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. */
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_BLE_SR2_R0,
295 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
296 err |= __put_user(INSN_LDI_R20,
297 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
299 start = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+0];
300 end = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+3];
301 flush_user_dcache_range_asm(start, end);
302 flush_user_icache_range_asm(start, end);
304 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
305 * TRAMP Words 5-7, Length 3 = SIGRETURN_TRAMP
306 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
308 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
313 haddr = A(ksig->ka.sa.sa_handler);
314 /* The sa_handler may be a pointer to a function descriptor */
316 if (is_compat_task()) {
318 if (haddr & PA_PLABEL_FDESC) {
320 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
322 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
328 regs->gr[19] = fdesc.gp;
333 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
335 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
341 regs->gr[19] = fdesc.gp;
342 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
343 haddr, regs->gr[19], in_syscall);
347 /* The syscall return path will create IAOQ values from r31.
350 regs->gr[31] = haddr;
352 if (!test_thread_flag(TIF_32BIT))
356 unsigned long psw = USER_PSW;
358 if (!test_thread_flag(TIF_32BIT))
362 /* If we are singlestepping, arrange a trap to be delivered
363 when we return to userspace. Note the semantics -- we
364 should trap before the first insn in the handler is
366 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
368 if (pa_psw(current)->r) {
369 pa_psw(current)->r = 0;
375 regs->iaoq[0] = haddr | 3;
376 regs->iaoq[1] = regs->iaoq[0] + 4;
379 regs->gr[2] = rp; /* userland return pointer */
380 regs->gr[26] = ksig->sig; /* signal number */
383 if (is_compat_task()) {
384 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
385 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */
389 regs->gr[25] = A(&frame->info); /* siginfo pointer */
390 regs->gr[24] = A(&frame->uc); /* ucontext pointer */
393 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
394 regs->gr[30], sigframe_size,
395 regs->gr[30] + sigframe_size);
396 /* Raise the user stack pointer to make a proper call frame. */
397 regs->gr[30] = (A(frame) + sigframe_size);
400 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
401 current->comm, current->pid, frame, regs->gr[30],
402 regs->iaoq[0], regs->iaoq[1], rp);
408 * OK, we're invoking a handler.
412 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
415 sigset_t *oldset = sigmask_to_save();
417 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
418 ksig->sig, ksig->ka, ksig->info, oldset, regs);
420 /* Set up the stack frame */
421 ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
423 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
424 test_thread_flag(TIF_BLOCKSTEP));
426 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
431 * Check how the syscall number gets loaded into %r20 within
432 * the delay branch in userspace and adjust as needed.
435 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
437 u32 opcode, source_reg;
441 /* Usually we don't have to restore %r20 (the system call number)
442 * because it gets loaded in the delay slot of the branch external
443 * instruction via the ldi instruction.
444 * In some cases a register-to-register copy instruction might have
445 * been used instead, in which case we need to copy the syscall
446 * number into the source register before returning to userspace.
449 /* A syscall is just a branch, so all we have to do is fiddle the
450 * return pointer so that the ble instruction gets executed again.
452 regs->gr[31] -= 8; /* delayed branching */
454 /* Get assembler opcode of code in delay branch */
455 uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
456 err = get_user(opcode, uaddr);
460 /* Check if delay branch uses "ldi int,%r20" */
461 if ((opcode & 0xffff0000) == 0x34140000)
462 return; /* everything ok, just return */
464 /* Check if delay branch uses "nop" */
465 if (opcode == INSN_NOP)
468 /* Check if delay branch uses "copy %rX,%r20" */
469 if ((opcode & 0xffe0ffff) == 0x08000254) {
470 source_reg = (opcode >> 16) & 31;
471 regs->gr[source_reg] = regs->gr[20];
475 pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
476 current->comm, task_pid_nr(current), opcode);
480 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
484 regs->orig_r28 = 1; /* no more restarts */
485 /* Check the return code */
486 switch (regs->gr[28]) {
487 case -ERESTART_RESTARTBLOCK:
488 case -ERESTARTNOHAND:
489 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
490 regs->gr[28] = -EINTR;
493 if (!(ka->sa.sa_flags & SA_RESTART)) {
494 DBG(1,"ERESTARTSYS: putting -EINTR\n");
495 regs->gr[28] = -EINTR;
499 case -ERESTARTNOINTR:
500 check_syscallno_in_delay_branch(regs);
506 insert_restart_trampoline(struct pt_regs *regs)
510 regs->orig_r28 = 1; /* no more restarts */
511 switch(regs->gr[28]) {
512 case -ERESTART_RESTARTBLOCK: {
513 /* Restart the system call - no handlers present */
514 unsigned int *usp = (unsigned int *)regs->gr[30];
515 unsigned long start = (unsigned long) &usp[2];
516 unsigned long end = (unsigned long) &usp[5];
519 /* check that we don't exceed the stack */
520 if (A(&usp[0]) >= user_addr_max() - 5 * sizeof(int))
523 /* Setup a trampoline to restart the syscall
524 * with __NR_restart_syscall
526 * 0: <return address (orig r31)>
527 * 4: <2nd half for 64-bit>
528 * 8: ldw 0(%sp), %r31
529 * 12: be 0x100(%sr2, %r0)
530 * 16: ldi __NR_restart_syscall, %r20
533 err |= put_user(regs->gr[31] >> 32, &usp[0]);
534 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
535 err |= put_user(0x0fc010df, &usp[2]);
537 err |= put_user(regs->gr[31], &usp[0]);
538 err |= put_user(0x0fc0109f, &usp[2]);
540 err |= put_user(0xe0008200, &usp[3]);
541 err |= put_user(0x34140000, &usp[4]);
545 /* flush data/instruction cache for new insns */
546 flush_user_dcache_range_asm(start, end);
547 flush_user_icache_range_asm(start, end);
549 regs->gr[31] = regs->gr[30] + 8;
552 case -ERESTARTNOHAND:
554 case -ERESTARTNOINTR:
555 check_syscallno_in_delay_branch(regs);
563 * We need to be able to restore the syscall arguments (r21-r26) to
564 * restart syscalls. Thus, the syscall path should save them in the
565 * pt_regs structure (it's okay to do so since they are caller-save
566 * registers). As noted below, the syscall number gets restored for
567 * us due to the magic of delayed branching.
570 do_signal(struct pt_regs *regs, long in_syscall)
574 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
575 regs, regs->sr[7], in_syscall);
577 if (get_signal(&ksig)) {
578 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
579 /* Restart a system call if necessary. */
581 syscall_restart(regs, &ksig.ka);
583 handle_signal(&ksig, regs, in_syscall);
587 /* Did we come from a system call? */
589 insert_restart_trampoline(regs);
591 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
594 restore_saved_sigmask();
597 void do_notify_resume(struct pt_regs *regs, long in_syscall)
599 if (test_thread_flag(TIF_SIGPENDING) ||
600 test_thread_flag(TIF_NOTIFY_SIGNAL))
601 do_signal(regs, in_syscall);
603 if (test_thread_flag(TIF_NOTIFY_RESUME))
604 tracehook_notify_resume(regs);