1 // SPDX-License-Identifier: GPL-2.0
3 * linux/arch/parisc/kernel/signal.c: Architecture-specific signal
6 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
7 * Copyright (C) 2000 Linuxcare, Inc.
9 * Based on the ia64, i386, and alpha versions.
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.
16 #include <linux/sched.h>
17 #include <linux/sched/debug.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>
41 #define DEBUG_SIG_LEVEL 2
44 #define DBG(LEVEL, ...) \
45 ((DEBUG_SIG_LEVEL >= LEVEL) \
46 ? printk(__VA_ARGS__) : (void) 0)
48 #define DBG(LEVEL, ...)
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
56 #define A(__x) ((unsigned long)(__x))
59 * Do a signal return - restore sigcontext.
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 */
68 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
71 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
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]);
87 sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
89 struct rt_sigframe __user *frame;
91 unsigned long usp = (regs->gr[30] & ~(0x01UL));
92 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
94 struct compat_rt_sigframe __user * compat_frame;
97 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
100 current->restart_block.fn = do_no_restart_syscall;
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);
107 regs->orig_r28 = 1; /* no restarts for sigreturn */
110 compat_frame = (struct compat_rt_sigframe __user *)frame;
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))
119 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
123 set_current_blocked(&set);
125 /* Good thing we saved the old gr[30], eh? */
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))
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))
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))
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))
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.
157 regs->gr[31] = regs->iaoq[0];
159 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
165 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
171 * Set up a signal frame.
174 static inline void __user *
175 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
177 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
178 don't use the parameter it doesn't matter */
180 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
181 (unsigned long)ka, sp, frame_size);
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! */
188 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
189 return (void __user *) sp; /* Stacks grow up. Fun. */
193 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
196 unsigned long flags = 0;
199 if (on_sig_stack((unsigned long) sc))
200 flags |= PARISC_SC_FLAG_ONSTACK;
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);
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]);
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]);
227 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
230 struct rt_sigframe __user *frame;
231 unsigned long rp, usp;
232 unsigned long haddr, sigframe_size;
233 unsigned long start, end;
236 struct compat_rt_sigframe __user * compat_frame;
239 usp = (regs->gr[30] & ~(0x01UL));
240 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
242 if (is_compat_task()) {
243 /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
244 usp = (compat_uint_t)usp;
245 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
248 frame = get_sigframe(&ksig->ka, usp, sigframe_size);
250 DBG(1,"SETUP_RT_FRAME: START\n");
251 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
253 start = (unsigned long) frame;
254 if (start >= user_addr_max() - sigframe_size)
259 compat_frame = (struct compat_rt_sigframe __user *)frame;
261 if (is_compat_task()) {
262 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
263 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
264 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
265 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
266 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
267 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
268 &compat_frame->regs, regs, in_syscall);
269 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
270 sizeof(compat_sigset_t));
274 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
275 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
276 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
277 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
278 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
279 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
280 /* FIXME: Should probably be converted as well for the compat case */
281 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
287 /* Set up to return from userspace. If provided, use a stub
288 already in userspace. The first words of tramp are used to
289 save the previous sigrestartblock trampoline that might be
290 on the stack. We start the sigreturn trampoline at
291 SIGRESTARTBLOCK_TRAMP+X. */
292 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
293 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
294 err |= __put_user(INSN_LDI_R20,
295 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
296 err |= __put_user(INSN_BLE_SR2_R0,
297 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
298 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
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);
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
309 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
314 haddr = A(ksig->ka.sa.sa_handler);
315 /* The sa_handler may be a pointer to a function descriptor */
317 if (is_compat_task()) {
319 if (haddr & PA_PLABEL_FDESC) {
321 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
323 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
329 regs->gr[19] = fdesc.gp;
334 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
336 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
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);
348 /* The syscall return path will create IAOQ values from r31.
351 regs->gr[31] = haddr;
353 if (!test_thread_flag(TIF_32BIT))
357 unsigned long psw = USER_PSW;
359 if (!test_thread_flag(TIF_32BIT))
363 /* If we are singlestepping, arrange a trap to be delivered
364 when we return to userspace. Note the semantics -- we
365 should trap before the first insn in the handler is
367 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
369 if (pa_psw(current)->r) {
370 pa_psw(current)->r = 0;
376 regs->iaoq[0] = haddr | 3;
377 regs->iaoq[1] = regs->iaoq[0] + 4;
380 regs->gr[2] = rp; /* userland return pointer */
381 regs->gr[26] = ksig->sig; /* signal number */
384 if (is_compat_task()) {
385 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
386 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
390 regs->gr[25] = A(&frame->info); /* siginfo pointer */
391 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
394 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
395 regs->gr[30], sigframe_size,
396 regs->gr[30] + sigframe_size);
397 /* Raise the user stack pointer to make a proper call frame. */
398 regs->gr[30] = (A(frame) + sigframe_size);
401 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
402 current->comm, current->pid, frame, regs->gr[30],
403 regs->iaoq[0], regs->iaoq[1], rp);
409 * OK, we're invoking a handler.
413 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
416 sigset_t *oldset = sigmask_to_save();
418 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
419 ksig->sig, ksig->ka, ksig->info, oldset, regs);
421 /* Set up the stack frame */
422 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
424 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
425 test_thread_flag(TIF_BLOCKSTEP));
427 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
432 * Check how the syscall number gets loaded into %r20 within
433 * the delay branch in userspace and adjust as needed.
436 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
438 u32 opcode, source_reg;
442 /* Usually we don't have to restore %r20 (the system call number)
443 * because it gets loaded in the delay slot of the branch external
444 * instruction via the ldi instruction.
445 * In some cases a register-to-register copy instruction might have
446 * been used instead, in which case we need to copy the syscall
447 * number into the source register before returning to userspace.
450 /* A syscall is just a branch, so all we have to do is fiddle the
451 * return pointer so that the ble instruction gets executed again.
453 regs->gr[31] -= 8; /* delayed branching */
455 /* Get assembler opcode of code in delay branch */
456 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
457 err = get_user(opcode, uaddr);
461 /* Check if delay branch uses "ldi int,%r20" */
462 if ((opcode & 0xffff0000) == 0x34140000)
463 return; /* everything ok, just return */
465 /* Check if delay branch uses "nop" */
466 if (opcode == INSN_NOP)
469 /* Check if delay branch uses "copy %rX,%r20" */
470 if ((opcode & 0xffe0ffff) == 0x08000254) {
471 source_reg = (opcode >> 16) & 31;
472 regs->gr[source_reg] = regs->gr[20];
476 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
477 current->comm, task_pid_nr(current), opcode);
481 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
485 regs->orig_r28 = 1; /* no more restarts */
486 /* Check the return code */
487 switch (regs->gr[28]) {
488 case -ERESTART_RESTARTBLOCK:
489 case -ERESTARTNOHAND:
490 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
491 regs->gr[28] = -EINTR;
494 if (!(ka->sa.sa_flags & SA_RESTART)) {
495 DBG(1,"ERESTARTSYS: putting -EINTR\n");
496 regs->gr[28] = -EINTR;
500 case -ERESTARTNOINTR:
501 check_syscallno_in_delay_branch(regs);
507 insert_restart_trampoline(struct pt_regs *regs)
511 regs->orig_r28 = 1; /* no more restarts */
512 switch(regs->gr[28]) {
513 case -ERESTART_RESTARTBLOCK: {
514 /* Restart the system call - no handlers present */
515 unsigned int *usp = (unsigned int *)regs->gr[30];
516 unsigned long start = (unsigned long) &usp[2];
517 unsigned long end = (unsigned long) &usp[5];
520 /* check that we don't exceed the stack */
521 if (A(&usp[0]) >= user_addr_max() - 5 * sizeof(int))
524 /* Setup a trampoline to restart the syscall
525 * with __NR_restart_syscall
527 * 0: <return address (orig r31)>
528 * 4: <2nd half for 64-bit>
529 * 8: ldw 0(%sp), %r31
530 * 12: be 0x100(%sr2, %r0)
531 * 16: ldi __NR_restart_syscall, %r20
534 err |= put_user(regs->gr[31] >> 32, &usp[0]);
535 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
536 err |= put_user(0x0fc010df, &usp[2]);
538 err |= put_user(regs->gr[31], &usp[0]);
539 err |= put_user(0x0fc0109f, &usp[2]);
541 err |= put_user(0xe0008200, &usp[3]);
542 err |= put_user(0x34140000, &usp[4]);
546 /* flush data/instruction cache for new insns */
547 flush_user_dcache_range_asm(start, end);
548 flush_user_icache_range_asm(start, end);
550 regs->gr[31] = regs->gr[30] + 8;
553 case -ERESTARTNOHAND:
555 case -ERESTARTNOINTR:
556 check_syscallno_in_delay_branch(regs);
564 * We need to be able to restore the syscall arguments (r21-r26) to
565 * restart syscalls. Thus, the syscall path should save them in the
566 * pt_regs structure (it's okay to do so since they are caller-save
567 * registers). As noted below, the syscall number gets restored for
568 * us due to the magic of delayed branching.
571 do_signal(struct pt_regs *regs, long in_syscall)
575 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
576 regs, regs->sr[7], in_syscall);
578 if (get_signal(&ksig)) {
579 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
580 /* Restart a system call if necessary. */
582 syscall_restart(regs, &ksig.ka);
584 handle_signal(&ksig, regs, in_syscall);
588 /* Did we come from a system call? */
590 insert_restart_trampoline(regs);
592 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
595 restore_saved_sigmask();
598 void do_notify_resume(struct pt_regs *regs, long in_syscall)
600 if (test_thread_flag(TIF_SIGPENDING) ||
601 test_thread_flag(TIF_NOTIFY_SIGNAL))
602 do_signal(regs, in_syscall);
604 if (test_thread_flag(TIF_NOTIFY_RESUME))
605 tracehook_notify_resume(regs);