1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Exercise /dev/mem mmap cases that have been troublesome in the past
4 *
5 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
6 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
7 */
8
9#include <stdlib.h>
10#include <stdio.h>
11#include <sys/types.h>
12#include <dirent.h>
13#include <fcntl.h>
14#include <fnmatch.h>
15#include <string.h>
16#include <sys/ioctl.h>
17#include <sys/mman.h>
18#include <sys/stat.h>
19#include <unistd.h>
20#include <linux/pci.h>
21
22int sum;
23
24static int map_mem(char *path, off_t offset, size_t length, int touch)
25{
26	int fd, rc;
27	void *addr;
28	int *c;
29
30	fd = open(path, O_RDWR);
31	if (fd == -1) {
32		perror(path);
33		return -1;
34	}
35
36	if (fnmatch("/proc/bus/pci/*", path, 0) == 0) {
37		rc = ioctl(fd, PCIIOC_MMAP_IS_MEM);
38		if (rc == -1)
39			perror("PCIIOC_MMAP_IS_MEM ioctl");
40	}
41
42	addr = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
43	if (addr == MAP_FAILED)
44		return 1;
45
46	if (touch) {
47		c = (int *) addr;
48		while (c < (int *) (addr + length))
49			sum += *c++;
50	}
51
52	rc = munmap(addr, length);
53	if (rc == -1) {
54		perror("munmap");
55		return -1;
56	}
57
58	close(fd);
59	return 0;
60}
61
62static int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
63{
64	struct dirent **namelist;
65	char *name, *path2;
66	int i, n, r, rc = 0, result = 0;
67	struct stat buf;
68
69	n = scandir(path, &namelist, 0, alphasort);
70	if (n < 0) {
71		perror("scandir");
72		return -1;
73	}
74
75	for (i = 0; i < n; i++) {
76		name = namelist[i]->d_name;
77
78		if (fnmatch(".", name, 0) == 0)
79			goto skip;
80		if (fnmatch("..", name, 0) == 0)
81			goto skip;
82
83		path2 = malloc(strlen(path) + strlen(name) + 3);
84		strcpy(path2, path);
85		strcat(path2, "/");
86		strcat(path2, name);
87
88		if (fnmatch(file, name, 0) == 0) {
89			rc = map_mem(path2, offset, length, touch);
90			if (rc == 0)
91				fprintf(stderr, "PASS: %s 0x%lx-0x%lx is %s\n", path2, offset, offset + length, touch ? "readable" : "mappable");
92			else if (rc > 0)
93				fprintf(stderr, "PASS: %s 0x%lx-0x%lx not mappable\n", path2, offset, offset + length);
94			else {
95				fprintf(stderr, "FAIL: %s 0x%lx-0x%lx not accessible\n", path2, offset, offset + length);
96				return rc;
97			}
98		} else {
99			r = lstat(path2, &buf);
100			if (r == 0 && S_ISDIR(buf.st_mode)) {
101				rc = scan_tree(path2, file, offset, length, touch);
102				if (rc < 0)
103					return rc;
104			}
105		}
106
107		result |= rc;
108		free(path2);
109
110skip:
111		free(namelist[i]);
112	}
113	free(namelist);
114	return result;
115}
116
117char buf[1024];
118
119static int read_rom(char *path)
120{
121	int fd, rc;
122	size_t size = 0;
123
124	fd = open(path, O_RDWR);
125	if (fd == -1) {
126		perror(path);
127		return -1;
128	}
129
130	rc = write(fd, "1", 2);
131	if (rc <= 0) {
132		close(fd);
133		perror("write");
134		return -1;
135	}
136
137	do {
138		rc = read(fd, buf, sizeof(buf));
139		if (rc > 0)
140			size += rc;
141	} while (rc > 0);
142
143	close(fd);
144	return size;
145}
146
147static int scan_rom(char *path, char *file)
148{
149	struct dirent **namelist;
150	char *name, *path2;
151	int i, n, r, rc = 0, result = 0;
152	struct stat buf;
153
154	n = scandir(path, &namelist, 0, alphasort);
155	if (n < 0) {
156		perror("scandir");
157		return -1;
158	}
159
160	for (i = 0; i < n; i++) {
161		name = namelist[i]->d_name;
162
163		if (fnmatch(".", name, 0) == 0)
164			goto skip;
165		if (fnmatch("..", name, 0) == 0)
166			goto skip;
167
168		path2 = malloc(strlen(path) + strlen(name) + 3);
169		strcpy(path2, path);
170		strcat(path2, "/");
171		strcat(path2, name);
172
173		if (fnmatch(file, name, 0) == 0) {
174			rc = read_rom(path2);
175
176			/*
177			 * It's OK if the ROM is unreadable.  Maybe there
178			 * is no ROM, or some other error occurred.  The
179			 * important thing is that no MCA happened.
180			 */
181			if (rc > 0)
182				fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
183			else {
184				fprintf(stderr, "PASS: %s not readable\n", path2);
185				return rc;
186			}
187		} else {
188			r = lstat(path2, &buf);
189			if (r == 0 && S_ISDIR(buf.st_mode)) {
190				rc = scan_rom(path2, file);
191				if (rc < 0)
192					return rc;
193			}
194		}
195
196		result |= rc;
197		free(path2);
198
199skip:
200		free(namelist[i]);
201	}
202	free(namelist);
203	return result;
204}
205
206int main(void)
207{
208	int rc;
209
210	if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
211		fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
212	else
213		fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");
214
215	/*
216	 * It's not safe to blindly read the VGA frame buffer.  If you know
217	 * how to poke the card the right way, it should respond, but it's
218	 * not safe in general.  Many machines, e.g., Intel chipsets, cover
219	 * up a non-responding card by just returning -1, but others will
220	 * report the failure as a machine check.
221	 */
222	if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
223		fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
224	else
225		fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");
226
227	if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
228		fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
229	else
230		fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");
231
232	/*
233	 * Often you can map all the individual pieces above (0-0xA0000,
234	 * 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
235	 * thing at once.  This is because the individual pieces use different
236	 * attributes, and there's no single attribute supported over the
237	 * whole region.
238	 */
239	rc = map_mem("/dev/mem", 0, 1024*1024, 0);
240	if (rc == 0)
241		fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
242	else if (rc > 0)
243		fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
244	else
245		fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");
246
247	scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
248	scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
249	scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
250	scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);
251
252	scan_rom("/sys/devices", "rom");
253
254	scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
255	scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
256	scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
257	scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);
258
259	return rc;
260}
261