2 * Architecture-specific signal handling support.
4 * Copyright (C) 1999-2004 Hewlett-Packard Co
5 * David Mosberger-Tang <davidm@hpl.hp.com>
7 * Derived from i386 and Alpha versions.
10 #include <linux/errno.h>
11 #include <linux/kernel.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>
24 #include <asm/intrinsics.h>
25 #include <asm/uaccess.h>
27 #include <asm/sigcontext.h>
32 #define STACK_ALIGN 16 /* minimal alignment for stack pointer */
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))
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])
43 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
44 long arg3, long arg4, long arg5, long arg6, long arg7,
47 return do_sigaltstack(uss, uoss, regs.r12);
51 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
53 unsigned long ip, flags, nat, um, cfm, rsc;
56 /* Always make any pending restarted system calls return -EINTR */
57 current_thread_info()->restart_block.fn = do_no_restart_syscall;
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 */
77 scr->pt.cr_ifs = cfm | (1UL << 63);
78 scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
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);
85 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
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 */
97 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
98 struct ia64_psr *psr = ia64_psr(&scr->pt);
100 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
101 psr->mfh = 0; /* drop signal handler's fph contents... */
104 ia64_drop_fpu(current);
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);
116 copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
118 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
120 if (from->si_code < 0) {
121 if (__copy_to_user(to, from, sizeof(siginfo_t)))
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.
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);
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);
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);
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);
160 err |= __put_user(from->si_uid, &to->si_uid);
161 err |= __put_user(from->si_pid, &to->si_pid);
169 ia64_rt_sigreturn (struct sigscratch *scr)
171 extern char ia64_strace_leave_kernel, ia64_leave_kernel;
172 struct sigcontext __user *sc;
177 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
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.
185 retval = (long) &ia64_leave_kernel;
186 if (test_thread_flag(TIF_SYSCALL_TRACE)
187 || test_thread_flag(TIF_SYSCALL_AUDIT))
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
194 retval = (long) &ia64_strace_leave_kernel;
196 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
199 if (GET_SIGSET(&set, &sc->sc_mask))
202 set_current_blocked(&set);
204 if (restore_sigcontext(sc, scr))
208 printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
209 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
212 * It is more difficult to avoid calling this function than to
213 * call it and ignore errors.
215 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
219 si.si_signo = SIGSEGV;
221 si.si_code = SI_KERNEL;
222 si.si_pid = task_pid_vnr(current);
223 si.si_uid = current_uid();
225 force_sig_info(SIGSEGV, &si, current);
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.
236 setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
238 unsigned long flags = 0, ifs, cfm, nat;
241 ifs = scr->pt.cr_ifs;
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);
255 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
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);
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 */
288 * Check whether the register-backing store is already on the signal stack.
291 rbs_on_sig_stack (unsigned long bsp)
293 return (bsp - current->sas_ss_sp < current->sas_ss_size);
297 force_sigsegv_info (int sig, void __user *addr)
302 if (sig == SIGSEGV) {
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
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);
316 si.si_signo = SIGSEGV;
318 si.si_code = SI_KERNEL;
319 si.si_pid = task_pid_vnr(current);
320 si.si_uid = current_uid();
322 force_sig_info(SIGSEGV, &si, current);
327 setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
328 struct sigscratch *scr)
330 extern char __kernel_sigtramp[];
331 unsigned long tramp_addr, new_rbs = 0, new_sp;
332 struct sigframe __user *frame;
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);
341 new_sp = current->sas_ss_sp + current->sas_ss_size;
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).
348 if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
349 new_rbs = ALIGN(current->sas_ss_sp,
351 } else if (onstack == SS_ONSTACK) {
352 unsigned long check_sp;
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.
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 *)
365 frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
367 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
368 return force_sigsegv_info(sig, frame);
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);
377 err |= copy_siginfo_to_user(&frame->info, info);
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);
385 return force_sigsegv_info(sig, frame);
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 */
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.
400 scr->pt.cr_ifs = (1UL << 63);
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.
406 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
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);
416 handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
417 struct sigscratch *scr)
419 if (!setup_frame(sig, ka, info, sigmask_to_save(), scr))
422 block_sigmask(ka, sig);
425 * Let tracing know that we've done the handler setup.
427 tracehook_signal_handler(sig, info, ka, &scr->pt,
428 test_thread_flag(TIF_SINGLESTEP));
434 * Note that `init' is a special process: it doesn't get signals it doesn't want to
435 * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
438 ia64_do_signal (struct sigscratch *scr, long in_syscall)
440 struct k_sigaction ka;
442 long restart = in_syscall;
443 long errno = scr->pt.r8;
446 * In the ia64_leave_kernel code path, we want the common case to go fast, which
447 * is why we may in certain cases get here from kernel mode. Just return without
448 * doing anything if so.
450 if (!user_mode(&scr->pt))
454 * This only loops in the rare cases of handle_signal() failing, in which case we
455 * need to push through a forced SIGSEGV.
458 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
461 * get_signal_to_deliver() may have run a debugger (via notify_parent())
462 * and the debugger may have modified the state (e.g., to arrange for an
463 * inferior call), thus it's important to check for restarting _after_
464 * get_signal_to_deliver().
466 if ((long) scr->pt.r10 != -1)
468 * A system calls has to be restarted only if one of the error codes
469 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
470 * isn't -1 then r8 doesn't hold an error code and we don't need to
471 * restart the syscall, so we can clear the "restart" flag here.
478 if (unlikely(restart)) {
480 case ERESTART_RESTARTBLOCK:
483 /* note: scr->pt.r10 is already -1 */
487 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
489 /* note: scr->pt.r10 is already -1 */
493 ia64_decrement_ip(&scr->pt);
494 restart = 0; /* don't restart twice if handle_signal() fails... */
499 * Whee! Actually deliver the signal. If the delivery failed, we need to
500 * continue to iterate in this loop so we can deliver the SIGSEGV...
502 if (handle_signal(signr, &ka, &info, scr))
506 /* Did we come from a system call? */
508 /* Restart the system call - no handlers present */
509 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
510 || errno == ERESTART_RESTARTBLOCK)
513 * Note: the syscall number is in r15 which is saved in
514 * pt_regs so all we need to do here is adjust ip so that
515 * the "break" instruction gets re-executed.
517 ia64_decrement_ip(&scr->pt);
518 if (errno == ERESTART_RESTARTBLOCK)
519 scr->pt.r15 = __NR_restart_syscall;
523 /* if there's no signal to deliver, we just put the saved sigmask
525 restore_saved_sigmask();