Merge branch 'linux-linaro-lsk-v4.4-android' of git://git.linaro.org/kernel/linux...

[firefly-linux-kernel-4.4.55.git] / arch / arm64 / mm / fault.c

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 7e4423d22d2823e68a4f12f85fc12b297ae2f867..25547993a5ea66e188afdc5680238d1c15d492ff 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -29,7 +29,9 @@
 #include <linux/sched.h>
 #include <linux/highmem.h>
 #include <linux/perf_event.h>
+#include <linux/preempt.h>
 
+#include <asm/bug.h>
 #include <asm/cpufeature.h>
 #include <asm/exception.h>
 #include <asm/debug-monitors.h>
@@ -660,9 +662,17 @@ asmlinkage int __exception do_debug_exception(unsigned long addr,
 NOKPROBE_SYMBOL(do_debug_exception);
 
 #ifdef CONFIG_ARM64_PAN
-void cpu_enable_pan(void *__unused)
+int cpu_enable_pan(void *__unused)
 {
+       /*
+        * We modify PSTATE. This won't work from irq context as the PSTATE
+        * is discarded once we return from the exception.
+        */
+       WARN_ON_ONCE(in_interrupt());
+
        config_sctlr_el1(SCTLR_EL1_SPAN, 0);
+       asm(SET_PSTATE_PAN(1));
+       return 0;
 }
 #endif /* CONFIG_ARM64_PAN */
 
@@ -673,8 +683,9 @@ void cpu_enable_pan(void *__unused)
  * We need to enable the feature at runtime (instead of adding it to
  * PSR_MODE_EL1h) as the feature may not be implemented by the cpu.
  */
-void cpu_enable_uao(void *__unused)
+int cpu_enable_uao(void *__unused)
 {
        asm(SET_PSTATE_UAO(1));
+       return 0;
 }
 #endif /* CONFIG_ARM64_UAO */