Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull EFI updates from Ingo Molnar:
 "The EFI changes in this cycle are much larger than usual, for two
  (positive) reasons:

   - The GRUB project is showing signs of life again, resulting in the
     introduction of the generic Linux/UEFI boot protocol, instead of
     x86 specific hacks which are increasingly difficult to maintain.
     There's hope that all future extensions will now go through that
     boot protocol.

   - Preparatory work for RISC-V EFI support.

  The main changes are:

   - Boot time GDT handling changes

   - Simplify handling of EFI properties table on arm64

   - Generic EFI stub cleanups, to improve command line handling, file
     I/O, memory allocation, etc.

   - Introduce a generic initrd loading method based on calling back
     into the firmware, instead of relying on the x86 EFI handover
     protocol or device tree.

   - Introduce a mixed mode boot method that does not rely on the x86
     EFI handover protocol either, and could potentially be adopted by
     other architectures (if another one ever surfaces where one
     execution mode is a superset of another)

   - Clean up the contents of 'struct efi', and move out everything that
     doesn't need to be stored there.

   - Incorporate support for UEFI spec v2.8A changes that permit
     firmware implementations to return EFI_UNSUPPORTED from UEFI
     runtime services at OS runtime, and expose a mask of which ones are
     supported or unsupported via a configuration table.

   - Partial fix for the lack of by-VA cache maintenance in the
     decompressor on 32-bit ARM.

   - Changes to load device firmware from EFI boot service memory
     regions

   - Various documentation updates and minor code cleanups and fixes"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  efi/libstub/arm: Fix spurious message that an initrd was loaded
  efi/libstub/arm64: Avoid image_base value from efi_loaded_image
  partitions/efi: Fix partition name parsing in GUID partition entry
  efi/x86: Fix cast of image argument
  efi/libstub/x86: Use ULONG_MAX as upper bound for all allocations
  efi: Fix a mistype in comments mentioning efivar_entry_iter_begin()
  efi/libstub: Avoid linking libstub/lib-ksyms.o into vmlinux
  efi/x86: Preserve %ebx correctly in efi_set_virtual_address_map()
  efi/x86: Ignore the memory attributes table on i386
  efi/x86: Don't relocate the kernel unless necessary
  efi/x86: Remove extra headroom for setup block
  efi/x86: Add kernel preferred address to PE header
  efi/x86: Decompress at start of PE image load address
  x86/boot/compressed/32: Save the output address instead of recalculating it
  efi/libstub/x86: Deal with exit() boot service returning
  x86/boot: Use unsigned comparison for addresses
  efi/x86: Avoid using code32_start
  efi/x86: Make efi32_pe_entry() more readable
  efi/x86: Respect 32-bit ABI in efi32_pe_entry()
  efi/x86: Annotate the LOADED_IMAGE_PROTOCOL_GUID with SYM_DATA
  ...

Author: torvalds

Documentation/driver-api/firmware/efi/index.rst

@@ -0,0 +1,11 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+UEFI Support
+============
+
+UEFI stub library functions
+===========================
+
+.. kernel-doc:: drivers/firmware/efi/libstub/mem.c
+   :internal:

Documentation/driver-api/firmware/index.rst

@@ -6,6 +6,7 @@ Linux Firmware API
 
    introduction
    core
+   efi/index
    request_firmware
    other_interfaces
 

Documentation/x86/boot.rst

@@ -490,15 +490,11 @@ Protocol:	2.00+
 		kernel) to not write early messages that require
 		accessing the display hardware directly.
 
-  Bit 6 (write): KEEP_SEGMENTS
+  Bit 6 (obsolete): KEEP_SEGMENTS
 
 	Protocol: 2.07+
 
-	- If 0, reload the segment registers in the 32bit entry point.
-	- If 1, do not reload the segment registers in the 32bit entry point.
-
-		Assume that %cs %ds %ss %es are all set to flat segments with
-		a base of 0 (or the equivalent for their environment).
+        - This flag is obsolete.
 
   Bit 7 (write): CAN_USE_HEAP
 

MAINTAINERS

@@ -6363,7 +6363,6 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git
 S:	Maintained
 F:	Documentation/admin-guide/efi-stub.rst
 F:	arch/*/kernel/efi.c
-F:	arch/x86/boot/compressed/eboot.[ch]
 F:	arch/*/include/asm/efi.h
 F:	arch/x86/platform/efi/
 F:	drivers/firmware/efi/

arch/arm/boot/compressed/efi-header.S

@@ -60,7 +60,7 @@ optional_header:
 		.long	__pecoff_code_size		@ SizeOfCode
 		.long	__pecoff_data_size		@ SizeOfInitializedData
 		.long	0				@ SizeOfUninitializedData
-		.long	efi_stub_entry - start		@ AddressOfEntryPoint
+		.long	efi_entry - start		@ AddressOfEntryPoint
 		.long	start_offset			@ BaseOfCode
 		.long	__pecoff_data_start - start	@ BaseOfData
 
@@ -70,8 +70,8 @@ extra_header_fields:
 		.long	SZ_512				@ FileAlignment
 		.short	0				@ MajorOsVersion
 		.short	0				@ MinorOsVersion
-		.short	0				@ MajorImageVersion
-		.short	0				@ MinorImageVersion
+		.short	LINUX_EFISTUB_MAJOR_VERSION	@ MajorImageVersion
+		.short	LINUX_EFISTUB_MINOR_VERSION	@ MinorImageVersion
 		.short	0				@ MajorSubsystemVersion
 		.short	0				@ MinorSubsystemVersion
 		.long	0				@ Win32VersionValue

arch/arm/boot/compressed/head.S

@@ -1437,29 +1437,25 @@ __enter_kernel:
 reloc_code_end:
 
 #ifdef CONFIG_EFI_STUB
-		.align	2
-_start:		.long	start - .
-
-ENTRY(efi_stub_entry)
-		@ allocate space on stack for passing current zImage address
-		@ and for the EFI stub to return of new entry point of
-		@ zImage, as EFI stub may copy the kernel. Pointer address
-		@ is passed in r2. r0 and r1 are passed through from the
-		@ EFI firmware to efi_entry
-		adr	ip, _start
-		ldr	r3, [ip]
-		add	r3, r3, ip
-		stmfd	sp!, {r3, lr}
-		mov	r2, sp			@ pass zImage address in r2
-		bl	efi_entry
-
-		@ Check for error return from EFI stub. r0 has FDT address
-		@ or error code.
-		cmn	r0, #1
-		beq	efi_load_fail
-
-		@ Preserve return value of efi_entry() in r4
-		mov	r4, r0
+ENTRY(efi_enter_kernel)
+		mov	r7, r0				@ preserve image base
+		mov	r4, r1				@ preserve DT pointer
+
+		mov	r0, r4				@ DT start
+		add	r1, r4, r2			@ DT end
+		bl	cache_clean_flush
+
+		mov	r0, r7				@ relocated zImage
+		ldr	r1, =_edata			@ size of zImage
+		add	r1, r1, r0			@ end of zImage
+		bl	cache_clean_flush
+
+		@ The PE/COFF loader might not have cleaned the code we are
+		@ running beyond the PoU, and so calling cache_off below from
+		@ inside the PE/COFF loader allocated region is unsafe unless
+		@ we explicitly clean it to the PoC.
+		adr	r0, call_cache_fn		@ region of code we will
+		adr	r1, 0f				@ run with MMU off
 		bl	cache_clean_flush
 		bl	cache_off
 
@@ -1469,18 +1465,10 @@ ENTRY(efi_stub_entry)
 		mov	r0, #0
 		mov	r1, #0xFFFFFFFF
 		mov	r2, r4
-
-		@ Branch to (possibly) relocated zImage that is in [sp]
-		ldr	lr, [sp]
-		ldr	ip, =start_offset
-		add	lr, lr, ip
-		mov	pc, lr				@ no mode switch
-
-efi_load_fail:
-		@ Return EFI_LOAD_ERROR to EFI firmware on error.
-		ldr	r0, =0x80000001
-		ldmfd	sp!, {ip, pc}
-ENDPROC(efi_stub_entry)
+		add	r7, r7, #(__efi_start - start)
+		mov	pc, r7				@ no mode switch
+ENDPROC(efi_enter_kernel)
+0:
 #endif
 
 		.align

arch/arm64/include/asm/efi.h

@@ -57,13 +57,6 @@ efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
 
 /* arch specific definitions used by the stub code */
 
-/*
- * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
- * start of kernel and may not cross a 2MiB boundary. We set alignment to
- * 2MiB so we know it won't cross a 2MiB boundary.
- */
-#define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
-
 /*
  * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
  * kernel need greater alignment than we require the segments to be padded to.
@@ -107,9 +100,6 @@ static inline void free_screen_info(struct screen_info *si)
 {
 }
 
-/* redeclare as 'hidden' so the compiler will generate relative references */
-extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
-
 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
 {
 }

arch/arm64/kernel/efi-entry.S

@@ -10,81 +10,35 @@
 
 #include <asm/assembler.h>
 
-#define EFI_LOAD_ERROR 0x8000000000000001
-
 	__INIT
 
-	/*
-	 * We arrive here from the EFI boot manager with:
-	 *
-	 *    * CPU in little-endian mode
-	 *    * MMU on with identity-mapped RAM
-	 *    * Icache and Dcache on
-	 *
-	 * We will most likely be running from some place other than where
-	 * we want to be. The kernel image wants to be placed at TEXT_OFFSET
-	 * from start of RAM.
-	 */
-ENTRY(entry)
-	/*
-	 * Create a stack frame to save FP/LR with extra space
-	 * for image_addr variable passed to efi_entry().
-	 */
-	stp	x29, x30, [sp, #-32]!
-	mov	x29, sp
-
-	/*
-	 * Call efi_entry to do the real work.
-	 * x0 and x1 are already set up by firmware. Current runtime
-	 * address of image is calculated and passed via *image_addr.
-	 *
-	 * unsigned long efi_entry(void *handle,
-	 *                         efi_system_table_t *sys_table,
-	 *                         unsigned long *image_addr) ;
-	 */
-	adr_l	x8, _text
-	add	x2, sp, 16
-	str	x8, [x2]
-	bl	efi_entry
-	cmn	x0, #1
-	b.eq	efi_load_fail
-
+SYM_CODE_START(efi_enter_kernel)
 	/*
 	 * efi_entry() will have copied the kernel image if necessary and we
-	 * return here with device tree address in x0 and the kernel entry
-	 * point stored at *image_addr. Save those values in registers which
-	 * are callee preserved.
-	 */
-	mov	x20, x0		// DTB address
-	ldr	x0, [sp, #16]	// relocated _text address
-	ldr	w21, =stext_offset
-	add	x21, x0, x21
-
-	/*
-	 * Calculate size of the kernel Image (same for original and copy).
+	 * end up here with device tree address in x1 and the kernel entry
+	 * point stored in x0. Save those values in registers which are
+	 * callee preserved.
 	 */
-	adr_l	x1, _text
-	adr_l	x2, _edata
-	sub	x1, x2, x1
+	ldr	w2, =stext_offset
+	add	x19, x0, x2		// relocated Image entrypoint
+	mov	x20, x1			// DTB address
 
 	/*
-	 * Flush the copied Image to the PoC, and ensure it is not shadowed by
+	 * Clean the copied Image to the PoC, and ensure it is not shadowed by
 	 * stale icache entries from before relocation.
 	 */
-	bl	__flush_dcache_area
+	ldr	w1, =kernel_size
+	bl	__clean_dcache_area_poc
 	ic	ialluis
 
 	/*
-	 * Ensure that the rest of this function (in the original Image) is
-	 * visible when the caches are disabled. The I-cache can't have stale
-	 * entries for the VA range of the current image, so no maintenance is
-	 * necessary.
+	 * Clean the remainder of this routine to the PoC
+	 * so that we can safely disable the MMU and caches.
 	 */
-	adr	x0, entry
-	adr	x1, entry_end
-	sub	x1, x1, x0
-	bl	__flush_dcache_area
-
+	adr	x0, 0f
+	ldr	w1, 3f
+	bl	__clean_dcache_area_poc
+0:
 	/* Turn off Dcache and MMU */
 	mrs	x0, CurrentEL
 	cmp	x0, #CurrentEL_EL2
@@ -109,12 +63,6 @@ ENTRY(entry)
 	mov	x1, xzr
 	mov	x2, xzr
 	mov	x3, xzr
-	br	x21
-
-efi_load_fail:
-	mov	x0, #EFI_LOAD_ERROR
-	ldp	x29, x30, [sp], #32
-	ret
-
-entry_end:
-ENDPROC(entry)
+	br	x19
+SYM_CODE_END(efi_enter_kernel)
+3:	.long	. - 0b

arch/arm64/kernel/efi-header.S

@@ -27,7 +27,7 @@ optional_header:
 	.long	__initdata_begin - efi_header_end	// SizeOfCode
 	.long	__pecoff_data_size			// SizeOfInitializedData
 	.long	0					// SizeOfUninitializedData
-	.long	__efistub_entry - _head			// AddressOfEntryPoint
+	.long	__efistub_efi_entry - _head		// AddressOfEntryPoint
 	.long	efi_header_end - _head			// BaseOfCode
 
 extra_header_fields:
@@ -36,8 +36,8 @@ extra_header_fields:
 	.long	PECOFF_FILE_ALIGNMENT			// FileAlignment
 	.short	0					// MajorOperatingSystemVersion
 	.short	0					// MinorOperatingSystemVersion
-	.short	0					// MajorImageVersion
-	.short	0					// MinorImageVersion
+	.short	LINUX_EFISTUB_MAJOR_VERSION		// MajorImageVersion
+	.short	LINUX_EFISTUB_MINOR_VERSION		// MinorImageVersion
 	.short	0					// MajorSubsystemVersion
 	.short	0					// MinorSubsystemVersion
 	.long	0					// Win32VersionValue

arch/arm64/kernel/image-vars.h

@@ -12,7 +12,9 @@
 
 #ifdef CONFIG_EFI
 
-__efistub_stext_offset = stext - _text;
+__efistub_kernel_size		= _edata - _text;
+__efistub_stext_offset		= stext - _text;
+
 
 /*
  * The EFI stub has its own symbol namespace prefixed by __efistub_, to
@@ -33,7 +35,7 @@ __efistub_strnlen		= __pi_strnlen;
 __efistub_strcmp		= __pi_strcmp;
 __efistub_strncmp		= __pi_strncmp;
 __efistub_strrchr		= __pi_strrchr;
-__efistub___flush_dcache_area	= __pi___flush_dcache_area;
+__efistub___clean_dcache_area_poc = __pi___clean_dcache_area_poc;
 
 #ifdef CONFIG_KASAN
 __efistub___memcpy		= __pi_memcpy;
@@ -45,6 +47,7 @@ __efistub__text			= _text;
 __efistub__end			= _end;
 __efistub__edata		= _edata;
 __efistub_screen_info		= screen_info;
+__efistub__ctype		= _ctype;
 
 #endif