Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-rtlsk-v4.4-16.12-rt

1 files changed, 12 insertions, 5 deletions

diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index b616e365cee3..5a0b1088c17c 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -1,7 +1,9 @@
 #include <linux/ftrace.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
+#include <asm/alternative.h>
 #include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
 #include <asm/debug-monitors.h>
 #include <asm/pgtable.h>
 #include <asm/memory.h>
@@ -88,11 +90,16 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 		ret = fn(arg);
 
 		/*
-		 * Never gets here, unless the suspend finisher fails.
-		 * Successful cpu_suspend() should return from cpu_resume(),
-		 * returning through this code path is considered an error
-		 * If the return value is set to 0 force ret = -EOPNOTSUPP
-		 * to make sure a proper error condition is propagated
+		 * PSTATE was not saved over suspend/resume, re-enable any
+		 * detected features that might not have been set correctly.
+		 */
+		asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,
+				CONFIG_ARM64_PAN));
+
+		/*
+		 * Restore HW breakpoint registers to sane values
+		 * before debug exceptions are possibly reenabled
+		 * through local_dbg_restore.
 		 */
 		if (!ret)
 			ret = -EOPNOTSUPP;