QNX Technical Articles
QNX® Momentics® Development Suite 6.3.2: PPCBE procnto-600-smp for Freescale MPC8641D Patch (Patch ID 960) Release Notes
Date of this edition: May 16, 2008
Target OS: This patch is compatible with targets that are running QNX® Neutrino® 6.3.2.
Host OS: In order to apply this patch, you must have installed QNX Momentics 6.3.2 as a self-hosted QNX Neutrino system, or on one of the following host OSs:
- Microsoft Windows Vista, XP SP2, or 2000 SP4
- Linux Red Hat Enterprise Workstation 4 or 5, Red Hat Fedora Core 6 or 7, Ubuntu 6.0.6 LTS or 7.0.4, or SUSE 10
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Contents
Throughout this document, you may see reference numbers associated with particular issues, changes, etc. When corresponding with our Technical Support staff about a given issue, please quote the relevant reference number. You might also find the reference numbers useful for tracking issues as they become fixed.
What's in this patch?
This patch contains updates to the PPCBE version of the SMP kernel. You need this patch only for Freescale MPC8641D boards.
The following files are installed under $QNX_TARGET/:
- ppcbe/boot/sys/procnto-600-smp
- ppcbe/boot/sys/procnto-600-smp-instr
Fixed issues
When the kernel does a context switch, it issues a dummy stwcx. (Store Word Conditional Indexed) command to clear any outstanding reservation, as recommended for the PPC architecture. However, some processors can have issues if this stwcx. to address A occurs while the reservation is already held to a different address B.
To avoid this problem on the Freescale MPC8641D board, procnto first issues a dummy lwarx (Load Word And Reserved Indexed) command to a specific address, and then issues the dummy stwcx. to the same address.
This patch creates a system page cpuinfo flag, PPC_CPU_STWCX_BUG, to indicate which CPUs are affected and, on those processors, adds the dummy lwarx to the context switch code. (Ref# 45538)
Known issues
None currently known.
Technical support
If you have any questions, comments, or problems with a QNX product, please contact Technical Support. For more information, see the How to Get Help chapter of the Welcome to QNX Momentics guide or visit our website, www.qnx.com.