Initial import

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;
+		}
+	}
+}