From: Qi Zheng <zhengqi.arch@bytedance.com> To: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Subject: Re: [RFC PATCH 2/2] arm64: support HAVE_IRQ_EXIT_ON_IRQ_STACK Date: Fri, 8 Jul 2022 11:13:34 +0800 [thread overview] Message-ID: <b53dbf64-b824-89b0-dc00-b894cf9771a9@bytedance.com> (raw) In-Reply-To: <CAK8P3a1GgnmhHj+_gRYZ52=TvfBQb_xxYt1Hg-jMJ2gZqCD42w@mail.gmail.com> On 2022/7/8 04:55, Arnd Bergmann wrote: > On Thu, Jul 7, 2022 at 5:00 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote: >> On 2022/7/7 22:41, Arnd Bergmann wrote: >>> On Thu, Jul 7, 2022 at 3:38 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote: >>>> On 2022/7/7 20:49, Arnd Bergmann wrote: >>> >>> -asmlinkage void noinstr el1h_64_fiq_handler(struct pt_regs *regs) >>> +asmlinkage void noinstr el1h_64_irq_handler(struct pt_regs *regs) >>> +{ >>> + if (on_thread_stack()) >>> + call_on_irq_stack(regs, el1_irq); >> >> IMO, this can't work. Because el1_interrupt() will invoke >> arm64_preempt_schedule_irq(), which will cause scheduling on the >> IRQ stack. > > Ah, too bad. I spent some more time looking for a simpler approach, > but couldn't find one I'm happy with. One idea might be to have > callback functions for each combinations of irq/fiq with irq/pnmi > to avoid the nested callback pointers. Not sure if that helps. Maybe nested callback pointers are not always a wild beast. ;) This method does not change much, and we can also conveniently stuff all kinds of things in do_handler() that we want to run on the IRQ stack in addition to the handler(). Thanks, Qi > > Arnd -- Thanks, Qi
WARNING: multiple messages have this Message-ID (diff)
From: Qi Zheng <zhengqi.arch@bytedance.com> To: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Subject: Re: [RFC PATCH 2/2] arm64: support HAVE_IRQ_EXIT_ON_IRQ_STACK Date: Fri, 8 Jul 2022 11:13:34 +0800 [thread overview] Message-ID: <b53dbf64-b824-89b0-dc00-b894cf9771a9@bytedance.com> (raw) In-Reply-To: <CAK8P3a1GgnmhHj+_gRYZ52=TvfBQb_xxYt1Hg-jMJ2gZqCD42w@mail.gmail.com> On 2022/7/8 04:55, Arnd Bergmann wrote: > On Thu, Jul 7, 2022 at 5:00 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote: >> On 2022/7/7 22:41, Arnd Bergmann wrote: >>> On Thu, Jul 7, 2022 at 3:38 PM Qi Zheng <zhengqi.arch@bytedance.com> wrote: >>>> On 2022/7/7 20:49, Arnd Bergmann wrote: >>> >>> -asmlinkage void noinstr el1h_64_fiq_handler(struct pt_regs *regs) >>> +asmlinkage void noinstr el1h_64_irq_handler(struct pt_regs *regs) >>> +{ >>> + if (on_thread_stack()) >>> + call_on_irq_stack(regs, el1_irq); >> >> IMO, this can't work. Because el1_interrupt() will invoke >> arm64_preempt_schedule_irq(), which will cause scheduling on the >> IRQ stack. > > Ah, too bad. I spent some more time looking for a simpler approach, > but couldn't find one I'm happy with. One idea might be to have > callback functions for each combinations of irq/fiq with irq/pnmi > to avoid the nested callback pointers. Not sure if that helps. Maybe nested callback pointers are not always a wild beast. ;) This method does not change much, and we can also conveniently stuff all kinds of things in do_handler() that we want to run on the IRQ stack in addition to the handler(). Thanks, Qi > > Arnd -- Thanks, Qi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-07-08 3:13 UTC|newest] Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-07-07 11:05 [RFC PATCH 0/2] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng 2022-07-07 11:05 ` Qi Zheng 2022-07-07 11:05 ` [RFC PATCH 1/2] " Qi Zheng 2022-07-07 11:05 ` Qi Zheng 2022-07-07 12:58 ` Arnd Bergmann 2022-07-07 12:58 ` Arnd Bergmann 2022-07-07 13:43 ` Qi Zheng 2022-07-07 13:43 ` Qi Zheng 2022-07-07 13:53 ` Arnd Bergmann 2022-07-07 13:53 ` Arnd Bergmann 2022-07-07 15:05 ` Qi Zheng 2022-07-07 15:05 ` Qi Zheng 2022-07-08 2:56 ` kernel test robot 2022-07-07 11:05 ` [RFC PATCH 2/2] arm64: support HAVE_IRQ_EXIT_ON_IRQ_STACK Qi Zheng 2022-07-07 11:05 ` Qi Zheng 2022-07-07 12:49 ` Arnd Bergmann 2022-07-07 12:49 ` Arnd Bergmann 2022-07-07 13:38 ` Qi Zheng 2022-07-07 13:38 ` Qi Zheng 2022-07-07 14:41 ` Arnd Bergmann 2022-07-07 14:41 ` Arnd Bergmann 2022-07-07 15:00 ` Qi Zheng 2022-07-07 15:00 ` Qi Zheng 2022-07-07 20:55 ` Arnd Bergmann 2022-07-07 20:55 ` Arnd Bergmann 2022-07-08 3:13 ` Qi Zheng [this message] 2022-07-08 3:13 ` Qi Zheng 2022-07-08 8:52 ` Arnd Bergmann 2022-07-08 8:52 ` Arnd Bergmann 2022-07-08 9:13 ` Qi Zheng 2022-07-08 9:13 ` Qi Zheng
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