firmware_map_add_early(9)

🦋 firmware_map_add_early(9) 🦋

okay so welcome to the Kernel API Manual, bestie — today’s main character is firmware_map_add_early(9), and the vibes are extremely bootmem.

✨ NAME ✨

firmware_map_add_early — adds a firmware mapping entry. periodt.

🌸 SYNOPSIS 🌸

int firmware_map_add_early (u64 start , u64 end , const char *type );

💅 ARGUMENTS 💅

• start — start of the memory range. the opening scene, the “once upon a time” of this range.
• end — end of the memory range. the closing credits, the “that’s a wrap” of this range.
• type — type of the memory range. the little label on the memory-range outfit.

🫶 DESCRIPTION 🫶

Adds a firmware mapping entry. This function uses the bootmem allocator for memory allocation. no cap.

⚠️ okay so the timeline is strict, bestie: that function must be called before late_initcall. not after, not “whenever you get around to it” — before. 💀

🔥 RETURN 🔥

0 on success, or -ENOMEM if no memory could be allocated. so if it slays, you get 0; if memory is giving absolutely nothing, you get -ENOMEM. 😭

👑 SEE ALSO 👑

Kernel file ./drivers/firmware/memmap.c, plus the whole squad:

• firmware_map_add_entry(9)
• firmware_map_remove_entry(9)
• firmware_map_find_entry_in_list(9)
• firmware_map_find_entry(9)
• firmware_map_find_entry_bootmem(9)
• firmware_map_add_hotplug(9)
• firmware_map_remove(9)

that’s the whole page, bestie 🎀 — source/version hood is ./drivers/firmware, and the date on this iconic drop is October 2026. mwah 💋