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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-12-25 07:48:10 +00:00
trezor-firmware/core/embed/boardloader/startup_stm32u5.s
2024-04-05 18:54:30 +02:00

108 lines
3.5 KiB
ArmAsm

.syntax unified
.text
.global reset_handler
.type reset_handler, STT_FUNC
reset_handler:
// set the stack protection
ldr r0, =_sstack
add r0, r0, #16 // padding
msr MSPLIM, r0
bl SystemInit
// read the first rng data and save it
ldr r0, =0 // r0 - previous value
ldr r1, =0 // r1 - whether to compare the previous value
bl rng_read
// read the next rng data and make sure it is different than previous
// r0 - value returned from previous call
ldr r1, =1 // r1 - whether to compare the previous value
bl rng_read
mov r4, r0 // save TRNG output in r4
// wipe memory to remove any possible vestiges of confidential data
fill_ram:
ldr r0, =sram1_start // r0 - point to beginning of SRAM
ldr r1, =sram1_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram2_start // r0 - point to beginning of SRAM
ldr r1, =sram2_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram3_start // r0 - point to beginning of SRAM
ldr r1, =sram3_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram4_start // r0 - point to beginning of SRAM
ldr r1, =sram4_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram5_start // r0 - point to beginning of SRAM
ldr r1, =sram5_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
ldr r0, =sram6_start // r0 - point to beginning of SRAM
ldr r1, =sram6_end // r1 - point to byte after the end of SRAM
mov r2, r4 // r2 - the word-sized value to be written
bl memset_reg
// setup environment for subsequent stage of code
clear_ram:
ldr r2, =0 // r2 - the word-sized value to be written
ldr r0, =sram1_start // r0 - point to beginning of SRAM
ldr r1, =sram1_end // r1 - point to byte after the end of SRAM
bl memset_reg
ldr r0, =sram2_start // r0 - point to beginning of SRAM
ldr r1, =sram2_end // r1 - point to byte after the end of SRAM
bl memset_reg
ldr r0, =sram3_start // r0 - point to beginning of SRAM
ldr r1, =sram3_end // r1 - point to byte after the end of SRAM
bl memset_reg
ldr r0, =sram4_start // r0 - point to beginning of SRAM
ldr r1, =sram4_end // r1 - point to byte after the end of SRAM
bl memset_reg
ldr r0, =sram5_start // r0 - point to beginning of SRAM
ldr r1, =sram5_end // r1 - point to byte after the end of SRAM
bl memset_reg
ldr r0, =sram6_start // r0 - point to beginning of SRAM
ldr r1, =sram6_end // r1 - point to byte after the end of SRAM
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
// copy confidential data in from flash
ldr r0, =confidential_vma // dst addr
ldr r1, =confidential_lma // src addr
ldr r2, =confidential_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]
// enter the application code
bl main
b shutdown_privileged
.end