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-rw-r--r--lib/stack_protector/aarch32/asm_stack_protector.S34
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/stack_protector/aarch32/asm_stack_protector.S b/lib/stack_protector/aarch32/asm_stack_protector.S
new file mode 100644
index 0000000..19b7525
--- /dev/null
+++ b/lib/stack_protector/aarch32/asm_stack_protector.S
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <assert_macros.S>
+
+ .globl update_stack_protector_canary
+
+/* -----------------------------------------------------------------------
+ * void update_stack_protector_canary(void)
+ *
+ * Change the value of the canary used for stack smashing attacks protection.
+ * Note: This must be called when it is safe to call C code, but this cannot be
+ * called by C code. Doing this will make the check fail when the calling
+ * function returns.
+ * -----------------------------------------------------------------------
+ */
+
+func update_stack_protector_canary
+ /* Use r4 as it is callee-saved */
+ mov r4, lr
+ bl plat_get_stack_protector_canary
+
+ /* Update the canary with the returned value */
+ ldr r1, =__stack_chk_guard
+ str r0, [r1]
+ bx r4
+endfunc update_stack_protector_canary
+
+