[TG3]: Set minimal hw interrupt mitigation.
[linux-2.6/verdex.git] / arch / um / kernel / process.c
blob51f8e5a8ac6a9d60357888e56462f18f6b2ff93e
1 /*
2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 */
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <signal.h>
9 #include <sched.h>
10 #include <errno.h>
11 #include <stdarg.h>
12 #include <stdlib.h>
13 #include <setjmp.h>
14 #include <sys/time.h>
15 #include <sys/wait.h>
16 #include <sys/mman.h>
17 #include <asm/unistd.h>
18 #include <asm/page.h>
19 #include "user_util.h"
20 #include "kern_util.h"
21 #include "user.h"
22 #include "process.h"
23 #include "signal_kern.h"
24 #include "signal_user.h"
25 #include "sysdep/ptrace.h"
26 #include "sysdep/sigcontext.h"
27 #include "irq_user.h"
28 #include "ptrace_user.h"
29 #include "time_user.h"
30 #include "init.h"
31 #include "os.h"
32 #include "uml-config.h"
33 #include "ptrace_user.h"
34 #include "choose-mode.h"
35 #include "mode.h"
36 #ifdef UML_CONFIG_MODE_SKAS
37 #include "skas.h"
38 #include "skas_ptrace.h"
39 #include "registers.h"
40 #endif
42 void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
44 int flags = 0, pages;
46 if(sig_stack != NULL){
47 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
48 set_sigstack(sig_stack, pages * page_size());
49 flags = SA_ONSTACK;
51 if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1);
54 void init_new_thread_signals(int altstack)
56 int flags = altstack ? SA_ONSTACK : 0;
58 set_handler(SIGSEGV, (__sighandler_t) sig_handler, flags,
59 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
60 set_handler(SIGTRAP, (__sighandler_t) sig_handler, flags,
61 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
62 set_handler(SIGFPE, (__sighandler_t) sig_handler, flags,
63 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
64 set_handler(SIGILL, (__sighandler_t) sig_handler, flags,
65 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
66 set_handler(SIGBUS, (__sighandler_t) sig_handler, flags,
67 SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
68 set_handler(SIGUSR2, (__sighandler_t) sig_handler,
69 flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
70 signal(SIGHUP, SIG_IGN);
72 init_irq_signals(altstack);
75 struct tramp {
76 int (*tramp)(void *);
77 void *tramp_data;
78 unsigned long temp_stack;
79 int flags;
80 int pid;
83 /* See above for why sigkill is here */
85 int sigkill = SIGKILL;
87 int outer_tramp(void *arg)
89 struct tramp *t;
90 int sig = sigkill;
92 t = arg;
93 t->pid = clone(t->tramp, (void *) t->temp_stack + page_size()/2,
94 t->flags, t->tramp_data);
95 if(t->pid > 0) wait_for_stop(t->pid, SIGSTOP, PTRACE_CONT, NULL);
96 kill(os_getpid(), sig);
97 _exit(0);
100 int start_fork_tramp(void *thread_arg, unsigned long temp_stack,
101 int clone_flags, int (*tramp)(void *))
103 struct tramp arg;
104 unsigned long sp;
105 int new_pid, status, err;
107 /* The trampoline will run on the temporary stack */
108 sp = stack_sp(temp_stack);
110 clone_flags |= CLONE_FILES | SIGCHLD;
112 arg.tramp = tramp;
113 arg.tramp_data = thread_arg;
114 arg.temp_stack = temp_stack;
115 arg.flags = clone_flags;
117 /* Start the process and wait for it to kill itself */
118 new_pid = clone(outer_tramp, (void *) sp, clone_flags, &arg);
119 if(new_pid < 0)
120 return(new_pid);
122 CATCH_EINTR(err = waitpid(new_pid, &status, 0));
123 if(err < 0)
124 panic("Waiting for outer trampoline failed - errno = %d",
125 errno);
127 if(!WIFSIGNALED(status) || (WTERMSIG(status) != SIGKILL))
128 panic("outer trampoline didn't exit with SIGKILL, "
129 "status = %d", status);
131 return(arg.pid);
134 static int ptrace_child(void *arg)
136 int ret;
137 int pid = os_getpid(), ppid = getppid();
138 int sc_result;
140 if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
141 perror("ptrace");
142 os_kill_process(pid, 0);
144 os_stop_process(pid);
146 /*This syscall will be intercepted by the parent. Don't call more than
147 * once, please.*/
148 sc_result = os_getpid();
150 if (sc_result == pid)
151 ret = 1; /*Nothing modified by the parent, we are running
152 normally.*/
153 else if (sc_result == ppid)
154 ret = 0; /*Expected in check_ptrace and check_sysemu when they
155 succeed in modifying the stack frame*/
156 else
157 ret = 2; /*Serious trouble! This could be caused by a bug in
158 host 2.6 SKAS3/2.6 patch before release -V6, together
159 with a bug in the UML code itself.*/
160 _exit(ret);
163 static int start_ptraced_child(void **stack_out)
165 void *stack;
166 unsigned long sp;
167 int pid, n, status;
169 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
170 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
171 if(stack == MAP_FAILED)
172 panic("check_ptrace : mmap failed, errno = %d", errno);
173 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
174 pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
175 if(pid < 0)
176 panic("check_ptrace : clone failed, errno = %d", errno);
177 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
178 if(n < 0)
179 panic("check_ptrace : wait failed, errno = %d", errno);
180 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
181 panic("check_ptrace : expected SIGSTOP, got status = %d",
182 status);
184 *stack_out = stack;
185 return(pid);
188 /* When testing for SYSEMU support, if it is one of the broken versions, we must
189 * just avoid using sysemu, not panic, but only if SYSEMU features are broken.
190 * So only for SYSEMU features we test mustpanic, while normal host features
191 * must work anyway!*/
192 static int stop_ptraced_child(int pid, void *stack, int exitcode, int mustpanic)
194 int status, n, ret = 0;
196 if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
197 panic("check_ptrace : ptrace failed, errno = %d", errno);
198 CATCH_EINTR(n = waitpid(pid, &status, 0));
199 if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
200 int exit_with = WEXITSTATUS(status);
201 if (exit_with == 2)
202 printk("check_ptrace : child exited with status 2. "
203 "Serious trouble happening! Try updating your "
204 "host skas patch!\nDisabling SYSEMU support.");
205 printk("check_ptrace : child exited with exitcode %d, while "
206 "expecting %d; status 0x%x", exit_with,
207 exitcode, status);
208 if (mustpanic)
209 panic("\n");
210 else
211 printk("\n");
212 ret = -1;
215 if(munmap(stack, PAGE_SIZE) < 0)
216 panic("check_ptrace : munmap failed, errno = %d", errno);
217 return ret;
220 static int force_sysemu_disabled = 0;
222 static int __init nosysemu_cmd_param(char *str, int* add)
224 force_sysemu_disabled = 1;
225 return 0;
228 __uml_setup("nosysemu", nosysemu_cmd_param,
229 "nosysemu\n"
230 " Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
231 " SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
232 " behaviour of ptrace() and helps reducing host context switch rate.\n"
233 " To make it working, you need a kernel patch for your host, too.\n"
234 " See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
236 static void __init check_sysemu(void)
238 void *stack;
239 int pid, syscall, n, status, count=0;
241 printk("Checking syscall emulation patch for ptrace...");
242 sysemu_supported = 0;
243 pid = start_ptraced_child(&stack);
245 if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
246 goto fail;
248 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
249 if (n < 0)
250 panic("check_sysemu : wait failed, errno = %d", errno);
251 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
252 panic("check_sysemu : expected SIGTRAP, "
253 "got status = %d", status);
255 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
256 os_getpid());
257 if(n < 0)
258 panic("check_sysemu : failed to modify system "
259 "call return, errno = %d", errno);
261 if (stop_ptraced_child(pid, stack, 0, 0) < 0)
262 goto fail_stopped;
264 sysemu_supported = 1;
265 printk("OK\n");
266 set_using_sysemu(!force_sysemu_disabled);
268 printk("Checking advanced syscall emulation patch for ptrace...");
269 pid = start_ptraced_child(&stack);
270 while(1){
271 count++;
272 if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
273 goto fail;
274 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
275 if(n < 0)
276 panic("check_ptrace : wait failed, errno = %d", errno);
277 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
278 panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
279 "got status = %d", status);
281 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
283 if(syscall == __NR_getpid){
284 if (!count)
285 panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
286 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
287 os_getpid());
288 if(n < 0)
289 panic("check_sysemu : failed to modify system "
290 "call return, errno = %d", errno);
291 break;
294 if (stop_ptraced_child(pid, stack, 0, 0) < 0)
295 goto fail_stopped;
297 sysemu_supported = 2;
298 printk("OK\n");
300 if ( !force_sysemu_disabled )
301 set_using_sysemu(sysemu_supported);
302 return;
304 fail:
305 stop_ptraced_child(pid, stack, 1, 0);
306 fail_stopped:
307 printk("missing\n");
310 void __init check_ptrace(void)
312 void *stack;
313 int pid, syscall, n, status;
315 printk("Checking that ptrace can change system call numbers...");
316 pid = start_ptraced_child(&stack);
318 if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
319 panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno);
321 while(1){
322 if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
323 panic("check_ptrace : ptrace failed, errno = %d",
324 errno);
325 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
326 if(n < 0)
327 panic("check_ptrace : wait failed, errno = %d", errno);
328 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80))
329 panic("check_ptrace : expected SIGTRAP + 0x80, "
330 "got status = %d", status);
332 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
334 if(syscall == __NR_getpid){
335 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
336 __NR_getppid);
337 if(n < 0)
338 panic("check_ptrace : failed to modify system "
339 "call, errno = %d", errno);
340 break;
343 stop_ptraced_child(pid, stack, 0, 1);
344 printk("OK\n");
345 check_sysemu();
348 int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
350 sigjmp_buf buf;
351 int n;
353 *jmp_ptr = &buf;
354 n = sigsetjmp(buf, 1);
355 if(n != 0)
356 return(n);
357 (*fn)(arg);
358 return(0);
361 void forward_pending_sigio(int target)
363 sigset_t sigs;
365 if(sigpending(&sigs))
366 panic("forward_pending_sigio : sigpending failed");
367 if(sigismember(&sigs, SIGIO))
368 kill(target, SIGIO);
371 #ifdef UML_CONFIG_MODE_SKAS
372 static inline int check_skas3_ptrace_support(void)
374 struct ptrace_faultinfo fi;
375 void *stack;
376 int pid, n, ret = 1;
378 printf("Checking for the skas3 patch in the host...");
379 pid = start_ptraced_child(&stack);
381 n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
382 if (n < 0) {
383 if(errno == EIO)
384 printf("not found\n");
385 else {
386 perror("not found");
388 ret = 0;
389 } else {
390 printf("found\n");
393 init_registers(pid);
394 stop_ptraced_child(pid, stack, 1, 1);
396 return(ret);
399 int can_do_skas(void)
401 int ret = 1;
403 printf("Checking for /proc/mm...");
404 if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
405 printf("not found\n");
406 ret = 0;
407 goto out;
408 } else {
409 printf("found\n");
412 ret = check_skas3_ptrace_support();
413 out:
414 return ret;
416 #else
417 int can_do_skas(void)
419 return(0);
421 #endif