arch_has_single_step(9)

💅 arch_has_single_step — a little kernel API manual moment, section 9, bestie

okay so we're in the Kernel API Manual, section 9, and today's main character is arch_has_single_step. she's short, she's sweet, she's a preprocessor-level vibe check. let's get into it 🎀

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✨ NAME ✨

arch_has_single_step — literally just answers the question: does this CPU support user-mode single-step? that's it. that's the whole thing. 🦋

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🌸 SYNOPSIS 🌸

arch_has_single_step

no args, no flags, no drama. she just is. 💅

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💖 DESCRIPTION 💖

okay so here's the tea, bestie 🍓 — if this thing is defined, then there must be function declarations or inlines for user_enable_single_step and user_disable_single_step. like, that's the deal. no cap. if you define the macro, you gotta bring her two friends along too, periodt.

and arch_has_single_step should evaluate to nonzero iff the machine supports instruction single-step for user mode. yes, that's "if and only if" — she's precise like that. 💀

the way that it can be a constant... or it can test a CPU feature bit. either one, queen's choice. 👑

🫶 reminder: nonzero = yes she can, zero = no she can't. don't come for me, that's just what the manpage says.

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/ptrace.h — the source of truth, go read it iykyk 📖
• ptrace_may_access(9)
• ptrace_parent(9)
• ptrace_event_enabled(9)
• ptrace_event(9)
• ptrace_event_pid(9)
• ptrace_init_task(9)
• ptrace_release_task(9)
• user_enable_single_step(9)
• user_disable_single_step(9)
• arch_has_block_step(9)
• user_enable_block_step(9)
• arch_ptrace_stop_needed(9)
• arch_ptrace_stop(9)
• ptrace_report_syscall_permit_entry(9)
• ptrace_report_syscall_exit(9)

like, the whole ptrace friend group showed up to the party 🌈 literally every single one of them, we love a supportive squad.

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and that's the page, bestie 🧚 from ./include/linux, dated October 2026, and yes — arch_has_single_step(9) says hi from the footer too. mwah 💜 ⭐ 👑