* [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations @ 2016-09-09 13:44 Fabio Estevam 2016-09-09 14:40 ` Marc Zyngier 0 siblings, 1 reply; 8+ messages in thread From: Fabio Estevam @ 2016-09-09 13:44 UTC (permalink / raw) To: stable; +Cc: marc.zyngier, Fabio Estevam From: Marc Zyngier <marc.zyngier@arm.com> commit 059e232089e45b0befc9933d31209c225e08b426 upstream. On systems where a single CPU is present, the GIC may not support having SGIs delivered to a target list. In that case, we use the self-SGI mechanism to allow the interrupt to be delivered locally. Cc: <stable@vger.kernel.org> # 4.7.x Tested-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> --- Changes since v1: - Add the 4.7.x notation drivers/irqchip/irq-gic.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index c2cab57..390fac5 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -769,6 +769,13 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) int cpu; unsigned long flags, map = 0; + if (unlikely(nr_cpu_ids == 1)) { + /* Only one CPU? let's do a self-IPI... */ + writel_relaxed(2 << 24 | irq, + gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); + return; + } + raw_spin_lock_irqsave(&irq_controller_lock, flags); /* Convert our logical CPU mask into a physical one. */ -- 1.9.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 13:44 [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations Fabio Estevam @ 2016-09-09 14:40 ` Marc Zyngier 2016-09-09 15:31 ` Fabio Estevam 0 siblings, 1 reply; 8+ messages in thread From: Marc Zyngier @ 2016-09-09 14:40 UTC (permalink / raw) To: Fabio Estevam, stable; +Cc: Fabio Estevam Hi Fabio, On 09/09/16 14:44, Fabio Estevam wrote: > From: Marc Zyngier <marc.zyngier@arm.com> > > commit 059e232089e45b0befc9933d31209c225e08b426 upstream. > > On systems where a single CPU is present, the GIC may not support > having SGIs delivered to a target list. In that case, we use the > self-SGI mechanism to allow the interrupt to be delivered locally. > > Cc: <stable@vger.kernel.org> # 4.7.x > Tested-by: Fabio Estevam <fabio.estevam@nxp.com> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> I'm sorry, but what is the justification for this to be backported to a stable kernel? It is not a regression, since we never supported this kind of HW before. This is not a workaround for an erratum either. If that was a kernel bug, why not backport it all the way the the oldest stable, instead of limiting it to v4.7? Thanks, M. -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 14:40 ` Marc Zyngier @ 2016-09-09 15:31 ` Fabio Estevam 2016-09-09 15:42 ` Marc Zyngier 0 siblings, 1 reply; 8+ messages in thread From: Fabio Estevam @ 2016-09-09 15:31 UTC (permalink / raw) To: Marc Zyngier; +Cc: stable, Fabio Estevam Hi Marc, On Fri, Sep 9, 2016 at 11:40 AM, Marc Zyngier <marc.zyngier@arm.com> wrote: > Hi Fabio, > > On 09/09/16 14:44, Fabio Estevam wrote: >> From: Marc Zyngier <marc.zyngier@arm.com> >> >> commit 059e232089e45b0befc9933d31209c225e08b426 upstream. >> >> On systems where a single CPU is present, the GIC may not support >> having SGIs delivered to a target list. In that case, we use the >> self-SGI mechanism to allow the interrupt to be delivered locally. >> >> Cc: <stable@vger.kernel.org> # 4.7.x >> Tested-by: Fabio Estevam <fabio.estevam@nxp.com> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> > > I'm sorry, but what is the justification for this to be backported to a > stable kernel? It is not a regression, since we never supported this Without this patch imx6ul SoC hangs after a 'reboot' command. > kind of HW before. This is not a workaround for an erratum either. > > If that was a kernel bug, why not backport it all the way the the oldest > stable, instead of limiting it to v4.7? I can send it to 4.4 as well, if you agree. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 15:31 ` Fabio Estevam @ 2016-09-09 15:42 ` Marc Zyngier 2016-09-09 15:48 ` Fabio Estevam 0 siblings, 1 reply; 8+ messages in thread From: Marc Zyngier @ 2016-09-09 15:42 UTC (permalink / raw) To: Fabio Estevam; +Cc: stable, Fabio Estevam On 09/09/16 16:31, Fabio Estevam wrote: > Hi Marc, > > On Fri, Sep 9, 2016 at 11:40 AM, Marc Zyngier <marc.zyngier@arm.com> wrote: >> Hi Fabio, >> >> On 09/09/16 14:44, Fabio Estevam wrote: >>> From: Marc Zyngier <marc.zyngier@arm.com> >>> >>> commit 059e232089e45b0befc9933d31209c225e08b426 upstream. >>> >>> On systems where a single CPU is present, the GIC may not support >>> having SGIs delivered to a target list. In that case, we use the >>> self-SGI mechanism to allow the interrupt to be delivered locally. >>> >>> Cc: <stable@vger.kernel.org> # 4.7.x >>> Tested-by: Fabio Estevam <fabio.estevam@nxp.com> >>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >>> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> >> >> I'm sorry, but what is the justification for this to be backported to a >> stable kernel? It is not a regression, since we never supported this > > Without this patch imx6ul SoC hangs after a 'reboot' command. But that's not a regression, right? It *never* worked before, as far as I know, because we never supported such a configuration in the past. I'm a bit concerned when I see backporting random patches to random kernel versions for things that are not bugs. I'll leave it up to Greg to decide, but I thought I should point out what this patch actually is. Thanks, M. -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 15:42 ` Marc Zyngier @ 2016-09-09 15:48 ` Fabio Estevam 2016-09-09 16:06 ` Marc Zyngier 2016-09-09 16:10 ` Greg KH 0 siblings, 2 replies; 8+ messages in thread From: Fabio Estevam @ 2016-09-09 15:48 UTC (permalink / raw) To: Marc Zyngier; +Cc: stable, Fabio Estevam Hi Marc, On Fri, Sep 9, 2016 at 12:42 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: >> Without this patch imx6ul SoC hangs after a 'reboot' command. > > But that's not a regression, right? It *never* worked before, as far as > I know, because we never supported such a configuration in the past. imx6ul is supported since kernel 4.3. > I'm a bit concerned when I see backporting random patches to random > kernel versions for things that are not bugs. I'll leave it up to Greg > to decide, but I thought I should point out what this patch actually is. Not bugs? I consider the hang I get after running 'reboot' on imx6ul a bug. According to Documentation/stable_kernel_rules.txt : " - It must fix a problem that causes a build error (but not for things marked CONFIG_BROKEN), an oops, a hang, data corruption, a real security issue, or some "oh, that's not good" issue. In short, something critical. " , so that's why I submitted for stable inclusion. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 15:48 ` Fabio Estevam @ 2016-09-09 16:06 ` Marc Zyngier 2016-09-09 16:12 ` Greg KH 2016-09-09 16:10 ` Greg KH 1 sibling, 1 reply; 8+ messages in thread From: Marc Zyngier @ 2016-09-09 16:06 UTC (permalink / raw) To: Fabio Estevam; +Cc: stable, Fabio Estevam On 09/09/16 16:48, Fabio Estevam wrote: > Hi Marc, > > On Fri, Sep 9, 2016 at 12:42 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > >>> Without this patch imx6ul SoC hangs after a 'reboot' command. >> >> But that's not a regression, right? It *never* worked before, as far as >> I know, because we never supported such a configuration in the past. > > imx6ul is supported since kernel 4.3. And yet nobody reported this as an issue until the 4.8 cycle. So it doesn't look like it was annoying anyone until then. > >> I'm a bit concerned when I see backporting random patches to random >> kernel versions for things that are not bugs. I'll leave it up to Greg >> to decide, but I thought I should point out what this patch actually is. > > Not bugs? I consider the hang I get after running 'reboot' on imx6ul a bug. > > According to Documentation/stable_kernel_rules.txt : > > " - It must fix a problem that causes a build error (but not for things > marked CONFIG_BROKEN), an oops, a hang, data corruption, a real > security issue, or some "oh, that's not good" issue. In short, something > critical. " > > , so that's why I submitted for stable inclusion. > I don't, which is why I didn't tag it for stable the first place. I consider this as an unsupported configuration (MP CPU on a UP GIC), which we start supporting from 4.8 onward. Anyway, I'm not going to argue any further for such a small patch, but I've made my position clear. Thanks, M. -- Jazz is not dead. It just smells funny... ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 16:06 ` Marc Zyngier @ 2016-09-09 16:12 ` Greg KH 0 siblings, 0 replies; 8+ messages in thread From: Greg KH @ 2016-09-09 16:12 UTC (permalink / raw) To: Marc Zyngier; +Cc: Fabio Estevam, stable, Fabio Estevam On Fri, Sep 09, 2016 at 05:06:02PM +0100, Marc Zyngier wrote: > On 09/09/16 16:48, Fabio Estevam wrote: > > Hi Marc, > > > > On Fri, Sep 9, 2016 at 12:42 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > > > >>> Without this patch imx6ul SoC hangs after a 'reboot' command. > >> > >> But that's not a regression, right? It *never* worked before, as far as > >> I know, because we never supported such a configuration in the past. > > > > imx6ul is supported since kernel 4.3. > > And yet nobody reported this as an issue until the 4.8 cycle. So it > doesn't look like it was annoying anyone until then. > > > > >> I'm a bit concerned when I see backporting random patches to random > >> kernel versions for things that are not bugs. I'll leave it up to Greg > >> to decide, but I thought I should point out what this patch actually is. > > > > Not bugs? I consider the hang I get after running 'reboot' on imx6ul a bug. > > > > According to Documentation/stable_kernel_rules.txt : > > > > " - It must fix a problem that causes a build error (but not for things > > marked CONFIG_BROKEN), an oops, a hang, data corruption, a real > > security issue, or some "oh, that's not good" issue. In short, something > > critical. " > > > > , so that's why I submitted for stable inclusion. > > > > I don't, which is why I didn't tag it for stable the first place. I > consider this as an unsupported configuration (MP CPU on a UP GIC), > which we start supporting from 4.8 onward. > > Anyway, I'm not going to argue any further for such a small patch, but > I've made my position clear. As the maintainer wants this removed, I've now dropped it from the 4.7-stable queue. Fabio, just use 4.8 on this hardware and you should be fine. thanks, greg k-h ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations 2016-09-09 15:48 ` Fabio Estevam 2016-09-09 16:06 ` Marc Zyngier @ 2016-09-09 16:10 ` Greg KH 1 sibling, 0 replies; 8+ messages in thread From: Greg KH @ 2016-09-09 16:10 UTC (permalink / raw) To: Fabio Estevam; +Cc: Marc Zyngier, stable, Fabio Estevam On Fri, Sep 09, 2016 at 12:48:34PM -0300, Fabio Estevam wrote: > Hi Marc, > > On Fri, Sep 9, 2016 at 12:42 PM, Marc Zyngier <marc.zyngier@arm.com> wrote: > > >> Without this patch imx6ul SoC hangs after a 'reboot' command. > > > > But that's not a regression, right? It *never* worked before, as far as > > I know, because we never supported such a configuration in the past. > > imx6ul is supported since kernel 4.3. > > > I'm a bit concerned when I see backporting random patches to random > > kernel versions for things that are not bugs. I'll leave it up to Greg > > to decide, but I thought I should point out what this patch actually is. > > Not bugs? I consider the hang I get after running 'reboot' on imx6ul a bug. > > According to Documentation/stable_kernel_rules.txt : > > " - It must fix a problem that causes a build error (but not for things > marked CONFIG_BROKEN), an oops, a hang, data corruption, a real > security issue, or some "oh, that's not good" issue. In short, something > critical. " > > , so that's why I submitted for stable inclusion. But if it never worked to start with, that's not really a regression, that is a "make new hardware work" type thing. Did it work properly in 4.3? What caused support for this hardware to break? thanks, greg k-h ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-09-09 16:12 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-09-09 13:44 [PATCH v2] irqchip/gic: Allow self-SGIs for SMP on UP configurations Fabio Estevam 2016-09-09 14:40 ` Marc Zyngier 2016-09-09 15:31 ` Fabio Estevam 2016-09-09 15:42 ` Marc Zyngier 2016-09-09 15:48 ` Fabio Estevam 2016-09-09 16:06 ` Marc Zyngier 2016-09-09 16:12 ` Greg KH 2016-09-09 16:10 ` Greg KH
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