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https://github.com/trezor/trezor-firmware.git
synced 2024-11-19 05:58:09 +00:00
57 lines
1.8 KiB
ArmAsm
57 lines
1.8 KiB
ArmAsm
.syntax unified
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.text
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.global reset_handler
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.type reset_handler, STT_FUNC
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reset_handler:
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bl SystemInit
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// read the first rng data and save it
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ldr r0, =0 // r0 - previous value
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ldr r1, =0 // r1 - whether to compare the previous value
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bl rng_read
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// read the next rng data and make sure it is different than previous
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// r0 - value returned from previous call
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ldr r1, =1 // r1 - whether to compare the previous value
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bl rng_read
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mov r4, r0 // save TRNG output in r4
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// wipe memory to remove any possible vestiges of sensitive data
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// use unpredictable value as a defense against side-channels
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ldr r0, =ccmram_start // r0 - point to beginning of CCMRAM
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ldr r1, =ccmram_end // r1 - point to byte after the end of CCMRAM
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mov r2, r4 // r2 - the word-sized value to be written
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bl memset_reg
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ldr r0, =sram_start // r0 - point to beginning of SRAM
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ldr r1, =sram_end // r1 - point to byte after the end of SRAM
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mov r2, r4 // r2 - the word-sized value to be written
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bl memset_reg
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// setup environment for subsequent stage of code
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ldr r0, =ccmram_start // r0 - point to beginning of CCMRAM
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ldr r1, =ccmram_end // r1 - point to byte after the end of CCMRAM
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ldr r2, =0 // r2 - the word-sized value to be written
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bl memset_reg
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ldr r0, =sram_start // r0 - point to beginning of SRAM
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ldr r1, =sram_end // r1 - point to byte after the end of SRAM
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ldr r2, =0 // r2 - the word-sized value to be written
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bl memset_reg
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// copy data in from flash
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ldr r0, =data_vma // dst addr
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ldr r1, =data_lma // src addr
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ldr r2, =data_size // size in bytes
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bl memcpy
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// enter the application code
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bl main
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// loop forever if the application code returns
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b .
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.end
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