generic_access_phys(9)

📦 version 7.3.1, in nixpkgs unstable

💅 generic_access_phys — kernel API manual, bestie edition ✨

okay so this is a page from the Kernel API Manual, and honestly? it's a little niche but it's lowkey iconic. it's all about generic_access_phys 🎀

✨ NAME ✨

generic_access_phys — the generic implementation for iomem mmap access 🫶

🌸 SYNOPSIS 🌸

int generic_access_phys (struct vm_area_struct *vma , unsigned long addr
, void *buf , int len , int write );

that's the whole signature, no cap 💅

🦋 ARGUMENTS 🦋

  • vma — the vma you're accessing, like the actual one, not a vibe ✨
  • addr — a userspace address. and hear me say this: NOT a relative offset within vma. do not come for me with an offset, i will know 🙈
  • buf — the buffer where you read from / write to 🍓
  • len — how long the transfer is, in case you were wondering 📏
  • write — set this to FOLL_WRITE when you're writing; any other case means you're reading 💜

🔥 DESCRIPTION 🔥

So the way that this works is: it's a generic implementation for vm_operations_struct.access for an iomem mapping. periodt.

This callback gets used by access_process_vm when the vma is not page based. iykyk 💅

🌈 SEE ALSO 🌈

okay this list is LONG but we do not skip, we do not summarise, we list every single one because that's the assignment 👑

Kernel file ./mm/memory.c — and then, in order:

like, thirty-six of them?? she ate and left no crumbs 😭🔥

ok that's the whole page bestie, no gatekeeping, nothing skipped 💖

and finally, the cute little sign-off: this beauty lives in the ./mm source, the manual is the Kernel API Manual, and it's dated October 2026 ⭐ go forth and access your iomem safely, mwah 🧚💜

📦 where this page comes from