memory_map_top_down(9)

💖 NAME 💖

memory_map_top_down — maps the range [map_start, map_end) top down, bestie. That's it, that's the whole vibe ✨

So yes, this is a page straight out of the Kernel API Manual, and we're about to get into it 🫶

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🌸 SYNOPSIS 🌸

void memory_map_top_down (unsigned long map_start , unsigned long map_end );

Like… that's the whole call. Two args, no return, no drama 💅

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🎀 ARGUMENTS 🎀

• map_start — the start address of the target memory range. Where the party begins 🎉
• map_end — the end address of the target memory range. Where it wraps up 🏁

Heads up: the range is [map_start, map_end) — square bracket on the left, round bracket on the right, meaning map_start is in and map_end is not. Classic half-open moment, iykyk 💀

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🦋 DESCRIPTION 🦋

Okay so here's the tea 🍓 — this function sets up the direct mapping for the memory range [map_start, map_end), and it does it in top-down order.

That said: the page tables get allocated at the end of the memory, and we map the memory top-down. No cap, that's literally how it goes 👑

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🌈 SEE ALSO 🌈

• The kernel file ./arch/x86/mm/init.c 📁
• memory_map_bottom_up(9) — the other direction bestie, go say hi 🫶

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and that's the whole page!! 💜 This iconic little number comes from ./arch/x86/mm, dated October 2026, and honestly? memory_map_top_down(9) ate and left no crumbs 💅🎀✨