Only map with executable permissions when using code space

mmtk / mmtk-core

Memory Management ToolKit

https://www.mmtk.io

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Only map with executable permissions when using code space #1176

Closed k-sareen closed 3 months ago

k-sareen commented 4 months ago

This PR closes https://github.com/mmtk/mmtk-core/issues/7. This PR

refactors MmapStrategy to include protection flags, and allows each space to pass Mmapstrategy to the mmapper.
removes exec permission from most spaces. Only code spaces will have exec permission.
adds a feature exec_permission_on_all_spaces for bindings that may allocate code into normal spaces.

qinsoon commented 4 months ago

I pushed some changes. It refactors MmapStrategy and allows spaces to pass what protection flags they need for mmap. With the change, only code spaces are mmapped with exec.

k-sareen commented 4 months ago

Thank you for the refactoring. It looks much better now. Jikes is broken for some reason. Does it depend on exec permissions on non-codespaces perhaps...?

qinsoon commented 4 months ago

Thank you for the refactoring. It looks much better now. Jikes is broken for some reason. Does it depend on exec permissions on non-codespaces perhaps...?

I am not sure. MMTK in JikesRVM does mmap all the spaces with exec. Our Julia binding currently allocates code into normal spaces.

I added a feature exec_permission_on_all_spaces which allows exec for all the spaces. I can try turn on the feature for those two bindings.

qinsoon commented 4 months ago

binding-refs JIKESRVM_BINDING_REPO=qinsoon/mmtk-jikesrvm JIKESRVM_BINDING_REF=update-mmtk-core-pr-1176 V8_BINDING_REPO=qinsoon/mmtk-v8 V8_BINDING_REF=update-mmtk-core-pr-1176

qinsoon commented 4 months ago

It seems Julia does not need exec permission for normal spaces, but V8 (NoGC has no code space) and JikesRVM need.