RTPatchForPowerPC

Introduction (New)
This patch is to fix build breakage and boot/runtime errors/warnings for PowerPC (esp. 64 bit architecture).


 * It fixes build breakage on arch/powerpc with realtime preempt patch. This applies on top of linux-2.6.20 and patch-2.6.20-rt8. Although there has been some efforts to port realtime-preempt patch to powerpc, build breakage still exists for powerpc (esp. 64bit architecture).


 * It also fixes boot and runntime errors/warnings for powerpc (esp. 64 bit).

Compile and boot tested on celleb (Cell Reference set) for both　PREEMPT_RT=y and PREEMPT_NONE=y.

CONFIG_MCOUNT, CONFIG_EVENT_TRACE and other tracing options nor　CONFIG_GENERIC_TIME, clockevents etc have not yet been supported.

Comments and suggestions are welcome.

PS. These patches were also sent to linuxppc-dev and lkml. see. http://ozlabs.org/pipermail/linuxppc-dev/2007-March/032640.html, http://lkml.org/lkml/2007/3/6/503, http://ozlabs.org/pipermail/linuxppc-dev/2007-March/032648.html and http://lkml.org/lkml/2007/3/6/505.

Patch
It's here attachment:2.6.20-rt8-v0.1.patch

How to use
This applies to linux-2.6.20 kernel with realtime preempt patch (patch-2.6.20-rt8) by Ingo Molnar at http://people.redhat.com/mingo/realtime-preempt/.

This patch are provided under GNU GPL.

Future work

 * tracing options support.
 * Generic time, clockevents support
 * Measurements
 * etc. etc...

March 6, 2007 (C) TOSHIBA Corporation.

Introduction (RT patch for 2.6.16 kernel)
This series of patches adds support to make rt patch work on powerpc64 targets. Currently two platforms (powermac and cell) are tested.

These patches apply to 2.6.16 kernel with realtime preempt patch (patch-2.6.16-rt17) by Ingo Molnar at http://people.redhat.com/mingo/realtime-preempt/.

Compile tested for both powermac and cell w/ and w/o PREEMPT_RT.

Boot tested for powermac w/ and w/o PREEMPT_RT on a Dual Power Mac G5. (boot on initrd and CONFIG_BLK_DEV_IDE_PMAC is disabled (or with a work around included in the patch) for PREEMPT_RT, see *1).

Boot tested for cell w/ and w/o PREEMPT_RT on the systemsim simulator provided by IBM. Note that "iommu=off" command line option is applied.

These patches are provided under GNU GPL.

Review, comments and suggestions are welcome.

Best regards, Tsutomu OWA (tsutomu.owa ( at ) toshiba dot co dot jp


 * 1: There seem to be some flaw(s) which makes some devices unavailable (namely cdrom drive and SATA drive so far) when PREEMPT_HARDIRQS is enabled. "hda: lost interrupt" and/or "ata1: command 0x50 host_stat 0x4" show up.  Other devices such as network, keyboard etc. seem to work fine.  I've looked into this for a couple of weeks in vain.

How To Use
Apply patches to 2.6.16 kernel with realtime preempt patch (patch-2.6.16-rt17). patch-2.6.16-rt29 is also tested with the additional rt29-v0.1-do_irq.patch listed above.

Future Work
Here is a list of things that could be worked on for these patches:
 * Fix ide cdrom: "hda: lost interrupt"
 * Fix SCSI SATA: "ata1: command 0x25 timeout, stat 0x50 host_stat 0x4"
 * Port to the latest realtime preempt patch.
 * etc...

7/25/2006 (C) TOSHIBA Corporation.