PMM field in mseccfg register

[atishp04]

The section 3.1.19. Machine Security Configuration (mseccfg) Register says

"The definition of the PMM field will be furnished by the forthcoming Smmpm extension. Its allocation within mseccfg may change prior to the ratification of that extension."

Is this old text referring to pointer masking extension or something else ? There are no other reference to Smmpm.

[pdonahue-ventana]

https://github.com/riscv/riscv-j-extension/blob/e108fc489cf4f9c5be48e509ce0f96879e782afa/zjpm/instructions.adoc?plain=1#L53