Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
Once we start instrumenting globals, all addresses including those of string literals
that we pass to the operating system will start being tagged. Since we can't rely
on the operating system to be able to cope with these addresses, we need to untag
them before passing them to the operating system. This change introduces a macro
that does so and uses it everywhere it is needed.
Differential Revision: https://reviews.llvm.org/D65768
llvm-svn: 367938
