2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
17 #include <asm/unistd.h>
19 #include "user_util.h"
20 #include "kern_util.h"
23 #include "signal_kern.h"
24 #include "signal_user.h"
25 #include "sysdep/ptrace.h"
26 #include "sysdep/sigcontext.h"
28 #include "ptrace_user.h"
29 #include "time_user.h"
32 #include "uml-config.h"
33 #include "choose-mode.h"
35 #ifdef UML_CONFIG_MODE_SKAS
37 #include "skas_ptrace.h"
38 #include "registers.h"
41 void init_new_thread_stack(void *sig_stack
, void (*usr1_handler
)(int))
45 if(sig_stack
!= NULL
){
46 pages
= (1 << UML_CONFIG_KERNEL_STACK_ORDER
);
47 set_sigstack(sig_stack
, pages
* page_size());
50 if(usr1_handler
) set_handler(SIGUSR1
, usr1_handler
, flags
, -1);
53 void init_new_thread_signals(int altstack
)
55 int flags
= altstack
? SA_ONSTACK
: 0;
57 set_handler(SIGSEGV
, (__sighandler_t
) sig_handler
, flags
,
58 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
59 set_handler(SIGTRAP
, (__sighandler_t
) sig_handler
, flags
,
60 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
61 set_handler(SIGFPE
, (__sighandler_t
) sig_handler
, flags
,
62 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
63 set_handler(SIGILL
, (__sighandler_t
) sig_handler
, flags
,
64 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
65 set_handler(SIGBUS
, (__sighandler_t
) sig_handler
, flags
,
66 SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
67 set_handler(SIGUSR2
, (__sighandler_t
) sig_handler
,
68 flags
, SIGUSR1
, SIGIO
, SIGWINCH
, SIGALRM
, SIGVTALRM
, -1);
69 signal(SIGHUP
, SIG_IGN
);
71 init_irq_signals(altstack
);
77 unsigned long temp_stack
;
82 /* See above for why sigkill is here */
84 int sigkill
= SIGKILL
;
86 int outer_tramp(void *arg
)
92 t
->pid
= clone(t
->tramp
, (void *) t
->temp_stack
+ page_size()/2,
93 t
->flags
, t
->tramp_data
);
94 if(t
->pid
> 0) wait_for_stop(t
->pid
, SIGSTOP
, PTRACE_CONT
, NULL
);
95 kill(os_getpid(), sig
);
99 int start_fork_tramp(void *thread_arg
, unsigned long temp_stack
,
100 int clone_flags
, int (*tramp
)(void *))
104 int new_pid
, status
, err
;
106 /* The trampoline will run on the temporary stack */
107 sp
= stack_sp(temp_stack
);
109 clone_flags
|= CLONE_FILES
| SIGCHLD
;
112 arg
.tramp_data
= thread_arg
;
113 arg
.temp_stack
= temp_stack
;
114 arg
.flags
= clone_flags
;
116 /* Start the process and wait for it to kill itself */
117 new_pid
= clone(outer_tramp
, (void *) sp
, clone_flags
, &arg
);
121 CATCH_EINTR(err
= waitpid(new_pid
, &status
, 0));
123 panic("Waiting for outer trampoline failed - errno = %d",
126 if(!WIFSIGNALED(status
) || (WTERMSIG(status
) != SIGKILL
))
127 panic("outer trampoline didn't exit with SIGKILL, "
128 "status = %d", status
);
133 static int ptrace_child(void)
136 int pid
= os_getpid(), ppid
= getppid();
139 if(ptrace(PTRACE_TRACEME
, 0, 0, 0) < 0){
141 os_kill_process(pid
, 0);
143 os_stop_process(pid
);
145 /*This syscall will be intercepted by the parent. Don't call more than
147 sc_result
= os_getpid();
149 if (sc_result
== pid
)
150 ret
= 1; /*Nothing modified by the parent, we are running
152 else if (sc_result
== ppid
)
153 ret
= 0; /*Expected in check_ptrace and check_sysemu when they
154 succeed in modifying the stack frame*/
156 ret
= 2; /*Serious trouble! This could be caused by a bug in
157 host 2.6 SKAS3/2.6 patch before release -V6, together
158 with a bug in the UML code itself.*/
162 static int start_ptraced_child(void)
171 panic("check_ptrace : fork failed, errno = %d", errno
);
172 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
174 panic("check_ptrace : wait failed, errno = %d", errno
);
175 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGSTOP
))
176 panic("check_ptrace : expected SIGSTOP, got status = %d",
182 /* When testing for SYSEMU support, if it is one of the broken versions, we must
183 * just avoid using sysemu, not panic, but only if SYSEMU features are broken.
184 * So only for SYSEMU features we test mustpanic, while normal host features
185 * must work anyway!*/
186 static int stop_ptraced_child(int pid
, int exitcode
, int mustexit
)
188 int status
, n
, ret
= 0;
190 if(ptrace(PTRACE_CONT
, pid
, 0, 0) < 0)
191 panic("stop_ptraced_child : ptrace failed, errno = %d", errno
);
192 CATCH_EINTR(n
= waitpid(pid
, &status
, 0));
193 if(!WIFEXITED(status
) || (WEXITSTATUS(status
) != exitcode
)) {
194 int exit_with
= WEXITSTATUS(status
);
196 printk("check_ptrace : child exited with status 2. "
197 "Serious trouble happening! Try updating your "
198 "host skas patch!\nDisabling SYSEMU support.");
199 printk("check_ptrace : child exited with exitcode %d, while "
200 "expecting %d; status 0x%x", exit_with
,
212 static int force_sysemu_disabled
= 0;
214 static int __init
nosysemu_cmd_param(char *str
, int* add
)
216 force_sysemu_disabled
= 1;
220 __uml_setup("nosysemu", nosysemu_cmd_param
,
222 " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
223 " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
224 " behaviour of ptrace() and helps reducing host context switch rate.\n"
225 " To make it working, you need a kernel patch for your host, too.\n"
226 " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
228 static void __init
check_sysemu(void)
230 int pid
, syscall
, n
, status
, count
=0;
232 printk("Checking syscall emulation patch for ptrace...");
233 sysemu_supported
= 0;
234 pid
= start_ptraced_child();
236 if(ptrace(PTRACE_SYSEMU
, pid
, 0, 0) < 0)
239 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
241 panic("check_sysemu : wait failed, errno = %d", errno
);
242 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
))
243 panic("check_sysemu : expected SIGTRAP, "
244 "got status = %d", status
);
246 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_RET_OFFSET
,
249 panic("check_sysemu : failed to modify system "
250 "call return, errno = %d", errno
);
252 if (stop_ptraced_child(pid
, 0, 0) < 0)
255 sysemu_supported
= 1;
257 set_using_sysemu(!force_sysemu_disabled
);
259 printk("Checking advanced syscall emulation patch for ptrace...");
260 pid
= start_ptraced_child();
263 if(ptrace(PTRACE_SYSEMU_SINGLESTEP
, pid
, 0, 0) < 0)
265 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
267 panic("check_ptrace : wait failed, errno = %d", errno
);
268 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
))
269 panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
270 "got status = %d", status
);
272 syscall
= ptrace(PTRACE_PEEKUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
274 if(syscall
== __NR_getpid
){
276 panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
277 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_RET_OFFSET
,
280 panic("check_sysemu : failed to modify system "
281 "call return, errno = %d", errno
);
285 if (stop_ptraced_child(pid
, 0, 0) < 0)
288 sysemu_supported
= 2;
291 if ( !force_sysemu_disabled
)
292 set_using_sysemu(sysemu_supported
);
296 stop_ptraced_child(pid
, 1, 0);
301 void __init
check_ptrace(void)
303 int pid
, syscall
, n
, status
;
305 printk("Checking that ptrace can change system call numbers...");
306 pid
= start_ptraced_child();
308 if (ptrace(PTRACE_OLDSETOPTIONS
, pid
, 0, (void *)PTRACE_O_TRACESYSGOOD
) < 0)
309 panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno
);
312 if(ptrace(PTRACE_SYSCALL
, pid
, 0, 0) < 0)
313 panic("check_ptrace : ptrace failed, errno = %d",
315 CATCH_EINTR(n
= waitpid(pid
, &status
, WUNTRACED
));
317 panic("check_ptrace : wait failed, errno = %d", errno
);
318 if(!WIFSTOPPED(status
) || (WSTOPSIG(status
) != SIGTRAP
+ 0x80))
319 panic("check_ptrace : expected SIGTRAP + 0x80, "
320 "got status = %d", status
);
322 syscall
= ptrace(PTRACE_PEEKUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
324 if(syscall
== __NR_getpid
){
325 n
= ptrace(PTRACE_POKEUSR
, pid
, PT_SYSCALL_NR_OFFSET
,
328 panic("check_ptrace : failed to modify system "
329 "call, errno = %d", errno
);
333 stop_ptraced_child(pid
, 0, 1);
338 int run_kernel_thread(int (*fn
)(void *), void *arg
, void **jmp_ptr
)
344 n
= sigsetjmp(buf
, 1);
351 void forward_pending_sigio(int target
)
355 if(sigpending(&sigs
))
356 panic("forward_pending_sigio : sigpending failed");
357 if(sigismember(&sigs
, SIGIO
))
361 #ifdef UML_CONFIG_MODE_SKAS
362 static inline int check_skas3_ptrace_support(void)
364 struct ptrace_faultinfo fi
;
367 printf("Checking for the skas3 patch in the host...");
368 pid
= start_ptraced_child();
370 n
= ptrace(PTRACE_FAULTINFO
, pid
, 0, &fi
);
373 printf("not found\n");
383 stop_ptraced_child(pid
, 1, 1);
388 int can_do_skas(void)
392 printf("Checking for /proc/mm...");
393 if (os_access("/proc/mm", OS_ACC_W_OK
) < 0) {
394 printf("not found\n");
401 ret
= check_skas3_ptrace_support();
406 int can_do_skas(void)