/* * linux/arch/sh/kernel/signal.c * * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima * */ #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/ptrace.h> #include <linux/unistd.h> #include <linux/stddef.h> #include <linux/tty.h> #include <linux/elf.h> #include <linux/personality.h> #include <linux/binfmts.h> #include <linux/freezer.h> #include <linux/io.h> #include <linux/tracehook.h> #include <asm/system.h> #include <asm/ucontext.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/cacheflush.h> #include <asm/syscalls.h> #include <asm/fpu.h> #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) struct fdpic_func_descriptor { unsigned long text; unsigned long GOT; }; /* * The following define adds a 64 byte gap between the signal * stack frame and previous contents of the stack. This allows * frame unwinding in a function epilogue but only if a frame * pointer is used in the function. This is necessary because * current gcc compilers (<4.3) do not generate unwind info on * SH for function epilogues. */ #define UNWINDGUARD 64 /* * Atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int sys_sigsuspend(old_sigset_t mask, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { mask &= _BLOCKABLE; spin_lock_irq(¤t->sighand->siglock); current->saved_sigmask = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); current->state = TASK_INTERRUPTIBLE; schedule(); set_restore_sigmask(); return -ERESTARTNOHAND; } asmlinkage int sys_sigaction(int sig, const struct old_sigaction __user *act, struct old_sigaction __user *oact) { struct k_sigaction new_ka, old_ka; int ret; if (act) { old_sigset_t mask; if (!access_ok(VERIFY_READ, act, sizeof(*act)) || __get_user(new_ka.sa.sa_handler, &act->sa_handler) || __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) return -EFAULT; __get_user(new_ka.sa.sa_flags, &act->sa_flags); __get_user(mask, &act->sa_mask); siginitset(&new_ka.sa.sa_mask, mask); } ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) return -EFAULT; __put_user(old_ka.sa.sa_flags, &oact->sa_flags); __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); } return ret; } asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); return do_sigaltstack(uss, uoss, regs->regs[15]); } /* * Do a signal return; undo the signal stack. */ #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ #if defined(CONFIG_CPU_SH2) #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ #else #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ #endif #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ struct sigframe { struct sigcontext sc; unsigned long extramask[_NSIG_WORDS-1]; u16 retcode[8]; }; struct rt_sigframe { struct siginfo info; struct ucontext uc; u16 retcode[8]; }; #ifdef CONFIG_SH_FPU static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) { struct task_struct *tsk = current; if (!(boot_cpu_data.flags & CPU_HAS_FPU)) return 0; set_used_math(); return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0], sizeof(long)*(16*2+2)); } static inline int save_sigcontext_fpu(struct sigcontext __user *sc, struct pt_regs *regs) { struct task_struct *tsk = current; if (!(boot_cpu_data.flags & CPU_HAS_FPU)) return 0; if (!used_math()) { __put_user(0, &sc->sc_ownedfp); return 0; } __put_user(1, &sc->sc_ownedfp); /* This will cause a "finit" to be triggered by the next attempted FPU operation by the 'current' process. */ clear_used_math(); unlazy_fpu(tsk, regs); return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard, sizeof(long)*(16*2+2)); } #endif /* CONFIG_SH_FPU */ static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) { unsigned int err = 0; #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) COPY(regs[1]); COPY(regs[2]); COPY(regs[3]); COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]); COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]); COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]); COPY(gbr); COPY(mach); COPY(macl); COPY(pr); COPY(sr); COPY(pc); #undef COPY #ifdef CONFIG_SH_FPU if (boot_cpu_data.flags & CPU_HAS_FPU) { int owned_fp; struct task_struct *tsk = current; regs->sr |= SR_FD; /* Release FPU */ clear_fpu(tsk, regs); clear_used_math(); __get_user (owned_fp, &sc->sc_ownedfp); if (owned_fp) err |= restore_sigcontext_fpu(sc); } #endif regs->tra = -1; /* disable syscall checks */ err |= __get_user(*r0_p, &sc->sc_regs[0]); return err; } asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; sigset_t set; int r0; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); if (restore_sigcontext(regs, &frame->sc, &r0)) goto badframe; return r0; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, struct pt_regs __regs) { struct pt_regs *regs = RELOC_HIDE(&__regs, 0); struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; sigset_t set; int r0; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) goto badframe; if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->regs[15]) == -EFAULT) goto badframe; return r0; badframe: force_sig(SIGSEGV, current); return 0; } /* * Set up a signal frame. */ static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask) { int err = 0; #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]); COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]); COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]); COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]); COPY(gbr); COPY(mach); COPY(macl); COPY(pr); COPY(sr); COPY(pc); #undef COPY #ifdef CONFIG_SH_FPU err |= save_sigcontext_fpu(sc, regs); #endif /* non-iBCS2 extensions.. */ err |= __put_user(mask, &sc->oldmask); return err; } /* * Determine which stack to use.. */ static inline void __user * get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) { if (ka->sa.sa_flags & SA_ONSTACK) { if (sas_ss_flags(sp) == 0) sp = current->sas_ss_sp + current->sas_ss_size; } return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); } /* These symbols are defined with the addresses in the vsyscall page. See vsyscall-trapa.S. */ extern void __kernel_sigreturn(void); extern void __kernel_rt_sigreturn(void); static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) { struct sigframe __user *frame; int err = 0; int signal; frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; signal = current_thread_info()->exec_domain && current_thread_info()->exec_domain->signal_invmap && sig < 32 ? current_thread_info()->exec_domain->signal_invmap[sig] : sig; err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); if (_NSIG_WORDS > 1) err |= __copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask)); /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { regs->pr = (unsigned long) ka->sa.sa_restorer; #ifdef CONFIG_VSYSCALL } else if (likely(current->mm->context.vdso)) { regs->pr = VDSO_SYM(&__kernel_sigreturn); #endif } else { /* Generate return code (system call to sigreturn) */ err |= __put_user(MOVW(7), &frame->retcode[0]); err |= __put_user(TRAP_NOARG, &frame->retcode[1]); err |= __put_user(OR_R0_R0, &frame->retcode[2]); err |= __put_user(OR_R0_R0, &frame->retcode[3]); err |= __put_user(OR_R0_R0, &frame->retcode[4]); err |= __put_user(OR_R0_R0, &frame->retcode[5]); err |= __put_user(OR_R0_R0, &frame->retcode[6]); err |= __put_user((__NR_sigreturn), &frame->retcode[7]); regs->pr = (unsigned long) frame->retcode; flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ regs->regs[15] = (unsigned long) frame; regs->regs[4] = signal; /* Arg for signal handler */ regs->regs[5] = 0; regs->regs[6] = (unsigned long) &frame->sc; if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; __get_user(regs->pc, &funcptr->text); __get_user(regs->regs[12], &funcptr->GOT); } else regs->pc = (unsigned long)ka->sa.sa_handler; set_fs(USER_DS); pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); return 0; give_sigsegv: force_sigsegv(sig, current); return -EFAULT; } static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *frame; int err = 0; int signal; frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; signal = current_thread_info()->exec_domain && current_thread_info()->exec_domain->signal_invmap && sig < 32 ? current_thread_info()->exec_domain->signal_invmap[sig] : sig; err |= copy_siginfo_to_user(&frame->info, info); /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(NULL, &frame->uc.uc_link); err |= __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(regs->regs[15]), &frame->uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { regs->pr = (unsigned long) ka->sa.sa_restorer; #ifdef CONFIG_VSYSCALL } else if (likely(current->mm->context.vdso)) { regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); #endif } else { /* Generate return code (system call to rt_sigreturn) */ err |= __put_user(MOVW(7), &frame->retcode[0]); err |= __put_user(TRAP_NOARG, &frame->retcode[1]); err |= __put_user(OR_R0_R0, &frame->retcode[2]); err |= __put_user(OR_R0_R0, &frame->retcode[3]); err |= __put_user(OR_R0_R0, &frame->retcode[4]); err |= __put_user(OR_R0_R0, &frame->retcode[5]); err |= __put_user(OR_R0_R0, &frame->retcode[6]); err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); regs->pr = (unsigned long) frame->retcode; flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ regs->regs[15] = (unsigned long) frame; regs->regs[4] = signal; /* Arg for signal handler */ regs->regs[5] = (unsigned long) &frame->info; regs->regs[6] = (unsigned long) &frame->uc; if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; __get_user(regs->pc, &funcptr->text); __get_user(regs->regs[12], &funcptr->GOT); } else regs->pc = (unsigned long)ka->sa.sa_handler; set_fs(USER_DS); pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); return 0; give_sigsegv: force_sigsegv(sig, current); return -EFAULT; } static inline void handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, struct sigaction *sa) { /* If we're not from a syscall, bail out */ if (regs->tra < 0) return; /* check for system call restart.. */ switch (regs->regs[0]) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: no_system_call_restart: regs->regs[0] = -EINTR; break; case -ERESTARTSYS: if (!(sa->sa_flags & SA_RESTART)) goto no_system_call_restart; /* fallthrough */ case -ERESTARTNOINTR: regs->regs[0] = save_r0; regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); break; } } /* * OK, we're invoking a handler */ static int handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0) { int ret; /* Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) ret = setup_rt_frame(sig, ka, info, oldset, regs); else ret = setup_frame(sig, ka, oldset, regs); if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (ret == 0) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); if (!(ka->sa.sa_flags & SA_NODEFER)) sigaddset(¤t->blocked,sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } return ret; } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. * * Note that we go through the signals twice: once to check the signals that * the kernel can handle, and then we build all the user-level signal handling * stack-frames in one go after that. */ static void do_signal(struct pt_regs *regs, unsigned int save_r0) { siginfo_t info; int signr; struct k_sigaction ka; sigset_t *oldset; /* * We want the common case to go fast, which * is why we may in certain cases get here from * kernel mode. Just return without doing anything * if so. */ if (!user_mode(regs)) return; if (try_to_freeze()) goto no_signal; if (current_thread_info()->status & TS_RESTORE_SIGMASK) oldset = ¤t->saved_sigmask; else oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, &ka, regs, NULL); if (signr > 0) { handle_syscall_restart(save_r0, regs, &ka.sa); /* Whee! Actually deliver the signal. */ if (handle_signal(signr, &ka, &info, oldset, regs, save_r0) == 0) { /* * A signal was successfully delivered; the saved * sigmask will have been stored in the signal frame, * and will be restored by sigreturn, so we can simply * clear the TS_RESTORE_SIGMASK flag */ current_thread_info()->status &= ~TS_RESTORE_SIGMASK; tracehook_signal_handler(signr, &info, &ka, regs, test_thread_flag(TIF_SINGLESTEP)); } return; } no_signal: /* Did we come from a system call? */ if (regs->tra >= 0) { /* Restart the system call - no handlers present */ if (regs->regs[0] == -ERESTARTNOHAND || regs->regs[0] == -ERESTARTSYS || regs->regs[0] == -ERESTARTNOINTR) { regs->regs[0] = save_r0; regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); regs->regs[3] = __NR_restart_syscall; } } /* * If there's no signal to deliver, we just put the saved sigmask * back. */ if (current_thread_info()->status & TS_RESTORE_SIGMASK) { current_thread_info()->status &= ~TS_RESTORE_SIGMASK; sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); } } asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, unsigned long thread_info_flags) { /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs, save_r0); if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); if (current->replacement_session_keyring) key_replace_session_keyring(); } }