Kernel 4.4

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Kernel downloads for the "Development stream"

Download Description
upstream kernel 4.4 kernel 4.4 - upstream with feature descriptions.
linux-4.4-s390-message-catalog.tar.gz / MD5 "Development Stream" kernel 4.4 - message-catalog (optional)

2016-04-21: kernel 4.4 - upstream (feature description)

To download the linux-4.4.tar.gz visit:

The upstream kernel 4.4 contains the following functionality developed by the Linux on z Systems development team:

The IOMMU API for PCI devices on z Systems allows to map physical memory to arbitrary virtual PCI DMA addresses, as opposed to the conventional DMA API where the DMA addresses are generated internally within the DMA mapping operations.
The IOMMU API can be used by an exploiter like the VFIO framework ("Virtual Function I/O") to allow user space access to PCI devices, for example to facilitate PCI device pass-through for QEMU/KVM.

Linux can IPL from a DASD in any subchannel set.
With this line item, users can specify an IPL device in any subchannel set. This includes: support to use a DASD from a subchannel set > 0 during the early stages of IPL and support to specify a DASD from a subchannel set > 0 to use for re-IPL.
This feature is supported on IBM zEnterprise 196 GA2 and later.
For documentation see Device Drivers, Features, and Commands, Chapter 6 'Booting Linux' and Chapter 'Remotely controlling virtual hardware - snipl'.

Enable the OSA card to perform IP/TCP/UDP check sum calculation for incoming and outgoing IP packets for layer 2.
With this feature, the qeth device driver can use the OSA-Express layer 2 receive and transmit check sum offloading capabilities that were introduced with OSA-Express 4S.
For documentation see Device Drivers, Features, and Commands, Part 4 'Networking', Chapter 15 'Qeth device driver'.

qeth does no longer make use of a given portname.
In the past an OSA-Express port name was required to identify a shared OSA port. All operating system instances that shared the port had to use the same port name. This requirement no longer applies. Even though the qeth sysfs attribute 'portname' still exists, it is no longer used. Storing a value into sysfs attribute portname is still possible, but has no effect. A deprecated message shows up once in this case. Reading the sysfs attribute portname value returns with 'no portname required'.
For documentation see Device Drivers, Features, and Commands, Chapter 16 'qeth device driver for OSA-Express (QDIO) and HiperSockets' and Chapter 56: 'Commands for Linux on z Systems', 'lsqeth - List qeth-based network devices' and 'lszdev - Display z Systems device configurations'.

Extend RSA modulus sizes for keys in CRT format in s390/zcrypt device driver.
In the past only even modulus sizes were allowed for RSA keys in CRT format. This restriction was based on limited RSA key generation on older crypto adapters that provided only even modulus sizes. This restriction is not valid any more.
For documentation see Device Drivers, Features, and Commands, Chapter 45 'Generic cryptographic device driver'.

2016-04-21: "Development Stream" kernel 4.4 message catalog (feature - optional patch)

linux-4.4-s390-message-catalog.tar.gz / MD5 ... recommended (2016-04-21)

This patch contains:

Kernel message catalog.
Add support for automatic message tags to the printk macro families dev_xyz and pr_xyz. The message tag consists of a component name and a 24 bit hash of the message text. For each message that is documented in the included kernel message catalog a man page can be created with a script (which is included in the patch). The generated man pages contain explanatory text that is intended to help understand the messages.

Note that only s390 specific messages are prepared appropriately and included in the generated message catalog.

This patch is optional as it is very unlikely to be accepted in upstream kernel, but is recommended for all distributions which are built based on the 'Development stream'.