Question about NRF5340 SRAM execution permission

RE: Question about NRF5340 SRAM execution permission

Amanda Hsieh — Tue, 16 Nov 2021 08:42:37 GMT

Hi,

There is no standard method to enable EXEC on the whole SRAM because this is considered really really bad from a security perspective. What you could do is to define a new contained region in the SRAM and add that region to the mpu_config structure with the proper attributes as done for example in soc/arm/st_stm32/stm32h7/mpu_regions.c (see the SRAM3_ETH_BUF region)

-Amanda

RE: Question about NRF5340 SRAM execution permission

David Duan — Mon, 15 Nov 2021 08:56:27 GMT

Hi Amanda

Thanks for your suggestion

we found that the RAM excution access is disabled on default setting.

currently we use below two method to enable excution access.(NCS1.5.0)

1. Remove "NOT_EXEC" on line 123 (zephyr\include\arch\arm\aarch32\cortex_m\mpu\arm_mpu_v8m.h)

2. use arm_core_mpu_disable

my question is do we have some standard method to enable the access ?

for example some marco ?

RE: Question about NRF5340 SRAM execution permission

Amanda Hsieh — Fri, 12 Nov 2021 13:47:41 GMT

Hi,

Besides this is a really bad idea the customer probably wants to look at soc/arm/common/cortex_m/arm_mpu_regions.c and in particular to the REGION_RAM_ATTR macro

Regards,
Amanda