diff options
Diffstat (limited to 'arch/tile/kernel/signal.c')
-rw-r--r-- | arch/tile/kernel/signal.c | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/arch/tile/kernel/signal.c b/arch/tile/kernel/signal.c new file mode 100644 index 000000000..87299a6cf --- /dev/null +++ b/arch/tile/kernel/signal.c @@ -0,0 +1,409 @@ +/* + * 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/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 <asm/vdso.h> +#include <arch/interrupts.h> + +#define DEBUG_SIG 0 + +/* + * Do a signal return; undo the signal stack. + */ + +int restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + int err; + + /* Always make any pending restarted system calls return -EINTR */ + current->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); + err = __copy_from_user(regs, sc, sizeof(*regs)); + + /* Ensure that the PL is always set to USER_PL. */ + regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1)); + + regs->faultnum = INT_SWINT_1_SIGRETURN; + + return err; +} + +void signal_fault(const char *type, struct pt_regs *regs, + void __user *frame, int sig) +{ + trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV); + force_sigsegv(sig, current); +} + +/* The assembly shim for this function arranges to ignore the return value. */ +SYSCALL_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe __user *frame = + (struct rt_sigframe __user *)(regs->sp); + sigset_t set; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + set_current_blocked(&set); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + return 0; + +badframe: + signal_fault("bad sigreturn frame", regs, frame, 0); + return 0; +} + +/* + * Set up a signal frame. + */ + +int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) +{ + return __copy_to_user(sc, regs, sizeof(*regs)); +} + +/* + * 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(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + unsigned long restorer; + struct rt_sigframe __user *frame; + int err = 0, sig = ksig->sig; + + frame = get_sigframe(&ksig->ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto err; + + /* Always write at least the signal number for the stack backtracer. */ + if (ksig->ka.sa.sa_flags & SA_SIGINFO) { + /* At sigreturn time, restore the callee-save registers too. */ + err |= copy_siginfo_to_user(&frame->info, &ksig->info); + regs->flags |= PT_FLAGS_RESTORE_REGS; + } else { + err |= __put_user(ksig->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 |= __save_altstack(&frame->uc.uc_stack, regs->sp); + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + goto err; + + restorer = VDSO_SYM(&__vdso_rt_sigreturn); + if (ksig->ka.sa.sa_flags & SA_RESTORER) + restorer = (unsigned long) ksig->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) ksig->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) sig; + regs->regs[1] = (unsigned long) &frame->info; + regs->regs[2] = (unsigned long) &frame->uc; + regs->flags |= PT_FLAGS_CALLER_SAVES; + return 0; + +err: + trace_unhandled_signal("bad sigreturn frame", regs, + (unsigned long)frame, SIGSEGV); + return -EFAULT; +} + +/* + * OK, we're invoking a handler + */ + +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + 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 (!(ksig->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(ksig, oldset, regs); + else +#endif + ret = setup_rt_frame(ksig, oldset, regs); + + signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); +} + +/* + * 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) +{ + struct ksignal ksig; + + /* + * 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 (get_signal(&ksig)) { + /* Whee! Actually deliver the signal. */ + handle_signal(&ksig, regs); + goto done; + } + + /* 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. */ + restore_saved_sigmask(); + +done: + /* Avoid double syscall restart if there are nested signals. */ + regs->faultnum = INT_SWINT_1_SIGRETURN; +} + +int show_unhandled_signals = 1; + +static int __init crashinfo(char *str) +{ + const char *word; + + if (*str == '\0') + show_unhandled_signals = 2; + else if (*str != '=' || kstrtoint(++str, 0, &show_unhandled_signals) != 0) + return 0; + + switch (show_unhandled_signals) { + case 0: + word = "No"; + break; + case 1: + word = "One-line"; + break; + default: + word = "Detailed"; + break; + } + pr_info("%s crash reports will be generated on the console\n", word); + return 1; +} +__setup("crashinfo", crashinfo); + +static void dump_mem(void __user *address) +{ + void __user *addr; + enum { region_size = 256, bytes_per_line = 16 }; + int i, j, k; + int found_readable_mem = 0; + + if (!access_ok(VERIFY_READ, address, 1)) { + pr_err("Not dumping at address 0x%lx (kernel address)\n", + (unsigned long)address); + return; + } + + addr = (void __user *) + (((unsigned long)address & -bytes_per_line) - region_size/2); + if (addr > address) + addr = NULL; + for (i = 0; i < region_size; + addr += bytes_per_line, i += bytes_per_line) { + unsigned char buf[bytes_per_line]; + char line[100]; + if (copy_from_user(buf, addr, bytes_per_line)) + continue; + if (!found_readable_mem) { + pr_err("Dumping memory around address 0x%lx:\n", + (unsigned long)address); + found_readable_mem = 1; + } + j = sprintf(line, REGFMT ":", (unsigned long)addr); + for (k = 0; k < bytes_per_line; ++k) + j += sprintf(&line[j], " %02x", buf[k]); + pr_err("%s\n", line); + } + if (!found_readable_mem) + pr_err("No readable memory around address 0x%lx\n", + (unsigned long)address); +} + +void trace_unhandled_signal(const char *type, struct pt_regs *regs, + unsigned long address, int sig) +{ + struct task_struct *tsk = current; + + if (show_unhandled_signals == 0) + return; + + /* If the signal is handled, don't show it here. */ + if (!is_global_init(tsk)) { + void __user *handler = + tsk->sighand->action[sig-1].sa.sa_handler; + if (handler != SIG_IGN && handler != SIG_DFL) + return; + } + + /* Rate-limit the one-line output, not the detailed output. */ + if (show_unhandled_signals <= 1 && !printk_ratelimit()) + return; + + printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d", + task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, + tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig); + + print_vma_addr(KERN_CONT " in ", regs->pc); + + printk(KERN_CONT "\n"); + + if (show_unhandled_signals > 1) { + switch (sig) { + case SIGILL: + case SIGFPE: + case SIGSEGV: + case SIGBUS: + pr_err("User crash: signal %d, trap %ld, address 0x%lx\n", + sig, regs->faultnum, address); + show_regs(regs); + dump_mem((void __user *)address); + break; + default: + pr_err("User crash: signal %d, trap %ld\n", + sig, regs->faultnum); + break; + } + } +} |