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/pgalloc.h>
34 #include <asm/cacheflush.h>
35 #include <asm/asm-offsets.h>
42 #define DEBUG_SIG_LEVEL 2
45 #define DBG(LEVEL, ...) \
46 ((DEBUG_SIG_LEVEL >= LEVEL) \
47 ? printk(__VA_ARGS__) : (void) 0)
49 #define DBG(LEVEL, ...)
52 /* gcc will complain if a pointer is cast to an integer of different
53 * size. If you really need to do this (and we do for an ELF32 user
54 * application in an ELF64 kernel) then you have to do a cast to an
55 * integer of the same size first. The A() macro accomplishes
57 #define A(__x) ((unsigned long)(__x))
60 * Do a signal return - restore sigcontext.
63 /* Trampoline for calling rt_sigreturn() */
64 #define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */
65 #define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */
66 #define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */
67 #define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
69 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
72 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
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]);
88 sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
90 struct rt_sigframe __user *frame;
92 unsigned long usp = (regs->gr[30] & ~(0x01UL));
93 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
95 struct compat_rt_sigframe __user * compat_frame;
98 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
101 current->restart_block.fn = do_no_restart_syscall;
103 /* Unwind the user stack to get the rt_sigframe structure. */
104 frame = (struct rt_sigframe __user *)
105 (usp - sigframe_size);
106 DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
108 regs->orig_r28 = 1; /* no restarts for sigreturn */
111 compat_frame = (struct compat_rt_sigframe __user *)frame;
113 if (is_compat_task()) {
114 DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
115 if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
120 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
124 set_current_blocked(&set);
126 /* Good thing we saved the old gr[30], eh? */
128 if (is_compat_task()) {
129 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
130 &compat_frame->uc.uc_mcontext);
131 // FIXME: Load upper half from register file
132 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
133 &compat_frame->regs, regs))
135 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
136 usp, &compat_frame->uc.uc_stack);
137 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
142 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
143 &frame->uc.uc_mcontext);
144 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
146 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
147 usp, &frame->uc.uc_stack);
148 if (restore_altstack(&frame->uc.uc_stack))
154 /* If we are on the syscall path IAOQ will not be restored, and
155 * if we are on the interrupt path we must not corrupt gr31.
158 regs->gr[31] = regs->iaoq[0];
160 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
166 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
172 * Set up a signal frame.
175 static inline void __user *
176 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
178 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
179 don't use the parameter it doesn't matter */
181 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
182 (unsigned long)ka, sp, frame_size);
184 /* Align alternate stack and reserve 64 bytes for the signal
185 handler's frame marker. */
186 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
187 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
189 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
190 return (void __user *) sp; /* Stacks grow up. Fun. */
194 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
197 unsigned long flags = 0;
200 if (on_sig_stack((unsigned long) sc))
201 flags |= PARISC_SC_FLAG_ONSTACK;
203 flags |= PARISC_SC_FLAG_IN_SYSCALL;
204 /* regs->iaoq is undefined in the syscall return path */
205 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
206 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
207 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
208 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
209 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
210 regs->gr[31], regs->gr[31]+4);
212 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
213 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
214 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n",
215 regs->iaoq[0], regs->iaoq[1]);
218 err |= __put_user(flags, &sc->sc_flags);
219 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
220 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
221 err |= __put_user(regs->sar, &sc->sc_sar);
222 DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
228 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
231 struct rt_sigframe __user *frame;
232 unsigned long rp, usp;
233 unsigned long haddr, sigframe_size;
234 unsigned long start, end;
237 struct compat_rt_sigframe __user * compat_frame;
240 usp = (regs->gr[30] & ~(0x01UL));
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;
247 /*FIXME: frame_size parameter is unused, remove it. */
248 frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
250 DBG(1,"SETUP_RT_FRAME: START\n");
251 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
256 compat_frame = (struct compat_rt_sigframe __user *)frame;
258 if (is_compat_task()) {
259 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
260 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
261 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
262 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
263 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
264 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
265 &compat_frame->regs, regs, in_syscall);
266 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
267 sizeof(compat_sigset_t));
271 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
272 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
273 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
274 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
275 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
276 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
277 /* FIXME: Should probably be converted as well for the compat case */
278 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
284 /* Set up to return from userspace. If provided, use a stub
285 already in userspace. The first words of tramp are used to
286 save the previous sigrestartblock trampoline that might be
287 on the stack. We start the sigreturn trampoline at
288 SIGRESTARTBLOCK_TRAMP+X. */
289 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
290 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
291 err |= __put_user(INSN_LDI_R20,
292 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
293 err |= __put_user(INSN_BLE_SR2_R0,
294 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
295 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
298 /* Assert that we're flushing in the correct space... */
301 asm ("mfsp %%sr3,%0" : "=r" (sid));
302 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
307 start = (unsigned long) &frame->tramp[0];
308 end = (unsigned long) &frame->tramp[TRAMP_SIZE];
309 flush_user_dcache_range_asm(start, end);
310 flush_user_icache_range_asm(start, end);
312 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
313 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
314 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
316 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
321 haddr = A(ksig->ka.sa.sa_handler);
322 /* The sa_handler may be a pointer to a function descriptor */
324 if (is_compat_task()) {
326 if (haddr & PA_PLABEL_FDESC) {
328 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
330 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
336 regs->gr[19] = fdesc.gp;
341 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
343 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
349 regs->gr[19] = fdesc.gp;
350 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
351 haddr, regs->gr[19], in_syscall);
355 /* The syscall return path will create IAOQ values from r31.
357 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
359 if (is_compat_task())
360 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
363 regs->gr[31] = haddr;
365 if (!test_thread_flag(TIF_32BIT))
369 unsigned long psw = USER_PSW;
371 if (!test_thread_flag(TIF_32BIT))
375 /* If we are singlestepping, arrange a trap to be delivered
376 when we return to userspace. Note the semantics -- we
377 should trap before the first insn in the handler is
379 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
381 if (pa_psw(current)->r) {
382 pa_psw(current)->r = 0;
388 regs->iaoq[0] = haddr | 3;
389 regs->iaoq[1] = regs->iaoq[0] + 4;
392 regs->gr[2] = rp; /* userland return pointer */
393 regs->gr[26] = ksig->sig; /* signal number */
396 if (is_compat_task()) {
397 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
398 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
402 regs->gr[25] = A(&frame->info); /* siginfo pointer */
403 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
406 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
407 regs->gr[30], sigframe_size,
408 regs->gr[30] + sigframe_size);
409 /* Raise the user stack pointer to make a proper call frame. */
410 regs->gr[30] = (A(frame) + sigframe_size);
413 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
414 current->comm, current->pid, frame, regs->gr[30],
415 regs->iaoq[0], regs->iaoq[1], rp);
421 * OK, we're invoking a handler.
425 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
428 sigset_t *oldset = sigmask_to_save();
430 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
431 ksig->sig, ksig->ka, ksig->info, oldset, regs);
433 /* Set up the stack frame */
434 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
436 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
437 test_thread_flag(TIF_BLOCKSTEP));
439 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
444 * Check how the syscall number gets loaded into %r20 within
445 * the delay branch in userspace and adjust as needed.
448 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
450 u32 opcode, source_reg;
454 /* Usually we don't have to restore %r20 (the system call number)
455 * because it gets loaded in the delay slot of the branch external
456 * instruction via the ldi instruction.
457 * In some cases a register-to-register copy instruction might have
458 * been used instead, in which case we need to copy the syscall
459 * number into the source register before returning to userspace.
462 /* A syscall is just a branch, so all we have to do is fiddle the
463 * return pointer so that the ble instruction gets executed again.
465 regs->gr[31] -= 8; /* delayed branching */
467 /* Get assembler opcode of code in delay branch */
468 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
469 err = get_user(opcode, uaddr);
473 /* Check if delay branch uses "ldi int,%r20" */
474 if ((opcode & 0xffff0000) == 0x34140000)
475 return; /* everything ok, just return */
477 /* Check if delay branch uses "nop" */
478 if (opcode == INSN_NOP)
481 /* Check if delay branch uses "copy %rX,%r20" */
482 if ((opcode & 0xffe0ffff) == 0x08000254) {
483 source_reg = (opcode >> 16) & 31;
484 regs->gr[source_reg] = regs->gr[20];
488 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
489 current->comm, task_pid_nr(current), opcode);
493 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
497 regs->orig_r28 = 1; /* no more restarts */
498 /* Check the return code */
499 switch (regs->gr[28]) {
500 case -ERESTART_RESTARTBLOCK:
501 case -ERESTARTNOHAND:
502 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
503 regs->gr[28] = -EINTR;
507 if (!(ka->sa.sa_flags & SA_RESTART)) {
508 DBG(1,"ERESTARTSYS: putting -EINTR\n");
509 regs->gr[28] = -EINTR;
513 case -ERESTARTNOINTR:
514 check_syscallno_in_delay_branch(regs);
520 insert_restart_trampoline(struct pt_regs *regs)
524 regs->orig_r28 = 1; /* no more restarts */
525 switch(regs->gr[28]) {
526 case -ERESTART_RESTARTBLOCK: {
527 /* Restart the system call - no handlers present */
528 unsigned int *usp = (unsigned int *)regs->gr[30];
529 unsigned long start = (unsigned long) &usp[2];
530 unsigned long end = (unsigned long) &usp[5];
533 /* Setup a trampoline to restart the syscall
534 * with __NR_restart_syscall
536 * 0: <return address (orig r31)>
537 * 4: <2nd half for 64-bit>
538 * 8: ldw 0(%sp), %r31
539 * 12: be 0x100(%sr2, %r0)
540 * 16: ldi __NR_restart_syscall, %r20
543 err |= put_user(regs->gr[31] >> 32, &usp[0]);
544 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
545 err |= put_user(0x0fc010df, &usp[2]);
547 err |= put_user(regs->gr[31], &usp[0]);
548 err |= put_user(0x0fc0109f, &usp[2]);
550 err |= put_user(0xe0008200, &usp[3]);
551 err |= put_user(0x34140000, &usp[4]);
555 /* flush data/instruction cache for new insns */
556 flush_user_dcache_range_asm(start, end);
557 flush_user_icache_range_asm(start, end);
559 regs->gr[31] = regs->gr[30] + 8;
562 case -ERESTARTNOHAND:
564 case -ERESTARTNOINTR:
565 check_syscallno_in_delay_branch(regs);
573 * Note that 'init' is a special process: it doesn't get signals it doesn't
574 * want to handle. Thus you cannot kill init even with a SIGKILL even by
577 * We need to be able to restore the syscall arguments (r21-r26) to
578 * restart syscalls. Thus, the syscall path should save them in the
579 * pt_regs structure (it's okay to do so since they are caller-save
580 * registers). As noted below, the syscall number gets restored for
581 * us due to the magic of delayed branching.
584 do_signal(struct pt_regs *regs, long in_syscall)
588 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
589 regs, regs->sr[7], in_syscall);
591 if (get_signal(&ksig)) {
592 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
593 /* Restart a system call if necessary. */
595 syscall_restart(regs, &ksig.ka);
597 handle_signal(&ksig, regs, in_syscall);
601 /* Did we come from a system call? */
603 insert_restart_trampoline(regs);
605 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
608 restore_saved_sigmask();
611 void do_notify_resume(struct pt_regs *regs, long in_syscall)
613 if (test_thread_flag(TIF_SIGPENDING))
614 do_signal(regs, in_syscall);
616 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
617 clear_thread_flag(TIF_NOTIFY_RESUME);
618 tracehook_notify_resume(regs);