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trezor-firmware/core/embed/bootloader/startup.s
Ondrej Mikle b69ef9d168 feat(core): Copy firmware image header to bootloader RAM to be able to skip directly to firmware install, jumping from firmware to bootloader
Change linking of util.s and limited version of util.s to avoid mistakes
with boardloader etc.
2023-09-11 14:36:11 +02:00

42 lines
1.3 KiB
ArmAsm

.syntax unified
.text
.global reset_handler
.type reset_handler, STT_FUNC
reset_handler:
// setup environment for subsequent stage of code
ldr r0, =ccmram_start // r0 - point to beginning of CCMRAM
ldr r1, =firmware_header_start // r1 - point to byte where firmware image header might start
ldr r2, =0 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram_start // r0 - point to beginning of SRAM
ldr r1, =sram_end // r1 - point to byte after the end of SRAM
ldr r2, =0 // r2 - the word-sized value to be written
bl memset_reg
// copy data in from flash
ldr r0, =data_vma // dst addr
ldr r1, =data_lma // src addr
ldr r2, =data_size // size in bytes
bl memcpy
// setup the stack protector (see build script "-fstack-protector-all") with an unpredictable value
bl rng_get
ldr r1, = __stack_chk_guard
str r0, [r1]
// re-enable exceptions
// according to "ARM Cortex-M Programming Guide to Memory Barrier Instructions" Application Note 321, section 4.7:
// "If it is not necessary to ensure that a pended interrupt is recognized immediately before
// subsequent operations, it is not necessary to insert a memory barrier instruction."
cpsie f
// enter the application code
bl main
b shutdown_privileged
.end