kernel/linux.git/arch/arm64/include, branch v5.16

Merge tag 'efi-urgent-for-v5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

2021-12-27T16:58:35+00:00

Pull EFI fix from Ard Biesheuvel: "Another EFI fix for v5.16: - Prevent missing prototype warning from breaking the build under CONFIG_WERROR=y" * tag 'efi-urgent-for-v5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: efi: Move efifb_setup_from_dmi() prototype from arch headers

efi: Move efifb_setup_from_dmi() prototype from arch headers

2021-12-13T14:07:16+00:00

Commit 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches") made the Generic System Framebuffers (sysfb) driver able to be built on non-x86 architectures. But it left the efifb_setup_from_dmi() function prototype declaration in the architecture specific headers. This could lead to the following compiler warning as reported by the kernel test robot: drivers/firmware/efi/sysfb_efi.c:70:6: warning: no previous prototype for function 'efifb_setup_from_dmi' [-Wmissing-prototypes] void efifb_setup_from_dmi(struct screen_info *si, const char *opt) ^ drivers/firmware/efi/sysfb_efi.c:70:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void efifb_setup_from_dmi(struct screen_info *si, const char *opt) Fixes: 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches") Reported-by: kernel test robot Cc: # 5.15.x Signed-off-by: Javier Martinez Canillas Acked-by: Thomas Zimmermann Link: https://lore.kernel.org/r/20211126001333.555514-1-javierm@redhat.com Signed-off-by: Ard Biesheuvel

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

2021-11-30T17:22:15+00:00

Pull kvm fixes from Paolo Bonzini: "ARM64: - Fix constant sign extension affecting TCR_EL2 and preventing running on ARMv8.7 models due to spurious bits being set - Fix use of helpers using PSTATE early on exit by always sampling it as soon as the exit takes place - Move pkvm's 32bit handling into a common helper RISC-V: - Fix incorrect KVM_MAX_VCPUS value - Unmap stage2 mapping when deleting/moving a memslot x86: - Fix and downgrade BUG_ON due to uninitialized cache - Many APICv and MOVE_ENC_CONTEXT_FROM fixes - Correctly emulate TLB flushes around nested vmentry/vmexit and when the nested hypervisor uses VPID - Prevent modifications to CPUID after the VM has run - Other smaller bugfixes Generic: - Memslot handling bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits) KVM: fix avic_set_running for preemptable kernels KVM: VMX: clear vmx_x86_ops.sync_pir_to_irr if APICv is disabled KVM: SEV: accept signals in sev_lock_two_vms KVM: SEV: do not take kvm->lock when destroying KVM: SEV: Prohibit migration of a VM that has mirrors KVM: SEV: Do COPY_ENC_CONTEXT_FROM with both VMs locked selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM KVM: SEV: move mirror status to destination of KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM KVM: SEV: initialize regions_list of a mirror VM KVM: SEV: cleanup locking for KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM KVM: SEV: do not use list_replace_init on an empty list KVM: x86: Use a stable condition around all VT-d PI paths KVM: x86: check PIR even for vCPUs with disabled APICv KVM: VMX: prepare sync_pir_to_irr for running with APICv disabled KVM: selftests: page_table_test: fix calculation of guest_test_phys_mem KVM: x86/mmu: Handle "default" period when selectively waking kthread KVM: MMU: shadow nested paging does not have PKU KVM: x86/mmu: Remove spurious TLB flushes in TDP MMU zap collapsible path KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU notifier unmapping KVM: X86: Use vcpu->arch.walk_mmu for kvm_mmu_invlpg() ...

KVM: arm64: Avoid setting the upper 32 bits of TCR_EL2 and CPTR_EL2 to 1

2021-11-25T15:51:25+00:00

Having a signed (1 << 31) constant for TCR_EL2_RES1 and CPTR_EL2_TCPAC causes the upper 32-bit to be set to 1 when assigning them to a 64-bit variable. Bit 32 in TCR_EL2 is no longer RES0 in ARMv8.7: with FEAT_LPA2 it changes the meaning of bits 49:48 and 9:8 in the stage 1 EL2 page table entries. As a result of the sign-extension, a non-VHE kernel can no longer boot on a model with ARMv8.7 enabled. CPTR_EL2 still has the top 32 bits RES0 but we should preempt any future problems Make these top bit constants unsigned as per commit df655b75c43f ("arm64: KVM: Avoid setting the upper 32 bits of VTCR_EL2 to 1"). Signed-off-by: Catalin Marinas Reported-by: Chris January Cc: Cc: Will Deacon Cc: Marc Zyngier Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20211125152014.2806582-1-catalin.marinas@arm.com

arm64: uaccess: avoid blocking within critical sections

2021-11-24T09:16:26+00:00

As Vincent reports in: https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com The put_user() in schedule_tail() can get stuck in a livelock, similar to a problem recently fixed on riscv in commit: 285a76bb2cf51b0c ("riscv: evaluate put_user() arg before enabling user access") In __raw_put_user() we have a critical section between uaccess_ttbr0_enable() and uaccess_ttbr0_disable() where we cannot safely call into the scheduler without having taken an exception, as schedule() and other scheduling functions will not save/restore the TTBR0 state. If either of the `x` or `ptr` arguments to __raw_put_user() contain a blocking call, we may call into the scheduler within the critical section. This can result in two problems: 1) The access within the critical section will occur without the required TTBR0 tables installed. This will fault, and where the required tables permit access, the access will be retried without the required tables, resulting in a livelock. 2) When TTBR0 SW PAN is in use, check_and_switch_context() does not modify TTBR0, leaving a stale value installed. The mappings of the blocked task will erroneously be accessible to regular accesses in the context of the new task. Additionally, if the tables are subsequently freed, local TLB maintenance required to reuse the ASID may be lost, potentially resulting in TLB corruption (e.g. in the presence of CnP). The same issue exists for __raw_get_user() in the critical section between uaccess_ttbr0_enable() and uaccess_ttbr0_disable(). A similar issue exists for __get_kernel_nofault() and __put_kernel_nofault() for the critical section between __uaccess_enable_tco_async() and __uaccess_disable_tco_async(), as the TCO state is not context-switched by direct calls into the scheduler. Here the TCO state may be lost from the context of the current task, resulting in unexpected asynchronous tag check faults. It may also be leaked to another task, suppressing expected tag check faults. To fix all of these cases, we must ensure that we do not directly call into the scheduler in their respective critical sections. This patch reworks __raw_put_user(), __raw_get_user(), __get_kernel_nofault(), and __put_kernel_nofault(), ensuring that parameters are evaluated outside of the critical sections. To make this requirement clear, comments are added describing the problem, and line spaces added to separate the critical sections from other portions of the macros. For __raw_get_user() and __raw_put_user() the `err` parameter is conditionally assigned to, and we must currently evaluate this in the critical section. This behaviour is relied upon by the signal code, which uses chains of put_user_error() and get_user_error(), checking the return value at the end. In all cases, the `err` parameter is a plain int rather than a more complex expression with a blocking call, so this is safe. In future we should try to clean up the `err` usage to remove the potential for this to be a problem. Aside from the changes to time of evaluation, there should be no functional change as a result of this patch. Reported-by: Vincent Whitchurch Link: https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com Fixes: f253d827f33c ("arm64: uaccess: refactor __{get,put}_user") Signed-off-by: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Link: https://lore.kernel.org/r/20211122125820.55286-1-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: mm: Fix VM_BUG_ON(mm != &init_mm) for trans_pgd

2021-11-16T10:12:57+00:00

trans_pgd_create_copy() can hit "VM_BUG_ON(mm != &init_mm)" in the function pmd_populate_kernel(). This is the combined consequence of commit 5de59884ac0e ("arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions"), which replaced &init_mm with NULL and commit 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings"), which introduced the VM_BUG_ON. Since the former sounds reasonable, it is better to work on the later. From the perspective of trans_pgd, two groups of functions are considered in the later one: pmd_populate_kernel() mm == NULL should be fixed, else it hits VM_BUG_ON() p?d_populate() mm == NULL means PXN, that is OK, since trans_pgd only copies a linear map, no execution will happen on the map. So it is good enough to just relax VM_BUG_ON() to disregard mm == NULL Fixes: 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings") Signed-off-by: Pingfan Liu Cc: # 5.13.x Cc: Ard Biesheuvel Cc: James Morse Cc: Matthias Brugger Reviewed-by: Catalin Marinas Reviewed-by: Pasha Tatashin Link: https://lore.kernel.org/r/20211112052214.9086-1-kernelfans@gmail.com Signed-off-by: Will Deacon

arm64: ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR

2021-11-16T09:47:54+00:00

When CONFIG_FUNCTION_GRAPH_TRACER is selected and the function graph tracer is in use, unwind_frame() may erroneously associate a traced function with an incorrect return address. This can happen when starting an unwind from a pt_regs, or when unwinding across an exception boundary. This can be seen when recording with perf while the function graph tracer is in use. For example: | # echo function_graph > /sys/kernel/debug/tracing/current_tracer | # perf record -g -e raw_syscalls:sys_enter:k /bin/true | # perf report ... reports the callchain erroneously as: | el0t_64_sync | el0t_64_sync_handler | el0_svc_common.constprop.0 | perf_callchain | get_perf_callchain | syscall_trace_enter | syscall_trace_enter ... whereas when the function graph tracer is not in use, it reports: | el0t_64_sync | el0t_64_sync_handler | el0_svc | do_el0_svc | el0_svc_common.constprop.0 | syscall_trace_enter | syscall_trace_enter The underlying problem is that ftrace_graph_get_ret_stack() takes an index offset from the most recent entry added to the fgraph return stack. We start an unwind at offset 0, and increment the offset each time we encounter a rewritten return address (i.e. when we see `return_to_handler`). This is broken in two cases: 1) Between creating a pt_regs and starting the unwind, function calls may place entries on the stack, leaving an arbitrary offset which we can only determine by performing a full unwind from the caller of the unwind code (and relying on none of the unwind code being instrumented). This can result in erroneous entries being reported in a backtrace recorded by perf or kfence when the function graph tracer is in use. Currently show_regs() is unaffected as dump_backtrace() performs an initial unwind. 2) When unwinding across an exception boundary (whether continuing an unwind or starting a new unwind from regs), we currently always skip the LR of the interrupted context. Where this was live and contained a rewritten address, we won't consume the corresponding fgraph ret stack entry, leaving subsequent entries off-by-one. This can result in erroneous entries being reported in a backtrace performed by any in-kernel unwinder when that backtrace crosses an exception boundary, with entries after the boundary being reported incorrectly. This includes perf, kfence, show_regs(), panic(), etc. To fix this, we need to be able to uniquely identify each rewritten return address such that we can map this back to the original return address. We can use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR to associate each rewritten return address with a unique location on the stack. As the return address is passed in the LR (and so is not guaranteed a unique location in memory), we use the FP upon entry to the function (i.e. the address of the caller's frame record) as the return address pointer. Any nested call will have a different FP value as the caller must create its own frame record and update FP to point to this. Since ftrace_graph_ret_addr() requires the return address with the PAC stripped, the stripping of the PAC is moved before the fixup of the rewritten address. As we would unconditionally strip the PAC, moving this earlier is not harmful, and we can avoid a redundant strip in the return address fixup code. I've tested this with the perf case above, the ftrace selftests, and a number of ad-hoc unwinder tests. The tests all pass, and I have seen no unexpected behaviour as a result of this change. I've tested with pointer authentication under QEMU TCG where magic-sysrq+l correctly recovers the original return addresses. Note that this doesn't fix the issue of skipping a live LR at an exception boundary, which is a more general problem and requires more substantial rework. Were we to consume the LR in all cases this would result in warnings where the interrupted context's LR contains `return_to_handler`, but the FP has been altered, e.g. | func: | <--- ftrace entry ---> // logs FP & LR, rewrites LR | STP FP, LR, [SP, #-16]! | MOV FP, SP | <--- INTERRUPT ---> ... as ftrace_graph_get_ret_stack() fill not find a matching entry, triggering the WARN_ON_ONCE() in unwind_frame(). Link: https://lore.kernel.org/r/20211025164925.GB2001@C02TD0UTHF1T.local Link: https://lore.kernel.org/r/20211027132529.30027-1-mark.rutland@arm.com Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Madhavan T. Venkataraman Cc: Mark Brown Cc: Steven Rostedt Cc: Will Deacon Reviewed-by: Mark Brown Link: https://lore.kernel.org/r/20211029162245.39761-1-mark.rutland@arm.com Signed-off-by: Will Deacon

Merge tag 'kvmarm-fixes-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

2021-11-12T21:01:55+00:00

KVM/arm64 fixes for 5.16, take #1 - Fix the host S2 finalization by solely iterating over the memblocks instead of the whole IPA space - Tighten the return value of kvm_vcpu_preferred_target() now that 32bit support is long gone - Make sure the extraction of ESR_ELx.EC is limited to the architected bits - Comment fixups

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2021-11-10T19:29:30+00:00

Pull arm64 fixes from Will Deacon: - Fix double-evaluation of 'pte' macro argument when using 52-bit PAs - Fix signedness of some MTE prctl PR_* constants - Fix kmemleak memory usage by skipping early pgtable allocations - Fix printing of CPU feature register strings - Remove redundant -nostdlib linker flag for vDSO binaries * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: pgtable: make __pte_to_phys/__phys_to_pte_val inline functions arm64: Track no early_pgtable_alloc() for kmemleak arm64: mte: change PR_MTE_TCF_NONE back into an unsigned long arm64: vdso: remove -nostdlib compiler flag arm64: arm64_ftr_reg->name may not be a human-readable string

Merge tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2021-11-10T19:22:03+00:00

Pull asm-generic cleanup from Arnd Bergmann: "This is a single cleanup from Peter Collingbourne, removing some dead code" * tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: arch: remove unused function syscall_set_arguments()