meta-morello-distro

This layer provides user space libraries machine translated to Morello and recompiled with purecap (c64) for the ARM Morello SDK.

It allows to run purecap and non purecap versions of the libraries to be tested in parallel. Purecap libraries have a dedicated sysroot.

Building images

$ kas build ./meta-morello-distro/kas/debug-soc.yml

Limitations

The purecap libraries are tested to a limited degree.

Yocto-wise:

• package Q&A is disabled and runtime dependency checks
• ptest is disabled/ignored
• recipes and package config can be incomplete/broken

Structure

Most of the recipes here are copies of existing recipes in other layers postfixed with morello, source of the original recipe is listed in the MORELLO_SRC variable, the original recipe path is preserved, ${PV} is not. The git hashes of layers that were used as base of these recipes are stored in MORELLO_LAYER_SRC_REF variable in the layer.conf file.

The reason for this is that the c64 versions of the libraries live in parallel to the a64 on the system, which is a design choice, hence a simple *.bbappend would not cut it.

The purecap libraries are placed in the purecap sysroot, as defined by ${PURECAP_SYSROOT_DIR} in meta-morello [1], which is where the runtime linker shall look for all dependencies.

Most of the CHERI patches are placed in the...cheri-patches folder at the root of the said recipe.

Some sources are pulled from CHERI-BSD repo and then patched further to work on Linux. In some cases patches are taken from CHERI-BSD and rebased on top of different versions of the said libraries. There are cases where we were patching a library oblivious to the fact that a CHERI port already exists. Some contributions were not found elsewhere.

If you see any errors or are the author of these patches/recipes and think we have missed something (patch authors etc.) please reach out to us and it shall be fixed !

The current userland libraries consist of:

• postgresql 9.6
• zabbix 5.0.38 server/agent/proxy (with embedded JS)
• curl/openssl/zlib/ncurses/readline/ et al.

Adding new recipes:

• in theory the dev process should be as simple as:

  • find existing recipe for the library you want
  • copy over its content into library-morello_X.Y.Z.bb
  • add:

  inherit pure-cap-kheaders purecap-sysroot
  ...
  TOOLCHAIN = "${MORELLO_TOOLCHAIN}"
  

  • compile
  • digest the logs
  • create patches and put them in the cheri-patches folder
  • repeat the last two steps until there are no errors
  • add to the image
  • watch it crash at runtime (FVP is reducing the length of the dev loop here)
  • run through gdb
  • create more cheri-patches

• if the are no obvious runtime errors you are done

We tend to stick inherit/requires at the top of the *.bb files for readability, do the same where possible.

Contributing

We accept patches through the mailing list only, the patch should be named [meta-morello-distro] https://op-lists.linaro.org/mailman3/lists/linux-morello-distros.op-lists.linaro.org/

References

[1] https://git.morello-project.org/morello/meta-morello

maintainers

• Pawel Zalewski pzalewski@thegoodpenguin.co.uk
• Harrison Carter hcarter@thegoodpenguin.co.uk