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Although a wide range of potential applications exists for the ARMV8-M processors, developers working on secure real-time applications will certainly see the largest benefit. So far, the ARMV8-M architecture can be found in M23 and M33 Cortex-M and M35P processors. Let’s take a look at the new features included in ARMV8-M and how these processors differ from previous generation ARMV7-M parts.
[...] The ARMV8-M feature that really sets the M23, M33, and M35P apart is their support for ARM TrustZone. TrustZone is a security extension that provides hardware isolation within the microcontroller so that developers can create secure and unsecure regions. These regions can be locations in RAM, Flash, or even interrupts and peripherals. The separation between secure and unsecure regions creates isolation within the microcontroller, allowing developers to protect mission-critical code and data.
The isolation creates two new modes that the processor can be running in: secure and unsecure. When in secure mode, the executing code can access all memory within both the secure and unsecure zones. However, if the processor is executing in the unsecure zone, only the unsecure regions can be seen. The secure regions are hidden and cannot be executed from the unsecure state without special code being added, which creates a gateway to access a secure call. This makes it possible to use secure functions while hiding what is happening behind the scenes.
There are several other new features that developers will find interesting besides the TrustZone extension. These include:
- Simpler MPU setup
- Flexible breakpoint configuration
- Improved trace support
- Instruction set enhancements
- Dynamic reprioritization of interrupts
(Score: 2) by sjames on Saturday August 11 2018, @03:18PM
Trust Zone is more akin to Intel's SMM. Since it has no ability to enforce booting with a signed firmware image is limited due to lack of a secondary processor with inaccessible firmware, It can help to keep a secret, but it can't keep a skilled end user from kicking it out of the system (secrets and all) and running firmware of the owner's choosing.
As has been pointed out, the M stands for microcontroller, these aren't the ARMs that Linux runs on. If you want an easy introduction to M profile ARM, there are a number of Arduino compatible boards with an ARM SOC.