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2021-04-08arm64: Add __init section marker to some functionsJisheng Zhang1-2/+2
They are not needed after booting, so mark them as __init to move them to the .init section. Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Reviewed-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20210330135449.4dcffd7f@xhacker.debian Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-08arm64/sve: Rework SVE access trap to convert state in registersMark Brown2-9/+22
When we enable SVE usage in userspace after taking a SVE access trap we need to ensure that the portions of the register state that are not shared with the FPSIMD registers are zeroed. Currently we do this by forcing the FPSIMD registers to be saved to the task struct and converting them there. This is wasteful in the common case where the task state is loaded into the registers and we will immediately return to userspace since we can initialise the SVE state directly in registers instead of accessing multiple copies of the register state in memory. Instead in that common case do the conversion in the registers and update the task metadata so that we can return to userspace without spilling the register state to memory unless there is some other reason to do so. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210312190313.24598-1-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-08arm64: entry: Enable random_kstack_offset supportKees Cook2-0/+21
Allow for a randomized stack offset on a per-syscall basis, with roughly 5 bits of entropy. (And include AAPCS rationale AAPCS thanks to Mark Rutland.) In order to avoid unconditional stack canaries on syscall entry (due to the use of alloca()), also disable stack protector to avoid triggering needless checks and slowing down the entry path. As there is no general way to control stack protector coverage with a function attribute[1], this must be disabled at the compilation unit level. This isn't a problem here, though, since stack protector was not triggered before: examining the resulting syscall.o, there are no changes in canary coverage (none before, none now). [1] a working __attribute__((no_stack_protector)) has been added to GCC and Clang but has not been released in any version yet: https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=346b302d09c1e6db56d9fe69048acb32fbb97845 https://reviews.llvm.org/rG4fbf84c1732fca596ad1d6e96015e19760eb8a9b Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210401232347.2791257-6-keescook@chromium.org
2021-04-07arm64: KVM: Enable access to TRBE support for hostSuzuki K Poulose1-1/+2
For a nvhe host, the EL2 must allow the EL1&0 translation regime for TraceBuffer (MDCR_EL2.E2TB == 0b11). This must be saved/restored over a trip to the guest. Also, before entering the guest, we must flush any trace data if the TRBE was enabled. And we must prohibit the generation of trace while we are in EL1 by clearing the TRFCR_EL1. For vhe, the EL2 must prevent the EL1 access to the Trace Buffer. The MDCR_EL2 bit definitions for TRBE are available here : https://developer.arm.com/documentation/ddi0601/2020-12/AArch64-Registers/ Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210405164307.1720226-8-suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
2021-04-01arm64: perf: Remove redundant initialization in perf_event.cQi Liu1-3/+2
The initialization of value in function armv8pmu_read_hw_counter() and armv8pmu_read_counter() seem redundant, as they are soon updated. So, We can remove them. Signed-off-by: Qi Liu <liuqi115@huawei.com> Link: https://lore.kernel.org/r/1617275801-1980-1-git-send-email-liuqi115@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2021-04-01KVM: arm64: Log source when panicking from nVHE hypAndrew Scull1-2/+1
To aid with debugging, add details of the source of a panic from nVHE hyp. This is done by having nVHE hyp exit to nvhe_hyp_panic_handler() rather than directly to panic(). The handler will then add the extra details for debugging before panicking the kernel. If the panic was due to a BUG(), look up the metadata to log the file and line, if available, otherwise log an address that can be looked up in vmlinux. The hyp offset is also logged to allow other hyp VAs to be converted, similar to how the kernel offset is logged during a panic. __hyp_panic_string is now inlined since it no longer needs to be referenced as a symbol and the message is free to diverge between VHE and nVHE. The following is an example of the logs generated by a BUG in nVHE hyp. [ 46.754840] kvm [307]: nVHE hyp BUG at: arch/arm64/kvm/hyp/nvhe/switch.c:242! [ 46.755357] kvm [307]: Hyp Offset: 0xfffea6c58e1e0000 [ 46.755824] Kernel panic - not syncing: HYP panic: [ 46.755824] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800 [ 46.755824] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000 [ 46.755824] VCPU:0000d93a880d0000 [ 46.756960] CPU: 3 PID: 307 Comm: kvm-vcpu-0 Not tainted 5.12.0-rc3-00005-gc572b99cf65b-dirty #133 [ 46.757459] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 [ 46.758366] Call trace: [ 46.758601] dump_backtrace+0x0/0x1b0 [ 46.758856] show_stack+0x18/0x70 [ 46.759057] dump_stack+0xd0/0x12c [ 46.759236] panic+0x16c/0x334 [ 46.759426] arm64_kernel_unmapped_at_el0+0x0/0x30 [ 46.759661] kvm_arch_vcpu_ioctl_run+0x134/0x750 [ 46.759936] kvm_vcpu_ioctl+0x2f0/0x970 [ 46.760156] __arm64_sys_ioctl+0xa8/0xec [ 46.760379] el0_svc_common.constprop.0+0x60/0x120 [ 46.760627] do_el0_svc+0x24/0x90 [ 46.760766] el0_svc+0x2c/0x54 [ 46.760915] el0_sync_handler+0x1a4/0x1b0 [ 46.761146] el0_sync+0x170/0x180 [ 46.761889] SMP: stopping secondary CPUs [ 46.762786] Kernel Offset: 0x3e1cd2820000 from 0xffff800010000000 [ 46.763142] PHYS_OFFSET: 0xffffa9f680000000 [ 46.763359] CPU features: 0x00240022,61806008 [ 46.763651] Memory Limit: none [ 46.813867] ---[ end Kernel panic - not syncing: HYP panic: [ 46.813867] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800 [ 46.813867] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000 [ 46.813867] VCPU:0000d93a880d0000 ]--- Signed-off-by: Andrew Scull <ascull@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210318143311.839894-6-ascull@google.com
2021-03-30Merge tag 'kvmarm-fixes-5.12-3' of ↵Paolo Bonzini1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.12, take #3 - Fix GICv3 MMIO compatibility probing - Prevent guests from using the ARMv8.4 self-hosted tracing extension
2021-03-29arm64: kaslr: support randomized module area with KASAN_VMALLOCLecopzer Chen2-15/+19
After KASAN_VMALLOC works in arm64, we can randomize module region into vmalloc area now. Test: VMALLOC area ffffffc010000000 fffffffdf0000000 before the patch: module_alloc_base/end ffffffc008b80000 ffffffc010000000 after the patch: module_alloc_base/end ffffffdcf4bed000 ffffffc010000000 And the function that insmod some modules is fine. Suggested-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com> Link: https://lore.kernel.org/r/20210324040522.15548-5-lecopzer.chen@mediatek.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-28arm64: stacktrace: Move start_backtrace() out of the headerMark Brown1-0/+24
Currently start_backtrace() is a static inline function in the header. Since it really shouldn't be sufficiently performance critical that we actually need to have it inlined move it into a C file, this will save anyone else scratching their head about why it is defined in the header. As far as I can see it's only there because it was factored out of the various callers. Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210319174022.33051-1-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-26arm64: Support execute-only permissions with Enhanced PANVladimir Murzin1-0/+12
Enhanced Privileged Access Never (EPAN) allows Privileged Access Never to be used with Execute-only mappings. Absence of such support was a reason for 24cecc377463 ("arm64: Revert support for execute-only user mappings"). Thus now it can be revisited and re-enabled. Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210312173811.58284-2-vladimir.murzin@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-25Merge tag 'arm64-fixes' of ↵Linus Torvalds6-6/+22
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes from Will Deacon: "Minor fixes all over, ranging from typos to tests to errata workarounds: - Fix possible memory hotplug failure with KASLR - Fix FFR value in SVE kselftest - Fix backtraces reported in /proc/$pid/stack - Disable broken CnP implementation on NVIDIA Carmel - Typo fixes and ACPI documentation clarification - Fix some W=1 warnings" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: kernel: disable CNP on Carmel arm64/process.c: fix Wmissing-prototypes build warnings kselftest/arm64: sve: Do not use non-canonical FFR register value arm64: mm: correct the inside linear map range during hotplug check arm64: kdump: update ppos when reading elfcorehdr arm64: cpuinfo: Fix a typo Documentation: arm64/acpi : clarify arm64 support of IBFT arm64: stacktrace: don't trace arch_stack_walk() arm64: csum: cast to the proper type
2021-03-25arm64: entry: remove test_irqs_unmasked macroMark Rutland1-14/+0
We haven't needed the test_irqs_unmasked macro since commit: 105fc3352077bba5 ("arm64: entry: move el1 irq/nmi logic to C") ... and as we convert more of the entry logic to C it is decreasingly likely we'll need it in future, so let's remove the unused macro. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210323181201.18889-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-25KVM: arm64: Drop the CPU_FTR_REG_HYP_COPY infrastructureMarc Zyngier1-13/+0
Now that the read_ctr macro has been specialised for nVHE, the whole CPU_FTR_REG_HYP_COPY infrastrcture looks completely overengineered. Simplify it by populating the two u64 quantities (MMFR0 and 1) that the hypervisor need. Reviewed-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-03-25KVM: arm64: Generate final CTR_EL0 value when running in Protected modeMarc Zyngier1-0/+1
In protected mode, late CPUs are not allowed to boot (enforced by the PSCI relay). We can thus specialise the read_ctr macro to always return a pre-computed, sanitised value. Special care is taken to prevent the use of this custome version outside of the protected mode. Reviewed-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-03-25arm64: kernel: disable CNP on CarmelRich Wiley2-1/+12
On NVIDIA Carmel cores, CNP behaves differently than it does on standard ARM cores. On Carmel, if two cores have CNP enabled and share an L2 TLB entry created by core0 for a specific ASID, a non-shareable TLBI from core1 may still see the shared entry. On standard ARM cores, that TLBI will invalidate the shared entry as well. This causes issues with patchsets that attempt to do local TLBIs based on cpumasks instead of broadcast TLBIs. Avoid these issues by disabling CNP support for NVIDIA Carmel cores. Signed-off-by: Rich Wiley <rwiley@nvidia.com> Link: https://lore.kernel.org/r/20210324002809.30271-1-rwiley@nvidia.com [will: Fix pre-existing whitespace issue] Signed-off-by: Will Deacon <will@kernel.org>
2021-03-25arm64/process.c: fix Wmissing-prototypes build warningsManinder Singh1-0/+2
Fix GCC warnings reported when building with "-Wmissing-prototypes": arch/arm64/kernel/process.c:261:6: warning: no previous prototype for '__show_regs' [-Wmissing-prototypes] 261 | void __show_regs(struct pt_regs *regs) | ^~~~~~~~~~~ arch/arm64/kernel/process.c:307:6: warning: no previous prototype for '__show_regs_alloc_free' [-Wmissing-prototypes] 307 | void __show_regs_alloc_free(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~ arch/arm64/kernel/process.c:365:5: warning: no previous prototype for 'arch_dup_task_struct' [-Wmissing-prototypes] 365 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) | ^~~~~~~~~~~~~~~~~~~~ arch/arm64/kernel/process.c:546:41: warning: no previous prototype for '__switch_to' [-Wmissing-prototypes] 546 | __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, | ^~~~~~~~~~~ arch/arm64/kernel/process.c:710:25: warning: no previous prototype for 'arm64_preempt_schedule_irq' [-Wmissing-prototypes] 710 | asmlinkage void __sched arm64_preempt_schedule_irq(void) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ Link: https://lore.kernel.org/lkml/202103192250.AennsfXM-lkp@intel.com Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Link: https://lore.kernel.org/r/1616568899-986-1-git-send-email-maninder1.s@samsung.com Signed-off-by: Will Deacon <will@kernel.org>
2021-03-24arm64: irq: allow FIQs to be handledMark Rutland2-9/+37
On contemporary platforms we don't use FIQ, and treat any stray FIQ as a fatal event. However, some platforms have an interrupt controller wired to FIQ, and need to handle FIQ as part of regular operation. So that we can support both cases dynamically, this patch updates the FIQ exception handling code to operate the same way as the IRQ handling code, with its own handle_arch_fiq handler. Where a root FIQ handler is not registered, an unexpected FIQ exception will trigger the default FIQ handler, which will panic() as today. Where a root FIQ handler is registered, handling of the FIQ is deferred to that handler. As el0_fiq_invalid_compat is supplanted by el0_fiq, the former is removed. For !CONFIG_COMPAT builds we never expect to take an exception from AArch32 EL0, so we keep the common el0_fiq_invalid handler. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210315115629.57191-7-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: Always keep DAIF.[IF] in syncHector Martin3-6/+9
Apple SoCs (A11 and newer) have some interrupt sources hardwired to the FIQ line. We implement support for this by simply treating IRQs and FIQs the same way in the interrupt vectors. To support these systems, the FIQ mask bit needs to be kept in sync with the IRQ mask bit, so both kinds of exceptions are masked together. No other platforms should be delivering FIQ exceptions right now, and we already unmask FIQ in normal process context, so this should not have an effect on other systems - if spurious FIQs were arriving, they would already panic the kernel. Signed-off-by: Hector Martin <marcan@marcan.st> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210315115629.57191-6-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: entry: factor irq triage logic into macrosMarc Zyngier1-37/+43
In subsequent patches we'll allow an FIQ handler to be registered, and FIQ exceptions will need to be triaged very similarly to IRQ exceptions. So that we can reuse the existing logic, this patch factors the IRQ triage logic out into macros that can be reused for FIQ. The macros are named to follow the elX_foo_handler scheme used by the C exception handlers. For consistency with other top-level exception handlers, the kernel_entry/kernel_exit logic is not moved into the macros. As FIQ will use a different C handler, this handler name is provided as an argument to the macros. There should be no functional change as a result of this patch. Signed-off-by: Marc Zyngier <maz@kernel.org> [Mark: rework macros, commit message, rebase before DAIF rework] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210315115629.57191-5-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: irq: rework root IRQ handler registrationMark Rutland1-4/+8
If we accidentally unmask IRQs before we've registered a root IRQ handler, handle_arch_irq will be NULL, and the IRQ exception handler will branch to a bogus address. To make this easier to debug, this patch initialises handle_arch_irq to a default handler which will panic(), making such problems easier to debug. When we add support for FIQ handlers, we can follow the same approach. When we add support for a root FIQ handler, it's possible to have root IRQ handler without an root FIQ handler, and in theory the inverse is also possible. To permit this, and to keep the IRQ/FIQ registration logic similar, this patch removes the panic in the absence of a root IRQ controller. Instead, set_handle_irq() logs when a handler is registered, which is sufficient for debug purposes. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210315115629.57191-4-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: don't use GENERIC_IRQ_MULTI_HANDLERMarc Zyngier1-0/+11
In subsequent patches we want to allow irqchip drivers to register as FIQ handlers, with a set_handle_fiq() function. To keep the IRQ/FIQ paths similar, we want arm64 to provide both set_handle_irq() and set_handle_fiq(), rather than using GENERIC_IRQ_MULTI_HANDLER for the former. This patch adds an arm64-specific implementation of set_handle_irq(). There should be no functional change as a result of this patch. Signed-off-by: Marc Zyngier <maz@kernel.org> [Mark: use a single handler pointer] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Hector Martin <marcan@marcan.st> Cc: James Morse <james.morse@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210315115629.57191-3-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24KVM: arm64: Hide system instruction access to Trace registersSuzuki K Poulose1-1/+0
Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest, when the trace register accesses are trapped (CPTR_EL2.TTA == 1). So, the guest will get an undefined instruction, if trusts the ID registers and access one of the trace registers. Lets be nice to the guest and hide the feature to avoid unexpected behavior. Even though this can be done at KVM sysreg emulation layer, we do this by removing the TRACEVER from the sanitised feature register field. This is fine as long as the ETM drivers can handle the individual trace units separately, even when there are differences among the CPUs. Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210323120647.454211-2-suzuki.poulose@arm.com
2021-03-24arm64: compat: Poison the compat sigpageWill Deacon1-3/+6
Commit 9c698bff66ab ("ARM: ensure the signal page contains defined contents") poisoned the unused portions of the signal page for 32-bit Arm. Implement the same poisoning for the compat signal page on arm64 rather than using __GFP_ZERO. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210318170738.7756-6-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: compat: Allow signal page to be remappedWill Deacon1-0/+9
For compatability with 32-bit Arm, allow the compat signal page to be remapped via mremap(). Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210318170738.7756-4-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: vdso: Remove redundant calls to flush_dcache_page()Will Deacon1-2/+0
flush_dcache_page() ensures that the 'PG_dcache_clean' flag for its 'page' argument is clear so that cache maintenance will be performed if the page is mapped into userspace with execute permissions. Newly allocated pages have this flag clear, so there is no need to call flush_dcache_page() for the compat vdso or signal pages. Remove the redundant calls. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210318170738.7756-3-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-24arm64: vdso: Use GFP_KERNEL for allocating compat vdso and signal pagesWill Deacon1-2/+2
There's no need to allocate the compat vDSO and signal pages using GFP_ATOMIC allocations, so use GFP_KERNEL instead. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210318170738.7756-2-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-22arm64: kdump: update ppos when reading elfcorehdrPavel Tatashin1-0/+2
The ppos points to a position in the old kernel memory (and in case of arm64 in the crash kernel since elfcorehdr is passed as a segment). The function should update the ppos by the amount that was read. This bug is not exposed by accident, but other platforms update this value properly. So, fix it in ARM64 version of elfcorehdr_read() as well. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> Fixes: e62aaeac426a ("arm64: kdump: provide /proc/vmcore file") Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Link: https://lore.kernel.org/r/20210319205054.743368-1-pasha.tatashin@soleen.com Signed-off-by: Will Deacon <will@kernel.org>
2021-03-22arm64: cpuinfo: Fix a typoBhaskar Chowdhury1-1/+1
s/acurate/accurate/ Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20210319222848.29928-1-unixbhaskar@gmail.com Signed-off-by: Will Deacon <will@kernel.org>
2021-03-22arm64: stacktrace: don't trace arch_stack_walk()Mark Rutland1-4/+5
We recently converted arm64 to use arch_stack_walk() in commit: 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK") The core stacktrace code expects that (when tracing the current task) arch_stack_walk() starts a trace at its caller, and does not include itself in the trace. However, arm64's arch_stack_walk() includes itself, and so traces include one more entry than callers expect. The core stacktrace code which calls arch_stack_walk() tries to skip a number of entries to prevent itself appearing in a trace, and the additional entry prevents skipping one of the core stacktrace functions, leaving this in the trace unexpectedly. We can fix this by having arm64's arch_stack_walk() begin the trace with its caller. The first value returned by the trace will be __builtin_return_address(0), i.e. the caller of arch_stack_walk(). The first frame record to be unwound will be __builtin_frame_address(1), i.e. the caller's frame record. To prevent surprises, arch_stack_walk() is also marked noinline. While __builtin_frame_address(1) is not safe in portable code, local GCC developers have confirmed that it is safe on arm64. To find the caller's frame record, the builtin can safely dereference the current function's frame record or (in theory) could stash the original FP into another GPR at function entry time, neither of which are problematic. Prior to this patch, the tracing code would unexpectedly show up in traces of the current task, e.g. | # cat /proc/self/stack | [<0>] stack_trace_save_tsk+0x98/0x100 | [<0>] proc_pid_stack+0xb4/0x130 | [<0>] proc_single_show+0x60/0x110 | [<0>] seq_read_iter+0x230/0x4d0 | [<0>] seq_read+0xdc/0x130 | [<0>] vfs_read+0xac/0x1e0 | [<0>] ksys_read+0x6c/0xfc | [<0>] __arm64_sys_read+0x20/0x30 | [<0>] el0_svc_common.constprop.0+0x60/0x120 | [<0>] do_el0_svc+0x24/0x90 | [<0>] el0_svc+0x2c/0x54 | [<0>] el0_sync_handler+0x1a4/0x1b0 | [<0>] el0_sync+0x170/0x180 After this patch, the tracing code will not show up in such traces: | # cat /proc/self/stack | [<0>] proc_pid_stack+0xb4/0x130 | [<0>] proc_single_show+0x60/0x110 | [<0>] seq_read_iter+0x230/0x4d0 | [<0>] seq_read+0xdc/0x130 | [<0>] vfs_read+0xac/0x1e0 | [<0>] ksys_read+0x6c/0xfc | [<0>] __arm64_sys_read+0x20/0x30 | [<0>] el0_svc_common.constprop.0+0x60/0x120 | [<0>] do_el0_svc+0x24/0x90 | [<0>] el0_svc+0x2c/0x54 | [<0>] el0_sync_handler+0x1a4/0x1b0 | [<0>] el0_sync+0x170/0x180 Erring on the side of caution, I've given this a spin with a bunch of toolchains, verifying the output of /proc/self/stack and checking that the assembly looked sound. For GCC (where we require version 5.1.0 or later) I tested with the kernel.org crosstool binares for versions 5.5.0, 6.4.0, 6.5.0, 7.3.0, 7.5.0, 8.1.0, 8.3.0, 8.4.0, 9.2.0, and 10.1.0. For clang (where we require version 10.0.1 or later) I tested with the llvm.org binary releases of 11.0.0, and 11.0.1. Fixes: 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Jun <chenjun102@huawei.com> Cc: Marco Elver <elver@google.com> Cc: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: <stable@vger.kernel.org> # 5.10.x Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210319184106.5688-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-03-19KVM: arm64: Page-align the .hyp sectionsQuentin Perret1-13/+9
We will soon unmap the .hyp sections from the host stage 2 in Protected nVHE mode, which obviously works with at least page granularity, so make sure to align them correctly. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-37-qperret@google.com
2021-03-19KVM: arm64: Wrap the host with a stage 2Quentin Perret1-0/+3
When KVM runs in protected nVHE mode, make use of a stage 2 page-table to give the hypervisor some control over the host memory accesses. The host stage 2 is created lazily using large block mappings if possible, and will default to page mappings in absence of a better solution. >From this point on, memory accesses from the host to protected memory regions (e.g. not 'owned' by the host) are fatal and lead to hyp_panic(). Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-36-qperret@google.com
2021-03-19KVM: arm64: Set host stage 2 using kvm_nvhe_init_paramsQuentin Perret1-0/+3
Move the registers relevant to host stage 2 enablement to kvm_nvhe_init_params to prepare the ground for enabling it in later patches. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-22-qperret@google.com
2021-03-19KVM: arm64: Prepare the creation of s1 mappings at EL2Quentin Perret1-0/+16
When memory protection is enabled, the EL2 code needs the ability to create and manage its own page-table. To do so, introduce a new set of hypercalls to bootstrap a memory management system at EL2. This leads to the following boot flow in nVHE Protected mode: 1. the host allocates memory for the hypervisor very early on, using the memblock API; 2. the host creates a set of stage 1 page-table for EL2, installs the EL2 vectors, and issues the __pkvm_init hypercall; 3. during __pkvm_init, the hypervisor re-creates its stage 1 page-table and stores it in the memory pool provided by the host; 4. the hypervisor then extends its stage 1 mappings to include a vmemmap in the EL2 VA space, hence allowing to use the buddy allocator introduced in a previous patch; 5. the hypervisor jumps back in the idmap page, switches from the host-provided page-table to the new one, and wraps up its initialization by enabling the new allocator, before returning to the host. 6. the host can free the now unused page-table created for EL2, and will now need to issue hypercalls to make changes to the EL2 stage 1 mappings instead of modifying them directly. Note that for the sake of simplifying the review, this patch focuses on the hypervisor side of things. In other words, this only implements the new hypercalls, but does not make use of them from the host yet. The host-side changes will follow in a subsequent patch. Credits to Will for __pkvm_init_switch_pgd. Acked-by: Will Deacon <will@kernel.org> Co-authored-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-18-qperret@google.com
2021-03-19KVM: arm64: Enable access to sanitized CPU features at EL2Quentin Perret1-0/+13
Introduce the infrastructure in KVM enabling to copy CPU feature registers into EL2-owned data-structures, to allow reading sanitised values directly at EL2 in nVHE. Given that only a subset of these features are being read by the hypervisor, the ones that need to be copied are to be listed under <asm/kvm_cpufeature.h> together with the name of the nVHE variable that will hold the copy. This introduces only the infrastructure enabling this copy. The first users will follow shortly. Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-14-qperret@google.com
2021-03-19KVM: arm64: Introduce a BSS section for use at HypQuentin Perret1-18/+34
Currently, the hyp code cannot make full use of a bss, as the kernel section is mapped read-only. While this mapping could simply be changed to read-write, it would intermingle even more the hyp and kernel state than they currently are. Instead, introduce a __hyp_bss section, that uses reserved pages, and create the appropriate RW hyp mappings during KVM init. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
2021-03-19KVM: arm64: Link position-independent string routines into .hyp.textWill Deacon1-0/+11
Pull clear_page(), copy_page(), memcpy() and memset() into the nVHE hyp code and ensure that we always execute the '__pi_' entry point on the offchance that it changes in future. [ qperret: Commit title nits and added linker script alias ] Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210319100146.1149909-3-qperret@google.com
2021-03-18arm64: Use INIT_SCTLR_EL1_MMU_OFF to disable the MMU on CPU restartMarc Zyngier1-4/+1
Instead of doing a RMW on SCTLR_EL1 to disable the MMU, use the existing define that loads the right set of bits. Acked-by: Will Deacon <will@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-03-14Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+3
Pull KVM fixes from Paolo Bonzini: "More fixes for ARM and x86" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: LAPIC: Advancing the timer expiration on guest initiated write KVM: x86/mmu: Skip !MMU-present SPTEs when removing SP in exclusive mode KVM: kvmclock: Fix vCPUs > 64 can't be online/hotpluged kvm: x86: annotate RCU pointers KVM: arm64: Fix exclusive limit for IPA size KVM: arm64: Reject VM creation when the default IPA size is unsupported KVM: arm64: Ensure I-cache isolation between vcpus of a same VM KVM: arm64: Don't use cbz/adr with external symbols KVM: arm64: Fix range alignment when walking page tables KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config() KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is available KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key KVM: arm64: Fix nVHE hyp panic host context restore KVM: arm64: Avoid corrupting vCPU context register in guest exit KVM: arm64: nvhe: Save the SPE context early kvm: x86: use NULL instead of using plain integer as pointer KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled' KVM: x86: Ensure deadline timer has truly expired before posting its IRQ
2021-03-11x86/paravirt: Switch time pvops functions to use static_call()Juergen Gross1-4/+9
The time pvops functions are the only ones left which might be used in 32-bit mode and which return a 64-bit value. Switch them to use the static_call() mechanism instead of pvops, as this allows quite some simplification of the pvops implementation. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210311142319.4723-5-jgross@suse.com
2021-03-11arm64: mm: use a 48-bit ID map when possible on 52-bit VA buildsArd Biesheuvel1-1/+1
52-bit VA kernels can run on hardware that is only 48-bit capable, but configure the ID map as 52-bit by default. This was not a problem until recently, because the special T0SZ value for a 52-bit VA space was never programmed into the TCR register anwyay, and because a 52-bit ID map happens to use the same number of translation levels as a 48-bit one. This behavior was changed by commit 1401bef703a4 ("arm64: mm: Always update TCR_EL1 from __cpu_set_tcr_t0sz()"), which causes the unsupported T0SZ value for a 52-bit VA to be programmed into TCR_EL1. While some hardware simply ignores this, Mark reports that Amberwing systems choke on this, resulting in a broken boot. But even before that commit, the unsupported idmap_t0sz value was exposed to KVM and used to program TCR_EL2 incorrectly as well. Given that we already have to deal with address spaces being either 48-bit or 52-bit in size, the cleanest approach seems to be to simply default to a 48-bit VA ID map, and only switch to a 52-bit one if the placement of the kernel in DRAM requires it. This is guaranteed not to happen unless the system is actually 52-bit VA capable. Fixes: 90ec95cda91a ("arm64: mm: Introduce VA_BITS_MIN") Reported-by: Mark Salter <msalter@redhat.com> Link: http://lore.kernel.org/r/20210310003216.410037-1-msalter@redhat.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20210310171515.416643-2-ardb@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2021-03-10arm64: perf: Fix 64-bit event counter read truncationRob Herring1-1/+1
Commit 0fdf1bb75953 ("arm64: perf: Avoid PMXEV* indirection") changed armv8pmu_read_evcntr() to return a u32 instead of u64. The result is silent truncation of the event counter when using 64-bit counters. Given the offending commit appears to have passed thru several folks, it seems likely this was a bad rebase after v8.5 PMU 64-bit counters landed. Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: <stable@vger.kernel.org> Fixes: 0fdf1bb75953 ("arm64: perf: Avoid PMXEV* indirection") Signed-off-by: Rob Herring <robh@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20210310004412.1450128-1-robh@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2021-03-10arm64/mm: Fix __enable_mmu() for new TGRAN range valuesJames Morse1-2/+4
As per ARM ARM DDI 0487G.a, when FEAT_LPA2 is implemented, ID_AA64MMFR0_EL1 might contain a range of values to describe supported translation granules (4K and 16K pages sizes in particular) instead of just enabled or disabled values. This changes __enable_mmu() function to handle complete acceptable range of values (depending on whether the field is signed or unsigned) now represented with ID_AA64MMFR0_TGRAN_SUPPORTED_[MIN..MAX] pair. While here, also fix similar situations in EFI stub and KVM as well. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Cc: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/1615355590-21102-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-03-10arch_topology: Allow multiple entities to provide sched_freq_tick() callbackViresh Kumar1-66/+39
This patch attempts to make it generic enough so other parts of the kernel can also provide their own implementation of scale_freq_tick() callback, which is called by the scheduler periodically to update the per-cpu arch_freq_scale variable. The implementations now need to provide 'struct scale_freq_data' for the CPUs for which they have hardware counters available, and a callback gets registered for each possible CPU in a per-cpu variable. The arch specific (or ARM AMU) counters are updated to adapt to this and they take the highest priority if they are available, i.e. they will be used instead of CPPC based counters for example. The special code to rebuild the sched domains, in case invariance status change for the system, is moved out of arm64 specific code and is added to arch_topology.c. Note that this also defines SCALE_FREQ_SOURCE_CPUFREQ but doesn't use it and it is added to show that cpufreq is also acts as source of information for FIE and will be used by default if no other counters are supported for a platform. Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Tested-by: Ionela Voinescu <ionela.voinescu@arm.com> Acked-by: Will Deacon <will@kernel.org> # for arm64 Tested-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-03-10arch_topology: Rename freq_scale as arch_freq_scaleViresh Kumar1-3/+3
Rename freq_scale to a less generic name, as it will get exported soon for modules. Since x86 already names its own implementation of this as arch_freq_scale, lets stick to that. Suggested-by: Will Deacon <will@kernel.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-03-08arm64: Use common of_kexec_alloc_and_setup_fdt()Rob Herring1-174/+8
The code for setting up the /chosen node in the device tree and updating the memory reservation for the next kernel has been moved to of_kexec_alloc_and_setup_fdt() defined in "drivers/of/kexec.c". Use the common of_kexec_alloc_and_setup_fdt() to setup the device tree and update the memory reservation for kexec for arm64. Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20210221174930.27324-7-nramas@linux.microsoft.com
2021-03-08arm64: Use ELF fields defined in 'struct kimage'Lakshmi Ramasubramanian1-9/+9
ELF related fields elf_headers, elf_headers_sz, and elf_headers_mem have been moved from 'struct kimage_arch' to 'struct kimage' as elf_headers, elf_headers_sz, and elf_load_addr respectively. Use the ELF fields defined in 'struct kimage'. Suggested-by: Rob Herring <robh@kernel.org> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20210221174930.27324-3-nramas@linux.microsoft.com
2021-03-08arm64: Drop support for CMDLINE_EXTENDWill Deacon1-4/+1
The documented behaviour for CMDLINE_EXTEND is that the arguments from the bootloader are appended to the built-in kernel command line. This also matches the option parsing behaviour for the EFI stub and early ID register overrides. Bizarrely, the fdt behaviour is the other way around: appending the built-in command line to the bootloader arguments, resulting in a command-line that doesn't necessarily line-up with the parsing order and definitely doesn't line-up with the documented behaviour. As it turns out, there is a proposal [1] to replace CMDLINE_EXTEND with CMDLINE_PREPEND and CMDLINE_APPEND options which should hopefully make the intended behaviour much clearer. While we wait for those to land, drop CMDLINE_EXTEND for now as there appears to be little enthusiasm for changing the current FDT behaviour. [1] https://lore.kernel.org/lkml/20190319232448.45964-2-danielwa@cisco.com/ Cc: Max Uvarov <muvarov@gmail.com> Cc: Rob Herring <robh@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Doug Anderson <dianders@chromium.org> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: Frank Rowand <frowand.list@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/CAL_JsqJX=TCCs7=gg486r9TN4NYscMTCLNfqJF9crskKPq-bTg@mail.gmail.com Link: https://lore.kernel.org/r/20210303134927.18975-3-will@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2021-03-08arm64: cpufeatures: Fix handling of CONFIG_CMDLINE for idreg overridesWill Deacon1-19/+25
The built-in kernel commandline (CONFIG_CMDLINE) can be configured in three different ways: 1. CMDLINE_FORCE: Use CONFIG_CMDLINE instead of any bootloader args 2. CMDLINE_EXTEND: Append the bootloader args to CONFIG_CMDLINE 3. CMDLINE_FROM_BOOTLOADER: Only use CONFIG_CMDLINE if there aren't any bootloader args. The early cmdline parsing to detect idreg overrides gets (2) and (3) slightly wrong: in the case of (2) the bootloader args are parsed first and in the case of (3) the CMDLINE is always parsed. Fix these issues by moving the bootargs parsing out into a helper function and following the same logic as that used by the EFI stub. Reviewed-by: Marc Zyngier <maz@kernel.org> Fixes: 33200303553d ("arm64: cpufeature: Add an early command-line cpufeature override facility") Link: https://lore.kernel.org/r/20210303134927.18975-2-will@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2021-03-06KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is availableMarc Zyngier1-0/+3
When running under a nesting hypervisor, it isn't guaranteed that the virtual HW will include a PMU. In which case, let's not try to access the PMU registers in the world switch, as that'd be deadly. Reported-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20210209114844.3278746-3-maz@kernel.org Message-Id: <20210305185254.3730990-6-maz@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-27Merge tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+1
Pull io_uring thread rewrite from Jens Axboe: "This converts the io-wq workers to be forked off the tasks in question instead of being kernel threads that assume various bits of the original task identity. This kills > 400 lines of code from io_uring/io-wq, and it's the worst part of the code. We've had several bugs in this area, and the worry is always that we could be missing some pieces for file types doing unusual things (recent /dev/tty example comes to mind, userfaultfd reads installing file descriptors is another fun one... - both of which need special handling, and I bet it's not the last weird oddity we'll find). With these identical workers, we can have full confidence that we're never missing anything. That, in itself, is a huge win. Outside of that, it's also more efficient since we're not wasting space and code on tracking state, or switching between different states. I'm sure we're going to find little things to patch up after this series, but testing has been pretty thorough, from the usual regression suite to production. Any issue that may crop up should be manageable. There's also a nice series of further reductions we can do on top of this, but I wanted to get the meat of it out sooner rather than later. The general worry here isn't that it's fundamentally broken. Most of the little issues we've found over the last week have been related to just changes in how thread startup/exit is done, since that's the main difference between using kthreads and these kinds of threads. In fact, if all goes according to plan, I want to get this into the 5.10 and 5.11 stable branches as well. That said, the changes outside of io_uring/io-wq are: - arch setup, simple one-liner to each arch copy_thread() implementation. - Removal of net and proc restrictions for io_uring, they are no longer needed or useful" * tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits) io-wq: remove now unused IO_WQ_BIT_ERROR io_uring: fix SQPOLL thread handling over exec io-wq: improve manager/worker handling over exec io_uring: ensure SQPOLL startup is triggered before error shutdown io-wq: make buffered file write hashed work map per-ctx io-wq: fix race around io_worker grabbing io-wq: fix races around manager/worker creation and task exit io_uring: ensure io-wq context is always destroyed for tasks arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread() io_uring: cleanup ->user usage io-wq: remove nr_process accounting io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS net: remove cmsg restriction from io_uring based send/recvmsg calls Revert "proc: don't allow async path resolution of /proc/self components" Revert "proc: don't allow async path resolution of /proc/thread-self components" io_uring: move SQPOLL thread io-wq forked worker io-wq: make io_wq_fork_thread() available to other users io-wq: only remove worker from free_list, if it was there io_uring: remove io_identity io_uring: remove any grabbing of context ...