| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright 2010 Tilera Corporation. All Rights Reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation, version 2. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
| * NON INFRINGEMENT. See the GNU General Public License for |
| * more details. |
| */ |
| |
| #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/unistd.h> |
| #include <linux/stddef.h> |
| #include <linux/personality.h> |
| #include <linux/suspend.h> |
| #include <linux/ptrace.h> |
| #include <linux/elf.h> |
| #include <linux/compat.h> |
| #include <linux/syscalls.h> |
| #include <linux/uaccess.h> |
| #include <asm/processor.h> |
| #include <asm/ucontext.h> |
| #include <asm/sigframe.h> |
| #include <asm/syscalls.h> |
| #include <arch/interrupts.h> |
| |
| #define DEBUG_SIG 0 |
| |
| #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) |
| |
| |
| SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss, |
| stack_t __user *, uoss, struct pt_regs *, regs) |
| { |
| return do_sigaltstack(uss, uoss, regs->sp); |
| } |
| |
| |
| /* |
| * Do a signal return; undo the signal stack. |
| */ |
| |
| int restore_sigcontext(struct pt_regs *regs, |
| struct sigcontext __user *sc, long *pr0) |
| { |
| int err = 0; |
| int i; |
| |
| /* Always make any pending restarted system calls return -EINTR */ |
| current_thread_info()->restart_block.fn = do_no_restart_syscall; |
| |
| /* |
| * Enforce that sigcontext is like pt_regs, and doesn't mess |
| * up our stack alignment rules. |
| */ |
| BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs)); |
| BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0); |
| |
| for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) |
| err |= __get_user(regs->regs[i], &sc->gregs[i]); |
| |
| regs->faultnum = INT_SWINT_1_SIGRETURN; |
| |
| err |= __get_user(*pr0, &sc->gregs[0]); |
| return err; |
| } |
| |
| /* sigreturn() returns long since it restores r0 in the interrupted code. */ |
| SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs) |
| { |
| struct rt_sigframe __user *frame = |
| (struct rt_sigframe __user *)(regs->sp); |
| sigset_t set; |
| long r0; |
| |
| 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->sp) == -EFAULT) |
| goto badframe; |
| |
| return r0; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| /* |
| * Set up a signal frame. |
| */ |
| |
| int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) |
| { |
| int i, err = 0; |
| |
| for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) |
| err |= __put_user(regs->regs[i], &sc->gregs[i]); |
| |
| return err; |
| } |
| |
| /* |
| * Determine which stack to use.. |
| */ |
| static inline void __user *get_sigframe(struct k_sigaction *ka, |
| struct pt_regs *regs, |
| size_t frame_size) |
| { |
| unsigned long sp; |
| |
| /* Default to using normal stack */ |
| sp = regs->sp; |
| |
| /* |
| * If we are on the alternate signal stack and would overflow |
| * it, don't. Return an always-bogus address instead so we |
| * will die with SIGSEGV. |
| */ |
| if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size))) |
| return (void __user __force *)-1UL; |
| |
| /* This is the X/Open sanctioned signal stack switching. */ |
| if (ka->sa.sa_flags & SA_ONSTACK) { |
| if (sas_ss_flags(sp) == 0) |
| sp = current->sas_ss_sp + current->sas_ss_size; |
| } |
| |
| sp -= frame_size; |
| /* |
| * Align the stack pointer according to the TILE ABI, |
| * i.e. so that on function entry (sp & 15) == 0. |
| */ |
| sp &= -16UL; |
| return (void __user *) sp; |
| } |
| |
| static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| unsigned long restorer; |
| struct rt_sigframe __user *frame; |
| int err = 0; |
| int usig; |
| |
| frame = get_sigframe(ka, regs, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| goto give_sigsegv; |
| |
| usig = current_thread_info()->exec_domain |
| && current_thread_info()->exec_domain->signal_invmap |
| && sig < 32 |
| ? current_thread_info()->exec_domain->signal_invmap[sig] |
| : sig; |
| |
| /* Always write at least the signal number for the stack backtracer. */ |
| if (ka->sa.sa_flags & SA_SIGINFO) { |
| /* At sigreturn time, restore the callee-save registers too. */ |
| err |= copy_siginfo_to_user(&frame->info, info); |
| regs->flags |= PT_FLAGS_RESTORE_REGS; |
| } else { |
| err |= __put_user(info->si_signo, &frame->info.si_signo); |
| } |
| |
| /* Create the ucontext. */ |
| err |= __clear_user(&frame->save_area, sizeof(frame->save_area)); |
| err |= __put_user(0, &frame->uc.uc_flags); |
| err |= __put_user(NULL, &frame->uc.uc_link); |
| err |= __put_user((void __user *)(current->sas_ss_sp), |
| &frame->uc.uc_stack.ss_sp); |
| err |= __put_user(sas_ss_flags(regs->sp), |
| &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); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| if (err) |
| goto give_sigsegv; |
| |
| restorer = VDSO_BASE; |
| if (ka->sa.sa_flags & SA_RESTORER) |
| restorer = (unsigned long) ka->sa.sa_restorer; |
| |
| /* |
| * Set up registers for signal handler. |
| * Registers that we don't modify keep the value they had from |
| * user-space at the time we took the signal. |
| * We always pass siginfo and mcontext, regardless of SA_SIGINFO, |
| * since some things rely on this (e.g. glibc's debug/segfault.c). |
| */ |
| regs->pc = (unsigned long) ka->sa.sa_handler; |
| regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */ |
| regs->sp = (unsigned long) frame; |
| regs->lr = restorer; |
| regs->regs[0] = (unsigned long) usig; |
| regs->regs[1] = (unsigned long) &frame->info; |
| regs->regs[2] = (unsigned long) &frame->uc; |
| regs->flags |= PT_FLAGS_CALLER_SAVES; |
| |
| /* |
| * Notify any tracer that was single-stepping it. |
| * The tracer may want to single-step inside the |
| * handler too. |
| */ |
| if (test_thread_flag(TIF_SINGLESTEP)) |
| ptrace_notify(SIGTRAP); |
| |
| return 0; |
| |
| give_sigsegv: |
| force_sigsegv(sig, current); |
| return -EFAULT; |
| } |
| |
| /* |
| * OK, we're invoking a handler |
| */ |
| |
| static int handle_signal(unsigned long sig, siginfo_t *info, |
| struct k_sigaction *ka, sigset_t *oldset, |
| struct pt_regs *regs) |
| { |
| int ret; |
| |
| |
| /* Are we from a system call? */ |
| if (regs->faultnum == INT_SWINT_1) { |
| /* If so, check system call restarting.. */ |
| switch (regs->regs[0]) { |
| case -ERESTART_RESTARTBLOCK: |
| case -ERESTARTNOHAND: |
| regs->regs[0] = -EINTR; |
| break; |
| |
| case -ERESTARTSYS: |
| if (!(ka->sa.sa_flags & SA_RESTART)) { |
| regs->regs[0] = -EINTR; |
| break; |
| } |
| /* fallthrough */ |
| case -ERESTARTNOINTR: |
| /* Reload caller-saves to restore r0..r5 and r10. */ |
| regs->flags |= PT_FLAGS_CALLER_SAVES; |
| regs->regs[0] = regs->orig_r0; |
| regs->pc -= 8; |
| } |
| } |
| |
| /* Set up the stack frame */ |
| #ifdef CONFIG_COMPAT |
| if (is_compat_task()) |
| ret = compat_setup_rt_frame(sig, ka, info, oldset, regs); |
| else |
| #endif |
| ret = setup_rt_frame(sig, ka, info, oldset, regs); |
| if (ret == 0) { |
| /* This code is only called from system calls or from |
| * the work_pending path in the return-to-user code, and |
| * either way we can re-enable interrupts unconditionally. |
| */ |
| 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. |
| */ |
| void do_signal(struct pt_regs *regs) |
| { |
| siginfo_t info; |
| int signr; |
| struct k_sigaction ka; |
| sigset_t *oldset; |
| |
| /* |
| * i386 will check if we're coming from kernel mode and bail out |
| * here. In my experience this just turns weird crashes into |
| * weird spin-hangs. But if we find a case where this seems |
| * helpful, we can reinstate the check on "!user_mode(regs)". |
| */ |
| |
| 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) { |
| /* Whee! Actually deliver the signal. */ |
| if (handle_signal(signr, &info, &ka, oldset, regs) == 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; |
| } |
| |
| return; |
| } |
| |
| /* Did we come from a system call? */ |
| if (regs->faultnum == INT_SWINT_1) { |
| /* Restart the system call - no handlers present */ |
| switch (regs->regs[0]) { |
| case -ERESTARTNOHAND: |
| case -ERESTARTSYS: |
| case -ERESTARTNOINTR: |
| regs->flags |= PT_FLAGS_CALLER_SAVES; |
| regs->regs[0] = regs->orig_r0; |
| regs->pc -= 8; |
| break; |
| |
| case -ERESTART_RESTARTBLOCK: |
| regs->flags |= PT_FLAGS_CALLER_SAVES; |
| regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall; |
| regs->pc -= 8; |
| break; |
| } |
| } |
| |
| /* If there's no signal to deliver, 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); |
| } |
| } |