1 files changed, 48 insertions, 0 deletions
diff --git a/arch/s390/kernel/skey.c b/arch/s390/kernel/skey.c
new file mode 100644
index 000000000000..ba049fd103c2
--- /dev/null
+++ b/arch/s390/kernel/skey.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <asm/rwonce.h>
+#include <asm/page.h>
+#include <asm/skey.h>
+
+int skey_regions_initialized;
+
+static inline unsigned long load_real_address(unsigned long address)
+{
+	unsigned long real;
+
+	asm volatile(
+		"	lra	%[real],0(%[address])\n"
+		: [real] "=d" (real)
+		: [address] "a" (address)
+		: "cc");
+	return real;
+}
+
+/*
+ * Initialize storage keys of registered memory regions with the
+ * default key. This is useful for code which is executed with a
+ * non-default access key.
+ */
+void __skey_regions_initialize(void)
+{
+	unsigned long address, real;
+	struct skey_region *r, *end;
+
+	r = __skey_region_start;
+	end = __skey_region_end;
+	while (r < end) {
+		address = r->start & PAGE_MASK;
+		do {
+			real = load_real_address(address);
+			page_set_storage_key(real, PAGE_DEFAULT_KEY, 1);
+			address += PAGE_SIZE;
+		} while (address < r->end);
+		r++;
+	}
+	/*
+	 * Make sure storage keys are initialized before
+	 * skey_regions_initialized is changed.
+	 */
+	barrier();
+	WRITE_ONCE(skey_regions_initialized, 1);
+}