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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/parisc/kernel/signal.c: Architecture-specific signal
4 * handling support.
5 *
6 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
7 * Copyright (C) 2000 Linuxcare, Inc.
8 *
9 * Based on the ia64, i386, and alpha versions.
10 *
11 * Like the IA-64, we are a recent enough port (we are *starting*
12 * with glibc2.2) that we do not need to support the old non-realtime
13 * Linux signals. Therefore we don't.
14 */
15
16#include <linux/sched.h>
17#include <linux/sched/debug.h>
18#include <linux/mm.h>
19#include <linux/smp.h>
20#include <linux/kernel.h>
21#include <linux/signal.h>
22#include <linux/errno.h>
23#include <linux/wait.h>
24#include <linux/ptrace.h>
25#include <linux/tracehook.h>
26#include <linux/unistd.h>
27#include <linux/stddef.h>
28#include <linux/compat.h>
29#include <linux/elf.h>
30#include <asm/ucontext.h>
31#include <asm/rt_sigframe.h>
32#include <linux/uaccess.h>
33#include <asm/cacheflush.h>
34#include <asm/asm-offsets.h>
35
36#ifdef CONFIG_COMPAT
37#include "signal32.h"
38#endif
39
40#define DEBUG_SIG 0
41#define DEBUG_SIG_LEVEL 2
42
43#if DEBUG_SIG
44#define DBG(LEVEL, ...) \
45 ((DEBUG_SIG_LEVEL >= LEVEL) \
46 ? printk(__VA_ARGS__) : (void) 0)
47#else
48#define DBG(LEVEL, ...)
49#endif
50
51/* gcc will complain if a pointer is cast to an integer of different
52 * size. If you really need to do this (and we do for an ELF32 user
53 * application in an ELF64 kernel) then you have to do a cast to an
54 * integer of the same size first. The A() macro accomplishes
55 * this. */
56#define A(__x) ((unsigned long)(__x))
57
58/*
59 * Do a signal return - restore sigcontext.
60 */
61
62/* Trampoline for calling rt_sigreturn() */
63#define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */
64#define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */
65#define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */
66#define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
67/* For debugging */
68#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
69
70static long
71restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
72{
73 long err = 0;
74
75 err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
76 err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
77 err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
78 err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
79 err |= __get_user(regs->sar, &sc->sc_sar);
80 DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
81 regs->iaoq[0],regs->iaoq[1]);
82 DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
83 return err;
84}
85
86void
87sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
88{
89 struct rt_sigframe __user *frame;
90 sigset_t set;
91 unsigned long usp = (regs->gr[30] & ~(0x01UL));
92 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
93#ifdef CONFIG_64BIT
94 struct compat_rt_sigframe __user * compat_frame;
95
96 if (is_compat_task())
97 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
98#endif
99
100 current->restart_block.fn = do_no_restart_syscall;
101
102 /* Unwind the user stack to get the rt_sigframe structure. */
103 frame = (struct rt_sigframe __user *)
104 (usp - sigframe_size);
105 DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
106
107 regs->orig_r28 = 1; /* no restarts for sigreturn */
108
109#ifdef CONFIG_64BIT
110 compat_frame = (struct compat_rt_sigframe __user *)frame;
111
112 if (is_compat_task()) {
113 DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
114 if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
115 goto give_sigsegv;
116 } else
117#endif
118 {
119 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
120 goto give_sigsegv;
121 }
122
123 set_current_blocked(&set);
124
125 /* Good thing we saved the old gr[30], eh? */
126#ifdef CONFIG_64BIT
127 if (is_compat_task()) {
128 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
129 &compat_frame->uc.uc_mcontext);
130// FIXME: Load upper half from register file
131 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
132 &compat_frame->regs, regs))
133 goto give_sigsegv;
134 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
135 usp, &compat_frame->uc.uc_stack);
136 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
137 goto give_sigsegv;
138 } else
139#endif
140 {
141 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
142 &frame->uc.uc_mcontext);
143 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
144 goto give_sigsegv;
145 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
146 usp, &frame->uc.uc_stack);
147 if (restore_altstack(&frame->uc.uc_stack))
148 goto give_sigsegv;
149 }
150
151
152
153 /* If we are on the syscall path IAOQ will not be restored, and
154 * if we are on the interrupt path we must not corrupt gr31.
155 */
156 if (in_syscall)
157 regs->gr[31] = regs->iaoq[0];
158#if DEBUG_SIG
159 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
160 show_regs(regs);
161#endif
162 return;
163
164give_sigsegv:
165 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
166 force_sig(SIGSEGV);
167 return;
168}
169
170/*
171 * Set up a signal frame.
172 */
173
174static inline void __user *
175get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
176{
177 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
178 don't use the parameter it doesn't matter */
179
180 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
181 (unsigned long)ka, sp, frame_size);
182
183 /* Align alternate stack and reserve 64 bytes for the signal
184 handler's frame marker. */
185 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
186 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
187
188 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
189 return (void __user *) sp; /* Stacks grow up. Fun. */
190}
191
192static long
193setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
194
195{
196 unsigned long flags = 0;
197 long err = 0;
198
199 if (on_sig_stack((unsigned long) sc))
200 flags |= PARISC_SC_FLAG_ONSTACK;
201 if (in_syscall) {
202 flags |= PARISC_SC_FLAG_IN_SYSCALL;
203 /* regs->iaoq is undefined in the syscall return path */
204 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
205 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
206 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
207 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
208 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
209 regs->gr[31], regs->gr[31]+4);
210 } else {
211 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
212 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
213 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n",
214 regs->iaoq[0], regs->iaoq[1]);
215 }
216
217 err |= __put_user(flags, &sc->sc_flags);
218 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
219 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
220 err |= __put_user(regs->sar, &sc->sc_sar);
221 DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
222
223 return err;
224}
225
226static long
227setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
228 int in_syscall)
229{
230 struct rt_sigframe __user *frame;
231 unsigned long rp, usp;
232 unsigned long haddr, sigframe_size;
233 unsigned long start, end;
234 int err = 0;
235#ifdef CONFIG_64BIT
236 struct compat_rt_sigframe __user * compat_frame;
237#endif
238
239 usp = (regs->gr[30] & ~(0x01UL));
240 /*FIXME: frame_size parameter is unused, remove it. */
241 frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
242
243 DBG(1,"SETUP_RT_FRAME: START\n");
244 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
245
246
247#ifdef CONFIG_64BIT
248
249 compat_frame = (struct compat_rt_sigframe __user *)frame;
250
251 if (is_compat_task()) {
252 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
253 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
254 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
255 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
256 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
257 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
258 &compat_frame->regs, regs, in_syscall);
259 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
260 sizeof(compat_sigset_t));
261 } else
262#endif
263 {
264 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
265 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
266 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
267 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
268 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
269 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
270 /* FIXME: Should probably be converted as well for the compat case */
271 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
272 }
273
274 if (err)
275 return -EFAULT;
276
277 /* Set up to return from userspace. If provided, use a stub
278 already in userspace. The first words of tramp are used to
279 save the previous sigrestartblock trampoline that might be
280 on the stack. We start the sigreturn trampoline at
281 SIGRESTARTBLOCK_TRAMP+X. */
282 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
283 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
284 err |= __put_user(INSN_LDI_R20,
285 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
286 err |= __put_user(INSN_BLE_SR2_R0,
287 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
288 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
289
290#if DEBUG_SIG
291 /* Assert that we're flushing in the correct space... */
292 {
293 unsigned long sid;
294 asm ("mfsp %%sr3,%0" : "=r" (sid));
295 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
296 sid, frame->tramp);
297 }
298#endif
299
300 start = (unsigned long) &frame->tramp[0];
301 end = (unsigned long) &frame->tramp[TRAMP_SIZE];
302 flush_user_dcache_range_asm(start, end);
303 flush_user_icache_range_asm(start, end);
304
305 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
306 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
307 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
308 */
309 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
310
311 if (err)
312 return -EFAULT;
313
314 haddr = A(ksig->ka.sa.sa_handler);
315 /* The sa_handler may be a pointer to a function descriptor */
316#ifdef CONFIG_64BIT
317 if (is_compat_task()) {
318#endif
319 if (haddr & PA_PLABEL_FDESC) {
320 Elf32_Fdesc fdesc;
321 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
322
323 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
324
325 if (err)
326 return -EFAULT;
327
328 haddr = fdesc.addr;
329 regs->gr[19] = fdesc.gp;
330 }
331#ifdef CONFIG_64BIT
332 } else {
333 Elf64_Fdesc fdesc;
334 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
335
336 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
337
338 if (err)
339 return -EFAULT;
340
341 haddr = fdesc.addr;
342 regs->gr[19] = fdesc.gp;
343 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
344 haddr, regs->gr[19], in_syscall);
345 }
346#endif
347
348 /* The syscall return path will create IAOQ values from r31.
349 */
350 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
351#ifdef CONFIG_64BIT
352 if (is_compat_task())
353 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
354#endif
355 if (in_syscall) {
356 regs->gr[31] = haddr;
357#ifdef CONFIG_64BIT
358 if (!test_thread_flag(TIF_32BIT))
359 sigframe_size |= 1;
360#endif
361 } else {
362 unsigned long psw = USER_PSW;
363#ifdef CONFIG_64BIT
364 if (!test_thread_flag(TIF_32BIT))
365 psw |= PSW_W;
366#endif
367
368 /* If we are singlestepping, arrange a trap to be delivered
369 when we return to userspace. Note the semantics -- we
370 should trap before the first insn in the handler is
371 executed. Ref:
372 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
373 */
374 if (pa_psw(current)->r) {
375 pa_psw(current)->r = 0;
376 psw |= PSW_R;
377 mtctl(-1, 0);
378 }
379
380 regs->gr[0] = psw;
381 regs->iaoq[0] = haddr | 3;
382 regs->iaoq[1] = regs->iaoq[0] + 4;
383 }
384
385 regs->gr[2] = rp; /* userland return pointer */
386 regs->gr[26] = ksig->sig; /* signal number */
387
388#ifdef CONFIG_64BIT
389 if (is_compat_task()) {
390 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
391 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
392 } else
393#endif
394 {
395 regs->gr[25] = A(&frame->info); /* siginfo pointer */
396 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
397 }
398
399 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
400 regs->gr[30], sigframe_size,
401 regs->gr[30] + sigframe_size);
402 /* Raise the user stack pointer to make a proper call frame. */
403 regs->gr[30] = (A(frame) + sigframe_size);
404
405
406 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
407 current->comm, current->pid, frame, regs->gr[30],
408 regs->iaoq[0], regs->iaoq[1], rp);
409
410 return 0;
411}
412
413/*
414 * OK, we're invoking a handler.
415 */
416
417static void
418handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
419{
420 int ret;
421 sigset_t *oldset = sigmask_to_save();
422
423 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
424 ksig->sig, ksig->ka, ksig->info, oldset, regs);
425
426 /* Set up the stack frame */
427 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
428
429 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
430 test_thread_flag(TIF_BLOCKSTEP));
431
432 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
433 regs->gr[28]);
434}
435
436/*
437 * Check how the syscall number gets loaded into %r20 within
438 * the delay branch in userspace and adjust as needed.
439 */
440
441static void check_syscallno_in_delay_branch(struct pt_regs *regs)
442{
443 u32 opcode, source_reg;
444 u32 __user *uaddr;
445 int err;
446
447 /* Usually we don't have to restore %r20 (the system call number)
448 * because it gets loaded in the delay slot of the branch external
449 * instruction via the ldi instruction.
450 * In some cases a register-to-register copy instruction might have
451 * been used instead, in which case we need to copy the syscall
452 * number into the source register before returning to userspace.
453 */
454
455 /* A syscall is just a branch, so all we have to do is fiddle the
456 * return pointer so that the ble instruction gets executed again.
457 */
458 regs->gr[31] -= 8; /* delayed branching */
459
460 /* Get assembler opcode of code in delay branch */
461 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
462 err = get_user(opcode, uaddr);
463 if (err)
464 return;
465
466 /* Check if delay branch uses "ldi int,%r20" */
467 if ((opcode & 0xffff0000) == 0x34140000)
468 return; /* everything ok, just return */
469
470 /* Check if delay branch uses "nop" */
471 if (opcode == INSN_NOP)
472 return;
473
474 /* Check if delay branch uses "copy %rX,%r20" */
475 if ((opcode & 0xffe0ffff) == 0x08000254) {
476 source_reg = (opcode >> 16) & 31;
477 regs->gr[source_reg] = regs->gr[20];
478 return;
479 }
480
481 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
482 current->comm, task_pid_nr(current), opcode);
483}
484
485static inline void
486syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
487{
488 if (regs->orig_r28)
489 return;
490 regs->orig_r28 = 1; /* no more restarts */
491 /* Check the return code */
492 switch (regs->gr[28]) {
493 case -ERESTART_RESTARTBLOCK:
494 case -ERESTARTNOHAND:
495 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
496 regs->gr[28] = -EINTR;
497 break;
498
499 case -ERESTARTSYS:
500 if (!(ka->sa.sa_flags & SA_RESTART)) {
501 DBG(1,"ERESTARTSYS: putting -EINTR\n");
502 regs->gr[28] = -EINTR;
503 break;
504 }
505 fallthrough;
506 case -ERESTARTNOINTR:
507 check_syscallno_in_delay_branch(regs);
508 break;
509 }
510}
511
512static inline void
513insert_restart_trampoline(struct pt_regs *regs)
514{
515 if (regs->orig_r28)
516 return;
517 regs->orig_r28 = 1; /* no more restarts */
518 switch(regs->gr[28]) {
519 case -ERESTART_RESTARTBLOCK: {
520 /* Restart the system call - no handlers present */
521 unsigned int *usp = (unsigned int *)regs->gr[30];
522 unsigned long start = (unsigned long) &usp[2];
523 unsigned long end = (unsigned long) &usp[5];
524 long err = 0;
525
526 /* Setup a trampoline to restart the syscall
527 * with __NR_restart_syscall
528 *
529 * 0: <return address (orig r31)>
530 * 4: <2nd half for 64-bit>
531 * 8: ldw 0(%sp), %r31
532 * 12: be 0x100(%sr2, %r0)
533 * 16: ldi __NR_restart_syscall, %r20
534 */
535#ifdef CONFIG_64BIT
536 err |= put_user(regs->gr[31] >> 32, &usp[0]);
537 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
538 err |= put_user(0x0fc010df, &usp[2]);
539#else
540 err |= put_user(regs->gr[31], &usp[0]);
541 err |= put_user(0x0fc0109f, &usp[2]);
542#endif
543 err |= put_user(0xe0008200, &usp[3]);
544 err |= put_user(0x34140000, &usp[4]);
545
546 WARN_ON(err);
547
548 /* flush data/instruction cache for new insns */
549 flush_user_dcache_range_asm(start, end);
550 flush_user_icache_range_asm(start, end);
551
552 regs->gr[31] = regs->gr[30] + 8;
553 return;
554 }
555 case -ERESTARTNOHAND:
556 case -ERESTARTSYS:
557 case -ERESTARTNOINTR:
558 check_syscallno_in_delay_branch(regs);
559 return;
560 default:
561 break;
562 }
563}
564
565/*
566 * Note that 'init' is a special process: it doesn't get signals it doesn't
567 * want to handle. Thus you cannot kill init even with a SIGKILL even by
568 * mistake.
569 *
570 * We need to be able to restore the syscall arguments (r21-r26) to
571 * restart syscalls. Thus, the syscall path should save them in the
572 * pt_regs structure (it's okay to do so since they are caller-save
573 * registers). As noted below, the syscall number gets restored for
574 * us due to the magic of delayed branching.
575 */
576asmlinkage void
577do_signal(struct pt_regs *regs, long in_syscall)
578{
579 struct ksignal ksig;
580
581 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
582 regs, regs->sr[7], in_syscall);
583
584 if (get_signal(&ksig)) {
585 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
586 /* Restart a system call if necessary. */
587 if (in_syscall)
588 syscall_restart(regs, &ksig.ka);
589
590 handle_signal(&ksig, regs, in_syscall);
591 return;
592 }
593
594 /* Did we come from a system call? */
595 if (in_syscall)
596 insert_restart_trampoline(regs);
597
598 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
599 regs->gr[28]);
600
601 restore_saved_sigmask();
602}
603
604void do_notify_resume(struct pt_regs *regs, long in_syscall)
605{
606 if (test_thread_flag(TIF_SIGPENDING))
607 do_signal(regs, in_syscall);
608
609 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
610 clear_thread_flag(TIF_NOTIFY_RESUME);
611 tracehook_notify_resume(regs);
612 }
613}
1/*
2 * linux/arch/parisc/kernel/signal.c: Architecture-specific signal
3 * handling support.
4 *
5 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
6 * Copyright (C) 2000 Linuxcare, Inc.
7 *
8 * Based on the ia64, i386, and alpha versions.
9 *
10 * Like the IA-64, we are a recent enough port (we are *starting*
11 * with glibc2.2) that we do not need to support the old non-realtime
12 * Linux signals. Therefore we don't. HP/UX signals will go in
13 * arch/parisc/hpux/signal.c when we figure out how to do them.
14 */
15
16#include <linux/sched.h>
17#include <linux/mm.h>
18#include <linux/smp.h>
19#include <linux/kernel.h>
20#include <linux/signal.h>
21#include <linux/errno.h>
22#include <linux/wait.h>
23#include <linux/ptrace.h>
24#include <linux/tracehook.h>
25#include <linux/unistd.h>
26#include <linux/stddef.h>
27#include <linux/compat.h>
28#include <linux/elf.h>
29#include <asm/ucontext.h>
30#include <asm/rt_sigframe.h>
31#include <asm/uaccess.h>
32#include <asm/pgalloc.h>
33#include <asm/cacheflush.h>
34#include <asm/asm-offsets.h>
35
36#ifdef CONFIG_COMPAT
37#include "signal32.h"
38#endif
39
40#define DEBUG_SIG 0
41#define DEBUG_SIG_LEVEL 2
42
43#if DEBUG_SIG
44#define DBG(LEVEL, ...) \
45 ((DEBUG_SIG_LEVEL >= LEVEL) \
46 ? printk(__VA_ARGS__) : (void) 0)
47#else
48#define DBG(LEVEL, ...)
49#endif
50
51/* gcc will complain if a pointer is cast to an integer of different
52 * size. If you really need to do this (and we do for an ELF32 user
53 * application in an ELF64 kernel) then you have to do a cast to an
54 * integer of the same size first. The A() macro accomplishes
55 * this. */
56#define A(__x) ((unsigned long)(__x))
57
58/*
59 * Do a signal return - restore sigcontext.
60 */
61
62/* Trampoline for calling rt_sigreturn() */
63#define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */
64#define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */
65#define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */
66#define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
67#define INSN_NOP 0x08000240 /* nop */
68/* For debugging */
69#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
70
71static long
72restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
73{
74 long err = 0;
75
76 err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
77 err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
78 err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
79 err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
80 err |= __get_user(regs->sar, &sc->sc_sar);
81 DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
82 regs->iaoq[0],regs->iaoq[1]);
83 DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
84 return err;
85}
86
87void
88sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
89{
90 struct rt_sigframe __user *frame;
91 sigset_t set;
92 unsigned long usp = (regs->gr[30] & ~(0x01UL));
93 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
94#ifdef CONFIG_64BIT
95 compat_sigset_t compat_set;
96 struct compat_rt_sigframe __user * compat_frame;
97
98 if (is_compat_task())
99 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
100#endif
101
102 current_thread_info()->restart_block.fn = do_no_restart_syscall;
103
104 /* Unwind the user stack to get the rt_sigframe structure. */
105 frame = (struct rt_sigframe __user *)
106 (usp - sigframe_size);
107 DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
108
109 regs->orig_r28 = 1; /* no restarts for sigreturn */
110
111#ifdef CONFIG_64BIT
112 compat_frame = (struct compat_rt_sigframe __user *)frame;
113
114 if (is_compat_task()) {
115 DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
116 if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set)))
117 goto give_sigsegv;
118 sigset_32to64(&set,&compat_set);
119 } else
120#endif
121 {
122 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
123 goto give_sigsegv;
124 }
125
126 set_current_blocked(&set);
127
128 /* Good thing we saved the old gr[30], eh? */
129#ifdef CONFIG_64BIT
130 if (is_compat_task()) {
131 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
132 &compat_frame->uc.uc_mcontext);
133// FIXME: Load upper half from register file
134 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
135 &compat_frame->regs, regs))
136 goto give_sigsegv;
137 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
138 usp, &compat_frame->uc.uc_stack);
139 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
140 goto give_sigsegv;
141 } else
142#endif
143 {
144 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
145 &frame->uc.uc_mcontext);
146 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
147 goto give_sigsegv;
148 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
149 usp, &frame->uc.uc_stack);
150 if (restore_altstack(&frame->uc.uc_stack))
151 goto give_sigsegv;
152 }
153
154
155
156 /* If we are on the syscall path IAOQ will not be restored, and
157 * if we are on the interrupt path we must not corrupt gr31.
158 */
159 if (in_syscall)
160 regs->gr[31] = regs->iaoq[0];
161#if DEBUG_SIG
162 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
163 show_regs(regs);
164#endif
165 return;
166
167give_sigsegv:
168 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
169 force_sig(SIGSEGV, current);
170 return;
171}
172
173/*
174 * Set up a signal frame.
175 */
176
177static inline void __user *
178get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
179{
180 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
181 don't use the parameter it doesn't matter */
182
183 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
184 (unsigned long)ka, sp, frame_size);
185
186 /* Align alternate stack and reserve 64 bytes for the signal
187 handler's frame marker. */
188 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
189 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
190
191 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
192 return (void __user *) sp; /* Stacks grow up. Fun. */
193}
194
195static long
196setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
197
198{
199 unsigned long flags = 0;
200 long err = 0;
201
202 if (on_sig_stack((unsigned long) sc))
203 flags |= PARISC_SC_FLAG_ONSTACK;
204 if (in_syscall) {
205 flags |= PARISC_SC_FLAG_IN_SYSCALL;
206 /* regs->iaoq is undefined in the syscall return path */
207 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
208 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
209 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
210 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
211 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
212 regs->gr[31], regs->gr[31]+4);
213 } else {
214 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
215 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
216 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n",
217 regs->iaoq[0], regs->iaoq[1]);
218 }
219
220 err |= __put_user(flags, &sc->sc_flags);
221 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
222 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
223 err |= __put_user(regs->sar, &sc->sc_sar);
224 DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
225
226 return err;
227}
228
229static long
230setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
231 sigset_t *set, struct pt_regs *regs, int in_syscall)
232{
233 struct rt_sigframe __user *frame;
234 unsigned long rp, usp;
235 unsigned long haddr, sigframe_size;
236 int err = 0;
237#ifdef CONFIG_64BIT
238 struct compat_rt_sigframe __user * compat_frame;
239 compat_sigset_t compat_set;
240#endif
241
242 usp = (regs->gr[30] & ~(0x01UL));
243 /*FIXME: frame_size parameter is unused, remove it. */
244 frame = get_sigframe(ka, usp, sizeof(*frame));
245
246 DBG(1,"SETUP_RT_FRAME: START\n");
247 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, info);
248
249
250#ifdef CONFIG_64BIT
251
252 compat_frame = (struct compat_rt_sigframe __user *)frame;
253
254 if (is_compat_task()) {
255 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
256 err |= copy_siginfo_to_user32(&compat_frame->info, info);
257 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
258 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
259 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
260 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
261 &compat_frame->regs, regs, in_syscall);
262 sigset_64to32(&compat_set,set);
263 err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set));
264 } else
265#endif
266 {
267 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
268 err |= copy_siginfo_to_user(&frame->info, info);
269 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
270 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
271 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
272 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
273 /* FIXME: Should probably be converted as well for the compat case */
274 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
275 }
276
277 if (err)
278 goto give_sigsegv;
279
280 /* Set up to return from userspace. If provided, use a stub
281 already in userspace. The first words of tramp are used to
282 save the previous sigrestartblock trampoline that might be
283 on the stack. We start the sigreturn trampoline at
284 SIGRESTARTBLOCK_TRAMP+X. */
285 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
286 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
287 err |= __put_user(INSN_LDI_R20,
288 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
289 err |= __put_user(INSN_BLE_SR2_R0,
290 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
291 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
292
293#if DEBUG_SIG
294 /* Assert that we're flushing in the correct space... */
295 {
296 unsigned long sid;
297 asm ("mfsp %%sr3,%0" : "=r" (sid));
298 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
299 sid, frame->tramp);
300 }
301#endif
302
303 flush_user_dcache_range((unsigned long) &frame->tramp[0],
304 (unsigned long) &frame->tramp[TRAMP_SIZE]);
305 flush_user_icache_range((unsigned long) &frame->tramp[0],
306 (unsigned long) &frame->tramp[TRAMP_SIZE]);
307
308 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
309 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
310 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
311 */
312 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
313
314 if (err)
315 goto give_sigsegv;
316
317 haddr = A(ka->sa.sa_handler);
318 /* The sa_handler may be a pointer to a function descriptor */
319#ifdef CONFIG_64BIT
320 if (is_compat_task()) {
321#endif
322 if (haddr & PA_PLABEL_FDESC) {
323 Elf32_Fdesc fdesc;
324 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
325
326 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
327
328 if (err)
329 goto give_sigsegv;
330
331 haddr = fdesc.addr;
332 regs->gr[19] = fdesc.gp;
333 }
334#ifdef CONFIG_64BIT
335 } else {
336 Elf64_Fdesc fdesc;
337 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
338
339 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
340
341 if (err)
342 goto give_sigsegv;
343
344 haddr = fdesc.addr;
345 regs->gr[19] = fdesc.gp;
346 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
347 haddr, regs->gr[19], in_syscall);
348 }
349#endif
350
351 /* The syscall return path will create IAOQ values from r31.
352 */
353 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
354#ifdef CONFIG_64BIT
355 if (is_compat_task())
356 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
357#endif
358 if (in_syscall) {
359 regs->gr[31] = haddr;
360#ifdef CONFIG_64BIT
361 if (!test_thread_flag(TIF_32BIT))
362 sigframe_size |= 1;
363#endif
364 } else {
365 unsigned long psw = USER_PSW;
366#ifdef CONFIG_64BIT
367 if (!test_thread_flag(TIF_32BIT))
368 psw |= PSW_W;
369#endif
370
371 /* If we are singlestepping, arrange a trap to be delivered
372 when we return to userspace. Note the semantics -- we
373 should trap before the first insn in the handler is
374 executed. Ref:
375 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
376 */
377 if (pa_psw(current)->r) {
378 pa_psw(current)->r = 0;
379 psw |= PSW_R;
380 mtctl(-1, 0);
381 }
382
383 regs->gr[0] = psw;
384 regs->iaoq[0] = haddr | 3;
385 regs->iaoq[1] = regs->iaoq[0] + 4;
386 }
387
388 regs->gr[2] = rp; /* userland return pointer */
389 regs->gr[26] = sig; /* signal number */
390
391#ifdef CONFIG_64BIT
392 if (is_compat_task()) {
393 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
394 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
395 } else
396#endif
397 {
398 regs->gr[25] = A(&frame->info); /* siginfo pointer */
399 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
400 }
401
402 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
403 regs->gr[30], sigframe_size,
404 regs->gr[30] + sigframe_size);
405 /* Raise the user stack pointer to make a proper call frame. */
406 regs->gr[30] = (A(frame) + sigframe_size);
407
408
409 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
410 current->comm, current->pid, frame, regs->gr[30],
411 regs->iaoq[0], regs->iaoq[1], rp);
412
413 return 1;
414
415give_sigsegv:
416 DBG(1,"setup_rt_frame: sending SIGSEGV\n");
417 force_sigsegv(sig, current);
418 return 0;
419}
420
421/*
422 * OK, we're invoking a handler.
423 */
424
425static void
426handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
427 struct pt_regs *regs, int in_syscall)
428{
429 sigset_t *oldset = sigmask_to_save();
430 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
431 sig, ka, info, oldset, regs);
432
433 /* Set up the stack frame */
434 if (!setup_rt_frame(sig, ka, info, oldset, regs, in_syscall))
435 return;
436
437 signal_delivered(sig, info, ka, regs,
438 test_thread_flag(TIF_SINGLESTEP) ||
439 test_thread_flag(TIF_BLOCKSTEP));
440
441 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
442 regs->gr[28]);
443}
444
445static inline void
446syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
447{
448 if (regs->orig_r28)
449 return;
450 regs->orig_r28 = 1; /* no more restarts */
451 /* Check the return code */
452 switch (regs->gr[28]) {
453 case -ERESTART_RESTARTBLOCK:
454 case -ERESTARTNOHAND:
455 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
456 regs->gr[28] = -EINTR;
457 break;
458
459 case -ERESTARTSYS:
460 if (!(ka->sa.sa_flags & SA_RESTART)) {
461 DBG(1,"ERESTARTSYS: putting -EINTR\n");
462 regs->gr[28] = -EINTR;
463 break;
464 }
465 /* fallthrough */
466 case -ERESTARTNOINTR:
467 /* A syscall is just a branch, so all
468 * we have to do is fiddle the return pointer.
469 */
470 regs->gr[31] -= 8; /* delayed branching */
471 break;
472 }
473}
474
475static inline void
476insert_restart_trampoline(struct pt_regs *regs)
477{
478 if (regs->orig_r28)
479 return;
480 regs->orig_r28 = 1; /* no more restarts */
481 switch(regs->gr[28]) {
482 case -ERESTART_RESTARTBLOCK: {
483 /* Restart the system call - no handlers present */
484 unsigned int *usp = (unsigned int *)regs->gr[30];
485
486 /* Setup a trampoline to restart the syscall
487 * with __NR_restart_syscall
488 *
489 * 0: <return address (orig r31)>
490 * 4: <2nd half for 64-bit>
491 * 8: ldw 0(%sp), %r31
492 * 12: be 0x100(%sr2, %r0)
493 * 16: ldi __NR_restart_syscall, %r20
494 */
495#ifdef CONFIG_64BIT
496 put_user(regs->gr[31] >> 32, &usp[0]);
497 put_user(regs->gr[31] & 0xffffffff, &usp[1]);
498 put_user(0x0fc010df, &usp[2]);
499#else
500 put_user(regs->gr[31], &usp[0]);
501 put_user(0x0fc0109f, &usp[2]);
502#endif
503 put_user(0xe0008200, &usp[3]);
504 put_user(0x34140000, &usp[4]);
505
506 /* Stack is 64-byte aligned, and we only need
507 * to flush 1 cache line.
508 * Flushing one cacheline is cheap.
509 * "sync" on bigger (> 4 way) boxes is not.
510 */
511 flush_user_dcache_range(regs->gr[30], regs->gr[30] + 4);
512 flush_user_icache_range(regs->gr[30], regs->gr[30] + 4);
513
514 regs->gr[31] = regs->gr[30] + 8;
515 return;
516 }
517 case -ERESTARTNOHAND:
518 case -ERESTARTSYS:
519 case -ERESTARTNOINTR: {
520 /* Hooray for delayed branching. We don't
521 * have to restore %r20 (the system call
522 * number) because it gets loaded in the delay
523 * slot of the branch external instruction.
524 */
525 regs->gr[31] -= 8;
526 return;
527 }
528 default:
529 break;
530 }
531}
532
533/*
534 * Note that 'init' is a special process: it doesn't get signals it doesn't
535 * want to handle. Thus you cannot kill init even with a SIGKILL even by
536 * mistake.
537 *
538 * We need to be able to restore the syscall arguments (r21-r26) to
539 * restart syscalls. Thus, the syscall path should save them in the
540 * pt_regs structure (it's okay to do so since they are caller-save
541 * registers). As noted below, the syscall number gets restored for
542 * us due to the magic of delayed branching.
543 */
544asmlinkage void
545do_signal(struct pt_regs *regs, long in_syscall)
546{
547 siginfo_t info;
548 struct k_sigaction ka;
549 int signr;
550
551 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
552 regs, regs->sr[7], in_syscall);
553
554 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
555 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
556
557 if (signr > 0) {
558 /* Restart a system call if necessary. */
559 if (in_syscall)
560 syscall_restart(regs, &ka);
561
562 handle_signal(signr, &info, &ka, regs, in_syscall);
563 return;
564 }
565
566 /* Did we come from a system call? */
567 if (in_syscall)
568 insert_restart_trampoline(regs);
569
570 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
571 regs->gr[28]);
572
573 restore_saved_sigmask();
574}
575
576void do_notify_resume(struct pt_regs *regs, long in_syscall)
577{
578 if (test_thread_flag(TIF_SIGPENDING))
579 do_signal(regs, in_syscall);
580
581 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
582 clear_thread_flag(TIF_NOTIFY_RESUME);
583 tracehook_notify_resume(regs);
584 }
585}