aarch64: Restrict address mappings in loader.rs#464
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Limit the 1:1 address mapping in the loader to cover only the necessary blocks using level-2 translation tables and with 2MB blocks. Don't map device memory at all, therefore, printf must not be used in the elfloader after the MMU is enabled. This prevents speculative accesses to device or secure memory which otherwise would cause faults or unwanted side-effects. Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
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Hello,
This is a rework of the existing support committed in elfloader:
seL4/seL4_tools#244
and discussed here:
https://lists.sel4.systems/hyperkitty/list/devel@sel4.systems/thread/DJNDO5CUQBKGIA4SQHXCNQ3T6SKZEY4A/
This patch limits the 1:1 address mapping in the loader to cover only the necessary blocks using level-2 translation tables with 2MB blocks. The UART MMIO address is now exposed as a global uart_addr variable.
This prevents speculative accesses to device or secure memory, which could otherwise cause faults or unwanted side effects.
This has been tested only on STM32MP2. Testers on other platforms would be greatly appreciated.
Thank you for your review.