kernel/linux.git/arch/powerpc/sysdev/xics/icp-native.c, branch linux-4.4.y

powerpc: Make doorbell check preemption safe

2015-06-16T22:01:03+00:00

Doorbell can be used to cause ipi on cpus which are sibling threads on the same core. So icp_native_cause_ipi checks if the destination cpu is a sibling thread of the current cpu and uses doorbell in such cases. But while running with CONFIG_PREEMPT=y, since this section is preemtible, we can run into issues if after we check if the destination cpu is a sibling cpu, the task gets migrated from a sibling cpu to a cpu on another core. Fix this by using get_cpu()/ put_cpu() Signed-off-by: Shreyas B. Prabhu Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman

powerpc/powernv: Don't call generic code on offline cpus

2014-09-25T13:14:50+00:00

On PowerNV platforms, when a CPU is offline, we put it into nap mode. It's possible that the CPU wakes up from nap mode while it is still offline due to a stray IPI. A misdirected device interrupt could also potentially cause it to wake up. In that circumstance, we need to clear the interrupt so that the CPU can go back to nap mode. In the past the clearing of the interrupt was accomplished by briefly enabling interrupts and allowing the normal interrupt handling code (do_IRQ() etc.) to handle the interrupt. This has the problem that this code calls irq_enter() and irq_exit(), which call functions such as account_system_vtime() which use RCU internally. Use of RCU is not permitted on offline CPUs and will trigger errors if RCU checking is enabled. To avoid calling into any generic code which might use RCU, we adopt a different method of clearing interrupts on offline CPUs. Since we are on the PowerNV platform, we know that the system interrupt controller is a XICS being driven directly (i.e. not via hcalls) by the kernel. Hence this adds a new icp_native_flush_interrupt() function to the native-mode XICS driver and arranges to call that when an offline CPU is woken from nap. This new function reads the interrupt from the XICS. If it is an IPI, it clears the IPI; if it is a device interrupt, it prints a warning and disables the source. Then it does the end-of-interrupt processing for the interrupt. The other thing that briefly enabling interrupts did was to check and clear the irq_happened flag in this CPU's PACA. Therefore, after flushing the interrupt from the XICS, we also clear all bits except the PACA_IRQ_HARD_DIS (interrupts are hard disabled) bit from the irq_happened flag. The PACA_IRQ_HARD_DIS flag is set by power7_nap() and is left set to indicate that interrupts are hard disabled. This means we then have to ignore that flag in power7_nap(), which is reasonable since it doesn't indicate that any interrupt event needs servicing. Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman

powerpc/powernv: Enable POWER8 doorbell IPIs

2014-06-11T07:05:12+00:00

This patch enables POWER8 doorbell IPIs on powernv. Since doorbells can only IPI within a core, we test to see when we can use doorbells and if not we fall back to XICS. This also enables hypervisor doorbells to wakeup us up from nap/sleep via the LPCR PECEDH bit. Based on tests by Anton, the best case IPI latency between two threads dropped from 894ns to 512ns. Signed-off-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt

powerpc: Add some endian annotations to time and xics code

2013-08-14T05:33:24+00:00

Fix a couple of sparse warnings. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

Merge tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2013-05-05T21:47:31+00:00

Pull kvm updates from Gleb Natapov: "Highlights of the updates are: general: - new emulated device API - legacy device assignment is now optional - irqfd interface is more generic and can be shared between arches x86: - VMCS shadow support and other nested VMX improvements - APIC virtualization and Posted Interrupt hardware support - Optimize mmio spte zapping ppc: - BookE: in-kernel MPIC emulation with irqfd support - Book3S: in-kernel XICS emulation (incomplete) - Book3S: HV: migration fixes - BookE: more debug support preparation - BookE: e6500 support ARM: - reworking of Hyp idmaps s390: - ioeventfd for virtio-ccw And many other bug fixes, cleanups and improvements" * tag 'kvm-3.10-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits) kvm: Add compat_ioctl for device control API KVM: x86: Account for failing enable_irq_window for NMI window request KVM: PPC: Book3S: Add API for in-kernel XICS emulation kvm/ppc/mpic: fix missing unlock in set_base_addr() kvm/ppc: Hold srcu lock when calling kvm_io_bus_read/write kvm/ppc/mpic: remove users kvm/ppc/mpic: fix mmio region lists when multiple guests used kvm/ppc/mpic: remove default routes from documentation kvm: KVM_CAP_IOMMU only available with device assignment ARM: KVM: iterate over all CPUs for CPU compatibility check KVM: ARM: Fix spelling in error message ARM: KVM: define KVM_ARM_MAX_VCPUS unconditionally KVM: ARM: Fix API documentation for ONE_REG encoding ARM: KVM: promote vfp_host pointer to generic host cpu context ARM: KVM: add architecture specific hook for capabilities ARM: KVM: perform HYP initilization for hotplugged CPUs ARM: KVM: switch to a dual-step HYP init code ARM: KVM: rework HYP page table freeing ARM: KVM: enforce maximum size for identity mapped code ARM: KVM: move to a KVM provided HYP idmap ...

KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVM

2013-04-26T18:27:31+00:00

Currently, we wake up a CPU by sending a host IPI with smp_send_reschedule() to thread 0 of that core, which will take all threads out of the guest, and cause them to re-evaluate their interrupt status on the way back in. This adds a mechanism to differentiate real host IPIs from IPIs sent by KVM for guest threads to poke each other, in order to target the guest threads precisely when possible and avoid that global switch of the core to host state. We then use this new facility in the in-kernel XICS code. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf

powerpc/powernv: Patch MSI EOI handler on P8

2013-04-26T06:09:59+00:00

The EOI handler of MSI/MSI-X interrupts for P8 (PHB3) need additional steps to handle the P/Q bits in IVE before EOIing the corresponding interrupt. The patch changes the EOI handler to cover that. we have individual IRQ chip in each PHB instance. During the MSI IRQ setup time, the IRQ chip is copied over from the original one for that IRQ, and the EOI handler is patched with the one that will handle the P/Q bits (As Ben suggested). Signed-off-by: Gavin Shan Signed-off-by: Benjamin Herrenschmidt

irqdomain: Eliminate dedicated radix lookup functions

2012-07-11T15:16:00+00:00

In preparation to remove the slow revmap path, eliminate the public radix revmap lookup functions. This simplifies the code and makes the slowpath removal patch a lot simpler. Signed-off-by: Grant Likely Cc: Paul Mundt Cc: Benjamin Herrenschmidt Cc: Thomas Gleixner Cc: Rob Herring

powerpc/xics: Add __init to marker icp_native_init()

2011-09-19T23:20:02+00:00

This should fix the following warning: LD arch/powerpc/sysdev/xics/built-in.o WARNING: arch/powerpc/sysdev/xics/built-in.o(.text+0x1310): Section mismatch in reference from the function .icp_native_init() to the function .init.text:.icp_native_init_one_node() The function .icp_native_init() references the function __init .icp_native_init_one_node(). This is often because .icp_native_init lacks a __init annotation or the annotation of .icp_native_init_one_node is wrong. icp_native_init() is only referenced in `arch/powerpc/sysdev/xics/xics-common.c' by xics_init() which is itself marked with __init. = not built-tested = Reported-by: Timur Tabi Signed-off-by: Arnaud Lacombe Signed-off-by: Benjamin Herrenschmidt

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2011-07-25T20:56:39+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) fs: Merge split strings treewide: fix potentially dangerous trailing ';' in #defined values/expressions uwb: Fix misspelling of neighbourhood in comment net, netfilter: Remove redundant goto in ebt_ulog_packet trivial: don't touch files that are removed in the staging tree lib/vsprintf: replace link to Draft by final RFC number doc: Kconfig: `to be' -> `be' doc: Kconfig: Typo: square -> squared doc: Konfig: Documentation/power/{pm => apm-acpi}.txt drivers/net: static should be at beginning of declaration drivers/media: static should be at beginning of declaration drivers/i2c: static should be at beginning of declaration XTENSA: static should be at beginning of declaration SH: static should be at beginning of declaration MIPS: static should be at beginning of declaration ARM: static should be at beginning of declaration rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check Update my e-mail address PCIe ASPM: forcedly -> forcibly gma500: push through device driver tree ... Fix up trivial conflicts: - arch/arm/mach-ep93xx/dma-m2p.c (deleted) - drivers/gpio/gpio-ep93xx.c (renamed and context nearby) - drivers/net/r8169.c (just context changes)