Changes since v7? * Removed the memory allocation in the task_work stuff. * More user-friendly and easier on the eye, * Switched the irq-mask testing in the arch code to be safe before&after Julien's GIC PMR series. Specific changes are noted in each patch. This series aims to wire-up arm64's fancy new software-NMI notifications for firmware-first RAS. These need to use the estatus-queue, which is also needed for notifications via emulated-SError. All of these things take the 'in_nmi()' path through ghes_copy_tofrom_phys(), and so will deadlock if they can interact, which they might. To that end, this series removes the in_nmi() stuff from ghes.c. Locks are pushed out to the notification helpers, and fixmap entries are passed in to the code that needs them. This means the estatus-queue users can interrupt each other however they like. While doing this there is a fair amount of cleanup, which is (now) at the beginning of the series. NMIlike notifications interrupting ghes_probe() can go wrong for three different reasons. CPER record blocks greater than PAGE_SIZE dont' work. The estatus-pool allocation is simplified and the silent-flag/oops-begin is removed. Nothing in this series is intended as fixes, as its all cleanup or never-worked. ----------%<---------- The earlier boiler-plate: What's SDEI? Its ARM's "Software Delegated Exception Interface" [0]. It's used by firmware to tell the OS about firmware-first RAS events. These Software exceptions can interrupt anything, so I describe them as NMI-like. They aren't the only NMI-like way to notify the OS about firmware-first RAS events, the ACPI spec also defines 'NOTFIY_SEA' and 'NOTIFY_SEI'. (Acronyms: SEA, Synchronous External Abort. The CPU requested some memory, but the owner of that memory said no. These are always synchronous with the instruction that caused them. SEI, System-Error Interrupt, commonly called SError. This is an asynchronous external abort, the memory-owner didn't say no at the right point. Collectively these things are called external-aborts How is firmware involved? It traps these and re-injects them into the kernel once its written the CPER records). APEI's GHES code only expects one source of NMI. If a platform implements more than one of these mechanisms, APEI needs to handle the interaction. 'SEA' and 'SEI' can interact as 'SEI' is asynchronous. SDEI can interact with itself: its exceptions can be 'normal' or 'critical', and firmware could use both types for RAS. (errors using normal, 'panic-now' using critical). ----------%<---------- This series is base on v5.0-rc1, and can be retrieved from: git://linux-arm.org/linux-jm.git -b apei_ioremap_rework/v8 Known issues: * ghes_copy_tofrom_phys() already takes a lock in NMI context, this series moves that around, and makes sure we never try to take the same lock from different NMIlike notifications. Since the switch to queued spinlocks it looks like the kernel can only be 4 context's deep in spinlock, which arm64 could exceed as it doesn't have a single architected NMI. This would be fixed by dropping back to test-and-set when the nesting gets too deep: lore.kernel.org/r/1548215351-18896-1-git-send-email-longman@xxxxxxxxxx * Taking an NMI from a KVM guest on arm64 with VHE leaves HCR_EL2.TGE clear, meaning AT and TLBI point at the guest, and PAN/UAO are squiffy. Only TLBI matters for APEI, and this is fixed by Julien's patch: http://lore.kernel.org/r/1548084825-8803-2-git-send-email-julien.thierry@xxxxxxx * Linux ignores the physical address mask, meaning it doesn't call memory_failure() on all the affected pages if firmware or hypervisor believe in a different page size. Easy to hit on arm64, (easy to fix too, it just conflicts with this series) [v7] https://lore.kernel.org/linux-arm-kernel/20181203180613.228133-1-james.morse@xxxxxxx/ [v6] https://www.spinics.net/lists/linux-acpi/msg84228.html [v5] https://www.spinics.net/lists/linux-acpi/msg82993.html [v4] https://www.spinics.net/lists/arm-kernel/msg653078.html [v3] https://www.spinics.net/lists/arm-kernel/msg649230.html [0] https://static.docs.arm.com/den0054/a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf James Morse (26): ACPI / APEI: Don't wait to serialise with oops messages when panic()ing ACPI / APEI: Remove silent flag from ghes_read_estatus() ACPI / APEI: Switch estatus pool to use vmalloc memory ACPI / APEI: Make hest.c manage the estatus memory pool ACPI / APEI: Make estatus pool allocation a static size ACPI / APEI: Don't store CPER records physical address in struct ghes ACPI / APEI: Remove spurious GHES_TO_CLEAR check ACPI / APEI: Don't update struct ghes' flags in read/clear estatus ACPI / APEI: Generalise the estatus queue's notify code ACPI / APEI: Don't allow ghes_ack_error() to mask earlier errors ACPI / APEI: Move NOTIFY_SEA between the estatus-queue and NOTIFY_NMI ACPI / APEI: Switch NOTIFY_SEA to use the estatus queue KVM: arm/arm64: Add kvm_ras.h to collect kvm specific RAS plumbing arm64: KVM/mm: Move SEA handling behind a single 'claim' interface ACPI / APEI: Move locking to the notification helper ACPI / APEI: Let the notification helper specify the fixmap slot ACPI / APEI: Pass ghes and estatus separately to avoid a later copy ACPI / APEI: Make GHES estatus header validation more user friendly ACPI / APEI: Split ghes_read_estatus() to allow a peek at the CPER length ACPI / APEI: Only use queued estatus entry during in_nmi_queue_one_entry() ACPI / APEI: Use separate fixmap pages for arm64 NMI-like notifications mm/memory-failure: Add memory_failure_queue_kick() ACPI / APEI: Kick the memory_failure() queue for synchronous errors arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work firmware: arm_sdei: Add ACPI GHES registration helper ACPI / APEI: Add support for the SDEI GHES Notification type arch/arm/include/asm/kvm_ras.h | 14 + arch/arm/include/asm/system_misc.h | 5 - arch/arm64/include/asm/acpi.h | 4 +- arch/arm64/include/asm/daifflags.h | 1 + arch/arm64/include/asm/fixmap.h | 6 +- arch/arm64/include/asm/kvm_ras.h | 25 + arch/arm64/include/asm/system_misc.h | 2 - arch/arm64/kernel/acpi.c | 54 ++ arch/arm64/mm/fault.c | 25 +- drivers/acpi/apei/Kconfig | 12 +- drivers/acpi/apei/ghes.c | 725 ++++++++++++++++----------- drivers/acpi/apei/hest.c | 10 +- drivers/firmware/arm_sdei.c | 68 +++ include/acpi/ghes.h | 7 +- include/linux/arm_sdei.h | 9 + include/linux/mm.h | 1 + mm/memory-failure.c | 15 +- virt/kvm/arm/mmu.c | 4 +- 18 files changed, 646 insertions(+), 341 deletions(-) create mode 100644 arch/arm/include/asm/kvm_ras.h create mode 100644 arch/arm64/include/asm/kvm_ras.h -- 2.20.1
