Merge branch 'next' into for-linus
[deliverable/linux.git] / arch / um / os-Linux / start_up.c
CommitLineData
60d339f6 1/*
ba180fd4 2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
1da177e4
LT
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
0f80bc85 7#include <stdlib.h>
ba180fd4 8#include <stdarg.h>
1da177e4 9#include <unistd.h>
1da177e4 10#include <errno.h>
ba180fd4
JD
11#include <fcntl.h>
12#include <sched.h>
13#include <signal.h>
14#include <string.h>
1da177e4 15#include <sys/mman.h>
ba180fd4
JD
16#include <sys/stat.h>
17#include <sys/wait.h>
fdfa4c95
ST
18#include <sys/time.h>
19#include <sys/resource.h>
1da177e4 20#include <asm/unistd.h>
37185b33
AV
21#include <init.h>
22#include <os.h>
23#include <mem_user.h>
24#include <ptrace_user.h>
25#include <registers.h>
26#include <skas.h>
1da177e4 27
626c59f5 28static void ptrace_child(void)
1da177e4
LT
29{
30 int ret;
512b6fb1 31 /* Calling os_getpid because some libcs cached getpid incorrectly */
1da177e4
LT
32 int pid = os_getpid(), ppid = getppid();
33 int sc_result;
34
626c59f5
WC
35 if (change_sig(SIGWINCH, 0) < 0 ||
36 ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
1da177e4 37 perror("ptrace");
512b6fb1 38 kill(pid, SIGKILL);
1da177e4 39 }
73c8f444 40 kill(pid, SIGSTOP);
1da177e4 41
ba180fd4
JD
42 /*
43 * This syscall will be intercepted by the parent. Don't call more than
44 * once, please.
45 */
1da177e4
LT
46 sc_result = os_getpid();
47
48 if (sc_result == pid)
ba180fd4
JD
49 /* Nothing modified by the parent, we are running normally. */
50 ret = 1;
1da177e4 51 else if (sc_result == ppid)
ba180fd4
JD
52 /*
53 * Expected in check_ptrace and check_sysemu when they succeed
54 * in modifying the stack frame
55 */
56 ret = 0;
1da177e4 57 else
ba180fd4
JD
58 /* Serious trouble! This could be caused by a bug in host 2.6
59 * SKAS3/2.6 patch before release -V6, together with a bug in
60 * the UML code itself.
61 */
62 ret = 2;
bf8fde78
JD
63
64 exit(ret);
1da177e4
LT
65}
66
c9a3072d 67static void fatal_perror(const char *str)
3a150e1d
JD
68{
69 perror(str);
70 exit(1);
71}
72
73static void fatal(char *fmt, ...)
74{
75 va_list list;
76
77 va_start(list, fmt);
626c59f5 78 vfprintf(stderr, fmt, list);
3a150e1d 79 va_end(list);
3a150e1d
JD
80
81 exit(1);
82}
83
84static void non_fatal(char *fmt, ...)
85{
86 va_list list;
87
88 va_start(list, fmt);
626c59f5 89 vfprintf(stderr, fmt, list);
3a150e1d 90 va_end(list);
3a150e1d
JD
91}
92
3cdaf455 93static int start_ptraced_child(void)
1da177e4 94{
1da177e4 95 int pid, n, status;
60d339f6 96
3cdaf455
JD
97 pid = fork();
98 if (pid == 0)
99 ptrace_child();
100 else if (pid < 0)
101 fatal_perror("start_ptraced_child : fork failed");
ba180fd4 102
1da177e4 103 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
ba180fd4 104 if (n < 0)
3cdaf455 105 fatal_perror("check_ptrace : waitpid failed");
ba180fd4 106 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
3a150e1d 107 fatal("check_ptrace : expected SIGSTOP, got status = %d",
1da177e4
LT
108 status);
109
9eae9b13 110 return pid;
1da177e4
LT
111}
112
60d339f6
GS
113/* When testing for SYSEMU support, if it is one of the broken versions, we
114 * must just avoid using sysemu, not panic, but only if SYSEMU features are
115 * broken.
1da177e4 116 * So only for SYSEMU features we test mustpanic, while normal host features
60d339f6
GS
117 * must work anyway!
118 */
3cdaf455 119static int stop_ptraced_child(int pid, int exitcode, int mustexit)
1da177e4
LT
120{
121 int status, n, ret = 0;
122
f1ef9167
JD
123 if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
124 perror("stop_ptraced_child : ptrace failed");
125 return -1;
126 }
1da177e4 127 CATCH_EINTR(n = waitpid(pid, &status, 0));
ba180fd4 128 if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
1da177e4
LT
129 int exit_with = WEXITSTATUS(status);
130 if (exit_with == 2)
3a150e1d 131 non_fatal("check_ptrace : child exited with status 2. "
cf6acedb 132 "\nDisabling SYSEMU support.\n");
3a150e1d
JD
133 non_fatal("check_ptrace : child exited with exitcode %d, while "
134 "expecting %d; status 0x%x\n", exit_with,
135 exitcode, status);
136 if (mustexit)
137 exit(1);
1da177e4
LT
138 ret = -1;
139 }
140
1da177e4
LT
141 return ret;
142}
143
7242a400 144/* Changed only during early boot */
60d339f6
GS
145static int force_sysemu_disabled = 0;
146
1da177e4
LT
147static int __init nosysemu_cmd_param(char *str, int* add)
148{
149 force_sysemu_disabled = 1;
150 return 0;
151}
152
153__uml_setup("nosysemu", nosysemu_cmd_param,
60d339f6
GS
154"nosysemu\n"
155" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
156" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
157" behaviour of ptrace() and helps reducing host context switch rate.\n"
158" To make it working, you need a kernel patch for your host, too.\n"
159" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
160" information.\n\n");
1da177e4
LT
161
162static void __init check_sysemu(void)
163{
cf6acedb 164 unsigned long regs[MAX_REG_NR];
9eae9b13 165 int pid, n, status, count=0;
1da177e4 166
3a150e1d 167 non_fatal("Checking syscall emulation patch for ptrace...");
1da177e4 168 sysemu_supported = 0;
3cdaf455 169 pid = start_ptraced_child();
1da177e4 170
ba180fd4 171 if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
1da177e4
LT
172 goto fail;
173
174 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
175 if (n < 0)
3a150e1d 176 fatal_perror("check_sysemu : wait failed");
ba180fd4 177 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
f1ef9167 178 fatal("check_sysemu : expected SIGTRAP, got status = %d\n",
3a150e1d 179 status);
1da177e4 180
ba180fd4 181 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
cf6acedb 182 fatal_perror("check_sysemu : PTRACE_GETREGS failed");
ba180fd4 183 if (PT_SYSCALL_NR(regs) != __NR_getpid) {
cf6acedb
JD
184 non_fatal("check_sysemu got system call number %d, "
185 "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
186 goto fail;
187 }
188
966e803a 189 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
ba180fd4 190 if (n < 0) {
cf6acedb
JD
191 non_fatal("check_sysemu : failed to modify system call "
192 "return");
193 goto fail;
194 }
1da177e4 195
3cdaf455 196 if (stop_ptraced_child(pid, 0, 0) < 0)
1da177e4
LT
197 goto fail_stopped;
198
199 sysemu_supported = 1;
3a150e1d 200 non_fatal("OK\n");
1da177e4
LT
201 set_using_sysemu(!force_sysemu_disabled);
202
3a150e1d 203 non_fatal("Checking advanced syscall emulation patch for ptrace...");
3cdaf455 204 pid = start_ptraced_child();
f9dfefe4 205
ba180fd4 206 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
3a150e1d 207 (void *) PTRACE_O_TRACESYSGOOD) < 0))
5062910a 208 fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed");
f9dfefe4 209
ba180fd4 210 while (1) {
1da177e4 211 count++;
ba180fd4 212 if (ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
1da177e4
LT
213 goto fail;
214 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
ba180fd4 215 if (n < 0)
5062910a 216 fatal_perror("check_sysemu: wait failed");
3a150e1d 217
ba180fd4
JD
218 if (WIFSTOPPED(status) &&
219 (WSTOPSIG(status) == (SIGTRAP|0x80))) {
f1ef9167 220 if (!count) {
5062910a 221 non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
f1ef9167
JD
222 "doesn't singlestep");
223 goto fail;
224 }
966e803a 225 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET,
1da177e4 226 os_getpid());
ba180fd4 227 if (n < 0)
3a150e1d
JD
228 fatal_perror("check_sysemu : failed to modify "
229 "system call return");
1da177e4
LT
230 break;
231 }
ba180fd4 232 else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
f9dfefe4 233 count++;
f1ef9167 234 else {
5062910a 235 non_fatal("check_sysemu: expected SIGTRAP or "
f1ef9167
JD
236 "(SIGTRAP | 0x80), got status = %d\n",
237 status);
238 goto fail;
239 }
1da177e4 240 }
3cdaf455 241 if (stop_ptraced_child(pid, 0, 0) < 0)
1da177e4
LT
242 goto fail_stopped;
243
244 sysemu_supported = 2;
3a150e1d 245 non_fatal("OK\n");
1da177e4 246
ba180fd4 247 if (!force_sysemu_disabled)
1da177e4
LT
248 set_using_sysemu(sysemu_supported);
249 return;
250
251fail:
3cdaf455 252 stop_ptraced_child(pid, 1, 0);
1da177e4 253fail_stopped:
3a150e1d 254 non_fatal("missing\n");
1da177e4
LT
255}
256
60d339f6 257static void __init check_ptrace(void)
1da177e4 258{
1da177e4
LT
259 int pid, syscall, n, status;
260
3a150e1d 261 non_fatal("Checking that ptrace can change system call numbers...");
3cdaf455 262 pid = start_ptraced_child();
1da177e4 263
ba180fd4 264 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
3a150e1d
JD
265 (void *) PTRACE_O_TRACESYSGOOD) < 0))
266 fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
1da177e4 267
ba180fd4
JD
268 while (1) {
269 if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
3a150e1d
JD
270 fatal_perror("check_ptrace : ptrace failed");
271
1da177e4 272 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
ba180fd4 273 if (n < 0)
3a150e1d
JD
274 fatal_perror("check_ptrace : wait failed");
275
ba180fd4 276 if (!WIFSTOPPED(status) ||
3a150e1d
JD
277 (WSTOPSIG(status) != (SIGTRAP | 0x80)))
278 fatal("check_ptrace : expected (SIGTRAP|0x80), "
279 "got status = %d", status);
60d339f6 280
966e803a 281 syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
1da177e4 282 0);
ba180fd4 283 if (syscall == __NR_getpid) {
966e803a 284 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
1da177e4 285 __NR_getppid);
ba180fd4 286 if (n < 0)
3a150e1d
JD
287 fatal_perror("check_ptrace : failed to modify "
288 "system call");
1da177e4
LT
289 break;
290 }
291 }
3cdaf455 292 stop_ptraced_child(pid, 0, 1);
3a150e1d 293 non_fatal("OK\n");
1da177e4
LT
294 check_sysemu();
295}
296
966a082f 297extern void check_tmpexec(void);
0f80bc85 298
36e45463 299static void __init check_coredump_limit(void)
1d94cda0
JD
300{
301 struct rlimit lim;
302 int err = getrlimit(RLIMIT_CORE, &lim);
303
ba180fd4 304 if (err) {
1d94cda0
JD
305 perror("Getting core dump limit");
306 return;
307 }
308
309 printf("Core dump limits :\n\tsoft - ");
ba180fd4 310 if (lim.rlim_cur == RLIM_INFINITY)
1d94cda0
JD
311 printf("NONE\n");
312 else printf("%lu\n", lim.rlim_cur);
313
314 printf("\thard - ");
ba180fd4 315 if (lim.rlim_max == RLIM_INFINITY)
1d94cda0
JD
316 printf("NONE\n");
317 else printf("%lu\n", lim.rlim_max);
318}
319
36e45463 320void __init os_early_checks(void)
1da177e4 321{
576c013d
JD
322 int pid;
323
1d94cda0
JD
324 /* Print out the core dump limits early */
325 check_coredump_limit();
326
60d339f6 327 check_ptrace();
0f80bc85
JD
328
329 /* Need to check this early because mmapping happens before the
330 * kernel is running.
331 */
332 check_tmpexec();
576c013d
JD
333
334 pid = start_ptraced_child();
335 if (init_registers(pid))
336 fatal("Failed to initialize default registers");
337 stop_ptraced_child(pid, 1, 1);
1da177e4
LT
338}
339
0f80bc85
JD
340int __init parse_iomem(char *str, int *add)
341{
342 struct iomem_region *new;
73c8f444 343 struct stat64 buf;
0f80bc85 344 char *file, *driver;
73c8f444 345 int fd, size;
0f80bc85
JD
346
347 driver = str;
348 file = strchr(str,',');
ba180fd4 349 if (file == NULL) {
626c59f5 350 fprintf(stderr, "parse_iomem : failed to parse iomem\n");
0f80bc85
JD
351 goto out;
352 }
353 *file = '\0';
354 file++;
73c8f444 355 fd = open(file, O_RDWR, 0);
ba180fd4 356 if (fd < 0) {
512b6fb1 357 perror("parse_iomem - Couldn't open io file");
0f80bc85
JD
358 goto out;
359 }
360
ba180fd4 361 if (fstat64(fd, &buf) < 0) {
73c8f444 362 perror("parse_iomem - cannot stat_fd file");
0f80bc85
JD
363 goto out_close;
364 }
365
366 new = malloc(sizeof(*new));
ba180fd4 367 if (new == NULL) {
0f80bc85
JD
368 perror("Couldn't allocate iomem_region struct");
369 goto out_close;
370 }
371
73c8f444 372 size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
0f80bc85
JD
373
374 *new = ((struct iomem_region) { .next = iomem_regions,
375 .driver = driver,
376 .fd = fd,
377 .size = size,
378 .phys = 0,
379 .virt = 0 });
380 iomem_regions = new;
381 iomem_size += new->size + UM_KERN_PAGE_SIZE;
382
9eae9b13 383 return 0;
0f80bc85 384 out_close:
73c8f444 385 close(fd);
0f80bc85 386 out:
9eae9b13 387 return 1;
0f80bc85 388}
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