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2022-11-15arm64: allow kprobes on EL0 handlersMark Rutland1-2/+2
Currently do_sysinstr() and do_cp15instr() are marked with NOKPROBE_SYMBOL(). However, these are only called for exceptions taken from EL0, and there is no risk of recursion in kprobes, so this is not necessary. Remove the NOKPROBE_SYMBOL() annotation, and rename the two functions to more clearly indicate that these are solely for exceptions taken from EL0, better matching the names used by the lower level entry points in entry-common.c. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: James Morse <[email protected]> Cc: Joey Gouly <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Will Deacon <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-15arm64: insn: always inline hint generationMark Rutland1-2/+12
All users of aarch64_insn_gen_hint() (e.g. aarch64_insn_gen_nop()) pass a constant argument and generate a constant value. Some of those users are noinstr code (e.g. for alternatives patching). For noinstr code it is necessary to either inline these functions or to ensure the out-of-line versions are noinstr. Since in all cases these are generating a constant, make them __always_inline. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Joey Gouly <[email protected]> Cc: Will Deacon <[email protected]> Reviewed-by: Joey Gouly <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-15arm64: insn: simplify insn group identificationMark Rutland1-25/+17
The only code which needs to check for an entire instruction group is the aarch64_insn_is_steppable() helper function used by kprobes, which must not be instrumented, and only needs to check for the "Branch, exception generation and system instructions" class. Currently we have an out-of-line helper in insn.c which must be marked as __kprobes, which indexes a table with some bits extracted from the instruction. In aarch64_insn_is_steppable() we then need to compare the result with an expected enum value. It would be simpler to have a predicate for this, as with the other aarch64_insn_is_*() helpers, which would be always inlined to prevent inadvertent instrumentation, and would permit better code generation. This patch adds a predicate function for this instruction group using the existing __AARCH64_INSN_FUNCS() helpers, and removes the existing out-of-line helper. As the only class we currently care about is the branch+exception+sys class, I have only added helpers for this, and left the other classes unimplemented for now. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Joey Gouly <[email protected]> Cc: Will Deacon <[email protected]> Reviewed-by: Joey Gouly <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-15arm64: insn: always inline predicatesMark Rutland1-16/+80
We have a number of aarch64_insn_*() predicates which are used in code which is not instrumentation safe (e.g. alternatives patching, kprobes). Some of those are marked with __kprobes, but most are not, and are implemented out-of-line in insn.c. This patch moves the predicates to insn.h and marks them with __always_inline. This is ensures that they will respect the instrumentation requirements of their caller which they will be inlined into. At the same time, I've formatted each of the functions consistently as a list, to make them easier to read and update in future. Other than preventing unwanted instrumentation, there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Joey Gouly <[email protected]> Cc: Will Deacon <[email protected]> Reviewed-by: Joey Gouly <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-15arm64: insn: remove aarch64_insn_gen_prefetch()Mark Rutland1-4/+0
There are no users of aarch64_insn_gen_prefetch(), and which encodes a PRFM (immediate) with a hard-coded offset of 0. Remove it for now; we can always restore it with tests if we need it in future. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Joey Gouly <[email protected]> Cc: Will Deacon <[email protected]> Reviewed-by: Joey Gouly <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-15arm64: make is_ttbrX_addr() noinstr-safeMark Rutland1-2/+2
We use is_ttbr0_addr() in noinstr code, but as it's only marked as inline, it's theoretically possible for the compiler to place it out-of-line and instrument it, which would be problematic. Mark is_ttbr0_addr() as __always_inline such that that can safely be used from noinstr code. For consistency, do the same to is_ttbr1_addr(). Note that while is_ttbr1_addr() calls arch_kasan_reset_tag(), this is a macro (and its callees are either macros or __always_inline), so there is not a risk of transient instrumentation. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-14arm64/signal: Document our convention for choosing magic numbersMark Brown1-0/+4
Szabolcs Nagy has pointed out that most of our signal frame magic numbers are chosen to be meaningful ASCII when dumped to aid manual parsing. This seems sensible since it might help someone parsing things out, let's document it so people implementing new signal contexts are aware of it and are more likely to follow it. Signed-off-by: Mark Brown <[email protected]> Link: https://lore.kernel.org/r/[email protected] [will: Fixed typo and tweaked wording] Signed-off-by: Will Deacon <[email protected]>
2022-11-14arm64: atomics: lse: remove stale dependency on JUMP_LABELMark Rutland1-1/+0
Currently CONFIG_ARM64_USE_LSE_ATOMICS depends upon CONFIG_JUMP_LABEL, as the inline atomics were indirected with a static branch. However, since commit: 21fb26bfb01ffe0d ("arm64: alternatives: add alternative_has_feature_*()") ... we use an alternative_branch (which is always available) rather than a static branch, and hence the dependency is unnecessary. Remove the stale dependency, along with the stale include. This will allow the use of LSE atomics in kernels built with CONFIG_JUMP_LABEL=n, and reduces the risk of circular header dependencies via <asm/lse.h>. Signed-off-by: Mark Rutland <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-11Merge tag 'arm64-fixes' of ↵Linus Torvalds2-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes from Catalin Marinas: - Another fix for rodata=full. Since rodata= is not a simple boolean on arm64 (accepting 'full' as well), it got inadvertently broken by changes in the core code. If rodata=on is the default and rodata=off is passed on the kernel command line, rodata_full is never disabled - Fix gcc compiler warning of shifting 0xc0 into bits 31:24 without an explicit conversion to u32 (triggered by the AMPERE1 MIDR definition) - Include asm/ptrace.h in asm/syscall_wrapper.h to fix an incomplete struct pt_regs type causing the BPF verifier to refuse to load a tracing program which accesses pt_regs * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64/syscall: Include asm/ptrace.h in syscall_wrapper header. arm64: Fix bit-shifting UB in the MIDR_CPU_MODEL() macro arm64: fix rodata=full again
2022-11-11KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2Will Deacon1-0/+2
Sharing 'kvm_arm_vmid_bits' between EL1 and EL2 allows the host to modify the variable arbitrarily, potentially leading to all sorts of shenanians as this is used to configure the VTTBR register for the guest stage-2. In preparation for unmapping host sections entirely from EL2, maintain a copy of 'kvm_arm_vmid_bits' in the pKVM hypervisor and initialise it from the host value while it is still trusted. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the hostQuentin Perret1-2/+2
When pKVM is enabled, the hypervisor at EL2 does not trust the host at EL1 and must therefore prevent it from having unrestricted access to internal hypervisor state. The 'kvm_arm_hyp_percpu_base' array holds the offsets for hypervisor per-cpu allocations, so move this this into the nVHE code where it cannot be modified by the untrusted host at EL1. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Return guest memory from EL2 via dedicated teardown memcacheQuentin Perret1-6/+1
Rather than relying on the host to free the previously-donated pKVM hypervisor VM pages explicitly on teardown, introduce a dedicated teardown memcache which allows the host to reclaim guest memory resources without having to keep track of all of the allocations made by the pKVM hypervisor at EL2. Tested-by: Vincent Donnefort <[email protected]> Co-developed-by: Fuad Tabba <[email protected]> Signed-off-by: Fuad Tabba <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> [maz: dropped __maybe_unused from unmap_donated_memory_noclear()] Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Consolidate stage-2 initialisation into a single functionQuentin Perret3-4/+2
The initialisation of guest stage-2 page-tables is currently split across two functions: kvm_init_stage2_mmu() and kvm_arm_setup_stage2(). That is presumably for historical reasons as kvm_arm_setup_stage2() originates from the (now defunct) KVM port for 32-bit Arm. Simplify this code path by merging both functions into one, taking care to map the 'struct kvm' into the hypervisor stage-1 early on in order to simplify the failure path. Tested-by: Vincent Donnefort <[email protected]> Co-developed-by: Fuad Tabba <[email protected]> Signed-off-by: Fuad Tabba <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Add generic hyp_memcache helpersQuentin Perret1-0/+57
The host at EL1 and the pKVM hypervisor at EL2 will soon need to exchange memory pages dynamically for creating and destroying VM state. Indeed, the hypervisor will rely on the host to donate memory pages it can use to create guest stage-2 page-tables and to store VM and vCPU metadata. In order to ease this process, introduce a 'struct hyp_memcache' which is essentially a linked list of available pages, indexed by physical addresses so that it can be passed meaningfully between the different virtual address spaces configured at EL1 and EL2. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Provide I-cache invalidation by virtual address at EL2Will Deacon1-0/+1
In preparation for handling cache maintenance of guest pages from within the pKVM hypervisor at EL2, introduce an EL2 copy of icache_inval_pou() which will later be plumbed into the stage-2 page-table cache maintenance callbacks, ensuring that the initial contents of pages mapped as executable into the guest stage-2 page-table is visible to the instruction fetcher. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Add per-cpu fixmap infrastructure at EL2Quentin Perret1-0/+14
Mapping pages in a guest page-table from within the pKVM hypervisor at EL2 may require cache maintenance to ensure that the initialised page contents is visible even to non-cacheable (e.g. MMU-off) accesses from the guest. In preparation for performing this maintenance at EL2, introduce a per-vCPU fixmap which allows the pKVM hypervisor to map guest pages temporarily into its stage-1 page-table for the purposes of cache maintenance and, in future, poisoning on the reclaim path. The use of a fixmap avoids the need for memory allocation or locking on the map() path. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Co-developed-by: Will Deacon <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1Fuad Tabba2-2/+16
With the pKVM hypervisor at EL2 now offering hypercalls to the host for creating and destroying VM and vCPU structures, plumb these in to the existing arm64 KVM backend to ensure that the hypervisor data structures are allocated and initialised on first vCPU run for a pKVM guest. In the host, 'struct kvm_protected_vm' is introduced to hold the handle of the pKVM VM instance as well as to track references to the memory donated to the hypervisor so that it can be freed back to the host allocator following VM teardown. The stage-2 page-table, hypervisor VM and vCPU structures are allocated separately so as to avoid the need for a large physically-contiguous allocation in the host at run-time. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Fuad Tabba <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Add infrastructure to create and track pKVM instances at EL2Fuad Tabba4-0/+27
Introduce a global table (and lock) to track pKVM instances at EL2, and provide hypercalls that can be used by the untrusted host to create and destroy pKVM VMs and their vCPUs. pKVM VM/vCPU state is directly accessible only by the trusted hypervisor (EL2). Each pKVM VM is directly associated with an untrusted host KVM instance, and is referenced by the host using an opaque handle. Future patches will provide hypercalls to allow the host to initialize/set/get pKVM VM/vCPU state using the opaque handle. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Fuad Tabba <[email protected]> Co-developed-by: Will Deacon <[email protected]> Signed-off-by: Will Deacon <[email protected]> [maz: silence warning on unmap_donated_memory_noclear()] Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-11KVM: arm64: Back the hypervisor 'struct hyp_page' array for all memoryQuentin Perret1-0/+26
The EL2 'vmemmap' array in nVHE Protected mode is currently very sparse: only memory pages owned by the hypervisor itself have a matching 'struct hyp_page'. However, as the size of this struct has been reduced significantly since its introduction, it appears that we can now afford to back the vmemmap for all of memory. Having an easily accessible 'struct hyp_page' for every physical page in memory provides the hypervisor with a simple mechanism to store metadata (e.g. a refcount) that wouldn't otherwise fit in the very limited number of software bits available in the host stage-2 page-table entries. This will be used in subsequent patches when pinning host memory pages for use by the hypervisor at EL2. Tested-by: Vincent Donnefort <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Fix PAR_TO_HPFAR() to work independently of PA_BITS.Ryan Roberts1-1/+5
Kernel configs with PAGE_SIZE=64KB and PA_BITS=48 still advertise 52 bit IPA space on HW that implements LPA. This is by design (admitedly this is a very unlikely configuration in the real world). However on such a config, attempting to create a vm with the guest kernel placed above 48 bits in IPA space results in misbehaviour due to the hypervisor incorrectly interpretting a faulting IPA. Fix up PAR_TO_HPFAR() to always take 52 bits out of the PAR rather than masking to CONFIG_ARM64_PA_BITS. If the system has a smaller implemented PARange this should be safe because the bits are res0. A more robust approach would be to discover the IPA size in use by the page-table and mask based on that, to avoid relying on res0 reading back as zero. But this information is difficult to access safely from the code's location, so take the easy way out. Fixes: bc1d7de8c550 ("kvm: arm64: Add 52bit support for PAR to HPFAR conversoin") Signed-off-by: Ryan Roberts <[email protected]> [maz: commit message fixes] Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Handle stage-2 faults in parallelOliver Upton1-1/+2
The stage-2 map walker has been made parallel-aware, and as such can be called while only holding the read side of the MMU lock. Rip out the conditional locking in user_mem_abort() and instead grab the read lock. Continue to take the write lock from other callsites to kvm_pgtable_stage2_map(). Signed-off-by: Oliver Upton <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Protect stage-2 traversal with RCUOliver Upton1-0/+49
Use RCU to safely walk the stage-2 page tables in parallel. Acquire and release the RCU read lock when traversing the page tables. Defer the freeing of table memory to an RCU callback. Indirect the calls into RCU and provide stubs for hypervisor code, as RCU is not available in such a context. The RCU protection doesn't amount to much at the moment, as readers are already protected by the read-write lock (all walkers that free table memory take the write lock). Nonetheless, a subsequent change will futher relax the locking requirements around the stage-2 MMU, thereby depending on RCU. Signed-off-by: Oliver Upton <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Tear down unlinked stage-2 subtree after break-before-makeOliver Upton1-0/+3
The break-before-make sequence is a bit annoying as it opens a window wherein memory is unmapped from the guest. KVM should replace the PTE as quickly as possible and avoid unnecessary work in between. Presently, the stage-2 map walker tears down a removed table before installing a block mapping when coalescing a table into a block. As the removed table is no longer visible to hardware walkers after the DSB+TLBI, it is possible to move the remaining cleanup to happen after installing the new PTE. Reshuffle the stage-2 map walker to install the new block entry in the pre-order callback. Unwire all of the teardown logic and replace it with a call to kvm_pgtable_stage2_free_removed() after fixing the PTE. The post-order visitor is now completely unnecessary, so drop it. Finally, touch up the comments to better represent the now simplified map walker. Note that the call to tear down the unlinked stage-2 is indirected as a subsequent change will use an RCU callback to trigger tear down. RCU is not available to pKVM, so there is a need to use different implementations on pKVM and non-pKVM VMs. Signed-off-by: Oliver Upton <[email protected]> Reviewed-by: Ben Gardon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Use an opaque type for ptepsOliver Upton1-1/+8
Use an opaque type for pteps and require visitors explicitly dereference the pointer before using. Protecting page table memory with RCU requires that KVM dereferences RCU-annotated pointers before using. However, RCU is not available for use in the nVHE hypervisor and the opaque type can be conditionally annotated with RCU for the stage-2 MMU. Call the type a 'pteref' to avoid a naming collision with raw pteps. No functional change intended. Signed-off-by: Oliver Upton <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Add a helper to tear down unlinked stage-2 subtreesOliver Upton1-0/+11
A subsequent change to KVM will move the tear down of an unlinked stage-2 subtree out of the critical path of the break-before-make sequence. Introduce a new helper for tearing down unlinked stage-2 subtrees. Leverage the existing stage-2 free walkers to do so, with a deep call into __kvm_pgtable_walk() as the subtree is no longer reachable from the root. Signed-off-by: Oliver Upton <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Pass mm_ops through the visitor contextOliver Upton1-0/+1
As a prerequisite for getting visitors off of struct kvm_pgtable, pass mm_ops through the visitor context. No functional change intended. Signed-off-by: Oliver Upton <[email protected]> Reviewed-by: Ben Gardon <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Stash observed pte value in visitor contextOliver Upton1-0/+1
Rather than reading the ptep all over the shop, read the ptep once from __kvm_pgtable_visit() and stick it in the visitor context. Reread the ptep after visiting a leaf in case the callback installed a new table underneath. No functional change intended. Signed-off-by: Oliver Upton <[email protected]> Reviewed-by: Ben Gardon <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Combine visitor arguments into a context structureOliver Upton1-4/+11
Passing new arguments by value to the visitor callbacks is extremely inflexible for stuffing new parameters used by only some of the visitors. Use a context structure instead and pass the pointer through to the visitor callback. While at it, redefine the 'flags' parameter to the visitor to contain the bit indicating the phase of the walk. Pass the entire set of flags through the context structure such that the walker can communicate additional state to the visitor callback. No functional change intended. Signed-off-by: Oliver Upton <[email protected]> Reviewed-by: Ben Gardon <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-10KVM: arm64: Enable ring-based dirty memory trackingGavin Shan1-0/+1
Enable ring-based dirty memory tracking on ARM64: - Enable CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL. - Enable CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP. - Set KVM_DIRTY_LOG_PAGE_OFFSET for the ring buffer's physical page offset. - Add ARM64 specific kvm_arch_allow_write_without_running_vcpu() to keep the site of saving vgic/its tables out of the no-running-vcpu radar. Signed-off-by: Gavin Shan <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2022-11-09arm64/mm: Simplify and document pte_to_phys() for 52 bit addressesAnshuman Khandual3-7/+6
pte_to_phys() assembly definition does multiple bits field transformations to derive physical address, embedded inside a page table entry. Unlike its C counter part i.e __pte_to_phys(), pte_to_phys() is not very apparent. It simplifies these operations via a new macro PTE_ADDR_HIGH_SHIFT indicating how far the pte encoded higher address bits need to be left shifted. While here, this also updates __pte_to_phys() and __phys_to_pte_val(). Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Cc: Mark Brown <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: [email protected] Cc: [email protected] Reviewed-by: Ard Biesheuvel <[email protected]> Suggested-by: Ard Biesheuvel <[email protected]> Signed-off-by: Anshuman Khandual <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09arm64: implement dynamic shadow call stack for ClangArd Biesheuvel1-0/+49
Implement dynamic shadow call stack support on Clang, by parsing the unwind tables at init time to locate all occurrences of PACIASP/AUTIASP instructions, and replacing them with the shadow call stack push and pop instructions, respectively. This is useful because the overhead of the shadow call stack is difficult to justify on hardware that implements pointer authentication (PAC), and given that the PAC instructions are executed as NOPs on hardware that doesn't, we can just replace them without breaking anything. As PACIASP/AUTIASP are guaranteed to be paired with respect to manipulations of the return address, replacing them 1:1 with shadow call stack pushes and pops is guaranteed to result in the desired behavior. Signed-off-by: Ard Biesheuvel <[email protected]> Reviewed-by: Sami Tolvanen <[email protected]> Tested-by: Sami Tolvanen <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09arm64: unwind: add asynchronous unwind tables to kernel and modulesArd Biesheuvel1-0/+8
Enable asynchronous unwind table generation for both the core kernel as well as modules, and emit the resulting .eh_frame sections as init code so we can use the unwind directives for code patching at boot or module load time. This will be used by dynamic shadow call stack support, which will rely on code patching rather than compiler codegen to emit the shadow call stack push and pop instructions. Signed-off-by: Ard Biesheuvel <[email protected]> Reviewed-by: Nick Desaulniers <[email protected]> Reviewed-by: Sami Tolvanen <[email protected]> Tested-by: Sami Tolvanen <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09arm64/hwcap: Add support for SVE 2.1Mark Brown2-0/+2
FEAT_SVE2p1 introduces a number of new SVE instructions. Since there is no new architectural state added kernel support is simply a new hwcap which lets userspace know that the feature is supported. Signed-off-by: Mark Brown <[email protected]> Reviewed-by: Catalin Marinas <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09arm64/hwcap: Add support for FEAT_RPRFMMark Brown2-0/+2
FEAT_RPRFM adds a new range prefetch hint within the existing PRFM space for range prefetch hinting. Add a new hwcap to allow userspace to discover support for the new instruction. Signed-off-by: Mark Brown <[email protected]> Reviewed-by: Catalin Marinas <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09arm64/hwcap: Add support for FEAT_CSSCMark Brown2-0/+2
FEAT_CSSC adds a number of new instructions usable to optimise common short sequences of instructions, add a hwcap indicating that the feature is available and can be used by userspace. Signed-off-by: Mark Brown <[email protected]> Reviewed-by: Catalin Marinas <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-09efi: libstub: Factor out min alignment and preferred kernel load addressArd Biesheuvel1-0/+15
Factor out the expressions that describe the preferred placement of the loaded image as well as the minimum alignment so we can reuse them in the decompressor. Signed-off-by: Ard Biesheuvel <[email protected]>
2022-11-09efi: libstub: Move screen_info handling to common codeArd Biesheuvel1-6/+0
Currently, arm64, RISC-V and LoongArch rely on the fact that struct screen_info can be accessed directly, due to the fact that the EFI stub and the core kernel are part of the same image. This will change after a future patch, so let's ensure that the screen_info handling is able to deal with this, by adopting the arm32 approach of passing it as a configuration table. While at it, switch to ACPI reclaim memory to hold the screen_info data, which is more appropriate for this kind of allocation. Signed-off-by: Ard Biesheuvel <[email protected]>
2022-11-09arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.Kuniyuki Iwashima1-1/+1
Add the same change for ARM64 as done in the commit 9440c4294160 ("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to make sure all syscalls see 'struct pt_regs' definition and resulted BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to actual struct. Without this patch, the BPF verifier refuses to load a tracing prog which accesses pt_regs. bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES With this patch, we can see the correct error, which saves us time in debugging the prog. bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4 bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP Signed-off-by: Kuniyuki Iwashima <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Catalin Marinas <[email protected]>
2022-11-09arm64: Fix bit-shifting UB in the MIDR_CPU_MODEL() macroD Scott Phillips1-1/+1
CONFIG_UBSAN_SHIFT with gcc-5 complains that the shifting of ARM_CPU_IMP_AMPERE (0xC0) into bits [31:24] by MIDR_CPU_MODEL() is undefined behavior. Well, sort of, it actually spells the error as: arch/arm64/kernel/proton-pack.c: In function 'spectre_bhb_loop_affected': arch/arm64/include/asm/cputype.h:44:2: error: initializer element is not constant (((imp) << MIDR_IMPLEMENTOR_SHIFT) | \ ^ This isn't an issue for other Implementor codes, as all the other codes have zero in the top bit and so are representable as a signed int. Cast the implementor code to unsigned in MIDR_CPU_MODEL to remove the undefined behavior. Fixes: 0e5d5ae837c8 ("arm64: Add AMPERE1 to the Spectre-BHB affected list") Reported-by: Geert Uytterhoeven <[email protected]> Signed-off-by: D Scott Phillips <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Catalin Marinas <[email protected]>
2022-11-08mm: remove kern_addr_valid() completelyKefeng Wang1-2/+0
Most architectures (except arm64/x86/sparc) simply return 1 for kern_addr_valid(), which is only used in read_kcore(), and it calls copy_from_kernel_nofault() which could check whether the address is a valid kernel address. So as there is no need for kern_addr_valid(), let's remove it. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kefeng Wang <[email protected]> Acked-by: Geert Uytterhoeven <[email protected]> [m68k] Acked-by: Heiko Carstens <[email protected]> [s390] Acked-by: Christoph Hellwig <[email protected]> Acked-by: Helge Deller <[email protected]> [parisc] Acked-by: Michael Ellerman <[email protected]> [powerpc] Acked-by: Guo Ren <[email protected]> [csky] Acked-by: Catalin Marinas <[email protected]> [arm64] Cc: Alexander Gordeev <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Anton Ivanov <[email protected]> Cc: <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Christian Borntraeger <[email protected]> Cc: Christophe Leroy <[email protected]> Cc: Chris Zankel <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David S. Miller <[email protected]> Cc: Dinh Nguyen <[email protected]> Cc: Greg Ungerer <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Huacai Chen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Ivan Kokshaysky <[email protected]> Cc: James Bottomley <[email protected]> Cc: Johannes Berg <[email protected]> Cc: Jonas Bonn <[email protected]> Cc: Matt Turner <[email protected]> Cc: Max Filippov <[email protected]> Cc: Michal Simek <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Palmer Dabbelt <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Richard Henderson <[email protected]> Cc: Richard Weinberger <[email protected]> Cc: Rich Felker <[email protected]> Cc: Russell King <[email protected]> Cc: Stafford Horne <[email protected]> Cc: Stefan Kristiansson <[email protected]> Cc: Sven Schnelle <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vasily Gorbik <[email protected]> Cc: Vineet Gupta <[email protected]> Cc: Will Deacon <[email protected]> Cc: Xuerui Wang <[email protected]> Cc: Yoshinori Sato <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
2022-11-08arm64: Enable data independent timing (DIT) in the kernelArd Biesheuvel1-4/+8
The ARM architecture revision v8.4 introduces a data independent timing control (DIT) which can be set at any exception level, and instructs the CPU to avoid optimizations that may result in a correlation between the execution time of certain instructions and the value of the data they operate on. The DIT bit is part of PSTATE, and is therefore context switched as usual, given that it becomes part of the saved program state (SPSR) when taking an exception. We have also defined a hwcap for DIT, and so user space can discover already whether or nor DIT is available. This means that, as far as user space is concerned, DIT is wired up and fully functional. In the kernel, however, we never bothered with DIT: we disable at it boot (i.e., INIT_PSTATE_EL1 has DIT cleared) and ignore the fact that we might run with DIT enabled if user space happened to set it. Currently, we have no idea whether or not running privileged code with DIT disabled on a CPU that implements support for it may result in a side channel that exposes privileged data to unprivileged user space processes, so let's be cautious and just enable DIT while running in the kernel if supported by all CPUs. Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Marc Zyngier <[email protected]> Cc: Eric Biggers <[email protected]> Cc: Jason A. Donenfeld <[email protected]> Cc: Kees Cook <[email protected]> Cc: Suzuki K Poulose <[email protected]> Cc: Adam Langley <[email protected]> Link: https://lore.kernel.org/all/[email protected]/ Signed-off-by: Ard Biesheuvel <[email protected]> Acked-by: Mark Rutland <[email protected]> Link: https://lore.kernel.org/r/[email protected] [will: Removed cpu_has_dit() as per Mark's suggestion on the list] Signed-off-by: Will Deacon <[email protected]>
2022-11-08arm64/mm: Drop ARM64_KERNEL_USES_PMD_MAPSAnshuman Khandual1-8/+3
Currently ARM64_KERNEL_USES_PMD_MAPS is an unnecessary abstraction. Kernel mapping at PMD (aka huge page aka block) level, is only applicable with 4K base page, which makes it 2MB aligned, a necessary requirement for linear mapping and physical memory start address. This can be easily achieved by directly checking against base page size itself. This drops off the macro ARM64_KERNE_USES_PMD_MAPS which is redundant. Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Cc: [email protected] Signed-off-by: Anshuman Khandual <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-07arm64/asm: Remove unused enable_da macroMark Brown1-5/+0
We no longer use the enable_da macro, remove it to avoid having to think about maintaining it. Signed-off-by: Mark Brown <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-07arm64: alternative: constify alternative_has_feature_* argumentJisheng Zhang1-2/+2
Inspired by x86 commit 864b435514b2("x86/jump_label: Mark arguments as const to satisfy asm constraints"), constify alternative_has_feature_* argument to satisfy asm constraints. And Steven in [1] also pointed out that "The "i" constraint needs to be a constant." Tested with building a simple external kernel module with "O0". Before the patch, got similar gcc warnings and errors as below: In file included from <command-line>: In function ‘alternative_has_feature_likely’, inlined from ‘system_capabilities_finalized’ at arch/arm64/include/asm/cpufeature.h:440:9, inlined from ‘arm64_preempt_schedule_irq’ at arch/arm64/kernel/entry-common.c:264:6: include/linux/compiler_types.h:285:33: warning: ‘asm’ operand 0 probably does not match constraints 285 | #define asm_volatile_goto(x...) asm goto(x) | ^~~ arch/arm64/include/asm/alternative-macros.h:232:9: note: in expansion of macro ‘asm_volatile_goto’ 232 | asm_volatile_goto( | ^~~~~~~~~~~~~~~~~ include/linux/compiler_types.h:285:33: error: impossible constraint in ‘asm’ 285 | #define asm_volatile_goto(x...) asm goto(x) | ^~~ arch/arm64/include/asm/alternative-macros.h:232:9: note: in expansion of macro ‘asm_volatile_goto’ 232 | asm_volatile_goto( | ^~~~~~~~~~~~~~~~~ After the patch, the simple external test kernel module is built fine with "-O0". [1]https://lore.kernel.org/all/[email protected]/ Signed-off-by: Jisheng Zhang <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-07arm64: jump_label: mark arguments as const to satisfy asm constraintsJisheng Zhang1-4/+4
Inspired by x86 commit 864b435514b2("x86/jump_label: Mark arguments as const to satisfy asm constraints"), mark arch_static_branch()'s and arch_static_branch_jump()'s arguments as const to satisfy asm constraints. And Steven in [1] also pointed out that "The "i" constraint needs to be a constant." Tested with building a simple external kernel module with "O0". [1]https://lore.kernel.org/all/[email protected]/ Signed-off-by: Jisheng Zhang <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2022-11-07ARM: 9255/1: efi/dump UEFI runtime page tables for ARMWang Kefeng1-0/+1
UEFI runtime page tables dump only for ARM64 at present, but ARM support EFI and ARM_PTDUMP_DEBUGFS now. Since ARM could potentially execute with a 1G/3G user/kernel split, choosing 1G as the upper limit for UEFI runtime end, with this, we could enable UEFI runtime page tables on ARM. Acked-by: Ard Biesheuvel <[email protected]> Tested-by: Ard Biesheuvel <[email protected]> Signed-off-by: Kefeng Wang <[email protected]> Signed-off-by: Russell King (Oracle) <[email protected]>
2022-11-04Merge tag 'efi-fixes-for-v6.1-2' of ↵Linus Torvalds1-0/+8
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi Pull EFI fixes from Ard Biesheuvel: - A pair of tweaks to the EFI random seed code so that externally provided version of this config table are handled more robustly - Another fix for the v6.0 EFI variable refactor that turned out to break Apple machines which don't provide QueryVariableInfo() - Add some guard rails to the EFI runtime service call wrapper so we can recover from synchronous exceptions caused by firmware * tag 'efi-fixes-for-v6.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: arm64: efi: Recover from synchronous exceptions occurring in firmware efi: efivars: Fix variable writes with unsupported query_variable_store() efi: random: Use 'ACPI reclaim' memory for random seed efi: random: reduce seed size to 32 bytes efi/tpm: Pass correct address to memblock_reserve
2022-11-03arm64: efi: Recover from synchronous exceptions occurring in firmwareArd Biesheuvel1-0/+8
Unlike x86, which has machinery to deal with page faults that occur during the execution of EFI runtime services, arm64 has nothing like that, and a synchronous exception raised by firmware code brings down the whole system. With more EFI based systems appearing that were not built to run Linux (such as the Windows-on-ARM laptops based on Qualcomm SOCs), as well as the introduction of PRM (platform specific firmware routines that are callable just like EFI runtime services), we are more likely to run into issues of this sort, and it is much more likely that we can identify and work around such issues if they don't bring down the system entirely. Since we already use a EFI runtime services call wrapper in assembler, we can quite easily add some code that captures the execution state at the point where the call is made, allowing us to revert to this state and proceed execution if the call triggered a synchronous exception. Given that the kernel and the firmware don't share any data structures that could end up in an indeterminate state, we can happily continue running, as long as we mark the EFI runtime services as unavailable from that point on. Signed-off-by: Ard Biesheuvel <[email protected]> Acked-by: Catalin Marinas <[email protected]>
2022-10-22Merge tag 'kvmarm-fixes-6.1-1' of ↵Paolo Bonzini2-25/+13
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 6.1, take #1 - Fix for stage-2 invalidation holding the VM MMU lock for too long by limiting the walk to the largest block mapping size - Enable stack protection and branch profiling for VHE - Two selftest fixes
2022-10-14Merge tag 'arm64-fixes' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 fixes from Catalin Marinas: - Cortex-A55 errata workaround (repeat TLBI) - AMPERE1 added to the Spectre-BHB affected list - MTE fix to avoid setting PG_mte_tagged if no tags have been touched on a page - Fixed typo in the SCTLR_EL1.SPINTMASK bit naming (the commit log has other typos) - perf: return value check in ali_drw_pmu_probe(), ALIBABA_UNCORE_DRW_PMU dependency on ACPI * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: Add AMPERE1 to the Spectre-BHB affected list arm64: mte: Avoid setting PG_mte_tagged if no tags cleared or restored MAINTAINERS: rectify file entry in ALIBABA PMU DRIVER drivers/perf: ALIBABA_UNCORE_DRW_PMU should depend on ACPI drivers/perf: fix return value check in ali_drw_pmu_probe() arm64: errata: Add Cortex-A55 to the repeat tlbi list arm64/sysreg: Fix typo in SCTR_EL1.SPINTMASK