wireguard-linux/arch/arm64/include/asm/memory.h, branch jd/orphan-parallel

arm64: mm: use single quantity to represent the PA to VA translation

2020-10-15T10:14:57Z

On arm64, the global variable memstart_addr represents the physical address of PAGE_OFFSET, and so physical to virtual translations or vice versa used to come down to simple additions or subtractions involving the values of PAGE_OFFSET and memstart_addr. When support for 52-bit virtual addressing was introduced, we had to deal with PAGE_OFFSET potentially being outside of the region that can be covered by the virtual range (as the 52-bit VA capable build needs to be able to run on systems that are only 48-bit VA capable), and for this reason, another translation was introduced, and recorded in the global variable physvirt_offset. However, if we go back to the original definition of memstart_addr, i.e., the physical address of PAGE_OFFSET, it turns out that there is no need for two separate translations: instead, we can simply subtract the size of the unaddressable VA space from memstart_addr to make the available physical memory appear in the 48-bit addressable VA region. This simplifies things, but also fixes a bug on KASLR builds, which may update memstart_addr later on in arm64_memblock_init(), but fails to update vmemmap and physvirt_offset accordingly. Fixes: 5383cc6efed1 ("arm64: mm: Introduce vabits_actual") Signed-off-by: Ard Biesheuvel Reviewed-by: Steve Capper Link: https://lore.kernel.org/r/20201008153602.9467-2-ardb@kernel.org Signed-off-by: Will Deacon

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 ...

arm64: get rid of TEXT_OFFSET

2020-09-07T14:00:52Z

TEXT_OFFSET serves no purpose, and for this reason, it was redefined as 0x0 in the v5.8 timeframe. Since this does not appear to have caused any issues that require us to revisit that decision, let's get rid of the macro entirely, along with any references to it. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org Signed-off-by: Will Deacon

arm64: mte: Add PROT_MTE support to mmap() and mprotect()

2020-09-04T11:46:07Z

To enable tagging on a memory range, the user must explicitly opt in via a new PROT_MTE flag passed to mmap() or mprotect(). Since this is a new memory type in the AttrIndx field of a pte, simplify the or'ing of these bits over the protection_map[] attributes by making MT_NORMAL index 0. There are two conditions for arch_vm_get_page_prot() to return the MT_NORMAL_TAGGED memory type: (1) the user requested it via PROT_MTE, registered as VM_MTE in the vm_flags, and (2) the vma supports MTE, decided during the mmap() call (only) and registered as VM_MTE_ALLOWED. arch_calc_vm_prot_bits() is responsible for registering the user request as VM_MTE. The newly introduced arch_calc_vm_flag_bits() sets VM_MTE_ALLOWED if the mapping is MAP_ANONYMOUS. An MTE-capable filesystem (RAM-based) may be able to set VM_MTE_ALLOWED during its mmap() file ops call. In addition, update VM_DATA_DEFAULT_FLAGS to allow mprotect(PROT_MTE) on stack or brk area. The Linux mmap() syscall currently ignores unknown PROT_* flags. In the presence of MTE, an mmap(PROT_MTE) on a file which does not support MTE will not report an error and the memory will not be mapped as Normal Tagged. For consistency, mprotect(PROT_MTE) will not report an error either if the memory range does not support MTE. Two subsequent patches in the series will propose tightening of this behaviour. Co-developed-by: Vincenzo Frascino Signed-off-by: Vincenzo Frascino Signed-off-by: Catalin Marinas Cc: 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

Merge branch 'for-next/read-barrier-depends' into for-next/core

2020-07-31T17:09:57Z

* for-next/read-barrier-depends: : Allow architectures to override __READ_ONCE() arm64: Reduce the number of header files pulled into vmlinux.lds.S compiler.h: Move compiletime_assert() macros into compiler_types.h checkpatch: Remove checks relating to [smp_]read_barrier_depends() include/linux: Remove smp_read_barrier_depends() from comments tools/memory-model: Remove smp_read_barrier_depends() from informal doc Documentation/barriers/kokr: Remove references to [smp_]read_barrier_depends() Documentation/barriers: Remove references to [smp_]read_barrier_depends() locking/barriers: Remove definitions for [smp_]read_barrier_depends() alpha: Replace smp_read_barrier_depends() usage with smp_[r]mb() vhost: Remove redundant use of read_barrier_depends() barrier asm/rwonce: Don't pull into 'asm-generic/rwonce.h' asm/rwonce: Remove smp_read_barrier_depends() invocation alpha: Override READ_ONCE() with barriered implementation asm/rwonce: Allow __READ_ONCE to be overridden by the architecture compiler.h: Split {READ,WRITE}_ONCE definitions out into rwonce.h tools: bpf: Use local copy of headers including uapi/linux/filter.h

arm64: Reduce the number of header files pulled into vmlinux.lds.S

2020-07-21T09:50:37Z

Although vmlinux.lds.S smells like an assembly file and is compiled with __ASSEMBLY__ defined, it's actually just fed to the preprocessor to create our linker script. This means that any assembly macros defined by headers that it includes will result in a helpful link error: | aarch64-linux-gnu-ld:./arch/arm64/kernel/vmlinux.lds:1: syntax error In preparation for an arm64-private asm/rwonce.h implementation, which will end up pulling assembly macros into linux/compiler.h, reduce the number of headers we include directly and transitively in vmlinux.lds.S Acked-by: Peter Zijlstra (Intel) Signed-off-by: Will Deacon

arm64/panic: Unify all three existing notifier blocks

2020-07-02T14:44:50Z

Currently there are three different registered panic notifier blocks. This unifies all of them into a single one i.e arm64_panic_block, hence reducing code duplication and required calling sequence during panic. This preserves the existing dump sequence. While here, just use device_initcall() directly instead of __initcall() which has been a legacy alias for the earlier. This replacement is a pure cleanup with no functional implications. Signed-off-by: Anshuman Khandual Acked-by: Mark Rutland Cc: Will Deacon Cc: Steve Capper Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/1593405511-7625-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Catalin Marinas

arm64: remove CONFIG_DEBUG_ALIGN_RODATA feature

2020-04-01T20:44:43Z

When CONFIG_DEBUG_ALIGN_RODATA is enabled, kernel segments mapped with different permissions (r-x for .text, r-- for .rodata, rw- for .data, etc) are rounded up to 2 MiB so they can be mapped more efficiently. In particular, it permits the segments to be mapped using level 2 block entries when using 4k pages, which is expected to result in less TLB pressure. However, the mappings for the bulk of the kernel will use level 2 entries anyway, and the misaligned fringes are organized such that they can take advantage of the contiguous bit, and use far fewer level 3 entries than would be needed otherwise. This makes the value of this feature dubious at best, and since it is not enabled in defconfig or in the distro configs, it does not appear to be in wide use either. So let's just remove it. Signed-off-by: Ard Biesheuvel Acked-by: Mark Rutland Acked-by: Will Deacon Acked-by: Laura Abbott Signed-off-by: Catalin Marinas

arm64/mm: Enable memory hot remove

2020-03-04T15:35:44Z

The arch code for hot-remove must tear down portions of the linear map and vmemmap corresponding to memory being removed. In both cases the page tables mapping these regions must be freed, and when sparse vmemmap is in use the memory backing the vmemmap must also be freed. This patch adds unmap_hotplug_range() and free_empty_tables() helpers which can be used to tear down either region and calls it from vmemmap_free() and ___remove_pgd_mapping(). The free_mapped argument determines whether the backing memory will be freed. It makes two distinct passes over the kernel page table. In the first pass with unmap_hotplug_range() it unmaps, invalidates applicable TLB cache and frees backing memory if required (vmemmap) for each mapped leaf entry. In the second pass with free_empty_tables() it looks for empty page table sections whose page table page can be unmapped, TLB invalidated and freed. While freeing intermediate level page table pages bail out if any of its entries are still valid. This can happen for partially filled kernel page table either from a previously attempted failed memory hot add or while removing an address range which does not span the entire page table page range. The vmemmap region may share levels of table with the vmalloc region. There can be conflicts between hot remove freeing page table pages with a concurrent vmalloc() walking the kernel page table. This conflict can not just be solved by taking the init_mm ptl because of existing locking scheme in vmalloc(). So free_empty_tables() implements a floor and ceiling method which is borrowed from user page table tear with free_pgd_range() which skips freeing page table pages if intermediate address range is not aligned or maximum floor-ceiling might not own the entire page table page. Boot memory on arm64 cannot be removed. Hence this registers a new memory hotplug notifier which prevents boot memory offlining and it's removal. While here update arch_add_memory() to handle __add_pages() failures by just unmapping recently added kernel linear mapping. Now enable memory hot remove on arm64 platforms by default with ARCH_ENABLE_MEMORY_HOTREMOVE. This implementation is overall inspired from kernel page table tear down procedure on X86 architecture and user page table tear down method. [Mike and Catalin added P4D page table level support] Reviewed-by: Catalin Marinas Signed-off-by: Mike Rapoport Signed-off-by: Catalin Marinas Signed-off-by: Anshuman Khandual Signed-off-by: Catalin Marinas