2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1991, 1992 Linus Torvalds
7 * Copyright (C) 1994 - 2000 Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2014, Imagination Technologies Ltd.
11 #include <linux/cache.h>
12 #include <linux/context_tracking.h>
13 #include <linux/irqflags.h>
14 #include <linux/sched.h>
16 #include <linux/personality.h>
17 #include <linux/smp.h>
18 #include <linux/kernel.h>
19 #include <linux/signal.h>
20 #include <linux/errno.h>
21 #include <linux/wait.h>
22 #include <linux/ptrace.h>
23 #include <linux/unistd.h>
24 #include <linux/uprobes.h>
25 #include <linux/compiler.h>
26 #include <linux/syscalls.h>
27 #include <linux/uaccess.h>
28 #include <linux/tracehook.h>
32 #include <linux/bitops.h>
33 #include <asm/cacheflush.h>
36 #include <asm/ucontext.h>
37 #include <asm/cpu-features.h>
43 #include "signal-common.h"
45 static int (*save_fp_context)(void __user *sc);
46 static int (*restore_fp_context)(void __user *sc);
49 u32 sf_ass[4]; /* argument save space for o32 */
50 u32 sf_pad[2]; /* Was: signal trampoline */
52 /* Matches struct ucontext from its uc_mcontext field onwards */
53 struct sigcontext sf_sc;
55 unsigned long long sf_extcontext[0];
59 u32 rs_ass[4]; /* argument save space for o32 */
60 u32 rs_pad[2]; /* Was: signal trampoline */
61 struct siginfo rs_info;
62 struct ucontext rs_uc;
66 * Thread saved context copy to/from a signal context presumed to be on the
67 * user stack, and therefore accessed with appropriate macros from uaccess.h.
69 static int copy_fp_to_sigcontext(void __user *sc)
71 struct mips_abi *abi = current->thread.abi;
72 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
73 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
76 int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
78 for (i = 0; i < NUM_FPU_REGS; i += inc) {
80 __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0),
83 err |= __put_user(current->thread.fpu.fcr31, csr);
88 static int copy_fp_from_sigcontext(void __user *sc)
90 struct mips_abi *abi = current->thread.abi;
91 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
92 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
95 int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
98 for (i = 0; i < NUM_FPU_REGS; i += inc) {
99 err |= __get_user(fpr_val, &fpregs[i]);
100 set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val);
102 err |= __get_user(current->thread.fpu.fcr31, csr);
108 * Wrappers for the assembly _{save,restore}_fp_context functions.
110 static int save_hw_fp_context(void __user *sc)
112 struct mips_abi *abi = current->thread.abi;
113 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
114 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
116 return _save_fp_context(fpregs, csr);
119 static int restore_hw_fp_context(void __user *sc)
121 struct mips_abi *abi = current->thread.abi;
122 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
123 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
125 return _restore_fp_context(fpregs, csr);
129 * Extended context handling.
132 static inline void __user *sc_to_extcontext(void __user *sc)
134 struct ucontext __user *uc;
137 * We can just pretend the sigcontext is always embedded in a struct
138 * ucontext here, because the offset from sigcontext to extended
139 * context is the same in the struct sigframe case.
141 uc = container_of(sc, struct ucontext, uc_mcontext);
142 return &uc->uc_extcontext;
145 static int save_msa_extcontext(void __user *buf)
147 struct msa_extcontext __user *msa = buf;
151 if (!thread_msa_context_live())
155 * Ensure that we can't lose the live MSA context between checking
156 * for it & writing it to memory.
160 if (is_msa_enabled()) {
162 * There are no EVA versions of the vector register load/store
163 * instructions, so MSA context has to be saved to kernel memory
164 * and then copied to user memory. The save to kernel memory
165 * should already have been done when handling scalar FP
168 BUG_ON(IS_ENABLED(CONFIG_EVA));
170 err = __put_user(read_msa_csr(), &msa->csr);
171 err |= _save_msa_all_upper(&msa->wr);
177 err = __put_user(current->thread.fpu.msacsr, &msa->csr);
179 for (i = 0; i < NUM_FPU_REGS; i++) {
180 val = get_fpr64(¤t->thread.fpu.fpr[i], 1);
181 err |= __put_user(val, &msa->wr[i]);
185 err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);
186 err |= __put_user(sizeof(*msa), &msa->ext.size);
188 return err ? -EFAULT : sizeof(*msa);
191 static int restore_msa_extcontext(void __user *buf, unsigned int size)
193 struct msa_extcontext __user *msa = buf;
194 unsigned long long val;
198 if (!IS_ENABLED(CONFIG_CPU_HAS_MSA))
201 if (size != sizeof(*msa))
204 err = get_user(csr, &msa->csr);
210 if (is_msa_enabled()) {
212 * There are no EVA versions of the vector register load/store
213 * instructions, so MSA context has to be copied to kernel
214 * memory and later loaded to registers. The same is true of
215 * scalar FP context, so FPU & MSA should have already been
216 * disabled whilst handling scalar FP context.
218 BUG_ON(IS_ENABLED(CONFIG_EVA));
221 err |= _restore_msa_all_upper(&msa->wr);
226 current->thread.fpu.msacsr = csr;
228 for (i = 0; i < NUM_FPU_REGS; i++) {
229 err |= __get_user(val, &msa->wr[i]);
230 set_fpr64(¤t->thread.fpu.fpr[i], 1, val);
237 static int save_extcontext(void __user *buf)
241 sz = save_msa_extcontext(buf);
246 /* If no context was saved then trivially return */
250 /* Write the end marker */
251 if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))
254 sz += sizeof(((struct extcontext *)NULL)->magic);
258 static int restore_extcontext(void __user *buf)
260 struct extcontext ext;
264 err = __get_user(ext.magic, (unsigned int *)buf);
268 if (ext.magic == END_EXTCONTEXT_MAGIC)
271 err = __get_user(ext.size, (unsigned int *)(buf
272 + offsetof(struct extcontext, size)));
277 case MSA_EXTCONTEXT_MAGIC:
278 err = restore_msa_extcontext(buf, ext.size);
296 int protected_save_fp_context(void __user *sc)
298 struct mips_abi *abi = current->thread.abi;
299 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
300 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
301 uint32_t __user *used_math = sc + abi->off_sc_used_math;
302 unsigned int used, ext_sz;
305 used = used_math() ? USED_FP : 0;
309 if (!test_thread_flag(TIF_32BIT_FPREGS))
311 if (test_thread_flag(TIF_HYBRID_FPREGS))
312 used |= USED_HYBRID_FPRS;
315 * EVA does not have userland equivalents of ldc1 or sdc1, so
316 * save to the kernel FP context & copy that to userland below.
318 if (IS_ENABLED(CONFIG_EVA))
323 if (is_fpu_owner()) {
324 err = save_fp_context(sc);
328 err = copy_fp_to_sigcontext(sc);
332 /* touch the sigcontext and try again */
333 err = __put_user(0, &fpregs[0]) |
334 __put_user(0, &fpregs[31]) |
337 return err; /* really bad sigcontext */
341 ext_sz = err = save_extcontext(sc_to_extcontext(sc));
344 used |= ext_sz ? USED_EXTCONTEXT : 0;
346 return __put_user(used, used_math);
349 int protected_restore_fp_context(void __user *sc)
351 struct mips_abi *abi = current->thread.abi;
352 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
353 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
354 uint32_t __user *used_math = sc + abi->off_sc_used_math;
356 int err, sig = 0, tmp __maybe_unused;
358 err = __get_user(used, used_math);
359 conditional_used_math(used & USED_FP);
362 * The signal handler may have used FPU; give it up if the program
363 * doesn't want it following sigreturn.
365 if (err || !(used & USED_FP))
369 if (!(used & USED_FP))
372 err = sig = fpcsr_pending(csr);
377 * EVA does not have userland equivalents of ldc1 or sdc1, so we
378 * disable the FPU here such that the code below simply copies to
379 * the kernel FP context.
381 if (IS_ENABLED(CONFIG_EVA))
386 if (is_fpu_owner()) {
387 err = restore_fp_context(sc);
391 err = copy_fp_from_sigcontext(sc);
395 /* touch the sigcontext and try again */
396 err = __get_user(tmp, &fpregs[0]) |
397 __get_user(tmp, &fpregs[31]) |
398 __get_user(tmp, csr);
400 break; /* really bad sigcontext */
404 if (!err && (used & USED_EXTCONTEXT))
405 err = restore_extcontext(sc_to_extcontext(sc));
410 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
415 err |= __put_user(regs->cp0_epc, &sc->sc_pc);
417 err |= __put_user(0, &sc->sc_regs[0]);
418 for (i = 1; i < 32; i++)
419 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
421 #ifdef CONFIG_CPU_HAS_SMARTMIPS
422 err |= __put_user(regs->acx, &sc->sc_acx);
424 err |= __put_user(regs->hi, &sc->sc_mdhi);
425 err |= __put_user(regs->lo, &sc->sc_mdlo);
427 err |= __put_user(mfhi1(), &sc->sc_hi1);
428 err |= __put_user(mflo1(), &sc->sc_lo1);
429 err |= __put_user(mfhi2(), &sc->sc_hi2);
430 err |= __put_user(mflo2(), &sc->sc_lo2);
431 err |= __put_user(mfhi3(), &sc->sc_hi3);
432 err |= __put_user(mflo3(), &sc->sc_lo3);
433 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
438 * Save FPU state to signal context. Signal handler
439 * will "inherit" current FPU state.
441 err |= protected_save_fp_context(sc);
446 static size_t extcontext_max_size(void)
451 * The assumption here is that between this point & the point at which
452 * the extended context is saved the size of the context should only
453 * ever be able to shrink (if the task is preempted), but never grow.
454 * That is, what this function returns is an upper bound on the size of
455 * the extended context for the current task at the current time.
458 if (thread_msa_context_live())
459 sz += sizeof(struct msa_extcontext);
461 /* If any context is saved then we'll append the end marker */
463 sz += sizeof(((struct extcontext *)NULL)->magic);
468 int fpcsr_pending(unsigned int __user *fpcsr)
471 unsigned int csr, enabled;
473 err = __get_user(csr, fpcsr);
474 enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
476 * If the signal handler set some FPU exceptions, clear it and
481 err |= __put_user(csr, fpcsr);
487 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
493 /* Always make any pending restarted system calls return -EINTR */
494 current->restart_block.fn = do_no_restart_syscall;
496 err |= __get_user(regs->cp0_epc, &sc->sc_pc);
498 #ifdef CONFIG_CPU_HAS_SMARTMIPS
499 err |= __get_user(regs->acx, &sc->sc_acx);
501 err |= __get_user(regs->hi, &sc->sc_mdhi);
502 err |= __get_user(regs->lo, &sc->sc_mdlo);
504 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
505 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
506 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
507 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
508 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
509 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
510 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
513 for (i = 1; i < 32; i++)
514 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
516 return err ?: protected_restore_fp_context(sc);
519 void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
524 /* Leave space for potential extended context */
525 frame_size += extcontext_max_size();
527 /* Default to using normal stack */
531 * FPU emulator may have it's own trampoline active just
532 * above the user stack, 16-bytes before the next lowest
533 * 16 byte boundary. Try to avoid trashing it.
537 sp = sigsp(sp, ksig);
539 return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
543 * Atomically swap in the new signal mask, and wait for a signal.
546 #ifdef CONFIG_TRAD_SIGNALS
547 SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
549 return sys_rt_sigsuspend(uset, sizeof(sigset_t));
553 #ifdef CONFIG_TRAD_SIGNALS
554 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
555 struct sigaction __user *, oact)
557 struct k_sigaction new_ka, old_ka;
564 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
566 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
567 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
568 err |= __get_user(mask, &act->sa_mask.sig[0]);
572 siginitset(&new_ka.sa.sa_mask, mask);
575 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
578 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
580 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
581 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
582 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
583 err |= __put_user(0, &oact->sa_mask.sig[1]);
584 err |= __put_user(0, &oact->sa_mask.sig[2]);
585 err |= __put_user(0, &oact->sa_mask.sig[3]);
594 #ifdef CONFIG_TRAD_SIGNALS
595 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
597 struct sigframe __user *frame;
601 frame = (struct sigframe __user *) regs.regs[29];
602 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
604 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
607 set_current_blocked(&blocked);
609 sig = restore_sigcontext(®s, &frame->sf_sc);
613 force_sig(sig, current);
616 * Don't let your children do this ...
618 __asm__ __volatile__(
626 force_sig(SIGSEGV, current);
628 #endif /* CONFIG_TRAD_SIGNALS */
630 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
632 struct rt_sigframe __user *frame;
636 frame = (struct rt_sigframe __user *) regs.regs[29];
637 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
639 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
642 set_current_blocked(&set);
644 sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext);
648 force_sig(sig, current);
650 if (restore_altstack(&frame->rs_uc.uc_stack))
654 * Don't let your children do this ...
656 __asm__ __volatile__(
664 force_sig(SIGSEGV, current);
667 #ifdef CONFIG_TRAD_SIGNALS
668 static int setup_frame(void *sig_return, struct ksignal *ksig,
669 struct pt_regs *regs, sigset_t *set)
671 struct sigframe __user *frame;
674 frame = get_sigframe(ksig, regs, sizeof(*frame));
675 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
678 err |= setup_sigcontext(regs, &frame->sf_sc);
679 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
684 * Arguments to signal handler:
687 * a1 = 0 (should be cause)
688 * a2 = pointer to struct sigcontext
690 * $25 and c0_epc point to the signal handler, $29 points to the
693 regs->regs[ 4] = ksig->sig;
695 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
696 regs->regs[29] = (unsigned long) frame;
697 regs->regs[31] = (unsigned long) sig_return;
698 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
700 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
701 current->comm, current->pid,
702 frame, regs->cp0_epc, regs->regs[31]);
707 static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
708 struct pt_regs *regs, sigset_t *set)
710 struct rt_sigframe __user *frame;
713 frame = get_sigframe(ksig, regs, sizeof(*frame));
714 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
717 /* Create siginfo. */
718 err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
720 /* Create the ucontext. */
721 err |= __put_user(0, &frame->rs_uc.uc_flags);
722 err |= __put_user(NULL, &frame->rs_uc.uc_link);
723 err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
724 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
725 err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
731 * Arguments to signal handler:
734 * a1 = 0 (should be cause)
735 * a2 = pointer to ucontext
737 * $25 and c0_epc point to the signal handler, $29 points to
738 * the struct rt_sigframe.
740 regs->regs[ 4] = ksig->sig;
741 regs->regs[ 5] = (unsigned long) &frame->rs_info;
742 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
743 regs->regs[29] = (unsigned long) frame;
744 regs->regs[31] = (unsigned long) sig_return;
745 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
747 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
748 current->comm, current->pid,
749 frame, regs->cp0_epc, regs->regs[31]);
754 struct mips_abi mips_abi = {
755 #ifdef CONFIG_TRAD_SIGNALS
756 .setup_frame = setup_frame,
758 .setup_rt_frame = setup_rt_frame,
759 .restart = __NR_restart_syscall,
761 .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
762 .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
763 .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
768 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
770 sigset_t *oldset = sigmask_to_save();
772 struct mips_abi *abi = current->thread.abi;
773 void *vdso = current->mm->context.vdso;
776 * If we were emulating a delay slot instruction, exit that frame such
777 * that addresses in the sigframe are as expected for userland and we
778 * don't have a problem if we reuse the thread's frame for an
779 * instruction within the signal handler.
781 dsemul_thread_rollback(regs);
784 switch(regs->regs[2]) {
785 case ERESTART_RESTARTBLOCK:
787 regs->regs[2] = EINTR;
790 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
791 regs->regs[2] = EINTR;
796 regs->regs[7] = regs->regs[26];
797 regs->regs[2] = regs->regs[0];
801 regs->regs[0] = 0; /* Don't deal with this again. */
804 if (sig_uses_siginfo(&ksig->ka, abi))
805 ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
808 ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn,
811 signal_setup_done(ret, ksig, 0);
814 static void do_signal(struct pt_regs *regs)
818 if (get_signal(&ksig)) {
819 /* Whee! Actually deliver the signal. */
820 handle_signal(&ksig, regs);
825 switch (regs->regs[2]) {
829 regs->regs[2] = regs->regs[0];
830 regs->regs[7] = regs->regs[26];
834 case ERESTART_RESTARTBLOCK:
835 regs->regs[2] = current->thread.abi->restart;
836 regs->regs[7] = regs->regs[26];
840 regs->regs[0] = 0; /* Don't deal with this again. */
844 * If there's no signal to deliver, we just put the saved sigmask
847 restore_saved_sigmask();
851 * notification of userspace execution resumption
852 * - triggered by the TIF_WORK_MASK flags
854 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
855 __u32 thread_info_flags)
861 if (thread_info_flags & _TIF_UPROBE)
862 uprobe_notify_resume(regs);
864 /* deal with pending signal delivery */
865 if (thread_info_flags & _TIF_SIGPENDING)
868 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
869 clear_thread_flag(TIF_NOTIFY_RESUME);
870 tracehook_notify_resume(regs);
877 static int smp_save_fp_context(void __user *sc)
879 return raw_cpu_has_fpu
880 ? save_hw_fp_context(sc)
881 : copy_fp_to_sigcontext(sc);
884 static int smp_restore_fp_context(void __user *sc)
886 return raw_cpu_has_fpu
887 ? restore_hw_fp_context(sc)
888 : copy_fp_from_sigcontext(sc);
892 static int signal_setup(void)
895 * The offset from sigcontext to extended context should be the same
896 * regardless of the type of signal, such that userland can always know
897 * where to look if it wishes to find the extended context structures.
899 BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
900 offsetof(struct sigframe, sf_sc)) !=
901 (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
902 offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
905 /* For now just do the cpu_has_fpu check when the functions are invoked */
906 save_fp_context = smp_save_fp_context;
907 restore_fp_context = smp_restore_fp_context;
910 save_fp_context = save_hw_fp_context;
911 restore_fp_context = restore_hw_fp_context;
913 save_fp_context = copy_fp_to_sigcontext;
914 restore_fp_context = copy_fp_from_sigcontext;
916 #endif /* CONFIG_SMP */
921 arch_initcall(signal_setup);