parisc: perf: Fix potential NULL pointer dereference

BugLink: http://bugs.launchpad.net/bugs/1724772

[ Upstream commit 74e3f6e6 ]

Fix potential NULL pointer dereference and clean up
coding style errors (code indent, trailing whitespaces).
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

arch/parisc/kernel/perf.c

@@ -195,8 +195,8 @@ static int perf_config(uint32_t *image_ptr);
 static int perf_release(struct inode *inode, struct file *file);
 static int perf_open(struct inode *inode, struct file *file);
 static ssize_t perf_read(struct file *file, char __user *buf, size_t cnt, loff_t *ppos);
-static ssize_t perf_write(struct file *file, const char __user *buf, size_t count, 
-	loff_t *ppos);
+static ssize_t perf_write(struct file *file, const char __user *buf,
+	size_t count, loff_t *ppos);
 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 static void perf_start_counters(void);
 static int perf_stop_counters(uint32_t *raddr);
@@ -298,8 +298,8 @@ static ssize_t perf_read(struct file *file, char __user *buf, size_t cnt, loff_t
  * called on the processor that the download should happen
  * on.
  */
-static ssize_t perf_write(struct file *file, const char __user *buf, size_t count, 
-	loff_t *ppos)
+static ssize_t perf_write(struct file *file, const char __user *buf,
+	size_t count, loff_t *ppos)
 {
 	int err;
 	size_t image_size;
@@ -809,6 +809,10 @@ static int perf_write_image(uint64_t *memaddr)
 	}
 
 	runway = ioremap_nocache(cpu_device->hpa.start, 4096);
+	if (!runway) {
+		pr_err("perf_write_image: ioremap failed!\n");
+		return -ENOMEM;
+	}
 
 	/* Merge intrigue bits into Runway STATUS 0 */
 	tmp64 = __raw_readq(runway + RUNWAY_STATUS) & 0xffecfffffffffffful;