Linux 5.6 Release - Main Changes, Arm, MIPS & RISC-V Architectures

Linus Torvalds has just announced the release of Linux 5.6 on the Linux Kernel Mailing List:

So I’ll admit to vacillating between doing this 5.6 release and doing another -rc.

This has a bit more changes than I’d like, but they are mostly from davem’s networking fixes pulls, and David feels comfy with them. And I looked over the diff, and none of it looks scary. It’s just slightly more than I’d have preferred at this stage – not doesn’t really seem worth delaying a release over.

So about half the diff from the final week is network driver fixlets,
and some minor core networking fixes. Another 20% is tooling – mostly bpf and netfilter selftests (but also some perf work).

The rest is “misc” – mostly random drivers (gpio, rdma, input) and DTS files. With a smattering of fixes elsewhere (a couple of afs fixes, some vm fixes, etc).

The shortlog is appended, nothing really looks all that exciting, and
most of the discussions I’ve seen are already about things for the
next merge window.

Which obviously opens now as of the release, and I’ll start doing pulls tomorrow. I already have a couple of pull requests in pending in my inbox – thank you.

And while I haven’t really seen any real sign of kernel development being impacted by all the coronavirus activity – I suspect a lot of us work from home even normally, and my daughter laughed at me and called me a “social distancing champ” the other day – it may be worth just mentioning: I think we’re all reading the news and slightly distracted. I’m currently going by the assumption that we’ll have a fairly normal 5.7 release, and there doesn’t seem to be any signs saying otherwise, but hey, people may have better-than-usual reasons for missing the merge window. Let me know if you know of some subsystem that ends up being affected.

So we’ll play it by ear and see what happens. It’s not like the merge window is more important than your health, or the health of people around you.

Linus

Released in January, Linux 5.5 improved io_uring asynchronous I/Os and WiFi, added support for KUnit unit testing framework for the Linux kernel, and SMB rootfs and multichannel support, among other changes.

Linux 5.6 has some newsworthy changes including:

USB4 support – The Thunderbolt specification has morphed into USB4 and the kernel configuration options for Thunderbolt have been renamed accordingly.
WireGuard VPN (Virtual Private Network) is now part of Linux 5.6 networking stack
Preliminary support for the first-generation Amazon Echo
The Linux kernel is now year-2038 ready as all users of the 32-bit time_t type have been fixed.

Some notable changes related to Arm architecture:

Allwinner
- Allwinner A10 – CSI (BT656 and Parallel)
- Allwinner A64 – MIPI DSI, DVFS
- Allwinner A64 / A83T / H3 / H5 / H6 – Thermal
- Allwinner H6 – PWM
- Allwinner H3 / H5 / H6 / R40 – PMU
- Allwinner R40 – CSI (BT656 and Parallel) and SPI
- New Devices – Libre Computer ALL-H3-IT, PineH64 Model A, Emlid Neutis SoM (H3 variant)
Rockchip
- Media – Staging driver for Rockchip MIPI Synopsys DPHY RX0
- DRM – Add support for PX30
- Ethernet (not only Amlogic) – RTL8211F Rx/Tx delay configuration tested on ODROID-C1 and Khadas VIM2
- New boards – Radxa Dalang Carrier (supports rk3288 and rk3399 SOMs), Radxa Rock Pi N10 (RK3399Pro) and VMARC RK3399Pro SOM found on the board
Amlogic
- Clock drivers – Add Amlogic meson8b DDR clock controller and input clocks to Amlogic meson8b controllers; some fixed for mali clock and pll driver
- Media – Amlogic SM1 adds support for MPEG1 and MPEG2 decoders
- DRM – Added driver for the ARM Framebuffer Compression decoders found in the Amlogic GXM and G12A SoCs
- New boards – Libretech Amlogic GX PC (s905d and s912-based variants); Videostrong KII Pro
Samsung
- Switch from legacy to atomic pwm API in rx1950 (s3c24xx),
- Defconfig changes
  - Bring back explicitly wanted options which were removed through
    make savedefconfig. savedefconfig removes options selected by
    other symbols, however developers of this other symbol can remove
    anytime ‘select’ statement.
  - Enable NFS v4.1 and v4.2, useful in testing/CI systems.
  - Enable thermal throttling through devfreq framework.
- DTS Updates
  1. Couple ARM and wcore bus regulators on Exynos542x so higher
    frequencies could be used with dynamic voltage and frequency scaling.
    Enable these higher frequencies.
  2. Correct the polarity of USB3503 hub GPIOs.
  3. Adjust the bus frequencies (scaled with devfreq framework) on Exynos5422 Odroid boards to match values possible to obtain from root PLLs.
  4. Add display to Tiny4412 board.
  5. Cleanups and minor improvements.
Qualcomm
- Added support for Qualcomm SC7180 (8-core 64bit SoC, unnamed CPU class)
- Driver updates:
  - SCM major refactoring and cleanup
  - Properly flag active only power domains as active only
  - Add SC7180 and SM8150 RPMH power domains
  - Return EPROBE_DEFER from QMI if packet family is not yet available
- DTS updates:
  - Add SAW L2 nodes to boot secondary cpus on IPQ40xx
  - Fix remaining IRQ_TYPE_NONE on APQ8084
  - Update tsens node to new style
  - Add modem remoteproc node to MSM8974
  - Move ADSP SMD edge into ADSP remoteproc node for MSM8974
  - Add and enable wireless communication subsystem on MSM8974 and Fairphone 2
  - Add MSM8974 interconnect provider nodes
  - Add MSM8974 OCMEM node
- DTS ARM64 updates:
  - Align SDM845 firmware paths with linux-firmware
  - Make WiFi work on Dragonboard845c
  - Wire up wakeup controller for SDM845
  - Critical thermal interrupt support for SDM845, MSM8996 and MSM8998
  - SM8150 – Enable UFS, add remoteproc enablers and nodes, add CPUfreq, add RPMH power-domain node
  - Cleanup and refactor MSM8996 dts structure
  - MS8996 – Increase core voltage, fix USB phy settings
  - MSM8998 – Add missing alias for BLSP UART in MTP, add remoteproc nodes for ADSP, modem and sensor core, enable WiFI
  - Add CPUfreq, QUPs, USB, remoteproc etc for SC7180
  - Enable USB OTG for Dragonboard 410c
  - Add vibrator motor node for PM8916
  - Properly specify APCS clocks for MSM8916
  - Add CPR and HFPLL for QCS404
  - Enable full CPUfreq (with AVS) for QCS404
- Defconfig updates:
  - Enable NVMEM and OSM CPUfreq drivers
  - Enable CPR driver
  - Enable HFPLL driver
  - Enable ATH10k SNOC driver
  - Enable PMIC thermal driver
  - Enable wakeup controller driver
  - Enable watchdog driver
  - Enable PRNG driver
  - Enable SN65DSI86 DSI to DisplayPort bridge driver
  - Enable QCA Bluetooth driver
  - Enable Qualcomm SoCinfo driver
  - Enable SPI and QSPI drivers
  - Enable drivers providing remoteproc dependencies
  - Enable anx78xx HDMI bridge driver
  - Enable MSM8974 interconnect provider driver
- New Boards – Inforce 6640 Single Board Computer (msm8996-based) and SC7180 IDP (SC7180-based) development board
MediaTek
- ASoC – Add MediaTek MT6660 Speaker Amp Driver
- USB – support for MediaTek musb controller in
  host, peripheral and otg mode
Other new Arm hardware platforms and SoCs:
- Atmel/Microchip – SAM9X60 ARM926 SoC; Kizboxmini, sam9x60 EK, sama5d27 Wireless SOM (wlsom1)
- Marvell – Armada 385-based SolidRun Clearfog GTR
- NXP – Gateworks GW59xx boards based on i.MX6/6Q/6QDL, Tolino Shine 3 eBook reader (i.MX6sl), Embedded Artists COM (i.MX7ULP), SolidRun Clearfog CX/ITX and HoneyComb (LX2160A-based systems), Google Coral Edge TPU (i.MX8MQ)
- ST Ericsson – ab8505 (variant of ab8500) and db8520 (variant of
  db8500) SoCs; Samsung Galaxy S III mini (GT-I8190), HREF520 reference board for DB8520
- STMicro – STM32MP15 SoCs (1-2 Cortex-A7, CAN, GPU depending on SKU), and reference boards
- Texas Instruments – OMAP 37xx gets split into AM3703/AM3715/DM3725, which are all variants of it with different GPU/media IP configurations. Gen1 Amazon Echo (OMAP3630-based)
- UNISOC – SC9863A SoC (8x Cortex-A55 mobile chipset w/ GPU, modem)

MIPS Linux 5.6 changelog:

Support mremap() for the VDSO, primarily to allow CRIU to restore
the VDSO to its checkpointed location.
Restore the MIPS32 cBPF JIT, after having reverted the enablement
of the eBPF JIT for MIPS32 systems in the 5.5 cycle.
Improve cop0 counter synchronization behavior whilst onlining CPUs
by running with interrupts disabled.
Better match FPU behavior when emulating multiply-accumulate
instructions on pre-r6 systems that implement IEEE754-2008 style
MACs.
Loongson64 kernels now build using the MIPS64r2 ISA, allowing them
to take advantage of instructions introduced by r2.
Support for the Ingenic X1000 SoC & the really nice little CU Neo
development board that’s using it.
Support for WMAC on GARDENA Smart Gateway devices.
Lots of cleanup & refactoring of SGI IP27 (Origin 2*) support in
preparation for introducing IP35 (Origin 3*) support.
Various Kconfig & Makefile cleanups

Changes for RISC-V architecture in Linux 5.6:

Support for KASAN (KernelAddressSANitizer)
32-bit physical addresses on rv32i-based systems
Support for CONFIG_DEBUG_VIRTUAL
DT entry for the FU540 GPIO controller, which has recently had a device driver merged
A series of Kconfig updates to ease selecting the drivers necessary
to run on QEMU’s virt platform.
DTS updates for SiFive’s HiFive Unleashed.

Some of those changes are said to allow booting a buildroot-based system on QEMU’s virt board.

For the full list of commit messages, you can check out the changelog generated with the command git log v5.5..v5.6 --stat. KernelNewbies website should also soon have a Linux 5.6 changelog.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.