linux-toradex.git/include/linux/entry-common.h, branch v7.0-rc6 Linux kernel for Apalis and Colibri modules Merge branch 'core/entry' into sched/core 2026-01-30T14:40:05+00:00 Thomas Gleixner tglx@kernel.org 2026-01-30T14:40:05+00:00 5c4378b7b0e1f45cf38e77db9305ee2c7bf88002 Pull the entry update to avoid merge conflicts with the time slice extension changes. Signed-off-by: Thomas Gleixner <tglx@kernel.org> 
Pull the entry update to avoid merge conflicts with the time slice
extension changes.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
entry: Inline syscall_exit_work() and syscall_trace_enter() 2026-01-30T14:38:10+00:00 Jinjie Ruan ruanjinjie@huawei.com 2026-01-28T03:19:33+00:00 31c9387d0d84bc1d643a0c30155b6d92d05c92fc 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 <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260128031934.3906955-14-ruanjinjie@huawei.com 
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 <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
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 Jinjie Ruan ruanjinjie@huawei.com 2026-01-28T03:19:30+00:00 578b21fd3ab2d9901ce40ed802e428a41a40610d 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 <mark.rutland@arm.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com> Link: https://patch.msgid.link/20260128031934.3906955-11-ruanjinjie@huawei.com 
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 <mark.rutland@arm.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
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 Jinjie Ruan ruanjinjie@huawei.com 2026-01-28T03:19:29+00:00 e1647100c22eb718e9833211722cbb78e339047c 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 <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://patch.msgid.link/20260128031934.3906955-10-ruanjinjie@huawei.com 
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 <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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 Jinjie Ruan ruanjinjie@huawei.com 2026-01-28T03:19:21+00:00 03150a9f84b328f5c724b8ed9ff8600c2d7e2d7b 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 <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260128031934.3906955-2-ruanjinjie@huawei.com 
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 <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
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 Thomas Gleixner tglx@linutronix.de 2025-12-15T16:52:19+00:00 dd0a04606937af5810e9117d343ee3792635bd3d 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 <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251215155709.005777059@linutronix.de 
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 <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155709.005777059@linutronix.de
entry: Split up exit_to_user_mode_prepare() 2025-11-04T07:35:17+00:00 Thomas Gleixner tglx@linutronix.de 2025-10-27T08:45:21+00:00 70fe25a3bc53a891f0e6184c12bd55cc524cb13b exit_to_user_mode_prepare() is used for both interrupts and syscalls, but there is extra rseq work, which is only required for in the interrupt exit case. Split up the function and provide wrappers for syscalls and interrupts, which allows to separate the rseq exit work in the next step. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084307.782234789@linutronix.de 
exit_to_user_mode_prepare() is used for both interrupts and syscalls, but
there is extra rseq work, which is only required for in the interrupt exit
case.

Split up the function and provide wrappers for syscalls and interrupts,
which allows to separate the rseq exit work in the next step.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.782234789@linutronix.de
rseq: Use static branch for syscall exit debug when GENERIC_IRQ_ENTRY=y 2025-11-04T07:33:27+00:00 Thomas Gleixner tglx@linutronix.de 2025-10-27T08:45:05+00:00 eaa9088d568c84afd72fa32dbe01833aef861d0d Make the syscall exit debug mechanism available via the static branch on architectures which utilize the generic entry code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084307.333440475@linutronix.de 
Make the syscall exit debug mechanism available via the static branch on
architectures which utilize the generic entry code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.333440475@linutronix.de
entry: Remove syscall_enter_from_user_mode_prepare() 2025-11-04T07:31:37+00:00 Thomas Gleixner tglx@linutronix.de 2025-10-27T08:44:38+00:00 54a5ab56242f96555999aaa41228f77b4a76e386 Open code the only user in the x86 syscall code and reduce the zoo of functions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084306.652839989@linutronix.de 
Open code the only user in the x86 syscall code and reduce the zoo of
functions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084306.652839989@linutronix.de
entry: Clean up header 2025-11-04T07:31:14+00:00 Thomas Gleixner tglx@linutronix.de 2025-10-27T08:44:36+00:00 5204be16790f305febbf331d0ec2cead7978b3c3 Clean up the include ordering, kernel-doc and other trivialities before making further changes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20251027084306.590338411@linutronix.de 
Clean up the include ordering, kernel-doc and other trivialities before
making further changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084306.590338411@linutronix.de