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1/*
2 * Architecture-specific signal handling support.
3 *
4 * Copyright (C) 1999-2004 Hewlett-Packard Co
5 * David Mosberger-Tang <davidm@hpl.hp.com>
6 *
7 * Derived from i386 and Alpha versions.
8 */
9
10#include <linux/errno.h>
11#include <linux/kernel.h>
12#include <linux/mm.h>
13#include <linux/ptrace.h>
14#include <linux/tracehook.h>
15#include <linux/sched.h>
16#include <linux/signal.h>
17#include <linux/smp.h>
18#include <linux/stddef.h>
19#include <linux/tty.h>
20#include <linux/binfmts.h>
21#include <linux/unistd.h>
22#include <linux/wait.h>
23
24#include <asm/intrinsics.h>
25#include <asm/uaccess.h>
26#include <asm/rse.h>
27#include <asm/sigcontext.h>
28
29#include "sigframe.h"
30
31#define DEBUG_SIG 0
32#define STACK_ALIGN 16 /* minimal alignment for stack pointer */
33#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
34
35#if _NSIG_WORDS > 1
36# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
37# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
38#else
39# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
40# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
41#endif
42
43asmlinkage long
44sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
45 long arg3, long arg4, long arg5, long arg6, long arg7,
46 struct pt_regs regs)
47{
48 return do_sigaltstack(uss, uoss, regs.r12);
49}
50
51static long
52restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
53{
54 unsigned long ip, flags, nat, um, cfm, rsc;
55 long err;
56
57 /* Always make any pending restarted system calls return -EINTR */
58 current_thread_info()->restart_block.fn = do_no_restart_syscall;
59
60 /* restore scratch that always needs gets updated during signal delivery: */
61 err = __get_user(flags, &sc->sc_flags);
62 err |= __get_user(nat, &sc->sc_nat);
63 err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
64 err |= __get_user(cfm, &sc->sc_cfm);
65 err |= __get_user(um, &sc->sc_um); /* user mask */
66 err |= __get_user(rsc, &sc->sc_ar_rsc);
67 err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
68 err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
69 err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
70 err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
71 err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
72 err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
73 err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
74 err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
75 err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
76 err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
77
78 scr->pt.cr_ifs = cfm | (1UL << 63);
79 scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
80
81 /* establish new instruction pointer: */
82 scr->pt.cr_iip = ip & ~0x3UL;
83 ia64_psr(&scr->pt)->ri = ip & 0x3;
84 scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
85
86 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
87
88 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
89 /* Restore most scratch-state only when not in syscall. */
90 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
91 err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
92 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
93 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
94 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
95 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
96 }
97
98 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
99 struct ia64_psr *psr = ia64_psr(&scr->pt);
100
101 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
102 psr->mfh = 0; /* drop signal handler's fph contents... */
103 preempt_disable();
104 if (psr->dfh)
105 ia64_drop_fpu(current);
106 else {
107 /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
108 __ia64_load_fpu(current->thread.fph);
109 ia64_set_local_fpu_owner(current);
110 }
111 preempt_enable();
112 }
113 return err;
114}
115
116int
117copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
118{
119 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
120 return -EFAULT;
121 if (from->si_code < 0) {
122 if (__copy_to_user(to, from, sizeof(siginfo_t)))
123 return -EFAULT;
124 return 0;
125 } else {
126 int err;
127
128 /*
129 * If you change siginfo_t structure, please be sure this code is fixed
130 * accordingly. It should never copy any pad contained in the structure
131 * to avoid security leaks, but must copy the generic 3 ints plus the
132 * relevant union member.
133 */
134 err = __put_user(from->si_signo, &to->si_signo);
135 err |= __put_user(from->si_errno, &to->si_errno);
136 err |= __put_user((short)from->si_code, &to->si_code);
137 switch (from->si_code >> 16) {
138 case __SI_FAULT >> 16:
139 err |= __put_user(from->si_flags, &to->si_flags);
140 err |= __put_user(from->si_isr, &to->si_isr);
141 case __SI_POLL >> 16:
142 err |= __put_user(from->si_addr, &to->si_addr);
143 err |= __put_user(from->si_imm, &to->si_imm);
144 break;
145 case __SI_TIMER >> 16:
146 err |= __put_user(from->si_tid, &to->si_tid);
147 err |= __put_user(from->si_overrun, &to->si_overrun);
148 err |= __put_user(from->si_ptr, &to->si_ptr);
149 break;
150 case __SI_RT >> 16: /* Not generated by the kernel as of now. */
151 case __SI_MESGQ >> 16:
152 err |= __put_user(from->si_uid, &to->si_uid);
153 err |= __put_user(from->si_pid, &to->si_pid);
154 err |= __put_user(from->si_ptr, &to->si_ptr);
155 break;
156 case __SI_CHLD >> 16:
157 err |= __put_user(from->si_utime, &to->si_utime);
158 err |= __put_user(from->si_stime, &to->si_stime);
159 err |= __put_user(from->si_status, &to->si_status);
160 default:
161 err |= __put_user(from->si_uid, &to->si_uid);
162 err |= __put_user(from->si_pid, &to->si_pid);
163 break;
164 }
165 return err;
166 }
167}
168
169long
170ia64_rt_sigreturn (struct sigscratch *scr)
171{
172 extern char ia64_strace_leave_kernel, ia64_leave_kernel;
173 struct sigcontext __user *sc;
174 struct siginfo si;
175 sigset_t set;
176 long retval;
177
178 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
179
180 /*
181 * When we return to the previously executing context, r8 and r10 have already
182 * been setup the way we want them. Indeed, if the signal wasn't delivered while
183 * in a system call, we must not touch r8 or r10 as otherwise user-level state
184 * could be corrupted.
185 */
186 retval = (long) &ia64_leave_kernel;
187 if (test_thread_flag(TIF_SYSCALL_TRACE)
188 || test_thread_flag(TIF_SYSCALL_AUDIT))
189 /*
190 * strace expects to be notified after sigreturn returns even though the
191 * context to which we return may not be in the middle of a syscall.
192 * Thus, the return-value that strace displays for sigreturn is
193 * meaningless.
194 */
195 retval = (long) &ia64_strace_leave_kernel;
196
197 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
198 goto give_sigsegv;
199
200 if (GET_SIGSET(&set, &sc->sc_mask))
201 goto give_sigsegv;
202
203 sigdelsetmask(&set, ~_BLOCKABLE);
204
205 spin_lock_irq(¤t->sighand->siglock);
206 {
207 current->blocked = set;
208 recalc_sigpending();
209 }
210 spin_unlock_irq(¤t->sighand->siglock);
211
212 if (restore_sigcontext(sc, scr))
213 goto give_sigsegv;
214
215#if DEBUG_SIG
216 printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
217 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
218#endif
219 /*
220 * It is more difficult to avoid calling this function than to
221 * call it and ignore errors.
222 */
223 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
224 return retval;
225
226 give_sigsegv:
227 si.si_signo = SIGSEGV;
228 si.si_errno = 0;
229 si.si_code = SI_KERNEL;
230 si.si_pid = task_pid_vnr(current);
231 si.si_uid = current_uid();
232 si.si_addr = sc;
233 force_sig_info(SIGSEGV, &si, current);
234 return retval;
235}
236
237/*
238 * This does just the minimum required setup of sigcontext.
239 * Specifically, it only installs data that is either not knowable at
240 * the user-level or that gets modified before execution in the
241 * trampoline starts. Everything else is done at the user-level.
242 */
243static long
244setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
245{
246 unsigned long flags = 0, ifs, cfm, nat;
247 long err = 0;
248
249 ifs = scr->pt.cr_ifs;
250
251 if (on_sig_stack((unsigned long) sc))
252 flags |= IA64_SC_FLAG_ONSTACK;
253 if ((ifs & (1UL << 63)) == 0)
254 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
255 flags |= IA64_SC_FLAG_IN_SYSCALL;
256 cfm = ifs & ((1UL << 38) - 1);
257 ia64_flush_fph(current);
258 if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
259 flags |= IA64_SC_FLAG_FPH_VALID;
260 err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
261 }
262
263 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
264
265 err |= __put_user(flags, &sc->sc_flags);
266 err |= __put_user(nat, &sc->sc_nat);
267 err |= PUT_SIGSET(mask, &sc->sc_mask);
268 err |= __put_user(cfm, &sc->sc_cfm);
269 err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
270 err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
271 err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
272 err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
273 err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
274 err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
275 err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
276 err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
277 err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
278 err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
279 err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
280 err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
281 err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
282
283 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
284 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
285 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
286 err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
287 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
288 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
289 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
290 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
291 }
292 return err;
293}
294
295/*
296 * Check whether the register-backing store is already on the signal stack.
297 */
298static inline int
299rbs_on_sig_stack (unsigned long bsp)
300{
301 return (bsp - current->sas_ss_sp < current->sas_ss_size);
302}
303
304static long
305force_sigsegv_info (int sig, void __user *addr)
306{
307 unsigned long flags;
308 struct siginfo si;
309
310 if (sig == SIGSEGV) {
311 /*
312 * Acquiring siglock around the sa_handler-update is almost
313 * certainly overkill, but this isn't a
314 * performance-critical path and I'd rather play it safe
315 * here than having to debug a nasty race if and when
316 * something changes in kernel/signal.c that would make it
317 * no longer safe to modify sa_handler without holding the
318 * lock.
319 */
320 spin_lock_irqsave(¤t->sighand->siglock, flags);
321 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
322 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
323 }
324 si.si_signo = SIGSEGV;
325 si.si_errno = 0;
326 si.si_code = SI_KERNEL;
327 si.si_pid = task_pid_vnr(current);
328 si.si_uid = current_uid();
329 si.si_addr = addr;
330 force_sig_info(SIGSEGV, &si, current);
331 return 0;
332}
333
334static long
335setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
336 struct sigscratch *scr)
337{
338 extern char __kernel_sigtramp[];
339 unsigned long tramp_addr, new_rbs = 0, new_sp;
340 struct sigframe __user *frame;
341 long err;
342
343 new_sp = scr->pt.r12;
344 tramp_addr = (unsigned long) __kernel_sigtramp;
345 if (ka->sa.sa_flags & SA_ONSTACK) {
346 int onstack = sas_ss_flags(new_sp);
347
348 if (onstack == 0) {
349 new_sp = current->sas_ss_sp + current->sas_ss_size;
350 /*
351 * We need to check for the register stack being on the
352 * signal stack separately, because it's switched
353 * separately (memory stack is switched in the kernel,
354 * register stack is switched in the signal trampoline).
355 */
356 if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
357 new_rbs = ALIGN(current->sas_ss_sp,
358 sizeof(long));
359 } else if (onstack == SS_ONSTACK) {
360 unsigned long check_sp;
361
362 /*
363 * If we are on the alternate signal stack and would
364 * overflow it, don't. Return an always-bogus address
365 * instead so we will die with SIGSEGV.
366 */
367 check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
368 if (!likely(on_sig_stack(check_sp)))
369 return force_sigsegv_info(sig, (void __user *)
370 check_sp);
371 }
372 }
373 frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
374
375 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
376 return force_sigsegv_info(sig, frame);
377
378 err = __put_user(sig, &frame->arg0);
379 err |= __put_user(&frame->info, &frame->arg1);
380 err |= __put_user(&frame->sc, &frame->arg2);
381 err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
382 err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
383 err |= __put_user(ka->sa.sa_handler, &frame->handler);
384
385 err |= copy_siginfo_to_user(&frame->info, info);
386
387 err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
388 err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
389 err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
390 err |= setup_sigcontext(&frame->sc, set, scr);
391
392 if (unlikely(err))
393 return force_sigsegv_info(sig, frame);
394
395 scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
396 scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
397 scr->pt.cr_iip = tramp_addr;
398 ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
399 ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */
400 /*
401 * Force the interruption function mask to zero. This has no effect when a
402 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
403 * ignored), but it has the desirable effect of making it possible to deliver a
404 * signal with an incomplete register frame (which happens when a mandatory RSE
405 * load faults). Furthermore, it has no negative effect on the getting the user's
406 * dirty partition preserved, because that's governed by scr->pt.loadrs.
407 */
408 scr->pt.cr_ifs = (1UL << 63);
409
410 /*
411 * Note: this affects only the NaT bits of the scratch regs (the ones saved in
412 * pt_regs), which is exactly what we want.
413 */
414 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
415
416#if DEBUG_SIG
417 printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
418 current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
419#endif
420 return 1;
421}
422
423static long
424handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
425 struct sigscratch *scr)
426{
427 if (!setup_frame(sig, ka, info, oldset, scr))
428 return 0;
429
430 spin_lock_irq(¤t->sighand->siglock);
431 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
432 if (!(ka->sa.sa_flags & SA_NODEFER))
433 sigaddset(¤t->blocked, sig);
434 recalc_sigpending();
435 spin_unlock_irq(¤t->sighand->siglock);
436
437 /*
438 * Let tracing know that we've done the handler setup.
439 */
440 tracehook_signal_handler(sig, info, ka, &scr->pt,
441 test_thread_flag(TIF_SINGLESTEP));
442
443 return 1;
444}
445
446/*
447 * Note that `init' is a special process: it doesn't get signals it doesn't want to
448 * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
449 */
450void
451ia64_do_signal (struct sigscratch *scr, long in_syscall)
452{
453 struct k_sigaction ka;
454 sigset_t *oldset;
455 siginfo_t info;
456 long restart = in_syscall;
457 long errno = scr->pt.r8;
458
459 /*
460 * In the ia64_leave_kernel code path, we want the common case to go fast, which
461 * is why we may in certain cases get here from kernel mode. Just return without
462 * doing anything if so.
463 */
464 if (!user_mode(&scr->pt))
465 return;
466
467 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
468 oldset = ¤t->saved_sigmask;
469 else
470 oldset = ¤t->blocked;
471
472 /*
473 * This only loops in the rare cases of handle_signal() failing, in which case we
474 * need to push through a forced SIGSEGV.
475 */
476 while (1) {
477 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
478
479 /*
480 * get_signal_to_deliver() may have run a debugger (via notify_parent())
481 * and the debugger may have modified the state (e.g., to arrange for an
482 * inferior call), thus it's important to check for restarting _after_
483 * get_signal_to_deliver().
484 */
485 if ((long) scr->pt.r10 != -1)
486 /*
487 * A system calls has to be restarted only if one of the error codes
488 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
489 * isn't -1 then r8 doesn't hold an error code and we don't need to
490 * restart the syscall, so we can clear the "restart" flag here.
491 */
492 restart = 0;
493
494 if (signr <= 0)
495 break;
496
497 if (unlikely(restart)) {
498 switch (errno) {
499 case ERESTART_RESTARTBLOCK:
500 case ERESTARTNOHAND:
501 scr->pt.r8 = EINTR;
502 /* note: scr->pt.r10 is already -1 */
503 break;
504
505 case ERESTARTSYS:
506 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
507 scr->pt.r8 = EINTR;
508 /* note: scr->pt.r10 is already -1 */
509 break;
510 }
511 case ERESTARTNOINTR:
512 ia64_decrement_ip(&scr->pt);
513 restart = 0; /* don't restart twice if handle_signal() fails... */
514 }
515 }
516
517 /*
518 * Whee! Actually deliver the signal. If the delivery failed, we need to
519 * continue to iterate in this loop so we can deliver the SIGSEGV...
520 */
521 if (handle_signal(signr, &ka, &info, oldset, scr)) {
522 /*
523 * A signal was successfully delivered; the saved
524 * sigmask will have been stored in the signal frame,
525 * and will be restored by sigreturn, so we can simply
526 * clear the TS_RESTORE_SIGMASK flag.
527 */
528 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
529 return;
530 }
531 }
532
533 /* Did we come from a system call? */
534 if (restart) {
535 /* Restart the system call - no handlers present */
536 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
537 || errno == ERESTART_RESTARTBLOCK)
538 {
539 /*
540 * Note: the syscall number is in r15 which is saved in
541 * pt_regs so all we need to do here is adjust ip so that
542 * the "break" instruction gets re-executed.
543 */
544 ia64_decrement_ip(&scr->pt);
545 if (errno == ERESTART_RESTARTBLOCK)
546 scr->pt.r15 = __NR_restart_syscall;
547 }
548 }
549
550 /* if there's no signal to deliver, we just put the saved sigmask
551 * back */
552 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
553 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
554 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
555 }
556}
1/*
2 * Architecture-specific signal handling support.
3 *
4 * Copyright (C) 1999-2004 Hewlett-Packard Co
5 * David Mosberger-Tang <davidm@hpl.hp.com>
6 *
7 * Derived from i386 and Alpha versions.
8 */
9
10#include <linux/errno.h>
11#include <linux/kernel.h>
12#include <linux/mm.h>
13#include <linux/ptrace.h>
14#include <linux/tracehook.h>
15#include <linux/sched.h>
16#include <linux/signal.h>
17#include <linux/smp.h>
18#include <linux/stddef.h>
19#include <linux/tty.h>
20#include <linux/binfmts.h>
21#include <linux/unistd.h>
22#include <linux/wait.h>
23
24#include <asm/intrinsics.h>
25#include <asm/uaccess.h>
26#include <asm/rse.h>
27#include <asm/sigcontext.h>
28
29#include "sigframe.h"
30
31#define DEBUG_SIG 0
32#define STACK_ALIGN 16 /* minimal alignment for stack pointer */
33
34#if _NSIG_WORDS > 1
35# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
36# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
37#else
38# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
39# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
40#endif
41
42asmlinkage long
43sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
44 long arg3, long arg4, long arg5, long arg6, long arg7,
45 struct pt_regs regs)
46{
47 return do_sigaltstack(uss, uoss, regs.r12);
48}
49
50static long
51restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
52{
53 unsigned long ip, flags, nat, um, cfm, rsc;
54 long err;
55
56 /* Always make any pending restarted system calls return -EINTR */
57 current_thread_info()->restart_block.fn = do_no_restart_syscall;
58
59 /* restore scratch that always needs gets updated during signal delivery: */
60 err = __get_user(flags, &sc->sc_flags);
61 err |= __get_user(nat, &sc->sc_nat);
62 err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
63 err |= __get_user(cfm, &sc->sc_cfm);
64 err |= __get_user(um, &sc->sc_um); /* user mask */
65 err |= __get_user(rsc, &sc->sc_ar_rsc);
66 err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
67 err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
68 err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
69 err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
70 err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
71 err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
72 err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
73 err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
74 err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
75 err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
76
77 scr->pt.cr_ifs = cfm | (1UL << 63);
78 scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
79
80 /* establish new instruction pointer: */
81 scr->pt.cr_iip = ip & ~0x3UL;
82 ia64_psr(&scr->pt)->ri = ip & 0x3;
83 scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
84
85 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
86
87 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
88 /* Restore most scratch-state only when not in syscall. */
89 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
90 err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
91 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
92 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
93 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
94 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
95 }
96
97 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
98 struct ia64_psr *psr = ia64_psr(&scr->pt);
99
100 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
101 psr->mfh = 0; /* drop signal handler's fph contents... */
102 preempt_disable();
103 if (psr->dfh)
104 ia64_drop_fpu(current);
105 else {
106 /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
107 __ia64_load_fpu(current->thread.fph);
108 ia64_set_local_fpu_owner(current);
109 }
110 preempt_enable();
111 }
112 return err;
113}
114
115int
116copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
117{
118 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
119 return -EFAULT;
120 if (from->si_code < 0) {
121 if (__copy_to_user(to, from, sizeof(siginfo_t)))
122 return -EFAULT;
123 return 0;
124 } else {
125 int err;
126
127 /*
128 * If you change siginfo_t structure, please be sure this code is fixed
129 * accordingly. It should never copy any pad contained in the structure
130 * to avoid security leaks, but must copy the generic 3 ints plus the
131 * relevant union member.
132 */
133 err = __put_user(from->si_signo, &to->si_signo);
134 err |= __put_user(from->si_errno, &to->si_errno);
135 err |= __put_user((short)from->si_code, &to->si_code);
136 switch (from->si_code >> 16) {
137 case __SI_FAULT >> 16:
138 err |= __put_user(from->si_flags, &to->si_flags);
139 err |= __put_user(from->si_isr, &to->si_isr);
140 case __SI_POLL >> 16:
141 err |= __put_user(from->si_addr, &to->si_addr);
142 err |= __put_user(from->si_imm, &to->si_imm);
143 break;
144 case __SI_TIMER >> 16:
145 err |= __put_user(from->si_tid, &to->si_tid);
146 err |= __put_user(from->si_overrun, &to->si_overrun);
147 err |= __put_user(from->si_ptr, &to->si_ptr);
148 break;
149 case __SI_RT >> 16: /* Not generated by the kernel as of now. */
150 case __SI_MESGQ >> 16:
151 err |= __put_user(from->si_uid, &to->si_uid);
152 err |= __put_user(from->si_pid, &to->si_pid);
153 err |= __put_user(from->si_ptr, &to->si_ptr);
154 break;
155 case __SI_CHLD >> 16:
156 err |= __put_user(from->si_utime, &to->si_utime);
157 err |= __put_user(from->si_stime, &to->si_stime);
158 err |= __put_user(from->si_status, &to->si_status);
159 default:
160 err |= __put_user(from->si_uid, &to->si_uid);
161 err |= __put_user(from->si_pid, &to->si_pid);
162 break;
163 }
164 return err;
165 }
166}
167
168long
169ia64_rt_sigreturn (struct sigscratch *scr)
170{
171 extern char ia64_strace_leave_kernel, ia64_leave_kernel;
172 struct sigcontext __user *sc;
173 struct siginfo si;
174 sigset_t set;
175 long retval;
176
177 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
178
179 /*
180 * When we return to the previously executing context, r8 and r10 have already
181 * been setup the way we want them. Indeed, if the signal wasn't delivered while
182 * in a system call, we must not touch r8 or r10 as otherwise user-level state
183 * could be corrupted.
184 */
185 retval = (long) &ia64_leave_kernel;
186 if (test_thread_flag(TIF_SYSCALL_TRACE)
187 || test_thread_flag(TIF_SYSCALL_AUDIT))
188 /*
189 * strace expects to be notified after sigreturn returns even though the
190 * context to which we return may not be in the middle of a syscall.
191 * Thus, the return-value that strace displays for sigreturn is
192 * meaningless.
193 */
194 retval = (long) &ia64_strace_leave_kernel;
195
196 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
197 goto give_sigsegv;
198
199 if (GET_SIGSET(&set, &sc->sc_mask))
200 goto give_sigsegv;
201
202 set_current_blocked(&set);
203
204 if (restore_sigcontext(sc, scr))
205 goto give_sigsegv;
206
207#if DEBUG_SIG
208 printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
209 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
210#endif
211 /*
212 * It is more difficult to avoid calling this function than to
213 * call it and ignore errors.
214 */
215 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
216 return retval;
217
218 give_sigsegv:
219 si.si_signo = SIGSEGV;
220 si.si_errno = 0;
221 si.si_code = SI_KERNEL;
222 si.si_pid = task_pid_vnr(current);
223 si.si_uid = current_uid();
224 si.si_addr = sc;
225 force_sig_info(SIGSEGV, &si, current);
226 return retval;
227}
228
229/*
230 * This does just the minimum required setup of sigcontext.
231 * Specifically, it only installs data that is either not knowable at
232 * the user-level or that gets modified before execution in the
233 * trampoline starts. Everything else is done at the user-level.
234 */
235static long
236setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
237{
238 unsigned long flags = 0, ifs, cfm, nat;
239 long err = 0;
240
241 ifs = scr->pt.cr_ifs;
242
243 if (on_sig_stack((unsigned long) sc))
244 flags |= IA64_SC_FLAG_ONSTACK;
245 if ((ifs & (1UL << 63)) == 0)
246 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
247 flags |= IA64_SC_FLAG_IN_SYSCALL;
248 cfm = ifs & ((1UL << 38) - 1);
249 ia64_flush_fph(current);
250 if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
251 flags |= IA64_SC_FLAG_FPH_VALID;
252 err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
253 }
254
255 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
256
257 err |= __put_user(flags, &sc->sc_flags);
258 err |= __put_user(nat, &sc->sc_nat);
259 err |= PUT_SIGSET(mask, &sc->sc_mask);
260 err |= __put_user(cfm, &sc->sc_cfm);
261 err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
262 err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
263 err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
264 err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
265 err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
266 err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
267 err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
268 err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
269 err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
270 err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
271 err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
272 err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
273 err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
274
275 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
276 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
277 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
278 err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
279 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
280 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
281 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
282 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
283 }
284 return err;
285}
286
287/*
288 * Check whether the register-backing store is already on the signal stack.
289 */
290static inline int
291rbs_on_sig_stack (unsigned long bsp)
292{
293 return (bsp - current->sas_ss_sp < current->sas_ss_size);
294}
295
296static long
297force_sigsegv_info (int sig, void __user *addr)
298{
299 unsigned long flags;
300 struct siginfo si;
301
302 if (sig == SIGSEGV) {
303 /*
304 * Acquiring siglock around the sa_handler-update is almost
305 * certainly overkill, but this isn't a
306 * performance-critical path and I'd rather play it safe
307 * here than having to debug a nasty race if and when
308 * something changes in kernel/signal.c that would make it
309 * no longer safe to modify sa_handler without holding the
310 * lock.
311 */
312 spin_lock_irqsave(¤t->sighand->siglock, flags);
313 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
314 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
315 }
316 si.si_signo = SIGSEGV;
317 si.si_errno = 0;
318 si.si_code = SI_KERNEL;
319 si.si_pid = task_pid_vnr(current);
320 si.si_uid = current_uid();
321 si.si_addr = addr;
322 force_sig_info(SIGSEGV, &si, current);
323 return 0;
324}
325
326static long
327setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
328 struct sigscratch *scr)
329{
330 extern char __kernel_sigtramp[];
331 unsigned long tramp_addr, new_rbs = 0, new_sp;
332 struct sigframe __user *frame;
333 long err;
334
335 new_sp = scr->pt.r12;
336 tramp_addr = (unsigned long) __kernel_sigtramp;
337 if (ka->sa.sa_flags & SA_ONSTACK) {
338 int onstack = sas_ss_flags(new_sp);
339
340 if (onstack == 0) {
341 new_sp = current->sas_ss_sp + current->sas_ss_size;
342 /*
343 * We need to check for the register stack being on the
344 * signal stack separately, because it's switched
345 * separately (memory stack is switched in the kernel,
346 * register stack is switched in the signal trampoline).
347 */
348 if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
349 new_rbs = ALIGN(current->sas_ss_sp,
350 sizeof(long));
351 } else if (onstack == SS_ONSTACK) {
352 unsigned long check_sp;
353
354 /*
355 * If we are on the alternate signal stack and would
356 * overflow it, don't. Return an always-bogus address
357 * instead so we will die with SIGSEGV.
358 */
359 check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
360 if (!likely(on_sig_stack(check_sp)))
361 return force_sigsegv_info(sig, (void __user *)
362 check_sp);
363 }
364 }
365 frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
366
367 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
368 return force_sigsegv_info(sig, frame);
369
370 err = __put_user(sig, &frame->arg0);
371 err |= __put_user(&frame->info, &frame->arg1);
372 err |= __put_user(&frame->sc, &frame->arg2);
373 err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
374 err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
375 err |= __put_user(ka->sa.sa_handler, &frame->handler);
376
377 err |= copy_siginfo_to_user(&frame->info, info);
378
379 err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
380 err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
381 err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
382 err |= setup_sigcontext(&frame->sc, set, scr);
383
384 if (unlikely(err))
385 return force_sigsegv_info(sig, frame);
386
387 scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
388 scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
389 scr->pt.cr_iip = tramp_addr;
390 ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
391 ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */
392 /*
393 * Force the interruption function mask to zero. This has no effect when a
394 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
395 * ignored), but it has the desirable effect of making it possible to deliver a
396 * signal with an incomplete register frame (which happens when a mandatory RSE
397 * load faults). Furthermore, it has no negative effect on the getting the user's
398 * dirty partition preserved, because that's governed by scr->pt.loadrs.
399 */
400 scr->pt.cr_ifs = (1UL << 63);
401
402 /*
403 * Note: this affects only the NaT bits of the scratch regs (the ones saved in
404 * pt_regs), which is exactly what we want.
405 */
406 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
407
408#if DEBUG_SIG
409 printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
410 current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
411#endif
412 return 1;
413}
414
415static long
416handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
417 struct sigscratch *scr)
418{
419 if (!setup_frame(sig, ka, info, sigmask_to_save(), scr))
420 return 0;
421
422 signal_delivered(sig, info, ka, &scr->pt,
423 test_thread_flag(TIF_SINGLESTEP));
424
425 return 1;
426}
427
428/*
429 * Note that `init' is a special process: it doesn't get signals it doesn't want to
430 * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
431 */
432void
433ia64_do_signal (struct sigscratch *scr, long in_syscall)
434{
435 struct k_sigaction ka;
436 siginfo_t info;
437 long restart = in_syscall;
438 long errno = scr->pt.r8;
439
440 /*
441 * In the ia64_leave_kernel code path, we want the common case to go fast, which
442 * is why we may in certain cases get here from kernel mode. Just return without
443 * doing anything if so.
444 */
445 if (!user_mode(&scr->pt))
446 return;
447
448 /*
449 * This only loops in the rare cases of handle_signal() failing, in which case we
450 * need to push through a forced SIGSEGV.
451 */
452 while (1) {
453 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
454
455 /*
456 * get_signal_to_deliver() may have run a debugger (via notify_parent())
457 * and the debugger may have modified the state (e.g., to arrange for an
458 * inferior call), thus it's important to check for restarting _after_
459 * get_signal_to_deliver().
460 */
461 if ((long) scr->pt.r10 != -1)
462 /*
463 * A system calls has to be restarted only if one of the error codes
464 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
465 * isn't -1 then r8 doesn't hold an error code and we don't need to
466 * restart the syscall, so we can clear the "restart" flag here.
467 */
468 restart = 0;
469
470 if (signr <= 0)
471 break;
472
473 if (unlikely(restart)) {
474 switch (errno) {
475 case ERESTART_RESTARTBLOCK:
476 case ERESTARTNOHAND:
477 scr->pt.r8 = EINTR;
478 /* note: scr->pt.r10 is already -1 */
479 break;
480
481 case ERESTARTSYS:
482 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
483 scr->pt.r8 = EINTR;
484 /* note: scr->pt.r10 is already -1 */
485 break;
486 }
487 case ERESTARTNOINTR:
488 ia64_decrement_ip(&scr->pt);
489 restart = 0; /* don't restart twice if handle_signal() fails... */
490 }
491 }
492
493 /*
494 * Whee! Actually deliver the signal. If the delivery failed, we need to
495 * continue to iterate in this loop so we can deliver the SIGSEGV...
496 */
497 if (handle_signal(signr, &ka, &info, scr))
498 return;
499 }
500
501 /* Did we come from a system call? */
502 if (restart) {
503 /* Restart the system call - no handlers present */
504 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
505 || errno == ERESTART_RESTARTBLOCK)
506 {
507 /*
508 * Note: the syscall number is in r15 which is saved in
509 * pt_regs so all we need to do here is adjust ip so that
510 * the "break" instruction gets re-executed.
511 */
512 ia64_decrement_ip(&scr->pt);
513 if (errno == ERESTART_RESTARTBLOCK)
514 scr->pt.r15 = __NR_restart_syscall;
515 }
516 }
517
518 /* if there's no signal to deliver, we just put the saved sigmask
519 * back */
520 restore_saved_sigmask();
521}