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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ia64/kernel/signal.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/ia64/kernel/signal.c')
-rw-r--r--arch/ia64/kernel/signal.c691
1 files changed, 691 insertions, 0 deletions
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
new file mode 100644
index 000000000000..6891d86937d9
--- /dev/null
+++ b/arch/ia64/kernel/signal.c
@@ -0,0 +1,691 @@
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/config.h>
11#include <linux/errno.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/ptrace.h>
15#include <linux/sched.h>
16#include <linux/signal.h>
17#include <linux/smp.h>
18#include <linux/smp_lock.h>
19#include <linux/stddef.h>
20#include <linux/tty.h>
21#include <linux/binfmts.h>
22#include <linux/unistd.h>
23#include <linux/wait.h>
24
25#include <asm/ia32.h>
26#include <asm/intrinsics.h>
27#include <asm/uaccess.h>
28#include <asm/rse.h>
29#include <asm/sigcontext.h>
30
31#include "sigframe.h"
32
33#define DEBUG_SIG 0
34#define STACK_ALIGN 16 /* minimal alignment for stack pointer */
35#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
36
37#if _NSIG_WORDS > 1
38# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
39# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
40#else
41# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
42# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
43#endif
44
45long
46ia64_rt_sigsuspend (sigset_t __user *uset, size_t sigsetsize, struct sigscratch *scr)
47{
48 sigset_t oldset, set;
49
50 /* XXX: Don't preclude handling different sized sigset_t's. */
51 if (sigsetsize != sizeof(sigset_t))
52 return -EINVAL;
53
54 if (!access_ok(VERIFY_READ, uset, sigsetsize))
55 return -EFAULT;
56
57 if (GET_SIGSET(&set, uset))
58 return -EFAULT;
59
60 sigdelsetmask(&set, ~_BLOCKABLE);
61
62 spin_lock_irq(&current->sighand->siglock);
63 {
64 oldset = current->blocked;
65 current->blocked = set;
66 recalc_sigpending();
67 }
68 spin_unlock_irq(&current->sighand->siglock);
69
70 /*
71 * The return below usually returns to the signal handler. We need to
72 * pre-set the correct error code here to ensure that the right values
73 * get saved in sigcontext by ia64_do_signal.
74 */
75 scr->pt.r8 = EINTR;
76 scr->pt.r10 = -1;
77
78 while (1) {
79 current->state = TASK_INTERRUPTIBLE;
80 schedule();
81 if (ia64_do_signal(&oldset, scr, 1))
82 return -EINTR;
83 }
84}
85
86asmlinkage long
87sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
88 long arg3, long arg4, long arg5, long arg6, long arg7,
89 struct pt_regs regs)
90{
91 return do_sigaltstack(uss, uoss, regs.r12);
92}
93
94static long
95restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
96{
97 unsigned long ip, flags, nat, um, cfm;
98 long err;
99
100 /* Always make any pending restarted system calls return -EINTR */
101 current_thread_info()->restart_block.fn = do_no_restart_syscall;
102
103 /* restore scratch that always needs gets updated during signal delivery: */
104 err = __get_user(flags, &sc->sc_flags);
105 err |= __get_user(nat, &sc->sc_nat);
106 err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
107 err |= __get_user(cfm, &sc->sc_cfm);
108 err |= __get_user(um, &sc->sc_um); /* user mask */
109 err |= __get_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
110 err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
111 err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
112 err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
113 err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
114 err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
115 err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
116 err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
117 err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
118 err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
119 err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
120
121 scr->pt.cr_ifs = cfm | (1UL << 63);
122
123 /* establish new instruction pointer: */
124 scr->pt.cr_iip = ip & ~0x3UL;
125 ia64_psr(&scr->pt)->ri = ip & 0x3;
126 scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
127
128 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
129
130 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
131 /* Restore most scratch-state only when not in syscall. */
132 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
133 err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
134 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
135 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
136 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
137 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
138 }
139
140 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
141 struct ia64_psr *psr = ia64_psr(&scr->pt);
142
143 __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
144 psr->mfh = 0; /* drop signal handler's fph contents... */
145 if (psr->dfh)
146 ia64_drop_fpu(current);
147 else {
148 /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
149 __ia64_load_fpu(current->thread.fph);
150 ia64_set_local_fpu_owner(current);
151 }
152 }
153 return err;
154}
155
156int
157copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
158{
159 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
160 return -EFAULT;
161 if (from->si_code < 0) {
162 if (__copy_to_user(to, from, sizeof(siginfo_t)))
163 return -EFAULT;
164 return 0;
165 } else {
166 int err;
167
168 /*
169 * If you change siginfo_t structure, please be sure this code is fixed
170 * accordingly. It should never copy any pad contained in the structure
171 * to avoid security leaks, but must copy the generic 3 ints plus the
172 * relevant union member.
173 */
174 err = __put_user(from->si_signo, &to->si_signo);
175 err |= __put_user(from->si_errno, &to->si_errno);
176 err |= __put_user((short)from->si_code, &to->si_code);
177 switch (from->si_code >> 16) {
178 case __SI_FAULT >> 16:
179 err |= __put_user(from->si_flags, &to->si_flags);
180 err |= __put_user(from->si_isr, &to->si_isr);
181 case __SI_POLL >> 16:
182 err |= __put_user(from->si_addr, &to->si_addr);
183 err |= __put_user(from->si_imm, &to->si_imm);
184 break;
185 case __SI_TIMER >> 16:
186 err |= __put_user(from->si_tid, &to->si_tid);
187 err |= __put_user(from->si_overrun, &to->si_overrun);
188 err |= __put_user(from->si_ptr, &to->si_ptr);
189 break;
190 case __SI_RT >> 16: /* Not generated by the kernel as of now. */
191 case __SI_MESGQ >> 16:
192 err |= __put_user(from->si_uid, &to->si_uid);
193 err |= __put_user(from->si_pid, &to->si_pid);
194 err |= __put_user(from->si_ptr, &to->si_ptr);
195 break;
196 case __SI_CHLD >> 16:
197 err |= __put_user(from->si_utime, &to->si_utime);
198 err |= __put_user(from->si_stime, &to->si_stime);
199 err |= __put_user(from->si_status, &to->si_status);
200 default:
201 err |= __put_user(from->si_uid, &to->si_uid);
202 err |= __put_user(from->si_pid, &to->si_pid);
203 break;
204 }
205 return err;
206 }
207}
208
209long
210ia64_rt_sigreturn (struct sigscratch *scr)
211{
212 extern char ia64_strace_leave_kernel, ia64_leave_kernel;
213 struct sigcontext __user *sc;
214 struct siginfo si;
215 sigset_t set;
216 long retval;
217
218 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
219
220 /*
221 * When we return to the previously executing context, r8 and r10 have already
222 * been setup the way we want them. Indeed, if the signal wasn't delivered while
223 * in a system call, we must not touch r8 or r10 as otherwise user-level state
224 * could be corrupted.
225 */
226 retval = (long) &ia64_leave_kernel;
227 if (test_thread_flag(TIF_SYSCALL_TRACE))
228 /*
229 * strace expects to be notified after sigreturn returns even though the
230 * context to which we return may not be in the middle of a syscall.
231 * Thus, the return-value that strace displays for sigreturn is
232 * meaningless.
233 */
234 retval = (long) &ia64_strace_leave_kernel;
235
236 if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
237 goto give_sigsegv;
238
239 if (GET_SIGSET(&set, &sc->sc_mask))
240 goto give_sigsegv;
241
242 sigdelsetmask(&set, ~_BLOCKABLE);
243
244 spin_lock_irq(&current->sighand->siglock);
245 {
246 current->blocked = set;
247 recalc_sigpending();
248 }
249 spin_unlock_irq(&current->sighand->siglock);
250
251 if (restore_sigcontext(sc, scr))
252 goto give_sigsegv;
253
254#if DEBUG_SIG
255 printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
256 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
257#endif
258 /*
259 * It is more difficult to avoid calling this function than to
260 * call it and ignore errors.
261 */
262 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
263 return retval;
264
265 give_sigsegv:
266 si.si_signo = SIGSEGV;
267 si.si_errno = 0;
268 si.si_code = SI_KERNEL;
269 si.si_pid = current->pid;
270 si.si_uid = current->uid;
271 si.si_addr = sc;
272 force_sig_info(SIGSEGV, &si, current);
273 return retval;
274}
275
276/*
277 * This does just the minimum required setup of sigcontext.
278 * Specifically, it only installs data that is either not knowable at
279 * the user-level or that gets modified before execution in the
280 * trampoline starts. Everything else is done at the user-level.
281 */
282static long
283setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
284{
285 unsigned long flags = 0, ifs, cfm, nat;
286 long err;
287
288 ifs = scr->pt.cr_ifs;
289
290 if (on_sig_stack((unsigned long) sc))
291 flags |= IA64_SC_FLAG_ONSTACK;
292 if ((ifs & (1UL << 63)) == 0)
293 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
294 flags |= IA64_SC_FLAG_IN_SYSCALL;
295 cfm = ifs & ((1UL << 38) - 1);
296 ia64_flush_fph(current);
297 if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
298 flags |= IA64_SC_FLAG_FPH_VALID;
299 __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
300 }
301
302 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
303
304 err = __put_user(flags, &sc->sc_flags);
305 err |= __put_user(nat, &sc->sc_nat);
306 err |= PUT_SIGSET(mask, &sc->sc_mask);
307 err |= __put_user(cfm, &sc->sc_cfm);
308 err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
309 err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
310 err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
311 err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
312 err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
313 err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
314 err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
315 err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
316 err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
317 err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
318 err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
319 err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
320 err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
321
322 if (flags & IA64_SC_FLAG_IN_SYSCALL) {
323 /* Clear scratch registers if the signal interrupted a system call. */
324 err |= __put_user(0, &sc->sc_ar_ccv); /* ar.ccv */
325 err |= __put_user(0, &sc->sc_br[7]); /* b7 */
326 err |= __put_user(0, &sc->sc_gr[14]); /* r14 */
327 err |= __clear_user(&sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
328 err |= __clear_user(&sc->sc_gr[2], 2*8); /* r2-r3 */
329 err |= __clear_user(&sc->sc_gr[16], 16*8); /* r16-r31 */
330 } else {
331 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
332 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
333 err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
334 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
335 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
336 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
337 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
338 }
339 return err;
340}
341
342/*
343 * Check whether the register-backing store is already on the signal stack.
344 */
345static inline int
346rbs_on_sig_stack (unsigned long bsp)
347{
348 return (bsp - current->sas_ss_sp < current->sas_ss_size);
349}
350
351static long
352force_sigsegv_info (int sig, void __user *addr)
353{
354 unsigned long flags;
355 struct siginfo si;
356
357 if (sig == SIGSEGV) {
358 /*
359 * Acquiring siglock around the sa_handler-update is almost
360 * certainly overkill, but this isn't a
361 * performance-critical path and I'd rather play it safe
362 * here than having to debug a nasty race if and when
363 * something changes in kernel/signal.c that would make it
364 * no longer safe to modify sa_handler without holding the
365 * lock.
366 */
367 spin_lock_irqsave(&current->sighand->siglock, flags);
368 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
369 spin_unlock_irqrestore(&current->sighand->siglock, flags);
370 }
371 si.si_signo = SIGSEGV;
372 si.si_errno = 0;
373 si.si_code = SI_KERNEL;
374 si.si_pid = current->pid;
375 si.si_uid = current->uid;
376 si.si_addr = addr;
377 force_sig_info(SIGSEGV, &si, current);
378 return 0;
379}
380
381static long
382setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
383 struct sigscratch *scr)
384{
385 extern char __kernel_sigtramp[];
386 unsigned long tramp_addr, new_rbs = 0;
387 struct sigframe __user *frame;
388 long err;
389
390 frame = (void __user *) scr->pt.r12;
391 tramp_addr = (unsigned long) __kernel_sigtramp;
392 if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags((unsigned long) frame) == 0) {
393 frame = (void __user *) ((current->sas_ss_sp + current->sas_ss_size)
394 & ~(STACK_ALIGN - 1));
395 /*
396 * We need to check for the register stack being on the signal stack
397 * separately, because it's switched separately (memory stack is switched
398 * in the kernel, register stack is switched in the signal trampoline).
399 */
400 if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
401 new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
402 }
403 frame = (void __user *) frame - ((sizeof(*frame) + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1));
404
405 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
406 return force_sigsegv_info(sig, frame);
407
408 err = __put_user(sig, &frame->arg0);
409 err |= __put_user(&frame->info, &frame->arg1);
410 err |= __put_user(&frame->sc, &frame->arg2);
411 err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
412 err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
413 err |= __put_user(ka->sa.sa_handler, &frame->handler);
414
415 err |= copy_siginfo_to_user(&frame->info, info);
416
417 err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
418 err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
419 err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
420 err |= setup_sigcontext(&frame->sc, set, scr);
421
422 if (unlikely(err))
423 return force_sigsegv_info(sig, frame);
424
425 scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
426 scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
427 scr->pt.cr_iip = tramp_addr;
428 ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
429 ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */
430 /*
431 * Force the interruption function mask to zero. This has no effect when a
432 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
433 * ignored), but it has the desirable effect of making it possible to deliver a
434 * signal with an incomplete register frame (which happens when a mandatory RSE
435 * load faults). Furthermore, it has no negative effect on the getting the user's
436 * dirty partition preserved, because that's governed by scr->pt.loadrs.
437 */
438 scr->pt.cr_ifs = (1UL << 63);
439
440 /*
441 * Note: this affects only the NaT bits of the scratch regs (the ones saved in
442 * pt_regs), which is exactly what we want.
443 */
444 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
445
446#if DEBUG_SIG
447 printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
448 current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
449#endif
450 return 1;
451}
452
453static long
454handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
455 struct sigscratch *scr)
456{
457 if (IS_IA32_PROCESS(&scr->pt)) {
458 /* send signal to IA-32 process */
459 if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt))
460 return 0;
461 } else
462 /* send signal to IA-64 process */
463 if (!setup_frame(sig, ka, info, oldset, scr))
464 return 0;
465
466 if (!(ka->sa.sa_flags & SA_NODEFER)) {
467 spin_lock_irq(&current->sighand->siglock);
468 {
469 sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
470 sigaddset(&current->blocked, sig);
471 recalc_sigpending();
472 }
473 spin_unlock_irq(&current->sighand->siglock);
474 }
475 return 1;
476}
477
478/*
479 * Note that `init' is a special process: it doesn't get signals it doesn't want to
480 * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
481 */
482long
483ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
484{
485 struct k_sigaction ka;
486 siginfo_t info;
487 long restart = in_syscall;
488 long errno = scr->pt.r8;
489# define ERR_CODE(c) (IS_IA32_PROCESS(&scr->pt) ? -(c) : (c))
490
491 /*
492 * In the ia64_leave_kernel code path, we want the common case to go fast, which
493 * is why we may in certain cases get here from kernel mode. Just return without
494 * doing anything if so.
495 */
496 if (!user_mode(&scr->pt))
497 return 0;
498
499 if (!oldset)
500 oldset = &current->blocked;
501
502 /*
503 * This only loops in the rare cases of handle_signal() failing, in which case we
504 * need to push through a forced SIGSEGV.
505 */
506 while (1) {
507 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
508
509 /*
510 * get_signal_to_deliver() may have run a debugger (via notify_parent())
511 * and the debugger may have modified the state (e.g., to arrange for an
512 * inferior call), thus it's important to check for restarting _after_
513 * get_signal_to_deliver().
514 */
515 if (IS_IA32_PROCESS(&scr->pt)) {
516 if (in_syscall) {
517 if (errno >= 0)
518 restart = 0;
519 else
520 errno = -errno;
521 }
522 } else if ((long) scr->pt.r10 != -1)
523 /*
524 * A system calls has to be restarted only if one of the error codes
525 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
526 * isn't -1 then r8 doesn't hold an error code and we don't need to
527 * restart the syscall, so we can clear the "restart" flag here.
528 */
529 restart = 0;
530
531 if (signr <= 0)
532 break;
533
534 if (unlikely(restart)) {
535 switch (errno) {
536 case ERESTART_RESTARTBLOCK:
537 case ERESTARTNOHAND:
538 scr->pt.r8 = ERR_CODE(EINTR);
539 /* note: scr->pt.r10 is already -1 */
540 break;
541
542 case ERESTARTSYS:
543 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
544 scr->pt.r8 = ERR_CODE(EINTR);
545 /* note: scr->pt.r10 is already -1 */
546 break;
547 }
548 case ERESTARTNOINTR:
549 if (IS_IA32_PROCESS(&scr->pt)) {
550 scr->pt.r8 = scr->pt.r1;
551 scr->pt.cr_iip -= 2;
552 } else
553 ia64_decrement_ip(&scr->pt);
554 restart = 0; /* don't restart twice if handle_signal() fails... */
555 }
556 }
557
558 /*
559 * Whee! Actually deliver the signal. If the delivery failed, we need to
560 * continue to iterate in this loop so we can deliver the SIGSEGV...
561 */
562 if (handle_signal(signr, &ka, &info, oldset, scr))
563 return 1;
564 }
565
566 /* Did we come from a system call? */
567 if (restart) {
568 /* Restart the system call - no handlers present */
569 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
570 || errno == ERESTART_RESTARTBLOCK)
571 {
572 if (IS_IA32_PROCESS(&scr->pt)) {
573 scr->pt.r8 = scr->pt.r1;
574 scr->pt.cr_iip -= 2;
575 if (errno == ERESTART_RESTARTBLOCK)
576 scr->pt.r8 = 0; /* x86 version of __NR_restart_syscall */
577 } else {
578 /*
579 * Note: the syscall number is in r15 which is saved in
580 * pt_regs so all we need to do here is adjust ip so that
581 * the "break" instruction gets re-executed.
582 */
583 ia64_decrement_ip(&scr->pt);
584 if (errno == ERESTART_RESTARTBLOCK)
585 scr->pt.r15 = __NR_restart_syscall;
586 }
587 }
588 }
589 return 0;
590}
591
592/* Set a delayed signal that was detected in MCA/INIT/NMI/PMI context where it
593 * could not be delivered. It is important that the target process is not
594 * allowed to do any more work in user space. Possible cases for the target
595 * process:
596 *
597 * - It is sleeping and will wake up soon. Store the data in the current task,
598 * the signal will be sent when the current task returns from the next
599 * interrupt.
600 *
601 * - It is running in user context. Store the data in the current task, the
602 * signal will be sent when the current task returns from the next interrupt.
603 *
604 * - It is running in kernel context on this or another cpu and will return to
605 * user context. Store the data in the target task, the signal will be sent
606 * to itself when the target task returns to user space.
607 *
608 * - It is running in kernel context on this cpu and will sleep before
609 * returning to user context. Because this is also the current task, the
610 * signal will not get delivered and the task could sleep indefinitely.
611 * Store the data in the idle task for this cpu, the signal will be sent
612 * after the idle task processes its next interrupt.
613 *
614 * To cover all cases, store the data in the target task, the current task and
615 * the idle task on this cpu. Whatever happens, the signal will be delivered
616 * to the target task before it can do any useful user space work. Multiple
617 * deliveries have no unwanted side effects.
618 *
619 * Note: This code is executed in MCA/INIT/NMI/PMI context, with interrupts
620 * disabled. It must not take any locks nor use kernel structures or services
621 * that require locks.
622 */
623
624/* To ensure that we get the right pid, check its start time. To avoid extra
625 * include files in thread_info.h, convert the task start_time to unsigned long,
626 * giving us a cycle time of > 580 years.
627 */
628static inline unsigned long
629start_time_ul(const struct task_struct *t)
630{
631 return t->start_time.tv_sec * NSEC_PER_SEC + t->start_time.tv_nsec;
632}
633
634void
635set_sigdelayed(pid_t pid, int signo, int code, void __user *addr)
636{
637 struct task_struct *t;
638 unsigned long start_time = 0;
639 int i;
640
641 for (i = 1; i <= 3; ++i) {
642 switch (i) {
643 case 1:
644 t = find_task_by_pid(pid);
645 if (t)
646 start_time = start_time_ul(t);
647 break;
648 case 2:
649 t = current;
650 break;
651 default:
652 t = idle_task(smp_processor_id());
653 break;
654 }
655
656 if (!t)
657 return;
658 t->thread_info->sigdelayed.signo = signo;
659 t->thread_info->sigdelayed.code = code;
660 t->thread_info->sigdelayed.addr = addr;
661 t->thread_info->sigdelayed.start_time = start_time;
662 t->thread_info->sigdelayed.pid = pid;
663 wmb();
664 set_tsk_thread_flag(t, TIF_SIGDELAYED);
665 }
666}
667
668/* Called from entry.S when it detects TIF_SIGDELAYED, a delayed signal that
669 * was detected in MCA/INIT/NMI/PMI context where it could not be delivered.
670 */
671
672void
673do_sigdelayed(void)
674{
675 struct siginfo siginfo;
676 pid_t pid;
677 struct task_struct *t;
678
679 clear_thread_flag(TIF_SIGDELAYED);
680 memset(&siginfo, 0, sizeof(siginfo));
681 siginfo.si_signo = current_thread_info()->sigdelayed.signo;
682 siginfo.si_code = current_thread_info()->sigdelayed.code;
683 siginfo.si_addr = current_thread_info()->sigdelayed.addr;
684 pid = current_thread_info()->sigdelayed.pid;
685 t = find_task_by_pid(pid);
686 if (!t)
687 return;
688 if (current_thread_info()->sigdelayed.start_time != start_time_ul(t))
689 return;
690 force_sig_info(siginfo.si_signo, &siginfo, t);
691}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-29 14:24:34 -0500