linux-drivers/
drivers/char/hw_random

Hardware Random Number Generator (hwrng) subsystem and drivers

A collection of drivers for hardware random number generators built into CPUs, chipsets, embedded SoCs, TPM-like security blocks, and virtual machine paravirtual devices. They feed entropy to the kernel and expose /dev/hwrng for userspace, covering everything from Intel and AMD CPU RNGs to ARM SoC TRNGs from Mediatek, Renesas, TI, and others, plus the virtio-rng device used by QEMU/KVM guests.

keep conf=0.95 deploy=high replacement=none subsystem=char category=crypto
95%

recommendation

It should stay because this is an actively maintained umbrella subsystem rather than a single legacy driver, and hardware RNGs remain essential for both new embedded SoCs and virtual machines. Recent 2026 patch traffic adds support for current Mediatek and Renesas RZ/N1D parts and fixes virtio-rng for guests, showing healthy upstream development. Effectively every modern Linux deployment, from phones to cloud VMs, depends on something in this directory for entropy.

repository signals

53 files
12,581 source lines
258 commits, 5y
+4,182 / −1,657 lines added / removed, 5y
96 authors, 5y
monthly commits · 2021-04-21 → 2026-04-21 · 258 total · active in 55/61 months
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sources

  1. lore.kernel.org

    April 2026 feature work adds Mediatek hwrng support via SMCCC, showing active upstream development for current SoCs.

  2. lore.kernel.org

    April 2026 virtio-rng bugfix traffic shows the subsystem is still maintained for virtualized deployments.

  3. lore.kernel.org

    March 2026 enablement for Renesas RZ/N1D through the omap hwrng path indicates continuing use on shipping embedded platforms.

  4. kernel.org

    The Linux hw_random framework exposes /dev/hwrng and supports multiple hardware-specific RNG drivers through one core subsystem.

  5. qemu.org

    QEMU recommends virtio devices for virtual machines, supporting the case that virtio-rng remains relevant in new VM deployments.

codex reasoning notes (technical)

Recommendation is keep: this directory is an active umbrella subsystem, not a dead single-chip driver. Local Kconfig inspection shows many current and legacy backends plus virtio/optee/platform drivers. Lore evidence was gathered with lore_regex on patch diffs for drivers/char/hw_random and shows fresh 2026 feature and bugfix traffic; no removal evidence was found, and an attempted lei query for removal/deprecation discussion failed due local sandboxed lei socket startup. Kernel hw_random and QEMU virtio URLs were obtained via web search. Deployment remains high because new embedded SoCs and VMs still need hardware/para-virtual RNG support.