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[PATCH] powerpc: work around a cell interrupt HW bug
[deliverable/linux.git] / arch / powerpc / kernel / signal_64.c
CommitLineData
1da177e4 1/*
1da177e4
LT		 2 * PowerPC version
3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4 *
5 * Derived from "arch/i386/kernel/signal.c"
6 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15#include <linux/config.h>
16#include <linux/sched.h>
17#include <linux/mm.h>
18#include <linux/smp.h>
19#include <linux/smp_lock.h>
20#include <linux/kernel.h>
21#include <linux/signal.h>
22#include <linux/errno.h>
23#include <linux/wait.h>
24#include <linux/unistd.h>
25#include <linux/stddef.h>
26#include <linux/elf.h>
27#include <linux/ptrace.h>
28#include <linux/module.h>
29
30#include <asm/sigcontext.h>
31#include <asm/ucontext.h>
32#include <asm/uaccess.h>
33#include <asm/pgtable.h>
1da177e4
LT		 34#include <asm/unistd.h>
35#include <asm/cacheflush.h>
36#include <asm/vdso.h>
37
38#define DEBUG_SIG 0
39
40#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
41
6741f3a7 42#define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
1da177e4
LT		 43#define FP_REGS_SIZE sizeof(elf_fpregset_t)
44
45#define TRAMP_TRACEBACK 3
46#define TRAMP_SIZE 6
47
48/*
49 * When we have signals to deliver, we set up on the user stack,
50 * going down from the original stack pointer:
51 * 1) a rt_sigframe struct which contains the ucontext
52 * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
53 * frame for the signal handler.
54 */
55
56struct rt_sigframe {
57 /* sys_rt_sigreturn requires the ucontext be the first field */
58 struct ucontext uc;
59 unsigned long _unused[2];
60 unsigned int tramp[TRAMP_SIZE];
29e646df
AV		 61 struct siginfo __user *pinfo;
62 void __user *puc;
1da177e4
LT		 63 struct siginfo info;
64 /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
65 char abigap[288];
66} __attribute__ ((aligned (16)));
67
1da177e4
LT		 68long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5,
69 unsigned long r6, unsigned long r7, unsigned long r8,
70 struct pt_regs *regs)
71{
72 return do_sigaltstack(uss, uoss, regs->gpr[1]);
73}
74
75
76/*
77 * Set up the sigcontext for the signal frame.
78 */
79
80static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
81 int signr, sigset_t *set, unsigned long handler)
82{
83 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
84 * process never used altivec yet (MSR_VEC is zero in pt_regs of
85 * the context). This is very important because we must ensure we
86 * don't lose the VRSAVE content that may have been set prior to
87 * the process doing its first vector operation
88 * Userland shall check AT_HWCAP to know wether it can rely on the
89 * v_regs pointer or not
90 */
91#ifdef CONFIG_ALTIVEC
92 elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
93#endif
94 long err = 0;
95
96 flush_fp_to_thread(current);
97
1da177e4
LT		 98#ifdef CONFIG_ALTIVEC
99 err |= __put_user(v_regs, &sc->v_regs);
100
101 /* save altivec registers */
102 if (current->thread.used_vr) {
103 flush_altivec_to_thread(current);
104 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
105 err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
106 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
107 * contains valid data.
108 */
109 regs->msr |= MSR_VEC;
110 }
111 /* We always copy to/from vrsave, it's 0 if we don't have or don't
112 * use altivec.
113 */
114 err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
115#else /* CONFIG_ALTIVEC */
116 err |= __put_user(0, &sc->v_regs);
117#endif /* CONFIG_ALTIVEC */
118 err |= __put_user(&sc->gp_regs, &sc->regs);
1bd79336 119 WARN_ON(!FULL_REGS(regs));
1da177e4
LT		 120 err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
121 err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
122 err |= __put_user(signr, &sc->signal);
123 err |= __put_user(handler, &sc->handler);
124 if (set != NULL)
125 err |= __put_user(set->sig[0], &sc->oldmask);
126
127 return err;
128}
129
130/*
131 * Restore the sigcontext from the signal frame.
132 */
133
134static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
135 struct sigcontext __user *sc)
136{
137#ifdef CONFIG_ALTIVEC
138 elf_vrreg_t __user *v_regs;
139#endif
140 unsigned long err = 0;
141 unsigned long save_r13 = 0;
142 elf_greg_t *gregs = (elf_greg_t *)regs;
143#ifdef CONFIG_ALTIVEC
144 unsigned long msr;
145#endif
146 int i;
147
148 /* If this is not a signal return, we preserve the TLS in r13 */
149 if (!sig)
150 save_r13 = regs->gpr[13];
151
152 /* copy everything before MSR */
153 err |= __copy_from_user(regs, &sc->gp_regs,
154 PT_MSR*sizeof(unsigned long));
155
156 /* skip MSR and SOFTE */
157 for (i = PT_MSR+1; i <= PT_RESULT; i++) {
158 if (i == PT_SOFTE)
159 continue;
160 err |= __get_user(gregs[i], &sc->gp_regs[i]);
161 }
162
163 if (!sig)
164 regs->gpr[13] = save_r13;
1da177e4
LT		 165 if (set != NULL)
166 err |= __get_user(set->sig[0], &sc->oldmask);
167
5388fb10
PM		 168 /*
169 * Do this before updating the thread state in
170 * current->thread.fpr/vr. That way, if we get preempted
171 * and another task grabs the FPU/Altivec, it won't be
172 * tempted to save the current CPU state into the thread_struct
173 * and corrupt what we are writing there.
174 */
175 discard_lazy_cpu_state();
176
177 err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
178
1da177e4
LT		 179#ifdef CONFIG_ALTIVEC
180 err |= __get_user(v_regs, &sc->v_regs);
181 err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
182 if (err)
183 return err;
184 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
185 if (v_regs != 0 && (msr & MSR_VEC) != 0)
186 err |= __copy_from_user(current->thread.vr, v_regs,
187 33 * sizeof(vector128));
188 else if (current->thread.used_vr)
189 memset(current->thread.vr, 0, 33 * sizeof(vector128));
190 /* Always get VRSAVE back */
191 if (v_regs != 0)
192 err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
193 else
194 current->thread.vrsave = 0;
195#endif /* CONFIG_ALTIVEC */
196
1da177e4
LT		 197 /* Force reload of FP/VEC */
198 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
199
200 return err;
201}
202
203/*
204 * Allocate space for the signal frame
205 */
206static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
207 size_t frame_size)
208{
209 unsigned long newsp;
210
211 /* Default to using normal stack */
212 newsp = regs->gpr[1];
213
214 if (ka->sa.sa_flags & SA_ONSTACK) {
215 if (! on_sig_stack(regs->gpr[1]))
216 newsp = (current->sas_ss_sp + current->sas_ss_size);
217 }
218
219 return (void __user *)((newsp - frame_size) & -16ul);
220}
221
222/*
223 * Setup the trampoline code on the stack
224 */
225static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
226{
227 int i;
228 long err = 0;
229
230 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
231 err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
232 /* li r0, __NR_[rt_]sigreturn| */
233 err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
234 /* sc */
235 err |= __put_user(0x44000002UL, &tramp[2]);
236
237 /* Minimal traceback info */
238 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
239 err |= __put_user(0, &tramp[i]);
240
241 if (!err)
242 flush_icache_range((unsigned long) &tramp[0],
243 (unsigned long) &tramp[TRAMP_SIZE]);
244
245 return err;
246}
247
248/*
249 * Restore the user process's signal mask (also used by signal32.c)
250 */
251void restore_sigmask(sigset_t *set)
252{
253 sigdelsetmask(set, ~_BLOCKABLE);
254 spin_lock_irq(&current->sighand->siglock);
255 current->blocked = *set;
256 recalc_sigpending();
257 spin_unlock_irq(&current->sighand->siglock);
258}
259
260
261/*
262 * Handle {get,set,swap}_context operations
263 */
264int sys_swapcontext(struct ucontext __user *old_ctx,
265 struct ucontext __user *new_ctx,
266 long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
267{
268 unsigned char tmp;
269 sigset_t set;
270
271 /* Context size is for future use. Right now, we only make sure
272 * we are passed something we understand
273 */
274 if (ctx_size < sizeof(struct ucontext))
275 return -EINVAL;
276
277 if (old_ctx != NULL) {
278 if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
279 || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
280 || __copy_to_user(&old_ctx->uc_sigmask,
281 &current->blocked, sizeof(sigset_t)))
282 return -EFAULT;
283 }
284 if (new_ctx == NULL)
285 return 0;
286 if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
287 || __get_user(tmp, (u8 __user *) new_ctx)
288 || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
289 return -EFAULT;
290
291 /*
292 * If we get a fault copying the context into the kernel's
293 * image of the user's registers, we can't just return -EFAULT
294 * because the user's registers will be corrupted. For instance
295 * the NIP value may have been updated but not some of the
296 * other registers. Given that we have done the access_ok
297 * and successfully read the first and last bytes of the region
298 * above, this should only happen in an out-of-memory situation
299 * or if another thread unmaps the region containing the context.
300 * We kill the task with a SIGSEGV in this situation.
301 */
302
303 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
304 do_exit(SIGSEGV);
305 restore_sigmask(&set);
306 if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
307 do_exit(SIGSEGV);
308
309 /* This returns like rt_sigreturn */
401d1f02 310 set_thread_flag(TIF_RESTOREALL);
1da177e4
LT		 311 return 0;
312}
313
314
315/*
316 * Do a signal return; undo the signal stack.
317 */
318
319int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
320 unsigned long r6, unsigned long r7, unsigned long r8,
321 struct pt_regs *regs)
322{
323 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
324 sigset_t set;
325
326 /* Always make any pending restarted system calls return -EINTR */
327 current_thread_info()->restart_block.fn = do_no_restart_syscall;
328
329 if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
330 goto badframe;
331
332 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
333 goto badframe;
334 restore_sigmask(&set);
335 if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
336 goto badframe;
337
338 /* do_sigaltstack expects a __user pointer and won't modify
339 * what's in there anyway
340 */
341 do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
342
401d1f02
DW		 343 set_thread_flag(TIF_RESTOREALL);
344 return 0;
1da177e4
LT		 345
346badframe:
347#if DEBUG_SIG
348 printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
349 regs, uc, &uc->uc_mcontext);
350#endif
351 force_sig(SIGSEGV, current);
352 return 0;
353}
354
355static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
356 sigset_t *set, struct pt_regs *regs)
357{
358 /* Handler is *really* a pointer to the function descriptor for
359 * the signal routine. The first entry in the function
360 * descriptor is the entry address of signal and the second
361 * entry is the TOC value we need to use.
362 */
363 func_descr_t __user *funct_desc_ptr;
364 struct rt_sigframe __user *frame;
365 unsigned long newsp = 0;
366 long err = 0;
367
368 frame = get_sigframe(ka, regs, sizeof(*frame));
369
370 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
371 goto badframe;
372
373 err |= __put_user(&frame->info, &frame->pinfo);
374 err |= __put_user(&frame->uc, &frame->puc);
375 err |= copy_siginfo_to_user(&frame->info, info);
376 if (err)
377 goto badframe;
378
379 /* Create the ucontext. */
380 err |= __put_user(0, &frame->uc.uc_flags);
381 err |= __put_user(0, &frame->uc.uc_link);
382 err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
383 err |= __put_user(sas_ss_flags(regs->gpr[1]),
384 &frame->uc.uc_stack.ss_flags);
385 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
386 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
387 (unsigned long)ka->sa.sa_handler);
388 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
389 if (err)
390 goto badframe;
391
cc657f53
PM		 392 /* Make sure signal handler doesn't get spurious FP exceptions */
393 current->thread.fpscr.val = 0;
394
1da177e4
LT		 395 /* Set up to return from userspace. */
396 if (vdso64_rt_sigtramp && current->thread.vdso_base) {
397 regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
398 } else {
399 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
400 if (err)
401 goto badframe;
402 regs->link = (unsigned long) &frame->tramp[0];
403 }
404 funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
405
406 /* Allocate a dummy caller frame for the signal handler. */
407 newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;
408 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
409
410 /* Set up "regs" so we "return" to the signal handler. */
411 err |= get_user(regs->nip, &funct_desc_ptr->entry);
412 regs->gpr[1] = newsp;
413 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
414 regs->gpr[3] = signr;
415 regs->result = 0;
416 if (ka->sa.sa_flags & SA_SIGINFO) {
417 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
418 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
419 regs->gpr[6] = (unsigned long) frame;
420 } else {
421 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
422 }
423 if (err)
424 goto badframe;
425
1da177e4
LT		 426 return 1;
427
428badframe:
429#if DEBUG_SIG
430 printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
431 regs, frame, newsp);
432#endif
433 force_sigsegv(signr, current);
434 return 0;
435}
436
437
438/*
439 * OK, we're invoking a handler
440 */
441static int handle_signal(unsigned long sig, struct k_sigaction *ka,
442 siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
443{
444 int ret;
445
446 /* Set up Signal Frame */
447 ret = setup_rt_frame(sig, ka, info, oldset, regs);
448
69be8f18 449 if (ret) {
1da177e4
LT		 450 spin_lock_irq(&current->sighand->siglock);
451 sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
69be8f18
SR		 452 if (!(ka->sa.sa_flags & SA_NODEFER))
453 sigaddset(&current->blocked,sig);
1da177e4
LT		 454 recalc_sigpending();
455 spin_unlock_irq(&current->sighand->siglock);
456 }
457
458 return ret;
459}
460
461static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
462{
463 switch ((int)regs->result) {
464 case -ERESTART_RESTARTBLOCK:
465 case -ERESTARTNOHAND:
466 /* ERESTARTNOHAND means that the syscall should only be
467 * restarted if there was no handler for the signal, and since
468 * we only get here if there is a handler, we dont restart.
469 */
470 regs->result = -EINTR;
401d1f02
DW		 471 regs->gpr[3] = EINTR;
472 regs->ccr |= 0x10000000;
1da177e4
LT		 473 break;
474 case -ERESTARTSYS:
475 /* ERESTARTSYS means to restart the syscall if there is no
476 * handler or the handler was registered with SA_RESTART
477 */
478 if (!(ka->sa.sa_flags & SA_RESTART)) {
479 regs->result = -EINTR;
401d1f02
DW		 480 regs->gpr[3] = EINTR;
481 regs->ccr |= 0x10000000;
1da177e4
LT		 482 break;
483 }
484 /* fallthrough */
485 case -ERESTARTNOINTR:
486 /* ERESTARTNOINTR means that the syscall should be
487 * called again after the signal handler returns.
488 */
489 regs->gpr[3] = regs->orig_gpr3;
490 regs->nip -= 4;
491 regs->result = 0;
492 break;
493 }
494}
495
496/*
497 * Note that 'init' is a special process: it doesn't get signals it doesn't
498 * want to handle. Thus you cannot kill init even with a SIGKILL even by
499 * mistake.
500 */
501int do_signal(sigset_t *oldset, struct pt_regs *regs)
502{
503 siginfo_t info;
504 int signr;
505 struct k_sigaction ka;
506
507 /*
508 * If the current thread is 32 bit - invoke the
509 * 32 bit signal handling code
510 */
511 if (test_thread_flag(TIF_32BIT))
512 return do_signal32(oldset, regs);
513
f27201da
DW		 514 if (test_thread_flag(TIF_RESTORE_SIGMASK))
515 oldset = &current->saved_sigmask;
516 else if (!oldset)
1da177e4
LT		 517 oldset = &current->blocked;
518
519 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
520 if (signr > 0) {
f27201da
DW		 521 int ret;
522
1da177e4
LT		 523 /* Whee! Actually deliver the signal. */
524 if (TRAP(regs) == 0x0C00)
525 syscall_restart(regs, &ka);
fd9648df
AB		 526
527 /*
528 * Reenable the DABR before delivering the signal to
529 * user space. The DABR will have been cleared if it
530 * triggered inside the kernel.
531 */
532 if (current->thread.dabr)
533 set_dabr(current->thread.dabr);
534
f27201da
DW		 535 ret = handle_signal(signr, &ka, &info, oldset, regs);
536
537 /* If a signal was successfully delivered, the saved sigmask is in
538 its frame, and we can clear the TIF_RESTORE_SIGMASK flag */
539 if (ret && test_thread_flag(TIF_RESTORE_SIGMASK))
540 clear_thread_flag(TIF_RESTORE_SIGMASK);
541
542 return ret;
1da177e4
LT		 543 }
544
545 if (TRAP(regs) == 0x0C00) { /* System Call! */
546 if ((int)regs->result == -ERESTARTNOHAND ||
547 (int)regs->result == -ERESTARTSYS ||
548 (int)regs->result == -ERESTARTNOINTR) {
549 regs->gpr[3] = regs->orig_gpr3;
550 regs->nip -= 4; /* Back up & retry system call */
551 regs->result = 0;
552 } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
553 regs->gpr[0] = __NR_restart_syscall;
554 regs->nip -= 4;
555 regs->result = 0;
556 }
557 }
f27201da
DW		 558 /* No signal to deliver -- put the saved sigmask back */
559 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
560 clear_thread_flag(TIF_RESTORE_SIGMASK);
561 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
562 }
1da177e4
LT		 563
564 return 0;
565}
566EXPORT_SYMBOL(do_signal);
Linux kernel - Deliverables
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