2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
19 #include <sys/resource.h>
20 #include <asm/unistd.h>
24 #include <ptrace_user.h>
25 #include <registers.h>
28 static void ptrace_child(void)
31 /* Calling os_getpid because some libcs cached getpid incorrectly */
32 int pid = os_getpid(), ppid = getppid();
35 if (change_sig(SIGWINCH, 0) < 0 ||
36 ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
43 * This syscall will be intercepted by the parent. Don't call more than
46 sc_result = os_getpid();
49 /* Nothing modified by the parent, we are running normally. */
51 else if (sc_result == ppid)
53 * Expected in check_ptrace and check_sysemu when they succeed
54 * in modifying the stack frame
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.
67 static void fatal_perror(const char *str)
73 static void fatal(char *fmt, ...)
78 vfprintf(stderr, fmt, list);
84 static void non_fatal(char *fmt, ...)
89 vfprintf(stderr, fmt, list);
93 static int start_ptraced_child(void)
101 fatal_perror("start_ptraced_child : fork failed");
103 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
105 fatal_perror("check_ptrace : waitpid failed");
106 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
107 fatal("check_ptrace : expected SIGSTOP, got status = %d",
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
116 * So only for SYSEMU features we test mustpanic, while normal host features
119 static int stop_ptraced_child(int pid, int exitcode, int mustexit)
121 int status, n, ret = 0;
123 if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
124 perror("stop_ptraced_child : ptrace failed");
127 CATCH_EINTR(n = waitpid(pid, &status, 0));
128 if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
129 int exit_with = WEXITSTATUS(status);
131 non_fatal("check_ptrace : child exited with status 2. "
132 "\nDisabling SYSEMU support.\n");
133 non_fatal("check_ptrace : child exited with exitcode %d, while "
134 "expecting %d; status 0x%x\n", exit_with,
144 /* Changed only during early boot */
145 static int force_sysemu_disabled = 0;
147 static int __init nosysemu_cmd_param(char *str, int* add)
149 force_sysemu_disabled = 1;
153 __uml_setup("nosysemu", nosysemu_cmd_param,
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");
162 static void __init check_sysemu(void)
164 unsigned long regs[MAX_REG_NR];
165 int pid, n, status, count=0;
167 non_fatal("Checking syscall emulation patch for ptrace...");
168 sysemu_supported = 0;
169 pid = start_ptraced_child();
171 if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
174 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
176 fatal_perror("check_sysemu : wait failed");
177 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
178 fatal("check_sysemu : expected SIGTRAP, got status = %d\n",
181 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
182 fatal_perror("check_sysemu : PTRACE_GETREGS failed");
183 if (PT_SYSCALL_NR(regs) != __NR_getpid) {
184 non_fatal("check_sysemu got system call number %d, "
185 "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
189 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
191 non_fatal("check_sysemu : failed to modify system call "
196 if (stop_ptraced_child(pid, 0, 0) < 0)
199 sysemu_supported = 1;
201 set_using_sysemu(!force_sysemu_disabled);
203 non_fatal("Checking advanced syscall emulation patch for ptrace...");
204 pid = start_ptraced_child();
206 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
207 (void *) PTRACE_O_TRACESYSGOOD) < 0))
208 fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed");
212 if (ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
214 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
216 fatal_perror("check_sysemu: wait failed");
218 if (WIFSTOPPED(status) &&
219 (WSTOPSIG(status) == (SIGTRAP|0x80))) {
221 non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
222 "doesn't singlestep");
225 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET,
228 fatal_perror("check_sysemu : failed to modify "
229 "system call return");
232 else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
235 non_fatal("check_sysemu: expected SIGTRAP or "
236 "(SIGTRAP | 0x80), got status = %d\n",
241 if (stop_ptraced_child(pid, 0, 0) < 0)
244 sysemu_supported = 2;
247 if (!force_sysemu_disabled)
248 set_using_sysemu(sysemu_supported);
252 stop_ptraced_child(pid, 1, 0);
254 non_fatal("missing\n");
257 static void __init check_ptrace(void)
259 int pid, syscall, n, status;
261 non_fatal("Checking that ptrace can change system call numbers...");
262 pid = start_ptraced_child();
264 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
265 (void *) PTRACE_O_TRACESYSGOOD) < 0))
266 fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
269 if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
270 fatal_perror("check_ptrace : ptrace failed");
272 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
274 fatal_perror("check_ptrace : wait failed");
276 if (!WIFSTOPPED(status) ||
277 (WSTOPSIG(status) != (SIGTRAP | 0x80)))
278 fatal("check_ptrace : expected (SIGTRAP|0x80), "
279 "got status = %d", status);
281 syscall = ptrace(PTRACE_PEEKUSER, pid, PT_SYSCALL_NR_OFFSET,
283 if (syscall == __NR_getpid) {
284 n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
287 fatal_perror("check_ptrace : failed to modify "
292 stop_ptraced_child(pid, 0, 1);
297 extern void check_tmpexec(void);
299 static void __init check_coredump_limit(void)
302 int err = getrlimit(RLIMIT_CORE, &lim);
305 perror("Getting core dump limit");
309 printf("Core dump limits :\n\tsoft - ");
310 if (lim.rlim_cur == RLIM_INFINITY)
312 else printf("%lu\n", lim.rlim_cur);
315 if (lim.rlim_max == RLIM_INFINITY)
317 else printf("%lu\n", lim.rlim_max);
320 void __init os_early_checks(void)
324 /* Print out the core dump limits early */
325 check_coredump_limit();
329 /* Need to check this early because mmapping happens before the
334 pid = start_ptraced_child();
335 if (init_registers(pid))
336 fatal("Failed to initialize default registers");
337 stop_ptraced_child(pid, 1, 1);
340 int __init parse_iomem(char *str, int *add)
342 struct iomem_region *new;
348 file = strchr(str,',');
350 fprintf(stderr, "parse_iomem : failed to parse iomem\n");
355 fd = open(file, O_RDWR, 0);
357 perror("parse_iomem - Couldn't open io file");
361 if (fstat64(fd, &buf) < 0) {
362 perror("parse_iomem - cannot stat_fd file");
366 new = malloc(sizeof(*new));
368 perror("Couldn't allocate iomem_region struct");
372 size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
374 *new = ((struct iomem_region) { .next = iomem_regions,
381 iomem_size += new->size + UM_KERN_PAGE_SIZE;