arm64: efi: add EFI stub

This patch adds PE/COFF header fields to the start of the kernel
Image so that it appears as an EFI application to UEFI firmware.
An EFI stub is included to allow direct booting of the kernel
Image.

Signed-off-by: Mark Salter <msalter@redhat.com>
[Add support in PE/COFF header for signed images]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 247 insertions, 0 deletions

diff --git a/drivers/firmware/efi/arm-stub.c b/drivers/firmware/efi/arm-stub.c
new file mode 100644
index 000000000000..19239a9b7e29
--- /dev/null
+++ b/drivers/firmware/efi/arm-stub.c
@@ -0,0 +1,247 @@
+/*
+ * EFI stub implementation that is shared by arm and arm64 architectures.
+ * This should be #included by the EFI stub implementation files.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ *     Roy Franz <roy.franz@linaro.org
+ * Copyright (C) 2013 Red Hat, Inc.
+ *     Mark Salter <msalter@redhat.com>
+ *
+ * This file is part of the Linux kernel, and is made available under the
+ * terms of the GNU General Public License version 2.
+ *
+ */
+
+static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
+				    void *__image, void **__fh)
+{
+	efi_file_io_interface_t *io;
+	efi_loaded_image_t *image = __image;
+	efi_file_handle_t *fh;
+	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
+	efi_status_t status;
+	void *handle = (void *)(unsigned long)image->device_handle;
+
+	status = sys_table_arg->boottime->handle_protocol(handle,
+				 &fs_proto, (void **)&io);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
+		return status;
+	}
+
+	status = io->open_volume(io, &fh);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table_arg, "Failed to open volume\n");
+
+	*__fh = fh;
+	return status;
+}
+static efi_status_t efi_file_close(void *handle)
+{
+	efi_file_handle_t *fh = handle;
+
+	return fh->close(handle);
+}
+
+static efi_status_t
+efi_file_read(void *handle, unsigned long *size, void *addr)
+{
+	efi_file_handle_t *fh = handle;
+
+	return fh->read(handle, size, addr);
+}
+
+
+static efi_status_t
+efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
+	      efi_char16_t *filename_16, void **handle, u64 *file_sz)
+{
+	efi_file_handle_t *h, *fh = __fh;
+	efi_file_info_t *info;
+	efi_status_t status;
+	efi_guid_t info_guid = EFI_FILE_INFO_ID;
+	unsigned long info_sz;
+
+	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to open file: ");
+		efi_char16_printk(sys_table_arg, filename_16);
+		efi_printk(sys_table_arg, "\n");
+		return status;
+	}
+
+	*handle = h;
+
+	info_sz = 0;
+	status = h->get_info(h, &info_guid, &info_sz, NULL);
+	if (status != EFI_BUFFER_TOO_SMALL) {
+		efi_printk(sys_table_arg, "Failed to get file info size\n");
+		return status;
+	}
+
+grow:
+	status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
+				 info_sz, (void **)&info);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
+		return status;
+	}
+
+	status = h->get_info(h, &info_guid, &info_sz,
+						   info);
+	if (status == EFI_BUFFER_TOO_SMALL) {
+		sys_table_arg->boottime->free_pool(info);
+		goto grow;
+	}
+
+	*file_sz = info->file_size;
+	sys_table_arg->boottime->free_pool(info);
+
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table_arg, "Failed to get initrd info\n");
+
+	return status;
+}
+
+
+
+static void efi_char16_printk(efi_system_table_t *sys_table_arg,
+			      efi_char16_t *str)
+{
+	struct efi_simple_text_output_protocol *out;
+
+	out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
+	out->output_string(out, str);
+}
+
+
+/*
+ * This function handles the architcture specific differences between arm and
+ * arm64 regarding where the kernel image must be loaded and any memory that
+ * must be reserved. On failure it is required to free all
+ * all allocations it has made.
+ */
+static efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
+					unsigned long *image_addr,
+					unsigned long *image_size,
+					unsigned long *reserve_addr,
+					unsigned long *reserve_size,
+					unsigned long dram_base,
+					efi_loaded_image_t *image);
+/*
+ * EFI entry point for the arm/arm64 EFI stubs.  This is the entrypoint
+ * that is described in the PE/COFF header.  Most of the code is the same
+ * for both archictectures, with the arch-specific code provided in the
+ * handle_kernel_image() function.
+ */
+unsigned long __init efi_entry(void *handle, efi_system_table_t *sys_table,
+			       unsigned long *image_addr)
+{
+	efi_loaded_image_t *image;
+	efi_status_t status;
+	unsigned long image_size = 0;
+	unsigned long dram_base;
+	/* addr/point and size pairs for memory management*/
+	unsigned long initrd_addr;
+	u64 initrd_size = 0;
+	unsigned long fdt_addr;  /* Original DTB */
+	u64 fdt_size = 0;  /* We don't get size from configuration table */
+	char *cmdline_ptr = NULL;
+	int cmdline_size = 0;
+	unsigned long new_fdt_addr;
+	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
+	unsigned long reserve_addr = 0;
+	unsigned long reserve_size = 0;
+
+	/* Check if we were booted by the EFI firmware */
+	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
+		goto fail;
+
+	pr_efi(sys_table, "Booting Linux Kernel...\n");
+
+	/*
+	 * Get a handle to the loaded image protocol.  This is used to get
+	 * information about the running image, such as size and the command
+	 * line.
+	 */
+	status = sys_table->boottime->handle_protocol(handle,
+					&loaded_image_proto, (void *)&image);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
+		goto fail;
+	}
+
+	dram_base = get_dram_base(sys_table);
+	if (dram_base == EFI_ERROR) {
+		pr_efi_err(sys_table, "Failed to find DRAM base\n");
+		goto fail;
+	}
+	status = handle_kernel_image(sys_table, image_addr, &image_size,
+				     &reserve_addr,
+				     &reserve_size,
+				     dram_base, image);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table, "Failed to relocate kernel\n");
+		goto fail;
+	}
+
+	/*
+	 * Get the command line from EFI, using the LOADED_IMAGE
+	 * protocol. We are going to copy the command line into the
+	 * device tree, so this can be allocated anywhere.
+	 */
+	cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
+	if (!cmdline_ptr) {
+		pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
+		goto fail_free_image;
+	}
+
+	/* Load a device tree from the configuration table, if present. */
+	fdt_addr = (uintptr_t)get_fdt(sys_table);
+	if (!fdt_addr) {
+		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
+					      "dtb=",
+					      ~0UL, (unsigned long *)&fdt_addr,
+					      (unsigned long *)&fdt_size);
+
+		if (status != EFI_SUCCESS) {
+			pr_efi_err(sys_table, "Failed to load device tree!\n");
+			goto fail_free_cmdline;
+		}
+	}
+
+	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
+				      "initrd=", dram_base + SZ_512M,
+				      (unsigned long *)&initrd_addr,
+				      (unsigned long *)&initrd_size);
+	if (status != EFI_SUCCESS)
+		pr_efi_err(sys_table, "Failed initrd from command line!\n");
+
+	new_fdt_addr = fdt_addr;
+	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
+				&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
+				initrd_addr, initrd_size, cmdline_ptr,
+				fdt_addr, fdt_size);
+
+	/*
+	 * If all went well, we need to return the FDT address to the
+	 * calling function so it can be passed to kernel as part of
+	 * the kernel boot protocol.
+	 */
+	if (status == EFI_SUCCESS)
+		return new_fdt_addr;
+
+	pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
+
+	efi_free(sys_table, initrd_size, initrd_addr);
+	efi_free(sys_table, fdt_size, fdt_addr);
+
+fail_free_cmdline:
+	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
+
+fail_free_image:
+	efi_free(sys_table, image_size, *image_addr);
+	efi_free(sys_table, reserve_size, reserve_addr);
+fail:
+	return EFI_ERROR;
+}