diff options
Diffstat (limited to 'ports/raspberrypi/link.ld')
| -rw-r--r-- | ports/raspberrypi/link.ld | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/ports/raspberrypi/link.ld b/ports/raspberrypi/link.ld new file mode 100644 index 000000000..d642fd680 --- /dev/null +++ b/ports/raspberrypi/link.ld @@ -0,0 +1,250 @@ +/* Based on GCC ARM embedded samples. + Defines the following symbols for use by code: + __exidx_start + __exidx_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 (== StackTop) +*/ + +MEMORY +{ + FLASH_FIRMWARE (rx) : ORIGIN = 0x10000000, LENGTH = 1024k + RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 256k + SCRATCH_X (rwx) : ORIGIN = 0x20040000, LENGTH = 4k + SCRATCH_Y (rwx) : ORIGIN = 0x20041000, LENGTH = 4k +} + +ENTRY(_entry_point) + +SECTIONS +{ + /* Second stage bootloader is prepended to the image. It must be 256 bytes big + and checksummed. It is usually built by the boot_stage2 target + in the Pico SDK + */ + + .flash_begin : { + __flash_binary_start = .; + } > FLASH_FIRMWARE + + .boot2 : { + __boot2_start__ = .; + KEEP (*(.boot2)) + __boot2_end__ = .; + } > FLASH_FIRMWARE + + ASSERT(__boot2_end__ - __boot2_start__ == 256, + "ERROR: Pico second stage bootloader must be 256 bytes in size") + + /* The second stage will always enter the image at the start of .text. + The debugger will use the ELF entry point, which is the _entry_point + symbol if present, otherwise defaults to start of .text. + This can be used to transfer control back to the bootrom on debugger + launches only, to perform proper flash setup. + */ + + .text : { + __reset_start = .; + KEEP (*(.reset)) + . = ALIGN(256); + __reset_end = .; + ASSERT(__reset_end - __reset_start == 256, "ERROR: reset section should only be 256 bytes"); + KEEP (*(.vectors)) + /* TODO revisit this now memset/memcpy/float in ROM */ + /* bit of a hack right now to exclude all floating point and time critical (e.g. memset, memcpy) code from + * FLASH ... we will include any thing excluded here in .data below by default */ + *(.init) + *(EXCLUDE_FILE(*libgcc.a: *libc.a:*lib_a-mem*.o *libm.a:) .text*) + *(.fini) + /* Pull all c'tors into .text */ + *crtbegin.o(.ctors) + *crtbegin?.o(.ctors) + *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors) + *(SORT(.ctors.*)) + *(.ctors) + /* Followed by destructors */ + *crtbegin.o(.dtors) + *crtbegin?.o(.dtors) + *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors) + *(SORT(.dtors.*)) + *(.dtors) + + *(.eh_frame*) + . = ALIGN(4); + } > FLASH_FIRMWARE + + .rodata : { + *(EXCLUDE_FILE(*libgcc.a: *libc.a:*lib_a-mem*.o *libm.a:) .rodata*) + . = ALIGN(4); + *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.flashdata*))) + . = ALIGN(4); + } > FLASH_FIRMWARE + + .ARM.extab : + { + *(.ARM.extab* .gnu.linkonce.armextab.*) + } > FLASH_FIRMWARE + + __exidx_start = .; + .ARM.exidx : + { + *(.ARM.exidx* .gnu.linkonce.armexidx.*) + } > FLASH_FIRMWARE + __exidx_end = .; + + /* Machine inspectable binary information */ + . = ALIGN(4); + __binary_info_start = .; + .binary_info : + { + KEEP(*(.binary_info.keep.*)) + *(.binary_info.*) + } > FLASH_FIRMWARE + __binary_info_end = .; + . = ALIGN(4); + + /* End of .text-like segments */ + __etext = .; + + .ram_vector_table (COPY): { + *(.ram_vector_table) + } > RAM + + .data : { + __data_start__ = .; + *(vtable) + + *(.time_critical*) + + /* remaining .text and .rodata; i.e. stuff we exclude above because we want it in RAM */ + *(.text*) + . = ALIGN(4); + *(.rodata*) + . = ALIGN(4); + + *(.data*) + + . = ALIGN(4); + *(.after_data.*) + . = ALIGN(4); + /* preinit data */ + PROVIDE_HIDDEN (__mutex_array_start = .); + KEEP(*(SORT(.mutex_array.*))) + KEEP(*(.mutex_array)) + PROVIDE_HIDDEN (__mutex_array_end = .); + + . = ALIGN(4); + /* preinit data */ + PROVIDE_HIDDEN (__preinit_array_start = .); + KEEP(*(SORT(.preinit_array.*))) + KEEP(*(.preinit_array)) + PROVIDE_HIDDEN (__preinit_array_end = .); + + . = ALIGN(4); + /* init data */ + PROVIDE_HIDDEN (__init_array_start = .); + KEEP(*(SORT(.init_array.*))) + KEEP(*(.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 AT> FLASH_FIRMWARE + + .uninitialized_data (COPY): { + . = ALIGN(4); + *(.uninitialized_data*) + } > RAM + + /* Start and end symbols must be word-aligned */ + .scratch_x : { + __scratch_x_start__ = .; + *(.scratch_x.*) + . = ALIGN(4); + __scratch_x_end__ = .; + } > SCRATCH_X AT > FLASH_FIRMWARE + __scratch_x_source__ = LOADADDR(.scratch_x); + + .scratch_y : { + __scratch_y_start__ = .; + *(.scratch_y.*) + . = ALIGN(4); + __scratch_y_end__ = .; + } > SCRATCH_Y AT > FLASH_FIRMWARE + __scratch_y_source__ = LOADADDR(.scratch_y); + + .bss : { + . = ALIGN(4); + __bss_start__ = .; + *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.bss*))) + *(COMMON) + . = ALIGN(4); + __bss_end__ = .; + } > RAM + + .heap (COPY): + { + __end__ = .; + end = __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 + * + * stack1 section may be empty/missing if platform_launch_core1 is not used */ + + /* by default we put core 0 stack at the end of scratch Y, so that if core 1 + * stack is not used then all of SCRATCH_X is free. + */ + .stack1_dummy (COPY): + { + *(.stack1*) + } > SCRATCH_X + .stack_dummy (COPY): + { + *(.stack*) + } > SCRATCH_Y + + .flash_end : { + __flash_binary_end = .; + } > FLASH_FIRMWARE + + /* stack limit is poorly named, but historically is maximum heap ptr */ + __StackLimit = ORIGIN(RAM) + LENGTH(RAM); + __StackOneTop = ORIGIN(SCRATCH_X) + LENGTH(SCRATCH_X); + __StackTop = ORIGIN(SCRATCH_Y) + LENGTH(SCRATCH_Y); + __StackOneBottom = __StackOneTop - SIZEOF(.stack1_dummy); + __StackBottom = __StackTop - SIZEOF(.stack_dummy); + PROVIDE(__stack = __StackTop); + + /* Check if data + heap + stack exceeds RAM limit */ + ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed") + /* todo assert on extra code */ +} |