1/* SPDX-License-Identifier: GPL-2.0 */
 2
 3#ifndef __KSELFTEST_VM_UTIL_H
 4#define __KSELFTEST_VM_UTIL_H
 5
 6#include <stdint.h>
 7#include <sys/mman.h>
 8#include <err.h>
 9#include <string.h> /* ffsl() */
10#include <unistd.h> /* _SC_PAGESIZE */
11
12static unsigned int __page_size;
13static unsigned int __page_shift;
14
15static inline unsigned int page_size(void)
16{
17	if (!__page_size)
18		__page_size = sysconf(_SC_PAGESIZE);
19	return __page_size;
20}
21
22static inline unsigned int page_shift(void)
23{
24	if (!__page_shift)
25		__page_shift = (ffsl(page_size()) - 1);
26	return __page_shift;
27}
28
29#define PAGE_SHIFT	(page_shift())
30#define PAGE_SIZE	(page_size())
31/*
32 * On ppc64 this will only work with radix 2M hugepage size
33 */
34#define HPAGE_SHIFT 21
35#define HPAGE_SIZE (1 << HPAGE_SHIFT)
36
37#define PAGEMAP_PRESENT(ent)	(((ent) & (1ull << 63)) != 0)
38#define PAGEMAP_PFN(ent)	((ent) & ((1ull << 55) - 1))
39
40
41static inline int64_t allocate_transhuge(void *ptr, int pagemap_fd)
42{
43	uint64_t ent[2];
44
45	/* drop pmd */
46	if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
47		 MAP_FIXED | MAP_ANONYMOUS |
48		 MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
49		errx(2, "mmap transhuge");
50
51	if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
52		err(2, "MADV_HUGEPAGE");
53
54	/* allocate transparent huge page */
55	*(volatile void **)ptr = ptr;
56
57	if (pread(pagemap_fd, ent, sizeof(ent),
58		  (uintptr_t)ptr >> (PAGE_SHIFT - 3)) != sizeof(ent))
59		err(2, "read pagemap");
60
61	if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
62	    PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
63	    !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - PAGE_SHIFT)) - 1)))
64		return PAGEMAP_PFN(ent[0]);
65
66	return -1;
67}
68
69#endif