2 * Copyright (C) 2002- 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
12 #include <sys/ptrace.h>
14 #include <asm/unistd.h>
15 #include "as-layout.h"
16 #include "chan_user.h"
17 #include "kern_constants.h"
22 #include "ptrace_user.h"
23 #include "registers.h"
25 #include "skas_ptrace.h"
27 #include "sysdep/stub.h"
29 int is_skas_winch(int pid, int fd, void *data)
34 register_winch_irq(-1, fd, -1, data, 0);
38 static int ptrace_dump_regs(int pid)
40 unsigned long regs[MAX_REG_NR];
43 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
46 printk(UM_KERN_ERR "Stub registers -\n");
47 for (i = 0; i < ARRAY_SIZE(regs); i++)
48 printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]);
54 * Signals that are OK to receive in the stub - we'll just continue it.
55 * SIGWINCH will happen when UML is inside a detached screen.
57 #define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
59 /* Signals that the stub will finish with - anything else is an error */
60 #define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
62 void wait_stub_done(int pid)
67 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
68 if ((n < 0) || !WIFSTOPPED(status))
71 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
74 err = ptrace(PTRACE_CONT, pid, 0, 0);
76 panic("wait_stub_done : continue failed, errno = %d\n",
80 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
84 err = ptrace_dump_regs(pid);
86 printk(UM_KERN_ERR "Failed to get registers from stub, "
87 "errno = %d\n", -err);
88 panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
89 "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
92 extern unsigned long current_stub_stack(void);
94 void get_skas_faultinfo(int pid, struct faultinfo * fi)
98 if (ptrace_faultinfo) {
99 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
101 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
102 "errno = %d\n", errno);
104 /* Special handling for i386, which has different structs */
105 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
106 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
107 sizeof(struct faultinfo) -
108 sizeof(struct ptrace_faultinfo));
111 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
113 panic("Failed to continue stub, pid = %d, errno = %d\n",
118 * faultinfo is prepared by the stub-segv-handler at start of
119 * the stub stack page. We just have to copy it.
121 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
125 static void handle_segv(int pid, struct uml_pt_regs * regs)
127 get_skas_faultinfo(pid, ®s->faultinfo);
128 segv(regs->faultinfo, 0, 1, NULL);
132 * To use the same value of using_sysemu as the caller, ask it that value
133 * (in local_using_sysemu
135 static void handle_trap(int pid, struct uml_pt_regs *regs,
136 int local_using_sysemu)
140 /* Mark this as a syscall */
141 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp);
143 if (!local_using_sysemu)
145 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
148 panic("handle_trap - nullifying syscall failed, "
149 "errno = %d\n", errno);
151 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
153 panic("handle_trap - continuing to end of syscall "
154 "failed, errno = %d\n", errno);
156 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
157 if ((err < 0) || !WIFSTOPPED(status) ||
158 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
159 err = ptrace_dump_regs(pid);
161 printk(UM_KERN_ERR "Failed to get registers "
162 "from process, errno = %d\n", -err);
163 panic("handle_trap - failed to wait at end of syscall, "
164 "errno = %d, status = %d\n", errno, status);
168 handle_syscall(regs);
171 extern int __syscall_stub_start;
173 static int userspace_tramp(void *stack)
178 ptrace(PTRACE_TRACEME, 0, 0, 0);
180 init_new_thread_signals();
181 err = set_interval(1);
183 panic("userspace_tramp - setting timer failed, errno = %d\n",
188 * This has a pte, but it can't be mapped in with the usual
189 * tlb_flush mechanism because this is part of that mechanism
192 unsigned long long offset;
193 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
194 addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE,
195 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
196 if (addr == MAP_FAILED) {
197 printk(UM_KERN_ERR "mapping mmap stub failed, "
198 "errno = %d\n", errno);
203 fd = phys_mapping(to_phys(stack), &offset);
204 addr = mmap((void *) UML_CONFIG_STUB_DATA,
205 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
206 MAP_FIXED | MAP_SHARED, fd, offset);
207 if (addr == MAP_FAILED) {
208 printk(UM_KERN_ERR "mapping segfault stack "
209 "failed, errno = %d\n", errno);
214 if (!ptrace_faultinfo && (stack != NULL)) {
217 unsigned long v = UML_CONFIG_STUB_CODE +
218 (unsigned long) stub_segv_handler -
219 (unsigned long) &__syscall_stub_start;
221 set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE);
222 sigemptyset(&sa.sa_mask);
223 sigaddset(&sa.sa_mask, SIGIO);
224 sigaddset(&sa.sa_mask, SIGWINCH);
225 sigaddset(&sa.sa_mask, SIGALRM);
226 sigaddset(&sa.sa_mask, SIGVTALRM);
227 sigaddset(&sa.sa_mask, SIGUSR1);
228 sa.sa_flags = SA_ONSTACK;
229 sa.sa_handler = (void *) v;
230 sa.sa_restorer = NULL;
231 if (sigaction(SIGSEGV, &sa, NULL) < 0)
232 panic("userspace_tramp - setting SIGSEGV handler "
233 "failed - errno = %d\n", errno);
236 kill(os_getpid(), SIGSTOP);
240 /* Each element set once, and only accessed by a single processor anyway */
243 int userspace_pid[NR_CPUS];
245 int start_userspace(unsigned long stub_stack)
249 int pid, status, n, flags;
251 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
252 PROT_READ | PROT_WRITE | PROT_EXEC,
253 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
254 if (stack == MAP_FAILED)
255 panic("start_userspace : mmap failed, errno = %d", errno);
256 sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
258 flags = CLONE_FILES | SIGCHLD;
262 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
264 panic("start_userspace : clone failed, errno = %d", errno);
267 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
269 panic("start_userspace : wait failed, errno = %d",
271 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
273 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
274 panic("start_userspace : expected SIGSTOP, got status = %d",
277 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
278 (void *) PTRACE_O_TRACESYSGOOD) < 0)
279 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, "
280 "errno = %d\n", errno);
282 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0)
283 panic("start_userspace : munmap failed, errno = %d\n", errno);
288 void userspace(struct uml_pt_regs *regs)
290 int err, status, op, pid = userspace_pid[0];
291 /* To prevent races if using_sysemu changes under us.*/
292 int local_using_sysemu;
295 restore_registers(pid, regs);
297 /* Now we set local_using_sysemu to be used for one loop */
298 local_using_sysemu = get_using_sysemu();
300 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
301 singlestepping(NULL));
303 err = ptrace(op, pid, 0, 0);
305 panic("userspace - could not resume userspace process, "
306 "pid=%d, ptrace operation = %d, errno = %d\n",
309 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
311 panic("userspace - waitpid failed, errno = %d\n",
315 save_registers(pid, regs);
316 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
318 if (WIFSTOPPED(status)) {
319 int sig = WSTOPSIG(status);
322 if (PTRACE_FULL_FAULTINFO ||
324 get_skas_faultinfo(pid,
326 (*sig_info[SIGSEGV])(SIGSEGV, regs);
328 else handle_segv(pid, regs);
331 handle_trap(pid, regs, local_using_sysemu);
334 relay_signal(SIGTRAP, regs);
343 (*sig_info[sig])(sig, regs);
347 printk(UM_KERN_ERR "userspace - child stopped "
348 "with signal %d\n", sig);
350 pid = userspace_pid[0];
353 /* Avoid -ERESTARTSYS handling in host */
354 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
355 PT_SYSCALL_NR(regs->gp) = -1;
360 static unsigned long thread_regs[MAX_REG_NR];
362 static int __init init_thread_regs(void)
364 get_safe_registers(thread_regs);
365 /* Set parent's instruction pointer to start of clone-stub */
366 thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
367 (unsigned long) stub_clone_handler -
368 (unsigned long) &__syscall_stub_start;
369 thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE -
371 #ifdef __SIGNAL_FRAMESIZE
372 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
377 __initcall(init_thread_regs);
379 int copy_context_skas0(unsigned long new_stack, int pid)
382 unsigned long current_stack = current_stub_stack();
383 struct stub_data *data = (struct stub_data *) current_stack;
384 struct stub_data *child_data = (struct stub_data *) new_stack;
385 unsigned long long new_offset;
386 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
389 * prepare offset and fd of child's stack as argument for parent's
390 * and child's mmap2 calls
392 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
394 .timer = ((struct itimerval)
395 { { 0, 1000000 / hz() },
396 { 0, 1000000 / hz() }})});
397 err = ptrace_setregs(pid, thread_regs);
399 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
400 "pid = %d, errno = %d\n", pid, -err);
402 /* set a well known return code for detection of child write failure */
403 child_data->err = 12345678;
406 * Wait, until parent has finished its work: read child's pid from
407 * parent's stack, and check, if bad result.
409 err = ptrace(PTRACE_CONT, pid, 0, 0);
411 panic("Failed to continue new process, pid = %d, "
412 "errno = %d\n", pid, errno);
417 panic("copy_context_skas0 - stub-parent reports error %d\n",
421 * Wait, until child has finished too: read child's result from
422 * child's stack and check it.
425 if (child_data->err != UML_CONFIG_STUB_DATA)
426 panic("copy_context_skas0 - stub-child reports error %ld\n",
429 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
430 (void *)PTRACE_O_TRACESYSGOOD) < 0)
431 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
432 "errno = %d\n", errno);
438 * This is used only, if stub pages are needed, while proc_mm is
439 * available. Opening /proc/mm creates a new mm_context, which lacks
440 * the stub-pages. Thus, we map them using /proc/mm-fd
442 void map_stub_pages(int fd, unsigned long code,
443 unsigned long data, unsigned long stack)
445 struct proc_mm_op mmop;
447 unsigned long long code_offset;
448 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
451 mmop = ((struct proc_mm_op) { .op = MM_MMAP,
455 .len = UM_KERN_PAGE_SIZE,
457 .flags = MAP_FIXED | MAP_PRIVATE,
459 .offset = code_offset
461 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
462 if (n != sizeof(mmop)) {
464 printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, "
465 "offset = %llx\n", code, code_fd,
466 (unsigned long long) code_offset);
467 panic("map_stub_pages : /proc/mm map for code failed, "
472 unsigned long long map_offset;
473 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
474 mmop = ((struct proc_mm_op)
479 .len = UM_KERN_PAGE_SIZE,
480 .prot = PROT_READ | PROT_WRITE,
481 .flags = MAP_FIXED | MAP_SHARED,
485 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
486 if (n != sizeof(mmop))
487 panic("map_stub_pages : /proc/mm map for data failed, "
488 "err = %d\n", errno);
492 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
494 (*buf)[0].JB_IP = (unsigned long) handler;
495 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
499 #define INIT_JMP_NEW_THREAD 0
500 #define INIT_JMP_CALLBACK 1
501 #define INIT_JMP_HALT 2
502 #define INIT_JMP_REBOOT 3
504 void switch_threads(jmp_buf *me, jmp_buf *you)
506 if (UML_SETJMP(me) == 0)
510 static jmp_buf initial_jmpbuf;
512 /* XXX Make these percpu */
513 static void (*cb_proc)(void *arg);
515 static jmp_buf *cb_back;
517 int start_idle_thread(void *stack, jmp_buf *switch_buf)
521 set_handler(SIGWINCH, (__sighandler_t) sig_handler,
522 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
526 * Can't use UML_SETJMP or UML_LONGJMP here because they save
527 * and restore signals, with the possible side-effect of
528 * trying to handle any signals which came when they were
529 * blocked, which can't be done on this stack.
530 * Signals must be blocked when jumping back here and restored
531 * after returning to the jumper.
533 n = setjmp(initial_jmpbuf);
535 case INIT_JMP_NEW_THREAD:
536 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
537 (*switch_buf)[0].JB_SP = (unsigned long) stack +
538 UM_THREAD_SIZE - sizeof(void *);
540 case INIT_JMP_CALLBACK:
542 longjmp(*cb_back, 1);
547 case INIT_JMP_REBOOT:
551 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
553 longjmp(*switch_buf, 1);
556 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
565 if (UML_SETJMP(&here) == 0)
566 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
577 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
580 void reboot_skas(void)
583 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
586 void __switch_mm(struct mm_id *mm_idp)
590 /* FIXME: need cpu pid in __switch_mm */
592 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
595 panic("__switch_mm - PTRACE_SWITCH_MM failed, "
596 "errno = %d\n", errno);
598 else userspace_pid[0] = mm_idp->u.pid;