/* * linux/arch/arm/kernel/signal.c * * Copyright (C) 1995-2001 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ptrace.h" #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) /* * For ARM syscalls, we encode the syscall number into the instruction. */ #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)) #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)) /* * For Thumb syscalls, we pass the syscall number via r7. We therefore * need two 16-bit instructions. */ #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) static const unsigned long retcodes[4] = { SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN }; asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from) { int err = -EFAULT;; if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) goto out; if (from->si_code < 0) return __copy_to_user(to, from, sizeof(siginfo_t)); /* If you change siginfo_t structure, please be sure this code is fixed accordingly. It should never copy any pad contained in the structure to avoid security leaks, but must copy the generic 3 ints plus the relevant union member. */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); err |= __put_user((short)from->si_code, &to->si_code); /* First 32bits of unions are always present. */ err |= __put_user(from->si_pid, &to->si_pid); switch (from->si_code >> 16) { case __SI_FAULT >> 16: break; case __SI_CHLD >> 16: err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); err |= __put_user(from->si_status, &to->si_status); default: err |= __put_user(from->si_uid, &to->si_uid); break; /* case __SI_RT: This is not generated by the kernel as of now. */ } out: return err; } /* * atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs) { sigset_t saveset; mask &= _BLOCKABLE; spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->ARM_r0 = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(&saveset, regs, 0)) return regs->ARM_r0; } } asmlinkage int sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, struct pt_regs *regs) { 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->sigmask_lock); saveset = current->blocked; current->blocked = newset; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->ARM_r0 = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(&saveset, regs, 0)) return regs->ARM_r0; } } 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; } /* * Do a signal return; undo the signal stack. */ struct sigframe { struct sigcontext sc; unsigned long extramask[_NSIG_WORDS-1]; unsigned long retcode; }; struct rt_sigframe { struct siginfo *pinfo; void *puc; struct siginfo info; struct ucontext uc; unsigned long retcode; }; static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc) { int err = 0; __get_user_error(regs->ARM_r0, &sc->arm_r0, err); __get_user_error(regs->ARM_r1, &sc->arm_r1, err); __get_user_error(regs->ARM_r2, &sc->arm_r2, err); __get_user_error(regs->ARM_r3, &sc->arm_r3, err); __get_user_error(regs->ARM_r4, &sc->arm_r4, err); __get_user_error(regs->ARM_r5, &sc->arm_r5, err); __get_user_error(regs->ARM_r6, &sc->arm_r6, err); __get_user_error(regs->ARM_r7, &sc->arm_r7, err); __get_user_error(regs->ARM_r8, &sc->arm_r8, err); __get_user_error(regs->ARM_r9, &sc->arm_r9, err); __get_user_error(regs->ARM_r10, &sc->arm_r10, err); __get_user_error(regs->ARM_fp, &sc->arm_fp, err); __get_user_error(regs->ARM_ip, &sc->arm_ip, err); __get_user_error(regs->ARM_sp, &sc->arm_sp, err); __get_user_error(regs->ARM_lr, &sc->arm_lr, err); __get_user_error(regs->ARM_pc, &sc->arm_pc, err); #ifdef CONFIG_CPU_32 __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err); #endif err |= !valid_user_regs(regs); return err; } asmlinkage int sys_sigreturn(struct pt_regs *regs) { struct sigframe *frame; sigset_t set; /* * Since we stacked the signal on a 64-bit boundary, * then 'sp' should be word aligned here. If it's * not, then the user is trying to mess with us. */ if (regs->ARM_sp & 7) goto badframe; frame = (struct sigframe *)regs->ARM_sp; if (verify_area(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->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(regs, &frame->sc)) goto badframe; /* Send SIGTRAP if we're single-stepping */ if (ptrace_cancel_bpt(current)) send_sig(SIGTRAP, current, 1); return regs->ARM_r0; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe *frame; sigset_t set; /* * Since we stacked the signal on a 64-bit boundary, * then 'sp' should be word aligned here. If it's * not, then the user is trying to mess with us. */ if (regs->ARM_sp & 7) goto badframe; frame = (struct rt_sigframe *)regs->ARM_sp; if (verify_area(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->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; /* Send SIGTRAP if we're single-stepping */ if (ptrace_cancel_bpt(current)) send_sig(SIGTRAP, current, 1); return regs->ARM_r0; badframe: force_sig(SIGSEGV, current); return 0; } static int setup_sigcontext(struct sigcontext *sc, /*struct _fpstate *fpstate,*/ struct pt_regs *regs, unsigned long mask) { int err = 0; __put_user_error(regs->ARM_r0, &sc->arm_r0, err); __put_user_error(regs->ARM_r1, &sc->arm_r1, err); __put_user_error(regs->ARM_r2, &sc->arm_r2, err); __put_user_error(regs->ARM_r3, &sc->arm_r3, err); __put_user_error(regs->ARM_r4, &sc->arm_r4, err); __put_user_error(regs->ARM_r5, &sc->arm_r5, err); __put_user_error(regs->ARM_r6, &sc->arm_r6, err); __put_user_error(regs->ARM_r7, &sc->arm_r7, err); __put_user_error(regs->ARM_r8, &sc->arm_r8, err); __put_user_error(regs->ARM_r9, &sc->arm_r9, err); __put_user_error(regs->ARM_r10, &sc->arm_r10, err); __put_user_error(regs->ARM_fp, &sc->arm_fp, err); __put_user_error(regs->ARM_ip, &sc->arm_ip, err); __put_user_error(regs->ARM_sp, &sc->arm_sp, err); __put_user_error(regs->ARM_lr, &sc->arm_lr, err); __put_user_error(regs->ARM_pc, &sc->arm_pc, err); #ifdef CONFIG_CPU_32 __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err); #endif __put_user_error(current->thread.trap_no, &sc->trap_no, err); __put_user_error(current->thread.error_code, &sc->error_code, err); __put_user_error(current->thread.address, &sc->fault_address, err); __put_user_error(mask, &sc->oldmask, err); return err; } static inline void * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) { unsigned long sp = regs->ARM_sp; /* * This is the X/Open sanctioned signal stack switching. */ if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp)) sp = current->sas_ss_sp + current->sas_ss_size; /* * ATPCS B01 mandates 8-byte alignment */ return (void *)((sp - framesize) & ~7); } static int setup_return(struct pt_regs *regs, struct k_sigaction *ka, unsigned long *rc, void *frame, int usig) { unsigned long handler = (unsigned long)ka->sa.sa_handler; unsigned long retcode; int thumb = 0; #ifdef CONFIG_CPU_32 unsigned long cpsr = regs->ARM_cpsr; /* * Maybe we need to deliver a 32-bit signal to a 26-bit task. */ if (ka->sa.sa_flags & SA_THIRTYTWO) cpsr = (cpsr & ~MODE_MASK) | USR_MODE; #ifdef CONFIG_ARM_THUMB if (elf_hwcap & HWCAP_THUMB) { /* * The LSB of the handler determines if we're going to * be using THUMB or ARM mode for this signal handler. */ thumb = handler & 1; if (thumb) cpsr |= T_BIT; else cpsr &= ~T_BIT; } #endif #endif if (ka->sa.sa_flags & SA_RESTORER) { retcode = (unsigned long)ka->sa.sa_restorer; } else { unsigned int idx = thumb; if (ka->sa.sa_flags & SA_SIGINFO) idx += 2; if (__put_user(retcodes[idx], rc)) return 1; flush_icache_range((unsigned long)rc, (unsigned long)(rc + 1)); retcode = ((unsigned long)rc) + thumb; } regs->ARM_r0 = usig; regs->ARM_sp = (unsigned long)frame; regs->ARM_lr = retcode; regs->ARM_pc = handler & (thumb ? ~1 : ~3); #ifdef CONFIG_CPU_32 regs->ARM_cpsr = cpsr; #endif return 0; } static int setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) { struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame)); int err = 0; if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) return 1; err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]); if (_NSIG_WORDS > 1) { err |= __copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask)); } if (err == 0) err = setup_return(regs, ka, &frame->retcode, frame, usig); return err; } static int setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame)); int err = 0; if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) return 1; __put_user_error(&frame->info, &frame->pinfo, err); __put_user_error(&frame->uc, &frame->puc, err); err |= copy_siginfo_to_user(&frame->info, info); /* Clear all the bits of the ucontext we don't use. */ err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); err |= setup_sigcontext(&frame->uc.uc_mcontext, /*&frame->fpstate,*/ regs, set->sig[0]); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err == 0) err = setup_return(regs, ka, &frame->retcode, frame, usig); if (err == 0) { /* * For realtime signals we must also set the second and third * arguments for the signal handler. * -- Peter Maydell 2000-12-06 */ regs->ARM_r1 = (unsigned long)frame->pinfo; regs->ARM_r2 = (unsigned long)frame->puc; } return err; } /* * OK, we're invoking a handler */ static void handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) { struct task_struct *tsk = current; int usig = sig; int ret; /* * translate the signal */ if (usig < 32 && tsk->exec_domain && tsk->exec_domain->signal_invmap) usig = tsk->exec_domain->signal_invmap[usig]; /* * Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) ret = setup_rt_frame(usig, ka, info, oldset, regs); else ret = setup_frame(usig, ka, oldset, regs); /* * Check that the resulting registers are actually sane. */ ret |= !valid_user_regs(regs); if (ret == 0) { if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (!(ka->sa.sa_flags & SA_NODEFER)) { spin_lock_irq(&tsk->sigmask_lock); sigorsets(&tsk->blocked, &tsk->blocked, &ka->sa.sa_mask); sigaddset(&tsk->blocked, sig); recalc_sigpending(tsk); spin_unlock_irq(&tsk->sigmask_lock); } return; } if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, tsk); } /* * 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. */ asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) { struct k_sigaction *ka; siginfo_t info; int single_stepping; /* * 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 0; if (!oldset) oldset = ¤t->blocked; single_stepping = ptrace_cancel_bpt(current); for (;;) { unsigned long signr; spin_lock_irq (¤t->sigmask_lock); signr = dequeue_signal(¤t->blocked, &info); spin_unlock_irq (¤t->sigmask_lock); if (!signr) break; if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { /* Let the debugger run. */ current->exit_code = signr; current->state = TASK_STOPPED; notify_parent(current, SIGCHLD); schedule(); single_stepping |= ptrace_cancel_bpt(current); /* We're back. Did the debugger cancel the sig? */ if (!(signr = current->exit_code)) continue; current->exit_code = 0; /* The debugger continued. Ignore SIGSTOP. */ if (signr == SIGSTOP) continue; /* Update the siginfo structure. Is this good? */ if (signr != info.si_signo) { info.si_signo = signr; info.si_errno = 0; info.si_code = SI_USER; info.si_pid = current->p_pptr->pid; info.si_uid = current->p_pptr->uid; } /* If the (new) signal is now blocked, requeue it. */ if (sigismember(¤t->blocked, signr)) { send_sig_info(signr, &info, current); continue; } } ka = ¤t->sig->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) { if (signr != SIGCHLD) continue; /* Check for SIGCHLD: it's special. */ while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0) /* nothing */; continue; } if (ka->sa.sa_handler == SIG_DFL) { int exit_code = signr; /* Init gets no signals it doesn't want. */ if (current->pid == 1) continue; switch (signr) { case SIGCONT: case SIGCHLD: case SIGWINCH: continue; case SIGTSTP: case SIGTTIN: case SIGTTOU: if (is_orphaned_pgrp(current->pgrp)) continue; /* FALLTHRU */ case SIGSTOP: current->state = TASK_STOPPED; current->exit_code = signr; if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) notify_parent(current, SIGCHLD); schedule(); continue; case SIGQUIT: case SIGILL: case SIGTRAP: case SIGABRT: case SIGFPE: case SIGSEGV: case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ: if (do_coredump(signr, regs)) exit_code |= 0x80; /* FALLTHRU */ default: sigaddset(¤t->pending.signal, signr); recalc_sigpending(current); current->flags |= PF_SIGNALED; do_exit(exit_code); /* NOTREACHED */ } } /* Are we from a system call? */ if (syscall) { switch (regs->ARM_r0) { case -ERESTARTNOHAND: regs->ARM_r0 = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->ARM_r0 = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: regs->ARM_r0 = regs->ARM_ORIG_r0; regs->ARM_pc -= 4; } } /* Whee! Actually deliver the signal. */ handle_signal(signr, ka, &info, oldset, regs); if (single_stepping) ptrace_set_bpt(current); return 1; } if (syscall && (regs->ARM_r0 == -ERESTARTNOHAND || regs->ARM_r0 == -ERESTARTSYS || regs->ARM_r0 == -ERESTARTNOINTR)) { regs->ARM_r0 = regs->ARM_ORIG_r0; regs->ARM_pc -= 4; } if (single_stepping) ptrace_set_bpt(current); return 0; }