PAPR_SYSPARM_IOC_GET(9)

✨ PAPR_SYSPARM_IOC_GET ✨

kernel api manual, but make it bestie-friendly 🎀 — yes we're reading a section 9 page together, hold my iced coffee 🧚

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💖 NAME 💖

PAPR_SYSPARM_IOC_GET — the ioctl that goes and fetches the value of a PAPR system parameter for you. that's it, that's the whole vibe 🦋

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🌸 SYNOPSIS 🌸

PAPR_SYSPARM_IOC_GET

literally just the one thing, no arguments to memorize, we love a low-maintenance icon 👑

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🦋 DESCRIPTION 🦋

okay so first thing you're gonna notice: this bad boy uses _IOWR and you might be like "girl why is it read and write??" and the answer is one corner case 💅

pulling the value of the "OS Service Entitlement Status" parameter (60) needs the caller to actually supply input data — a date string — in the buffer that gets passed to firmware. so yeah, it writes to you but it also needs a lil something from you first. give and take, healthy relationship 🫶

because of that, the length and data of the incoming papr_sysparm_io_block are always used to initialize the work area that gets handed to ibm,get-system-parameter. always always. no skipping.

now, no other parameters are known to take input this way — none, zero, nada — so in the normal everyday case, callers are encouraged (but not required) to zero-initialize length and data. encouraged bestie, not forced. it's giving polite suggestion energy 🌈

⚠️ real talk though: on error the contents of the ioblock are indeterminate. like, unknown. do not trust them. do not build a personality around them. 💀

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🔥 RETURN 🔥

here's your vibe check on what comes back:

• 0 — success, slay 🎉 and length is the length of valid data in data, and it will not exceed PAPR_SYSPARM_MAX_OUTPUT.
• -EIO — platform error. (-1) 😭
• -EINVAL — incorrect data length or format. (-9999) 🙈
• -EPERM — the calling partition is not allowed to access this parameter. (-9002) like, security said no 🚫
• -EOPNOTSUPP — parameter not supported on this platform. (-3) wrong platform, wrong era, moving on ✨

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🎀 SEE ALSO 🎀

• kernel file ./arch/powerpc/include/uapi/asm/papr-sysparm.h — go read it, iykyk 📖
• PAPR_SYSPARM_IOC_SET(9) — the setter sibling, the other main character 👑

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and that's the whole page, bestie!! 🌸 this gem lives in ./arch/powerpc/include/uapi/asm, stamped October 2026 — no cap, go get those system parameters 💖✨🦋💅