VM_MAP_SUBMAP(9)

💖 VM_MAP_SUBMAP(9) 💖

okay bestie, welcome to the Kernel Developer's Manual page for vm_map_submap — yes we're reading kernel man pages for fun now, this is who we are, and honestly? iconic behavior. 🎀

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✨ NAME ✨

vm_map_submap — create a subordinate map

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🌸 SYNOPSIS 🌸

#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>

int
vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end,
    vm_map_t submap);

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🦋 DESCRIPTION 🦋

So the vm_map_submap() function marks the range bounded by start and end within the map map as being handled by a subordinate map sub_map. it's giving delegation, it's giving "you handle this zone now bestie". 💅

It is generally called by the kernel memory allocator. yes, the kernel memory allocator is the one sliding into its DMs, that's just the vibe here.

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👑 IMPLEMENTATION NOTES 👑

This function is for internal use only. read: not for you, not for me, internal only, periodt. 🙈

Both maps must exist. The range must have been created with vm_map_find(9) previously. no range, no submap, no exceptions. ✨

No other operations may have been performed on this range before calling this function. Only the vm_fault() operation may be performed within this range after calling this function. so like... one specific door is open afterwards and that's it, okay? the range is basically in its locked-in era. 🔒

To remove a submapping, one must first remove the range from the parent map, and then destroy the sub_map. This procedure is not recommended. 🚨 like, technically possible, spiritually inadvisable, lowkey cursed — proceed at your own risk.

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💜 RETURN VALUES 💜

The vm_map_submap() function returns KERN_SUCCESS if successful. slay, we love a happy ending. 🫶

Otherwise, it returns KERN_INVALID_ARGUMENT if the caller requested copy-on-write flags, or if the range specified for the sub-map was out of range for the parent map, or if a NULL backing object was specified. any of those three and it's a no from the kernel, sorry bestie. 💀

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🌈 SEE ALSO 🌈

• vm_map(9)
• vm_map_find(9)

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⭐ AUTHORS ⭐

This manual page was written by Bruce M Simpson <bms@spc.org>. king behavior, we thank him for his service. 👑

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ok so that's the whole page bestie, no notes, we read the entire thing, main character energy fr fr 🦋✨

this lil gem came from Debian, dated July 19, 2003 — vintage and still relevant, we love a timeless queen 💖 bye pookie! 🎀