1 files changed, 70 insertions, 0 deletions
diff --git a/src/arch/x86/include/mode_switch.h b/src/arch/x86/include/mode_switch.h
new file mode 100644
index 0000000000..0c46da5c62
--- /dev/null
+++ b/src/arch/x86/include/mode_switch.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <stddef.h>
+#include <stdint.h>
+
+#if ENV_X86_64
+int protected_mode_call_narg(uint32_t arg_count,
+			     uint32_t func_ptr,
+			     uint32_t opt_arg1,
+			     uint32_t opt_arg2);
+
+/*
+ * Drops into protected mode and calls the function, which must have been compiled for x86_32.
+ * After the function returns it enters long mode again.
+ * The function pointer destination must be below 4GiB in physical memory.
+ *
+ * The called function doesn't have arguments and returns an int.
+ */
+static inline int protected_mode_call(void *func)
+{
+	return protected_mode_call_narg(0, (uintptr_t)func, 0, 0);
+}
+
+/*
+ * Drops into protected mode and calls the function, which must have been compiled for x86_32.
+ * After the function returns it enters long mode again.
+ * The function pointer destination must be below 4GiB in physical memory.
+ * Only the lower 32bits of the argument are passed to the called function.
+ *
+ * The called function have one argument and returns an int.
+ */
+static inline int protected_mode_call_1arg(void *func, uint32_t arg1)
+{
+	return protected_mode_call_narg(1, (uintptr_t)func, arg1, 0);
+}
+
+/*
+ * Drops into protected mode and calls the function, which must have been compiled for x86_32.
+ * After the function returns it enters long mode again.
+ * The function pointer destination must be below 4GiB in physical memory.
+ * Only the lower 32bits of the argument are passed to the called function.
+ *
+ * The called function has two arguments and returns an int.
+ */
+static inline int protected_mode_call_2arg(void *func, uint32_t arg1, uint32_t arg2)
+{
+	return protected_mode_call_narg(2, (uintptr_t)func, arg1, arg2);
+}
+#else
+static inline int protected_mode_call(void *func)
+{
+	int (*doit)(void) = func;
+
+	return doit();
+}
+
+static inline int protected_mode_call_1arg(void *func, uint32_t arg1)
+{
+	int (*doit)(uint32_t arg1) = func;
+
+	return doit(arg1);
+}
+
+static inline int protected_mode_call_2arg(void *func, uint32_t arg1, uint32_t arg2)
+{
+	int (*doit)(uint32_t arg1, uint32_t arg2) = func;
+
+	return doit(arg1, arg2);
+}
+#endif