nios2: Traps exception handling
This patch contains traps exception handling.
Signed-off-by: Ley Foon Tan <lftan@altera.com>
diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
new file mode 100644
index 0000000..b7b97641
--- /dev/null
+++ b/arch/nios2/kernel/traps.c
@@ -0,0 +1,185 @@
+/*
+ * Hardware exception handling
+ *
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ * Copyright (C) 2001 Vic Phillips
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+
+#include <asm/traps.h>
+#include <asm/sections.h>
+#include <asm/uaccess.h>
+
+static DEFINE_SPINLOCK(die_lock);
+
+void die(const char *str, struct pt_regs *regs, long err)
+{
+ console_verbose();
+ spin_lock_irq(&die_lock);
+ pr_warn("Oops: %s, sig: %ld\n", str, err);
+ show_regs(regs);
+ spin_unlock_irq(&die_lock);
+ /*
+ * do_exit() should take care of panic'ing from an interrupt
+ * context so we don't handle it here
+ */
+ do_exit(err);
+}
+
+void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
+{
+ siginfo_t info;
+
+ if (!user_mode(regs))
+ die("Exception in kernel mode", regs, signo);
+
+ info.si_signo = signo;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = (void __user *) addr;
+ force_sig_info(signo, &info, current);
+}
+
+/*
+ * The show_stack is an external API which we do not use ourselves.
+ */
+
+int kstack_depth_to_print = 48;
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+ unsigned long *endstack, addr;
+ int i;
+
+ if (!stack) {
+ if (task)
+ stack = (unsigned long *)task->thread.ksp;
+ else
+ stack = (unsigned long *)&stack;
+ }
+
+ addr = (unsigned long) stack;
+ endstack = (unsigned long *) PAGE_ALIGN(addr);
+
+ pr_emerg("Stack from %08lx:", (unsigned long)stack);
+ for (i = 0; i < kstack_depth_to_print; i++) {
+ if (stack + 1 > endstack)
+ break;
+ if (i % 8 == 0)
+ pr_emerg("\n ");
+ pr_emerg(" %08lx", *stack++);
+ }
+
+ pr_emerg("\nCall Trace:");
+ i = 0;
+ while (stack + 1 <= endstack) {
+ addr = *stack++;
+ /*
+ * If the address is either in the text segment of the
+ * kernel, or in the region which contains vmalloc'ed
+ * memory, it *may* be the address of a calling
+ * routine; if so, print it so that someone tracing
+ * down the cause of the crash will be able to figure
+ * out the call path that was taken.
+ */
+ if (((addr >= (unsigned long) _stext) &&
+ (addr <= (unsigned long) _etext))) {
+ if (i % 4 == 0)
+ pr_emerg("\n ");
+ pr_emerg(" [<%08lx>]", addr);
+ i++;
+ }
+ }
+ pr_emerg("\n");
+}
+
+void __init trap_init(void)
+{
+ /* Nothing to do here */
+}
+
+/* Breakpoint handler */
+asmlinkage void breakpoint_c(struct pt_regs *fp)
+{
+ /*
+ * The breakpoint entry code has moved the PC on by 4 bytes, so we must
+ * move it back. This could be done on the host but we do it here
+ * because monitor.S of JTAG gdbserver does it too.
+ */
+ fp->ea -= 4;
+ _exception(SIGTRAP, fp, TRAP_BRKPT, fp->ea);
+}
+
+#ifndef CONFIG_NIOS2_ALIGNMENT_TRAP
+/* Alignment exception handler */
+asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause)
+{
+ unsigned long addr = RDCTL(CTL_BADADDR);
+
+ cause >>= 2;
+ fp->ea -= 4;
+
+ if (fixup_exception(fp))
+ return;
+
+ if (!user_mode(fp)) {
+ pr_alert("Unaligned access from kernel mode, this might be a hardware\n");
+ pr_alert("problem, dump registers and restart the instruction\n");
+ pr_alert(" BADADDR 0x%08lx\n", addr);
+ pr_alert(" cause %d\n", cause);
+ pr_alert(" op-code 0x%08lx\n", *(unsigned long *)(fp->ea));
+ show_regs(fp);
+ return;
+ }
+
+ _exception(SIGBUS, fp, BUS_ADRALN, addr);
+}
+#endif /* CONFIG_NIOS2_ALIGNMENT_TRAP */
+
+/* Illegal instruction handler */
+asmlinkage void handle_illegal_c(struct pt_regs *fp)
+{
+ fp->ea -= 4;
+ _exception(SIGILL, fp, ILL_ILLOPC, fp->ea);
+}
+
+/* Supervisor instruction handler */
+asmlinkage void handle_supervisor_instr(struct pt_regs *fp)
+{
+ fp->ea -= 4;
+ _exception(SIGILL, fp, ILL_PRVOPC, fp->ea);
+}
+
+/* Division error handler */
+asmlinkage void handle_diverror_c(struct pt_regs *fp)
+{
+ fp->ea -= 4;
+ _exception(SIGFPE, fp, FPE_INTDIV, fp->ea);
+}
+
+/* Unhandled exception handler */
+asmlinkage void unhandled_exception(struct pt_regs *regs, int cause)
+{
+ unsigned long addr = RDCTL(CTL_BADADDR);
+
+ cause /= 4;
+
+ pr_emerg("Unhandled exception #%d in %s mode (badaddr=0x%08lx)\n",
+ cause, user_mode(regs) ? "user" : "kernel", addr);
+
+ regs->ea -= 4;
+ show_regs(regs);
+
+ pr_emerg("opcode: 0x%08lx\n", *(unsigned long *)(regs->ea));
+}