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Create two easy-to-use entry points in libprefix: install and
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install_prealloc.  I *think* these will suffice for all the 16-bit
prefixes.
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Michael Brown committed May 2, 2006
1 parent 9e1dd64 commit 10c28a5
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Showing 4 changed files with 122 additions and 35 deletions.
9 changes: 1 addition & 8 deletions src/arch/i386/prefix/dskprefix.S
View file
Expand Up @@ -348,21 +348,14 @@ msg1end:
.word 0xAA55

start_runtime:
/* Install .text16 and .data16 to top of base memory */
call alloc_basemem
call install_basemem

/* Install .text and .data to 2MB mark */
movl $(2<<20), %edi
call install_highmem
call install

/* Jump to .text16 segment */
pushw %ax
pushw $1f
lret
.section ".text16", "awx", @progbits
1:
call init_gdt
pushl $initialise
data32 call prot_call
popl %eax /* discard */
Expand Down
109 changes: 99 additions & 10 deletions src/arch/i386/prefix/libprefix.S
View file
Expand Up @@ -30,19 +30,20 @@
* Parameters:
* %esi : byte offset within loaded image (must be a multiple of 16)
* %es:edi : destination address
* %ecx : length to install
* %ecx : length of (decompressed) data
* %edx : total length of block (including any uninitialised data portion)
* Returns:
* none
* Corrupts:
* %esi, %edi, %ecx
* %esi, %edi, %ecx, %edx
****************************************************************************
*/
.section ".prefix.lib"
.code16
install_block:
/* Preserve registers */
pushw %ds
pushw %ax
pushw %eax

/* Starting segment => %ds */
movw %cs, %ax
Expand All @@ -51,12 +52,22 @@ install_block:
movw %ax, %ds
xorl %esi, %esi

/* Calculate start and length of uninitialised data portion */
leal (%edi,%ecx), %eax
subl %ecx, %edx

/* Do the copy */
cld
addr32 rep movsb /* or "call decompress16" */
rep addr32 movsb /* or "call decompress16" */

/* Zero remaining space */
movl %eax, %edi
movl %edx, %ecx
xorb %al, %al
rep addr32 stosb

/* Restore registers */
popw %ax
popw %eax
popw %ds
ret
.size install_block, . - install_block
Expand All @@ -79,7 +90,6 @@ install_block:
*/
.section ".prefix.lib"
.code16
.globl alloc_basemem
alloc_basemem:
/* FBMS => %ax as segment address */
movw $0x40, %ax
Expand Down Expand Up @@ -121,29 +131,32 @@ alloc_basemem:
*/
.section ".prefix.lib"
.code16
.globl install_basemem
install_basemem:
/* Preserve registers */
pushw %es
pushl %esi
pushl %edi
pushl %ecx
pushl %edx

/* Install .text16 */
movw %ax, %es
xorl %edi, %edi
movl $_text16_load_offset, %esi
movl $_text16_size, %ecx
movl %ecx, %edx
call install_block

/* Install .data16 */
movw %bx, %es
xorl %edi, %edi
movl $_data16_load_offset, %esi
movl $_data16_progbits_size, %ecx
movl $_data16_size, %edx
call install_block

/* Restore registers */
popl %edx
popl %ecx
popl %edi
popl %esi
Expand All @@ -160,6 +173,9 @@ install_basemem:
* simpler.
****************************************************************************
*/

#ifndef KEEP_IT_REAL

.section ".prefix.lib"
.align 16
gdt:
Expand All @@ -180,6 +196,8 @@ flat_ds: /* Flat real mode data segment */
gdt_end:
.equ gdt_length, gdt_end - gdt
.size gdt, . - gdt

#endif /* KEEP_IT_REAL */

/****************************************************************************
* set_segment_limits (real-mode near call)
Expand All @@ -190,6 +208,9 @@ gdt_end:
* %cx : Segment limit ($REAL_DS or $FLAT_DS)
****************************************************************************
*/

#ifndef KEEP_IT_REAL

.section ".prefix.lib"
.code16
set_segment_limits:
Expand Down Expand Up @@ -222,6 +243,8 @@ set_segment_limits:
ret
.size set_segment_limits, . - set_segment_limits

#endif /* KEEP_IT_REAL */

/****************************************************************************
* install_highmem (real-mode near call)
*
Expand All @@ -235,15 +258,18 @@ set_segment_limits:
* none
****************************************************************************
*/

#ifndef KEEP_IT_REAL

.section ".prefix.lib"
.code16
.globl install_highmem
install_highmem:
/* Preserve registers and interrupt status */
pushfl
pushl %esi
pushl %edi
pushl %ecx
pushl %edx

/* Disable interrupts and flatten real mode */
cli
Expand All @@ -253,18 +279,81 @@ install_highmem:
/* Install .text and .data to specified address */
xorw %cx, %cx
movw %cx, %es
movl $_text_load_offset, %esi
movl $_text_progbits_size, %ecx
movl $_textdata_load_offset, %esi
movl $_textdata_progbits_size, %ecx
movl $_textdata_size, %edx
call install_block

/* Unflatten real mode */
movw $REAL_DS, %cx
call set_segment_limits

/* Restore registers and interrupt status */
popl %edx
popl %ecx
popl %edi
popl %esi
popfl
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)
* 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:
/* Install .text16 and .data16 */
call install_basemem

#ifndef KEEP_IT_REAL
/* Install .text and .data to 2MB mark. Use 2MB to avoid
* problems with A20.
*/
movl $(2<<20), %edi
call install_highmem

/* Continue executing in .text16 segment */
pushw %cs
pushw $2f
pushw %ax
pushw $1f
lret
.section ".text16", "awx", @progbits
1:
/* Set up protected-mode GDT, call relocate(), reset GDT */
call init_gdt
pushl $relocate
data32 call prot_call
addw $4, %sp
call init_gdt

/* Return to executing in .prefix section */
lret
.section ".prefix.lib"
2:
#endif
ret
.size install_prealloc, . - install_prealloc
37 changes: 21 additions & 16 deletions src/arch/i386/scripts/i386.lds
View file
Expand Up @@ -20,7 +20,7 @@ SECTIONS {
* will default to:
*
* _prefix_link_addr = 0
* _text_link_addr = 0
* _textdata_link_addr = 0
* _load_addr = 0
* _max_align = 16
*
Expand Down Expand Up @@ -108,11 +108,14 @@ SECTIONS {
* The 32-bit sections
*/

_text_link_addr = DEFINED ( _text_link_addr ) ? _text_link_addr : 0;
. = _text_link_addr;
_textdata_link_addr = ( DEFINED ( _textdata_link_addr ) ?
_textdata_link_addr : 0 );
. = _textdata_link_addr;
_textdata = .;

_text = .;

.text : AT ( _text_load_offset + __text ) {
.text : AT ( _textdata_load_offset + __text ) {
__text = .;
*(.text)
*(.text.*)
Expand All @@ -122,34 +125,36 @@ SECTIONS {

_data = .;

.rodata : AT ( _text_load_offset + __rodata ) {
.rodata : AT ( _textdata_load_offset + __rodata ) {
__rodata = .;
*(.rodata)
*(.rodata.*)
}
.data : AT ( _text_load_offset + __data ) {
.data : AT ( _textdata_load_offset + __data ) {
__data = .;
*(.data)
*(.data.*)
*(SORT(.tbl.*)) /* Various tables. See include/tables.h */
_etext_progbits = .;
_etextdata_progbits = .;
}
.bss : AT ( _text_load_offset + __bss ) {
.bss : AT ( _textdata_load_offset + __bss ) {
__bss = .;
_bss = .;
*(.bss)
*(.bss.*)
*(COMMON)
_ebss = .;
}
.stack : AT ( _text_load_offset + __stack ) {
.stack : AT ( _textdata_load_offset + __stack ) {
__stack = .;
*(.stack)
*(.stack.*)
}

_edata = .;

_etextdata = .;

_end = .;

/*
Expand Down Expand Up @@ -194,12 +199,12 @@ SECTIONS {
_data16_progbits_size = _edata16_progbits - _data16;
. = _data16_load_addr + _data16_progbits_size;

. -= _text_link_addr;
_text_load_offset = ALIGN ( _max_align );
_text_load_addr = _text_link_addr + _text_load_offset;
_text_size = _etext - _text;
_text_progbits_size = _etext_progbits - _text;
. = _text_load_addr + _text_progbits_size;
. -= _textdata_link_addr;
_textdata_load_offset = ALIGN ( _max_align );
_textdata_load_addr = _textdata_link_addr + _textdata_load_offset;
_textdata_size = _etextdata - _textdata;
_textdata_progbits_size = _etextdata_progbits - _textdata;
. = _textdata_load_addr + _textdata_progbits_size;

. = ALIGN ( _max_align );

Expand All @@ -223,7 +228,7 @@ SECTIONS {
_assert = ASSERT ( ( . == ALIGN ( _max_align ) ),
"_data16 is badly aligned" );

. = _text_load_addr - _text_link_addr;
. = _textdata_load_addr - _textdata_link_addr;
_assert = ASSERT ( ( . == ALIGN ( _max_align ) ),
"_text is badly aligned" );

Expand Down
2 changes: 1 addition & 1 deletion src/arch/i386/transitions/librm.S
View file
Expand Up @@ -357,7 +357,7 @@ prot_call:
popw %gs
popal
popfl
ret
data32 ret

/****************************************************************************
* real_call (protected-mode near call, 32-bit virtual return address)
Expand Down

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