Re: [PATCH 3/6] irqchip: RISC-V Local Interrupt Controller Driver
From: Christoph Hellwig <hch@lst.de>
Date: 2018-07-25 11:21:24
Also in:
linux-riscv, lkml
From: Christoph Hellwig <hch@lst.de>
Date: 2018-07-25 11:21:24
Also in:
linux-riscv, lkml
On Wed, Jul 25, 2018 at 12:18:39PM +0100, Marc Zyngier wrote:
This feels odd. It means that you cannot have the following sequence: local_irq_disable(); enable_irq(x); // where x is owned by a remote hart as smp_call_function_single() requires interrupts to be enabled. More fundamentally, why are you trying to make these interrupts look global while they aren't? arm/arm64 have similar restrictions with GICv2 and earlier, and treats these interrupts as per-cpu. Given that the drivers that deal with drivers connected to the per-hart irqchip are themselves likely to be aware of the per-cpu aspect, it would make sense to align things (we've been through that same discussion about the clocksource driver a few weeks back).
Right now the only direct consumers are said clocksource, the PLIC driver later in this series and the RISC-V arch IPI code. None of them is going to do a manual enable_irq, so I guess the remote case of the code is simply dead code. I'll take a look at converting them to per-cpu. I guess the GICv2 driver is the best template?