diff options
Diffstat (limited to 'c/src/lib/libbsp/i386/i386ex/startup/linkcmds')
| -rw-r--r-- | c/src/lib/libbsp/i386/i386ex/startup/linkcmds | 160 |
1 files changed, 122 insertions, 38 deletions
diff --git a/c/src/lib/libbsp/i386/i386ex/startup/linkcmds b/c/src/lib/libbsp/i386/i386ex/startup/linkcmds index 2834cbeafb..24202aa59c 100644 --- a/c/src/lib/libbsp/i386/i386ex/startup/linkcmds +++ b/c/src/lib/libbsp/i386/i386ex/startup/linkcmds @@ -17,60 +17,112 @@ ENTRY(reset) ; SECTIONS { - _rom_ints = 0x3fb0000; - .ints 0x0100 : - AT ( _rom_ints ) /* was 0x3fb3300 */ + +/******************************************************************************* + * Interrupts section: + * + * This section defines the layout of the interrupts in ROM ( VMA ) as well as their + * location in RAM (LMA). The _rom_ and _ram_ variables are used in start.s + * in order for the code to move the interrupt vector tables from ROM to RAM + * while still running in real-mode. The tables are moved from ROM, as the IDT + * is initialized with only 16-bit offsets for the interrupt handlers. + * This is purely an implementation issue. If you prefer the interrupt handlers + * to be resident in flash, then you must provide the code to create the interrupt + * gates with full 32bit offsets. The code in the current start.s does NOT support + * interrupts in ROM by merely redefining their location. + ******************************************************************************/ + _rom_ints = 0x3ff0000; /* was 0x3fb0000 */ + _rom_ints_segment = 0xF000 ; + _rom_ints_offset = 0x0000 ; + + _ram_ints_segment = 0x0000 ; + _ram_ints_offset = 0x0100 ; + + + .ints _ram_ints_offset : + AT ( _rom_ints ) { _sints = .; *(.ints); _eints = ALIGN (0x010); } - _cs4_ints_segment = 0x0010 ; - _cs4_ints_offset = 0x0000 ; - _cs6_t_ints_segment = 0xF000 ; /* was 0xF000 */ - _cs6_t_ints_offset = 0x0000 ; /* was 0x3300 */ - _cs6_t_ints_size = _eints - _sints ; - - _rom_gdt = _rom_ints + _cs6_t_ints_size; - .gdt 0x1000 : + + _ints_size = _eints - _sints ; +/************************************************************************************** + * GDT section: + * + * This section defines the locations of the GDT in ROM as well as in RAM. The _rom_ and + * _ram_ variables are used by start.s to copy the GDT from ROM to RAM when still in + * real-mode. The move from ROM to RAM is made as a writeable GDT is required for the + * jump to protected mode to be successful. + **************************************************************************************/ + + _rom_gdt = _rom_ints + _ints_size; + _rom_gdt_segment = 0xF000; + _rom_gdt_offset = _rom_ints_offset + _ints_size; + + _ram_gdt_segment = 0x0000 ; + _ram_gdt_offset = _ram_ints_offset + _ints_size; + + .gdt _ram_gdt_offset : AT ( _rom_gdt ) { _sgdt = .; *(.gdt); _egdt = ALIGN (0x10); } - _cs4_gdt_segment = 0x0100 ; /* evaluates to 0x1000 */ - _cs4_gdt_offset = 0x0000 ; - _cs6_t_gdt_segment = 0xF000; - _cs6_t_gdt_offset = _cs6_t_ints_size; /* was 0x0 */ - _cs6_t_gdt_size = _egdt - _sgdt; - - _rom_idt = _rom_gdt + _cs6_t_gdt_size + _cs6_t_ints_size ; - .idt 0x1200 : + _gdt_size = _egdt - _sgdt; + +/***************************************************************************************** + * IDT section: + * + * This section defines the locations of the IDT in ROM as well as in RAM. The _rom_ and + * _ram_ variables are used by start.s to copy the IDT from ROM to RAM when still in real-mode. + * The move from ROM to RAM is required to enable RTEMS to hook the interrupts, however, + * this move could be made when in protected mode. + ****************************************************************************************/ + + _rom_idt = _rom_gdt + _gdt_size ; + _rom_idt_segment = 0xF000 ; + _rom_idt_offset = _rom_gdt_offset + _gdt_size ; + + _ram_idt_segment = 0x0000 ; + _ram_idt_offset = _ram_gdt_offset + _gdt_size ; + + .idt _ram_idt_offset : AT ( _rom_idt ) { _sidt = .; *(.idt); _eidt = ALIGN (0x10); } - _cs4_idt_segment = 0x0120; - _cs4_idt_offset = 0x0000 ; - _cs6_t_idt_segment = 0xF000 ; - _cs6_t_idt_offset = _cs6_t_ints_size + _cs6_t_gdt_size ; /* was 0x1000 */ - _cs6_t_idt_size = _eidt - _sidt; - - _rom_data_start = _rom_idt + _cs6_t_idt_size ; - .data : - AT ( _rom_data_start ) /* was 0x3fd0000 */ + _idt_size = _eidt - _sidt; + +/**************************************************************************************** + * data section: + * + * This section defines the locations of the data section in ROM as well as in RAM. + * start.s copies the data section to RAM when in protected mode. + ***********************************************************************************/ + + _rom_data_start = _rom_idt + _idt_size ; + + .data : + AT ( _rom_data_start ) { _sdata = .; *(.data); _edata = ALIGN( 0x10 ) ; } _data_start = ADDR(.data) ; + data_start = _data_start ; _data_size = _edata - _sdata ; - _edata = _data_start + _data_size ; +/************************************************************************************** + * bss section: + * + * The bss section is the last section in RAM. + *************************************************************************************/ .bss : { _bss_start = .; @@ -81,11 +133,29 @@ SECTIONS _end = end; __end = end; } - _bss_size = _ebss - _bss_start ; + _bss_size = _ebss - _bss_start ; - +/************************************************************************************** + * General variables: + * + * The stack_size variable is customizable here. The heap is located directly after + * The stack in RAM. A routine within bspstart.c uses these variables to ensure that + * the heap used by RTEMS is as large as the RAM remaining after all workspace configurations + * are complete. + *************************************************************************************/ + stack_size = 0x1000 ; + stack_origin = end + stack_size ; + heap_bottom = stack_origin + 4 ; + +/*************************************************************************************** + * text section: + * + * This section is NOT copied into RAM. It is left in ROM, as the flash ROM is quick enough. + ***************************************************************************************/ .text ( 0x3f80000 ): { + CREATE_OBJECT_SYMBOLS + text_start = . ; _text_start = . ; *(.text ) ; . = ALIGN (16); @@ -101,24 +171,38 @@ SECTIONS *(.ctors) LONG(0) __CTOR_END__ = .; + . = ALIGN (4) ; __DTOR_LIST__ = .; LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2) *(.dtors) LONG(0) __DTOR_END__ = .; - _etext = ALIGN( 0x10 ); + _etext = ALIGN( 0x10 ); + _endtext = . ; } - .initial 0x3ff1000: +/******************************************************************************************* + * initial section: + * + * This section is defined after the data section. It must be in the top 64K of memory + * to enable the initial short jmp from the reset section while still in real-mode. It + * contains ALL initialization and data movement directives. + ******************************************************************************************/ + + .initial _rom_data_start + _data_size : { *(.initial); } - .reset 0x3fffff0: +/******************************************************************************************* + * reset section: + * + * This section contains the short jmp from the reset section to the initial section. It is + * the first code executed on reset/power on. + ******************************************************************************************/ + + .reset 0x3fffff0: { *(.reset); } -} - - - +}
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