EFI updates for v6.4:

- relocate the LoongArch kernel if the preferred address is already
   occupied;
 
 - implement BTI annotations for arm64 EFI stub and zboot images;
 
 - clean up arm64 zboot Kbuild rules for injecting the kernel code size.
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Merge tag 'efi-next-for-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI updates from Ard Biesheuvel:

 - relocate the LoongArch kernel if the preferred address is already
   occupied

 - implement BTI annotations for arm64 EFI stub and zboot images

 - clean up arm64 zboot Kbuild rules for injecting the kernel code size

* tag 'efi-next-for-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/zboot: arm64: Grab code size from ELF symbol in payload
  efi/zboot: arm64: Inject kernel code size symbol into the zboot payload
  efi/zboot: Set forward edge CFI compat header flag if supported
  efi/zboot: Add BSS padding before compression
  arm64: efi: Enable BTI codegen and add PE/COFF annotation
  efi/pe: Import new BTI/IBT header flags from the spec
  efi/loongarch: Reintroduce efi_relocate_kernel() to relocate kernel

arch/arm64/boot/Makefile

@@ -42,5 +42,9 @@ $(obj)/Image.zst: $(obj)/Image FORCE
 EFI_ZBOOT_PAYLOAD	:= Image
 EFI_ZBOOT_BFD_TARGET	:= elf64-littleaarch64
 EFI_ZBOOT_MACH_TYPE	:= ARM64
+EFI_ZBOOT_FORWARD_CFI	:= $(CONFIG_ARM64_BTI_KERNEL)
+
+EFI_ZBOOT_OBJCOPY_FLAGS	= --add-symbol zboot_code_size=0x$(shell \
+				$(NM) vmlinux|grep _kernel_codesize|cut -d' ' -f1)
 
 include $(srctree)/drivers/firmware/efi/libstub/Makefile.zboot

arch/arm64/kernel/efi-header.S

@@ -81,9 +81,47 @@
 	.quad	0					// CertificationTable
 	.quad	0					// BaseRelocationTable
 
-#ifdef CONFIG_DEBUG_EFI
+#if defined(CONFIG_DEBUG_EFI) || defined(CONFIG_ARM64_BTI_KERNEL)
 	.long	.Lefi_debug_table - .L_head		// DebugTable
 	.long	.Lefi_debug_table_size
+
+	/*
+	 * The debug table is referenced via its Relative Virtual Address (RVA),
+	 * which is only defined for those parts of the image that are covered
+	 * by a section declaration. Since this header is not covered by any
+	 * section, the debug table must be emitted elsewhere. So stick it in
+	 * the .init.rodata section instead.
+	 *
+	 * Note that the payloads themselves are permitted to have zero RVAs,
+	 * which means we can simply put those right after the section headers.
+	 */
+	__INITRODATA
+
+	.align	2
+.Lefi_debug_table:
+#ifdef CONFIG_DEBUG_EFI
+	// EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
+	.long	0					// Characteristics
+	.long	0					// TimeDateStamp
+	.short	0					// MajorVersion
+	.short	0					// MinorVersion
+	.long	IMAGE_DEBUG_TYPE_CODEVIEW		// Type
+	.long	.Lefi_debug_entry_size			// SizeOfData
+	.long	0					// RVA
+	.long	.Lefi_debug_entry - .L_head		// FileOffset
+#endif
+#ifdef CONFIG_ARM64_BTI_KERNEL
+	.long	0					// Characteristics
+	.long	0					// TimeDateStamp
+	.short	0					// MajorVersion
+	.short	0					// MinorVersion
+	.long	IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS	// Type
+	.long	4					// SizeOfData
+	.long	0					// RVA
+	.long	.Lefi_dll_characteristics_ex - .L_head	// FileOffset
+#endif
+	.set	.Lefi_debug_table_size, . - .Lefi_debug_table
+	.previous
 #endif
 
 	// Section table
@@ -119,33 +157,6 @@
 	.set	.Lsection_count, (. - .Lsection_table) / 40
 
 #ifdef CONFIG_DEBUG_EFI
-	/*
-	 * The debug table is referenced via its Relative Virtual Address (RVA),
-	 * which is only defined for those parts of the image that are covered
-	 * by a section declaration. Since this header is not covered by any
-	 * section, the debug table must be emitted elsewhere. So stick it in
-	 * the .init.rodata section instead.
-	 *
-	 * Note that the EFI debug entry itself may legally have a zero RVA,
-	 * which means we can simply put it right after the section headers.
-	 */
-	__INITRODATA
-
-	.align	2
-.Lefi_debug_table:
-	// EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
-	.long	0					// Characteristics
-	.long	0					// TimeDateStamp
-	.short	0					// MajorVersion
-	.short	0					// MinorVersion
-	.long	IMAGE_DEBUG_TYPE_CODEVIEW		// Type
-	.long	.Lefi_debug_entry_size			// SizeOfData
-	.long	0					// RVA
-	.long	.Lefi_debug_entry - .L_head		// FileOffset
-
-	.set	.Lefi_debug_table_size, . - .Lefi_debug_table
-	.previous
-
 .Lefi_debug_entry:
 	// EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
 	.ascii	"NB10"					// Signature
@@ -157,6 +168,10 @@
 
 	.set	.Lefi_debug_entry_size, . - .Lefi_debug_entry
 #endif
+#ifdef CONFIG_ARM64_BTI_KERNEL
+.Lefi_dll_characteristics_ex:
+	.long	IMAGE_DLLCHARACTERISTICS_EX_FORWARD_CFI_COMPAT
+#endif
 
 	.balign	SEGMENT_ALIGN
 .Lefi_header_end:

arch/arm64/kernel/image-vars.h

@@ -108,4 +108,8 @@ KVM_NVHE_ALIAS(kvm_protected_mode_initialized);
 
 #endif /* CONFIG_KVM */
 
+#ifdef CONFIG_EFI_ZBOOT
+_kernel_codesize = ABSOLUTE(__inittext_end - _text);
+#endif
+
 #endif /* __ARM64_KERNEL_IMAGE_VARS_H */

drivers/firmware/efi/libstub/Makefile

@@ -23,8 +23,7 @@ cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ \
 # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
 # disable the stackleak plugin
 cflags-$(CONFIG_ARM64)		+= -fpie $(DISABLE_STACKLEAK_PLUGIN) \
-				   -fno-unwind-tables -fno-asynchronous-unwind-tables \
+				   -fno-unwind-tables -fno-asynchronous-unwind-tables
-				   $(call cc-option,-mbranch-protection=none)
 cflags-$(CONFIG_ARM)		+= -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \
 				   -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \
 				   -DEFI_HAVE_STRCMP -fno-builtin -fpic \

drivers/firmware/efi/libstub/Makefile.zboot

@@ -1,7 +1,16 @@
 # SPDX-License-Identifier: GPL-2.0
 
 # to be include'd by arch/$(ARCH)/boot/Makefile after setting
-# EFI_ZBOOT_PAYLOAD, EFI_ZBOOT_BFD_TARGET and EFI_ZBOOT_MACH_TYPE
+# EFI_ZBOOT_PAYLOAD, EFI_ZBOOT_BFD_TARGET, EFI_ZBOOT_MACH_TYPE and
+# EFI_ZBOOT_FORWARD_CFI
+
+quiet_cmd_copy_and_pad = PAD     $@
+      cmd_copy_and_pad = cp $< $@ && \
+			 truncate -s $(shell hexdump -s16 -n4 -e '"%u"' $<) $@
+
+# Pad the file to the size of the uncompressed image in memory, including BSS
+$(obj)/vmlinux.bin: $(obj)/$(EFI_ZBOOT_PAYLOAD) FORCE
+	$(call if_changed,copy_and_pad)
 
 comp-type-$(CONFIG_KERNEL_GZIP)		:= gzip
 comp-type-$(CONFIG_KERNEL_LZ4)		:= lz4
@@ -10,26 +19,32 @@ comp-type-$(CONFIG_KERNEL_LZO)		:= lzo
 comp-type-$(CONFIG_KERNEL_XZ)		:= xzkern
 comp-type-$(CONFIG_KERNEL_ZSTD)		:= zstd22
 
-# Copy the SizeOfHeaders, SizeOfCode and SizeOfImage fields from the payload to
+# in GZIP, the appended le32 carrying the uncompressed size is part of the
-# the end of the compressed image. Note that this presupposes a PE header
+# format, but in other cases, we just append it at the end for convenience,
-# offset of 64 bytes, which is what arm64, RISC-V and LoongArch use.
+# causing the original tools to complain when checking image integrity.
-quiet_cmd_compwithsize = $(quiet_cmd_$(comp-type-y))
+# So disregard it when calculating the payload size in the zimage header.
-      cmd_compwithsize = $(cmd_$(comp-type-y)) && ( \
+zboot-method-y                         := $(comp-type-y)_with_size
-			   dd status=none if=$< bs=4 count=1 skip=37 ; \
+zboot-size-len-y                       := 4
-			   dd status=none if=$< bs=4 count=1 skip=23 ; \
-			   dd status=none if=$< bs=4 count=1 skip=36 ) >> $@
 
-$(obj)/vmlinuz: $(obj)/$(EFI_ZBOOT_PAYLOAD) FORCE
+zboot-method-$(CONFIG_KERNEL_GZIP)     := gzip
-	$(call if_changed,compwithsize)
+zboot-size-len-$(CONFIG_KERNEL_GZIP)   := 0
 
-OBJCOPYFLAGS_vmlinuz.o := -I binary -O $(EFI_ZBOOT_BFD_TARGET) \
+$(obj)/vmlinuz: $(obj)/vmlinux.bin FORCE
+	$(call if_changed,$(zboot-method-y))
+
+OBJCOPYFLAGS_vmlinuz.o := -I binary -O $(EFI_ZBOOT_BFD_TARGET) $(EFI_ZBOOT_OBJCOPY_FLAGS) \
 			  --rename-section .data=.gzdata,load,alloc,readonly,contents
 $(obj)/vmlinuz.o: $(obj)/vmlinuz FORCE
 	$(call if_changed,objcopy)
 
+aflags-zboot-header-$(EFI_ZBOOT_FORWARD_CFI) := \
+		-DPE_DLL_CHAR_EX=IMAGE_DLLCHARACTERISTICS_EX_FORWARD_CFI_COMPAT
+
 AFLAGS_zboot-header.o += -DMACHINE_TYPE=IMAGE_FILE_MACHINE_$(EFI_ZBOOT_MACH_TYPE) \
 			 -DZBOOT_EFI_PATH="\"$(realpath $(obj)/vmlinuz.efi.elf)\"" \
-			 -DCOMP_TYPE="\"$(comp-type-y)\""
+			 -DZBOOT_SIZE_LEN=$(zboot-size-len-y) \
+			 -DCOMP_TYPE="\"$(comp-type-y)\"" \
+			 $(aflags-zboot-header-y)
 
 $(obj)/zboot-header.o: $(srctree)/drivers/firmware/efi/libstub/zboot-header.S FORCE
 	$(call if_changed_rule,as_o_S)
@@ -44,4 +59,4 @@ OBJCOPYFLAGS_vmlinuz.efi := -O binary
 $(obj)/vmlinuz.efi: $(obj)/vmlinuz.efi.elf FORCE
 	$(call if_changed,objcopy)
 
-targets += zboot-header.o vmlinuz vmlinuz.o vmlinuz.efi.elf vmlinuz.efi
+targets += zboot-header.o vmlinux.bin vmlinuz vmlinuz.o vmlinuz.efi.elf vmlinuz.efi

drivers/firmware/efi/libstub/arm64.c

@@ -9,6 +9,7 @@
 
 #include <linux/efi.h>
 #include <asm/efi.h>
+#include <asm/image.h>
 #include <asm/memory.h>
 #include <asm/sysreg.h>
 
@@ -88,9 +89,10 @@ efi_status_t check_platform_features(void)
 #define DCTYPE	"cvau"
 #endif
 
+u32 __weak code_size;
+
 void efi_cache_sync_image(unsigned long image_base,
-			  unsigned long alloc_size,
+			  unsigned long alloc_size)
-			  unsigned long code_size)
 {
 	u32 ctr = read_cpuid_effective_cachetype();
 	u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
@@ -98,16 +100,21 @@ void efi_cache_sync_image(unsigned long image_base,
 
 	/* only perform the cache maintenance if needed for I/D coherency */
 	if (!(ctr & BIT(CTR_EL0_IDC_SHIFT))) {
+		unsigned long base = image_base;
+		unsigned long size = code_size;
+
 		do {
-			asm("dc " DCTYPE ", %0" :: "r"(image_base));
+			asm("dc " DCTYPE ", %0" :: "r"(base));
-			image_base += lsize;
+			base += lsize;
-			code_size -= lsize;
+			size -= lsize;
-		} while (code_size >= lsize);
+		} while (size >= lsize);
 	}
 
 	asm("ic ialluis");
 	dsb(ish);
 	isb();
+
+	efi_remap_image(image_base, alloc_size, code_size);
 }
 
 unsigned long __weak primary_entry_offset(void)

drivers/firmware/efi/libstub/efistub.h

@@ -1066,8 +1066,7 @@ struct screen_info *__alloc_screen_info(void);
 void free_screen_info(struct screen_info *si);
 
 void efi_cache_sync_image(unsigned long image_base,
-			  unsigned long alloc_size,
+			  unsigned long alloc_size);
-			  unsigned long code_size);
 
 struct efi_smbios_record {
 	u8	type;

drivers/firmware/efi/libstub/loongarch-stub.c

@@ -21,27 +21,17 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 efi_loaded_image_t *image,
 				 efi_handle_t image_handle)
 {
-	int nr_pages = round_up(kernel_asize, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
-	efi_physical_addr_t kernel_addr = EFI_KIMG_PREFERRED_ADDRESS;
 	efi_status_t status;
+	unsigned long kernel_addr = 0;
 
-	/*
+	kernel_addr = (unsigned long)&kernel_offset - kernel_offset;
-	 * Allocate space for the kernel image at the preferred offset. This is
-	 * the only location in memory from where we can execute the image, so
-	 * no point in falling back to another allocation.
-	 */
-	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
-			     EFI_LOADER_DATA, nr_pages, &kernel_addr);
-	if (status != EFI_SUCCESS)
-		return status;
 
-	*image_addr = EFI_KIMG_PREFERRED_ADDRESS;
+	status = efi_relocate_kernel(&kernel_addr, kernel_fsize, kernel_asize,
+		     EFI_KIMG_PREFERRED_ADDRESS, efi_get_kimg_min_align(), 0x0);
+
+	*image_addr = kernel_addr;
 	*image_size = kernel_asize;
 
-	memcpy((void *)EFI_KIMG_PREFERRED_ADDRESS,
-	       (void *)&kernel_offset - kernel_offset,
-	       kernel_fsize);
-
 	return status;
 }
 

drivers/firmware/efi/libstub/zboot-header.S

@@ -17,7 +17,7 @@ __efistub_efi_zboot_header:
 	.long		MZ_MAGIC
 	.ascii		"zimg"					// image type
 	.long		__efistub__gzdata_start - .Ldoshdr	// payload offset
-	.long		__efistub__gzdata_size - 12		// payload size
+	.long		__efistub__gzdata_size - ZBOOT_SIZE_LEN	// payload size
 	.long		0, 0					// reserved
 	.asciz		COMP_TYPE				// compression type
 	.org		.Ldoshdr + 0x38
@@ -78,9 +78,36 @@ __efistub_efi_zboot_header:
 	.quad		0				// ExceptionTable
 	.quad		0				// CertificationTable
 	.quad		0				// BaseRelocationTable
-#ifdef CONFIG_DEBUG_EFI
+#if defined(PE_DLL_CHAR_EX) || defined(CONFIG_DEBUG_EFI)
 	.long		.Lefi_debug_table - .Ldoshdr	// DebugTable
 	.long		.Lefi_debug_table_size
+
+	.section	".rodata", "a"
+	.p2align	2
+.Lefi_debug_table:
+	// EFI_IMAGE_DEBUG_DIRECTORY_ENTRY[]
+#ifdef PE_DLL_CHAR_EX
+	.long		0					// Characteristics
+	.long		0					// TimeDateStamp
+	.short		0					// MajorVersion
+	.short		0					// MinorVersion
+	.long		IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS	// Type
+	.long		4					// SizeOfData
+	.long		0					// RVA
+	.long		.Lefi_dll_characteristics_ex - .Ldoshdr	// FileOffset
+#endif
+#ifdef CONFIG_DEBUG_EFI
+	.long		0					// Characteristics
+	.long		0					// TimeDateStamp
+	.short		0					// MajorVersion
+	.short		0					// MinorVersion
+	.long		IMAGE_DEBUG_TYPE_CODEVIEW		// Type
+	.long		.Lefi_debug_entry_size			// SizeOfData
+	.long		0					// RVA
+	.long		.Lefi_debug_entry - .Ldoshdr		// FileOffset
+#endif
+	.set		.Lefi_debug_table_size, . - .Lefi_debug_table
+	.previous
 #endif
 
 .Lsection_table:
@@ -110,23 +137,11 @@ __efistub_efi_zboot_header:
 
 	.set		.Lsection_count, (. - .Lsection_table) / 40
 
+#ifdef PE_DLL_CHAR_EX
+.Lefi_dll_characteristics_ex:
+	.long		PE_DLL_CHAR_EX
+#endif
 #ifdef CONFIG_DEBUG_EFI
-	.section	".rodata", "a"
-	.align		2
-.Lefi_debug_table:
-	// EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
-	.long		0				// Characteristics
-	.long		0				// TimeDateStamp
-	.short		0				// MajorVersion
-	.short		0				// MinorVersion
-	.long		IMAGE_DEBUG_TYPE_CODEVIEW	// Type
-	.long		.Lefi_debug_entry_size		// SizeOfData
-	.long		0				// RVA
-	.long		.Lefi_debug_entry - .Ldoshdr	// FileOffset
-
-	.set		.Lefi_debug_table_size, . - .Lefi_debug_table
-	.previous
-
 .Lefi_debug_entry:
 	// EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
 	.ascii		"NB10"				// Signature

drivers/firmware/efi/libstub/zboot.c

@@ -50,8 +50,7 @@ static unsigned long alloc_preferred_address(unsigned long alloc_size)
 }
 
 void __weak efi_cache_sync_image(unsigned long image_base,
-				 unsigned long alloc_size,
+				 unsigned long alloc_size)
-				 unsigned long code_size)
 {
 	// Provided by the arch to perform the cache maintenance necessary for
 	// executable code loaded into memory to be safe for execution.
@@ -66,7 +65,7 @@ asmlinkage efi_status_t __efiapi
 efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 {
 	unsigned long compressed_size = _gzdata_end - _gzdata_start;
-	unsigned long image_base, alloc_size, code_size;
+	unsigned long image_base, alloc_size;
 	efi_loaded_image_t *image;
 	efi_status_t status;
 	char *cmdline_ptr;
@@ -94,10 +93,6 @@ efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 	alloc_size = round_up(get_unaligned_le32(_gzdata_end - 4),
 			      EFI_ALLOC_ALIGN);
 
-	// SizeOfHeaders and SizeOfCode from the compressee's PE/COFF header
-	code_size = get_unaligned_le32(_gzdata_end - 8) +
-		    get_unaligned_le32(_gzdata_end - 12);
-
 	 // If the architecture has a preferred address for the image,
 	 // try that first.
 	image_base = alloc_preferred_address(alloc_size);
@@ -140,9 +135,7 @@ efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 		goto free_image;
 	}
 
-	efi_cache_sync_image(image_base, alloc_size, code_size);
+	efi_cache_sync_image(image_base, alloc_size);
-
-	efi_remap_image(image_base, alloc_size, code_size);
 
 	status = efi_stub_common(handle, image, image_base, cmdline_ptr);
 

drivers/firmware/efi/libstub/zboot.lds

@@ -2,6 +2,8 @@
 
 ENTRY(__efistub_efi_zboot_header);
 
+PROVIDE(zboot_code_size = ABSOLUTE(0));
+
 SECTIONS
 {
 	.head : ALIGN(4096) {
@@ -17,6 +19,11 @@ SECTIONS
 		*(.gzdata)
 		__efistub__gzdata_end = .;
 		*(.rodata* .init.rodata* .srodata*)
+
+		. = ALIGN(4);
+		__efistub_code_size = .;
+		LONG(zboot_code_size);
+
 		_etext = ALIGN(4096);
 		. = _etext;
 	}

include/linux/pe.h

@@ -118,6 +118,9 @@
 #define IMAGE_DLLCHARACTERISTICS_WDM_DRIVER             0x2000
 #define IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE  0x8000
 
+#define IMAGE_DLLCHARACTERISTICS_EX_CET_COMPAT		0x0001
+#define IMAGE_DLLCHARACTERISTICS_EX_FORWARD_CFI_COMPAT	0x0040
+
 /* they actually defined 0x00000000 as well, but I think we'll skip that one. */
 #define IMAGE_SCN_RESERVED_0	0x00000001
 #define IMAGE_SCN_RESERVED_1	0x00000002
@@ -165,6 +168,7 @@
 #define IMAGE_SCN_MEM_WRITE	0x80000000 /* writeable */
 
 #define IMAGE_DEBUG_TYPE_CODEVIEW	2
+#define IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS	20
 
 #ifndef __ASSEMBLY__