microblaze_v8: exception handling

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 124 insertions, 0 deletions

diff --git a/arch/microblaze/kernel/exceptions.c b/arch/microblaze/kernel/exceptions.c
new file mode 100644
index 000000000000..4a8a4064c7ee
--- /dev/null
+++ b/arch/microblaze/kernel/exceptions.c
@@ -0,0 +1,124 @@
+/*
+ * HW exception handling
+ *
+ * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2008 PetaLogix
+ *
+ * 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.
+ */
+
+/*
+ * This file handles the architecture-dependent parts of hardware exceptions
+ */
+
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+
+#include <asm/exceptions.h>
+#include <asm/entry.h>		/* For KM CPU var */
+#include <asm/uaccess.h>
+#include <asm/errno.h>
+#include <asm/ptrace.h>
+#include <asm/current.h>
+
+#define MICROBLAZE_ILL_OPCODE_EXCEPTION	0x02
+#define MICROBLAZE_IBUS_EXCEPTION	0x03
+#define MICROBLAZE_DBUS_EXCEPTION	0x04
+#define MICROBLAZE_DIV_ZERO_EXCEPTION	0x05
+#define MICROBLAZE_FPU_EXCEPTION	0x06
+#define MICROBLAZE_PRIVILEG_EXCEPTION	0x07
+
+static DEFINE_SPINLOCK(die_lock);
+
+void die(const char *str, struct pt_regs *fp, long err)
+{
+	console_verbose();
+	spin_lock_irq(&die_lock);
+	printk(KERN_WARNING "Oops: %s, sig: %ld\n", str, err);
+	show_regs(fp);
+	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 signr, struct pt_regs *regs, int code, unsigned long addr)
+{
+	siginfo_t info;
+
+	if (kernel_mode(regs)) {
+		debugger(regs);
+		die("Exception in kernel mode", regs, signr);
+	}
+	info.si_signo = signr;
+	info.si_errno = 0;
+	info.si_code = code;
+	info.si_addr = (void __user *) addr;
+	force_sig_info(signr, &info, current);
+}
+
+asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
+							int fsr, int addr)
+{
+#if 0
+	printk(KERN_WARNING "Exception %02x in %s mode, FSR=%08x PC=%08x ESR=%08x\n",
+			type, user_mode(regs) ? "user" : "kernel", fsr,
+			(unsigned int) regs->pc, (unsigned int) regs->esr);
+#endif
+
+	switch (type & 0x1F) {
+	case MICROBLAZE_ILL_OPCODE_EXCEPTION:
+		_exception(SIGILL, regs, ILL_ILLOPC, addr);
+		break;
+	case MICROBLAZE_IBUS_EXCEPTION:
+		if (user_mode(regs)) {
+			printk(KERN_WARNING "Instruction bus error exception in user mode.\n");
+			_exception(SIGBUS, regs, BUS_ADRERR, addr);
+			return;
+		}
+		printk(KERN_WARNING "Instruction bus error exception in kernel mode.\n");
+		die("bus exception", regs, SIGBUS);
+		break;
+	case MICROBLAZE_DBUS_EXCEPTION:
+		if (user_mode(regs)) {
+			printk(KERN_WARNING "Data bus error exception in user mode.\n");
+			_exception(SIGBUS, regs, BUS_ADRERR, addr);
+			return;
+		}
+		printk(KERN_WARNING "Data bus error exception in kernel mode.\n");
+		die("bus exception", regs, SIGBUS);
+		break;
+	case MICROBLAZE_DIV_ZERO_EXCEPTION:
+		printk(KERN_WARNING "Divide by zero exception\n");
+		_exception(SIGILL, regs, ILL_ILLOPC, addr);
+		break;
+
+	case MICROBLAZE_FPU_EXCEPTION:
+		/* IEEE FP exception */
+		/* I removed fsr variable and use code var for storing fsr */
+		if (fsr & FSR_IO)
+			fsr = FPE_FLTINV;
+		else if (fsr & FSR_OF)
+			fsr = FPE_FLTOVF;
+		else if (fsr & FSR_UF)
+			fsr = FPE_FLTUND;
+		else if (fsr & FSR_DZ)
+			fsr = FPE_FLTDIV;
+		else if (fsr & FSR_DO)
+			fsr = FPE_FLTRES;
+		_exception(SIGFPE, regs, fsr, addr);
+		break;
+
+	default:
+		printk(KERN_WARNING "Unexpected exception %02x "
+			"PC=%08x in %s mode\n", type, (unsigned int) addr,
+			kernel_mode(regs) ? "kernel" : "user");
+	}
+	return;
+}