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-rw-r--r--arch/arm64/kernel/kaslr.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
new file mode 100644
index 0000000000..94a269cd1f
--- /dev/null
+++ b/arch/arm64/kernel/kaslr.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
+ */
+
+#include <linux/cache.h>
+#include <linux/init.h>
+#include <linux/printk.h>
+
+#include <asm/cpufeature.h>
+#include <asm/memory.h>
+
+u16 __initdata memstart_offset_seed;
+
+bool __ro_after_init __kaslr_is_enabled = false;
+
+void __init kaslr_init(void)
+{
+ if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val &
+ arm64_sw_feature_override.mask,
+ ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) {
+ pr_info("KASLR disabled on command line\n");
+ return;
+ }
+
+ /*
+ * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical
+ * placement of the image rather than from the seed, so a displacement
+ * of less than MIN_KIMG_ALIGN means that no seed was provided.
+ */
+ if (kaslr_offset() < MIN_KIMG_ALIGN) {
+ pr_warn("KASLR disabled due to lack of seed\n");
+ return;
+ }
+
+ pr_info("KASLR enabled\n");
+ __kaslr_is_enabled = true;
+}