Major changes in upstream Linux kernel for ARC cores

It is important to note that ARC-port of the Linux kernel is an essential part of upstream projects which means: a) ARC port benefits from all the fixes and improvements that were done across the entire source tree like new device drivers, file-systems or even brand new subsystems, as well as fixes for existing code b) All ARC-specific changes are introduced in new kernel releases and only fixes that conform to so-called "stable kernel" rules are back-ported to older kernel versions. That said major changes in existing ARC code or any new features we add in arch/arc/ won't ever be back-ported to upstream stable releases.

Lengthy changelogs for entire source tree (not only ARC-related) could be found here: https://kernelnewbies.org/LinuxVersions. Given above note about ARC port we strongly recommend to take generic changes into account as serious as ARC-only changes.

4.16

• MCIP (ARConnect): Minor improvements

4.15

• Added support for ARC HS48 cores (MMUv5)
• Perf: Clean-up and micro-optimizations
• HSDK: Switch DisplayLink driver from FBDEV to DRM version

4.14, LTS - projected EOL Jan, 2020

• Platforms
  • HSDK: Added initial support
  • AXS10x: Switch to CLK driver
  • NPS400: Fixes and improvements

4.13

• PAE40
  • Fixes
  • Prepare AXS103 for use of PAE40

4.12

• ARCv2
  • Implement regional operations for L1 data- and instruction caches

4.11

• ARCv2
  • Save accumulator regs (r58, r59) if present
  • IDU INTC: Fixes and improvements
• Read CPU clock value from CLK driver
• VDK: Add support of MMC and UIO

4.10

• ARC: Move ARC Timers to clocksource
• IRQ: Minor improvements
• ARCompact
  • Fix unaligned access handler
  • Accommodate 4-color aliased data cache
• ARCv2
  • Clean-up of MCIP (ARConnect) code
  • Fixes and improvements for IO-Coherency
  • Re-enable IO-Coherency by default
  • Save user-space r30 on kernel entry
  • GFRC, RTC fixes and improvements
• Platforms
  • AXS10X: Enable ARC PGU as kernel module by default
  • NPS400: Support hardware scheduling
  • Rename ZEBU platform to HAPS

4.9, LTS - projected EOL Jan, 2019

• IRQ: Minor improvements
• DMA: Implement arch-specific dma_map_ops.mmap
• Bootlog improvements
• Syscall for kernel-aasisted atomic operations
• Dwarf2 unwinder refactoring (switch from .debug_frame to .eh_frame)
• Enable generic "cache-references" and "cache-misses" events in perf for ARC
• ARCv2
  • IOC: Disable by default
  • Support 64-bit atomic ops
• Platforms
  • NPS400: Minor improvements
  • NSIM: Support perf events with interrupts
  • ZEBU: Add support of emulation platform

4.8

• ARCv2
  • Support ABIv4
• Platforms
  • VDK, NSIMOSCI: Enable ARC PGU

4.7

• ARC Timers refactoring
• Support for reserved memory defined by device tree
• Platforms
  • AXS10x: Add support of ARC PGU
  • NPS400: Add new platform

4.6

• Enable LOCKDEP
• DMA: Support DMA to/from memory beyond 4Gb
• PCI: Add support in ARC architecture
• Platforms
  • NSIMOSCI: Use NPS_ENET driver for Ethernet controller

4.5

• DMA: Convert ARC to dma_map_ops
• ARCv2
  • MCIP (ARConnect): IPI Cross-core interrupts fixes and improvements
  • Introduce MMU Super Page Size support (2 and 16MB)

4.4, LTS - projected EOL Feb, 2022

• UNWINDER: Dwarf2 fixes and improvements
• ARCv2
  • Add PAE40 support
  • Add HIGHMEM support
  • Add Transparent Huge Pages support

4.3

• ARCv2
  • Improvements for perf (support of SMP, overflow IRQs, user-/kernel-mode selection)
  • Initial support of IO-Coherency

4.2

• ARCv2
  • Introduced initial port for ARCv2 ISA