Merge tag 'stable-shared-branch-for-driver-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into driver-core-next

Ard writes:

Stable shared branch between EFI and driver tree

Stable shared branch to ease the integration of Hans's series to support
device firmware loaded from EFI boot service memory regions.

[PATCH v12 00/10] efi/firmware/platform-x86: Add EFI embedded fw support
https://lore.kernel.org/linux-efi/[e-mail]/

* tag 'stable-shared-branch-for-driver-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi: Add embedded peripheral firmware support
efi: Export boot-services code and data as debugfs-blobs

arch/x86/platform/efi/efi.c

···
 	     efi.memmap.desc_version);
 
 	memblock_reserve(pmap, efi.memmap.nr_map * efi.memmap.desc_size);
+	set_bit(EFI_PRESERVE_BS_REGIONS, &efi.flags);
 
 	return 0;
 }
···
 		goto err;
 	}
 
+	efi_check_for_embedded_firmwares();
 	efi_free_boot_services();
 
 	/*

arch/x86/platform/efi/quirks.c

···
 	int num_entries = 0;
 	void *new, *new_md;
 
+	/* Keep all regions for /sys/kernel/debug/efi */
+	if (efi_enabled(EFI_DBG))
+		return;
+
 	for_each_efi_memory_desc(md) {
 		unsigned long long start = md->phys_addr;
 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;

drivers/firmware/efi/Kconfig

···
 
 endmenu
 
+config EFI_EMBEDDED_FIRMWARE
+	bool
+	depends on EFI
+	select CRYPTO_LIB_SHA256
+
 config UEFI_CPER
 	bool
 

drivers/firmware/efi/Makefile

···
 obj-$(CONFIG_EFI_DEV_PATH_PARSER)	+= dev-path-parser.o
 obj-$(CONFIG_APPLE_PROPERTIES)		+= apple-properties.o
 obj-$(CONFIG_EFI_RCI2_TABLE)		+= rci2-table.o
+obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE)	+= embedded-firmware.o
 
 fake_map-y				+= fake_mem.o
 fake_map-$(CONFIG_X86)			+= x86_fake_mem.o

drivers/firmware/efi/efi.c

···
 #include <linux/kobject.h>
 #include <linux/module.h>
 #include <linux/init.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/efi.h>
 #include <linux/of.h>
···
 static inline int efivar_ssdt_load(void) { return 0; }
 #endif
 
+#ifdef CONFIG_DEBUG_FS
+
+#define EFI_DEBUGFS_MAX_BLOBS 32
+
+static struct debugfs_blob_wrapper debugfs_blob[EFI_DEBUGFS_MAX_BLOBS];
+
+static void __init efi_debugfs_init(void)
+{
+	struct dentry *efi_debugfs;
+	efi_memory_desc_t *md;
+	char name[32];
+	int type_count[EFI_BOOT_SERVICES_DATA + 1] = {};
+	int i = 0;
+
+	efi_debugfs = debugfs_create_dir("efi", NULL);
+	if (IS_ERR_OR_NULL(efi_debugfs))
+		return;
+
+	for_each_efi_memory_desc(md) {
+		switch (md->type) {
+		case EFI_BOOT_SERVICES_CODE:
+			snprintf(name, sizeof(name), "boot_services_code%d",
+				 type_count[md->type]++);
+			break;
+		case EFI_BOOT_SERVICES_DATA:
+			snprintf(name, sizeof(name), "boot_services_data%d",
+				 type_count[md->type]++);
+			break;
+		default:
+			continue;
+		}
+
+		if (i >= EFI_DEBUGFS_MAX_BLOBS) {
+			pr_warn("More then %d EFI boot service segments, only showing first %d in debugfs\n",
+				EFI_DEBUGFS_MAX_BLOBS, EFI_DEBUGFS_MAX_BLOBS);
+			break;
+		}
+
+		debugfs_blob[i].size = md->num_pages << EFI_PAGE_SHIFT;
+		debugfs_blob[i].data = memremap(md->phys_addr,
+						debugfs_blob[i].size,
+						MEMREMAP_WB);
+		if (!debugfs_blob[i].data)
+			continue;
+
+		debugfs_create_blob(name, 0400, efi_debugfs, &debugfs_blob[i]);
+		i++;
+	}
+}
+#else
+static inline void efi_debugfs_init(void) {}
+#endif
+
 /*
  * We register the efi subsystem with the firmware subsystem and the
  * efivars subsystem with the efi subsystem, if the system was booted with
···
 		pr_err("efivars: Subsystem registration failed.\n");
 		goto err_remove_group;
 	}
+
+	if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS))
+		efi_debugfs_init();
 
 	return 0;
 

drivers/firmware/efi/embedded-firmware.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for extracting embedded firmware for peripherals from EFI code,
+ *
+ * Copyright (c) 2018 Hans de Goede <[e-mail]>
+ */
+
+#include <linux/dmi.h>
+#include <linux/efi.h>
+#include <linux/efi_embedded_fw.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <crypto/sha.h>
+
+/* Exported for use by lib/test_firmware.c only */
+LIST_HEAD(efi_embedded_fw_list);
+EXPORT_SYMBOL_GPL(efi_embedded_fw_list);
+
+static bool checked_for_fw;
+
+static const struct dmi_system_id * const embedded_fw_table[] = {
+	NULL
+};
+
+/*
+ * Note the efi_check_for_embedded_firmwares() code currently makes the
+ * following 2 assumptions. This may needs to be revisited if embedded firmware
+ * is found where this is not true:
+ * 1) The firmware is only found in EFI_BOOT_SERVICES_CODE memory segments
+ * 2) The firmware always starts at an offset which is a multiple of 8 bytes
+ */
+static int __init efi_check_md_for_embedded_firmware(
+	efi_memory_desc_t *md, const struct efi_embedded_fw_desc *desc)
+{
+	struct sha256_state sctx;
+	struct efi_embedded_fw *fw;
+	u8 sha256[32];
+	u64 i, size;
+	u8 *map;
+
+	size = md->num_pages << EFI_PAGE_SHIFT;
+	map = memremap(md->phys_addr, size, MEMREMAP_WB);
+	if (!map) {
+		pr_err("Error mapping EFI mem at %#llx\n", md->phys_addr);
+		return -ENOMEM;
+	}
+
+	for (i = 0; (i + desc->length) <= size; i += 8) {
+		if (memcmp(map + i, desc->prefix, EFI_EMBEDDED_FW_PREFIX_LEN))
+			continue;
+
+		sha256_init(&sctx);
+		sha256_update(&sctx, map + i, desc->length);
+		sha256_final(&sctx, sha256);
+		if (memcmp(sha256, desc->sha256, 32) == 0)
+			break;
+	}
+	if ((i + desc->length) > size) {
+		memunmap(map);
+		return -ENOENT;
+	}
+
+	pr_info("Found EFI embedded fw '%s'\n", desc->name);
+
+	fw = kmalloc(sizeof(*fw), GFP_KERNEL);
+	if (!fw) {
+		memunmap(map);
+		return -ENOMEM;
+	}
+
+	fw->data = kmemdup(map + i, desc->length, GFP_KERNEL);
+	memunmap(map);
+	if (!fw->data) {
+		kfree(fw);
+		return -ENOMEM;
+	}
+
+	fw->name = desc->name;
+	fw->length = desc->length;
+	list_add(&fw->list, &efi_embedded_fw_list);
+
+	return 0;
+}
+
+void __init efi_check_for_embedded_firmwares(void)
+{
+	const struct efi_embedded_fw_desc *fw_desc;
+	const struct dmi_system_id *dmi_id;
+	efi_memory_desc_t *md;
+	int i, r;
+
+	for (i = 0; embedded_fw_table[i]; i++) {
+		dmi_id = dmi_first_match(embedded_fw_table[i]);
+		if (!dmi_id)
+			continue;
+
+		fw_desc = dmi_id->driver_data;
+
+		/*
+		 * In some drivers the struct driver_data contains may contain
+		 * other driver specific data after the fw_desc struct; and
+		 * the fw_desc struct itself may be empty, skip these.
+		 */
+		if (!fw_desc->name)
+			continue;
+
+		for_each_efi_memory_desc(md) {
+			if (md->type != EFI_BOOT_SERVICES_CODE)
+				continue;
+
+			r = efi_check_md_for_embedded_firmware(md, fw_desc);
+			if (r == 0)
+				break;
+		}
+	}
+
+	checked_for_fw = true;
+}
+
+int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size)
+{
+	struct efi_embedded_fw *iter, *fw = NULL;
+
+	if (!checked_for_fw) {
+		pr_warn("Warning %s called while we did not check for embedded fw\n",
+			__func__);
+		return -ENOENT;
+	}
+
+	list_for_each_entry(iter, &efi_embedded_fw_list, list) {
+		if (strcmp(name, iter->name) == 0) {
+			fw = iter;
+			break;
+		}
+	}
+
+	if (!fw)
+		return -ENOENT;
+
+	*data = fw->data;
+	*size = fw->length;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(efi_get_embedded_fw);

include/linux/efi.h

···
 #define EFI_NX_PE_DATA		9	/* Can runtime data regions be mapped non-executable? */
 #define EFI_MEM_ATTR		10	/* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */
 #define EFI_MEM_NO_SOFT_RESERVE	11	/* Is the kernel configured to ignore soft reservations? */
+#define EFI_PRESERVE_BS_REGIONS	12	/* Are EFI boot-services memory segments available? */
 
 #ifdef CONFIG_EFI
 /*
···
 #else
 static inline void
 efi_enable_reset_attack_mitigation(void) { }
+#endif
+
+#ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
+void efi_check_for_embedded_firmwares(void);
+#else
+static inline void efi_check_for_embedded_firmwares(void) { }
 #endif
 
 efi_status_t efi_random_get_seed(void);

include/linux/efi_embedded_fw.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_EFI_EMBEDDED_FW_H
+#define _LINUX_EFI_EMBEDDED_FW_H
+
+#include <linux/list.h>
+#include <linux/mod_devicetable.h>
+
+#define EFI_EMBEDDED_FW_PREFIX_LEN		8
+
+/*
+ * This struct and efi_embedded_fw_list are private to the efi-embedded fw
+ * implementation they are in this header for use by lib/test_firmware.c only!
+ */
+struct efi_embedded_fw {
+	struct list_head list;
+	const char *name;
+	const u8 *data;
+	size_t length;
+};
+
+extern struct list_head efi_embedded_fw_list;
+
+/**
+ * struct efi_embedded_fw_desc - This struct is used by the EFI embedded-fw
+ *                               code to search for embedded firmwares.
+ *
+ * @name:   Name to register the firmware with if found
+ * @prefix: First 8 bytes of the firmware
+ * @length: Length of the firmware in bytes including prefix
+ * @sha256: SHA256 of the firmware
+ */
+struct efi_embedded_fw_desc {
+	const char *name;
+	u8 prefix[EFI_EMBEDDED_FW_PREFIX_LEN];
+	u32 length;
+	u8 sha256[32];
+};
+
+int efi_get_embedded_fw(const char *name, const u8 **dat, size_t *sz);
+
+#endif