- Add per app flash storage
- Adds four data areas. An app can allocate an area. Once allocated
the area is tied to the CDI of the app and can only be
read/written/deallocated by the same app.
- Add two pre loaded app slots to flash
- Load an app from the first slot at boot. The app digest must match a
specific digest specified in firmware.
- Optionally load an app from the second slot
- Add a resetinfo area in FW_RAM which is used to signal an app's intent
of resetting the system and, optionally, pass data to firmware or the
next app in a bootchain.
Co-authored-by: Jonas Thörnblad <jonas@tillitis.se>
Co-authored-by: Mikael Ågren <mikael@tillitis.se>
Co-authored-by: Daniel Jobson <jobson@tillitis.se>
In order to be able to leave data for firmware signalling the
intention with a reset or to leave data for the next app in a chain of
apps, we introduce a part of FW_RAM that can be used to store this
data. In order to do this, we:
- Change size of ROM from 6 KB to 8 KB.
- Change size of FW_RAM, from 2 KB to 4 KB.
- Add RESETINFO memory partition inside FW_RAM.
- Add generation of map file.
- Change CFLAGS from using -O2 to using -Os.
- Update address ranges for valid access to ROM and FW_RAM.
- Move stack to be located before data+bss and the RESETINFO data
above them. This also means we introduce hardware stack overflow
protection through the Security Monitor.
- Revise firmware README to the new use of FW_RAM.
We don't use any .data or .bss segment at all to keep all the firmware
variables in the stack in protected fw_ram.
Signed-off-by: Daniel Lublin <daniel@lublin.se>
