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
30 char *file_name;
31
32 int in_test;
33 volatile int faulted;
34 volatile void *dar;
35 int errors;
36
segv(int signum,siginfo_t * info,void * ctxt_v)37 static 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
do_read(const volatile void * addr)52 static 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
do_write(const volatile void * addr)60 static 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
check_faulted(void * addr,long page,long subpage,int write)68 static 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
run_test(void * addr,unsigned long size)93 static 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
syscall_available(void)138 static 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
test_anon(void)148 int 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
test_file(void)185 int 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
main(int argc,char * argv[])222 int 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