On Wed, May 05, 2021 at 11:34:51PM -0500, Christopher M. Riedl wrote: > Powerpc allows for multiple CPUs to patch concurrently. When patching > with STRICT_KERNEL_RWX a single patching_mm is allocated for use by all > CPUs for the few times that patching occurs. Use a spinlock to protect > the patching_mm from concurrent use. > > Modify patch_instruction() to acquire the lock, perform the patch op, > and then release the lock. > > Also introduce {lock,unlock}_patching() along with > patch_instruction_unlocked() to avoid per-iteration lock overhead when > patch_instruction() is called in a loop. A follow-up patch converts some > uses of patch_instruction() to use patch_instruction_unlocked() instead.
x86 uses text_mutex for all this, why not do the same?