tm_cvmx_get(9)

📦 version 7.3.1, in nixpkgs unstable

okay so bestie, welcome to the tm_cvmx_get(9) page from the Kernel API Manual — yes, we're doing checkpointed VMX register lore today and it's lowkey iconic ✨💅

🌸 NAME 🌸

tm_cvmx_get — get CMVX registers. That's the name, that's the whole assignment, periodt.

✨ SYNOPSIS ✨

int tm_cvmx_get (struct task_struct *target , const struct user_regset
       *regset , struct membuf to );

Not me putting the signature in here exactly as it is, because we do not play around with prototypes 🔥

💅 ARGUMENTS 💅

  • target — the target task. Like, the task in question 👀
  • regset — the user regset structure. That's the regset, bestie.
  • to — destination of copy. It's literally where the copy goes, no cap.

🦋 DESCRIPTION 🦋

Okay so this function gets in transaction checkpointed VMX registers. Iykyk — it's giving transaction checkpoint realness, fr fr.

When the transaction is active, ckvr_state and ckvrsave hold the checkpointed values for the current transaction to fall back on if it aborts in between. The way that's such a safety-net moment: if it aborts in between, those checkpointed values are the fallback 🫶

The userspace interface buffer layout is as follows:

struct data { vector128       vr[32]; vector128       vscr; vector128
       vrsave; };

That's the layout exactly — vr[32], then vscr, then vrsave, all chilling inside struct data. Obsessed with a buffer layout that knows exactly what it is 💖

🔥 SEE ALSO 🔥

Kernel file ./arch/powerpc/kernel/ptrace/ptrace-tm.c — go read it, bestie, it's right there:

mwah 💋 this page comes from ./arch/powerpc/kernel/ptrace, dated October 2026 — signed, sealed, and slayed 🎀

📦 where this page comes from