copy_to_user_fromio(9)

💅 copy_to_user_fromio(9) 💅

okay bestie, welcome to the copy_to_user_fromio page — it's a section 9 (Kernel API Manual) moment, and honestly? kind of iconic. it's giving "kernel internals but make it cute." let's get into it ✨

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🎀 NAME 🎀

copy_to_user_fromio — copy data from mmio-space to user-space. that's it. that's the whole vibe. short, sweet, slays. 🦋

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✨ SYNOPSIS ✨

int copy_to_user_fromio (void __user *dst , const volatile void __iomem
*src , size_t count );

so it hands you back an int, and it takes three things. literally three. keep up bestie 🫶

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🌸 ARGUMENTS 🌸

• dst — the destination pointer, and it lives on user-space. void __user * energy. that's where the data's going, periodt. 💖
• src — the source pointer, chillin' on mmio. note the const volatile void __iomem * — yes, both const and volatile, she contains multitudes. 🌈
• count — the data size to copy, in bytes. how much we're moving. that's the number. 🔢

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⭐ DESCRIPTION ⭐

Copies the data from mmio-space to user-space. that's the whole thing — mmio in, user-space out, no cap. it does exactly what the name says, which honestly is such a serve. 💅

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🔥 RETURN 🔥

• Zero if successful 🎉
• non-zero on failure 😭 (so like, check it. please. for me.)

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🦋 SEE ALSO 🦋

• Kernel file ./sound/core/memory.c — the whole squad lives there 🏠
• copy_to_iter_fromio(9)
• copy_from_user_toio(9)
• copy_from_iter_toio(9)

the friend group fr fr. go read them next, iykyk 👑

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and that's the page!! this cute lil doc comes from ./sound/core and it's dated October 2026 — so yeah, it's from the future, main character energy only 💜🎀✨ ngl you ate that read bestie, go forth and copy responsibly 🍓🧚