efi_loader: Add boot time services

When an EFI application runs, it has access to a few descriptor and callback
tables to instruct the EFI compliant firmware to do things for it. The bulk
of those interfaces are "boot time services". They handle all object management,
and memory allocation.

This patch adds support for the boot time services and also exposes a system
table, which is the point of entry descriptor table for EFI payloads.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

include/efi_loader.h

@@ -6,15 +6,100 @@
  *  SPDX-License-Identifier:     GPL-2.0+
  */
 
+#include <common.h>
 #include <part_efi.h>
 #include <efi_api.h>
+
+/* No need for efi loader support in SPL */
+#if defined(CONFIG_EFI_LOADER) && !defined(CONFIG_SPL_BUILD)
+
 #include <linux/list.h>
 
+/* #define DEBUG_EFI */
+
+#ifdef DEBUG_EFI
+#define EFI_ENTRY(format, ...) do { \
+	efi_restore_gd(); \
+	printf("EFI: Entry %s(" format ")\n", __func__, ##__VA_ARGS__); \
+	} while(0)
+#else
+#define EFI_ENTRY(format, ...) do { \
+	efi_restore_gd(); \
+	} while(0)
+#endif
+
+#define EFI_EXIT(ret) efi_exit_func(ret);
+
+extern struct efi_system_table systab;
+
 extern const efi_guid_t efi_guid_device_path;
 extern const efi_guid_t efi_guid_loaded_image;
 
+/*
+ * While UEFI objects can have callbacks, you can also call functions on
+ * protocols (classes) themselves. This struct maps a protocol GUID to its
+ * interface (usually a struct with callback functions).
+ */
+struct efi_class_map {
+	const efi_guid_t *guid;
+	const void *interface;
+};
+
+/*
+ * When the UEFI payload wants to open a protocol on an object to get its
+ * interface (usually a struct with callback functions), this struct maps the
+ * protocol GUID to the respective protocol handler open function for that
+ * object protocol combination.
+ */
+struct efi_handler {
+	const efi_guid_t *guid;
+	efi_status_t (EFIAPI *open)(void *handle,
+			efi_guid_t *protocol, void **protocol_interface,
+			void *agent_handle, void *controller_handle,
+			uint32_t attributes);
+};
+
+/*
+ * UEFI has a poor man's OO model where one "object" can be polymorphic and have
+ * multiple different protocols (classes) attached to it.
+ *
+ * This struct is the parent struct for all of our actual implementation objects
+ * that can include it to make themselves an EFI object
+ */
+struct efi_object {
+	/* Every UEFI object is part of a global object list */
+	struct list_head link;
+	/* We support up to 4 "protocols" an object can be accessed through */
+	struct efi_handler protocols[4];
+	/* The object spawner can either use this for data or as identifier */
+	void *handle;
+};
+
+/* This list contains all UEFI objects we know of */
+extern struct list_head efi_obj_list;
+
+/*
+ * Stub implementation for a protocol opener that just returns the handle as
+ * interface
+ */
 efi_status_t efi_return_handle(void *handle,
 		efi_guid_t *protocol, void **protocol_interface,
 		void *agent_handle, void *controller_handle,
 		uint32_t attributes);
+/* Called from places to check whether a timer expired */
+void efi_timer_check(void);
+/* PE loader implementation */
 void *efi_load_pe(void *efi, struct efi_loaded_image *loaded_image_info);
+/* Called once to store the pristine gd pointer */
+void efi_save_gd(void);
+/* Called from EFI_ENTRY on callback entry to put gd into the gd register */
+void efi_restore_gd(void);
+/* Called from EFI_EXIT on callback exit to restore the gd register */
+efi_status_t efi_exit_func(efi_status_t ret);
+
+#else /* defined(EFI_LOADER) && !defined(CONFIG_SPL_BUILD) */
+
+/* No loader configured, stub out EFI_ENTRY */
+static inline void efi_restore_gd(void) { }
+
+#endif