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 */
68 #define INSN_NOP 0x08000240 /* nop */
70 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
73 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
77 err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
78 err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
79 err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
80 err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
81 err |= __get_user(regs->sar, &sc->sc_sar);
82 DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
83 regs->iaoq[0],regs->iaoq[1]);
84 DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
89 sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
91 struct rt_sigframe __user *frame;
93 unsigned long usp = (regs->gr[30] & ~(0x01UL));
94 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
96 compat_sigset_t compat_set;
97 struct compat_rt_sigframe __user * compat_frame;
100 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
103 current->restart_block.fn = do_no_restart_syscall;
105 /* Unwind the user stack to get the rt_sigframe structure. */
106 frame = (struct rt_sigframe __user *)
107 (usp - sigframe_size);
108 DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
110 regs->orig_r28 = 1; /* no restarts for sigreturn */
113 compat_frame = (struct compat_rt_sigframe __user *)frame;
115 if (is_compat_task()) {
116 DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
117 if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set)))
119 sigset_32to64(&set,&compat_set);
123 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
127 set_current_blocked(&set);
129 /* Good thing we saved the old gr[30], eh? */
131 if (is_compat_task()) {
132 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
133 &compat_frame->uc.uc_mcontext);
134 // FIXME: Load upper half from register file
135 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
136 &compat_frame->regs, regs))
138 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
139 usp, &compat_frame->uc.uc_stack);
140 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
145 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
146 &frame->uc.uc_mcontext);
147 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
149 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
150 usp, &frame->uc.uc_stack);
151 if (restore_altstack(&frame->uc.uc_stack))
157 /* If we are on the syscall path IAOQ will not be restored, and
158 * if we are on the interrupt path we must not corrupt gr31.
161 regs->gr[31] = regs->iaoq[0];
163 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
169 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
170 force_sig(SIGSEGV, current);
175 * Set up a signal frame.
178 static inline void __user *
179 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
181 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
182 don't use the parameter it doesn't matter */
184 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
185 (unsigned long)ka, sp, frame_size);
187 /* Align alternate stack and reserve 64 bytes for the signal
188 handler's frame marker. */
189 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
190 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
192 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
193 return (void __user *) sp; /* Stacks grow up. Fun. */
197 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
200 unsigned long flags = 0;
203 if (on_sig_stack((unsigned long) sc))
204 flags |= PARISC_SC_FLAG_ONSTACK;
206 flags |= PARISC_SC_FLAG_IN_SYSCALL;
207 /* regs->iaoq is undefined in the syscall return path */
208 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
209 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
210 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
211 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
212 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
213 regs->gr[31], regs->gr[31]+4);
215 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
216 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
217 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n",
218 regs->iaoq[0], regs->iaoq[1]);
221 err |= __put_user(flags, &sc->sc_flags);
222 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
223 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
224 err |= __put_user(regs->sar, &sc->sc_sar);
225 DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
231 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
234 struct rt_sigframe __user *frame;
235 unsigned long rp, usp;
236 unsigned long haddr, sigframe_size;
237 unsigned long start, end;
240 struct compat_rt_sigframe __user * compat_frame;
241 compat_sigset_t compat_set;
244 usp = (regs->gr[30] & ~(0x01UL));
246 if (is_compat_task()) {
247 /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
248 usp = (compat_uint_t)usp;
251 /*FIXME: frame_size parameter is unused, remove it. */
252 frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
254 DBG(1,"SETUP_RT_FRAME: START\n");
255 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
260 compat_frame = (struct compat_rt_sigframe __user *)frame;
262 if (is_compat_task()) {
263 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
264 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
265 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
266 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
267 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
268 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
269 &compat_frame->regs, regs, in_syscall);
270 sigset_64to32(&compat_set,set);
271 err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set));
275 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
276 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
277 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
278 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
279 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
280 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
281 /* FIXME: Should probably be converted as well for the compat case */
282 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
288 /* Set up to return from userspace. If provided, use a stub
289 already in userspace. The first words of tramp are used to
290 save the previous sigrestartblock trampoline that might be
291 on the stack. We start the sigreturn trampoline at
292 SIGRESTARTBLOCK_TRAMP+X. */
293 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
294 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
295 err |= __put_user(INSN_LDI_R20,
296 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
297 err |= __put_user(INSN_BLE_SR2_R0,
298 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
299 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
302 /* Assert that we're flushing in the correct space... */
305 asm ("mfsp %%sr3,%0" : "=r" (sid));
306 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
311 start = (unsigned long) &frame->tramp[0];
312 end = (unsigned long) &frame->tramp[TRAMP_SIZE];
313 flush_user_dcache_range_asm(start, end);
314 flush_user_icache_range_asm(start, end);
316 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
317 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
318 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
320 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
325 haddr = A(ksig->ka.sa.sa_handler);
326 /* The sa_handler may be a pointer to a function descriptor */
328 if (is_compat_task()) {
330 if (haddr & PA_PLABEL_FDESC) {
332 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
334 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
340 regs->gr[19] = fdesc.gp;
345 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
347 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
353 regs->gr[19] = fdesc.gp;
354 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
355 haddr, regs->gr[19], in_syscall);
359 /* The syscall return path will create IAOQ values from r31.
361 sigframe_size = PARISC_RT_SIGFRAME_SIZE;
363 if (is_compat_task())
364 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
367 regs->gr[31] = haddr;
369 if (!test_thread_flag(TIF_32BIT))
373 unsigned long psw = USER_PSW;
375 if (!test_thread_flag(TIF_32BIT))
379 /* If we are singlestepping, arrange a trap to be delivered
380 when we return to userspace. Note the semantics -- we
381 should trap before the first insn in the handler is
383 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
385 if (pa_psw(current)->r) {
386 pa_psw(current)->r = 0;
392 regs->iaoq[0] = haddr | 3;
393 regs->iaoq[1] = regs->iaoq[0] + 4;
396 regs->gr[2] = rp; /* userland return pointer */
397 regs->gr[26] = ksig->sig; /* signal number */
400 if (is_compat_task()) {
401 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
402 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
406 regs->gr[25] = A(&frame->info); /* siginfo pointer */
407 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
410 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
411 regs->gr[30], sigframe_size,
412 regs->gr[30] + sigframe_size);
413 /* Raise the user stack pointer to make a proper call frame. */
414 regs->gr[30] = (A(frame) + sigframe_size);
417 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
418 current->comm, current->pid, frame, regs->gr[30],
419 regs->iaoq[0], regs->iaoq[1], rp);
425 * OK, we're invoking a handler.
429 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
432 sigset_t *oldset = sigmask_to_save();
434 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
435 ksig->sig, ksig->ka, ksig->info, oldset, regs);
437 /* Set up the stack frame */
438 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
440 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
441 test_thread_flag(TIF_BLOCKSTEP));
443 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
448 * Check how the syscall number gets loaded into %r20 within
449 * the delay branch in userspace and adjust as needed.
452 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
454 u32 opcode, source_reg;
458 /* Usually we don't have to restore %r20 (the system call number)
459 * because it gets loaded in the delay slot of the branch external
460 * instruction via the ldi instruction.
461 * In some cases a register-to-register copy instruction might have
462 * been used instead, in which case we need to copy the syscall
463 * number into the source register before returning to userspace.
466 /* A syscall is just a branch, so all we have to do is fiddle the
467 * return pointer so that the ble instruction gets executed again.
469 regs->gr[31] -= 8; /* delayed branching */
471 /* Get assembler opcode of code in delay branch */
472 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
473 err = get_user(opcode, uaddr);
477 /* Check if delay branch uses "ldi int,%r20" */
478 if ((opcode & 0xffff0000) == 0x34140000)
479 return; /* everything ok, just return */
481 /* Check if delay branch uses "nop" */
482 if (opcode == INSN_NOP)
485 /* Check if delay branch uses "copy %rX,%r20" */
486 if ((opcode & 0xffe0ffff) == 0x08000254) {
487 source_reg = (opcode >> 16) & 31;
488 regs->gr[source_reg] = regs->gr[20];
492 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
493 current->comm, task_pid_nr(current), opcode);
497 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
501 regs->orig_r28 = 1; /* no more restarts */
502 /* Check the return code */
503 switch (regs->gr[28]) {
504 case -ERESTART_RESTARTBLOCK:
505 case -ERESTARTNOHAND:
506 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
507 regs->gr[28] = -EINTR;
511 if (!(ka->sa.sa_flags & SA_RESTART)) {
512 DBG(1,"ERESTARTSYS: putting -EINTR\n");
513 regs->gr[28] = -EINTR;
517 case -ERESTARTNOINTR:
518 check_syscallno_in_delay_branch(regs);
524 insert_restart_trampoline(struct pt_regs *regs)
528 regs->orig_r28 = 1; /* no more restarts */
529 switch(regs->gr[28]) {
530 case -ERESTART_RESTARTBLOCK: {
531 /* Restart the system call - no handlers present */
532 unsigned int *usp = (unsigned int *)regs->gr[30];
533 unsigned long start = (unsigned long) &usp[2];
534 unsigned long end = (unsigned long) &usp[5];
537 /* Setup a trampoline to restart the syscall
538 * with __NR_restart_syscall
540 * 0: <return address (orig r31)>
541 * 4: <2nd half for 64-bit>
542 * 8: ldw 0(%sp), %r31
543 * 12: be 0x100(%sr2, %r0)
544 * 16: ldi __NR_restart_syscall, %r20
547 err |= put_user(regs->gr[31] >> 32, &usp[0]);
548 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
549 err |= put_user(0x0fc010df, &usp[2]);
551 err |= put_user(regs->gr[31], &usp[0]);
552 err |= put_user(0x0fc0109f, &usp[2]);
554 err |= put_user(0xe0008200, &usp[3]);
555 err |= put_user(0x34140000, &usp[4]);
559 /* flush data/instruction cache for new insns */
560 flush_user_dcache_range_asm(start, end);
561 flush_user_icache_range_asm(start, end);
563 regs->gr[31] = regs->gr[30] + 8;
566 case -ERESTARTNOHAND:
568 case -ERESTARTNOINTR:
569 check_syscallno_in_delay_branch(regs);
577 * Note that 'init' is a special process: it doesn't get signals it doesn't
578 * want to handle. Thus you cannot kill init even with a SIGKILL even by
581 * We need to be able to restore the syscall arguments (r21-r26) to
582 * restart syscalls. Thus, the syscall path should save them in the
583 * pt_regs structure (it's okay to do so since they are caller-save
584 * registers). As noted below, the syscall number gets restored for
585 * us due to the magic of delayed branching.
588 do_signal(struct pt_regs *regs, long in_syscall)
592 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
593 regs, regs->sr[7], in_syscall);
595 if (get_signal(&ksig)) {
596 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
597 /* Restart a system call if necessary. */
599 syscall_restart(regs, &ksig.ka);
601 handle_signal(&ksig, regs, in_syscall);
605 /* Did we come from a system call? */
607 insert_restart_trampoline(regs);
609 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
612 restore_saved_sigmask();
615 void do_notify_resume(struct pt_regs *regs, long in_syscall)
617 if (test_thread_flag(TIF_SIGPENDING))
618 do_signal(regs, in_syscall);
620 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
621 clear_thread_flag(TIF_NOTIFY_RESUME);
622 tracehook_notify_resume(regs);