diff options
Diffstat (limited to 'arch/tile/kernel/signal.c')
| -rw-r--r-- | arch/tile/kernel/signal.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/arch/tile/kernel/signal.c b/arch/tile/kernel/signal.c new file mode 100644 index 00000000000..ce183aa1492 --- /dev/null +++ b/arch/tile/kernel/signal.c @@ -0,0 +1,361 @@ +/* + * 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))) + + +long _sys_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. */ +long _sys_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); + } +} |