Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <string.h>
3#include <fcntl.h>
4#include "../kselftest.h"
5#include "vm_util.h"
6
7#define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
8#define SMAP_FILE_PATH "/proc/self/smaps"
9#define MAX_LINE_LENGTH 500
10
11uint64_t pagemap_get_entry(int fd, char *start)
12{
13 const unsigned long pfn = (unsigned long)start / getpagesize();
14 uint64_t entry;
15 int ret;
16
17 ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
18 if (ret != sizeof(entry))
19 ksft_exit_fail_msg("reading pagemap failed\n");
20 return entry;
21}
22
23bool pagemap_is_softdirty(int fd, char *start)
24{
25 uint64_t entry = pagemap_get_entry(fd, start);
26
27 // Check if dirty bit (55th bit) is set
28 return entry & 0x0080000000000000ull;
29}
30
31bool pagemap_is_swapped(int fd, char *start)
32{
33 uint64_t entry = pagemap_get_entry(fd, start);
34
35 return entry & 0x4000000000000000ull;
36}
37
38bool pagemap_is_populated(int fd, char *start)
39{
40 uint64_t entry = pagemap_get_entry(fd, start);
41
42 /* Present or swapped. */
43 return entry & 0xc000000000000000ull;
44}
45
46unsigned long pagemap_get_pfn(int fd, char *start)
47{
48 uint64_t entry = pagemap_get_entry(fd, start);
49
50 /* If present (63th bit), PFN is at bit 0 -- 54. */
51 if (entry & 0x8000000000000000ull)
52 return entry & 0x007fffffffffffffull;
53 return -1ul;
54}
55
56void clear_softdirty(void)
57{
58 int ret;
59 const char *ctrl = "4";
60 int fd = open("/proc/self/clear_refs", O_WRONLY);
61
62 if (fd < 0)
63 ksft_exit_fail_msg("opening clear_refs failed\n");
64 ret = write(fd, ctrl, strlen(ctrl));
65 close(fd);
66 if (ret != strlen(ctrl))
67 ksft_exit_fail_msg("writing clear_refs failed\n");
68}
69
70bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len)
71{
72 while (fgets(buf, len, fp)) {
73 if (!strncmp(buf, pattern, strlen(pattern)))
74 return true;
75 }
76 return false;
77}
78
79uint64_t read_pmd_pagesize(void)
80{
81 int fd;
82 char buf[20];
83 ssize_t num_read;
84
85 fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
86 if (fd == -1)
87 ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
88
89 num_read = read(fd, buf, 19);
90 if (num_read < 1) {
91 close(fd);
92 ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
93 }
94 buf[num_read] = '\0';
95 close(fd);
96
97 return strtoul(buf, NULL, 10);
98}
99
100bool __check_huge(void *addr, char *pattern, int nr_hpages,
101 uint64_t hpage_size)
102{
103 uint64_t thp = -1;
104 int ret;
105 FILE *fp;
106 char buffer[MAX_LINE_LENGTH];
107 char addr_pattern[MAX_LINE_LENGTH];
108
109 ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
110 (unsigned long) addr);
111 if (ret >= MAX_LINE_LENGTH)
112 ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
113
114 fp = fopen(SMAP_FILE_PATH, "r");
115 if (!fp)
116 ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP_FILE_PATH);
117
118 if (!check_for_pattern(fp, addr_pattern, buffer, sizeof(buffer)))
119 goto err_out;
120
121 /*
122 * Fetch the pattern in the same block and check the number of
123 * hugepages.
124 */
125 if (!check_for_pattern(fp, pattern, buffer, sizeof(buffer)))
126 goto err_out;
127
128 snprintf(addr_pattern, MAX_LINE_LENGTH, "%s%%9ld kB", pattern);
129
130 if (sscanf(buffer, addr_pattern, &thp) != 1)
131 ksft_exit_fail_msg("Reading smap error\n");
132
133err_out:
134 fclose(fp);
135 return thp == (nr_hpages * (hpage_size >> 10));
136}
137
138bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size)
139{
140 return __check_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
141}
142
143bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size)
144{
145 return __check_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
146}
147
148bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size)
149{
150 return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
151}