[PATCH v2 06/10] efi: payload: split image handling from legacy handover boot and add linux x86 image filetype

[chalianis1@gmail.com]

From: Chali Anis <chalianis1@gmail.com>

The handover boot support is Linux-specific and can be disabled
with CONFIG_EFI_HANDOVER_PROTOCOL. In preparation for adding a compliant
boot method, move the handover-specific parts into their own file.
Introduce a new filetype for x86 Linux kernel images by checking for
the "HdrS" magic (0x53726448) at offset 0x202 in the setup header.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
Signed-off-by: Chali Anis <chalianis1@gmail.com>
---
 common/filetype.c          |   3 +
 efi/payload/Kconfig        |   5 +
 efi/payload/Makefile       |   1 +
 efi/payload/handover.c     | 154 +++++++++++++++++++++++++++++
 efi/payload/image.c        | 192 +++++--------------------------------
 efi/payload/image.h        |  14 +++
 efi/payload/setup_header.h |  63 ++++++++++++
 include/filetype.h         |   6 ++
 8 files changed, 269 insertions(+), 169 deletions(-)
 create mode 100644 efi/payload/handover.c
 create mode 100644 efi/payload/image.h
 create mode 100644 efi/payload/setup_header.h

diff --git a/common/filetype.c b/common/filetype.c
index eb397a175cb6..72f84442cae9 100644
--- a/common/filetype.c
+++ b/common/filetype.c
@@ -87,6 +87,7 @@ static const struct filetype_str filetype_str[] = {
 	[filetype_zstd_compressed] = { "ZSTD compressed", "zstd" },
 	[filetype_rockchip_rkss_image] = { "Rockchip signed boot image",
 					   "rk-image" },
+	[filetype_x86_linux_image] = { "x86 Linux image", "x86-linux" },
 };
 
 static const char *file_type_to_nr_string(enum filetype f)
@@ -435,6 +436,8 @@ enum filetype file_detect_type(const void *_buf, size_t bufsize)
 		return is_dos_exe(buf8) ? filetype_riscv_efi_linux_image : filetype_riscv_linux_image;
 	if (is_riscv_linux_bootimage(buf) && !memcmp(&buf[12], "barebox", 8))
 		return filetype_riscv_barebox_image;
+	if (bufsize > 0x206 && is_x86_linux_bootimage(buf))
+		return filetype_x86_linux_image;
 
 	if (le32_to_cpu(buf[5]) == 0x504d5453)
 		return filetype_mxs_bootstream;
diff --git a/efi/payload/Kconfig b/efi/payload/Kconfig
index a403acc81a93..d0a46704a6b9 100644
--- a/efi/payload/Kconfig
+++ b/efi/payload/Kconfig
@@ -25,4 +25,9 @@ if EFI_PAYLOAD
 config EFI_STUB
 	def_bool HAVE_EFI_STUB
 
+config EFI_HANDOVER_PROTOCOL
+	bool "EFI Handover protocol"
+	default y
+	depends on X86
+
 endif
diff --git a/efi/payload/Makefile b/efi/payload/Makefile
index 1250535302d3..d8b577bf3e23 100644
--- a/efi/payload/Makefile
+++ b/efi/payload/Makefile
@@ -2,6 +2,7 @@
 
 obj-y += init.o
 obj-y += image.o
+obj-$(CONFIG_EFI_HANDOVER_PROTOCOL) += handover.o
 obj-y += efi-initrd.o
 obj-$(CONFIG_OFTREE) += fdt.o
 bbenv-y += env-efi
diff --git a/efi/payload/handover.c b/efi/payload/handover.c
new file mode 100644
index 000000000000..82f4cb4f5286
--- /dev/null
+++ b/efi/payload/handover.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * handover.c - legacy x86 EFI handover protocol
+ *
+ * Copyright (c) 2014 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ */
+
+#define pr_fmt(fmt) "efi-handover: " fmt
+
+#include <clock.h>
+#include <common.h>
+#include <linux/sizes.h>
+#include <linux/ktime.h>
+#include <memory.h>
+#include <command.h>
+#include <magicvar.h>
+#include <init.h>
+#include <driver.h>
+#include <io.h>
+#include <efi.h>
+#include <malloc.h>
+#include <string.h>
+#include <linux/err.h>
+#include <boot.h>
+#include <bootm.h>
+#include <fs.h>
+#include <libfile.h>
+#include <binfmt.h>
+#include <wchar.h>
+#include <efi/efi-payload.h>
+#include <efi/efi-device.h>
+
+#include "image.h"
+#include "setup_header.h"
+
+static int efi_do_execute_image(enum filetype filetype, const char *file)
+{
+	efi_handle_t handle;
+	struct efi_loaded_image *loaded_image;
+	int ret;
+
+	ret = efi_load_image(file, &loaded_image, &handle);
+	if (ret)
+		return ret;
+
+	return efi_execute_image(handle, loaded_image, filetype);
+}
+
+typedef void(*handover_fn)(void *image, struct efi_system_table *table,
+			   struct x86_setup_header *header);
+
+static inline void linux_efi_handover(efi_handle_t handle,
+				      struct x86_setup_header *header)
+{
+	handover_fn handover;
+	uintptr_t addr;
+
+	addr = header->code32_start + header->handover_offset;
+	if (IS_ENABLED(CONFIG_X86_64))
+		addr += 512;
+
+	handover = efi_phys_to_virt(addr);
+	handover(handle, efi_sys_table, header);
+}
+
+static int do_bootm_efi(struct image_data *data)
+{
+	void *tmp;
+	void *initrd = NULL;
+	size_t size;
+	efi_handle_t handle;
+	int ret;
+	const char *options;
+	struct efi_loaded_image *loaded_image;
+	struct x86_setup_header *image_header, *boot_header;
+
+	ret = efi_load_image(data->os_file, &loaded_image, &handle);
+	if (ret)
+		return ret;
+
+	image_header = (struct x86_setup_header *)loaded_image->image_base;
+
+	if (!is_x86_setup_header(image_header) ||
+	    image_header->version < 0x20b ||
+	    !image_header->relocatable_kernel) {
+		pr_err("Not a valid kernel image!\n");
+		BS->unload_image(handle);
+		return -EINVAL;
+	}
+
+	boot_header = xmalloc(0x4000);
+	memset(boot_header, 0, 0x4000);
+	memcpy(boot_header, image_header, sizeof(*image_header));
+
+	/* Refer to Linux kernel commit a27e292b8a54
+	 * ("Documentation/x86/boot: Reserve type_of_loader=13 for barebox")
+	 */
+	boot_header->type_of_loader = 0x13;
+
+	if (data->initrd_file) {
+		tmp = read_file(data->initrd_file, &size);
+		initrd = xmemalign(PAGE_SIZE, PAGE_ALIGN(size));
+		memcpy(initrd, tmp, size);
+		memset(initrd + size, 0, PAGE_ALIGN(size) - size);
+		free(tmp);
+		boot_header->ramdisk_image = efi_virt_to_phys(initrd);
+		boot_header->ramdisk_size = PAGE_ALIGN(size);
+	}
+
+	options = linux_bootargs_get();
+	if (options) {
+		boot_header->cmd_line_ptr = efi_virt_to_phys(options);
+		boot_header->cmdline_size = strlen(options);
+	}
+
+	boot_header->code32_start = efi_virt_to_phys(loaded_image->image_base +
+			(image_header->setup_sects+1) * 512);
+
+	if (bootm_verbose(data)) {
+		printf("\nStarting kernel at 0x%p", loaded_image->image_base);
+		if (data->initrd_file)
+			printf(", initrd at 0x%08x",
+			       boot_header->ramdisk_image);
+		printf("...\n");
+	}
+
+	if (data->dryrun) {
+		BS->unload_image(handle);
+		free(boot_header);
+		free(initrd);
+		return 0;
+	}
+
+	efi_set_variable_usec("LoaderTimeExecUSec", &efi_systemd_vendor_guid,
+			      ktime_to_us(ktime_get()));
+
+	shutdown_barebox();
+	linux_efi_handover(handle, boot_header);
+
+	return 0;
+}
+
+static struct image_handler efi_handle_tr = {
+	.name = "EFI Application",
+	.bootm = do_bootm_efi,
+	.filetype = filetype_exe,
+};
+
+static int efi_register_handover_handler(void)
+{
+	register_image_handler(&efi_handle_tr);
+	return 0;
+}
+late_efi_initcall(efi_register_handover_handler);
diff --git a/efi/payload/image.c b/efi/payload/image.c
index 33c5e18dac27..ae7678188d84 100644
--- a/efi/payload/image.c
+++ b/efi/payload/image.c
@@ -5,13 +5,12 @@
  * Copyright (c) 2014 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
  */
 
+#define pr_fmt(fmt) "efi-image: " fmt
+
 #include <clock.h>
 #include <common.h>
 #include <linux/sizes.h>
-#include <linux/ktime.h>
 #include <memory.h>
-#include <command.h>
-#include <magicvar.h>
 #include <init.h>
 #include <driver.h>
 #include <io.h>
@@ -19,7 +18,7 @@
 #include <malloc.h>
 #include <string.h>
 #include <linux/err.h>
-#include <boot.h>
+#include <bootargs.h>
 #include <bootm.h>
 #include <fs.h>
 #include <libfile.h>
@@ -28,54 +27,8 @@
 #include <efi/efi-payload.h>
 #include <efi/efi-device.h>
 
-struct linux_kernel_header {
-	/* first sector of the image */
-	uint8_t code1[0x0020];
-	uint16_t cl_magic;		/**< Magic number 0xA33F */
-	uint16_t cl_offset;		/**< The offset of command line */
-	uint8_t code2[0x01F1 - 0x0020 - 2 - 2];
-	uint8_t setup_sects;		/**< The size of the setup in sectors */
-	uint16_t root_flags;		/**< If the root is mounted readonly */
-	uint16_t syssize;		/**< obsolete */
-	uint16_t swap_dev;		/**< obsolete */
-	uint16_t ram_size;		/**< obsolete */
-	uint16_t vid_mode;		/**< Video mode control */
-	uint16_t root_dev;		/**< Default root device number */
-	uint16_t boot_flag;		/**< 0xAA55 magic number */
-
-	/* second sector of the image */
-	uint16_t jump;			/**< Jump instruction (this is code!) */
-	uint32_t header;		/**< Magic signature "HdrS" */
-	uint16_t version;		/**< Boot protocol version supported */
-	uint32_t realmode_swtch;	/**< Boot loader hook */
-	uint16_t start_sys;		/**< The load-low segment (obsolete) */
-	uint16_t kernel_version;	/**< Points to kernel version string */
-	uint8_t type_of_loader;		/**< Boot loader identifier */
-	uint8_t loadflags;		/**< Boot protocol option flags */
-	uint16_t setup_move_size;	/**< Move to high memory size */
-	uint32_t code32_start;		/**< Boot loader hook */
-	uint32_t ramdisk_image;		/**< initrd load address */
-	uint32_t ramdisk_size;		/**< initrd size */
-	uint32_t bootsect_kludge;	/**< obsolete */
-	uint16_t heap_end_ptr;		/**< Free memory after setup end */
-	uint8_t ext_loader_ver;		/**< boot loader's extension of the version number */
-	uint8_t ext_loader_type;	/**< boot loader's extension of its type */
-	uint32_t cmd_line_ptr;		/**< Points to the kernel command line */
-	uint32_t initrd_addr_max;	/**< Highest address for initrd */
-	uint32_t kernel_alignment;	/**< Alignment unit required by the kernel */
-	uint8_t relocatable_kernel;	/** */
-	uint8_t min_alignment;		/** */
-	uint16_t xloadflags;		/** */
-	uint32_t cmdline_size;		/** */
-	uint32_t hardware_subarch;	/** */
-	uint64_t hardware_subarch_data;	/** */
-	uint32_t payload_offset;	/** */
-	uint32_t payload_length;	/** */
-	uint64_t setup_data;		/** */
-	uint64_t pref_address;		/** */
-	uint32_t init_size;		/** */
-	uint32_t handover_offset;	/** */
-} __attribute__ ((packed));
+#include "image.h"
+#include "setup_header.h"
 
 static void *efi_read_file(const char *file, size_t *size)
 {
@@ -85,10 +38,6 @@ static void *efi_read_file(const char *file, size_t *size)
 	char *buf;
 	ssize_t ret;
 
-	buf = read_file(file, size);
-	if (buf || errno != ENOMEM)
-		return buf;
-
 	ret = stat(file, &s);
 	if (ret)
 		return NULL;
@@ -122,8 +71,8 @@ static void efi_free_file(void *_mem, size_t size)
 		BS->free_pages(mem, DIV_ROUND_UP(size, EFI_PAGE_SIZE));
 }
 
-static int efi_load_image(const char *file, struct efi_loaded_image **loaded_image,
-		efi_handle_t *h)
+int efi_load_image(const char *file, struct efi_loaded_image **loaded_image,
+		   efi_handle_t *h)
 {
 	void *exe;
 	size_t size;
@@ -158,10 +107,7 @@ static int efi_load_image(const char *file, struct efi_loaded_image **loaded_ima
 
 static bool is_linux_image(enum filetype filetype, const void *base)
 {
-	const struct linux_kernel_header *hdr = base;
-
-	if (IS_ENABLED(CONFIG_X86) &&
-	    hdr->boot_flag == 0xAA55 && hdr->header == 0x53726448)
+	if (IS_ENABLED(CONFIG_X86) && is_x86_setup_header(base))
 		return true;
 
 	if (IS_ENABLED(CONFIG_ARM64) &&
@@ -171,18 +117,13 @@ static bool is_linux_image(enum filetype filetype, const void *base)
 	return false;
 }
 
-static int efi_execute_image(enum filetype filetype, const char *file)
+int efi_execute_image(efi_handle_t handle,
+		      struct efi_loaded_image *loaded_image,
+		      enum filetype filetype)
 {
-	efi_handle_t handle;
-	struct efi_loaded_image *loaded_image;
 	efi_status_t efiret;
 	const char *options;
 	bool is_driver;
-	int ret;
-
-	ret = efi_load_image(file, &loaded_image, &handle);
-	if (ret)
-		return ret;
 
 	is_driver = (loaded_image->image_code_type == EFI_BOOT_SERVICES_CODE) ||
 		(loaded_image->image_code_type == EFI_RUNTIME_SERVICES_CODE);
@@ -216,110 +157,17 @@ static int efi_execute_image(enum filetype filetype, const char *file)
 	return -efi_errno(efiret);
 }
 
-typedef void(*handover_fn)(void *image, struct efi_system_table *table,
-		struct linux_kernel_header *header);
-
-static inline void linux_efi_handover(efi_handle_t handle,
-		struct linux_kernel_header *header)
-{
-	handover_fn handover;
-	uintptr_t addr;
-
-	addr = header->code32_start + header->handover_offset;
-	if (IS_ENABLED(CONFIG_X86_64))
-		addr += 512;
-
-	handover = efi_phys_to_virt(addr);
-	handover(handle, efi_sys_table, header);
-}
-
-static int do_bootm_efi(struct image_data *data)
+static int efi_execute(struct binfmt_hook *b, char *file, int argc, char **argv)
 {
-	void *tmp;
-	void *initrd = NULL;
-	size_t size;
+	struct efi_loaded_image *loaded_image;
 	efi_handle_t handle;
 	int ret;
-	const char *options;
-	struct efi_loaded_image *loaded_image;
-	struct linux_kernel_header *image_header, *boot_header;
 
-	ret = efi_load_image(data->os_file, &loaded_image, &handle);
+	ret = efi_load_image(file, &loaded_image, &handle);
 	if (ret)
 		return ret;
 
-	image_header = (struct linux_kernel_header *)loaded_image->image_base;
-
-	if (image_header->boot_flag != 0xAA55 ||
-	    image_header->header != 0x53726448 ||
-	    image_header->version < 0x20b ||
-	    !image_header->relocatable_kernel) {
-		pr_err("Not a valid kernel image!\n");
-		BS->unload_image(handle);
-		return -EINVAL;
-	}
-
-	boot_header = xmalloc(0x4000);
-	memset(boot_header, 0, 0x4000);
-	memcpy(boot_header, image_header, sizeof(*image_header));
-
-	/* Refer to Linux kernel commit a27e292b8a54
-	 * ("Documentation/x86/boot: Reserve type_of_loader=13 for barebox")
-	 */
-	boot_header->type_of_loader = 0x13;
-
-	if (data->initrd_file) {
-		tmp = read_file(data->initrd_file, &size);
-		initrd = xmemalign(PAGE_SIZE, PAGE_ALIGN(size));
-		memcpy(initrd, tmp, size);
-		memset(initrd + size, 0, PAGE_ALIGN(size) - size);
-		free(tmp);
-		boot_header->ramdisk_image = efi_virt_to_phys(initrd);
-		boot_header->ramdisk_size = PAGE_ALIGN(size);
-	}
-
-	options = linux_bootargs_get();
-	if (options) {
-		boot_header->cmd_line_ptr = efi_virt_to_phys(options);
-		boot_header->cmdline_size = strlen(options);
-	}
-
-	boot_header->code32_start = efi_virt_to_phys(loaded_image->image_base +
-			(image_header->setup_sects+1) * 512);
-
-	if (bootm_verbose(data)) {
-		printf("\nStarting kernel at 0x%p", loaded_image->image_base);
-		if (data->initrd_file)
-			printf(", initrd at 0x%08x",
-			       boot_header->ramdisk_image);
-		printf("...\n");
-	}
-
-	if (data->dryrun) {
-		BS->unload_image(handle);
-		free(boot_header);
-		free(initrd);
-		return 0;
-	}
-
-	efi_set_variable_usec("LoaderTimeExecUSec", &efi_systemd_vendor_guid,
-			      ktime_to_us(ktime_get()));
-
-	shutdown_barebox();
-	linux_efi_handover(handle, boot_header);
-
-	return 0;
-}
-
-static struct image_handler efi_handle_tr = {
-	.name = "EFI Application",
-	.bootm = do_bootm_efi,
-	.filetype = filetype_exe,
-};
-
-static int efi_execute(struct binfmt_hook *b, char *file, int argc, char **argv)
-{
-	return efi_execute_image(b->type, file);
+	return efi_execute_image(handle, loaded_image, b->type);
 }
 
 static struct binfmt_hook binfmt_efi_hook = {
@@ -352,13 +200,19 @@ static struct binfmt_hook binfmt_arm64_efi_hook = {
 	.hook = efi_execute,
 };
 
+static struct binfmt_hook binfmt_x86_efi_hook = {
+	.type = filetype_x86_linux_image,
+	.hook = efi_execute,
+};
+
 static int efi_register_image_handler(void)
 {
-	register_image_handler(&efi_handle_tr);
 	binfmt_register(&binfmt_efi_hook);
 
-	if (IS_ENABLED(CONFIG_X86))
+	if (IS_ENABLED(CONFIG_X86)) {
 		register_image_handler(&non_efi_handle_linux_x86);
+		binfmt_register(&binfmt_x86_efi_hook);
+	}
 
 	if (IS_ENABLED(CONFIG_ARM64))
 		binfmt_register(&binfmt_arm64_efi_hook);
diff --git a/efi/payload/image.h b/efi/payload/image.h
new file mode 100644
index 000000000000..673b21db839a
--- /dev/null
+++ b/efi/payload/image.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __EFI_PAYLOAD_IMAGE_H__
+#define __EFI_PAYLOAD_IMAGE_H__
+
+#include <efi/types.h>
+
+int efi_load_image(const char *file, struct efi_loaded_image **loaded_image,
+		   efi_handle_t *h);
+
+int efi_execute_image(efi_handle_t handle,
+		      struct efi_loaded_image *loaded_image,
+		      enum filetype filetype);
+
+#endif
diff --git a/efi/payload/setup_header.h b/efi/payload/setup_header.h
new file mode 100644
index 000000000000..4f094b844415
--- /dev/null
+++ b/efi/payload/setup_header.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __EFI_PAYLOAD_SETUP_HEADER_H__
+#define __EFI_PAYLOAD_SETUP_HEADER_H__
+
+#include <linux/types.h>
+
+struct x86_setup_header {
+	/* first sector of the image */
+	uint8_t code1[0x0020];
+	uint16_t cl_magic;		/**< Magic number 0xA33F */
+	uint16_t cl_offset;		/**< The offset of command line */
+	uint8_t code2[0x01F1 - 0x0020 - 2 - 2];
+	uint8_t setup_sects;		/**< The size of the setup in sectors */
+	uint16_t root_flags;		/**< If the root is mounted readonly */
+	uint16_t syssize;		/**< obsolete */
+	uint16_t swap_dev;		/**< obsolete */
+	uint16_t ram_size;		/**< obsolete */
+	uint16_t vid_mode;		/**< Video mode control */
+	uint16_t root_dev;		/**< Default root device number */
+	uint16_t boot_flag;		/**< 0xAA55 magic number */
+
+	/* second sector of the image */
+	uint16_t jump;			/**< Jump instruction (this is code!) */
+	uint32_t header;		/**< Magic signature "HdrS" */
+	uint16_t version;		/**< Boot protocol version supported */
+	uint32_t realmode_swtch;	/**< Boot loader hook */
+	uint16_t start_sys;		/**< The load-low segment (obsolete) */
+	uint16_t kernel_version;	/**< Points to kernel version string */
+	uint8_t type_of_loader;		/**< Boot loader identifier */
+	uint8_t loadflags;		/**< Boot protocol option flags */
+	uint16_t setup_move_size;	/**< Move to high memory size */
+	uint32_t code32_start;		/**< Boot loader hook */
+	uint32_t ramdisk_image;		/**< initrd load address */
+	uint32_t ramdisk_size;		/**< initrd size */
+	uint32_t bootsect_kludge;	/**< obsolete */
+	uint16_t heap_end_ptr;		/**< Free memory after setup end */
+	uint8_t ext_loader_ver;		/**< boot loader's extension of the version number */
+	uint8_t ext_loader_type;	/**< boot loader's extension of its type */
+	uint32_t cmd_line_ptr;		/**< Points to the kernel command line */
+	uint32_t initrd_addr_max;	/**< Highest address for initrd */
+	uint32_t kernel_alignment;	/**< Alignment unit required by the kernel */
+	uint8_t relocatable_kernel;	/** */
+	uint8_t min_alignment;		/** */
+	uint16_t xloadflags;		/** */
+	uint32_t cmdline_size;		/** */
+	uint32_t hardware_subarch;	/** */
+	uint64_t hardware_subarch_data;	/** */
+	uint32_t payload_offset;	/** */
+	uint32_t payload_length;	/** */
+	uint64_t setup_data;		/** */
+	uint64_t pref_address;		/** */
+	uint32_t init_size;		/** */
+	uint32_t handover_offset;	/** */
+} __attribute__ ((packed));
+
+static inline bool is_x86_setup_header(const void *base)
+{
+	const struct x86_setup_header *hdr = base;
+
+	return hdr->boot_flag == 0xAA55 && hdr->header == 0x53726448;
+}
+
+#endif
diff --git a/include/filetype.h b/include/filetype.h
index 6f4a103df304..ff4d54ee3c45 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -67,6 +67,7 @@ enum filetype {
 	filetype_nxp_fspi_image,
 	filetype_zstd_compressed,
 	filetype_rockchip_rkss_image,
+	filetype_x86_linux_image,
 	filetype_max,
 };
 
@@ -150,4 +151,9 @@ static inline bool is_riscv_linux_bootimage(const void *header)
 	return le32_to_cpup(header + 56) == 0x05435352;
 }
 
+static inline bool is_x86_linux_bootimage(const void *header)
+{
+	return le32_to_cpup(header + 0x202) == 0x53726448;
+}
+
 #endif /* __FILE_TYPE_H */
-- 
2.34.1