From 9b256714979fad61ae11d90b53cf67dd5e6484eb Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 7 Feb 2017 11:35:31 +1100 Subject: powerpc/powernv: Fix CPU hotplug to handle waking on HVI The IPIs come in as HVI not EE, so we need to test the appropriate SRR1 bits. The encoding is such that it won't have false positives on P7 and P8 so we can just test it like that. We also need to handle the icp-opal variant of the flush. Fixes: d74361881f0d ("powerpc/xics: Add ICP OPAL backend") Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/sysdev/xics/icp-opal.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c index 60c57657c772..c96c0cb95d87 100644 --- a/arch/powerpc/sysdev/xics/icp-opal.c +++ b/arch/powerpc/sysdev/xics/icp-opal.c @@ -132,6 +132,35 @@ static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id) return smp_ipi_demux(); } +/* + * Called when an interrupt is received on an off-line CPU to + * clear the interrupt, so that the CPU can go back to nap mode. + */ +void icp_opal_flush_interrupt(void) +{ + unsigned int xirr; + unsigned int vec; + + do { + xirr = icp_opal_get_xirr(); + vec = xirr & 0x00ffffff; + if (vec == XICS_IRQ_SPURIOUS) + break; + if (vec == XICS_IPI) { + /* Clear pending IPI */ + int cpu = smp_processor_id(); + kvmppc_set_host_ipi(cpu, 0); + opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff); + } else { + pr_err("XICS: hw interrupt 0x%x to offline cpu, " + "disabling\n", vec); + xics_mask_unknown_vec(vec); + } + + /* EOI the interrupt */ + } while (opal_int_eoi(xirr) > 0); +} + #endif /* CONFIG_SMP */ static const struct icp_ops icp_opal_ops = { -- cgit v1.2.3 From f83e6862047e1e371bdc5d512dd6cabe8a3965b8 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 7 Feb 2017 11:35:36 +1100 Subject: powerpc/powernv: Properly set "host-ipi" on IPIs Otherwise KVM will fail to pass them through to the host Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/sysdev/xics/icp-opal.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c index c96c0cb95d87..f9670eabfcfa 100644 --- a/arch/powerpc/sysdev/xics/icp-opal.c +++ b/arch/powerpc/sysdev/xics/icp-opal.c @@ -120,14 +120,16 @@ static void icp_opal_cause_ipi(int cpu, unsigned long data) { int hw_cpu = get_hard_smp_processor_id(cpu); + kvmppc_set_host_ipi(cpu, 1); opal_int_set_mfrr(hw_cpu, IPI_PRIORITY); } static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id) { - int hw_cpu = hard_smp_processor_id(); + int cpu = smp_processor_id(); - opal_int_set_mfrr(hw_cpu, 0xff); + kvmppc_set_host_ipi(cpu, 0); + opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff); return smp_ipi_demux(); } -- cgit v1.2.3 From a69e2fb70350a66f91175cd2625f1e8215c5b6e9 Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Fri, 3 Mar 2017 11:58:44 +1100 Subject: powerpc/xics: Work around limitations of OPAL XICS priority handling The CPPR (Current Processor Priority Register) of a XICS interrupt presentation controller contains a value N, such that only interrupts with a priority "more favoured" than N will be received by the CPU, where "more favoured" means "less than". So if the CPPR has the value 5 then only interrupts with a priority of 0-4 inclusive will be received. In theory the CPPR can support a value of 0 to 255 inclusive. In practice Linux only uses values of 0, 4, 5 and 0xff. Setting the CPPR to 0 rejects all interrupts, setting it to 0xff allows all interrupts. The values 4 and 5 are used to differentiate IPIs from external interrupts. Setting the CPPR to 5 allows IPIs to be received but not external interrupts. The CPPR emulation in the OPAL XICS implementation only directly supports priorities 0 and 0xff. All other priorities are considered equivalent, and mapped to a single priority value internally. This means when using icp-opal we can not allow IPIs but not externals. This breaks Linux's use of priority values when a CPU is hot unplugged. After migrating IRQs away from the CPU that is being offlined, we set the priority to 5, meaning we still want the offline CPU to receive IPIs. But the effect of the OPAL XICS emulation's use of a single priority value is that all interrupts are rejected by the CPU. With the CPU offline, and not receiving IPIs, we may not be able to wake it up to bring it back online. The first part of the fix is in icp_opal_set_cpu_priority(). CPPR values of 0 to 4 inclusive will correctly cause all interrupts to be rejected, so we pass those CPPR values through to OPAL. However if we are called with a CPPR of 5 or greater, the caller is expecting to be able to allow IPIs but not external interrupts. We know this doesn't work, so instead of rejecting all interrupts we choose the opposite which is to allow all interrupts. This is still not correct behaviour, but we know for the only existing caller (xics_migrate_irqs_away()), that it is the better option. The other part of the fix is in xics_migrate_irqs_away(). Instead of setting priority (CPPR) to 0, and then back to 5 before migrating IRQs, we migrate the IRQs before setting the priority back to 5. This should have no effect on an ICP backend with a working set_priority(), and on icp-opal it means we will keep all interrupts blocked until after we've finished doing the IRQ migration. Additionally we wait for 5ms after doing the migration to make sure there are no IRQs in flight. Fixes: d74361881f0d ("powerpc/xics: Add ICP OPAL backend") Cc: stable@vger.kernel.org # v4.8+ Suggested-by: Michael Ellerman Reported-by: Vaidyanathan Srinivasan Tested-by: Vaidyanathan Srinivasan Signed-off-by: Balbir Singh [mpe: Rewrote comments and change log, change delay to 5ms] Signed-off-by: Michael Ellerman --- arch/powerpc/sysdev/xics/icp-opal.c | 10 ++++++++++ arch/powerpc/sysdev/xics/xics-common.c | 17 ++++++++++++++--- 2 files changed, 24 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c index f9670eabfcfa..b53f80f0b4d8 100644 --- a/arch/powerpc/sysdev/xics/icp-opal.c +++ b/arch/powerpc/sysdev/xics/icp-opal.c @@ -91,6 +91,16 @@ static unsigned int icp_opal_get_irq(void) static void icp_opal_set_cpu_priority(unsigned char cppr) { + /* + * Here be dragons. The caller has asked to allow only IPI's and not + * external interrupts. But OPAL XIVE doesn't support that. So instead + * of allowing no interrupts allow all. That's still not right, but + * currently the only caller who does this is xics_migrate_irqs_away() + * and it works in that case. + */ + if (cppr >= DEFAULT_PRIORITY) + cppr = LOWEST_PRIORITY; + xics_set_base_cppr(cppr); opal_int_set_cppr(cppr); iosync(); diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c index 69d858e51ac7..23efe4e42172 100644 --- a/arch/powerpc/sysdev/xics/xics-common.c +++ b/arch/powerpc/sysdev/xics/xics-common.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -198,9 +199,6 @@ void xics_migrate_irqs_away(void) /* Remove ourselves from the global interrupt queue */ xics_set_cpu_giq(xics_default_distrib_server, 0); - /* Allow IPIs again... */ - icp_ops->set_priority(DEFAULT_PRIORITY); - for_each_irq_desc(virq, desc) { struct irq_chip *chip; long server; @@ -255,6 +253,19 @@ void xics_migrate_irqs_away(void) unlock: raw_spin_unlock_irqrestore(&desc->lock, flags); } + + /* Allow "sufficient" time to drop any inflight IRQ's */ + mdelay(5); + + /* + * Allow IPIs again. This is done at the very end, after migrating all + * interrupts, the expectation is that we'll only get woken up by an IPI + * interrupt beyond this point, but leave externals masked just to be + * safe. If we're using icp-opal this may actually allow all + * interrupts anyway, but that should be OK. + */ + icp_ops->set_priority(DEFAULT_PRIORITY); + } #endif /* CONFIG_HOTPLUG_CPU */ -- cgit v1.2.3 From 672a2c87c83649fb0167202342ce85af9a3b4f1c Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 8 Mar 2017 14:56:05 +0100 Subject: axonram: Fix gendisk handling It is invalid to call del_gendisk() when disk->queue is NULL. Fix error handling in axon_ram_probe() to avoid doing that. Also del_gendisk() does not drop a reference to gendisk allocated by alloc_disk(). That has to be done by put_disk(). Add that call where needed. Reported-by: Dan Carpenter Signed-off-by: Jan Kara Signed-off-by: Jens Axboe --- arch/powerpc/sysdev/axonram.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c index ada29eaed6e2..f523ac883150 100644 --- a/arch/powerpc/sysdev/axonram.c +++ b/arch/powerpc/sysdev/axonram.c @@ -274,7 +274,9 @@ failed: if (bank->disk->major > 0) unregister_blkdev(bank->disk->major, bank->disk->disk_name); - del_gendisk(bank->disk); + if (bank->disk->flags & GENHD_FL_UP) + del_gendisk(bank->disk); + put_disk(bank->disk); } device->dev.platform_data = NULL; if (bank->io_addr != 0) @@ -299,6 +301,7 @@ axon_ram_remove(struct platform_device *device) device_remove_file(&device->dev, &dev_attr_ecc); free_irq(bank->irq_id, device); del_gendisk(bank->disk); + put_disk(bank->disk); iounmap((void __iomem *) bank->io_addr); kfree(bank); -- cgit v1.2.3