From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@infradead.org (Christoph Hellwig) Date: Tue, 14 Aug 2018 06:35:36 -0700 Subject: [PATCH v3 1/2] RISC-V: Define sys_riscv_flush_icache when SMP=n In-Reply-To: References: <20180810083804.GA20415@infradead.org> Message-ID: <20180814133536.GB28080@infradead.org> To: linux-riscv@lists.infradead.org List-Id: linux-riscv.lists.infradead.org On Fri, Aug 10, 2018 at 11:27:37AM -0700, Palmer Dabbelt wrote: > I'm not sure. We can implement the syscall fine in !SMP, it's just that the > vDSO is expected to always eat these calls because in non-SMP mode you can > do a global fence.i by just doing a local fence.i (there's only one hart). > > The original rationale behind not having the syscall in non-SMP mode was to > limit the user ABI, but on looking again that seems like it's just a bit of > extra complexity that doesn't help anything. It's already been demonstrated > that nothing is checking the error because it's been silently slipping past > userspace for six months, so the extra complexity seems like it'll just > cause someone else to have to chase the bug in the future. > > But I'm really OK either way. Is there a precedent for what to do here? I don't know of any.