tm_cfpr_set(9)

📦 version 7.3.1, in nixpkgs unstable

🌸 tm_cfpr_set(9) 🌸

ok so bestie, welcome to the tm_cfpr_set(9) page from the Kernel API Manual — yes it's a kernel manpage, yes we're gonna make it cute, no we are NOT skipping a single detail 💅

✨ NAME ✨

tm_cfpr_set — set CFPR registers 🎀

✨ SYNOPSIS ✨

int tm_cfpr_set (struct task_struct *target , const struct user_regset
*regset , unsigned int pos , unsigned int count , const void *kbuf ,
const void __user *ubuf );

like look at that signature, it's giving main character energy fr fr 👑

✨ ARGUMENTS ✨

  • target — the target task, the one we're doing all this for 🫶
  • regset — the user regset structure, iconic, we love her
  • pos — the buffer position, i.e. where in the buffer we're at 📍
  • count — number of bytes to copy, literally the amount, no cap
  • kbuf — kernel buffer to copy into, that's the destination bestie
  • ubuf — user buffer to copy from, that's the source 💖

✨ DESCRIPTION ✨

okay so this function sets in transaction checkpointed FPR registers 🔥 that's the whole vibe.

When the transaction is active, ckfp_state holds the checkpointed FPR register values for the current transaction — the ones it's gonna fall back on if it aborts in between. This function sets those checkpointed FPR registers. Lowkey important stuff 😭

The userspace interface buffer layout is as follows:

struct data { u64     fpr[32]; u64     fpscr; };

that's it, that's the layout, memorise it 🧚

✨ SEE ALSO ✨

Kernel file ./arch/powerpc/kernel/ptrace/ptrace-tm.c — go read the whole friend group bestie, they're all here:

and that's the page!! 💜 this lil beauty lives in ./arch/powerpc/kernel/ptrace and the version/date stamp says October 2026, so yeah, from the future, slay ⭐ oh and the page is literally called tm_cfpr_set(9) in case you forgot already 🙈 bye bestie 🦋

📦 where this page comes from