linux.git/include/linux/entry-common.h, branch v7.1-rc2

entry: Kill ARCH_SYSCALL_WORK_{ENTER,EXIT}

2026-04-16T20:19:29+00:00

Nowadays nothing redefines these flags.

Signed-off-by: Oleg Nesterov 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Jinjie Ruan 
Link: https://patch.msgid.link/advfWWKgOQkFkwp9@redhat.com

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2026-04-14T23:48:56+00:00

Pull arm64 updates from Catalin Marinas:
 "The biggest changes are MPAM enablement in drivers/resctrl and new PMU
  support under drivers/perf.

  On the core side, FEAT_LSUI lets futex atomic operations with EL0
  permissions, avoiding PAN toggling.

  The rest is mostly TLB invalidation refactoring, further generic entry
  work, sysreg updates and a few fixes.

  Core features:

   - Add support for FEAT_LSUI, allowing futex atomic operations without
     toggling Privileged Access Never (PAN)

   - Further refactor the arm64 exception handling code towards the
     generic entry infrastructure

   - Optimise __READ_ONCE() with CONFIG_LTO=y and allow alias analysis
     through it

  Memory management:

   - Refactor the arm64 TLB invalidation API and implementation for
     better control over barrier placement and level-hinted invalidation

   - Enable batched TLB flushes during memory hot-unplug

   - Fix rodata=full block mapping support for realm guests (when
     BBML2_NOABORT is available)

  Perf and PMU:

   - Add support for a whole bunch of system PMUs featured in NVIDIA's
     Tegra410 SoC (cspmu extensions for the fabric and PCIe, new drivers
     for CPU/C2C memory latency PMUs)

   - Clean up iomem resource handling in the Arm CMN driver

   - Fix signedness handling of AA64DFR0.{PMUVer,PerfMon}

  MPAM (Memory Partitioning And Monitoring):

   - Add architecture context-switch and hiding of the feature from KVM

   - Add interface to allow MPAM to be exposed to user-space using
     resctrl

   - Add errata workaround for some existing platforms

   - Add documentation for using MPAM and what shape of platforms can
     use resctrl

  Miscellaneous:

   - Check DAIF (and PMR, where relevant) at task-switch time

   - Skip TFSR_EL1 checks and barriers in synchronous MTE tag check mode
     (only relevant to asynchronous or asymmetric tag check modes)

   - Remove a duplicate allocation in the kexec code

   - Remove redundant save/restore of SCS SP on entry to/from EL0

   - Generate the KERNEL_HWCAP_ definitions from the arm64 hwcap
     descriptions

   - Add kselftest coverage for cmpbr_sigill()

   - Update sysreg definitions"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (109 commits)
  arm64: rsi: use linear-map alias for realm config buffer
  arm64: Kconfig: fix duplicate word in CMDLINE help text
  arm64: mte: Skip TFSR_EL1 checks and barriers in synchronous tag check mode
  arm64/sysreg: Update ID_AA64SMFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ZFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64FPFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ISAR2_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ISAR0_EL1 description to DDI0601 2025-12
  arm64/hwcap: Generate the KERNEL_HWCAP_ definitions for the hwcaps
  arm64: kexec: Remove duplicate allocation for trans_pgd
  ACPI: AGDI: fix missing newline in error message
  arm64: Check DAIF (and PMR) at task-switch time
  arm64: entry: Use split preemption logic
  arm64: entry: Use irqentry_{enter_from,exit_to}_kernel_mode()
  arm64: entry: Consistently prefix arm64-specific wrappers
  arm64: entry: Don't preempt with SError or Debug masked
  entry: Split preemption from irqentry_exit_to_kernel_mode()
  entry: Split kernel mode logic from irqentry_{enter,exit}()
  entry: Move irqentry_enter() prototype later
  entry: Remove local_irq_{enable,disable}_exit_to_user()
  ...

entry: Remove local_irq_{enable,disable}_exit_to_user()

2026-04-08T09:43:31+00:00

local_irq_enable_exit_to_user() and local_irq_disable_exit_to_user() are
never overridden by architecture code, and are always equivalent to
local_irq_enable() and local_irq_disable().

These functions were added on the assumption that arm64 would override
them to manage 'DAIF' exception masking, as described by Thomas Gleixner
in these threads:

  https://lore.kernel.org/all/20190919150809.340471236@linutronix.de/
  https://lore.kernel.org/all/alpine.DEB.2.21.1910240119090.1852@nanos.tec.linutronix.de/

In practice arm64 did not need to override either. Prior to moving to
the generic irqentry code, arm64's management of DAIF was reworked in
commit:

  97d935faacde ("arm64: Unmask Debug + SError in do_notify_resume()")

Since that commit, arm64 only masks interrupts during the 'prepare' step
when returning to user mode, and masks other DAIF exceptions later.
Within arm64_exit_to_user_mode(), the arm64 entry code is as follows:

	local_irq_disable();
	exit_to_user_mode_prepare_legacy(regs);
	local_daif_mask();
	mte_check_tfsr_exit();
	exit_to_user_mode();

Remove the unnecessary local_irq_enable_exit_to_user() and
local_irq_disable_exit_to_user() functions.

Signed-off-by: Mark Rutland 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Jinjie Ruan 
Acked-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20260407131650.3813777-3-mark.rutland@arm.com

entry: Add missing kernel-doc for arch_ptrace_report_syscall functions

2026-03-24T22:06:33+00:00

Document @regs and @step parameters for arch_ptrace_report_syscall_entry()
and arch_ptrace_report_syscall_exit() that were missing from the kernel-doc
comments.

Signed-off-by: Kit Dallege 
Signed-off-by: Thomas Gleixner 
Assisted-by: Claude:claude-opus-4-6
Link: https://patch.msgid.link/20260315170941.65913-1-xaum.io@gmail.com

Merge branch 'core/entry' into sched/core

2026-01-30T14:40:05+00:00

Pull the entry update to avoid merge conflicts with the time slice
extension changes.

Signed-off-by: Thomas Gleixner

entry: Inline syscall_exit_work() and syscall_trace_enter()

2026-01-30T14:38:10+00:00

After switching ARM64 to the generic entry code, a syscall_exit_work()
appeared as a profiling hotspot because it is not inlined.

Inlining both syscall_trace_enter() and syscall_exit_work() provides a
performance gain when any of the work items is enabled. With audit enabled
this results in a ~4% performance gain for perf bench basic syscall on
a kunpeng920 system:

    | Metric     | Baseline    | Inlined     | Change  |
    | ---------- | ----------- | ----------- | ------  |
    | Total time | 2.353 [sec] | 2.264 [sec] |  ↓3.8%  |
    | usecs/op   | 0.235374    | 0.226472    |  ↓3.8%  |
    | ops/sec    | 4,248,588   | 4,415,554   |  ↑3.9%  |

Small gains can be observed on x86 as well, though the generated code
optimizes for the work case, which is counterproductive for high
performance scenarios where such entry/exit work is usually avoided.

Avoid this by marking the work check in syscall_enter_from_user_mode_work()
unlikely, which is what the corresponding check in the exit path does
already.

[ tglx: Massage changelog and add the unlikely() ]

Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260128031934.3906955-14-ruanjinjie@huawei.com

entry: Add arch_ptrace_report_syscall_entry/exit()

2026-01-30T14:38:09+00:00

ARM64 requires a architecture specific ptrace wrapper as it needs to save
and restore scratch registers.

Provide arch_ptrace_report_syscall_entry/exit() wrappers which fall back to
ptrace_report_syscall_entry/exit() if the architecture does not provide
them.

No functional change intended.

[ tglx: Massaged changelog and comments ]

Suggested-by: Mark Rutland 
Suggested-by: Thomas Gleixner 
Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Brodsky 
Link: https://patch.msgid.link/20260128031934.3906955-11-ruanjinjie@huawei.com

entry: Rework syscall_exit_to_user_mode_work() for architecture reuse

2026-01-30T14:38:09+00:00

syscall_exit_to_user_mode_work() invokes local_irq_disable_exit_to_user()
and syscall_exit_to_user_mode_prepare() after handling pending syscall exit
work.

The conversion of ARM64 to the generic entry code requires this to be split
up, so move the invocations of local_irq_disable_exit_to_user() and
syscall_exit_to_user_mode_prepare() into the only caller.

No functional change intended.

[ tglx: Massaged changelog and comments ]

Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Brodsky 
Reviewed-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260128031934.3906955-10-ruanjinjie@huawei.com

entry: Remove unused syscall argument from syscall_trace_enter()

2026-01-30T14:38:09+00:00

The 'syscall' argument of syscall_trace_enter() is immediately overwritten
before any real use and serves only as a local variable, so drop the
parameter.

No functional change intended.

Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260128031934.3906955-2-ruanjinjie@huawei.com

rseq: Implement syscall entry work for time slice extensions

2026-01-22T10:11:18+00:00

The kernel sets SYSCALL_WORK_RSEQ_SLICE when it grants a time slice
extension. This allows to handle the rseq_slice_yield() syscall, which is
used by user space to relinquish the CPU after finishing the critical
section for which it requested an extension.

In case the kernel state is still GRANTED, the kernel resets both kernel
and user space state with a set of sanity checks. If the kernel state is
already cleared, then this raced against the timer or some other interrupt
and just clears the work bit.

Doing it in syscall entry work allows to catch misbehaving user space,
which issues an arbitrary syscall, i.e. not rseq_slice_yield(), from the
critical section. Contrary to the initial strict requirement to use
rseq_slice_yield() arbitrary syscalls are not considered a violation of the
ABI contract anymore to allow onion architecture applications, which cannot
control the code inside a critical section, to utilize this as well.

If the code detects inconsistent user space that result in a SIGSEGV for
the application.

If the grant was still active and the task was not preempted yet, the work
code reschedules immediately before continuing through the syscall.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251215155709.005777059@linutronix.de