- 09 Dec, 2020 1 commit
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Catalin Marinas authored
Merge branches 'for-next/kvm-build-fix', 'for-next/va-refactor', 'for-next/lto', 'for-next/mem-hotplug', 'for-next/cppc-ffh', 'for-next/pad-image-header', 'for-next/zone-dma-default-32-bit', 'for-next/signal-tag-bits' and 'for-next/cmdline-extended' into for-next/core * for-next/kvm-build-fix: : Fix KVM build issues with 64K pages KVM: arm64: Fix build error in user_mem_abort() * for-next/va-refactor: : VA layout changes arm64: mm: don't assume struct page is always 64 bytes Documentation/arm64: fix RST layout of memory.rst arm64: mm: tidy up top of kernel VA space arm64: mm: make vmemmap region a projection of the linear region arm64: mm: extend linear region for 52-bit VA configurations * for-next/lto: : Upgrade READ_ONCE() to RCpc acquire on arm64 with LTO arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y arm64: alternatives: Remove READ_ONCE() usage during patch operation arm64: cpufeatures: Add capability for LDAPR instruction arm64: alternatives: Split up alternative.h arm64: uaccess: move uao_* alternatives to asm-uaccess.h * for-next/mem-hotplug: : Memory hotplug improvements arm64/mm/hotplug: Ensure early memory sections are all online arm64/mm/hotplug: Enable MEM_OFFLINE event handling arm64/mm/hotplug: Register boot memory hot remove notifier earlier arm64: mm: account for hotplug memory when randomizing the linear region * for-next/cppc-ffh: : Add CPPC FFH support using arm64 AMU counters arm64: abort counter_read_on_cpu() when irqs_disabled() arm64: implement CPPC FFH support using AMUs arm64: split counter validation function arm64: wrap and generalise counter read functions * for-next/pad-image-header: : Pad Image header to 64KB and unmap it arm64: head: tidy up the Image header definition arm64/head: avoid symbol names pointing into first 64 KB of kernel image arm64: omit [_text, _stext) from permanent kernel mapping * for-next/zone-dma-default-32-bit: : Default to 32-bit wide ZONE_DMA (previously reduced to 1GB for RPi4) of: unittest: Fix build on architectures without CONFIG_OF_ADDRESS mm: Remove examples from enum zone_type comment arm64: mm: Set ZONE_DMA size based on early IORT scan arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges of: unittest: Add test for of_dma_get_max_cpu_address() of/address: Introduce of_dma_get_max_cpu_address() arm64: mm: Move zone_dma_bits initialization into zone_sizes_init() arm64: mm: Move reserve_crashkernel() into mem_init() arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is required arm64: Ignore any DMA offsets in the max_zone_phys() calculation * for-next/signal-tag-bits: : Expose the FAR_EL1 tag bits in siginfo arm64: expose FAR_EL1 tag bits in siginfo signal: define the SA_EXPOSE_TAGBITS bit in sa_flags signal: define the SA_UNSUPPORTED bit in sa_flags arch: provide better documentation for the arch-specific SA_* flags signal: clear non-uapi flag bits when passing/returning sa_flags arch: move SA_* definitions to generic headers parisc: start using signal-defs.h parisc: Drop parisc special case for __sighandler_t * for-next/cmdline-extended: : Add support for CONFIG_CMDLINE_EXTENDED arm64: Extend the kernel command line from the bootloader arm64: kaslr: Refactor early init command line parsing
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- 02 Dec, 2020 1 commit
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Catalin Marinas authored
of_dma_get_max_cpu_address() is not defined if !CONFIG_OF_ADDRESS, so return early in of_unittest_dma_get_max_cpu_address(). Fixes: 07d13a1d ("of: unittest: Add test for of_dma_get_max_cpu_address()") Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
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- 27 Nov, 2020 2 commits
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Tyler Hicks authored
Provide support for additional kernel command line parameters to be concatenated onto the end of the command line provided by the bootloader. Additional parameters are specified in the CONFIG_CMDLINE option when CONFIG_CMDLINE_EXTEND is selected, matching other architectures and leveraging existing support in the FDT and EFI stub code. Special care must be taken for the arch-specific nokaslr parsing. Search the bootargs FDT property and the CONFIG_CMDLINE when CONFIG_CMDLINE_EXTEND is in use. There are a couple of known use cases for this feature: 1) Switching between stable and development kernel versions, where one of the versions benefits from additional command line parameters, such as debugging options. 2) Specifying additional command line parameters, for additional tuning or debugging, when the bootloader does not offer an interactive mode. Signed-off-by:
Tyler Hicks <tyhicks@linux.microsoft.com> Link: https://lore.kernel.org/r/20200921191557.350256-3-tyhicks@linux.microsoft.comSigned-off-by:
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Tyler Hicks authored
Don't ask for *the* command line string to search for "nokaslr" in kaslr_early_init(). Instead, tell a helper function to search all the appropriate command line strings for "nokaslr" and return the result. This paves the way for searching multiple command line strings without having to concatenate the strings in early init. Signed-off-by:
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- 23 Nov, 2020 8 commits
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Peter Collingbourne authored
The kernel currently clears the tag bits (i.e. bits 56-63) in the fault address exposed via siginfo.si_addr and sigcontext.fault_address. However, the tag bits may be needed by tools in order to accurately diagnose memory errors, such as HWASan [1] or future tools based on the Memory Tagging Extension (MTE). Expose these bits via the arch_untagged_si_addr mechanism, so that they are only exposed to signal handlers with the SA_EXPOSE_TAGBITS flag set. [1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.htmlSigned-off-by:
Peter Collingbourne <pcc@google.com> Reviewed-by:
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Peter Collingbourne authored
Architectures that support address tagging, such as arm64, may want to expose fault address tag bits to the signal handler to help diagnose memory errors. However, these bits have not been previously set, and their presence may confuse unaware user applications. Therefore, introduce a SA_EXPOSE_TAGBITS flag bit in sa_flags that a signal handler may use to explicitly request that the bits are set. The generic signal handler APIs expect to receive tagged addresses. Architectures may specify how to untag addresses in the case where SA_EXPOSE_TAGBITS is clear by defining the arch_untagged_si_addr function. Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com> Link: https://linux-review.googlesource.com/id/I16dd0ed2081f091fce97be0190cb8caa874c26cb Link: https://lkml.kernel.org/r/13cf24d00ebdd8e1f55caf1821c7c29d54100191.1605904350.git.pcc@google.comSigned-off-by:
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Peter Collingbourne authored
Define a sa_flags bit, SA_UNSUPPORTED, which will never be supported in the uapi. The purpose of this flag bit is to allow userspace to distinguish an old kernel that does not clear unknown sa_flags bits from a kernel that supports every flag bit. In other words, if userspace does something like: act.sa_flags |= SA_UNSUPPORTED; sigaction(SIGSEGV, &act, 0); sigaction(SIGSEGV, 0, &oldact); and finds that SA_UNSUPPORTED remains set in oldact.sa_flags, it means that the kernel cannot be trusted to have cleared unknown flag bits from sa_flags, so no assumptions about flag bit support can be made. Signed-off-by:
Dave Martin <Dave.Martin@arm.com> Link: https://linux-review.googlesource.com/id/Ic2501ad150a3a79c1cf27fb8c99be342e9dffbcb Link: https://lkml.kernel.org/r/bda7ddff8895a9bc4ffc5f3cf3d4d37a32118077.1605582887.git.pcc@google.comSigned-off-by:
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Peter Collingbourne authored
Instead of documenting the arch-specific flag values in a comment at the top where they may be easily overlooked, document them in comments inline with the definitions in numerical order so that it is clear why specific values must be chosen for new generic flags and to reduce the likelihood of conflicts between generic and arch-specific flags. Signed-off-by:
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Peter Collingbourne authored
Previously we were not clearing non-uapi flag bits in sigaction.sa_flags when storing the userspace-provided sa_flags or when returning them via oldact. Start doing so. This allows userspace to detect missing support for flag bits and allows the kernel to use non-uapi bits internally, as we are already doing in arch/x86 for two flag bits. Now that this change is in place, we no longer need the code in arch/x86 that was hiding these bits from userspace, so remove it. This is technically a userspace-visible behavior change for sigaction, as the unknown bits returned via oldact.sa_flags are no longer set. However, we are free to define the behavior for unknown bits exactly because their behavior is currently undefined, so for now we can define the meaning of each of them to be "clear the bit in oldact.sa_flags unless the bit becomes known in the future". Furthermore, this behavior is consistent with OpenBSD [1], illumos [2] and XNU [3] (FreeBSD [4] and NetBSD [5] fail the syscall if unknown bits are set). So there is some precedent for this behavior in other kernels, and in particular in XNU, which is probably the most popular kernel among those that I looked at, which means that this change is less likely to be a compatibility issue. Link: [1] https://github.com/openbsd/src/blob/f634a6a4b5bf832e9c1de77f7894ae2625e74484/sys/kern/kern_sig.c#L278 Link: [2] https://github.com/illumos/illumos-gate/blob/76f19f5fdc974fe5be5c82a556e43a4df93f1de1/usr/src/uts/common/syscall/sigaction.c#L86 Link: [3] https://github.com/apple/darwin-xnu/blob/a449c6a3b8014d9406c2ddbdc81795da24aa7443/bsd/kern/kern_sig.c#L480 Link: [4] https://github.com/freebsd/freebsd/blob/eded70c37057857c6e23fae51f86b8f8f43cd2d0/sys/kern/kern_sig.c#L699 Link: [5] https://github.com/NetBSD/src/blob/3365779becdcedfca206091a645a0e8e22b2946e/sys/kern/sys_sig.c#L473Signed-off-by:
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Peter Collingbourne authored
Most architectures with the exception of alpha, mips, parisc and sparc use the same values for these flags. Move their definitions into asm-generic/signal-defs.h and allow the architectures with non-standard values to override them. Also, document the non-standard flag values in order to make it easier to add new generic flags in the future. A consequence of this change is that on powerpc and x86, the constants' values aside from SA_RESETHAND change signedness from unsigned to signed. This is not expected to impact realistic use of these constants. In particular the typical use of the constants where they are or'ed together and assigned to sa_flags (or another int variable) would not be affected. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Acked-by:
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Peter Collingbourne authored
We currently include signal-defs.h on all architectures except parisc. Make parisc fall in line. This will make maintenance easier once the flag bits are moved here. Signed-off-by:
Helge Deller <deller@gmx.de> Acked-by:
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Helge Deller authored
I believe we can and *should* drop this parisc-specific typedef for __sighandler_t when compiling a 64-bit kernel. The reasons: 1. We don't have a 64-bit userspace yet, so nothing (on userspace side) can break. 2. Inside the Linux kernel, this is only used in kernel/signal.c, in function kernel_sigaction() where the signal handler is compared against SIG_IGN. SIG_IGN is defined as (__sighandler_t)1), so only the pointers are compared. 3. Even when a 64-bit userspace gets added at some point, I think __sighandler_t should be defined what it is: a function pointer struct. I compiled kernel/signal.c with and without the patch, and the produced code is identical in both cases. Signed-off-by:
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- 20 Nov, 2020 8 commits
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Nicolas Saenz Julienne authored
We can't really list every setup in common code. On top of that they are unlikely to stay true for long as things change in the arch trees independently of this comment. Suggested-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by:
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Ard Biesheuvel authored
We recently introduced a 1 GB sized ZONE_DMA to cater for platforms incorporating masters that can address less than 32 bits of DMA, in particular the Raspberry Pi 4, which has 4 or 8 GB of DRAM, but has peripherals that can only address up to 1 GB (and its PCIe host bridge can only access the bottom 3 GB) Instructing the DMA layer about these limitations is straight-forward, even though we had to fix some issues regarding memory limits set in the IORT for named components, and regarding the handling of ACPI _DMA methods. However, the DMA layer also needs to be able to allocate memory that is guaranteed to meet those DMA constraints, for bounce buffering as well as allocating the backing for consistent mappings. This is why the 1 GB ZONE_DMA was introduced recently. Unfortunately, it turns out the having a 1 GB ZONE_DMA as well as a ZONE_DMA32 causes problems with kdump, and potentially in other places where allocations cannot cross zone boundaries. Therefore, we should avoid having two separate DMA zones when possible. So let's do an early scan of the IORT, and only create the ZONE_DMA if we encounter any devices that need it. This puts the burden on the firmware to describe such limitations in the IORT, which may be redundant (and less precise) if _DMA methods are also being provided. However, it should be noted that this situation is highly unusual for arm64 ACPI machines. Also, the DMA subsystem still gives precedence to the _DMA method if implemented, and so we will not lose the ability to perform streaming DMA outside the ZONE_DMA if the _DMA method permits it. [nsaenz: unified implementation with DT's counterpart] Signed-off-by:
Ard Biesheuvel <ardb@kernel.org> Signed-off-by:
Jeremy Linton <jeremy.linton@arm.com> Acked-by:
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by:
Hanjun Guo <guohanjun@huawei.com> Cc: Jeremy Linton <jeremy.linton@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20201119175400.9995-7-nsaenzjulienne@suse.deSigned-off-by:
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Nicolas Saenz Julienne authored
We recently introduced a 1 GB sized ZONE_DMA to cater for platforms incorporating masters that can address less than 32 bits of DMA, in particular the Raspberry Pi 4, which has 4 or 8 GB of DRAM, but has peripherals that can only address up to 1 GB (and its PCIe host bridge can only access the bottom 3 GB) The DMA layer also needs to be able to allocate memory that is guaranteed to meet those DMA constraints, for bounce buffering as well as allocating the backing for consistent mappings. This is why the 1 GB ZONE_DMA was introduced recently. Unfortunately, it turns out the having a 1 GB ZONE_DMA as well as a ZONE_DMA32 causes problems with kdump, and potentially in other places where allocations cannot cross zone boundaries. Therefore, we should avoid having two separate DMA zones when possible. So, with the help of of_dma_get_max_cpu_address() get the topmost physical address accessible to all DMA masters in system and use that information to fine-tune ZONE_DMA's size. In the absence of addressing limited masters ZONE_DMA will span the whole 32-bit address space, otherwise, in the case of the Raspberry Pi 4 it'll only span the 30-bit address space, and have ZONE_DMA32 cover the rest of the 32-bit address space. Signed-off-by:
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Nicolas Saenz Julienne authored
Introduce a test for of_dma_get_max_cup_address(), it uses the same DT data as the rest of dma-ranges unit tests. Signed-off-by:
Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20201119175400.9995-5-nsaenzjulienne@suse.deSigned-off-by:
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Nicolas Saenz Julienne authored
Introduce of_dma_get_max_cpu_address(), which provides the highest CPU physical address addressable by all DMA masters in the system. It's specially useful for setting memory zones sizes at early boot time. Signed-off-by:
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Nicolas Saenz Julienne authored
zone_dma_bits's initialization happens earlier that it's actually needed, in arm64_memblock_init(). So move it into the more suitable zone_sizes_init(). Signed-off-by:
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Nicolas Saenz Julienne authored
crashkernel might reserve memory located in ZONE_DMA. We plan to delay ZONE_DMA's initialization after unflattening the devicetree and ACPI's boot table initialization, so move it later in the boot process. Specifically into bootmem_init() since request_standard_resources() depends on it. Signed-off-by:
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Catalin Marinas authored
mem_init() currently relies on knowing the boundaries of the crashkernel reservation to map such region with page granularity for later unmapping via set_memory_valid(..., 0). If the crashkernel reservation is deferred, such boundaries are not known when the linear mapping is created. Simply parse the command line for "crashkernel" and, if found, create the linear map with NO_BLOCK_MAPPINGS. Signed-off-by:
James Morse <james.morse@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Link: https://lore.kernel.org/r/20201119175556.18681-1-catalin.marinas@arm.comSigned-off-by:
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- 19 Nov, 2020 1 commit
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Catalin Marinas authored
Currently, the kernel assumes that if RAM starts above 32-bit (or zone_bits), there is still a ZONE_DMA/DMA32 at the bottom of the RAM and such constrained devices have a hardwired DMA offset. In practice, we haven't noticed any such hardware so let's assume that we can expand ZONE_DMA32 to the available memory if no RAM below 4GB. Similarly, ZONE_DMA is expanded to the 4GB limit if no RAM addressable by zone_bits. Signed-off-by:
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- 17 Nov, 2020 3 commits
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Ard Biesheuvel authored
Even though support for EFI boot remains entirely optional for arm64, it is unlikely that we will ever be able to repurpose the image header fields that the EFI loader relies on, i.e., the magic NOP at offset 0x0 and the PE header address at offset 0x3c. So let's factor out the differences into a 'efi_signature_nop' macro and a local symbol representing the PE header address, and move the conditional definitions into efi-header.S, taking into account whether CONFIG_EFI is enabled or not. While at it, switch to a signature NOP that behaves more like a NOP, i.e., one that only clobbers the flags. Signed-off-by:
Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201117124729.12642-4-ardb@kernel.orgSigned-off-by:
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Ard Biesheuvel authored
We no longer map the first 64 KB of the kernel image, as there is nothing there that we ever need to refer back to once the kernel has booted. Even though facilities like kallsyms are very careful to only refer to the region that starts at _stext when mapping virtual addresses to symbol names, let's avoid any confusion by switching to local .L prefixed symbol names for the EFI header, as none of them have any significance to the rest of the kernel. Signed-off-by:
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Ard Biesheuvel authored
In a previous patch, we increased the size of the EFI PE/COFF header to 64 KB, which resulted in the _stext symbol to appear at a fixed offset of 64 KB into the image. Since 64 KB is also the largest page size we support, this completely removes the need to map the first 64 KB of the kernel image, given that it only contains the arm64 Image header and the EFI header, neither of which we ever access again after booting the kernel. More importantly, we should avoid an executable mapping of non-executable and not entirely predictable data, to deal with the unlikely event that we inadvertently emitted something that looks like an opcode that could be used as a gadget for speculative execution. So let's limit the kernel mapping of .text to the [_stext, _etext) region, which matches the view of generic code (such as kallsyms) when it reasons about the boundaries of the kernel's .text section. Signed-off-by:
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- 13 Nov, 2020 4 commits
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Ionela Voinescu authored
Given that smp_call_function_single() can deadlock when interrupts are disabled, abort the SMP call if irqs_disabled(). This scenario is currently not possible given the function's uses, but safeguard this for potential future uses. Signed-off-by:
Ionela Voinescu <ionela.voinescu@arm.com> Cc: Will Deacon <will@kernel.org> Acked-by:
Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20201113155328.4194-1-ionela.voinescu@arm.com [catalin.marinas@arm.com: modified following Mark's comment] Signed-off-by:
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Ionela Voinescu authored
If Activity Monitors (AMUs) are present, two of the counters can be used to implement support for CPPC's (Collaborative Processor Performance Control) delivered and reference performance monitoring functionality using FFH (Functional Fixed Hardware). Given that counters for a certain CPU can only be read from that CPU, while FFH operations can be called from any CPU for any of the CPUs, use smp_call_function_single() to provide the requested values. Therefore, depending on the register addresses, the following values are returned: - 0x0 (DeliveredPerformanceCounterRegister): AMU core counter - 0x1 (ReferencePerformanceCounterRegister): AMU constant counter The use of Activity Monitors is hidden behind the generic cpu_read_{corecnt,constcnt}() functions. Read functionality for these two registers represents the only current FFH support for CPPC. Read operations for other register values or write operation for all registers are unsupported. Therefore, keep CPPC's FFH unsupported if no CPUs have valid AMU frequency counters. For this purpose, the get_cpu_with_amu_feat() is introduced. Signed-off-by:Sudeep Holla <sudeep.holla@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201106125334.21570-4-ionela.voinescu@arm.comSigned-off-by:
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Ionela Voinescu authored
In order for the counter validation function to be reused, split validate_cpu_freq_invariance_counters() into: - freq_counters_valid(cpu) - check cpu for valid cycle counters - freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) - generic function that sets the normalization ratio used by topology_scale_freq_tick() Signed-off-by:
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Ionela Voinescu authored
In preparation for other uses of Activity Monitors (AMU) cycle counters, place counter read functionality in generic functions that can reused: read_corecnt() and read_constcnt(). As a result, implement update_freq_counters_refs() to replace init_cpu_freq_invariance_counters() and both initialise and update the per-cpu reference variables. Signed-off-by:
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- 12 Nov, 2020 1 commit
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Ard Biesheuvel authored
Commit 8c96400d simplified the page-to-virt and virt-to-page conversions, based on the assumption that struct page is always 64 bytes in size, in which case we can use a single signed shift to perform the conversion (provided that the vmemmap array is placed appropriately in the kernel VA space) Unfortunately, this assumption turns out not to hold, and so we need to revert part of this commit, and go back to an affine transformation. Given that all the quantities involved are compile time constants, this should not make any practical difference. Fixes: 8c96400d ("arm64: mm: make vmemmap region a projection of the linear region") Reported-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
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- 10 Nov, 2020 5 commits
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Anshuman Khandual authored
This adds a validation function that scans the entire boot memory and makes sure that all early memory sections are online. This check is essential for the memory notifier to work properly, as it cannot prevent any boot memory from offlining, if all sections are not online to begin with. Although the boot section scanning is selectively enabled with DEBUG_VM. Signed-off-by:
Anshuman Khandual <anshuman.khandual@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Steve Capper <steve.capper@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/1604896137-16644-4-git-send-email-anshuman.khandual@arm.comSigned-off-by:
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Anshuman Khandual authored
This enables MEM_OFFLINE memory event handling. It will help intercept any possible error condition such as if boot memory some how still got offlined even after an explicit notifier failure, potentially by a future change in generic hot plug framework. This would help detect such scenarios and help debug further. While here, also call out the first section being attempted for offline or got offlined. Signed-off-by:
Gavin Shan <gshan@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Steve Capper <steve.capper@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/1604896137-16644-3-git-send-email-anshuman.khandual@arm.comSigned-off-by:
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Anshuman Khandual authored
This moves memory notifier registration earlier in the boot process from device_initcall() to early_initcall() which will help in guarding against potential early boot memory offline requests. Even though there should not be any actual offlinig requests till memory block devices are initialized with memory_dev_init() but then generic init sequence might just change in future. Hence an early registration for the memory event notifier would be helpful. While here, just skip the registration if CONFIG_MEMORY_HOTREMOVE is not enabled and also call out when memory notifier registration fails. Signed-off-by:
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Ard Biesheuvel authored
As a hardening measure, we currently randomize the placement of physical memory inside the linear region when KASLR is in effect. Since the random offset at which to place the available physical memory inside the linear region is chosen early at boot, it is based on the memblock description of memory, which does not cover hotplug memory. The consequence of this is that the randomization offset may be chosen such that any hotplugged memory located above memblock_end_of_DRAM() that appears later is pushed off the end of the linear region, where it cannot be accessed. So let's limit this randomization of the linear region to ensure that this can no longer happen, by using the CPU's addressable PA range instead. As it is guaranteed that no hotpluggable memory will appear that falls outside of that range, we can safely put this PA range sized window anywhere in the linear region. Signed-off-by:
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Ard Biesheuvel authored
Stephen reports that commit f4693c27 ("arm64: mm: extend linear region for 52-bit VA configurations") triggers the following warnings when building the htmldocs make target of today's linux-next: Documentation/arm64/memory.rst:35: WARNING: Literal block ends without a blank line; unexpected unindent. Documentation/arm64/memory.rst:53: WARNING: Literal block ends without a blank line; unexpected unindent. Let's tweak the memory layout table to work around this. Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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- 09 Nov, 2020 6 commits
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Will Deacon authored
When building with LTO, there is an increased risk of the compiler converting an address dependency headed by a READ_ONCE() invocation into a control dependency and consequently allowing for harmful reordering by the CPU. Ensure that such transformations are harmless by overriding the generic READ_ONCE() definition with one that provides acquire semantics when building with LTO. Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
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Will Deacon authored
In preparation for patching the internals of READ_ONCE() itself, replace its usage on the alternatives patching patch with a volatile variable instead. Acked-by:
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Will Deacon authored
Armv8.3 introduced the LDAPR instruction, which provides weaker memory ordering semantics than LDARi (RCpc vs RCsc). Generally, we provide an RCsc implementation when implementing the Linux memory model, but LDAPR can be used as a useful alternative to dependency ordering, particularly when the compiler is capable of breaking the dependencies. Since LDAPR is not available on all CPUs, add a cpufeature to detect it at runtime and allow the instruction to be used with alternative code patching. Acked-by:
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Will Deacon authored
asm/alternative.h contains both the macros needed to use alternatives, as well the type definitions and function prototypes for applying them. Split the header in two, so that alternatives can be used from core header files such as linux/compiler.h without the risk of circular includes Acked-by:
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Mark Rutland authored
The uao_* alternative asm macros are only used by the uaccess assembly routines in arch/arm64/lib/, where they are included indirectly via asm-uaccess.h. Since they're specific to the uaccess assembly (and will lose the alternatives in subsequent patches), let's move them into asm-uaccess.h. There should be no functional change as a result of this patch. Signed-off-by:
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Ard Biesheuvel authored
Tidy up the way the top of the kernel VA space is organized, by mirroring the 256 MB region we have below the vmalloc space, and populating it top down with the PCI I/O space, some guard regions, and the fixmap region. The latter region is itself populated top down, and today only covers about 4 MB, and so 224 MB is ample, and no guard region is therefore required. The resulting layout is identical between 48-bit/4k and 52-bit/64k configurations. Signed-off-by:
Steve Capper <steve.capper@arm.com> Link: https://lore.kernel.org/r/20201008153602.9467-5-ardb@kernel.orgSigned-off-by:
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