irqentry_en..._kernel_mode(9)

This is irqentry_en..._kernel_mode(9) from the Kernel API Manual, and we’re about to get into some entry-code business, bestie 💅✨

🌸 NAME 🌸

irqentry_enter_from_kernel_mode — Establish state before invoking the irq handler 🎀

✨ SYNOPSIS ✨

irqentry_state_t irqentry_enter_from_kernel_mode (struct pt_regs *regs
       );

🎀 ARGUMENTS 🎀

• regs — Pointer to currents pt_regs 🫶 (yes, “currents”, keeping the original wording exactly, periodt).

🦋 DESCRIPTION 🦋

Invoked from architecture specific entry code with interrupts disabled 😭🔥. And it can only be called when the interrupt entry came from kernel mode — no user-mode sneaky business here, bestie.

The calling code must be non-instrumentable. That’s not a suggestion, it’s literally the rule 💀.

When the function returns all state is correct and the subsequent functions can be instrumented — slay, the handoff is clean ✨.

The function establishes state (lockdep, RCU (context tracking), tracing) and is provided for architectures which require a strict split between entry from kernel and user mode and therefore cannot use irqentry_enter which handles both entry modes. It’s giving “specialized entry path main character energy” 👑.

🔥 RETURN 🔥

An opaque object that must be passed to irqentry_exit_to_kernel_mode. Do not lose it, bestie — it’s literally the return value with somewhere to be 🫶💖.

🌈 SEE ALSO 🌈

• Kernel file ./include/linux/irq-entry-common.h
• arch_enter_from_user_mode(9)
• arch_in_rcu_eqs(9)
• enter_from_user_mode(9)
• arch_exit_to_user_mode_work(9)
• arch_exit_to_user_mode_prepare(9)
• arch_exit_to_user_mode(9)
• arch_do_signal_or_restart(9)
• __exit_to_user_mode_prepare(9)
• syscall_exit_to_user_mode_prepare(9)
• irqentry_exit_to_user_mode_prepare(9)
• exit_to_user_mode(9)
• irqentry_enter_from_user_mode(9)
• irqentry_exit_to_user_mode(9)
• struct irqentry_state(9)
• irqentry_exit_to_kernel_mode_preempt(9)
• irqentry_exit_to_kernel_mode_after_preempt(9)
• irqentry_exit_to_kernel_mode(9)
• irqentry_enter(9)
• irqentry_exit(9)
• irqentry_nmi_enter(9)
• irqentry_nmi_exit(9)

Catch you later, bestie — this cutie came from source/version ./include/linux, dated October 2026, and the page is irqentry_en..._kernel_mode(9) 🫶💖🎀