kernel.git/arch/arm64/include/asm/pgtable-prot.h, branch linux-5.10.y

arm64: mte: Map hotplugged memory as Normal Tagged

2021-03-17T16:06:28Z

commit d15dfd31384ba3cb93150e5f87661a76fa419f74 upstream. In a system supporting MTE, the linear map must allow reading/writing allocation tags by setting the memory type as Normal Tagged. Currently, this is only handled for memory present at boot. Hotplugged memory uses Normal non-Tagged memory. Introduce pgprot_mhp() for hotplugged memory and use it in add_memory_resource(). The arm64 code maps pgprot_mhp() to pgprot_tagged(). Note that ZONE_DEVICE memory should not be mapped as Tagged and therefore setting the memory type in arch_add_memory() is not feasible. Signed-off-by: Catalin Marinas Fixes: 0178dc761368 ("arm64: mte: Use Normal Tagged attributes for the linear map") Reported-by: Patrick Daly Tested-by: Patrick Daly Link: https://lore.kernel.org/r/1614745263-27827-1-git-send-email-pdaly@codeaurora.org Cc: # 5.10.x Cc: Will Deacon Cc: Andrew Morton Cc: Vincenzo Frascino Cc: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Vincenzo Frascino Reviewed-by: Anshuman Khandual Link: https://lore.kernel.org/r/20210309122601.5543-1-catalin.marinas@arm.com Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2020-10-23T18:17:56Z

Pull KVM updates from Paolo Bonzini: "For x86, there is a new alternative and (in the future) more scalable implementation of extended page tables that does not need a reverse map from guest physical addresses to host physical addresses. For now it is disabled by default because it is still lacking a few of the existing MMU's bells and whistles. However it is a very solid piece of work and it is already available for people to hammer on it. Other updates: ARM: - New page table code for both hypervisor and guest stage-2 - Introduction of a new EL2-private host context - Allow EL2 to have its own private per-CPU variables - Support of PMU event filtering - Complete rework of the Spectre mitigation PPC: - Fix for running nested guests with in-kernel IRQ chip - Fix race condition causing occasional host hard lockup - Minor cleanups and bugfixes x86: - allow trapping unknown MSRs to userspace - allow userspace to force #GP on specific MSRs - INVPCID support on AMD - nested AMD cleanup, on demand allocation of nested SVM state - hide PV MSRs and hypercalls for features not enabled in CPUID - new test for MSR_IA32_TSC writes from host and guest - cleanups: MMU, CPUID, shared MSRs - LAPIC latency optimizations ad bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (232 commits) kvm: x86/mmu: NX largepage recovery for TDP MMU kvm: x86/mmu: Don't clear write flooding count for direct roots kvm: x86/mmu: Support MMIO in the TDP MMU kvm: x86/mmu: Support write protection for nesting in tdp MMU kvm: x86/mmu: Support disabling dirty logging for the tdp MMU kvm: x86/mmu: Support dirty logging for the TDP MMU kvm: x86/mmu: Support changed pte notifier in tdp MMU kvm: x86/mmu: Add access tracking for tdp_mmu kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU kvm: x86/mmu: Add TDP MMU PF handler kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg kvm: x86/mmu: Support zapping SPTEs in the TDP MMU KVM: Cache as_id in kvm_memory_slot kvm: x86/mmu: Add functions to handle changed TDP SPTEs kvm: x86/mmu: Allocate and free TDP MMU roots kvm: x86/mmu: Init / Uninit the TDP MMU kvm: x86/mmu: Introduce tdp_iter KVM: mmu: extract spte.h and spte.c KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp ...

Merge branch 'for-next/mte' into for-next/core

2020-10-02T11:16:11Z

Add userspace support for the Memory Tagging Extension introduced by Armv8.5. (Catalin Marinas and others) * for-next/mte: (30 commits) arm64: mte: Fix typo in memory tagging ABI documentation arm64: mte: Add Memory Tagging Extension documentation arm64: mte: Kconfig entry arm64: mte: Save tags when hibernating arm64: mte: Enable swap of tagged pages mm: Add arch hooks for saving/restoring tags fs: Handle intra-page faults in copy_mount_options() arm64: mte: ptrace: Add NT_ARM_TAGGED_ADDR_CTRL regset arm64: mte: ptrace: Add PTRACE_{PEEK,POKE}MTETAGS support arm64: mte: Allow {set,get}_tagged_addr_ctrl() on non-current tasks arm64: mte: Restore the GCR_EL1 register after a suspend arm64: mte: Allow user control of the generated random tags via prctl() arm64: mte: Allow user control of the tag check mode via prctl() mm: Allow arm64 mmap(PROT_MTE) on RAM-based files arm64: mte: Validate the PROT_MTE request via arch_validate_flags() mm: Introduce arch_validate_flags() arm64: mte: Add PROT_MTE support to mmap() and mprotect() mm: Introduce arch_calc_vm_flag_bits() arm64: mte: Tags-aware aware memcmp_pages() implementation arm64: Avoid unnecessary clear_user_page() indirection ...

KVM: arm64: Remove unused page-table code

2020-09-11T14:51:15Z

Now that KVM is using the generic page-table code to manage the guest stage-2 page-tables, we can remove a bunch of unused macros, #defines and static inline functions from the old implementation. Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Reviewed-by: Gavin Shan Cc: Marc Zyngier Cc: Quentin Perret Link: https://lore.kernel.org/r/20200911132529.19844-20-will@kernel.org

KVM: arm64: Use generic allocator for hyp stage-1 page-tables

2020-09-11T14:51:13Z

Now that we have a shiny new page-table allocator, replace the hyp page-table code with calls into the new API. This also allows us to remove the extended idmap code, as we can now simply ensure that the VA size is large enough to map everything we need. Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Cc: Marc Zyngier Cc: Quentin Perret Link: https://lore.kernel.org/r/20200911132529.19844-5-will@kernel.org

arm64/mm: Change THP helpers to comply with generic MM semantics

2020-09-11T13:57:30Z

pmd_present() and pmd_trans_huge() are expected to behave in the following manner during various phases of a given PMD. It is derived from a previous detailed discussion on this topic [1] and present THP documentation [2]. pmd_present(pmd): - Returns true if pmd refers to system RAM with a valid pmd_page(pmd) - Returns false if pmd refers to a migration or swap entry pmd_trans_huge(pmd): - Returns true if pmd refers to system RAM and is a trans huge mapping ------------------------------------------------------------------------- | PMD states | pmd_present | pmd_trans_huge | ------------------------------------------------------------------------- | Mapped | Yes | Yes | ------------------------------------------------------------------------- | Splitting | Yes | Yes | ------------------------------------------------------------------------- | Migration/Swap | No | No | ------------------------------------------------------------------------- The problem: PMD is first invalidated with pmdp_invalidate() before it's splitting. This invalidation clears PMD_SECT_VALID as below. PMD Split -> pmdp_invalidate() -> pmd_mkinvalid -> Clears PMD_SECT_VALID Once PMD_SECT_VALID gets cleared, it results in pmd_present() return false on the PMD entry. It will need another bit apart from PMD_SECT_VALID to re- affirm pmd_present() as true during the THP split process. To comply with above mentioned semantics, pmd_trans_huge() should also check pmd_present() first before testing presence of an actual transparent huge mapping. The solution: Ideally PMD_TYPE_SECT should have been used here instead. But it shares the bit position with PMD_SECT_VALID which is used for THP invalidation. Hence it will not be there for pmd_present() check after pmdp_invalidate(). A new software defined PMD_PRESENT_INVALID (bit 59) can be set on the PMD entry during invalidation which can help pmd_present() return true and in recognizing the fact that it still points to memory. This bit is transient. During the split process it will be overridden by a page table page representing normal pages in place of erstwhile huge page. Other pmdp_invalidate() callers always write a fresh PMD value on the entry overriding this transient PMD_PRESENT_INVALID bit, which makes it safe. [1]: https://lkml.org/lkml/2018/10/17/231 [2]: https://www.kernel.org/doc/Documentation/vm/transhuge.txt Signed-off-by: Anshuman Khandual Reviewed-by: Catalin Marinas Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: Marc Zyngier Cc: Suzuki Poulose Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/1599627183-14453-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Will Deacon

arm64: mte: Use Normal Tagged attributes for the linear map

2020-09-03T16:26:31Z

Once user space is given access to tagged memory, the kernel must be able to clear/save/restore tags visible to the user. This is done via the linear mapping, therefore map it as such. The new MT_NORMAL_TAGGED index for MAIR_EL1 is initially mapped as Normal memory and later changed to Normal Tagged via the cpufeature infrastructure. From a mismatched attribute aliases perspective, the Tagged memory is considered a permission and it won't lead to undefined behaviour. Signed-off-by: Catalin Marinas Cc: Will Deacon Cc: Suzuki K Poulose

KVM: arm64: Fix definition of PAGE_HYP_DEVICE

2020-07-08T20:35:48Z

PAGE_HYP_DEVICE is intended to encode attribute bits for an EL2 stage-1 pte mapping a device. Unfortunately, it includes PROT_DEVICE_nGnRE which encodes attributes for EL1 stage-1 mappings such as UXN and nG, which are RES0 for EL2, and DBM which is meaningless as TCR_EL2.HD is not set. Fix the definition of PAGE_HYP_DEVICE so that it doesn't set RES0 bits at EL2. Acked-by: Marc Zyngier Cc: Marc Zyngier Cc: Catalin Marinas Cc: James Morse Cc: Link: https://lore.kernel.org/r/20200708162546.26176-1-will@kernel.org Signed-off-by: Will Deacon

arm64: bti: Fix support for userspace only BTI

2020-05-12T17:45:17Z

When setting PTE_MAYBE_GP we check system_supports_bti() but this is true for systems where only CONFIG_BTI is set causing us to enable BTI on some kernel text. Add an extra check for the kernel mode option, using an ifdef due to line length. Fixes: c8027285e366 ("arm64: Set GP bit in kernel page tables to enable BTI for the kernel") Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20200512113950.29996-1-broonie@kernel.org Signed-off-by: Will Deacon

arm64: Set GP bit in kernel page tables to enable BTI for the kernel

2020-05-07T16:53:20Z

Now that the kernel is built with BTI annotations enable the feature by setting the GP bit in the stage 1 translation tables. This is done based on the features supported by the boot CPU so that we do not need to rewrite the translation tables. In order to avoid potential issues on big.LITTLE systems when there are a mix of BTI and non-BTI capable CPUs in the system when we have enabled kernel mode BTI we change BTI to be a _STRICT_BOOT_CPU_FEATURE when we have kernel BTI. This will prevent any CPUs that don't support BTI being started if the boot CPU supports BTI rather than simply not using BTI as we do when supporting BTI only in userspace. The main concern is the possibility of BTYPE being preserved by a CPU that does not implement BTI when a thread is migrated to it resulting in an incorrect state which could generate an exception when the thread migrates back to a CPU that does support BTI. If we encounter practical systems which mix BTI and non-BTI CPUs we will need to revisit this implementation. Since we currently do not generate landing pads in the BPF JIT we only map the base kernel text in this way. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20200506195138.22086-5-broonie@kernel.org Signed-off-by: Will Deacon