diff options
Diffstat (limited to 'arch/x86/boot/header.S')
| -rw-r--r-- | arch/x86/boot/header.S | 434 |
1 files changed, 274 insertions, 160 deletions
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 9ec06a1f6d61..9bea5a1e2c52 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * header.S * @@ -14,11 +15,9 @@ * hex while segment addresses are written as segment:offset. * */ - +#include <linux/pe.h> #include <asm/segment.h> -#include <generated/utsrelease.h> #include <asm/boot.h> -#include <asm/e820.h> #include <asm/page_types.h> #include <asm/setup.h> #include <asm/bootparam.h> @@ -37,114 +36,56 @@ SYSSEG = 0x1000 /* historical load address >> 4 */ #define ROOT_RDONLY 1 #endif + .set salign, 0x1000 + .set falign, 0x200 + .code16 .section ".bstext", "ax" - - .global bootsect_start -bootsect_start: #ifdef CONFIG_EFI_STUB # "MZ", MS-DOS header - .byte 0x4d - .byte 0x5a -#endif - - # Normalize the start address - ljmp $BOOTSEG, $start2 - -start2: - movw %cs, %ax - movw %ax, %ds - movw %ax, %es - movw %ax, %ss - xorw %sp, %sp - sti - cld - - movw $bugger_off_msg, %si - -msg_loop: - lodsb - andb %al, %al - jz bs_die - movb $0xe, %ah - movw $7, %bx - int $0x10 - jmp msg_loop - -bs_die: - # Allow the user to press a key, then reboot - xorw %ax, %ax - int $0x16 - int $0x19 - - # int 0x19 should never return. In case it does anyway, - # invoke the BIOS reset code... - ljmp $0xf000,$0xfff0 - -#ifdef CONFIG_EFI_STUB - .org 0x3c + .word IMAGE_DOS_SIGNATURE + .org 0x38 # # Offset to the PE header. # + .long LINUX_PE_MAGIC .long pe_header -#endif /* CONFIG_EFI_STUB */ - - .section ".bsdata", "a" -bugger_off_msg: - .ascii "Direct floppy boot is not supported. " - .ascii "Use a boot loader program instead.\r\n" - .ascii "\n" - .ascii "Remove disk and press any key to reboot ...\r\n" - .byte 0 - -#ifdef CONFIG_EFI_STUB pe_header: - .ascii "PE" - .word 0 + .long IMAGE_NT_SIGNATURE coff_header: #ifdef CONFIG_X86_32 - .word 0x14c # i386 + .set image_file_add_flags, IMAGE_FILE_32BIT_MACHINE + .set pe_opt_magic, IMAGE_NT_OPTIONAL_HDR32_MAGIC + .word IMAGE_FILE_MACHINE_I386 #else - .word 0x8664 # x86-64 + .set image_file_add_flags, 0 + .set pe_opt_magic, IMAGE_NT_OPTIONAL_HDR64_MAGIC + .word IMAGE_FILE_MACHINE_AMD64 #endif - .word 3 # nr_sections + .word section_count # nr_sections .long 0 # TimeDateStamp .long 0 # PointerToSymbolTable .long 1 # NumberOfSymbols .word section_table - optional_header # SizeOfOptionalHeader -#ifdef CONFIG_X86_32 - .word 0x306 # Characteristics. - # IMAGE_FILE_32BIT_MACHINE | - # IMAGE_FILE_DEBUG_STRIPPED | - # IMAGE_FILE_EXECUTABLE_IMAGE | - # IMAGE_FILE_LINE_NUMS_STRIPPED -#else - .word 0x206 # Characteristics - # IMAGE_FILE_DEBUG_STRIPPED | - # IMAGE_FILE_EXECUTABLE_IMAGE | - # IMAGE_FILE_LINE_NUMS_STRIPPED -#endif + .word IMAGE_FILE_EXECUTABLE_IMAGE | \ + image_file_add_flags | \ + IMAGE_FILE_DEBUG_STRIPPED | \ + IMAGE_FILE_LINE_NUMS_STRIPPED # Characteristics optional_header: -#ifdef CONFIG_X86_32 - .word 0x10b # PE32 format -#else - .word 0x20b # PE32+ format -#endif + .word pe_opt_magic .byte 0x02 # MajorLinkerVersion .byte 0x14 # MinorLinkerVersion - # Filled in by build.c - .long 0 # SizeOfCode + .long ZO__data # SizeOfCode - .long 0 # SizeOfInitializedData + .long ZO__end - ZO__data # SizeOfInitializedData .long 0 # SizeOfUninitializedData - # Filled in by build.c - .long 0x0000 # AddressOfEntryPoint + .long setup_size + ZO_efi_pe_entry # AddressOfEntryPoint - .long 0x0200 # BaseOfCode + .long setup_size # BaseOfCode #ifdef CONFIG_X86_32 .long 0 # data #endif @@ -155,25 +96,22 @@ extra_header_fields: #else .quad 0 # ImageBase #endif - .long 0x20 # SectionAlignment - .long 0x20 # FileAlignment + .long salign # SectionAlignment + .long falign # FileAlignment .word 0 # MajorOperatingSystemVersion .word 0 # MinorOperatingSystemVersion - .word 0 # MajorImageVersion - .word 0 # MinorImageVersion + .word LINUX_EFISTUB_MAJOR_VERSION # MajorImageVersion + .word LINUX_EFISTUB_MINOR_VERSION # MinorImageVersion .word 0 # MajorSubsystemVersion .word 0 # MinorSubsystemVersion .long 0 # Win32VersionValue - # - # The size of the bzImage is written in tools/build.c - # - .long 0 # SizeOfImage + .long setup_size + ZO__end # SizeOfImage - .long 0x200 # SizeOfHeaders + .long salign # SizeOfHeaders .long 0 # CheckSum - .word 0xa # Subsystem (EFI application) - .word 0 # DllCharacteristics + .word IMAGE_SUBSYSTEM_EFI_APPLICATION # Subsystem (EFI application) + .word IMAGE_DLLCHARACTERISTICS_NX_COMPAT # DllCharacteristics #ifdef CONFIG_X86_32 .long 0 # SizeOfStackReserve .long 0 # SizeOfStackCommit @@ -186,7 +124,7 @@ extra_header_fields: .quad 0 # SizeOfHeapCommit #endif .long 0 # LoaderFlags - .long 0x6 # NumberOfRvaAndSizes + .long (section_table - .) / 8 # NumberOfRvaAndSizes .quad 0 # ExportTable .quad 0 # ImportTable @@ -197,59 +135,92 @@ extra_header_fields: # Section table section_table: - # - # The offset & size fields are filled in by build.c. - # .ascii ".setup" .byte 0 .byte 0 - .long 0 - .long 0x0 # startup_{32,64} - .long 0 # Size of initialized data - # on disk - .long 0x0 # startup_{32,64} + .long pecompat_fstart - salign # VirtualSize + .long salign # VirtualAddress + .long pecompat_fstart - salign # SizeOfRawData + .long salign # PointerToRawData + + .long 0, 0, 0 + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_DISCARDABLE # Characteristics + +#ifdef CONFIG_EFI_MIXED + .asciz ".compat" + + .long pecompat_fsize # VirtualSize + .long pecompat_fstart # VirtualAddress + .long pecompat_fsize # SizeOfRawData + .long pecompat_fstart # PointerToRawData + + .long 0, 0, 0 + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_DISCARDABLE # Characteristics + + /* + * Put the IA-32 machine type and the associated entry point address in + * the .compat section, so loaders can figure out which other execution + * modes this image supports. + */ + .pushsection ".pecompat", "a", @progbits + .balign salign + .globl pecompat_fstart +pecompat_fstart: + .byte 0x1 # Version + .byte 8 # Size + .word IMAGE_FILE_MACHINE_I386 # PE machine type + .long setup_size + ZO_efi32_pe_entry # Entrypoint + .byte 0x0 # Sentinel + .popsection +#else + .set pecompat_fstart, setup_size +#endif + .ascii ".text\0\0\0" + .long textsize # VirtualSize + .long setup_size # VirtualAddress + .long textsize # SizeOfRawData + .long setup_size # PointerToRawData .long 0 # PointerToRelocations .long 0 # PointerToLineNumbers .word 0 # NumberOfRelocations .word 0 # NumberOfLineNumbers - .long 0x60500020 # Characteristics (section flags) + .long IMAGE_SCN_CNT_CODE | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_EXECUTE # Characteristics + +#ifdef CONFIG_EFI_SBAT + .ascii ".sbat\0\0\0" + .long ZO__esbat - ZO__sbat # VirtualSize + .long setup_size + ZO__sbat # VirtualAddress + .long ZO__esbat - ZO__sbat # SizeOfRawData + .long setup_size + ZO__sbat # PointerToRawData + + .long 0, 0, 0 + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_DISCARDABLE # Characteristics + + .set textsize, ZO__sbat +#else + .set textsize, ZO__data +#endif - # - # The EFI application loader requires a relocation section - # because EFI applications must be relocatable. The .reloc - # offset & size fields are filled in by build.c. - # - .ascii ".reloc" - .byte 0 - .byte 0 - .long 0 - .long 0 - .long 0 # SizeOfRawData - .long 0 # PointerToRawData - .long 0 # PointerToRelocations - .long 0 # PointerToLineNumbers - .word 0 # NumberOfRelocations - .word 0 # NumberOfLineNumbers - .long 0x42100040 # Characteristics (section flags) + .ascii ".data\0\0\0" + .long ZO__end - ZO__data # VirtualSize + .long setup_size + ZO__data # VirtualAddress + .long ZO__edata - ZO__data # SizeOfRawData + .long setup_size + ZO__data # PointerToRawData - # - # The offset & size fields are filled in by build.c. - # - .ascii ".text" - .byte 0 - .byte 0 - .byte 0 - .long 0 - .long 0x0 # startup_{32,64} - .long 0 # Size of initialized data - # on disk - .long 0x0 # startup_{32,64} - .long 0 # PointerToRelocations - .long 0 # PointerToLineNumbers - .word 0 # NumberOfRelocations - .word 0 # NumberOfLineNumbers - .long 0x60500020 # Characteristics (section flags) + .long 0, 0, 0 + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_WRITE # Characteristics + .set section_count, (. - section_table) / 40 #endif /* CONFIG_EFI_STUB */ # Kernel attributes; used by setup. This is part 1 of the @@ -261,12 +232,12 @@ sentinel: .byte 0xff, 0xff /* Used to detect broken loaders */ .globl hdr hdr: -setup_sects: .byte 0 /* Filled in by build.c */ + .byte setup_sects - 1 root_flags: .word ROOT_RDONLY -syssize: .long 0 /* Filled in by build.c */ +syssize: .long ZO__edata / 16 ram_size: .word 0 /* Obsolete */ vid_mode: .word SVGA_MODE -root_dev: .word 0 /* Filled in by build.c */ +root_dev: .word 0 /* Default to major/minor 0/0 */ boot_flag: .word 0xAA55 # offset 512, entry point @@ -283,7 +254,7 @@ _start: # Part 2 of the header, from the old setup.S .ascii "HdrS" # header signature - .word 0x020c # header version number (>= 0x0105) + .word 0x020f # header version number (>= 0x0105) # or else old loadlin-1.5 will fail) .globl realmode_swtch realmode_swtch: .word 0, 0 # default_switch, SETUPSEG @@ -296,7 +267,7 @@ start_sys_seg: .word SYSSEG # obsolete and meaningless, but just type_of_loader: .byte 0 # 0 means ancient bootloader, newer # bootloaders know to change this. - # See Documentation/x86/boot.txt for + # See Documentation/arch/x86/boot.rst for # assigned ids # flags, unused bits must be zero (RFU) bit within loadflags @@ -350,7 +321,7 @@ cmd_line_ptr: .long 0 # (Header version 0x0202 or later) # can be located anywhere in # low memory 0x10000 or higher. -ramdisk_max: .long 0x7fffffff +initrd_addr_max: .long 0x7fffffff # (Header version 0x0203 or later) # The highest safe address for # the contents of an initrd @@ -382,16 +353,33 @@ xloadflags: # define XLF1 0 #endif -#ifdef CONFIG_EFI_STUB -# ifdef CONFIG_X86_64 -# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */ +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL +# ifdef CONFIG_EFI_MIXED +# define XLF23 (XLF_EFI_HANDOVER_32|XLF_EFI_HANDOVER_64) # else -# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */ +# ifdef CONFIG_X86_64 +# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */ +# else +# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */ +# endif # endif #else # define XLF23 0 #endif - .word XLF0 | XLF1 | XLF23 + +#if defined(CONFIG_X86_64) && defined(CONFIG_EFI) && defined(CONFIG_KEXEC_CORE) +# define XLF4 XLF_EFI_KEXEC +#else +# define XLF4 0 +#endif + +#ifdef CONFIG_X86_64 +#define XLF56 (XLF_5LEVEL|XLF_5LEVEL_ENABLED) +#else +#define XLF56 0 +#endif + + .word XLF0 | XLF1 | XLF23 | XLF4 | XLF56 cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line, #added with boot protocol @@ -411,21 +399,147 @@ setup_data: .quad 0 # 64-bit physical pointer to pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr -#define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset) +# +# Getting to provably safe in-place decompression is hard. Worst case +# behaviours need to be analyzed. Here let's take the decompression of +# a gzip-compressed kernel as example, to illustrate it: +# +# The file layout of gzip compressed kernel is: +# +# magic[2] +# method[1] +# flags[1] +# timestamp[4] +# extraflags[1] +# os[1] +# compressed data blocks[N] +# crc[4] orig_len[4] +# +# ... resulting in +18 bytes overhead of uncompressed data. +# +# (For more information, please refer to RFC 1951 and RFC 1952.) +# +# Files divided into blocks +# 1 bit (last block flag) +# 2 bits (block type) +# +# 1 block occurs every 32K -1 bytes or when there 50% compression +# has been achieved. The smallest block type encoding is always used. +# +# stored: +# 32 bits length in bytes. +# +# fixed: +# magic fixed tree. +# symbols. +# +# dynamic: +# dynamic tree encoding. +# symbols. +# +# +# The buffer for decompression in place is the length of the uncompressed +# data, plus a small amount extra to keep the algorithm safe. The +# compressed data is placed at the end of the buffer. The output pointer +# is placed at the start of the buffer and the input pointer is placed +# where the compressed data starts. Problems will occur when the output +# pointer overruns the input pointer. +# +# The output pointer can only overrun the input pointer if the input +# pointer is moving faster than the output pointer. A condition only +# triggered by data whose compressed form is larger than the uncompressed +# form. +# +# The worst case at the block level is a growth of the compressed data +# of 5 bytes per 32767 bytes. +# +# The worst case internal to a compressed block is very hard to figure. +# The worst case can at least be bounded by having one bit that represents +# 32764 bytes and then all of the rest of the bytes representing the very +# very last byte. +# +# All of which is enough to compute an amount of extra data that is required +# to be safe. To avoid problems at the block level allocating 5 extra bytes +# per 32767 bytes of data is sufficient. To avoid problems internal to a +# block adding an extra 32767 bytes (the worst case uncompressed block size) +# is sufficient, to ensure that in the worst case the decompressed data for +# block will stop the byte before the compressed data for a block begins. +# To avoid problems with the compressed data's meta information an extra 18 +# bytes are needed. Leading to the formula: +# +# extra_bytes = (uncompressed_size >> 12) + 32768 + 18 +# +# Adding 8 bytes per 32K is a bit excessive but much easier to calculate. +# Adding 32768 instead of 32767 just makes for round numbers. +# +# Above analysis is for decompressing gzip compressed kernel only. Up to +# now 6 different decompressor are supported all together. And among them +# xz stores data in chunks and has maximum chunk of 64K. Hence safety +# margin should be updated to cover all decompressors so that we don't +# need to deal with each of them separately. Please check +# the description in lib/decompressor_xxx.c for specific information. +# +# extra_bytes = (uncompressed_size >> 12) + 65536 + 128 +# +# LZ4 is even worse: data that cannot be further compressed grows by 0.4%, +# or one byte per 256 bytes. OTOH, we can safely get rid of the +128 as +# the size-dependent part now grows so fast. +# +# extra_bytes = (uncompressed_size >> 8) + 65536 +# +# ZSTD compressed data grows by at most 3 bytes per 128K, and only has a 22 +# byte fixed overhead but has a maximum block size of 128K, so it needs a +# larger margin. +# +# extra_bytes = (uncompressed_size >> 8) + 131072 + +#define ZO_z_extra_bytes ((ZO_z_output_len >> 8) + 131072) +#if ZO_z_output_len > ZO_z_input_len +# define ZO_z_extract_offset (ZO_z_output_len + ZO_z_extra_bytes - \ + ZO_z_input_len) +#else +# define ZO_z_extract_offset ZO_z_extra_bytes +#endif + +/* + * The extract_offset has to be bigger than ZO head section. Otherwise when + * the head code is running to move ZO to the end of the buffer, it will + * overwrite the head code itself. + */ +#if (ZO__ehead - ZO_startup_32) > ZO_z_extract_offset +# define ZO_z_min_extract_offset ((ZO__ehead - ZO_startup_32 + 4095) & ~4095) +#else +# define ZO_z_min_extract_offset ((ZO_z_extract_offset + 4095) & ~4095) +#endif + +#define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_min_extract_offset) + #define VO_INIT_SIZE (VO__end - VO__text) #if ZO_INIT_SIZE > VO_INIT_SIZE -#define INIT_SIZE ZO_INIT_SIZE +# define INIT_SIZE ZO_INIT_SIZE #else -#define INIT_SIZE VO_INIT_SIZE +# define INIT_SIZE VO_INIT_SIZE #endif -init_size: .long INIT_SIZE # kernel initialization size -handover_offset: -#ifdef CONFIG_EFI_STUB - .long 0x30 # offset to the handover - # protocol entry point + + .macro __handover_offset +#ifndef CONFIG_EFI_HANDOVER_PROTOCOL + .long 0 +#elif !defined(CONFIG_X86_64) + .long ZO_efi32_stub_entry #else - .long 0 + /* Yes, this is really how we defined it :( */ + .long ZO_efi64_stub_entry - 0x200 +#ifdef CONFIG_EFI_MIXED + .if ZO_efi32_stub_entry != ZO_efi64_stub_entry - 0x200 + .error "32-bit and 64-bit EFI entry points do not match" + .endif +#endif #endif + .endm + +init_size: .long INIT_SIZE # kernel initialization size +handover_offset: __handover_offset +kernel_info_offset: .long ZO_kernel_info # End of setup header ##################################################### @@ -480,7 +594,7 @@ start_of_setup: xorl %eax, %eax subw %di, %cx shrw $2, %cx - rep; stosl + rep stosl # Jump to C code (should not return) calll main |