Yes , there is hardware involved . See the thing is the hardware solution (support) here (or anywhere) means that the underlying hardware is providing some instructions / registers / pins / techniques to implement the solution. Lets for example the Test and Set Lock or the test-and-set instruction is an instruction used to write 1 (set) to a memory location and return its old value as a single atomic (i.e., non-interruptible) operation.
Now your question where is the hardware involved?
It's involved right here single atomic (i.e., non-interruptible) operation this thing is ensured by hardware . For a vague picture what's happening down there , it is the system that is providing us a TSL instruction with such property . You cannot just implement the solution in just any hardware . Unlike software solution which does not depend on instruction set or underlying hardware.
Hopes that's clear your doubt