimization on page cache. If a page in page cache
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* has only 1 ref count, it is mapped for a private mapping directly and
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* is overwritten freely, so next time we access the page, we can see
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* corrupt data.
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <sys/mount.h>
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#include <limits.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include "hugetlb.h"
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#define MNTPOINT "hugetlbfs/"
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static long hpage_size;
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static int huge_fd = -1;
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static void run_test(void)
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{
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char *p;
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char c;
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p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
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huge_fd, 0);
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*p = 's';
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tst_res(TINFO, "Write %c to %p via shared mapping", *p, p);
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SAFE_MUNMAP(p, hpage_size);
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p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
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huge_fd, 0);
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*p = 'p';
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tst_res(TINFO, "Write %c to %p via private mapping", *p, p);
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SAFE_MUNMAP(p, hpage_size);
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p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
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huge_fd, 0);
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c = *p;
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tst_res(TINFO, "Read %c from %p via shared mapping", *p, p);
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SAFE_MUNMAP(p, hpage_size);
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/* Direct write from huge page */
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if (c != 's')
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tst_res(TFAIL, "Data got corrupted.");
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else
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tst_res(TPASS, "Successful");
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}
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static void setup(void)
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{
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hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
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huge_fd = tst_creat_unlinked(MNTPOINT, 0);
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}
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static void cleanup(void)
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{
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SAFE_CLOSE(huge_fd);
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}
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static struct tst_test test = {
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.needs_root = 1,
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.mntpoint = MNTPOINT,
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.needs_hugetlbfs = 1,
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.setup = setup,
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.cleanup = cleanup,
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.test_all = run_test,
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.hugepages = {2, TST_NEEDS},
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};
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