git: kernel - Add workaround for errata #721 on AMD cpus (found by Matt Dillon)

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>]

commit afea4d5a3cf396976e5b778f8477d972e8c29735
Author: Matthew Dillon <dillon@apollo.backplane.com>
Date:   Fri Mar 23 15:49:54 2012 -0700

    kernel - Add workaround for errata #721 on AMD cpus (found by Matt Dillon)
    
    * Official reference for errata 721:
    
        http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
    
    * This is the cpu bug found by Matthew Dillon, present on all K10 cores
      (so far).  AMD has indicated that the bug is not present on Bulldozer
      cpus.
    
    * The MSR workaround is now reported and programmed during kernel boot.
    
    * No discernable difference in performance was detected running GCC
      with and without the MSR adjustment.
    
    * Verified to have fixed our test case w/GCC.  It no longer seg-faults.

Summary of changes:
 sys/platform/pc64/x86_64/initcpu.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/afea4d5a3cf396976e5b778f8477d972e8c29735


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