1/*
2 * Copyright IBM Corp.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2.1 of the GNU Lesser General Public License
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it would be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11 *
12 */
13
14#include <assert.h>
15#include <errno.h>
16#include <fcntl.h>
17#include <signal.h>
18#include <stdarg.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <sys/mman.h>
23#include <sys/ptrace.h>
24#include <sys/syscall.h>
25#include <ucontext.h>
26#include <unistd.h>
27
28#include "utils.h"
29
30char *file_name;
31
32int in_test;
33volatile int faulted;
34volatile void *dar;
35int errors;
36
37static void segv(int signum, siginfo_t *info, void *ctxt_v)
38{
39	ucontext_t *ctxt = (ucontext_t *)ctxt_v;
40	struct pt_regs *regs = ctxt->uc_mcontext.regs;
41
42	if (!in_test) {
43		fprintf(stderr, "Segfault outside of test !\n");
44		exit(1);
45	}
46
47	faulted = 1;
48	dar = (void *)regs->dar;
49	regs->nip += 4;
50}
51
52static inline void do_read(const volatile void *addr)
53{
54	int ret;
55
56	asm volatile("lwz %0,0(%1); twi 0,%0,0; isync;\n"
57		     : "=r" (ret) : "r" (addr) : "memory");
58}
59
60static inline void do_write(const volatile void *addr)
61{
62	int val = 0x1234567;
63
64	asm volatile("stw %0,0(%1); sync; \n"
65		     : : "r" (val), "r" (addr) : "memory");
66}
67
68static inline void check_faulted(void *addr, long page, long subpage, int write)
69{
70	int want_fault = (subpage == ((page + 3) % 16));
71
72	if (write)
73		want_fault |= (subpage == ((page + 1) % 16));
74
75	if (faulted != want_fault) {
76		printf("Failed at %p (p=%ld,sp=%ld,w=%d), want=%s, got=%s !\n",
77		       addr, page, subpage, write,
78		       want_fault ? "fault" : "pass",
79		       faulted ? "fault" : "pass");
80		++errors;
81	}
82
83	if (faulted) {
84		if (dar != addr) {
85			printf("Fault expected at %p and happened at %p !\n",
86			       addr, dar);
87		}
88		faulted = 0;
89		asm volatile("sync" : : : "memory");
90	}
91}
92
93static int run_test(void *addr, unsigned long size)
94{
95	unsigned int *map;
96	long i, j, pages, err;
97
98	pages = size / 0x10000;
99	map = malloc(pages * 4);
100	assert(map);
101
102	/*
103	 * for each page, mark subpage i % 16 read only and subpage
104	 * (i + 3) % 16 inaccessible
105	 */
106	for (i = 0; i < pages; i++) {
107		map[i] = (0x40000000 >> (((i + 1) * 2) % 32)) |
108			(0xc0000000 >> (((i + 3) * 2) % 32));
109	}
110
111	err = syscall(__NR_subpage_prot, addr, size, map);
112	if (err) {
113		perror("subpage_perm");
114		return 1;
115	}
116	free(map);
117
118	in_test = 1;
119	errors = 0;
120	for (i = 0; i < pages; i++) {
121		for (j = 0; j < 16; j++, addr += 0x1000) {
122			do_read(addr);
123			check_faulted(addr, i, j, 0);
124			do_write(addr);
125			check_faulted(addr, i, j, 1);
126		}
127	}
128
129	in_test = 0;
130	if (errors) {
131		printf("%d errors detected\n", errors);
132		return 1;
133	}
134
135	return 0;
136}
137
138static int syscall_available(void)
139{
140	int rc;
141
142	errno = 0;
143	rc = syscall(__NR_subpage_prot, 0, 0, 0);
144
145	return rc == 0 || (errno != ENOENT && errno != ENOSYS);
146}
147
148int test_anon(void)
149{
150	unsigned long align;
151	struct sigaction act = {
152		.sa_sigaction = segv,
153		.sa_flags = SA_SIGINFO
154	};
155	void *mallocblock;
156	unsigned long mallocsize;
157
158	SKIP_IF(!syscall_available());
159
160	if (getpagesize() != 0x10000) {
161		fprintf(stderr, "Kernel page size must be 64K!\n");
162		return 1;
163	}
164
165	sigaction(SIGSEGV, &act, NULL);
166
167	mallocsize = 4 * 16 * 1024 * 1024;
168
169	FAIL_IF(posix_memalign(&mallocblock, 64 * 1024, mallocsize));
170
171	align = (unsigned long)mallocblock;
172	if (align & 0xffff)
173		align = (align | 0xffff) + 1;
174
175	mallocblock = (void *)align;
176
177	printf("allocated malloc block of 0x%lx bytes at %p\n",
178	       mallocsize, mallocblock);
179
180	printf("testing malloc block...\n");
181
182	return run_test(mallocblock, mallocsize);
183}
184
185int test_file(void)
186{
187	struct sigaction act = {
188		.sa_sigaction = segv,
189		.sa_flags = SA_SIGINFO
190	};
191	void *fileblock;
192	off_t filesize;
193	int fd;
194
195	SKIP_IF(!syscall_available());
196
197	fd = open(file_name, O_RDWR);
198	if (fd == -1) {
199		perror("failed to open file");
200		return 1;
201	}
202	sigaction(SIGSEGV, &act, NULL);
203
204	filesize = lseek(fd, 0, SEEK_END);
205	if (filesize & 0xffff)
206		filesize &= ~0xfffful;
207
208	fileblock = mmap(NULL, filesize, PROT_READ | PROT_WRITE,
209			 MAP_SHARED, fd, 0);
210	if (fileblock == MAP_FAILED) {
211		perror("failed to map file");
212		return 1;
213	}
214	printf("allocated %s for 0x%lx bytes at %p\n",
215	       file_name, filesize, fileblock);
216
217	printf("testing file map...\n");
218
219	return run_test(fileblock, filesize);
220}
221
222int main(int argc, char *argv[])
223{
224	int rc;
225
226	rc = test_harness(test_anon, "subpage_prot_anon");
227	if (rc)
228		return rc;
229
230	if (argc > 1)
231		file_name = argv[1];
232	else
233		file_name = "tempfile";
234
235	return test_harness(test_file, "subpage_prot_file");
236}
237