Linear Address Masking[1] (LAM) modifies the checking that is applied to
64-bit linear addresses, allowing software to use of the untranslated
address bits for metadata.
The patchset brings support for LAM for userspace addresses.
LAM_U48 enabling is controversial since it competes for bits with
5-level paging. Its enabling isolated into an optional last patch that
can be applied at maintainer's discretion.
Please review and consider applying.
v5:
- Do not use switch_mm() in enable_lam_func()
- Use mb()/READ_ONCE() pair on LAM enabling;
- Add self-test by Weihong Zhang;
- Add comments;
v4:
- Fix untagged_addr() for LAM_U48;
- Remove no-threads restriction on LAM enabling;
- Fix mm_struct access from /proc/$PID/arch_status
- Fix LAM handling in initialize_tlbstate_and_flush()
- Pack tlb_state better;
- Comments and commit messages;
v3:
- Rebased onto v5.19-rc1
- Per-process enabling;
- API overhaul (again);
- Avoid branches and costly computations in the fast path;
- LAM_U48 is in optional patch.
v2:
- Rebased onto v5.18-rc1
- New arch_prctl(2)-based API
- Expose status of LAM (or other thread features) in
/proc/$PID/arch_status
[1] ISE, Chapter 10. https://cdrdv2.intel.com/v1/dl/getContent/671368
Kirill A. Shutemov (8):
x86/mm: Fix CR3_ADDR_MASK
x86: CPUID and CR3/CR4 flags for Linear Address Masking
mm: Pass down mm_struct to untagged_addr()
x86/mm: Handle LAM on context switch
x86/uaccess: Provide untagged_addr() and remove tags before address
check
x86/mm: Provide ARCH_GET_UNTAG_MASK and ARCH_ENABLE_TAGGED_ADDR
x86: Expose untagging mask in /proc/$PID/arch_status
x86/mm: Extend LAM to support to LAM_U48
Weihong Zhang (5):
selftests/x86/lam: Add malloc test cases for linear-address masking
selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address
masking
selftests/x86/lam: Add io_uring test cases for linear-address masking
selftests/x86/lam: Add inherit test cases for linear-address masking
selftests/x86/lam: Add tests cases for LAM_U48
arch/arm64/include/asm/memory.h | 4 +-
arch/arm64/include/asm/signal.h | 2 +-
arch/arm64/include/asm/uaccess.h | 4 +-
arch/arm64/kernel/hw_breakpoint.c | 2 +-
arch/arm64/kernel/traps.c | 4 +-
arch/arm64/mm/fault.c | 10 +-
arch/sparc/include/asm/pgtable_64.h | 2 +-
arch/sparc/include/asm/uaccess_64.h | 2 +
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/elf.h | 3 +-
arch/x86/include/asm/mmu.h | 6 +
arch/x86/include/asm/mmu_context.h | 58 ++
arch/x86/include/asm/processor-flags.h | 2 +-
arch/x86/include/asm/tlbflush.h | 36 +
arch/x86/include/asm/uaccess.h | 42 +-
arch/x86/include/uapi/asm/prctl.h | 3 +
arch/x86/include/uapi/asm/processor-flags.h | 6 +
arch/x86/kernel/Makefile | 2 +
arch/x86/kernel/fpu/xstate.c | 47 -
arch/x86/kernel/proc.c | 60 ++
arch/x86/kernel/process.c | 3 +
arch/x86/kernel/process_64.c | 83 +-
arch/x86/kernel/sys_x86_64.c | 5 +-
arch/x86/mm/hugetlbpage.c | 6 +-
arch/x86/mm/mmap.c | 10 +-
arch/x86/mm/tlb.c | 42 +-
.../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 2 +-
drivers/gpu/drm/radeon/radeon_gem.c | 2 +-
drivers/infiniband/hw/mlx4/mr.c | 2 +-
drivers/media/common/videobuf2/frame_vector.c | 2 +-
drivers/media/v4l2-core/videobuf-dma-contig.c | 2 +-
.../staging/media/atomisp/pci/hmm/hmm_bo.c | 2 +-
drivers/tee/tee_shm.c | 2 +-
drivers/vfio/vfio_iommu_type1.c | 2 +-
fs/proc/task_mmu.c | 2 +-
include/linux/mm.h | 11 -
include/linux/uaccess.h | 15 +
lib/strncpy_from_user.c | 2 +-
lib/strnlen_user.c | 2 +-
mm/gup.c | 6 +-
mm/madvise.c | 2 +-
mm/mempolicy.c | 6 +-
mm/migrate.c | 2 +-
mm/mincore.c | 2 +-
mm/mlock.c | 4 +-
mm/mmap.c | 2 +-
mm/mprotect.c | 2 +-
mm/mremap.c | 2 +-
mm/msync.c | 2 +-
tools/testing/selftests/x86/Makefile | 2 +-
tools/testing/selftests/x86/lam.c | 913 ++++++++++++++++++
virt/kvm/kvm_main.c | 2 +-
53 files changed, 1315 insertions(+), 127 deletions(-)
create mode 100644 arch/x86/kernel/proc.c
create mode 100644 tools/testing/selftests/x86/lam.c
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2.35.1
