imr_fixup_memmap(9)

💅 imr_fixup_memmap — Kernel API Manual, bestie edition 🎀

okay so real talk, this one's from the Kernel API Manual and it's genuinely iconic if you're messing with Galileo-era Intel Quark stuff. buckle up 🦋

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✨ NAME ✨

imr_fixup_memmap — tearing down the IMRs that bootup set up, no cap 💅

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🌸 SYNOPSIS 🌸

void imr_fixup_memmap (struct imr_device *idev );

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🫶 ARGUMENTS 🫶

• idev — literally just a pointer to an imr_device structure. that's it. that's the whole argument. slay 💖

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🔥 DESCRIPTION 🔥

okay so here's the situation 👑 — BIOS and Grub both go ahead and set up IMRs around compressed kernel and initrd memory, right? and those IMRs need to be removed before the kernel hands out one of those IMR-encased addresses to a downstream DMA agent — think stuff like the SD or Ethernet. 🧚

and here's the part where it gets real: IMRs on Galileo are set up to immediately reset the system on violation 💀 like, no warning, no vibe check, just boom.

so as a result? if you're running a root filesystem from SD, you need the boot-time IMRs torn down — otherwise you'll be seeing seemingly random resets while you're just out here using your filesystem 😭 and you'll be like "why is my board like this" and the answer is the IMRs, bestie. it's always the IMRs. periodt.

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🌈 SEE ALSO 🌈

• the kernel file ./arch/x86/platform/intel-quark/imr.c — go read it, iykyk 📖
• imr_is_enabled(9)
• imr_read(9)
• imr_write(9)
• imr_dbgfs_state_show(9)
• imr_debugfs_register(9)
• imr_check_params(9)
• imr_raw_size(9)
• imr_address_overlap(9)
• imr_add_range(9)
• __imr_remove_range(9)
• imr_remove_range(9)
• imr_clear(9)
• imr_init(9)

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⭐ fr fr read the whole friend group, they all connect. it's giving "found family" energy 🫶

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okay that's the whole page, bestie 💜 shoutout to ./arch/x86/platform/intel-quark for housing this icon, to the October 2026 date stamp, and to imr_fixup_memmap(9) itself — main character energy, honestly. mwah 🎀💅✨