generic.ld

/* generic.ld -- parameterized linker script */
/* Copyright (c) 2021 Renaud Fivet           */

/* Linker script to configure memory regions. 
 * Need modifying for a specific board. 
 *   FLASH.ORIGIN: starting address of flash
 *   FLASH.LENGTH: length of flash
 *   RAM.ORIGIN: starting address of RAM bank 0
 *   RAM.LENGTH: length of RAM bank 0
 */
MEMORY
{
/* FLASH means code, read only data and data initialization */
	FLASH (rx) : ORIGIN = DEFINED(FLASHSTART) ? FLASHSTART : 0x08000000,
		LENGTH =  DEFINED(FLASHSIZE) ? FLASHSIZE : 16K
	RAM  (rwx) : ORIGIN = DEFINED(RAMSTART) ? RAMSTART : 0x20000000,
		LENGTH =  DEFINED(RAMSIZE) ? RAMSIZE : 4K
}

/* Linker script to place sections and symbol values. Should be used together
 * with other linker script that defines memory regions FLASH and RAM.
 * It references following symbols, which must be defined in code:
 *   Reset_Handler : Entry of reset handler
 * 
 * It defines following symbols, which code can use without definition:
 *   __exidx_start
 *   __exidx_end
 *   __copy_table_start__
 *   __copy_table_end__
 *   __zero_table_start__
 *   __zero_table_end__
 *   __etext
 *   __data_start__
 *   __preinit_array_start
 *   __preinit_array_end
 *   __init_array_start
 *   __init_array_end
 *   __fini_array_start
 *   __fini_array_end
 *   __data_end__
 *   __bss_start__
 *   __bss_end__
 *   __end__
 *   end
 *   __HeapLimit
 *   __StackLimit
 *   __StackTop
 *   __stack
 */
ENTRY(Reset_Handler)

SECTIONS
{
	.text :
	{
		KEEP(*(.isr_vector))
		*(.text*)

		*(.init)
		*(.fini)

		/* .ctors */
		*crtbegin.o(.ctors)
		*crtbegin?.o(.ctors)
		*(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
		*(SORT(.ctors.*))
		*(.ctors)

		/* .dtors */
 		*crtbegin.o(.dtors)
 		*crtbegin?.o(.dtors)
 		*(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
 		*(SORT(.dtors.*))
 		*(.dtors)

		*(.rodata*)

		*(.eh_frame*)
	} > FLASH

	.ARM.extab : 
	{
		*(.ARM.extab* .gnu.linkonce.armextab.*)
	} > FLASH

	__exidx_start = .;
	.ARM.exidx :
	{
		*(.ARM.exidx* .gnu.linkonce.armexidx.*)
	} > FLASH
	__exidx_end = .;

	/* To copy multiple ROM to RAM sections,
	 * uncomment .copy.table section and,
	 * define __STARTUP_COPY_MULTIPLE in startup_ARMCMx.S */
	/*
	.copy.table :
	{
		. = ALIGN(4);
		__copy_table_start__ = .;
		LONG (__etext)
		LONG (__data_start__)
		LONG (__data_end__ - __data_start__)
		LONG (__etext2)
		LONG (__data2_start__)
		LONG (__data2_end__ - __data2_start__)
		__copy_table_end__ = .;
	} > FLASH
	*/

	/* To clear multiple BSS sections,
	 * uncomment .zero.table section and,
	 * define __STARTUP_CLEAR_BSS_MULTIPLE in startup_ARMCMx.S */
	/*
	.zero.table :
	{
		. = ALIGN(4);
		__zero_table_start__ = .;
		LONG (__bss_start__)
		LONG (__bss_end__ - __bss_start__)
		LONG (__bss2_start__)
		LONG (__bss2_end__ - __bss2_start__)
		__zero_table_end__ = .;
	} > FLASH
	*/

	/* Location counter can end up 2byte aligned with narrow Thumb code but
	   __etext is assumed by startup code to be the LMA of a section in RAM
	   which must be 4byte aligned */
	__etext = ALIGN (4);

	/* In RAM isr vector reserved space at beginning of RAM */
	.isrdata (NOLOAD):
	{
		KEEP(*(.ram_vector))
	} > RAM

	.data : AT (__etext)
	{
		__data_start__ = .;
		*(vtable)
		*(.data*)

		. = ALIGN(4);
		/* preinit data */
		PROVIDE_HIDDEN (__preinit_array_start = .);
		*(.preinit_array)
		PROVIDE_HIDDEN (__preinit_array_end = .);

		. = ALIGN(4);
		/* init data */
		PROVIDE_HIDDEN (__init_array_start = .);
		*(SORT(.init_array.*))
		*(.init_array)
		PROVIDE_HIDDEN (__init_array_end = .);


		. = ALIGN(4);
		/* finit data */
		PROVIDE_HIDDEN (__fini_array_start = .);
		*(SORT(.fini_array.*))
		*(.fini_array)
		PROVIDE_HIDDEN (__fini_array_end = .);

		*(.jcr)
		. = ALIGN(4);
		/* All data end */
		__data_end__ = .;

	} > RAM

	.bss :
	{
		. = ALIGN(4);
		__bss_start__ = .;
		*(.bss*)
		*(COMMON)
		. = ALIGN(4);
		__bss_end__ = .;
	} > RAM
	
	.heap (COPY):
	{
		__end__ = .;
		PROVIDE(end = .);
		*(.heap*)
		__HeapLimit = .;
	} > RAM

	/* .stack_dummy section doesn't contains any symbols. It is only
	 * used for linker to calculate size of stack sections, and assign
	 * values to stack symbols later */
	.stack_dummy (COPY):
	{
		*(.stack*)
	} > RAM

	.crc __etext + SIZEOF(.data) :
	{
		KEEP(*(.crc_chk))
	} > FLASH

	/* Set stack top to end of RAM, and stack limit move down by
	 * size of stack_dummy section */
	__StackTop = ORIGIN(RAM) + LENGTH(RAM);
	__StackLimit = __StackTop - SIZEOF(.stack_dummy);
	PROVIDE(__stack = __StackTop);
	PROVIDE(__data_size = __bss_start__ - __data_start__);
	PROVIDE(__bss_size = __bss_end__ - __bss_start__);

	/* Check if data + heap + stack exceeds RAM limit */
	ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
}

/* end of generic.ld */