TIF_FOREIGN_FPSTATE is a 'convenience' flag that should reflect whether
the current CPU holds the most recent user mode FP/SIMD state of the
current task. It combines two conditions:
- whether the current CPU's FP/SIMD state belongs to the task;
- whether that state is the most recent associated with the task (as a
  task may have executed on other CPUs as well).

When a task is scheduled in and TIF_KERNEL_FPSTATE is set, it means the
task was in a kernel mode NEON section when it was scheduled out, and so
the kernel mode FP/SIMD state is restored. Since this implies that the
current CPU is *not* holding the most recent user mode FP/SIMD state of
the current task, the TIF_FOREIGN_FPSTATE flag is set too, so that the
user mode FP/SIMD state is reloaded from memory when returning to
userland.

However, the task may be scheduled out after completing the kernel mode
NEON section, but before returning to userland. When this happens, the
TIF_FOREIGN_FPSTATE flag will not be preserved, but will be set as usual
the next time the task is scheduled in, and will be based on the above
conditions.

This means that, rather than setting TIF_FOREIGN_FPSTATE when scheduling
in a task with TIF_KERNEL_FPSTATE set, the underlying state should be
updated so that TIF_FOREIGN_FPSTATE will assume the expected value as a
result.

So instead, call fpsimd_flush_cpu_state(), which takes care of this.

Closes: https://lore.kernel.org/all/cb8822182231850108fa43e0446a4c7f@kernel.org
Reported-by: Johannes Nixdorf <mixi@shadowice.org>
Fixes: aefbab8e77eb ("arm64: fpsimd: Preserve/restore kernel mode NEON at context switch")
Cc: Mark Brown <broonie@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Janne Grunau <j@jannau.net>
Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Janne Grunau <j@jannau.net>
Tested-by: Johannes Nixdorf <mixi@shadowice.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240522091335.335346-2-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>

This reverts commit b8995a18417088bb53f87c49d200ec72a9dd4ec1.

Ard managed to reproduce the dm-crypt corruption problem and got to the
bottom of it, so re-apply the problematic patch in preparation for
fixing things properly.

Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

This reverts commit 2632e25217696712681dd1f3ecc0d71624ea3b23.

Johannes (and others) report data corruption with dm-crypt on Apple M1
which has been bisected to this change. Revert the offending commit
while we figure out what's going on.

Cc: stable@vger.kernel.org
Reported-by: Johannes Nixdorf <mixi@shadowice.org>
Link: https://lore.kernel.org/all/D1B7GPIR9K1E.5JFV37G0YTIF@shadowice.org/
Signed-off-by: Will Deacon <will@kernel.org>

Pull arm64 updates from Catalin Marinas:
 "The major features are support for LPA2 (52-bit VA/PA with 4K and 16K
  pages), the dpISA extension and Rust enabled on arm64. The changes are
  mostly contained within the usual arch/arm64/, drivers/perf, the arm64
  Documentation and kselftests. The exception is the Rust support which
  touches some generic build files.

  Summary:

   - Reorganise the arm64 kernel VA space and add support for LPA2 (at
     stage 1, KVM stage 2 was merged earlier) - 52-bit VA/PA address
     range with 4KB and 16KB pages

   - Enable Rust on arm64

   - Support for the 2023 dpISA extensions (data processing ISA), host
     only

   - arm64 perf updates:

      - StarFive's StarLink (integrates one or more CPU cores with a
        shared L3 memory system) PMU support

      - Enable HiSilicon Erratum 162700402 quirk for HIP09

      - Several updates for the HiSilicon PCIe PMU driver

      - Arm CoreSight PMU support

      - Convert all drivers under drivers/perf/ to use .remove_new()

   - Miscellaneous:

      - Don't enable workarounds for "rare" errata by default

      - Clean up the DAIF flags handling for EL0 returns (in preparation
        for NMI support)

      - Kselftest update for ptrace()

      - Update some of the sysreg field definitions

      - Slight improvement in the code generation for inline asm I/O
        accessors to permit offset addressing

      - kretprobes: acquire regs via a BRK exception (previously done
        via a trampoline handler)

      - SVE/SME cleanups, comment updates

      - Allow CALL_OPS+CC_OPTIMIZE_FOR_SIZE with clang (previously
        disabled due to gcc silently ignoring -falign-functions=N)"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (134 commits)
  Revert "mm: add arch hook to validate mmap() prot flags"
  Revert "arm64: mm: add support for WXN memory translation attribute"
  Revert "ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512"
  ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512
  kselftest/arm64: Add 2023 DPISA hwcap test coverage
  kselftest/arm64: Add basic FPMR test
  kselftest/arm64: Handle FPMR context in generic signal frame parser
  arm64/hwcap: Define hwcaps for 2023 DPISA features
  arm64/ptrace: Expose FPMR via ptrace
  arm64/signal: Add FPMR signal handling
  arm64/fpsimd: Support FEAT_FPMR
  arm64/fpsimd: Enable host kernel access to FPMR
  arm64/cpufeature: Hook new identification registers up to cpufeature
  docs: perf: Fix build warning of hisi-pcie-pmu.rst
  perf: starfive: Only allow COMPILE_TEST for 64-bit architectures
  MAINTAINERS: Add entry for StarFive StarLink PMU
  docs: perf: Add description for StarFive's StarLink PMU
  dt-bindings: perf: starfive: Add JH8100 StarLink PMU
  perf: starfive: Add StarLink PMU support
  docs: perf: Update usage for target filter of hisi-pcie-pmu
  ...

* arm64/for-next/perf: (39 commits)
  docs: perf: Fix build warning of hisi-pcie-pmu.rst
  perf: starfive: Only allow COMPILE_TEST for 64-bit architectures
  MAINTAINERS: Add entry for StarFive StarLink PMU
  docs: perf: Add description for StarFive's StarLink PMU
  dt-bindings: perf: starfive: Add JH8100 StarLink PMU
  perf: starfive: Add StarLink PMU support
  docs: perf: Update usage for target filter of hisi-pcie-pmu
  drivers/perf: hisi_pcie: Merge find_related_event() and get_event_idx()
  drivers/perf: hisi_pcie: Relax the check on related events
  drivers/perf: hisi_pcie: Check the target filter properly
  drivers/perf: hisi_pcie: Add more events for counting TLP bandwidth
  drivers/perf: hisi_pcie: Fix incorrect counting under metric mode
  drivers/perf: hisi_pcie: Introduce hisi_pcie_pmu_get_event_ctrl_val()
  drivers/perf: hisi_pcie: Rename hisi_pcie_pmu_{config,clear}_filter()
  drivers/perf: hisi: Enable HiSilicon Erratum 162700402 quirk for HIP09
  perf/arm_cspmu: Add devicetree support
  dt-bindings/perf: Add Arm CoreSight PMU
  perf/arm_cspmu: Simplify counter reset
  perf/arm_cspmu: Simplify attribute groups
  perf/arm_cspmu: Simplify initialisation
  ...

* for-next/reorg-va-space:
  : Reorganise the arm64 kernel VA space in preparation for LPA2 support
  : (52-bit VA/PA).
  arm64: kaslr: Adjust randomization range dynamically
  arm64: mm: Reclaim unused vmemmap region for vmalloc use
  arm64: vmemmap: Avoid base2 order of struct page size to dimension region
  arm64: ptdump: Discover start of vmemmap region at runtime
  arm64: ptdump: Allow all region boundaries to be defined at boot time
  arm64: mm: Move fixmap region above vmemmap region
  arm64: mm: Move PCI I/O emulation region above the vmemmap region

* for-next/rust-for-arm64:
  : Enable Rust support for arm64
  arm64: rust: Enable Rust support for AArch64
  rust: Refactor the build target to allow the use of builtin targets

* for-next/misc:
  : Miscellaneous arm64 patches
  ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512
  arm64: Remove enable_daif macro
  arm64/hw_breakpoint: Directly use ESR_ELx_WNR for an watchpoint exception
  arm64: cpufeatures: Clean up temporary variable to simplify code
  arm64: Update setup_arch() comment on interrupt masking
  arm64: remove unnecessary ifdefs around is_compat_task()
  arm64: ftrace: Don't forbid CALL_OPS+CC_OPTIMIZE_FOR_SIZE with Clang
  arm64/sme: Ensure that all fields in SMCR_EL1 are set to known values
  arm64/sve: Ensure that all fields in ZCR_EL1 are set to known values
  arm64/sve: Document that __SVE_VQ_MAX is much larger than needed
  arm64: make member of struct pt_regs and it's offset macro in the same order
  arm64: remove unneeded BUILD_BUG_ON assertion
  arm64: kretprobes: acquire the regs via a BRK exception
  arm64: io: permit offset addressing
  arm64: errata: Don't enable workarounds for "rare" errata by default

* for-next/daif-cleanup:
  : Clean up DAIF handling for EL0 returns
  arm64: Unmask Debug + SError in do_notify_resume()
  arm64: Move do_notify_resume() to entry-common.c
  arm64: Simplify do_notify_resume() DAIF masking

* for-next/kselftest:
  : Miscellaneous arm64 kselftest patches
  kselftest/arm64: Test that ptrace takes effect in the target process

* for-next/documentation:
  : arm64 documentation patches
  arm64/sme: Remove spurious 'is' in SME documentation
  arm64/fp: Clarify effect of setting an unsupported system VL
  arm64/sme: Fix cut'n'paste in ABI document
  arm64/sve: Remove bitrotted comment about syscall behaviour

* for-next/sysreg:
  : sysreg updates
  arm64/sysreg: Update ID_AA64DFR0_EL1 register
  arm64/sysreg: Update ID_DFR0_EL1 register fields
  arm64/sysreg: Add register fields for ID_AA64DFR1_EL1

* for-next/dpisa:
  : Support for 2023 dpISA extensions
  kselftest/arm64: Add 2023 DPISA hwcap test coverage
  kselftest/arm64: Add basic FPMR test
  kselftest/arm64: Handle FPMR context in generic signal frame parser
  arm64/hwcap: Define hwcaps for 2023 DPISA features
  arm64/ptrace: Expose FPMR via ptrace
  arm64/signal: Add FPMR signal handling
  arm64/fpsimd: Support FEAT_FPMR
  arm64/fpsimd: Enable host kernel access to FPMR
  arm64/cpufeature: Hook new identification registers up to cpufeature

FEAT_FPMR defines a new EL0 accessible register FPMR use to configure the
FP8 related features added to the architecture at the same time. Detect
support for this register and context switch it for EL0 when present.

Due to the sharing of responsibility for saving floating point state
between the host kernel and KVM FP8 support is not yet implemented in KVM
and a stub similar to that used for SVCR is provided for FPMR in order to
avoid bisection issues. To make it easier to share host state with the
hypervisor we store FPMR as a hardened usercopy field in uw (along with
some padding).

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-3-c568edc8ed7f@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

At present nothing in our CPU initialisation code ever sets unknown fields
in SMCR_EL1 to known values, all updates to SMCR_EL1 are read/modify/write
sequences. All the unknown fields are RES0, explicitly initialise them as
such to avoid future surprises.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240213-arm64-fp-init-vec-cr-v1-2-7e7c2d584f26@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

At present nothing in our CPU initialisation code ever sets unknown fields
in ZCR_EL1 to known values, all updates to ZCR_EL1 are read/modify/write
sequences for LEN. All the unknown fields are RES0, explicitly initialise
them as such to avoid future surprises.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240213-arm64-fp-init-vec-cr-v1-1-7e7c2d584f26@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The fields in SMCR_EL1 reset to an architecturally UNKNOWN value. Since we
do not otherwise manage the traps configured in this register at runtime we
need to reconfigure them after a suspend in case nothing else was kind
enough to preserve them for us. Do so for SMCR_EL1.EZT0.

Fixes: d4913eee152d ("arm64/sme: Add basic enumeration for SME2")
Reported-by: Jackson Cooper-Driver <Jackson.Cooper-Driver@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240213-arm64-sme-resume-v3-2-17e05e493471@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

The fields in SMCR_EL1 and SMPRI_EL1 reset to an architecturally UNKNOWN
value. Since we do not otherwise manage the traps configured in this
register at runtime we need to reconfigure them after a suspend in case
nothing else was kind enough to preserve them for us.

The vector length will be restored as part of restoring the SME state for
the next SME using task.

Fixes: a1f4ccd25cc2 ("arm64/sme: Provide Kconfig for SME")
Reported-by: Jackson Cooper-Driver <Jackson.Cooper-Driver@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240213-arm64-sme-resume-v3-1-17e05e493471@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>