/* * arch/s390/kernel/signal.c * * S390 version * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) * * Based on Intel version * * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson */ #include <linux/config.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/smp_lock.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/personality.h> #include <linux/binfmts.h> #include <asm/ucontext.h> #include <asm/uaccess.h> #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) typedef struct { __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; struct sigcontext sc; _sigregs sregs; __u8 retcode[S390_SYSCALL_SIZE]; } sigframe; typedef struct { __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; __u8 retcode[S390_SYSCALL_SIZE]; struct siginfo info; struct ucontext uc; } rt_sigframe; int do_signal(struct pt_regs *regs, sigset_t *oldset); /* * Atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int sys_sigsuspend(struct pt_regs * regs, int history0, int history1, old_sigset_t mask) { sigset_t saveset; mask &= _BLOCKABLE; spin_lock_irq(¤t->sighand->siglock); saveset = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); regs->gprs[2] = -EINTR; while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); if (do_signal(regs, &saveset)) return -EINTR; } } asmlinkage int sys_rt_sigsuspend(struct pt_regs * regs,sigset_t *unewset, size_t sigsetsize) { sigset_t saveset, newset; /* XXX: Don't preclude handling different sized sigset_t's. */ if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&newset, unewset, sizeof(newset))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); saveset = current->blocked; current->blocked = newset; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); regs->gprs[2] = -EINTR; while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); if (do_signal(regs, &saveset)) return -EINTR; } } asmlinkage int sys_sigaction(int sig, const struct old_sigaction *act, struct old_sigaction *oact) { struct k_sigaction new_ka, old_ka; int ret; if (act) { old_sigset_t mask; if (verify_area(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 (verify_area(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 *uss, stack_t *uoss, struct pt_regs *regs) { return do_sigaltstack(uss, uoss, regs->gprs[15]); } /* Returns non-zero on fault. */ static int save_sigregs(struct pt_regs *regs,_sigregs *sregs) { int err; err = __copy_to_user(&sregs->regs, regs, sizeof(_s390_regs_common)); if (err != 0) return err; /* * We have to store the fp registers to current->thread.fp_regs * to merge them with the emulated registers. */ save_fp_regs(¤t->thread.fp_regs); return __copy_to_user(&sregs->fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); } /* Returns positive number on error */ static int restore_sigregs(struct pt_regs *regs,_sigregs *sregs) { int err; err = __copy_from_user(regs, &sregs->regs, sizeof(_s390_regs_common)); regs->psw.mask = PSW_USER_BITS | (regs->psw.mask & PSW_MASK_CC); regs->psw.addr |= PSW_ADDR_AMODE31; if (err) return err; err = __copy_from_user(¤t->thread.fp_regs, &sregs->fpregs, sizeof(s390_fp_regs)); current->thread.fp_regs.fpc &= FPC_VALID_MASK; if (err) return err; restore_fp_regs(¤t->thread.fp_regs); regs->trap = -1; /* disable syscall checks */ return 0; } asmlinkage long sys_sigreturn(struct pt_regs *regs) { sigframe *frame = (sigframe *)regs->gprs[15]; sigset_t set; if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE)) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); if (restore_sigregs(regs, &frame->sregs)) goto badframe; return regs->gprs[2]; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) { rt_sigframe *frame = (rt_sigframe *)regs->gprs[15]; sigset_t set; if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set.sig, &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_sigregs(regs, &frame->uc.uc_mcontext)) goto badframe; /* It is more difficult to avoid calling this function than to call it and ignore errors. */ do_sigaltstack(&frame->uc.uc_stack, NULL, regs->gprs[15]); return regs->gprs[2]; badframe: force_sig(SIGSEGV, current); return 0; } /* * Set up a signal frame. */ /* * Determine which stack to use.. */ static inline void * get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) { unsigned long sp; /* Default to using normal stack */ sp = regs->gprs[15]; /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { if (! on_sig_stack(sp)) sp = current->sas_ss_sp + current->sas_ss_size; } /* This is the legacy signal stack switching. */ else if (!user_mode(regs) && !(ka->sa.sa_flags & SA_RESTORER) && ka->sa.sa_restorer) { sp = (unsigned long) ka->sa.sa_restorer; } return (void *)((sp - frame_size) & -8ul); } static inline int map_signal(int sig) { if (current_thread_info()->exec_domain && current_thread_info()->exec_domain->signal_invmap && sig < 32) return current_thread_info()->exec_domain->signal_invmap[sig]; else return sig; } static void setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs) { sigframe *frame = get_sigframe(ka, regs, sizeof(sigframe)); if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe))) goto give_sigsegv; if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE)) goto give_sigsegv; if (save_sigregs(regs, &frame->sregs)) goto give_sigsegv; if (__put_user(&frame->sregs, &frame->sc.sregs)) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { regs->gprs[14] = (__u32) ka->sa.sa_restorer | PSW_ADDR_AMODE31; } else { regs->gprs[14] = (__u32) frame->retcode | PSW_ADDR_AMODE31; if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, (u16 *)(frame->retcode))) goto give_sigsegv; } /* Set up backchain. */ if (__put_user(regs->gprs[15], (addr_t *) frame)) goto give_sigsegv; /* Set up registers for signal handler */ regs->gprs[15] = (__u32) frame; regs->psw.addr = (__u32) ka->sa.sa_handler | PSW_ADDR_AMODE31; regs->psw.mask = PSW_USER_BITS; regs->gprs[2] = map_signal(sig); regs->gprs[3] = (__u32) &frame->sc; /* We forgot to include these in the sigcontext. To avoid breaking binary compatibility, they are passed as args. */ regs->gprs[4] = current->thread.trap_no; regs->gprs[5] = current->thread.prot_addr; return; give_sigsegv: if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs) { int err = 0; rt_sigframe *frame = get_sigframe(ka, regs, sizeof(rt_sigframe)); if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe))) goto give_sigsegv; if (copy_siginfo_to_user(&frame->info, info)) goto give_sigsegv; /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &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->gprs[15]), &frame->uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= save_sigregs(regs, &frame->uc.uc_mcontext); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { regs->gprs[14] = (__u32) ka->sa.sa_restorer | PSW_ADDR_AMODE31; } else { regs->gprs[14] = (__u32) frame->retcode | PSW_ADDR_AMODE31; err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, (u16 *)(frame->retcode)); } /* Set up backchain. */ if (__put_user(regs->gprs[15], (addr_t *) frame)) goto give_sigsegv; /* Set up registers for signal handler */ regs->gprs[15] = (__u32) frame; regs->psw.addr = (__u32) ka->sa.sa_handler | PSW_ADDR_AMODE31; regs->psw.mask = PSW_USER_BITS; regs->gprs[2] = map_signal(sig); regs->gprs[3] = (__u32) &frame->info; regs->gprs[4] = (__u32) &frame->uc; return; give_sigsegv: if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } /* * OK, we're invoking a handler */ static void handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) { struct k_sigaction *ka = ¤t->sig->action[sig-1]; /* Are we from a system call? */ if (regs->trap == __LC_SVC_OLD_PSW) { /* If so, check system call restarting.. */ switch (regs->gprs[2]) { case -ERESTART_RESTARTBLOCK: current_thread_info()->restart_block.fn = do_no_restart_syscall; clear_thread_flag(TIF_RESTART_SVC); case -ERESTARTNOHAND: regs->gprs[2] = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->gprs[2] = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: regs->gprs[2] = regs->orig_gpr2; regs->psw.addr -= 2; } } /* Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) setup_rt_frame(sig, ka, info, oldset, regs); else setup_frame(sig, ka, oldset, regs); if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (!(ka->sa.sa_flags & SA_NODEFER)) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); sigaddset(¤t->blocked,sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } } /* * 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. */ int do_signal(struct pt_regs *regs, sigset_t *oldset) { siginfo_t info; int signr; /* * 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 1; if (!oldset) oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, regs, NULL); if (signr > 0) { /* Whee! Actually deliver the signal. */ handle_signal(signr, &info, oldset, regs); return 1; } /* Did we come from a system call? */ if ( regs->trap == __LC_SVC_OLD_PSW /* System Call! */ ) { /* Restart the system call - no handlers present */ if (regs->gprs[2] == -ERESTARTNOHAND || regs->gprs[2] == -ERESTARTSYS || regs->gprs[2] == -ERESTARTNOINTR) { regs->gprs[2] = regs->orig_gpr2; regs->psw.addr -= 2; } /* Restart the system call with a new system call number */ if (regs->gprs[2] == -ERESTART_RESTARTBLOCK) { regs->gprs[2] = __NR_restart_syscall; set_thread_flag(TIF_RESTART_SVC); } } return 0; }