Hi Marc, On 05/05/16 13:06, Marc Zyngier wrote: > Hi Jon, > > On 04/05/16 17:25, Jon Hunter wrote: >> Setting the interrupt type for private peripheral interrupts (PPIs) may >> not be supported by a given GIC because it is IMPLEMENTATION DEFINED >> whether this is allowed. There is no way to know if setting the type is >> supported for a given GIC and so the value written is read back to >> verify it matches the desired configuration. If it does not match then >> an error is return. >> >> There are cases where the interrupt configuration read from firmware >> (such as a device-tree blob), has been incorrect and hence >> gic_configure_irq() has returned an error. This error has gone >> undetected because the error code returned was ignored but the interrupt >> still worked fine because the configuration for the interrupt could not >> be overwritten. >> >> Given that this has done undetected and that failing to set the >> configuration for a PPI may not be a catastrophic, don't return an error >> but WARN if we fail to configure a PPI. This will allows us to fix up >> any places in the kernel where we should be checking the return status >> and maintain backward compatibility with firmware images that may have >> incorrect PPI configurations. >> >> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> >> Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> >> --- >> drivers/irqchip/irq-gic-common.c | 11 +++++++---- >> 1 file changed, 7 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c >> index ffff5a45f1e3..9fa92a17225c 100644 >> --- a/drivers/irqchip/irq-gic-common.c >> +++ b/drivers/irqchip/irq-gic-common.c >> @@ -56,12 +56,15 @@ int gic_configure_irq(unsigned int irq, unsigned int type, >> >> /* >> * Write back the new configuration, and possibly re-enable >> - * the interrupt. If we fail to write a new configuration, >> - * return an error. >> + * the interrupt. WARN if we fail to write a new configuration >> + * and return an error if we failed to write the configuration >> + * for an SPI. If we fail to write the configuration for a PPI >> + * this is most likely because the GIC does not allow us to set >> + * the configuration and so it is not a catastrophic failure. >> */ >> writel_relaxed(val, base + GIC_DIST_CONFIG + confoff); >> - if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val) >> - ret = -EINVAL; >> + if (WARN_ON(readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val)) >> + ret = irq < 32 ? 0 : -EINVAL; >> >> if (sync_access) >> sync_access(); >> > > I'm going to slightly backpedal on that one: > > When running in non-secure mode, you can reconfigure secure interrupts Do you mean 'cannot'? > (for obvious reasons). But you don't know which mode you're running in > either. A typical example is the arch timer, which requests both secure > and non-secure interrupts, because we cannot know which side of the CPU > we're running on. In the non-secure case, we end-up with a splat that > is rather undeserved. Yes seems sensible. > So I'm tempted to tone down the splat in the PPI case like this: > > diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c > index 083c303..1605e42 100644 > --- a/drivers/irqchip/irq-gic-common.c > +++ b/drivers/irqchip/irq-gic-common.c > @@ -63,8 +63,17 @@ int gic_configure_irq(unsigned int irq, unsigned int type, > * the configuration and so it is not a catastrophic failure. > */ > writel_relaxed(val, base + GIC_DIST_CONFIG + confoff); > - if (WARN_ON(readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val)) > - ret = irq < 32 ? 0 : -EINVAL; > + oldval = readl_relaxed(base + GIC_DIST_CONFIG + confoff); > + if (oldval != val) { > + if (irq < 32) { > + pr_warn("GIC: PPI%d is either secure or misconfigured\n", > + irq - 16); > + ret = 0; > + } else { > + WARN_ON(1); > + ret = -EINVAL; > + } > + } > > if (sync_access) > sync_access(); > > Thoughts? That is fine with me. Do you want me to re-spin or do you want to apply your change on top? However, before I re-spin would like to get your thoughts on patches 13-17. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html