Re: [PATCH 1/2] powerpc/64s: Fix entry flush patching w/strict RWX & hash

On Fri, 14 May 2021 00:07:59 +1000, Michael Ellerman wrote:

The entry flush mitigation can be enabled/disabled at runtime. When this
happens it results in the kernel patching its own instructions to
enable/disable the mitigation sequence.

With strict kernel RWX enabled instruction patching happens via a
secondary mapping of the kernel text, so that we don't have to make the
primary mapping writable. With the hash MMU this leads to a hash fault,
which causes us to execute the exception entry which contains the entry
flush mitigation.

[...]

Applied to powerpc/fixes.

[1/2] powerpc/64s: Fix entry flush patching w/strict RWX & hash
      https://git.kernel.org/powerpc/c/49b39ec248af863781a13aa6d81c5f69a2928094
[2/2] powerpc/64s: Fix stf mitigation patching w/strict RWX & hash
      https://git.kernel.org/powerpc/c/5b48ba2fbd77bc68feebd336ffad5ff166782bde

cheers