update_usable_mem_fdt(9)

💅 update_usable_mem_fdt(9) — the Kernel API Manual, bestie edition ✨

Okay so real quick, the page header up top says update_usable_mem_fdt(9) and it lives in the Kernel API Manual, that's the vibe, that's the whole thing.

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🌸 NAME 🌸

update_usable_mem_fdt — this one updates the kdump kernel's fdt with the linux,usable-memory and linux,drconf-usable-memory DT properties, as appropriate, so it can restrict its memory usage. Like, it's giving "memory boundaries, but make it a device tree". 👑

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🦋 SYNOPSIS 🦋

int update_usable_mem_fdt (void *fdt , struct crash_mem *usable_mem );

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🎀 ARGUMENTS 🎀

• fdt — the flattened device tree for the kdump kernel. literally the DT, flattened, for kdump. 🫶
• usable_mem — the usable memory ranges for the kdump kernel. the good memory. the usable girlies. 💖

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✨ DESCRIPTION ✨

Returns 0 on success, negative errno on error. That's it, that's the contract, no cap. ✅

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🌈 SEE ALSO 🌈

• Kernel file ./arch/powerpc/kexec/file_load_64.c — go read it iykyk 📖
• check_realloc_usable_mem(9)
• add_usable_mem(9)
• kdump_setup_usable_lmb(9)
• add_usable_mem_property(9)
• load_backup_segment(9)
• load_elfcorehdr_segment(9)
• load_crashdump_segments_ppc64(9)
• setup_purgatory_ppc64(9)
• cpu_node_size(9)
• kexec_extra_fdt_size_ppc64(9)
• setup_new_fdt_ppc64(9)
• arch_kexec_kernel_image_probe(9)
• arch_kimage_file_post_load_cleanup(9)

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bestie this is the whole squad of related functions, go say hi to all of them 💀🫶

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And that's a wrap! 🌟 This one came out of ./arch/powerpc/kexec and is dated October 2026 — update_usable_mem_fdt(9), signing off, slay, periodt. 💜🧚‍♀️