Full LTO takes the '-mbranch-protection=none' passed to the compiler
when generating the dynamic shadow call stack patching code as a hint to
stop emitting PAC instructions altogether. (Thin LTO appears unaffected
by this)

Work around this by stripping unwind tables from the object in question,
which should be sufficient to prevent the patching code from attempting
to patch itself.

Fixes: 3b619e22 ("arm64: implement dynamic shadow call stack for Clang")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240110132619.258809-2-ardb+git@google.comSigned-off-by: Will Deacon <will@kernel.org>

Sorting include files in alphabetic order in
drivers/tty/serial/samsung.c revealed the following error:

In file included from drivers/tty/serial/samsung_tty.c:24:
./arch/arm64/include/asm/irq.h:9:43: error: unknown type name ‘cpumask_t’
    9 | void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu);
      |                                           ^~~~~~~~~

Include cpumask.h to avoid unknown type errors for parents of irq.h that
don't include cpumask.h.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20240110074007.4020016-1-tudor.ambarus@linaro.orgSigned-off-by: Will Deacon <will@kernel.org>

Merge in arm64 fixes queued for 6.7 so that kpti_install_ng_mappings()
can be updated to use arm64_kernel_unmapped_at_el0() instead of checking
the ARM64_UNMAP_KERNEL_AT_EL0 CPU capability directly.

* for-next/fixes:
  arm64: mm: Always make sw-dirty PTEs hw-dirty in pte_modify
  perf/arm-cmn: Fail DTC counter allocation correctly
  arm64: Avoid enabling KPTI unnecessarily

* for-next/sysregs:
  arm64/sysreg: Add missing system instruction definitions for FGT
  arm64/sysreg: Add missing system register definitions for FGT
  arm64/sysreg: Add missing ExtTrcBuff field definition to ID_AA64DFR0_EL1
  arm64/sysreg: Add missing Pauth_LR field definitions to ID_AA64ISAR1_EL1
  arm64/sysreg: Add new system registers for GCS
  arm64/sysreg: Add definition for FPMR
  arm64/sysreg: Update HCRX_EL2 definition for DDI0601 2023-09
  arm64/sysreg: Update SCTLR_EL1 for DDI0601 2023-09
  arm64/sysreg: Update ID_AA64SMFR0_EL1 definition for DDI0601 2023-09
  arm64/sysreg: Add definition for ID_AA64FPFR0_EL1
  arm64/sysreg: Add definition for ID_AA64ISAR3_EL1
  arm64/sysreg: Update ID_AA64ISAR2_EL1 defintion for DDI0601 2023-09
  arm64/sysreg: Add definition for ID_AA64PFR2_EL1
  arm64/sysreg: update CPACR_EL1 register
  arm64/sysreg: add system register POR_EL{0,1}
  arm64/sysreg: Add definition for HAFGRTR_EL2
  arm64/sysreg: Update HFGITR_EL2 definiton to DDI0601 2023-09

* for-next/stacktrace:
  arm64: stacktrace: factor out kunwind_stack_walk()
  arm64: stacktrace: factor out kernel unwind state

* for-next/selftests:
  kselftest/arm64: Don't probe the current VL for unsupported vector types
  kselftest/arm64: Log SVCR when the SME tests barf
  kselftest/arm64: Improve output for skipped TPIDR2 ABI test

* for-next/rip-vpipt:
  arm64: Rename reserved values for CTR_EL0.L1Ip
  arm64: Kill detection of VPIPT i-cache policy
  KVM: arm64: Remove VPIPT I-cache handling

* for-next/perf: (30 commits)
  arm: perf: Fix ARCH=arm build with GCC
  MAINTAINERS: add maintainers for DesignWare PCIe PMU driver
  drivers/perf: add DesignWare PCIe PMU driver
  PCI: Move pci_clear_and_set_dword() helper to PCI header
  PCI: Add Alibaba Vendor ID to linux/pci_ids.h
  docs: perf: Add description for Synopsys DesignWare PCIe PMU driver
  Revert "perf/arm_dmc620: Remove duplicate format attribute #defines"
  Documentation: arm64: Document the PMU event counting threshold feature
  arm64: perf: Add support for event counting threshold
  arm: pmu: Move error message and -EOPNOTSUPP to individual PMUs
  KVM: selftests: aarch64: Update tools copy of arm_pmuv3.h
  perf/arm_dmc620: Remove duplicate format attribute #defines
  arm: pmu: Share user ABI format mechanism with SPE
  arm64: perf: Include threshold control fields in PMEVTYPER mask
  arm: perf: Convert remaining fields to use GENMASK
  arm: perf: Use GENMASK for PMMIR fields
  arm: perf/kvm: Use GENMASK for ARMV8_PMU_PMCR_N
  arm: perf: Remove inlines from arm_pmuv3.c
  drivers/perf: arm_dsu_pmu: Remove kerneldoc-style comment syntax
  drivers/perf: Remove usage of the deprecated ida_simple_xx() API
  ...

* for-next/mm:
  arm64: irq: set the correct node for shadow call stack
  arm64: irq: set the correct node for VMAP stack

* for-next/misc:
  arm64: memory: remove duplicated include
  arm64: Delete the zero_za macro
  Documentation/arch/arm64: Fix typo

* for-next/lpa2-prep:
  arm64: mm: get rid of kimage_vaddr global variable
  arm64: mm: Take potential load offset into account when KASLR is off
  arm64: kernel: Disable latent_entropy GCC plugin in early C runtime
  arm64: Add ARM64_HAS_LPA2 CPU capability
  arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2]
  arm64/mm: Update tlb invalidation routines for FEAT_LPA2
  arm64/mm: Add lpa2_is_enabled() kvm_lpa2_is_enabled() stubs
  arm64/mm: Modify range-based tlbi to decrement scale

* for-next/kbuild:
  efi/libstub: zboot: do not use $(shell ...) in cmd_copy_and_pad
  arm64: properly install vmlinuz.efi
  arm64: replace <asm-generic/export.h> with <linux/export.h>
  arm64: vdso32: rename 32-bit debug vdso to vdso32.so.dbg

* for-next/fpsimd:
  arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD
  arm64: fpsimd: Preserve/restore kernel mode NEON at context switch
  arm64: fpsimd: Drop unneeded 'busy' flag

* for-next/early-idreg-overrides:
  arm64/kernel: Move 'nokaslr' parsing out of early idreg code
  arm64: idreg-override: Avoid kstrtou64() to parse a single hex digit
  arm64: idreg-override: Avoid sprintf() for simple string concatenation
  arm64: idreg-override: avoid strlen() to check for empty strings
  arm64: idreg-override: Avoid parameq() and parameqn()
  arm64: idreg-override: Prepare for place relative reloc patching
  arm64: idreg-override: Omit non-NULL checks for override pointer

* for-next/cpufeature:
  arm64: Align boot cpucap handling with system cpucap handling
  arm64: Cleanup system cpucap handling
  arm64: Kconfig: drop KAISER reference from KPTI option description
  arm64: mm: Only map KPTI trampoline if it is going to be used
  arm64: Get rid of ARM64_HAS_NO_HW_PREFETCH

The vec-syscfg selftest verifies that setting the VL of the currently
tested vector type does not disrupt the VL of the other vector type. To do
this it records the current vector length for each type but neglects to
guard this with a check for that vector type actually being supported. Add
one, using a helper function which we also update all the other instances
of this pattern.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231218-kselftest-arm64-vec-syscfg-rdvl-v1-1-0ac22d47e81f@kernel.orgSigned-off-by: Will Deacon <will@kernel.org>

You do not need to use $(shell ...) in recipe lines, as they are already
executed in a shell. An alternative solution is $$(...), which is an
escaped sequence of the shell's command substituion, $(...).

For this case, there is a reason to avoid $(shell ...).

Kbuild detects command changes by using the if_changed macro, which
compares the previous command recorded in .*.cmd with the current
command from Makefile. If they differ, Kbuild re-runs the build rule.

To diff the commands, Make must expand $(shell ...) first. It means that
hexdump is executed every time, even when nothing needs rebuilding. If
Kbuild determines that vmlinux.bin needs rebuilding, hexdump will be
executed again to evaluate the 'cmd' macro, one more time to really
build vmlinux.bin, and finally yet again to record the expanded command
into .*.cmd.

Replace $(shell ...) with $$(...) to avoid multiple, unnecessay shell
evaluations. Since Make is agnostic about the shell code, $(...), the
if_changed macro compares the string "$(hexdump -s16 -n4 ...)" verbatim,
so hexdump is run only for building vmlinux.bin.

For the same reason, $(shell ...) in EFI_ZBOOT_OBJCOPY_FLAGS should be
eliminated.

While I was here, I replaced '&&' with ';' because a command for
if_changed is executed with 'set -e'.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20231218080127.907460-1-masahiroy@kernel.orgSigned-off-by: Will Deacon <will@kernel.org>

If you select CONFIG_EFI_ZBOOT, we will generate vmlinuz.efi, and then
when we go to install the kernel we'll install the vmlinux instead
because install.sh only recognizes Image.gz as wanting the compressed
install image.  With CONFIG_EFI_ZBOOT we don't get the proper kernel
installed, which means it doesn't boot, which makes for a very confused
and subsequently angry kernel developer.

Fix this by properly installing our compressed kernel if we've enabled
CONFIG_EFI_ZBOOT.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Cc: <stable@vger.kernel.org> # 6.1.x
Fixes: c37b830f ("arm64: efi: enable generic EFI compressed boot")
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/6edb1402769c2c14c4fbef8f7eaedb3167558789.1702570674.git.josef@toxicpanda.comSigned-off-by: Will Deacon <will@kernel.org>

Add the definitions of missing system instructions that are
trappable by fine grain traps. The definitions are based on
DDI0602 2023-09.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20231214100158.2305400-5-tabba@google.comSigned-off-by: Will Deacon <will@kernel.org>

Add the definitions of missing system registers that are
trappable by fine grain traps. The definitions are based on
DDI0601 2023-09.
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231214100158.2305400-4-tabba@google.comSigned-off-by: Will Deacon <will@kernel.org>

Add the ExtTrcBuff field definitions to ID_AA64DFR0_EL1 from
DDI0601 2023-09.

This field isn't used yet. Adding it for completeness and because
it will be used in future patches.
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231214100158.2305400-3-tabba@google.comSigned-off-by: Will Deacon <will@kernel.org>

Add the Pauth_LR field definitions to ID_AA64ISAR1_EL1, based on
DDI0601 2023-09.

These fields aren't used yet. Adding them for completeness and
consistency (definition already exists for ID_AA64ISAR2_EL1).
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231214100158.2305400-2-tabba@google.comSigned-off-by: Will Deacon <will@kernel.org>

remove duplicated include
Signed-off-by: Wang Jinchao <wangjinchao@xfusion.com>
Link: https://lore.kernel.org/r/202312151439+0800-wangjinchao@xfusion.comSigned-off-by: Will Deacon <will@kernel.org>

LLVM ignores everything inside the if statement and doesn't generate
errors, but GCC doesn't ignore it, resulting in the following error:

  drivers/perf/arm_pmuv3.c: In function ‘armv8pmu_write_evtype’:
  include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow]
  34 |         (((~UL(0)) - (UL(1) << (l)) + 1) & \

Fix it by using GENMASK_ULL which doesn't overflow on arm32 (even though
the value is never used there).

Fixes: 3115ee02 ("arm64: perf: Include threshold control fields in PMEVTYPER mask")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Closes: https://lore.kernel.org/linux-arm-kernel/20231215120817.h2f3akgv72zhrtqo@pengutronix.de/Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231215175648.3397170-2-james.clark@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Currently the detection+enablement of boot cpucaps is separate from the
patching of boot cpucap alternatives, which means there's a period where
cpus_have_cap($CAP) and alternative_has_cap($CAP) may be mismatched.

It would be preferable to manage the boot cpucaps in the same way as the
system cpucaps, both for clarity and to minimize the risk of accidental
usage of code relying upon an alternative which has not yet been
patched.

This patch aligns the handling of boot cpucaps with the handling of
system cpucaps:

* The existing setup_boot_cpu_capabilities() function is moved to be
  closer to the setup_system_capabilities() and setup_system_features()
  functions so that they're more clearly related and more likely to be
  updated together in future.

* The patching of boot cpucap alternatives is moved into
  setup_boot_cpu_capabilities(), immediately after boot cpucaps are
  detected and enabled.

* A new setup_boot_cpu_features() function is added to mirror
  setup_system_features(); this handles initialization of cpucap data
  structures and calls setup_boot_cpu_capabilities(). This makes
  init_cpu_features() a closer mirror to update_cpu_features(), and
  makes smp_prepare_boot_cpu() a closer mirror to smp_cpus_done().

Importantly, while these changes alter the structure of the code, they
retain the existing order of calls to:

  init_cpu_features(); // prefix initializing feature regs
  init_cpucap_indirect_list();
  detect_system_supports_pseudo_nmi();
  update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
  enable_cpu_capabilities(SCOPE_BOOT_CPU);
  apply_boot_alternatives();

... and hence there should be no functional change as a result of this
patch; this is purely a structural cleanup.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20231212170910.3745497-3-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Recent changes to remove cpus_have_const_cap() introduced new users of
cpus_have_cap() in the period between detecting system cpucaps and
patching alternatives. It would be preferable to defer these until after
the relevant cpucaps have been patched so that these can use the usual
feature check helper functions, which is clearer and has less risk of
accidental usage of code relying upon an alternative which has not yet
been patched.

This patch reworks the system-wide cpucap detection and patching to
minimize this transient period:

* The detection, enablement, and patching of system cpucaps is moved
  into a new setup_system_capabilities() function so that these can be
  grouped together more clearly, with no other functions called in the
  period between detection and patching. This is called from
  setup_system_features() before the subsequent checks that depend on
  the cpucaps.

  The logging of TTBR0 PAN and cpucaps with a mask is also moved here to
  keep these as close as possible to update_cpu_capabilities().

  At the same time, comments are corrected and improved to make the
  intent clearer.

* As hyp_mode_check() only tests system register values (not hwcaps) and
  must be called prior to patching, the call to hyp_mode_check() is
  moved before the call to setup_system_features().

* In setup_system_features(), the use of system_uses_ttbr0_pan() is
  restored, now that this occurs after alternatives are patched. This is
  a partial revert of commit:

    53d62e99 ("arm64: Avoid cpus_have_const_cap() for ARM64_HAS_PAN")

* In sve_setup() and sme_setup(), the use of system_supports_sve() and
  system_supports_sme() respectively are restored, now that these occur
  after alternatives are patched. This is a partial revert of commit:

    a76521d1 ("arm64: Avoid cpus_have_const_cap() for ARM64_{SVE,SME,SME2,FA64}")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20231212170910.3745497-2-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Add maintainers for Synopsys DesignWare PCIe PMU driver and driver
document.
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Link: https://lore.kernel.org/r/20231208025652.87192-6-xueshuai@linux.alibaba.comSigned-off-by: Will Deacon <will@kernel.org>

This commit adds the PCIe Performance Monitoring Unit (PMU) driver support
for T-Head Yitian SoC chip. Yitian is based on the Synopsys PCI Express
Core controller IP which provides statistics feature. The PMU is a PCIe
configuration space register block provided by each PCIe Root Port in a
Vendor-Specific Extended Capability named RAS D.E.S (Debug, Error
injection, and Statistics).

To facilitate collection of statistics the controller provides the
following two features for each Root Port:

- one 64-bit counter for Time Based Analysis (RX/TX data throughput and
  time spent in each low-power LTSSM state) and
- one 32-bit counter for Event Counting (error and non-error events for
  a specified lane)

Note: There is no interrupt for counter overflow.

This driver adds PMU devices for each PCIe Root Port. And the PMU device is
named based the BDF of Root Port. For example,

    30:03.0 PCI bridge: Device 1ded:8000 (rev 01)

the PMU device name for this Root Port is dwc_rootport_3018.

Example usage of counting PCIe RX TLP data payload (Units of bytes)::

    $# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/

average RX bandwidth can be calculated like this:

    PCIe TX Bandwidth = Rx_PCIe_TLP_Data_Payload / Measure_Time_Window
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-and-tested-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20231208025652.87192-5-xueshuai@linux.alibaba.com
[will: Fix sparse error due to use of uninitialised 'vsec' symbol in
 dwc_pcie_match_des_cap()]
Signed-off-by: Will Deacon <will@kernel.org>

The clear and set pattern is commonly used for accessing PCI config,
move the helper pci_clear_and_set_dword() from aspm.c into PCI header.
In addition, rename to pci_clear_and_set_config_dword() to retain the
"config" information and match the other accessors.

No functional change intended.
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20231208025652.87192-4-xueshuai@linux.alibaba.comSigned-off-by: Will Deacon <will@kernel.org>

The Alibaba Vendor ID (0x1ded) is now used by Alibaba elasticRDMA ("erdma")
and will be shared with the upcoming PCIe PMU ("dwc_pcie_pmu"). Move the
Vendor ID to linux/pci_ids.h so that it can shared by several drivers
later.
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>	# pci_ids.h
Tested-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20231208025652.87192-3-xueshuai@linux.alibaba.comSigned-off-by: Will Deacon <will@kernel.org>

Alibaba's T-Head Yitan 710 SoC includes Synopsys' DesignWare Core PCIe
controller which implements PMU for performance and functional debugging to
facilitate system maintenance.

Document it to provide guidance on how to use it.
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Tested-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20231208025652.87192-2-xueshuai@linux.alibaba.comSigned-off-by: Will Deacon <will@kernel.org>

The init_irq_stacks() has been changed to use the correct node:
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?id=75b5e0bf90bf

The init_irq_scs() has the same issue with init_irq_stacks():
	cpu_to_node() is not initialized yet, it does not work.

This patch uses early_cpu_to_node() to set the init_irq_scs()
with the correct node.
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20231213012046.12014-1-shijie@os.amperecomputing.comSigned-off-by: Will Deacon <will@kernel.org>

This reverts commit a5f4ca68.

Pulling in the Arm-specific 'linux/perf/arm_pmu.h' header breaks the
allmodconfig build for x86:

> In file included from drivers/perf/arm_dmc620_pmu.c:26:
> include/linux/perf/arm_pmu.h:15:10: fatal error: asm/cputype.h: No such file or directory
>    15 | #include <asm/cputype.h>
>       |          ^~~~~~~~~~~~~~~

Just put things back like they were so that the driver can continue to
be compile-tested on a variety of architectures.

Link: https://lore.kernel.org/r/20231213100931.12d9d85e@canb.auug.org.auReported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Will Deacon <will@kernel.org>

It is currently possible for a userspace application to enter an
infinite page fault loop when using HugeTLB pages implemented with
contiguous PTEs when HAFDBS is not available. This happens because:

1. The kernel may sometimes write PTEs that are sw-dirty but hw-clean
   (PTE_DIRTY | PTE_RDONLY | PTE_WRITE).

2. If, during a write, the CPU uses a sw-dirty, hw-clean PTE in handling
   the memory access on a system without HAFDBS, we will get a page
   fault.

3. HugeTLB will check if it needs to update the dirty bits on the PTE.
   For contiguous PTEs, it will check to see if the pgprot bits need
   updating. In this case, HugeTLB wants to write a sequence of
   sw-dirty, hw-dirty PTEs, but it finds that all the PTEs it is about
   to overwrite are all pte_dirty() (pte_sw_dirty() => pte_dirty()),
   so it thinks no update is necessary.

We can get the kernel to write a sw-dirty, hw-clean PTE with the
following steps (showing the relevant VMA flags and pgprot bits):

i.   Create a valid, writable contiguous PTE.
       VMA vmflags:     VM_SHARED | VM_READ | VM_WRITE
       VMA pgprot bits: PTE_RDONLY | PTE_WRITE
       PTE pgprot bits: PTE_DIRTY | PTE_WRITE

ii.  mprotect the VMA to PROT_NONE.
       VMA vmflags:     VM_SHARED
       VMA pgprot bits: PTE_RDONLY
       PTE pgprot bits: PTE_DIRTY | PTE_RDONLY

iii. mprotect the VMA back to PROT_READ | PROT_WRITE.
       VMA vmflags:     VM_SHARED | VM_READ | VM_WRITE
       VMA pgprot bits: PTE_RDONLY | PTE_WRITE
       PTE pgprot bits: PTE_DIRTY | PTE_WRITE | PTE_RDONLY

Make it impossible to create a writeable sw-dirty, hw-clean PTE with
pte_modify(). Such a PTE should be impossible to create, and there may
be places that assume that pte_dirty() implies pte_hw_dirty().
Signed-off-by: James Houghton <jthoughton@google.com>
Fixes: 031e6e6b ("arm64: hugetlb: Avoid unnecessary clearing in huge_ptep_set_access_flags")
Cc: <stable@vger.kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://lore.kernel.org/r/20231204172646.2541916-3-jthoughton@google.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

Now that kernel mode FPSIMD state is context switched along with other
task state, we can enable the existing logic that keeps track of which
task's FPSIMD state the CPU is holding in its registers. If it is the
context of the task that we are switching to, we can elide the reload of
the FPSIMD state from memory.

Note that we also need to check whether the FPSIMD state on this CPU is
the most recent: if a task gets migrated away and back again, the state
in memory may be more recent than the state in the CPU. So add another
CPU id field to task_struct to keep track of this. (We could reuse the
existing CPU id field used for user mode context, but that might result
in user state to be discarded unnecessarily, given that two distinct
CPUs could be holding the most recent user mode state and the most
recent kernel mode state)
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20231208113218.3001940-9-ardb@google.comSigned-off-by: Will Deacon <will@kernel.org>

Currently, the FPSIMD register file is not preserved and restored along
with the general registers on exception entry/exit or context switch.
For this reason, we disable preemption when enabling FPSIMD for kernel
mode use in task context, and suspend the processing of softirqs so that
there are no concurrent uses in the kernel. (Kernel mode FPSIMD may not
be used at all in other contexts).

Disabling preemption while doing CPU intensive work on inputs of
potentially unbounded size is bad for real-time performance, which is
why we try and ensure that SIMD crypto code does not operate on more
than ~4k at a time, which is an arbitrary limit and requires assembler
code to implement efficiently.

We can avoid the need for disabling preemption if we can ensure that any
in-kernel users of the NEON will not lose the FPSIMD register state
across a context switch. And given that disabling softirqs implicitly
disables preemption as well, we will also have to ensure that a softirq
that runs code using FPSIMD can safely interrupt an in-kernel user.

So introduce a thread_info flag TIF_KERNEL_FPSTATE, and modify the
context switch hook for FPSIMD to preserve and restore the kernel mode
FPSIMD to/from struct thread_struct when it is set. This avoids any
scheduling blackouts due to prolonged use of FPSIMD in kernel mode,
without the need for manual yielding.

In order to support softirq processing while FPSIMD is being used in
kernel task context, use the same flag to decide whether the kernel mode
FPSIMD state needs to be preserved and restored before allowing FPSIMD
to be used in softirq context.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20231208113218.3001940-8-ardb@google.comSigned-off-by: Will Deacon <will@kernel.org>

Kernel mode NEON will preserve the user mode FPSIMD state by saving it
into the task struct before clobbering the registers. In order to avoid
the need for preserving kernel mode state too, we disallow nested use of
kernel mode NEON, i..e, use in softirq context while the interrupted
task context was using kernel mode NEON too.

Originally, this policy was implemented using a per-CPU flag which was
exposed via may_use_simd(), requiring the users of the kernel mode NEON
to deal with the possibility that it might return false, and having NEON
and non-NEON code paths. This policy was changed by commit
13150149 ("arm64: fpsimd: run kernel mode NEON with softirqs
disabled"), and now, softirq processing is disabled entirely instead,
and so may_use_simd() can never fail when called from task or softirq
context.

This means we can drop the fpsimd_context_busy flag entirely, and
instead, ensure that we disable softirq processing in places where we
formerly relied on the flag for preventing races in the FPSIMD preserve
routines.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231208113218.3001940-7-ardb@google.com
[will: Folded in fix from CAMj1kXFhzbJRyWHELCivQW1yJaF=p07LLtbuyXYX3G1WtsdyQg@mail.gmail.com]
Signed-off-by: Will Deacon <will@kernel.org>

Calling arm_cmn_event_clear() before all DTC indices are allocated is
wrong, and can lead to arm_cmn_event_add() erroneously clearing live
counters from full DTCs where allocation fails. Since the DTC counters
are only updated by arm_cmn_init_counter() after all DTC and DTM
allocations succeed, nothing actually needs cleaning up in this case
anyway, and it should just return directly as it did before.

Fixes: 7633ec2c ("perf/arm-cmn: Rework DTC counters (again)")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/ed589c0d8e4130dc68b8ad1625226d28bdc185d4.1702322847.git.robin.murphy@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

Parsing and ignoring 'nokaslr' can be done from anywhere, except from
the code that runs very early and is therefore built with limitations on
the kind of relocations it is permitted to use.

So move it to a source file that is part of the ordinary kernel build.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20231129111555.3594833-63-ardb@google.comSigned-off-by: Will Deacon <will@kernel.org>

All ID register value overrides are =0 with the exception of the nokaslr
pseudo feature which uses =1. In order to remove the dependency on
kstrtou64(), which is part of the core kernel and no longer usable once
we move idreg-override into the early mini C runtime, let's just parse a
single hex digit (with optional leading 0x) and set the output value
accordingly.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20231129111555.3594833-62-ardb@google.comSigned-off-by: Will Deacon <will@kernel.org>