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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * PA-RISC architecture-specific signal handling support.
4 *
5 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
6 * Copyright (C) 2000 Linuxcare, Inc.
7 * Copyright (C) 2000-2022 Helge Deller <deller@gmx.de>
8 * Copyright (C) 2022 John David Anglin <dave.anglin@bell.net>
9 *
10 * Based on the ia64, i386, and alpha versions.
11 */
12
13#include <linux/sched.h>
14#include <linux/sched/debug.h>
15#include <linux/mm.h>
16#include <linux/smp.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/errno.h>
20#include <linux/wait.h>
21#include <linux/ptrace.h>
22#include <linux/resume_user_mode.h>
23#include <linux/unistd.h>
24#include <linux/stddef.h>
25#include <linux/compat.h>
26#include <linux/elf.h>
27#include <asm/ucontext.h>
28#include <asm/rt_sigframe.h>
29#include <linux/uaccess.h>
30#include <asm/cacheflush.h>
31#include <asm/asm-offsets.h>
32#include <asm/vdso.h>
33
34#ifdef CONFIG_COMPAT
35#include "signal32.h"
36#endif
37
38#define DEBUG_SIG 0
39#define DEBUG_SIG_LEVEL 2
40
41#if DEBUG_SIG
42#define DBG(LEVEL, ...) \
43 ((DEBUG_SIG_LEVEL >= LEVEL) \
44 ? printk(__VA_ARGS__) : (void) 0)
45#else
46#define DBG(LEVEL, ...)
47#endif
48
49/* gcc will complain if a pointer is cast to an integer of different
50 * size. If you really need to do this (and we do for an ELF32 user
51 * application in an ELF64 kernel) then you have to do a cast to an
52 * integer of the same size first. The A() macro accomplishes
53 * this. */
54#define A(__x) ((unsigned long)(__x))
55
56/*
57 * Do a signal return - restore sigcontext.
58 */
59
60static long
61restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
62{
63 long err = 0;
64
65 err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
66 err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
67 err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
68 err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
69 err |= __get_user(regs->sar, &sc->sc_sar);
70 DBG(2, "%s: iaoq is %#lx / %#lx\n",
71 __func__, regs->iaoq[0], regs->iaoq[1]);
72 DBG(2, "%s: r28 is %ld\n", __func__, regs->gr[28]);
73 return err;
74}
75
76asmlinkage void
77sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
78{
79 struct rt_sigframe __user *frame;
80 sigset_t set;
81 unsigned long usp = (regs->gr[30] & ~(0x01UL));
82 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
83#ifdef CONFIG_64BIT
84 struct compat_rt_sigframe __user * compat_frame;
85
86 if (is_compat_task())
87 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
88#endif
89
90 current->restart_block.fn = do_no_restart_syscall;
91
92 /* Unwind the user stack to get the rt_sigframe structure. */
93 frame = (struct rt_sigframe __user *)
94 (usp - sigframe_size);
95 DBG(2, "%s: frame is %p pid %d\n", __func__, frame, task_pid_nr(current));
96
97 regs->orig_r28 = 1; /* no restarts for sigreturn */
98
99#ifdef CONFIG_64BIT
100 compat_frame = (struct compat_rt_sigframe __user *)frame;
101
102 if (is_compat_task()) {
103 if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
104 goto give_sigsegv;
105 } else
106#endif
107 {
108 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
109 goto give_sigsegv;
110 }
111
112 set_current_blocked(&set);
113
114 /* Good thing we saved the old gr[30], eh? */
115#ifdef CONFIG_64BIT
116 if (is_compat_task()) {
117 DBG(1, "%s: compat_frame->uc.uc_mcontext 0x%p\n",
118 __func__, &compat_frame->uc.uc_mcontext);
119// FIXME: Load upper half from register file
120 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
121 &compat_frame->regs, regs))
122 goto give_sigsegv;
123 DBG(1, "%s: usp %#08lx stack 0x%p\n",
124 __func__, usp, &compat_frame->uc.uc_stack);
125 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
126 goto give_sigsegv;
127 } else
128#endif
129 {
130 DBG(1, "%s: frame->uc.uc_mcontext 0x%p\n",
131 __func__, &frame->uc.uc_mcontext);
132 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
133 goto give_sigsegv;
134 DBG(1, "%s: usp %#08lx stack 0x%p\n",
135 __func__, usp, &frame->uc.uc_stack);
136 if (restore_altstack(&frame->uc.uc_stack))
137 goto give_sigsegv;
138 }
139
140
141
142 /* If we are on the syscall path IAOQ will not be restored, and
143 * if we are on the interrupt path we must not corrupt gr31.
144 */
145 if (in_syscall)
146 regs->gr[31] = regs->iaoq[0];
147
148 return;
149
150give_sigsegv:
151 DBG(1, "%s: Sending SIGSEGV\n", __func__);
152 force_sig(SIGSEGV);
153 return;
154}
155
156/*
157 * Set up a signal frame.
158 */
159
160static inline void __user *
161get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
162{
163 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
164 don't use the parameter it doesn't matter */
165
166 DBG(1, "%s: ka = %#lx, sp = %#lx, frame_size = %zu\n",
167 __func__, (unsigned long)ka, sp, frame_size);
168
169 /* Align alternate stack and reserve 64 bytes for the signal
170 handler's frame marker. */
171 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
172 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
173
174 DBG(1, "%s: Returning sp = %#lx\n", __func__, (unsigned long)sp);
175 return (void __user *) sp; /* Stacks grow up. Fun. */
176}
177
178static long
179setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, long in_syscall)
180
181{
182 unsigned long flags = 0;
183 long err = 0;
184
185 if (on_sig_stack((unsigned long) sc))
186 flags |= PARISC_SC_FLAG_ONSTACK;
187 if (in_syscall) {
188 flags |= PARISC_SC_FLAG_IN_SYSCALL;
189 /* regs->iaoq is undefined in the syscall return path */
190 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
191 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
192 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
193 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
194 DBG(1, "%s: iaoq %#lx / %#lx (in syscall)\n",
195 __func__, regs->gr[31], regs->gr[31]+4);
196 } else {
197 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
198 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
199 DBG(1, "%s: iaoq %#lx / %#lx (not in syscall)\n",
200 __func__, regs->iaoq[0], regs->iaoq[1]);
201 }
202
203 err |= __put_user(flags, &sc->sc_flags);
204 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
205 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
206 err |= __put_user(regs->sar, &sc->sc_sar);
207 DBG(1, "%s: r28 is %ld\n", __func__, regs->gr[28]);
208
209 return err;
210}
211
212static long
213setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
214 long in_syscall)
215{
216 struct rt_sigframe __user *frame;
217 unsigned long rp, usp;
218 unsigned long haddr, sigframe_size;
219 unsigned long start;
220 int err = 0;
221#ifdef CONFIG_64BIT
222 struct compat_rt_sigframe __user * compat_frame;
223#endif
224
225 usp = (regs->gr[30] & ~(0x01UL));
226 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
227#ifdef CONFIG_64BIT
228 if (is_compat_task()) {
229 /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
230 usp = (compat_uint_t)usp;
231 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
232 }
233#endif
234 frame = get_sigframe(&ksig->ka, usp, sigframe_size);
235
236 DBG(1, "%s: frame %p info %p\n", __func__, frame, &ksig->info);
237
238 start = (unsigned long) frame;
239 if (start >= TASK_SIZE_MAX - sigframe_size)
240 return -EFAULT;
241
242#ifdef CONFIG_64BIT
243
244 compat_frame = (struct compat_rt_sigframe __user *)frame;
245
246 if (is_compat_task()) {
247 DBG(1, "%s: frame->info = 0x%p\n", __func__, &compat_frame->info);
248 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
249 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
250 DBG(1, "%s: frame->uc = 0x%p\n", __func__, &compat_frame->uc);
251 DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
252 __func__, &compat_frame->uc.uc_mcontext);
253 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
254 &compat_frame->regs, regs, in_syscall);
255 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
256 sizeof(compat_sigset_t));
257 } else
258#endif
259 {
260 DBG(1, "%s: frame->info = 0x%p\n", __func__, &frame->info);
261 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
262 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
263 DBG(1, "%s: frame->uc = 0x%p\n", __func__, &frame->uc);
264 DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
265 __func__, &frame->uc.uc_mcontext);
266 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
267 /* FIXME: Should probably be converted as well for the compat case */
268 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
269 }
270
271 if (err)
272 return -EFAULT;
273
274#ifdef CONFIG_64BIT
275 if (!is_compat_task())
276 rp = VDSO64_SYMBOL(current, sigtramp_rt);
277 else
278#endif
279 rp = VDSO32_SYMBOL(current, sigtramp_rt);
280
281 if (in_syscall)
282 rp += 4*4; /* skip 4 instructions and start at ldi 1,%r25 */
283
284 haddr = A(ksig->ka.sa.sa_handler);
285 /* The sa_handler may be a pointer to a function descriptor */
286#ifdef CONFIG_64BIT
287 if (is_compat_task()) {
288#endif
289 if (haddr & PA_PLABEL_FDESC) {
290 Elf32_Fdesc fdesc;
291 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
292
293 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
294
295 if (err)
296 return -EFAULT;
297
298 haddr = fdesc.addr;
299 regs->gr[19] = fdesc.gp;
300 }
301#ifdef CONFIG_64BIT
302 } else {
303 Elf64_Fdesc fdesc;
304 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
305
306 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
307
308 if (err)
309 return -EFAULT;
310
311 haddr = fdesc.addr;
312 regs->gr[19] = fdesc.gp;
313 DBG(1, "%s: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
314 __func__, haddr, regs->gr[19], in_syscall);
315 }
316#endif
317
318 /* The syscall return path will create IAOQ values from r31.
319 */
320 if (in_syscall) {
321 regs->gr[31] = haddr;
322#ifdef CONFIG_64BIT
323 if (!test_thread_flag(TIF_32BIT))
324 sigframe_size |= 1; /* XXX ???? */
325#endif
326 } else {
327 unsigned long psw = USER_PSW;
328#ifdef CONFIG_64BIT
329 if (!test_thread_flag(TIF_32BIT))
330 psw |= PSW_W;
331#endif
332
333 /* If we are singlestepping, arrange a trap to be delivered
334 when we return to userspace. Note the semantics -- we
335 should trap before the first insn in the handler is
336 executed. Ref:
337 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
338 */
339 if (pa_psw(current)->r) {
340 pa_psw(current)->r = 0;
341 psw |= PSW_R;
342 mtctl(-1, 0);
343 }
344
345 regs->gr[0] = psw;
346 regs->iaoq[0] = haddr | PRIV_USER;
347 regs->iaoq[1] = regs->iaoq[0] + 4;
348 }
349
350 regs->gr[2] = rp; /* userland return pointer */
351 regs->gr[26] = ksig->sig; /* signal number */
352
353#ifdef CONFIG_64BIT
354 if (is_compat_task()) {
355 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
356 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
357 } else
358#endif
359 {
360 regs->gr[25] = A(&frame->info); /* siginfo pointer */
361 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
362 }
363
364 DBG(1, "%s: making sigreturn frame: %#lx + %#lx = %#lx\n", __func__,
365 regs->gr[30], sigframe_size,
366 regs->gr[30] + sigframe_size);
367 /* Raise the user stack pointer to make a proper call frame. */
368 regs->gr[30] = (A(frame) + sigframe_size);
369
370
371 DBG(1, "%s: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
372 __func__, current->comm, current->pid, frame, regs->gr[30],
373 regs->iaoq[0], regs->iaoq[1], rp);
374
375 return 0;
376}
377
378/*
379 * OK, we're invoking a handler.
380 */
381
382static void
383handle_signal(struct ksignal *ksig, struct pt_regs *regs, long in_syscall)
384{
385 int ret;
386 sigset_t *oldset = sigmask_to_save();
387
388 DBG(1, "%s: sig=%d, ka=%p, info=%p, oldset=%p, regs=%p\n",
389 __func__, ksig->sig, &ksig->ka, &ksig->info, oldset, regs);
390
391 /* Set up the stack frame */
392 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
393
394 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
395 test_thread_flag(TIF_BLOCKSTEP));
396
397 DBG(1, "%s: Exit (success), regs->gr[28] = %ld\n",
398 __func__, regs->gr[28]);
399}
400
401/*
402 * Check how the syscall number gets loaded into %r20 within
403 * the delay branch in userspace and adjust as needed.
404 */
405
406static void check_syscallno_in_delay_branch(struct pt_regs *regs)
407{
408 u32 opcode, source_reg;
409 u32 __user *uaddr;
410 int err;
411
412 /* Usually we don't have to restore %r20 (the system call number)
413 * because it gets loaded in the delay slot of the branch external
414 * instruction via the ldi instruction.
415 * In some cases a register-to-register copy instruction might have
416 * been used instead, in which case we need to copy the syscall
417 * number into the source register before returning to userspace.
418 */
419
420 /* A syscall is just a branch, so all we have to do is fiddle the
421 * return pointer so that the ble instruction gets executed again.
422 */
423 regs->gr[31] -= 8; /* delayed branching */
424
425 /* Get assembler opcode of code in delay branch */
426 uaddr = (u32 __user *) ((regs->gr[31] & ~3) + 4);
427 err = get_user(opcode, uaddr);
428 if (err)
429 return;
430
431 /* Check if delay branch uses "ldi int,%r20" */
432 if ((opcode & 0xffff0000) == 0x34140000)
433 return; /* everything ok, just return */
434
435 /* Check if delay branch uses "nop" */
436 if (opcode == INSN_NOP)
437 return;
438
439 /* Check if delay branch uses "copy %rX,%r20" */
440 if ((opcode & 0xffe0ffff) == 0x08000254) {
441 source_reg = (opcode >> 16) & 31;
442 regs->gr[source_reg] = regs->gr[20];
443 return;
444 }
445
446 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
447 current->comm, task_pid_nr(current), opcode);
448}
449
450static inline void
451syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
452{
453 if (regs->orig_r28)
454 return;
455 regs->orig_r28 = 1; /* no more restarts */
456
457 DBG(1, "%s: orig_r28 = %ld pid %d r20 %ld\n",
458 __func__, regs->orig_r28, task_pid_nr(current), regs->gr[20]);
459
460 /* Check the return code */
461 switch (regs->gr[28]) {
462 case -ERESTART_RESTARTBLOCK:
463 case -ERESTARTNOHAND:
464 DBG(1, "%s: ERESTARTNOHAND: returning -EINTR\n", __func__);
465 regs->gr[28] = -EINTR;
466 break;
467 case -ERESTARTSYS:
468 if (!(ka->sa.sa_flags & SA_RESTART)) {
469 DBG(1, "%s: ERESTARTSYS: putting -EINTR pid %d\n",
470 __func__, task_pid_nr(current));
471 regs->gr[28] = -EINTR;
472 break;
473 }
474 fallthrough;
475 case -ERESTARTNOINTR:
476 DBG(1, "%s: %ld\n", __func__, regs->gr[28]);
477 check_syscallno_in_delay_branch(regs);
478 break;
479 }
480}
481
482static inline void
483insert_restart_trampoline(struct pt_regs *regs)
484{
485 if (regs->orig_r28)
486 return;
487 regs->orig_r28 = 1; /* no more restarts */
488
489 DBG(2, "%s: gr28 = %ld pid %d\n",
490 __func__, regs->gr[28], task_pid_nr(current));
491
492 switch (regs->gr[28]) {
493 case -ERESTART_RESTARTBLOCK: {
494 /* Restart the system call - no handlers present */
495 unsigned int *usp = (unsigned int *)regs->gr[30];
496 unsigned long rp;
497 long err = 0;
498
499 /* check that we don't exceed the stack */
500 if (A(&usp[0]) >= TASK_SIZE_MAX - 5 * sizeof(int))
501 return;
502
503 /* Call trampoline in vdso to restart the syscall
504 * with __NR_restart_syscall.
505 * Original return addresses are on stack like this:
506 *
507 * 0: <return address (orig r31)>
508 * 4: <2nd half for 64-bit>
509 */
510#ifdef CONFIG_64BIT
511 if (!is_compat_task()) {
512 err |= put_user(regs->gr[31] >> 32, &usp[0]);
513 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
514 rp = VDSO64_SYMBOL(current, restart_syscall);
515 } else
516#endif
517 {
518 err |= put_user(regs->gr[31], &usp[0]);
519 rp = VDSO32_SYMBOL(current, restart_syscall);
520 }
521 WARN_ON(err);
522
523 regs->gr[31] = rp;
524 DBG(1, "%s: ERESTART_RESTARTBLOCK\n", __func__);
525 return;
526 }
527 case -EINTR:
528 /* ok, was handled before and should be returned. */
529 break;
530 case -ERESTARTNOHAND:
531 case -ERESTARTSYS:
532 case -ERESTARTNOINTR:
533 DBG(1, "%s: Type %ld\n", __func__, regs->gr[28]);
534 check_syscallno_in_delay_branch(regs);
535 return;
536 default:
537 break;
538 }
539}
540
541/*
542 * We need to be able to restore the syscall arguments (r21-r26) to
543 * restart syscalls. Thus, the syscall path should save them in the
544 * pt_regs structure (it's okay to do so since they are caller-save
545 * registers). As noted below, the syscall number gets restored for
546 * us due to the magic of delayed branching.
547 */
548static void do_signal(struct pt_regs *regs, long in_syscall)
549{
550 struct ksignal ksig;
551 int restart_syscall;
552 bool has_handler;
553
554 has_handler = get_signal(&ksig);
555
556 restart_syscall = 0;
557 if (in_syscall)
558 restart_syscall = 1;
559
560 if (has_handler) {
561 /* Restart a system call if necessary. */
562 if (restart_syscall)
563 syscall_restart(regs, &ksig.ka);
564
565 handle_signal(&ksig, regs, in_syscall);
566 DBG(1, "%s: Handled signal pid %d\n",
567 __func__, task_pid_nr(current));
568 return;
569 }
570
571 /* Do we need to restart the system call? */
572 if (restart_syscall)
573 insert_restart_trampoline(regs);
574
575 DBG(1, "%s: Exit (not delivered), regs->gr[28] = %ld orig_r28 = %ld pid %d\n",
576 __func__, regs->gr[28], regs->orig_r28, task_pid_nr(current));
577
578 restore_saved_sigmask();
579}
580
581asmlinkage void do_notify_resume(struct pt_regs *regs, long in_syscall)
582{
583 if (test_thread_flag(TIF_SIGPENDING) ||
584 test_thread_flag(TIF_NOTIFY_SIGNAL))
585 do_signal(regs, in_syscall);
586
587 if (test_thread_flag(TIF_NOTIFY_RESUME))
588 resume_user_mode_work(regs);
589}