Messages in this thread | | | Date | Wed, 10 Feb 2021 11:57:40 +1000 | From | Nicholas Piggin <> | Subject | Re: [PATCH v5 18/22] powerpc/syscall: Remove FULL_REGS verification in system_call_exception |
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Excerpts from Christophe Leroy's message of February 10, 2021 12:31 am: > > > Le 09/02/2021 à 03:02, Nicholas Piggin a écrit : >> Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am: >>> For book3s/64, FULL_REGS() is 'true' at all time, so the test voids. >>> For others, non volatile registers are saved inconditionally. >>> >>> So the verification is pointless. >>> >>> Should one fail to do it, it would anyway be caught by the >>> CHECK_FULL_REGS() in copy_thread() as we have removed the >>> special versions ppc_fork() and friends. >>> >>> null_syscall benchmark reduction 4 cycles (332 => 328 cycles) >> >> I wonder if we rather make a CONFIG option for a bunch of these simpler >> debug checks here (and also in interrupt exit, wrappers, etc) rather >> than remove them entirely. > > We can drop this patch if you prefer. Anyway, like book3s/64, once ppc32 also do interrupt > entry/exit in C, FULL_REGS() will already return true.
Sure let's do that.
Thanks, Nick
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