/** Simplified memory map for the bootloader. * Make sure the bootloader can load into main memory without overwriting itself. * * ESP32-C3 ROM static data usage is as follows: * - 0x3fccae00 - 0x3fcdc710: Shared buffers, used in UART/USB/SPI download mode only * - 0x3fcdc710 - 0x3fcde710: PRO CPU stack, can be reclaimed as heap after RTOS startup * - 0x3fcde710 - 0x3fce0000: ROM .bss and .data (not easily reclaimable) * * The 2nd stage bootloader can take space up to the end of ROM shared * buffers area (0x3fcdc710). */ /* The offset between Dbus and Ibus. Used to convert between 0x403xxxxx and 0x3fcxxxxx addresses. */ iram_dram_offset = 0x700000; /* We consider 0x3fcdc710 to be the last usable address for 2nd stage bootloader stack overhead, dram_seg, * and work out iram_seg and iram_loader_seg addresses from there, backwards. */ /* These lengths can be adjusted, if necessary: */ bootloader_usable_dram_end = 0x3fcdc710; bootloader_stack_overhead = 0x2000; /* For safety margin between bootloader data section and startup stacks */ bootloader_dram_seg_len = 0x5000; bootloader_iram_loader_seg_len = 0x7000; bootloader_iram_seg_len = 0x2000; /* Start of the lower region is determined by region size and the end of the higher region */ bootloader_dram_seg_end = bootloader_usable_dram_end - bootloader_stack_overhead; bootloader_dram_seg_start = bootloader_dram_seg_end - bootloader_dram_seg_len; bootloader_iram_loader_seg_start = bootloader_dram_seg_start - bootloader_iram_loader_seg_len + iram_dram_offset; bootloader_iram_seg_start = bootloader_iram_loader_seg_start - bootloader_iram_seg_len; MEMORY { iram_seg (RWX) : org = bootloader_iram_seg_start, len = bootloader_iram_seg_len iram_loader_seg (RWX) : org = bootloader_iram_loader_seg_start, len = bootloader_iram_loader_seg_len dram_seg (RW) : org = bootloader_dram_seg_start, len = bootloader_dram_seg_len } /* Default entry point: */ ENTRY(call_start_cpu0); SECTIONS { .iram_loader.text : { . = ALIGN (16); _loader_text_start = ABSOLUTE(.); *(.stub .gnu.warning .gnu.linkonce.literal.* .gnu.linkonce.t.*.literal .gnu.linkonce.t.*) *(.iram1 .iram1.*) /* catch stray IRAM_ATTR */ *liblog.a:(.literal .text .literal.* .text.*) *libgcc.a:(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_clock_loader.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_common_loader.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_flash.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_random.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_random*.*(.literal.bootloader_random_disable .text.bootloader_random_disable) *libbootloader_support.a:bootloader_random*.*(.literal.bootloader_random_enable .text.bootloader_random_enable) *libbootloader_support.a:bootloader_efuse_esp32c3.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_utility.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_sha.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_console_loader.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_panic.*(.literal .text .literal.* .text.*) *libbootloader_support.a:bootloader_soc.*(.literal .text .literal.* .text.*) *libbootloader_support.a:esp_image_format.*(.literal .text .literal.* .text.*) *libbootloader_support.a:flash_encrypt.*(.literal .text .literal.* .text.*) *libbootloader_support.a:flash_encryption_secure_features.*(.literal .text .literal.* .text.*) *libbootloader_support.a:flash_partitions.*(.literal .text .literal.* .text.*) *libbootloader_support.a:secure_boot.*(.literal .text .literal.* .text.*) *libbootloader_support.a:secure_boot_secure_features.*(.literal .text .literal.* .text.*) *libbootloader_support.a:secure_boot_signatures_bootloader.*(.literal .text .literal.* .text.*) *libmicro-ecc.a:*.*(.literal .text .literal.* .text.*) *libspi_flash.a:*.*(.literal .text .literal.* .text.*) *libhal.a:wdt_hal_iram.*(.literal .text .literal.* .text.*) *libesp_hw_support.a:rtc_clk.*(.literal .text .literal.* .text.*) *libesp_hw_support.a:rtc_time.*(.literal .text .literal.* .text.*) *libesp_hw_support.a:regi2c_ctrl.*(.literal .text .literal.* .text.*) *libefuse.a:*.*(.literal .text .literal.* .text.*) *(.fini.literal) *(.fini) *(.gnu.version) _loader_text_end = ABSOLUTE(.); } > iram_loader_seg .iram.text : { . = ALIGN (16); *(.entry.text) *(.init.literal) *(.init) } > iram_seg /* Shared RAM */ .dram0.bss (NOLOAD) : { . = ALIGN (8); _dram_start = ABSOLUTE(.); _bss_start = ABSOLUTE(.); *(.dynsbss) *(.sbss) *(.sbss.*) *(.gnu.linkonce.sb.*) *(.scommon) *(.sbss2) *(.sbss2.*) *(.gnu.linkonce.sb2.*) *(.dynbss) *(.bss) *(.bss.*) *(.gnu.linkonce.b.*) *(COMMON) . = ALIGN (8); _bss_end = ABSOLUTE(.); } > dram_seg .dram0.data : { _data_start = ABSOLUTE(.); *(.data) *(.data.*) *(.gnu.linkonce.d.*) *(.data1) *(.sdata) *(.sdata.*) *(.gnu.linkonce.s.*) *(.gnu.linkonce.s2.*) *(.jcr) _data_end = ABSOLUTE(.); } > dram_seg .dram0.rodata : { _rodata_start = ABSOLUTE(.); *(.rodata) *(.rodata.*) *(.gnu.linkonce.r.*) *(.rodata1) *(.sdata2 .sdata2.* .srodata .srodata.*) __XT_EXCEPTION_TABLE_ = ABSOLUTE(.); *(.xt_except_table) *(.gcc_except_table) *(.gnu.linkonce.e.*) *(.gnu.version_r) *(.eh_frame) . = (. + 3) & ~ 3; /* C++ constructor and destructor tables, properly ordered: */ __init_array_start = ABSOLUTE(.); KEEP (*crtbegin.*(.ctors)) KEEP (*(EXCLUDE_FILE (*crtend.*) .ctors)) KEEP (*(SORT(.ctors.*))) KEEP (*(.ctors)) __init_array_end = ABSOLUTE(.); KEEP (*crtbegin.*(.dtors)) KEEP (*(EXCLUDE_FILE (*crtend.*) .dtors)) KEEP (*(SORT(.dtors.*))) KEEP (*(.dtors)) /* C++ exception handlers table: */ __XT_EXCEPTION_DESCS_ = ABSOLUTE(.); *(.xt_except_desc) *(.gnu.linkonce.h.*) __XT_EXCEPTION_DESCS_END__ = ABSOLUTE(.); *(.xt_except_desc_end) *(.dynamic) *(.gnu.version_d) _rodata_end = ABSOLUTE(.); /* Literals are also RO data. */ _lit4_start = ABSOLUTE(.); *(*.lit4) *(.lit4.*) *(.gnu.linkonce.lit4.*) _lit4_end = ABSOLUTE(.); . = ALIGN(4); _dram_end = ABSOLUTE(.); } > dram_seg .iram.text : { _stext = .; _text_start = ABSOLUTE(.); *(.literal .text .literal.* .text.* .stub .gnu.warning .gnu.linkonce.literal.* .gnu.linkonce.t.*.literal .gnu.linkonce.t.*) *(.iram .iram.*) /* catch stray IRAM_ATTR */ *(.fini.literal) *(.fini) *(.gnu.version) /** CPU will try to prefetch up to 16 bytes of * of instructions. This means that any configuration (e.g. MMU, PMS) must allow * safe access to up to 16 bytes after the last real instruction, add * dummy bytes to ensure this */ . += 16; _text_end = ABSOLUTE(.); _etext = .; } > iram_seg } /** * Appendix: Memory Usage of ROM bootloader * * 0x3fccae00 ------------------> _dram0_0_start * | | * | | * | | 1. Large buffers that are only used in certain boot modes, see shared_buffers.h * | | * | | * 0x3fcdc710 ------------------> __stack_sentry * | | * | | 2. Startup pro cpu stack (freed when IDF app is running) * | | * 0x3fcde710 ------------------> __stack (pro cpu) * | | * | | * | | 3. Shared memory only used in startup code or nonos/early boot* * | | (can be freed when IDF runs) * | | * | | * 0x3fcdf060 ------------------> _dram0_rtos_reserved_start * | | * | | * | | 4. Shared memory used in startup code and when IDF runs * | | * | | * 0x3fcdf664 ------------------> _dram0_rtos_reserved_end * | | * 0x3fcdf830 ------------------> _data_start_interface * | | * | | 5. End of DRAM is the 'interface' data with constant addresses (ECO compatible) * | | * 0x3fce0000 ------------------> _data_end_interface */