Re: [PATCH 3/4] powerpc/64: system call remove non-volatile GPR save optimisation

On Tue, Aug 27, 2019 at 01:30:09PM +1000, Nicholas Piggin wrote: > -435 nospu clone3 ppc_clone3 > +435 32 clone3 ppc_clone3 > sys_clone3 > +435 64 clone3 sys_clone3 > +435 nospu clone3

[PATCH 3/4] powerpc/64: system call remove non-volatile GPR save optimisation

powerpc has an optimisation where interrupts avoid saving the non-volatile (or callee saved) registers to the interrupt stack frame if they are not required. Two problems with this are that an interrupt does not always know whether it will need non-volatiles; and if it does need them, they can onl