Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / mips / include / asm / stackprotector.h

diff --git a/kernel/arch/mips/include/asm/stackprotector.h b/kernel/arch/mips/include/asm/stackprotector.h
new file mode 100644 (file)
index 0000000..eb9b103
--- /dev/null
+++ b/kernel/arch/mips/include/asm/stackprotector.h
@@ -0,0 +1,40 @@
+/*
+ * GCC stack protector support.
+ *
+ * (This is directly adopted from the ARM implementation)
+ *
+ * Stack protector works by putting predefined pattern at the start of
+ * the stack frame and verifying that it hasn't been overwritten when
+ * returning from the function.  The pattern is called stack canary
+ * and gcc expects it to be defined by a global variable called
+ * "__stack_chk_guard" on MIPS.  This unfortunately means that on SMP
+ * we cannot have a different canary value per task.
+ */
+
+#ifndef _ASM_STACKPROTECTOR_H
+#define _ASM_STACKPROTECTOR_H 1
+
+#include <linux/random.h>
+#include <linux/version.h>
+
+extern unsigned long __stack_chk_guard;
+
+/*
+ * Initialize the stackprotector canary value.
+ *
+ * NOTE: this must only be called from functions that never return,
+ * and it must always be inlined.
+ */
+static __always_inline void boot_init_stack_canary(void)
+{
+       unsigned long canary;
+
+       /* Try to get a semi random initial value. */
+       get_random_bytes(&canary, sizeof(canary));
+       canary ^= LINUX_VERSION_CODE;
+
+       current->stack_canary = canary;
+       __stack_chk_guard = current->stack_canary;
+}
+
+#endif /* _ASM_STACKPROTECTOR_H */