diff options
Diffstat (limited to 'src/arch/i386/prefix/libprefix.S')
| -rw-r--r-- | src/arch/i386/prefix/libprefix.S | 401 |
1 files changed, 265 insertions, 136 deletions
diff --git a/src/arch/i386/prefix/libprefix.S b/src/arch/i386/prefix/libprefix.S index 12cf9184d..deea5ab30 100644 --- a/src/arch/i386/prefix/libprefix.S +++ b/src/arch/i386/prefix/libprefix.S @@ -17,6 +17,10 @@ * */ + .arch i386 + .section ".prefix.lib", "awx", @progbits + .section ".data16", "aw", @progbits + /** * High memory temporary load address * @@ -27,24 +31,125 @@ * We use the start of an even megabyte so that we don't have to worry * about the current state of the A20 line. * - * We use 4MB rather than 2MB because there is at least one commercial - * PXE ROM ("Broadcom UNDI, PXE-2.1 (build 082) v2.0.4") which stores - * data required by the UNDI ROM loader (yes, the ROM loader; that's - * the component which should be impossible to damage short of - * screwing with the MMU) around the 2MB mark. Sadly, this is not a - * joke. - * + * We use 4MB rather than 2MB because some PXE stack / PMM BIOS + * combinations are known to place data required by other UNDI ROMs + * loader around the 2MB mark. */ -#define HIGHMEM_LOADPOINT ( 4 << 20 ) + .globl HIGHMEM_LOADPOINT + .equ HIGHMEM_LOADPOINT, ( 4 << 20 ) /* Image compression enabled */ #define COMPRESS 1 #define CR0_PE 1 - .arch i386 - .section ".prefix.lib", "awx", @progbits - .section ".data16", "aw", @progbits +/***************************************************************************** + * Utility function: print character (with LF -> LF,CR translation) + * + * Parameters: + * %al : character to print + * Returns: + * Nothing + * Corrupts: + * %ax + ***************************************************************************** + */ + .section ".prefix.lib" + .code16 + .globl print_character +print_character: + /* Preserve registers */ + pushw %bx + pushw %bp + /* Print character */ + movw $0x0007, %bx /* page 0, attribute 7 (normal) */ + movb $0x0e, %ah /* write char, tty mode */ + cmpb $0x0a, %al /* '\n'? */ + jne 1f + int $0x10 + movb $0x0d, %al +1: int $0x10 + /* Restore registers and return */ + popw %bp + popw %bx + ret + .size print_character, . - print_character + +/***************************************************************************** + * Utility function: print a NUL-terminated string + * + * Parameters: + * %ds:si : string to print + * Returns: + * %ds:si : character after terminating NUL + ***************************************************************************** + */ + .section ".prefix.lib" + .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 + * Returns: + * Nothing + ***************************************************************************** + */ + .section ".prefix.lib" + .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 <norbert.juffa@amd.com> */ + 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 /**************************************************************************** * pm_call (real-mode near call) @@ -70,13 +175,14 @@ #ifndef KEEP_IT_REAL /* GDT for protected-mode calls */ - .section ".data16" + .section ".prefix.lib" .align 16 +pm_call_vars: gdt: gdt_limit: .word gdt_length - 1 gdt_base: .long 0 .word 0 /* padding */ -pm_cs: /* 16-bit protected-mode code segment */ +pm_cs: /* 16-bit protected-mode code segment */ .equ PM_CS, pm_cs - gdt .word 0xffff, 0 .byte 0, 0x9b, 0x00, 0 @@ -92,18 +198,24 @@ gdt_end: .equ gdt_length, . - gdt .size gdt, . - gdt - .section ".data16" + .section ".prefix.lib" .align 16 pm_saved_gdt: .long 0, 0 .size pm_saved_gdt, . - pm_saved_gdt + .equ pm_call_vars_size, . - pm_call_vars +#define PM_CALL_VAR(x) ( -pm_call_vars_size + ( (x) - pm_call_vars ) ) + .section ".prefix.lib" .code16 pm_call: - /* Preserve registers, flags, GDT, and RM return point */ + /* Preserve registers, flags, and RM return point */ + pushw %bp + movw %sp, %bp + subw $pm_call_vars_size, %sp + andw $0xfff0, %sp pushfl - sgdt pm_saved_gdt pushw %gs pushw %fs pushw %es @@ -112,27 +224,43 @@ pm_call: pushw %cs pushw $99f + /* Set up local variable block, and preserve GDT */ + pushw %cx + pushw %si + pushw %di + pushw %ss + popw %es + movw $pm_call_vars, %si + leaw PM_CALL_VAR(pm_call_vars)(%bp), %di + movw $pm_call_vars_size, %cx + cs rep movsb + popw %di + popw %si + popw %cx + sgdt PM_CALL_VAR(pm_saved_gdt)(%bp) + /* Set up GDT bases */ pushl %eax - pushw %bx + pushl %edi xorl %eax, %eax - movw %ds, %ax + movw %ss, %ax shll $4, %eax - addl $gdt, %eax - movl %eax, gdt_base + movzwl %bp, %edi + leal PM_CALL_VAR(gdt)(%eax, %edi), %eax + movl %eax, PM_CALL_VAR(gdt_base)(%bp) movw %cs, %ax - movw $pm_cs, %bx + movw $PM_CALL_VAR(pm_cs), %di call set_seg_base movw %ss, %ax - movw $pm_ss, %bx + movw $PM_CALL_VAR(pm_ss), %di call set_seg_base - popw %bx + popl %edi popl %eax /* Switch CPU to protected mode and load up segment registers */ pushl %eax cli - lgdt gdt + lgdt PM_CALL_VAR(gdt)(%bp) movl %cr0, %eax orb $CR0_PE, %al movl %eax, %cr0 @@ -168,18 +296,19 @@ pm_call: popw %es popw %fs popw %gs - lgdt pm_saved_gdt + lgdt PM_CALL_VAR(pm_saved_gdt)(%bp) popfl - + movw %bp, %sp + popw %bp ret .size pm_call, . - pm_call set_seg_base: rolw $4, %ax - movw %ax, 2(%bx) - andw $0xfff0, 2(%bx) - movb %al, 4(%bx) - andb $0x0f, 4(%bx) + movw %ax, 2(%bp,%di) + andw $0xfff0, 2(%bp,%di) + movb %al, 4(%bp,%di) + andb $0x0f, 4(%bp,%di) ret .size set_seg_base, . - set_seg_base @@ -196,7 +325,7 @@ set_seg_base: * %ecx : length * Returns: * %ds:esi : next source address - * %ds:esi : next destination address + * %es:edi : next destination address * Corrupts: * None **************************************************************************** @@ -211,24 +340,57 @@ copy_bytes: .size copy_bytes, . - copy_bytes /**************************************************************************** - * install_block (real-mode or 16-bit protected-mode near call) + * install_block (real-mode near call) * * Install block to specified address * * Parameters: - * %ds:esi : source address (must be a multiple of 16) - * %es:edi : destination address + * %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: - * %ds:esi : next source address (will be a multiple of 16) + * %esi : next source physical address (will be a multiple of 16) * Corrupts: - * %edi, %ecx, %edx + * none **************************************************************************** */ .section ".prefix.lib" .code16 install_block: + +#ifdef KEEP_IT_REAL + + /* Preserve registers */ + pushw %ds + pushw %es + pushl %ecx + pushl %edi + + /* Convert %esi and %edi to segment registers */ + shrl $4, %esi + movw %si, %ds + xorw %si, %si + shrl $4, %edi + movw %di, %es + xorw %di, %di + +#else /* KEEP_IT_REAL */ + + /* Call self in protected mode */ + pushw %ax + movw $1f, %ax + call pm_call + popw %ax + ret +1: + /* Preserve registers */ + pushl %ecx + pushl %edi + +#endif /* KEEP_IT_REAL */ + + #if COMPRESS /* Decompress source to destination */ call decompress16 @@ -249,6 +411,28 @@ install_block: addl $0xf, %esi andl $~0xf, %esi + +#ifdef KEEP_IT_REAL + + /* Convert %ds:esi back to a physical address */ + movzwl %ds, %cx + shll $4, %ecx + addl %ecx, %esi + + /* Restore registers */ + popl %edi + popl %ecx + popw %es + popw %ds + +#else /* KEEP_IT_REAL */ + + /* Restore registers */ + popl %edi + popl %ecx + +#endif + ret .size install_block, . - install_block @@ -270,6 +454,7 @@ install_block: */ .section ".prefix.lib" .code16 + .globl alloc_basemem alloc_basemem: /* FBMS => %ax as segment address */ movw $0x40, %ax @@ -296,137 +481,86 @@ alloc_basemem: .size alloc_basemem, . - alloc_basemem /**************************************************************************** - * install_basemem (real-mode near call) + * install (real-mode near call) * - * Install source block into base memory + * Install all text and data segments. * * Parameters: - * %esi : source physical address (must be a multiple of 16) - * %es : destination segment address - * %cx : length of (decompressed) data - * %dx : total length of block (including any uninitialised data portion) + * none * Returns: - * %esi : next source physical address (will be a multiple of 16) + * %ax : .text16 segment address + * %bx : .data16 segment address * Corrupts: - * %edi, %ecx, %edx + * none **************************************************************************** */ .section ".prefix.lib" .code16 -install_basemem: + .globl install +install: /* Preserve registers */ - pushw %ds - - /* Preserve original %esi */ pushl %esi - - /* Install to specified address */ - shrl $4, %esi - movw %si, %ds - xorw %si, %si - xorl %edi, %edi - movzwl %cx, %ecx - movzwl %dx, %edx - call install_block - - /* Fix up %esi for return */ - popl %ecx - addl %ecx, %esi - - /* Restore registers */ - popw %ds + pushl %edi + /* Allocate space for .text16 and .data16 */ + call alloc_basemem + /* Image source = %cs:0000 */ + xorl %esi, %esi + /* Image destination = HIGHMEM_LOADPOINT */ + movl $HIGHMEM_LOADPOINT, %edi + /* Install text and data segments */ + call install_prealloc + /* Restore registers and return */ + popl %edi + popl %esi ret - .size install_basemem, . - install_basemem - -/**************************************************************************** - * install_highmem (real-mode near call) - * - * Install source block into high memory - * - * Parameters: - * %esi : source physical address (must be a multiple of 16) - * %edi : destination physical address - * %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) - * Corrupts: - * %edi, %ecx, %edx - **************************************************************************** - */ - -#ifndef KEEP_IT_REAL - - .section ".prefix.lib" - .code16 -install_highmem: - /* Preserve registers */ - pushw %ax - - /* Install to specified address */ - movw $install_block, %ax - call pm_call + .size install, . - install - /* Restore registers */ - popw %ax - ret - .size install_highmem, . - install_highmem - -#endif /* KEEP_IT_REAL */ - /**************************************************************************** - * install (real-mode near call) * install_prealloc (real-mode near call) * * Install all text and data segments. * * Parameters: - * %ax : .text16 segment address (install_prealloc only) - * %bx : .data16 segment address (install_prealloc only) - * Returns: - * %ax : .text16 segment address - * %bx : .data16 segment address - * %edi : .text physical address (if applicable) + * %ax : .text16 segment address + * %bx : .data16 segment address + * %esi : Image source physical address (or zero for %cs:0000) + * %edi : Decompression temporary area physical address * Corrupts: * none **************************************************************************** */ .section ".prefix.lib" .code16 - .globl install -install: - /* Allocate space for .text16 and .data16 */ - call alloc_basemem - .size install, . - install .globl install_prealloc install_prealloc: /* Save registers */ + pushal pushw %ds pushw %es - pushl %esi - pushl %ecx - pushl %edx /* Sanity: clear the direction flag asap */ cld /* Calculate physical address of payload (i.e. first source) */ - xorl %esi, %esi + testl %esi, %esi + jnz 1f movw %cs, %si shll $4, %esi - addl $_payload_offset, %esi - - /* Install .text16 */ - movw %ax, %es - movw $_text16_size, %cx - movw %cx, %dx - call install_basemem +1: addl $_payload_offset, %esi - /* Install .data16 */ - movw %bx, %es - movw $_data16_progbits_size, %cx - movw $_data16_size, %dx - call install_basemem + /* Install .text16 and .data16 */ + pushl %edi + movzwl %ax, %edi + shll $4, %edi + movl $_text16_size, %ecx + movl %ecx, %edx + call install_block /* .text16 */ + movzwl %bx, %edi + shll $4, %edi + movl $_data16_progbits_size, %ecx + movl $_data16_size, %edx + call install_block /* .data16 */ + popl %edi /* Set up %ds for access to .data16 */ movw %bx, %ds @@ -440,12 +574,9 @@ install_prealloc: * prior to reading the E820 memory map and relocating * properly. */ - movl $HIGHMEM_LOADPOINT, %edi movl $_textdata_progbits_size, %ecx movl $_textdata_size, %edx - pushl %edi - call install_highmem - popl %edi + call install_block /* Initialise librm at current location */ movw %ax, (init_librm_vector+2) @@ -473,11 +604,9 @@ install_prealloc: #endif /* Restore registers */ - popl %edx - popl %ecx - popl %esi popw %es popw %ds + popal ret .size install_prealloc, . - install_prealloc |