/* * Copyright (C) 2006 Michael Brown . * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ FILE_LICENCE ( GPL2_OR_LATER ) .arch i386 /* Image compression enabled */ #define COMPRESS 1 /* Protected mode flag */ #define CR0_PE 1 /* Allow for DBG()-style messages within libprefix */ #ifdef NDEBUG .macro progress message .endm #else .macro progress message pushfl pushw %ds pushw %si pushw %di pushw %cs popw %ds xorw %di, %di movw $progress_\@, %si call print_message popw %di popw %si popw %ds popfl .section ".prefix.data", "aw", @progbits progress_\@: .asciz "\message" .size progress_\@, . - progress_\@ .previous .endm #endif /***************************************************************************** * Utility function: print character (with LF -> LF,CR translation) * * Parameters: * %al : character to print * %ds:di : output buffer (or %di=0 to print to console) * Returns: * %ds:di : next character in output buffer (if applicable) ***************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl print_character print_character: /* Preserve registers */ pushw %ax pushw %bx pushw %bp /* If %di is non-zero, write character to buffer and exit */ testw %di, %di jz 1f movb %al, %ds:(%di) incw %di jmp 3f 1: /* Print character */ movw $0x0007, %bx /* page 0, attribute 7 (normal) */ movb $0x0e, %ah /* write char, tty mode */ cmpb $0x0a, %al /* '\n'? */ jne 2f int $0x10 movb $0x0d, %al 2: int $0x10 /* Restore registers and return */ 3: popw %bp popw %bx popw %ax ret .size print_character, . - print_character /***************************************************************************** * Utility function: print a NUL-terminated string * * Parameters: * %ds:si : string to print * %ds:di : output buffer (or %di=0 to print to console) * Returns: * %ds:si : character after terminating NUL * %ds:di : next character in output buffer (if applicable) ***************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl print_message print_message: /* Preserve registers */ pushw %ax /* Print string */ 1: lodsb testb %al, %al je 2f call print_character jmp 1b 2: /* Restore registers and return */ popw %ax ret .size print_message, . - print_message /***************************************************************************** * Utility functions: print hex digit/byte/word/dword * * Parameters: * %al (low nibble) : digit to print * %al : byte to print * %ax : word to print * %eax : dword to print * %ds:di : output buffer (or %di=0 to print to console) * Returns: * %ds:di : next character in output buffer (if applicable) ***************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl print_hex_dword print_hex_dword: rorl $16, %eax call print_hex_word rorl $16, %eax /* Fall through */ .size print_hex_dword, . - print_hex_dword .globl print_hex_word print_hex_word: xchgb %al, %ah call print_hex_byte xchgb %al, %ah /* Fall through */ .size print_hex_word, . - print_hex_word .globl print_hex_byte print_hex_byte: rorb $4, %al call print_hex_nibble rorb $4, %al /* Fall through */ .size print_hex_byte, . - print_hex_byte .globl print_hex_nibble print_hex_nibble: /* Preserve registers */ pushw %ax /* Print digit (technique by Norbert Juffa */ andb $0x0f, %al cmpb $10, %al sbbb $0x69, %al das call print_character /* Restore registers and return */ popw %ax ret .size print_hex_nibble, . - print_hex_nibble /***************************************************************************** * Utility function: print PCI bus:dev.fn * * Parameters: * %ax : PCI bus:dev.fn to print * %ds:di : output buffer (or %di=0 to print to console) * Returns: * %ds:di : next character in output buffer (if applicable) ***************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl print_pci_busdevfn print_pci_busdevfn: /* Preserve registers */ pushw %ax /* Print bus */ xchgb %al, %ah call print_hex_byte /* Print ":" */ movb $( ':' ), %al call print_character /* Print device */ movb %ah, %al shrb $3, %al call print_hex_byte /* Print "." */ movb $( '.' ), %al call print_character /* Print function */ movb %ah, %al andb $0x07, %al call print_hex_nibble /* Restore registers and return */ popw %ax ret .size print_pci_busdevfn, . - print_pci_busdevfn /***************************************************************************** * Utility function: clear current line * * Parameters: * %ds:di : output buffer (or %di=0 to print to console) * Returns: * %ds:di : next character in output buffer (if applicable) ***************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl print_kill_line print_kill_line: /* Preserve registers */ pushw %ax pushw %cx /* Print CR */ movb $( '\r' ), %al call print_character /* Print 79 spaces */ movb $( ' ' ), %al movw $79, %cx 1: call print_character loop 1b /* Print CR */ movb $( '\r' ), %al call print_character /* Restore registers and return */ popw %cx popw %ax ret .size print_kill_line, . - print_kill_line /**************************************************************************** * copy_bytes * * Copy bytes * * Parameters: * %ds:esi : source address * %es:edi : destination address * %ecx : length * Returns: * %ds:esi : next source address * %es:edi : next destination address * Corrupts: * None **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 copy_bytes: pushl %ecx rep addr32 movsb popl %ecx ret .size copy_bytes, . - copy_bytes /**************************************************************************** * zero_bytes * * Zero bytes * * Parameters: * %ds:esi : source address * %es:edi : destination address * %ecx : length * Returns: * %ds:esi : next source address * %es:edi : next destination address * Corrupts: * None **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 zero_bytes: pushl %ecx pushw %ax xorw %ax, %ax rep addr32 stosb popw %ax popl %ecx ret .size zero_bytes, . - zero_bytes /**************************************************************************** * process_bytes * * Call memcpy()-like function * * Parameters: * %esi : source physical address * %edi : destination physical address * %ecx : length * %bx : memcpy()-like function to call, passing parameters: * %ds:esi : source address * %es:edi : destination address * %ecx : length * and returning: * %ds:esi : next source address * %es:edi : next destination address * Returns: * %esi : next source physical address * %edi : next destination physical address * Corrupts: * None **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 process_bytes: #ifndef KEEP_IT_REAL /* Preserve registers */ pushl %eax pushl %ebp /* Construct GDT on stack (since .prefix may not be writable) */ .equ PM_DS, 0x18 /* Flat data segment */ pushl $0x00cf9300 pushl $0x0000ffff .equ PM_SS, 0x10 /* Stack segment based at %ss:0000 */ pushl $0x008f0930 pushw %ss pushw $0xffff .equ PM_CS, 0x08 /* Code segment based at %cs:0000 */ pushl $0x008f09b0 pushw %cs pushw $0xffff pushl $0 /* Base and length */ pushw %ss pushw $0x1f movzwl %sp, %ebp shll $4, 0x02(%bp) addl %ebp, 0x02(%bp) shll $4, 0x0a(%bp) shll $4, 0x12(%bp) subw $8, %sp sgdt -8(%bp) /* Switch to protected mode */ pushw %gs pushw %fs pushw %es pushw %ds pushw %ss pushw %cs pushw $2f cli data32 lgdt (%bp) movl %cr0, %eax orb $CR0_PE, %al movl %eax, %cr0 ljmp $PM_CS, $1f 1: movw $PM_SS, %ax movw %ax, %ss movw $PM_DS, %ax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs /* Call memcpy()-like function */ call *%bx /* Return to (flat) real mode */ movl %cr0, %eax andb $0!CR0_PE, %al movl %eax, %cr0 lret 2: /* lret will ljmp to here */ popw %ss popw %ds popw %es popw %fs popw %gs /* Restore GDT */ data32 lgdt -8(%bp) addw $( 8 /* saved GDT */ + ( PM_DS + 8 ) /* GDT on stack */ ), %sp /* Restore registers and return */ popl %ebp popl %eax ret #else /* KEEP_IT_REAL */ /* Preserve registers */ pushl %eax pushw %ds pushw %es /* Convert %esi and %edi to %ds:esi and %es:edi */ shrl $4, %esi movw %si, %ds xorw %si, %si shll $4, %esi shrl $4, %edi movw %di, %es xorw %di, %di shll $4, %edi /* Call memcpy()-like function */ call *%bx /* Convert %ds:esi and %es:edi back to physical addresses */ xorl %eax, %eax movw %ds, %cx shll $4, %eax addl %eax, %esi xorl %eax, %eax movw %es, %cx shll $4, %eax addl %eax, %edi /* Restore registers and return */ popw %es popw %ds popl %eax ret #endif /* KEEP_IT_REAL */ .size process_bytes, . - process_bytes /**************************************************************************** * install_block * * Install block to specified address * * Parameters: * %esi : source physical address (must be a multiple of 16) * %edi : destination physical address (must be a multiple of 16) * %ecx : length of (decompressed) data * %edx : total length of block (including any uninitialised data portion) * Returns: * %esi : next source physical address (will be a multiple of 16) * %edi : next destination physical address (will be a multiple of 16) * Corrupts: * none **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 install_block: /* Preserve registers */ pushl %ecx pushw %bx /* Decompress (or copy) source to destination */ #if COMPRESS movw $decompress16, %bx #else movw $copy_bytes, %bx #endif call process_bytes /* Zero .bss portion */ negl %ecx addl %edx, %ecx movw $zero_bytes, %bx call process_bytes /* Round up %esi and %edi to start of next blocks */ addl $0xf, %esi andl $~0xf, %esi addl $0xf, %edi andl $~0xf, %edi /* Restore registers and return */ popw %bx popl %ecx ret .size install_block, . - install_block /**************************************************************************** * alloc_basemem * * Allocate space for .text16 and .data16 from top of base memory. * Memory is allocated using the BIOS free base memory counter at * 0x40:13. * * Parameters: * none * Returns: * %ax : .text16 segment address * %bx : .data16 segment address * Corrupts: * none **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl alloc_basemem alloc_basemem: /* Preserve registers */ pushw %fs /* FBMS => %ax as segment address */ pushw $0x40 popw %fs movw %fs:0x13, %ax shlw $6, %ax /* Calculate .data16 segment address */ subw $_data16_memsz_pgh, %ax pushw %ax /* Calculate .text16 segment address */ subw $_text16_memsz_pgh, %ax pushw %ax /* Update FBMS */ shrw $6, %ax movw %ax, %fs:0x13 /* Retrieve .text16 and .data16 segment addresses */ popw %ax popw %bx /* Restore registers and return */ popw %fs ret .size alloc_basemem, . - alloc_basemem /**************************************************************************** * free_basemem * * Free space allocated with alloc_basemem. * * Parameters: * %ax : .text16 segment address * %bx : .data16 segment address * Returns: * %ax : 0 if successfully freed * Corrupts: * none **************************************************************************** */ .section ".text16", "ax", @progbits .code16 .globl free_basemem free_basemem: /* Preserve registers */ pushw %fs /* Check FBMS counter */ pushw %ax shrw $6, %ax pushw $0x40 popw %fs cmpw %ax, %fs:0x13 popw %ax jne 1f /* Check hooked interrupt count */ cmpw $0, %cs:hooked_bios_interrupts jne 1f /* OK to free memory */ addw $_text16_memsz_pgh, %ax addw $_data16_memsz_pgh, %ax shrw $6, %ax movw %ax, %fs:0x13 xorw %ax, %ax 1: /* Restore registers and return */ popw %fs ret .size free_basemem, . - free_basemem .section ".text16.data", "aw", @progbits .globl hooked_bios_interrupts hooked_bios_interrupts: .word 0 .size hooked_bios_interrupts, . - hooked_bios_interrupts /**************************************************************************** * install * * Install all text and data segments. * * Parameters: * none * Returns: * %ax : .text16 segment address * %bx : .data16 segment address * Corrupts: * none **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl install install: progress "install:\n" /* Preserve registers */ pushl %esi pushl %edi pushl %ebp /* Allocate space for .text16 and .data16 */ call alloc_basemem /* Image source = %cs:0000 */ xorl %esi, %esi /* Image destination = default */ xorl %edi, %edi /* Allow arbitrary relocation */ xorl %ebp, %ebp /* Install text and data segments */ call install_prealloc /* Restore registers and return */ popl %ebp popl %edi popl %esi ret .size install, . - install /**************************************************************************** * install_prealloc * * Install all text and data segments. * * Parameters: * %ax : .text16 segment address * %bx : .data16 segment address * %esi : Image source physical address (or zero for %cs:0000) * %edi : Decompression temporary area physical address (or zero for default) * %ebp : Maximum end address for relocation (or zero for no maximum) * Corrupts: * none **************************************************************************** */ .section ".prefix.lib", "awx", @progbits .code16 .globl install_prealloc install_prealloc: progress "install_prealloc:\n" /* Save registers */ pushal pushw %ds pushw %es cld /* Sanity: clear the direction flag asap */ /* Set up %ds for (read-only) access to .prefix */ pushw %cs popw %ds /* Save decompression temporary area physical address */ pushl %edi /* Install .text16.early */ progress " .text16.early\n" pushl %esi xorl %esi, %esi movw %cs, %si shll $4, %esi addl $_text16_early_lma, %esi movzwl %ax, %edi shll $4, %edi movl $_text16_early_filesz, %ecx movl $_text16_early_memsz, %edx call install_block /* .text16.early */ popl %esi #ifndef KEEP_IT_REAL /* Access high memory by enabling the A20 gate. (We will * already have 4GB segment limits as a result of calling * install_block.) */ progress " access_highmem\n" pushw %cs pushw $1f pushw %ax pushw $access_highmem lret 1: /* Die if we could not access high memory */ jnc 3f movw $a20_death_message, %si xorw %di, %di call print_message 2: jmp 2b .section ".prefix.data", "aw", @progbits a20_death_message: .asciz "\nHigh memory inaccessible - cannot continue\n" .size a20_death_message, . - a20_death_message .previous 3: #endif /* Open payload (which may not yet be in memory) */ progress " open_payload\n" pushw %cs pushw $1f pushw %ax pushw $open_payload lret 1: /* Die if we could not access the payload */ jnc 3f xorw %di, %di movl %esi, %eax call print_hex_dword movw $payload_death_message, %si call print_message 2: jmp 2b .section ".prefix.data", "aw", @progbits payload_death_message: .asciz "\nPayload inaccessible - cannot continue\n" .size payload_death_message, . - payload_death_message .previous 3: /* Calculate physical address of payload (i.e. first source) */ testl %esi, %esi jnz 1f movw %cs, %si shll $4, %esi 1: addl payload_lma, %esi /* Install .text16.late and .data16 */ progress " .text16.late\n" movl $_text16_late_filesz, %ecx movl $_text16_late_memsz, %edx call install_block /* .text16.late */ progress " .data16\n" movzwl %bx, %edi shll $4, %edi movl $_data16_filesz, %ecx movl $_data16_memsz, %edx call install_block /* .data16 */ /* Set up %ds for access to .data16 */ movw %bx, %ds /* Restore decompression temporary area physical address */ popl %edi #ifdef KEEP_IT_REAL /* Initialise libkir */ movw %ax, (init_libkir_vector+2) lcall *init_libkir_vector #else /* Find a suitable decompression temporary area, if none specified */ pushl %eax testl %edi, %edi jnz 1f /* Use INT 15,88 to find the highest available address via INT * 15,88. This limits us to around 64MB, which should avoid * all of the POST-time memory map failure modes. */ movb $0x88, %ah int $0x15 movw %ax, %di addl $0x400, %edi subl $_textdata_memsz_kb, %edi shll $10, %edi /* Sanity check: if we have ended up below 1MB, use 1MB */ cmpl $0x100000, %edi jae 1f movl $0x100000, %edi 1: popl %eax /* Install .text and .data to temporary area in high memory, * prior to reading the E820 memory map and relocating * properly. */ progress " .textdata\n" pushl %edi movl $_textdata_filesz, %ecx movl $_textdata_memsz, %edx call install_block popl %edi /* Initialise librm at current location */ progress " init_librm\n" movw %ax, (init_librm_vector+2) lcall *init_librm_vector /* Call relocate() to determine target address for relocation. * relocate() will return with %esi, %edi and %ecx set up * ready for the copy to the new location. */ progress " relocate\n" movw %ax, (prot_call_vector+2) pushl $relocate lcall *prot_call_vector popl %edx /* discard */ /* Copy code to new location */ progress " copy\n" pushl %edi pushw %bx movw $copy_bytes, %bx call process_bytes popw %bx popl %edi /* Initialise librm at new location */ progress " init_librm\n" lcall *init_librm_vector #endif /* Close access to payload */ progress " close_payload\n" movw %ax, (close_payload_vector+2) lcall *close_payload_vector /* Restore registers */ popw %es popw %ds popal ret .size install_prealloc, . - install_prealloc /* Vectors for far calls to .text16 functions. Must be in * .data16, since .prefix may not be writable. */ .section ".data16", "aw", @progbits #ifdef KEEP_IT_REAL init_libkir_vector: .word init_libkir .word 0 .size init_libkir_vector, . - init_libkir_vector #else init_librm_vector: .word init_librm .word 0 .size init_librm_vector, . - init_librm_vector prot_call_vector: .word prot_call .word 0 .size prot_call_vector, . - prot_call_vector #endif close_payload_vector: .word close_payload .word 0 .size close_payload_vector, . - close_payload_vector /* Payload address */ .section ".prefix.lib", "awx", @progbits payload_lma: .long 0 .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */ .ascii "ADHL" .long payload_lma .long 1 .long 0 .previous /* Dummy routines to open and close payload */ .section ".text16.early.data", "aw", @progbits .weak open_payload .weak close_payload open_payload: close_payload: clc lret .size open_payload, . - open_payload .size close_payload, . - close_payload /**************************************************************************** * uninstall * * Uninstall all text and data segments. * * Parameters: * %ax : .text16 segment address * %bx : .data16 segment address * Returns: * none * Corrupts: * none **************************************************************************** */ .section ".text16", "ax", @progbits .code16 .globl uninstall uninstall: call free_basemem ret .size uninstall, . - uninstall /* File split information for the compressor */ #if COMPRESS #define PACK_OR_COPY "PACK" #else #define PACK_OR_COPY "COPY" #endif .section ".zinfo", "a", @progbits .ascii "COPY" .long _prefix_lma .long _prefix_filesz .long _max_align .ascii PACK_OR_COPY .long _text16_early_lma .long _text16_early_filesz .long _max_align .ascii "PAYL" .long 0 .long 0 .long _max_align .ascii PACK_OR_COPY .long _text16_late_lma .long _text16_late_filesz .long _max_align .ascii PACK_OR_COPY .long _data16_lma .long _data16_filesz .long _max_align .ascii PACK_OR_COPY .long _textdata_lma .long _textdata_filesz .long _max_align