fiq_debugger: Add fiq_watchdog_triggered api

Dumps registers and stacktrace into console-ramoops when called
from a watchdog fiq.

Change-Id: Ib6fab5a52f670db18e64214d5e4890e8292a749c
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Git-commit: 1b48727337de9e12237583931315cc6d85532415
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Ian Maund <imaund@codeaurora.org>

drivers/staging/android/fiq_debugger/Kconfig

@@ -41,3 +41,9 @@ config FIQ_DEBUGGER_CONSOLE_DEFAULT_ENABLE
 	help
 	  If enabled, this puts the fiq debugger into console mode by default.
 	  Otherwise, the fiq debugger will start out in debug mode.
+
+config FIQ_WATCHDOG
+	bool
+	select FIQ_DEBUGGER
+	select PSTORE_RAM
+	default n

drivers/staging/android/fiq_debugger/Makefile

@@ -1,3 +1,4 @@
 obj-y			+= fiq_debugger.o
 obj-$(CONFIG_ARM)	+= fiq_debugger_arm.o
-obj-$(CONFIG_ARM64)	+= fiq_debugger_arm64.o
+obj-$(CONFIG_ARM64)	+= fiq_debugger_arm64.o
+obj-$(CONFIG_FIQ_WATCHDOG)	+= fiq_watchdog.o

drivers/staging/android/fiq_debugger/fiq_watchdog.c

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/pstore_ram.h>
+
+#include "fiq_watchdog.h"
+#include "fiq_debugger_priv.h"
+
+static DEFINE_RAW_SPINLOCK(fiq_watchdog_lock);
+
+static void fiq_watchdog_printf(struct fiq_debugger_output *output,
+				const char *fmt, ...)
+{
+	char buf[256];
+	va_list ap;
+	int len;
+
+	va_start(ap, fmt);
+	len = vscnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	ramoops_console_write_buf(buf, len);
+}
+
+struct fiq_debugger_output fiq_watchdog_output = {
+	.printf = fiq_watchdog_printf,
+};
+
+void fiq_watchdog_triggered(const struct pt_regs *regs, void *svc_sp)
+{
+	char msg[24];
+	int len;
+
+	raw_spin_lock(&fiq_watchdog_lock);
+
+	len = scnprintf(msg, sizeof(msg), "watchdog fiq cpu %d\n",
+			THREAD_INFO(svc_sp)->cpu);
+	ramoops_console_write_buf(msg, len);
+
+	fiq_debugger_dump_stacktrace(&fiq_watchdog_output, regs, 100, svc_sp);
+
+	raw_spin_unlock(&fiq_watchdog_lock);
+}

drivers/staging/android/fiq_debugger/fiq_watchdog.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _FIQ_WATCHDOG_H_
+#define _FIQ_WATCHDOG_H_
+
+void fiq_watchdog_triggered(const struct pt_regs *regs, void *svc_sp);
+
+#endif