Release Notes for HelenOS 0.8.0

HelenOS 0.8.0 (Speranza) was released on December 19, 2018.

This document contains a summary of changes made to HelenOS since release 0.7.2.

Special Notes for this Release

Features Introduced in This Release

General

We partially revived the Doxygen ​ reference documentation and plan to further improve it.

reference documentation and plan to further improve it. HelenOS abandoned the *-linux-gnu and *-unknown-elf toolchain targets in favor of its ​ own -helenos target. Utilizing the compiler-provided headers and libraries avoids a number of problems and reduces the amount of architecture-support code that otherwise needs to be provided directly in HelenOS.

Kernel

Kernel is now stored in standard ELF format

Ordered dictionary ( odict.h ) now available in kernel Container based on red-black trees Replaced AVL trees and B+trees Unlike the B+tree implementation, which was also used in HelenOS address space management, the ordered dictionary comes with an API which does not allocate memory itself and is thus more favorable from the point of view of resource management.

) now available in kernel The kernel used to pass kernel addresses of IPC phone objects (a.k.a. phone hashes) as connection identifiers to userspace. This intentional but unfortunate information leak was replaced in this release by purely user-defined labels negotiated during IPC connection setup handshake. Each connected phone now has a user-defined label and imprints this label on each IPC call which is routed through it.

In 2014 HelenOS got its own implementation of RCU (Read-Copy-Update) synchronization primitive along with a CHT (Concurrent Hash Table) data type based on RCU. Although sophisticated and interesting from the technological point of view, the RCU and CHT were mostly unused and unmaintained. We therefore decided to remove these very complex features.

The kernel waitq synchronization primitive was made available to userspace via capabilities. Consequently the userspace implementation of futexes was rewritten to use waitq's as the underlying synchronization mechanism. The custom support for futexes was removed from the kernel. One ramification of this change is that the underlying kernel object is no longer allocated lazily. This increases startup times of components that use futexes, but provides better failure modes, and better resource management possibilities in the future.

Services and Drivers

Fixed support for ISA-only PCs Was broken since 0.5.0/0.6.0 since DDF could not enumerate ISA-only PC With custom build (ia32 + CPU=486) you can run in qemu-system-i386 -M isapc

Added standard PC parallel port driver

Running HelenOS on the Ski IA-64 simulator will show console output also before the userspace driver takes over.

Naming service improvements Services now register individual interfaces with the naming service. This adds a degree of type safety, potentially allows the individual interfaces to be implemented by independent tasks and moves the code slightly closer to the full-fledged ports design. Broker services (e.g. the location service) can still register a fallback port for receiving connections to all interface types explicitly using service_register_broker() .

Intel HD Audio Added PCI IDs for Wildcat Point-LP and Broadwell-U audio controllers



GUI

Fix some display issues related to a bug in the alpha blending implementation

File Systems

fdisk can now configure mount point for a volume

can now configure mount point for a volume We can now create Ext4 (Ext2, actually) file systems

Support volume labels with Ext4

Ext4(2) is the default new file system type for fdisk

Sysinst now creates Ext4(2) to install HelenOS to

vol insert can be used to re-insert a previously ejected volume

can be used to re-insert a previously ejected volume Persistent storage / system volume Sysinst will now configure a persistent /w directory As a reminder, this can only be used to install on some ia32/amd64 configurations Tetris will now store high-score table under /w Allowing it to persist across reboots - on a system installed by sysinst



Applications

​ GZX, a ZX Spectrum emulator Experimental HelenOS support in upstream since January 2018 Now available via a harbour/package ( pkg install gzx )

GZX, a ZX Spectrum emulator ​ Ccheck, C-style checker used to check HelenOS code ported to HelenOS Available via harbour/package ( pkg install sycek )

Ccheck, C-style checker used to check HelenOS code ported to HelenOS perf is a new tool collecting several simple benchmarks perf ns_ping moved from tester ping_pong now computes average and standard deviation across multiple runs perf ping_pong IPC ping-pong benchmark using new dedicated IPC test server perf malloc1 , perf malloc2 two simple user-space memory allocator benchmarks

is a new tool collecting several simple benchmarks contacts is a trivial interactive utility to demonstrate the use of SIF

is a trivial interactive utility to demonstrate the use of SIF wavplay and modplay now accept -t <target> option to select non-default audio target

and now accept option to select non-default audio target lprint utility can be used to print a file or a short message

Libraries

libc Clean separation of fibrils and async framework The async framework defines the label stored in connected IPC phones to be the userspace address of the connection structure. Because of this, the connection lookup hash table could have been dropped entirely as each incoming call already knows the connection from the label added strtold replaced <atomic.h> with standard <stdatomic.h> replaced <sys/time.h> with standard <time.h> 'x' fopen file mode modifier from C11

SIF an API for managing structured data

Miscellaneous

Prevent endless loops when printing userspace stack traces

Eliminate use of custom linker scripts for user space code

Init data is now stored as a tar archive of gzip-compressed files

Server binaries under /srv are now in sub-directories (and /srv is no longer a search directory for commands)

are now in sub-directories (and /srv is no longer a search directory for commands) Init data can now be configured to be uncompressed (used by default on GTA02 and ski) for faster boot

Can compile with undefined behavior sanitizer in either kernel, user space or both

XCW tools used to cross-compile out-of-tree HelenOS applications received fixes and enhancements Fixed compilation on some ARM platforms Use of export dir for better integration with Coastline helenos-bld-config --install-dir useful when installing application into HelenOS workspace helenos-test rebuilds HelenOS workspace and starts emulation



Regressions in This Release

We have found the following regressions that prevent releasing the image for the respective platform:

#782 HelenOS does not boot on Raspberry Pi

#783 HelenOS does not boot on GTA02

#784 HelenOS does not boot on Dell PowerEdge 3250

Fixed Logged Bugs & Enhancements

For the list of all logged defects fixed in this release, see this report.

For the list of all logged enhancements integrated in this release, see this report.

Known Bugs