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2021-10-04s390/pci: fix zpci_zdev_put() on reserveNiklas Schnelle2-7/+42
Since commit 2a671f77ee49 ("s390/pci: fix use after free of zpci_dev") the reference count of a zpci_dev is incremented between pcibios_add_device() and pcibios_release_device() which was supposed to prevent the zpci_dev from being freed while the common PCI code has access to it. It was missed however that the handling of zPCI availability events assumed that once zpci_zdev_put() was called no later availability event would still see the device. With the previously mentioned commit however this assumption no longer holds and we must make sure that we only drop the initial long-lived reference the zPCI subsystem holds exactly once. Do so by introducing a zpci_device_reserved() function that handles when a device is reserved. Here we make sure the zpci_dev will not be considered for further events by removing it from the zpci_list. This also means that the device actually stays in the ZPCI_FN_STATE_RESERVED state between the time we know it has been reserved and the final reference going away. We thus need to consider it a real state instead of just a conceptual state after the removal. The final cleanup of PCI resources, removal from zbus, and destruction of the IOMMU stays in zpci_release_device() to make sure holders of the reference do see valid data until the release. Fixes: 2a671f77ee49 ("s390/pci: fix use after free of zpci_dev") Cc: stable@vger.kernel.org Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-09-15s390/pci_mmio: fully validate the VMA before calling follow_pte()David Hildenbrand1-2/+2
We should not walk/touch page tables outside of VMA boundaries when holding only the mmap sem in read mode. Evil user space can modify the VMA layout just before this function runs and e.g., trigger races with page table removal code since commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"). find_vma() does not check if the address is >= the VMA start address; use vma_lookup() instead. Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-09-09Merge tag 's390-5.15-2' of ↵Linus Torvalds1-3/+6
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull more s390 updates from Heiko Carstens: "Except for the xpram device driver removal it is all about fixes and cleanups. - Fix topology update on cpu hotplug, so notifiers see expected masks. This bug was uncovered with SCHED_CORE support. - Fix stack unwinding so that the correct number of entries are omitted like expected by common code. This fixes KCSAN selftests. - Add kmemleak annotation to stack_alloc to avoid false positive kmemleak warnings. - Avoid layering violation in common I/O code and don't unregister subchannel from child-drivers. - Remove xpram device driver for which no real use case exists since the kernel is 64 bit only. Also all hypervisors got required support removed in the meantime, which means the xpram device driver is dead code. - Fix -ENODEV handling of clp_get_state in our PCI code. - Enable KFENCE in debug defconfig. - Cleanup hugetlbfs s390 specific Kconfig dependency. - Quite a lot of trivial fixes to get rid of "W=1" warnings, and and other simple cleanups" * tag 's390-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: hugetlbfs: s390 is always 64bit s390/ftrace: remove incorrect __va usage s390/zcrypt: remove incorrect kernel doc indicators scsi: zfcp: fix kernel doc comments s390/sclp: add __nonstring annotation s390/hmcdrv_ftp: fix kernel doc comment s390: remove xpram device driver s390/pci: read clp_list_pci_req only once s390/pci: fix clp_get_state() handling of -ENODEV s390/cio: fix kernel doc comment s390/ctrlchar: fix kernel doc comment s390/con3270: use proper type for tasklet function s390/cpum_cf: move array from header to C file s390/mm: fix kernel doc comments s390/topology: fix topology information when calling cpu hotplug notifiers s390/unwind: use current_frame_address() to unwind current task s390/configs: enable CONFIG_KFENCE in debug_defconfig s390/entry: make oklabel within CHKSTG macro local s390: add kmemleak annotation in stack_alloc() s390/cio: dont unregister subchannel from child-drivers
2021-09-07s390/pci: read clp_list_pci_req only oncePierre Morel1-1/+1
We do not have to reset the fh_list in the loop. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-09-07s390/pci: fix clp_get_state() handling of -ENODEVNiklas Schnelle1-2/+5
With commit cc049eecfb7a ("s390/pci: simplify CLP List PCI handling") clp_get_state() was changed to make use of the new clp_find_pci() helper function to query a specific function. This however returns -ENODEV when the device is not found at all and this error was passed to the caller. It was missed however that the callers actually expect a success return from clp_get_state() if the device is gone. Fix this by handling the -ENODEV return of clp_find_pci() explicitly in clp_get_state() returning success and setting the state parameter to ZPCI_FN_STATE_RESERVED matching the design concept that a PCI function that disappeared must have been resverved elsewhere. For all other error returns continue to just pass them on to the caller. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Fixes: cc049eecfb7a ("s390/pci: simplify CLP List PCI handling") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-09-02Merge tag 'dma-mapping-5.15' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds1-6/+7
Pull dma-mapping updates from Christoph Hellwig: - fix debugfs initialization order (Anthony Iliopoulos) - use memory_intersects() directly (Kefeng Wang) - allow to return specific errors from ->map_sg (Logan Gunthorpe, Martin Oliveira) - turn the dma_map_sg return value into an unsigned int (me) - provide a common global coherent pool іmplementation (me) * tag 'dma-mapping-5.15' of git://git.infradead.org/users/hch/dma-mapping: (31 commits) hexagon: use the generic global coherent pool dma-mapping: make the global coherent pool conditional dma-mapping: add a dma_init_global_coherent helper dma-mapping: simplify dma_init_coherent_memory dma-mapping: allow using the global coherent pool for !ARM ARM/nommu: use the generic dma-direct code for non-coherent devices dma-direct: add support for dma_coherent_default_memory dma-mapping: return an unsigned int from dma_map_sg{,_attrs} dma-mapping: disallow .map_sg operations from returning zero on error dma-mapping: return error code from dma_dummy_map_sg() x86/amd_gart: don't set failed sg dma_address to DMA_MAPPING_ERROR x86/amd_gart: return error code from gart_map_sg() xen: swiotlb: return error code from xen_swiotlb_map_sg() parisc: return error code from .map_sg() ops sparc/iommu: don't set failed sg dma_address to DMA_MAPPING_ERROR sparc/iommu: return error codes from .map_sg() ops s390/pci: don't set failed sg dma_address to DMA_MAPPING_ERROR s390/pci: return error code from s390_dma_map_sg() powerpc/iommu: don't set failed sg dma_address to DMA_MAPPING_ERROR powerpc/iommu: return error code from .map_sg() ops ...
2021-08-30Merge tag 'irq-core-2021-08-30' of ↵Linus Torvalds1-4/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "Updates to the interrupt core and driver subsystems: Core changes: - The usual set of small fixes and improvements all over the place, but nothing stands out MSI changes: - Further consolidation of the PCI/MSI interrupt chip code - Make MSI sysfs code independent of PCI/MSI and expose the MSI interrupts of platform devices in the same way as PCI exposes them. Driver changes: - Support for ARM GICv3 EPPI partitions - Treewide conversion to generic_handle_domain_irq() for all chained interrupt controllers - Conversion to bitmap_zalloc() throughout the irq chip drivers - The usual set of small fixes and improvements" * tag 'irq-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits) platform-msi: Add ABI to show msi_irqs of platform devices genirq/msi: Move MSI sysfs handling from PCI to MSI core genirq/cpuhotplug: Demote debug printk to KERN_DEBUG irqchip/qcom-pdc: Trim unused levels of the interrupt hierarchy irqdomain: Export irq_domain_disconnect_hierarchy() irqchip/gic-v3: Fix priority comparison when non-secure priorities are used irqchip/apple-aic: Fix irq_disable from within irq handlers pinctrl/rockchip: drop the gpio related codes gpio/rockchip: drop irq_gc_lock/irq_gc_unlock for irq set type gpio/rockchip: support next version gpio controller gpio/rockchip: use struct rockchip_gpio_regs for gpio controller gpio/rockchip: add driver for rockchip gpio dt-bindings: gpio: change items restriction of clock for rockchip,gpio-bank pinctrl/rockchip: add pinctrl device to gpio bank struct pinctrl/rockchip: separate struct rockchip_pin_bank to a head file pinctrl/rockchip: always enable clock for gpio controller genirq: Fix kernel doc indentation EDAC/altera: Convert to generic_handle_domain_irq() powerpc: Bulk conversion to generic_handle_domain_irq() nios2: Bulk conversion to generic_handle_domain_irq() ...
2021-08-30Merge tag 's390-5.15-1' of ↵Linus Torvalds6-133/+183
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Heiko Carstens: - Improve ftrace code patching so that stop_machine is not required anymore. This requires a small common code patch acked by Steven Rostedt: https://lore.kernel.org/linux-s390/20210730220741.4da6fdf6@oasis.local.home/ - Enable KCSAN for s390. This comes with a small common code change to fix a compile warning. Acked by Marco Elver: https://lore.kernel.org/r/20210729142811.1309391-1-hca@linux.ibm.com - Add KFENCE support for s390. This also comes with a minimal x86 patch from Marco Elver who said also this can be carried via the s390 tree: https://lore.kernel.org/linux-s390/YQJdarx6XSUQ1tFZ@elver.google.com/ - More changes to prepare the decompressor for relocation. - Enable DAT also for CPU restart path. - Final set of register asm removal patches; leaving only three locations where needed and sane. - Add NNPA, Vector-Packed-Decimal-Enhancement Facility 2, PCI MIO support to hwcaps flags. - Cleanup hwcaps implementation. - Add new instructions to in-kernel disassembler. - Various QDIO cleanups. - Add SCLP debug feature. - Various other cleanups and improvements all over the place. * tag 's390-5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (105 commits) s390: remove SCHED_CORE from defconfigs s390/smp: do not use nodat_stack for secondary CPU start s390/smp: enable DAT before CPU restart callback is called s390: update defconfigs s390/ap: fix state machine hang after failure to enable irq KVM: s390: generate kvm hypercall functions s390/sclp: add tracing of SCLP interactions s390/debug: add early tracing support s390/debug: fix debug area life cycle s390/debug: keep debug data on resize s390/diag: make restart_part2 a local label s390/mm,pageattr: fix walk_pte_level() early exit s390: fix typo in linker script s390: remove do_signal() prototype and do_notify_resume() function s390/crypto: fix all kernel-doc warnings in vfio_ap_ops.c s390/pci: improve DMA translation init and exit s390/pci: simplify CLP List PCI handling s390/pci: handle FH state mismatch only on disable s390/pci: fix misleading rc in clp_set_pci_fn() s390/boot: factor out offset_vmlinux_info() function ...
2021-08-25s390/pci: improve DMA translation init and exitNiklas Schnelle5-36/+61
Currently zpci_dma_init_device()/zpci_dma_exit_device() is called as part of zpci_enable_device()/zpci_disable_device() and errors for zpci_dma_exit_device() are always ignored even if we could abort. Improve upon this by moving zpci_dma_exit_device() out of zpci_disable_device() and check for errors whenever we have a way to abort the current operation. Note that for example in zpci_event_hard_deconfigured() the device is expected to be gone so we really can't abort and proceed even in case of error. Similarly move the cc == 3 special case out of zpci_unregister_ioat() and into the callers allowing to abort when finding an already disabled devices precludes proceeding with the operation. While we are at it log IOAT register/unregister errors in the s390 debugfs log, Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25s390/pci: simplify CLP List PCI handlingNiklas Schnelle2-84/+99
Currently clp_get_state() and clp_refresh_fh() awkwardly use the clp_list_pci() callback mechanism to find the entry for a specific FID and update its zdev, respectively return its state. This is both needlessly complex and means we are always going through the entire PCI function list even if the FID has already been found. Instead lets introduce a clp_find_pci() function to find a specific entry and share the CLP List PCI request handling code with clp_list_pci(). With that in place we can also easily make the function handle a simple out parameter instead of directly altering the zdev allowing easier access to the updated function handle by the caller. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25s390/pci: handle FH state mismatch only on disableNiklas Schnelle2-6/+15
Instead of always treating CLP_RC_SETPCIFN_ALRDY as success and blindly updating the function handle restrict this special handling to the disable case by moving it into zpci_disable_device() and still treating it as an error while also updating the function handle such that a subsequent zpci_disable_device() succeeds or the caller can ignore the error when aborting is not an option such as for zPCI event 0x304. Also print this occurrence to the log such that an admin can tell why a disable operation returned an error. A mismatch between the state of the underlying device and our view of it can naturally happen when the device suddenly enters the error state but we haven't gotten the error notification yet, it must not happen on enable though. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25s390/pci: fix misleading rc in clp_set_pci_fn()Niklas Schnelle2-20/+20
Currently clp_set_pci_fn() always returns 0 as long as the CLP request itself succeeds even if the operation itself returns a response code other than CLP_RC_OK or CLP_RC_SETPCIFN_ALRDY. This is highly misleading because calling code assumes that a zero rc means that the operation was successful. Fix this by returning the response code or cc on failure with the exception of the special handling for CLP_RC_SETPCIFN_ALRDY. Also let's not assume that the returned function handle for CLP_RC_SETPCIFN_ALRDY is 0, we don't need it anyway. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25s390/pci: reset zdev->zbus on registration failureNiklas Schnelle1-1/+2
On failure to register a struct zpci_dev with a struct zpci_bus we left a dangling pointer in zdev->zbus. As zpci_create_device() bails if zpci_bus_device_register() fails this is of no consequence but still bad practice. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-25s390/pci: cleanup resources only if necessaryNiklas Schnelle1-1/+2
It's currently safe to call zpci_cleanup_bus_resources() even if the resources were never created but it makes no sense so check zdev->has_resources before we call zpci_cleanup_bus_resources() in zpci_release_device(). Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-18s390/pci: fix use after free of zpci_devNiklas Schnelle2-0/+11
The struct pci_dev uses reference counting but zPCI assumed erroneously that the last reference would always be the local reference after calling pci_stop_and_remove_bus_device(). This is usually the case but not how reference counting works and thus inherently fragile. In fact one case where this causes a NULL pointer dereference when on an SRIOV device the function 0 was hot unplugged before another function of the same multi-function device. In this case the second function's pdev->sriov->dev reference keeps the struct pci_dev of function 0 alive even after the unplug. This bug was previously hidden by the fact that we were leaking the struct pci_dev which in turn means that it always outlived the struct zpci_dev. This was fixed in commit 0b13525c20fe ("s390/pci: fix leak of PCI device structure") exposing the broken behavior. Fix this by accounting for the long living reference a struct pci_dev has to its underlying struct zpci_dev via the zbus->function[] array and only release that in pcibios_release_device() ensuring that the struct pci_dev is not left with a dangling reference. This is a minimal fix in the future it would probably better to use fine grained reference counting for struct zpci_dev. Fixes: 05bc1be6db4b2 ("s390/pci: create zPCI bus") Cc: stable@vger.kernel.org Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-10s390/pci: Do not mask MSI[-X] entries on teardownThomas Gleixner1-4/+0
The PCI core already ensures that the MSI[-X] state is correct when MSI[-X] is disabled. For MSI the reset state is all entries unmasked and for MSI-X all vectors are masked. S390 masks all MSI entries and masks the already masked MSI-X entries again. Remove it and let the device in the correct state. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Niklas Schnelle <schnelle@linux.ibm.com> Tested-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Acked-by: Niklas Schnelle <schnelle@linux.ibm.com> Link: https://lore.kernel.org/r/20210729222542.939798136@linutronix.de
2021-08-09s390/pci: don't set failed sg dma_address to DMA_MAPPING_ERRORLogan Gunthorpe1-1/+0
Setting the ->dma_address to DMA_MAPPING_ERROR is not part of the ->map_sg calling convention, so remove it. Link: https://lore.kernel.org/linux-mips/20210716063241.GC13345@lst.de/ Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-08-09s390/pci: return error code from s390_dma_map_sg()Martin Oliveira1-5/+7
The .map_sg() op now expects an error code instead of zero on failure. So propagate the error from __s390_dma_map_sg() up. __s390_dma_map_sg() returns either -ENOMEM on allocation failure or -EINVAL which is the same as what's expected by dma_map_sgtable(). Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Acked-by: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-07-27s390: make PCI mio support a machine flagNiklas Schnelle1-3/+2
Kernel support for the newer PCI mio instructions can be toggled off with the pci=nomio command line option which needs to integrate with common code PCI option parsing. However this option then toggles static branches which can't be toggled yet in an early_param() call. Thus commit 9964f396f1d0 ("s390: fix setting of mio addressing control") moved toggling the static branches to the PCI init routine. With this setup however we can't check for mio support outside the PCI code during early boot, i.e. before switching the static branches, which we need to be able to export this as an ELF HWCAP. Improve on this by turning mio availability into a machine flag that gets initially set based on CONFIG_PCI and the facility bit and gets toggled off if pci=nomio is found during PCI option parsing allowing simple access to this machine flag after early init. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-06-28s390/pci: add zpci_set_irq()/zpci_clear_irq()Niklas Schnelle1-10/+36
Pull the directed vs floating IRQ check into common zpci_set_irq()/zpci_clear_irq() functions and expose them for the rest of the zPCI subsystem. Furthermore we add a zdev flag bit to easily check if IRQs are registered. This is needed for use in resetting a zPCI function. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-06-18s390/pci: use register pair instead of register asmNiklas Schnelle2-45/+34
Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-04-30s390/pci: handle stale deconfiguration eventsNiklas Schnelle1-8/+18
The PCIs event with PEC 0x0303 or 0x0304 are a request to deconfigure a PCI function, respectively an indication that it was already deconfigured by the platform. If such an event is queued during boot it may happen that the platform has already adjusted the configuration flag of the relevant function in the CLP List PCI Functions result. In this case we might not have configured the PCI function at all and should thus ignore the event. Note that no locking is necessary as event handling only starts after we have fully initialized the zPCI subsystem and scanned all PCI devices listed in the CLP result. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-30s390/pci: rename zpci_configure_device()Niklas Schnelle2-5/+7
With zpci_configure_device() now always called on a device that has already been configured on the platform level its name has become misleading. Rename it to zpci_scan_configured_device() to signify that the function now only handles the correct scanning of a newly configured PCI function taking care of the special handling necessary for function 0 and functions parked waiting for a PCI bus that can't be created without first seeing function 0. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-20s390/pci: expose a PCI device's UID as its indexNiklas Schnelle1-0/+35
On s390 each PCI device has a user-defined ID (UID) exposed under /sys/bus/pci/devices/<dev>/uid. This ID was designed to serve as the PCI device's primary index and to match the device within Linux to the device configured in the hypervisor. To serve as a primary identifier the UID must be unique within the Linux instance, this is guaranteed by the platform if and only if the UID Uniqueness Checking flag is set within the CLP List PCI Functions response. In this sense the UID serves an analogous function as the SMBIOS instance number or ACPI index exposed as the "index" respectively "acpi_index" device attributes and used by e.g. systemd to set interface names. As s390 does not use and will likely never use ACPI nor SMBIOS there is no conflict and we can just expose the UID under the "index" attribute whenever UID Uniqueness Checking is active and get systemd's interface naming support for free. Link: https://lore.kernel.org/lkml/20210412135905.1434249-1-schnelle@linux.ibm.com/ Acked-by: Viktor Mihajlovski <mihajlov@linux.ibm.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Narendra K <narendra_k@dell.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: narrow scope of zpci_configure_device()Niklas Schnelle1-12/+3
Currently zpci_configure_device() can be called on a zPCI function in two completely different states. Either the underlying zPCI function has already been configured by the platform and we are only doing the scanning to get it usable by Linux drivers. Or the underlying function is in Standby and we first do an SCLP to get it configured. This makes zpci_configure_device() harder to reason about. Since calling zpci_configure_device() on a function in Standby only happens in enable_slot() simply pull out the SCLP call and setting of zdev->state and thus call zpci_configure_device() under the same circumstances as in the event handling code. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: separate zbus registration from scanningNiklas Schnelle4-29/+32
Now that the zbus can be created without being scanned we can go one step further and make registering a device to a zbus independent from scanning it. This way the zbus handling becomes much more natural in that functions can be registered on the zbus to be scanned later more closely resembling the handling of both real PCI hardware and other virtual PCI busses like Hyper-V's virtual PCI bus (see for example drivers/pci/controller/pci-hyperv.c:create_root_hv_pci_bus()). Having zbus registration separate from scanning allows us to return fully initialized but still disabled zdevs from zpci_create_device() which can then be configured just as we would configure a zdev from standby (minus the SCLP Configure already done by the platform). There is still the exception that a PCI function with non-zero devfn can be plugged before its PCI bus, which depends on the function with zero devfn, is created. In this case the zdev returend from zpci_create_device() is still missing its bus, hotplug slot, and resources which need to be created later but at least it doesn't wait in the enabled state and can otherwise be treated as initialized. With this we also separate the initial PCI scan using CLP List PCI Functions into two phases. In the CLP loop's callback we only register each function with a virtual zbus creating the latter as needed. Then, after we have built this virtual PCI topology based on our list of zbusses, we can make use of the common code functionality to scan each complete zbus as a separate child bus. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: use mutex not spinlock for zbus listNiklas Schnelle1-7/+7
In a later change we will first collect all PCI functions from the CLP List PCI functions call, then register them to/creating the relevant zbus. Then only after we've created our virtual bus structure will we scan all zbusses iterating over the zbus list. Since scanning is relatively slow a spinlock is a bad fit for protecting the loop over the devices on the zbus. Furthermore doing the probing on the bus we need to use pci_lock_rescan_remove() as devices are added to the PCI subsystem and that is a mutex which can't be locked nested inside a spinlock section. Note that the contention of this lock should be very low either way as zbusses are only added/removed concurrently on hotplug events. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: separate zbus creation from scanningNiklas Schnelle3-96/+175
In the existing code the creation of the PCI bus and the scanning of function zero all happens in zpci_scan_bus(). This in turn requires functions to be enabled and their resources to be available before the PCI bus is even created. This not only means that functions are enabled long before they are actually made available to the common PCI subsystem. In case of functions with non-zero devfn which appeared before the function with devfn zero they can wait arbitrarily long in this enabled but not scanned state. Fix this by separating the creation of the PCI bus from scanning it and only prepare, that is enable and setup MMIO bus resources, functions just before they are scanned. As they may be scanned multiple times track if we already created resources in the zdev. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: do more bus setup in zpci_bus_scan()Niklas Schnelle1-13/+20
Pull setting the maximum bus speed and multifunction attribute into zpci_bus_scan() in preparation for handling bus creation separately from scanning the bus. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12s390/pci: introduce zpci_bus_scan_device()Niklas Schnelle3-17/+28
To match zpci_bus_scan_device() and the PCI common code terminology and to remove some code duplication, we pull the multiple uses of pci_scan_single_device() into a function. For now this has the side effect of adding each device to the PCI bus separately and locking and unlocking the rescan/remove lock for each instead of just once per bus. This is clearly less efficient but provides a correct intermediate behavior until a follow on change does both the adding and scanning only once per bus. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-05s390/pci: expose UID uniqueness guaranteeNiklas Schnelle1-0/+9
On s390 each PCI device has a user-defined ID (UID) exposed under /sys/bus/pci/devices/<dev>/uid. This ID was designed to serve as the PCI device's primary index and to match the device within Linux to the device configured in the hypervisor. To serve as a primary identifier the UID must be unique within the Linux instance, this is guaranteed by the platform if and only if the UID Uniqueness Checking flag is set within the CLP List PCI Functions response. While the UID has been exposed to userspace since commit ac4995b9d570 ("s390/pci: add some new arch specific pci attributes") whether or not the platform guarantees its uniqueness for the lifetime of the Linux instance while defined is not visible from userspace. Remedy this by exposing this as a per device attribute at /sys/bus/pci/devices/<dev>/uid_is_unique Keeping this a per device attribute allows for maximum flexibility if we ever end up with some devices not having a UID or not enjoying the guaranteed uniqueness. Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Viktor Mihajlovski <mihajlov@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-28s390/pci: fix DMA cleanup on hard deconfigureNiklas Schnelle1-6/+5
In commit dee60c0dbc83 ("s390/pci: add zpci_event_hard_deconfigured()") we added a zdev_enabled() check to what was previously an uncoditional call to zpci_disable_device(). There are two problems with that. Firstly zpci_had_deconfigured() is only called on event 0x0304 for which the device is always already disabled by the platform so it is always false. Secondly zpci_disable_device() not only disables the device but also calls zpci_dma_exit_device() which is thus not called and we leak the DMA tables. Fix this by calling zpci_disable_device() unconditionally to perform Linux side cleanup including the freeing of DMA tables. Fixes: dee60c0dbc83 ("s390/pci: add zpci_event_hard_deconfigured()") Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-22s390/pci: move zpci_remove_device() to bus codeNiklas Schnelle4-36/+38
The zpci_remove_device() function removes the device from the PCI common code core which is an operation dealing primarily with the zbus and PCI bus code. With that and to match an upcoming refactoring of the symmetric scanning part move it to the bus code. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-22s390/pci: unify de-/configure for slots and eventsNiklas Schnelle2-38/+95
A zPCI event with PEC 0x0301 for an existing zPCI device goes through the same actions as enable_slot(). Similarly a zPCI event with PEC 0x0303 does the same steps as disable_slot(). We can thus unify both actions as zpci_configure_device() respectively zpci_deconfigure_device(). Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-22s390/pci: add zpci_event_hard_deconfigured()Niklas Schnelle1-15/+24
Extract the handling of PEC 0x0304 into a function and make sure we only attempt to disable the function if it is enabled. Also check for errors returned by zpci_disable_device() and leave the function alone if there are any. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-22s390/pci: deconfigure device on releaseNiklas Schnelle1-0/+5
When zpci_release_device() is called on a zPCI function that is still configured it would not be deconfigured. Until now this hasn't caused any problems because zpci_zdev_put() is only ever called for devices in Standby or Reserved. Fix it by adding sclp_pci_deconfigure() to the switch when in Configured state. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-22s390/pci: refactor zpci function statesNiklas Schnelle1-6/+4
The current zdev->state mixes the configuration states supported by CLP with an additional Online state which is used inconsistently to include enabled zPCI functions which are not yet visible to the common PCI subsytem. In preparation for a clean separation between architected configuration states and fine grained function states remove the Online function state. Where we previously checked for Online it is more accurate to check if the function is enabled to avoid an edge case where a disabled device was still treated as Online. This also simplifies checks whether a function is configured as this is now directly reflected by its function state. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-15s390/pci: fix leak of PCI device structureNiklas Schnelle2-16/+30
In commit 05bc1be6db4b2 ("s390/pci: create zPCI bus") we removed the pci_dev_put() call matching the earlier pci_get_slot() done as part of __zpci_event_availability(). This was based on the wrong understanding that the device_put() done as part of pci_destroy_device() would counter the pci_get_slot() when it only counters the initial reference. This same understanding and existing bad example also lead to not doing a pci_dev_put() in zpci_remove_device(). Since releasing the PCI devices, unlike releasing the PCI slot, does not print any debug message for testing I added one in pci_release_dev(). This revealed that we are indeed leaking the PCI device on PCI hotunplug. Further testing also revealed another missing pci_dev_put() in disable_slot(). Fix this by adding the missing pci_dev_put() in disable_slot() and fix zpci_remove_device() with the correct pci_dev_put() calls. Also instead of calling pci_get_slot() in __zpci_event_availability() to determine if a PCI device is registered and then doing the same again in zpci_remove_device() do this once in zpci_remove_device() which makes sure that the pdev in __zpci_event_availability() is only used for the result of pci_scan_single_device() which does not need a reference count decremnt as its ownership goes to the PCI bus. Also move the check if zdev->zbus->bus is set into zpci_remove_device() since it may be that we're removing a device with devfn != 0 which never had a PCI bus. So we can still set the pdev->error_state to indicate that the device is not usable anymore, add a flag to set the error state. Fixes: 05bc1be6db4b2 ("s390/pci: create zPCI bus") Cc: <stable@vger.kernel.org> # 5.8+: e1bff843cde6 s390/pci: remove superfluous zdev->zbus check Cc: <stable@vger.kernel.org> # 5.8+: ba764dd703fe s390/pci: refactor zpci_create_device() Cc: <stable@vger.kernel.org> # 5.8+ Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-02-21Merge tag 's390-5.12-1' of ↵Linus Torvalds3-56/+47
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Vasily Gorbik: - Convert to using the generic entry infrastructure. - Add vdso time namespace support. - Switch s390 and alpha to 64-bit ino_t. As discussed at https://lore.kernel.org/linux-mm/YCV7QiyoweJwvN+m@osiris/ - Get rid of expensive stck (store clock) usages where possible. Utilize cpu alternatives to patch stckf when supported. - Make tod_clock usage less error prone by converting it to a union and rework code which is using it. - Machine check handler fixes and cleanups. - Drop couple of minor inline asm optimizations to fix clang build. - Default configs changes notably to make libvirt happy. - Various changes to rework and improve qdio code. - Other small various fixes and improvements all over the code. * tag 's390-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (68 commits) s390/qdio: remove 'merge_pending' mechanism s390/qdio: improve handling of PENDING buffers for QEBSM devices s390/qdio: rework q->qdio_error indication s390/qdio: inline qdio_kick_handler() s390/time: remove get_tod_clock_ext() s390/crypto: use store_tod_clock_ext() s390/hypfs: use store_tod_clock_ext() s390/debug: use union tod_clock s390/kvm: use union tod_clock s390/vdso: use union tod_clock s390/time: convert tod_clock_base to union s390/time: introduce new store_tod_clock_ext() s390/time: rename store_tod_clock_ext() and use union tod_clock s390/time: introduce union tod_clock s390,alpha: switch to 64-bit ino_t s390: split cleanup_sie s390: use r13 in cleanup_sie as temp register s390: fix kernel asce loading when sie is interrupted s390: add stack for machine check handler s390: use WRITE_ONCE when re-allocating async stack ...
2021-02-09s390/pci: refactor zpci_create_device()Niklas Schnelle3-55/+46
Currently zpci_create_device() is only called in clp_add_pci_device() which allocates the memory for the struct zpci_dev being created. There is little separation of concerns as only both functions together can create a zpci_dev and the only CLP specific code in clp_add_pci_device() is a call to clp_query_pci_fn(). Improve this by removing clp_add_pci_device() and refactor zpci_create_device() such that it alone creates and initializes the zpci_dev given the FID and Function Handle. For this we need to make clp_query_pci_fn() non-static. While at it remove the function handle parameter since we can just take that from the zpci_dev. Also move adding to the zpci_list to after the zdev has been fully created which eliminates a window where a partially initialized zdev can be found by get_zdev_by_fid(). Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-02-09mm: provide a saner PTE walking API for modulesPaolo Bonzini1-2/+2
Currently, the follow_pfn function is exported for modules but follow_pte is not. However, follow_pfn is very easy to misuse, because it does not provide protections (so most of its callers assume the page is writable!) and because it returns after having already unlocked the page table lock. Provide instead a simplified version of follow_pte that does not have the pmdpp and range arguments. The older version survives as follow_invalidate_pte() for use by fs/dax.c. Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-27s390/pci: remove superfluous zdev->zbus checkNiklas Schnelle1-1/+1
Checking zdev->zbus for NULL in __zpci_event_availability() is superfluous as it can never be NULL at this point. While harmless this check causes smatch warnings because we later access zdev->zbus with only having checked zdev != NULL which is sufficient. The reason zdev->zbus can never be NULL is since with zdev != NULL given we know the zdev came from get_zdev_by_fid() and thus the zpci_list. Now on first glance at zpci_create_device() one may assume that there is a window where the zdev is in the list without a zdev, however this window can't overlap with __zpci_event_availability() as zpci_create_device() either runs on the same kthread as part of availability events, or during the initial CLP List PCI at which point the __zpci_event_availability() is not yet called as zPCI is not yet initialized. Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-12-15mm: simplify follow_pte{,pmd}Christoph Hellwig1-2/+2
Merge __follow_pte_pmd, follow_pte_pmd and follow_pte into a single follow_pte function and just pass two additional NULL arguments for the two previous follow_pte callers. [sfr@canb.auug.org.au: merge fix for "s390/pci: remove races against pte updates"] Link: https://lkml.kernel.org/r/20201111221254.7f6a3658@canb.auug.org.au Link: https://lkml.kernel.org/r/20201029101432.47011-3-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-14Merge tag 'sched-core-2020-12-14' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Thomas Gleixner: - migrate_disable/enable() support which originates from the RT tree and is now a prerequisite for the new preemptible kmap_local() API which aims to replace kmap_atomic(). - A fair amount of topology and NUMA related improvements - Improvements for the frequency invariant calculations - Enhanced robustness for the global CPU priority tracking and decision making - The usual small fixes and enhancements all over the place * tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits) sched/fair: Trivial correction of the newidle_balance() comment sched/fair: Clear SMT siblings after determining the core is not idle sched: Fix kernel-doc markup x86: Print ratio freq_max/freq_base used in frequency invariance calculations x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC x86, sched: Calculate frequency invariance for AMD systems irq_work: Optimize irq_work_single() smp: Cleanup smp_call_function*() irq_work: Cleanup sched: Limit the amount of NUMA imbalance that can exist at fork time sched/numa: Allow a floating imbalance between NUMA nodes sched: Avoid unnecessary calculation of load imbalance at clone time sched/numa: Rename nr_running and break out the magic number sched: Make migrate_disable/enable() independent of RT sched/topology: Condition EAS enablement on FIE support arm64: Rebuild sched domains on invariance status changes sched/topology,schedutil: Wrap sched domains rebuild sched/uclamp: Allow to reset a task uclamp constraint value sched/core: Fix typos in comments Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug ...
2020-12-14Merge tag 's390-5.11-1' of ↵Linus Torvalds2-48/+60
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Heiko Carstens: - Add support for the hugetlb_cma command line option to allocate gigantic hugepages using CMA - Add arch_get_random_long() support. - Add ap bus userspace notifications. - Increase default size of vmalloc area to 512GB and otherwise let it increase dynamically by the size of physical memory. This should fix all occurrences where the vmalloc area was not large enough. - Completely get rid of set_fs() (aka select SET_FS) and rework address space handling while doing that; making address space handling much more simple. - Reimplement getcpu vdso syscall in C. - Add support for extended SCLP responses (> 4k). This allows e.g. to handle also potential large system configurations. - Simplify KASAN by removing 3-level page table support and only supporting 4-levels from now on. - Improve debug-ability of the kernel decompressor code, which now prints also stack traces and symbols in case of problems to the console. - Remove more power management leftovers. - Other various fixes and improvements all over the place. * tag 's390-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (62 commits) s390/mm: add support to allocate gigantic hugepages using CMA s390/crypto: add arch_get_random_long() support s390/smp: perform initial CPU reset also for SMT siblings s390/mm: use invalid asce for user space when switching to init_mm s390/idle: fix accounting with machine checks s390/idle: add missing mt_cycles calculation s390/boot: add build-id to decompressor s390/kexec_file: fix diag308 subcode when loading crash kernel s390/cio: fix use-after-free in ccw_device_destroy_console s390/cio: remove pm support from ccw bus driver s390/cio: remove pm support from css-bus driver s390/cio: remove pm support from IO subchannel drivers s390/cio: remove pm support from chsc subchannel driver s390/vmur: remove unused pm related functions s390/tape: remove unsupported PM functions s390/cio: remove pm support from eadm-sch drivers s390: remove pm support from console drivers s390/dasd: remove unused pm related functions s390/zfcp: remove pm support from zfcp driver s390/ap: let bus_register() add the AP bus sysfs attributes ...
2020-12-02s390/pci: fix CPU address in MSI for directed IRQAlexander Gordeev1-3/+11
The directed MSIs are delivered to CPUs whose address is written to the MSI message address. The current code assumes that a CPU logical number (as it is seen by the kernel) is also the CPU address. The above assumption is not correct, as the CPU address is rather the value returned by STAP instruction. That value does not necessarily match the kernel logical CPU number. Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts") Cc: <stable@vger.kernel.org> # v5.2+ Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-27Merge branch 'linus' into sched/core, to resolve semantic conflictIngo Molnar1-0/+4
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-11-24smp: Cleanup smp_call_function*()Peter Zijlstra1-3/+1
Get rid of the __call_single_node union and cleanup the API a little to avoid external code relying on the structure layout as much. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
2020-11-23s390/mm: remove set_fs / rework address space handlingHeiko Carstens1-6/+0
Remove set_fs support from s390. With doing this rework address space handling and simplify it. As a result address spaces are now setup like this: CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE ----------------------------|-----------|-----------|----------- user space | user | user | kernel kernel, normal execution | kernel | user | kernel kernel, kvm guest execution | gmap | user | kernel To achieve this the getcpu vdso syscall is removed in order to avoid secondary address mode and a separate vdso address space in for user space. The getcpu vdso syscall will be implemented differently with a subsequent patch. The kernel accesses user space always via secondary address space. This happens in different ways: - with mvcos in home space mode and directly read/write to secondary address space - with mvcs/mvcp in primary space mode and copy from primary space to secondary space or vice versa - with e.g. cs in secondary space mode and access secondary space Switching translation modes happens with sacf before and after instructions which access user space, like before. Lazy handling of control register reloading is removed in the hope to make everything simpler, but at the cost of making kernel entry and exit a bit slower. That is: on kernel entry the primary asce is always changed to contain the kernel asce, and on kernel exit the primary asce is changed again so it contains the user asce. In kernel mode there is only one exception to the primary asce: when kvm guests are executed the primary asce contains the gmap asce (which describes the guest address space). The primary asce is reset to kernel asce whenever kvm guest execution is interrupted, so that this doesn't has to be taken into account for any user space accesses. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-18s390/pci: inform when missing required facilitiesNiklas Schnelle1-1/+3
when we're missing the necessary machine facilities zPCI can not function. Until now it would silently fail to be initialized, add an informational print. Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>