/* * Copyright 2020 The Pigweed Authors * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ /* This relatively simplified linker script will work with many ARMv7-M cores * that have on-board memory-mapped RAM and FLASH. For more complex projects and * devices, it's possible this linker script will not be sufficient as-is. * * This linker script is likely not suitable for a project with a bootloader. */ /* Provide useful error messages when required configurations are not set. */ #ifndef PW_BOOT_VECTOR_TABLE_BEGIN #error "PW_BOOT_VECTOR_TABLE_BEGIN is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_VECTOR_TABLE_BEGIN #ifndef PW_BOOT_VECTOR_TABLE_SIZE #error "PW_BOOT_VECTOR_TABLE_SIZE is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_VECTOR_TABLE_SIZE #ifndef PW_BOOT_FLASH_BEGIN #error "PW_BOOT_FLASH_BEGIN is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_FLASH_BEGIN #ifndef PW_BOOT_FLASH_SIZE #error "PW_BOOT_FLASH_SIZE is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_FLASH_SIZE #ifndef PW_BOOT_RAM_BEGIN #error "PW_BOOT_RAM_BEGIN is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_RAM_BEGIN #ifndef PW_BOOT_RAM_SIZE #error "PW_BOOT_RAM_SIZE is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_RAM_SIZE #ifndef PW_BOOT_HEAP_SIZE #error "PW_BOOT_HEAP_SIZE is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_HEAP_SIZE #ifndef PW_BOOT_MIN_STACK_SIZE #error "PW_BOOT_MIN_STACK_SIZE is not defined, and is required to use pw_boot_armv7m" #endif // PW_BOOT_MIN_STACK_SIZE /* Note: This technically doesn't set the firmware's entry point. Setting the * firmware entry point is done by setting vector_table[1] * (Reset_Handler). However, this DOES tell the compiler how to optimize * when --gc-sections is enabled. */ ENTRY(pw_boot_Entry) MEMORY { /* TODO(pwbug/57): Make it possible for projects to freely customize * memory regions. */ /* Vector Table (typically in flash) */ VECTOR_TABLE(rx) : \ ORIGIN = PW_BOOT_VECTOR_TABLE_BEGIN, \ LENGTH = PW_BOOT_VECTOR_TABLE_SIZE /* Internal Flash */ FLASH(rx) : \ ORIGIN = PW_BOOT_FLASH_BEGIN, \ LENGTH = PW_BOOT_FLASH_SIZE /* Internal SRAM */ RAM(rwx) : \ ORIGIN = PW_BOOT_RAM_BEGIN, \ LENGTH = PW_BOOT_RAM_SIZE } SECTIONS { /* This is the link-time vector table. If used, the VTOR (Vector Table Offset * Register) MUST point to this memory location in order to be used. This can * be done by ensuring this section exists at the default location of the VTOR * so it's used on reset, or by explicitly setting the VTOR in a bootloader * manually to point to &pw_boot_vector_table_addr before interrupts are enabled. */ .vector_table : ALIGN(512) { pw_boot_vector_table_addr = .; KEEP(*(.vector_table)) } >VECTOR_TABLE /* Main executable code. */ .code : ALIGN(8) { . = ALIGN(8); /* Application code. */ *(.text) *(.text*) KEEP(*(.init)) KEEP(*(.fini)) . = ALIGN(8); /* Constants.*/ *(.rodata) *(.rodata*) /* .preinit_array, .init_array, .fini_array are used by libc. * Each section is a list of function pointers that are called pre-main and * post-exit for object initialization and tear-down. * Since the region isn't explicitly referenced, specify KEEP to prevent * link-time garbage collection. SORT is used for sections that have strict * init/de-init ordering requirements. */ . = ALIGN(8); PROVIDE_HIDDEN(__preinit_array_start = .); KEEP(*(.preinit_array*)) PROVIDE_HIDDEN(__preinit_array_end = .); PROVIDE_HIDDEN(__init_array_start = .); KEEP(*(SORT(.init_array.*))) KEEP(*(.init_array*)) PROVIDE_HIDDEN(__init_array_end = .); PROVIDE_HIDDEN(__fini_array_start = .); KEEP(*(SORT(.fini_array.*))) KEEP(*(.fini_array*)) PROVIDE_HIDDEN(__fini_array_end = .); } >FLASH /* Used by unwind-arm/ */ .ARM : ALIGN(8) { __exidx_start = .; *(.ARM.exidx*) __exidx_end = .; } >FLASH /* Explicitly initialized global and static data. (.data)*/ .static_init_ram : ALIGN(8) { *(.data) *(.data*) . = ALIGN(8); } >RAM AT> FLASH /* Zero initialized global/static data. (.bss) * This section is zero initialized in pw_boot_Entry(). */ .zero_init_ram : ALIGN(8) { *(.bss) *(.bss*) *(COMMON) . = ALIGN(8); } >RAM .heap : ALIGN(8) { pw_boot_heap_low_addr = .; . = . + PW_BOOT_HEAP_SIZE; . = ALIGN(8); pw_boot_heap_high_addr = .; } >RAM /* Link-time check for stack overlaps. */ .stack (NOLOAD) : ALIGN(8) { /* Set the address that the main stack pointer should be initialized to. */ pw_boot_stack_low_addr = .; HIDDEN(_stack_size = ORIGIN(RAM) + LENGTH(RAM) - .); /* Align the stack to a lower address to ensure it isn't out of range. */ HIDDEN(_stack_high = (. + _stack_size) & ~0x7); ASSERT(_stack_high - . >= PW_BOOT_MIN_STACK_SIZE, "Error: Not enough RAM for desired minimum stack size."); . = _stack_high; pw_boot_stack_high_addr = .; } >RAM /* Discard unwind info. */ .ARM.extab 0x0 (INFO) : { KEEP(*(.ARM.extab*)) } } /* Symbols used by core_init.c: */ /* Start of .static_init_ram in FLASH. */ _pw_static_init_flash_start = LOADADDR(.static_init_ram); /* Region of .static_init_ram in RAM. */ _pw_static_init_ram_start = ADDR(.static_init_ram); _pw_static_init_ram_end = _pw_static_init_ram_start + SIZEOF(.static_init_ram); /* Region of .zero_init_ram. */ _pw_zero_init_ram_start = ADDR(.zero_init_ram); _pw_zero_init_ram_end = _pw_zero_init_ram_start + SIZEOF(.zero_init_ram); /* arm-none-eabi expects `end` symbol to point to start of heap for sbrk. */ PROVIDE(end = _pw_zero_init_ram_end);