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));
241 if (is_compat_task()) {
242 /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
243 usp = (compat_uint_t)usp;
246 /*FIXME: frame_size parameter is unused, remove it. */
247 frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
249 DBG(1,"SETUP_RT_FRAME: START\n");
250 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
255 compat_frame = (struct compat_rt_sigframe __user *)frame;
257 if (is_compat_task()) {
258 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
259 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
260 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
261 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
262 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
263 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
264 &compat_frame->regs, regs, in_syscall);
265 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
266 sizeof(compat_sigset_t));
270 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
271 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
272 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
273 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
274 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
275 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
276 /* FIXME: Should probably be converted as well for the compat case */
277 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
283 /* Set up to return from userspace. If provided, use a stub
284 already in userspace. The first words of tramp are used to
285 save the previous sigrestartblock trampoline that might be
286 on the stack. We start the sigreturn trampoline at
287 SIGRESTARTBLOCK_TRAMP+X. */
288 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
289 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
290 err |= __put_user(INSN_LDI_R20,
291 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
292 err |= __put_user(INSN_BLE_SR2_R0,
293 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
294 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
296 start = (unsigned long) &frame->tramp[0];
297 end = (unsigned long) &frame->tramp[TRAMP_SIZE];
298 flush_user_dcache_range_asm(start, end);
299 flush_user_icache_range_asm(start, end);
301 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
302 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
303 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
305 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
310 haddr = A(ksig->ka.sa.sa_handler);
311 /* The sa_handler may be a pointer to a function descriptor */
313 if (is_compat_task()) {
315 if (haddr & PA_PLABEL_FDESC) {
317 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
319 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
325 regs->gr[19] = fdesc.gp;
330 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
332 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
338 regs->gr[19] = fdesc.gp;
339 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
340 haddr, regs->gr[19], in_syscall);
344 /* The syscall return path will create IAOQ values from r31.
346 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
348 if (is_compat_task())
349 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
352 regs->gr[31] = haddr;
354 if (!test_thread_flag(TIF_32BIT))
358 unsigned long psw = USER_PSW;
360 if (!test_thread_flag(TIF_32BIT))
364 /* If we are singlestepping, arrange a trap to be delivered
365 when we return to userspace. Note the semantics -- we
366 should trap before the first insn in the handler is
368 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
370 if (pa_psw(current)->r) {
371 pa_psw(current)->r = 0;
377 regs->iaoq[0] = haddr | 3;
378 regs->iaoq[1] = regs->iaoq[0] + 4;
381 regs->gr[2] = rp; /* userland return pointer */
382 regs->gr[26] = ksig->sig; /* signal number */
385 if (is_compat_task()) {
386 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
387 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
391 regs->gr[25] = A(&frame->info); /* siginfo pointer */
392 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
395 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
396 regs->gr[30], sigframe_size,
397 regs->gr[30] + sigframe_size);
398 /* Raise the user stack pointer to make a proper call frame. */
399 regs->gr[30] = (A(frame) + sigframe_size);
402 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
403 current->comm, current->pid, frame, regs->gr[30],
404 regs->iaoq[0], regs->iaoq[1], rp);
410 * OK, we're invoking a handler.
414 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
417 sigset_t *oldset = sigmask_to_save();
419 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
420 ksig->sig, ksig->ka, ksig->info, oldset, regs);
422 /* Set up the stack frame */
423 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
425 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
426 test_thread_flag(TIF_BLOCKSTEP));
428 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
433 * Check how the syscall number gets loaded into %r20 within
434 * the delay branch in userspace and adjust as needed.
437 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
439 u32 opcode, source_reg;
443 /* Usually we don't have to restore %r20 (the system call number)
444 * because it gets loaded in the delay slot of the branch external
445 * instruction via the ldi instruction.
446 * In some cases a register-to-register copy instruction might have
447 * been used instead, in which case we need to copy the syscall
448 * number into the source register before returning to userspace.
451 /* A syscall is just a branch, so all we have to do is fiddle the
452 * return pointer so that the ble instruction gets executed again.
454 regs->gr[31] -= 8; /* delayed branching */
456 /* Get assembler opcode of code in delay branch */
457 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
458 err = get_user(opcode, uaddr);
462 /* Check if delay branch uses "ldi int,%r20" */
463 if ((opcode & 0xffff0000) == 0x34140000)
464 return; /* everything ok, just return */
466 /* Check if delay branch uses "nop" */
467 if (opcode == INSN_NOP)
470 /* Check if delay branch uses "copy %rX,%r20" */
471 if ((opcode & 0xffe0ffff) == 0x08000254) {
472 source_reg = (opcode >> 16) & 31;
473 regs->gr[source_reg] = regs->gr[20];
477 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
478 current->comm, task_pid_nr(current), opcode);
482 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
486 regs->orig_r28 = 1; /* no more restarts */
487 /* Check the return code */
488 switch (regs->gr[28]) {
489 case -ERESTART_RESTARTBLOCK:
490 case -ERESTARTNOHAND:
491 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
492 regs->gr[28] = -EINTR;
495 if (!(ka->sa.sa_flags & SA_RESTART)) {
496 DBG(1,"ERESTARTSYS: putting -EINTR\n");
497 regs->gr[28] = -EINTR;
501 case -ERESTARTNOINTR:
502 check_syscallno_in_delay_branch(regs);
508 insert_restart_trampoline(struct pt_regs *regs)
512 regs->orig_r28 = 1; /* no more restarts */
513 switch(regs->gr[28]) {
514 case -ERESTART_RESTARTBLOCK: {
515 /* Restart the system call - no handlers present */
516 unsigned int *usp = (unsigned int *)regs->gr[30];
517 unsigned long start = (unsigned long) &usp[2];
518 unsigned long end = (unsigned long) &usp[5];
521 /* Setup a trampoline to restart the syscall
522 * with __NR_restart_syscall
524 * 0: <return address (orig r31)>
525 * 4: <2nd half for 64-bit>
526 * 8: ldw 0(%sp), %r31
527 * 12: be 0x100(%sr2, %r0)
528 * 16: ldi __NR_restart_syscall, %r20
531 err |= put_user(regs->gr[31] >> 32, &usp[0]);
532 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
533 err |= put_user(0x0fc010df, &usp[2]);
535 err |= put_user(regs->gr[31], &usp[0]);
536 err |= put_user(0x0fc0109f, &usp[2]);
538 err |= put_user(0xe0008200, &usp[3]);
539 err |= put_user(0x34140000, &usp[4]);
543 /* flush data/instruction cache for new insns */
544 flush_user_dcache_range_asm(start, end);
545 flush_user_icache_range_asm(start, end);
547 regs->gr[31] = regs->gr[30] + 8;
550 case -ERESTARTNOHAND:
552 case -ERESTARTNOINTR:
553 check_syscallno_in_delay_branch(regs);
561 * We need to be able to restore the syscall arguments (r21-r26) to
562 * restart syscalls. Thus, the syscall path should save them in the
563 * pt_regs structure (it's okay to do so since they are caller-save
564 * registers). As noted below, the syscall number gets restored for
565 * us due to the magic of delayed branching.
568 do_signal(struct pt_regs *regs, long in_syscall)
572 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
573 regs, regs->sr[7], in_syscall);
575 if (get_signal(&ksig)) {
576 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
577 /* Restart a system call if necessary. */
579 syscall_restart(regs, &ksig.ka);
581 handle_signal(&ksig, regs, in_syscall);
585 /* Did we come from a system call? */
587 insert_restart_trampoline(regs);
589 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
592 restore_saved_sigmask();
595 void do_notify_resume(struct pt_regs *regs, long in_syscall)
597 if (test_thread_flag(TIF_SIGPENDING) ||
598 test_thread_flag(TIF_NOTIFY_SIGNAL))
599 do_signal(regs, in_syscall);
601 if (test_thread_flag(TIF_NOTIFY_RESUME))
602 tracehook_notify_resume(regs);