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/* $OpenBSD: mmap_hint.c,v 1.5 2017/07/13 11:24:58 bluhm Exp $ */
/*
* Copyright (c) 2011 Ariane van der Steldt <ariane@stack.nl>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/tree.h>
#include <machine/pmap.h>
#include <machine/vmparam.h>
#include <err.h>
#include <sysexits.h>
#include <stdio.h>
#define MAX_HINT_DIST (2UL * 1024 * 1024 * 1024)
int errors = 0;
void *
mmap_hint(void *hint)
{
void *p;
size_t delta;
p = mmap(hint, 1, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
if (p == MAP_FAILED) {
warn("mmap(addr=%p, len=1) failed", hint);
errors++;
return MAP_FAILED;
} else if (p == NULL) {
warnx("mmap(addr=%p, len=1) mapped at address 0", hint);
errors++;
return MAP_FAILED;
} else
fprintf(stderr, " -> %p\n", p);
if (hint > p)
delta = hint - p;
else
delta = p - hint;
if (hint != NULL && delta > MAX_HINT_DIST) {
warnx("hinted allocation more than %#zx bytes away from hint: "
"hint %p, result %p", delta, hint, p);
errors++;
return MAP_FAILED;
}
return p;
}
int
main()
{
void *p, *hint;
/* Check that unhinted allocation works properly. */
hint = NULL;
fprintf(stderr, "1: Checking hint %p mmap\n", hint);
p = mmap_hint(hint);
/* Check hinted allocation at top of map. */
hint = (void *)((VM_MAXUSER_ADDRESS & ~PAGE_MASK) - PAGE_SIZE);
fprintf(stderr, "2: Checking hint page below "
"VM_MAXUSER_ADDRESS %p mmap\n", hint);
p = mmap_hint(hint);
/* Check hinted allocation at bottom of map. */
hint = (void *)VM_MIN_ADDRESS;
fprintf(stderr, "3: Checking hint VM_MIN_ADDRESS %p mmap\n", hint);
p = mmap_hint(hint);
/*
* Check that hinted allocation doesn't overwrite existing allocation.
*/
if (p == MAP_FAILED) {
fprintf(stderr, "4: Skipping test: required previous test "
"to succeed");
goto skip4;
}
hint = p;
fprintf(stderr, "4: Checking hint %p mmap, which is in use\n", hint);
p = mmap_hint(hint);
if (p == hint) {
warnx("hinted allocation %p overwrites previous allocation %p",
hint, p);
errors++;
}
skip4:
return errors;
}
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