[Bug 1096323] [NEW] valgrind claims to support 3dnow! in cpuid, but doesn't

[Bradley Baetz]

Public bug reported:

See https://bugs.kde.org/show_bug.cgi?id=291568 - on AMD CPUs, valgrind
exposes a cpuid that shows 3dnow support, however valgrind doesn't
actually support those instructions.

This results in IR decoding errors when using valgrind on ffmpeg-related
apps (in my case, mythtv).

I get:

vex amd64->IR: unhandled instruction bytes: 0xF 0xF 0xC1 0xBF 0xF 0xF
0xD3 0xBF

(In this case, this is the PAVGUSB instruction)

The "fix" is in https://bugs.kde.org/show_bug.cgi?id=291568, which masks
out the appropriate CPUID bit so that 3dnow isn't claimed as present. A
bit hackish, but since its upstream....

Ubuntu 12.04, valgrind 1:3.7.0-0ubuntu3

** Affects: valgrind
     Importance: Unknown
         Status: Unknown

** Affects: valgrind (Ubuntu)
     Importance: Undecided
         Status: New

** Bug watch added: KDE Bug Tracking System #291568
   https://bugs.kde.org/show_bug.cgi?id=291568

** Also affects: valgrind via
   https://bugs.kde.org/show_bug.cgi?id=291568
   Importance: Unknown
       Status: Unknown

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https://bugs.launchpad.net/bugs/1096323

Title:
  valgrind claims to support 3dnow! in cpuid, but doesn't

Status in Valgrind:
  Unknown
Status in “valgrind” package in Ubuntu:
  New

Bug description:
  See https://bugs.kde.org/show_bug.cgi?id=291568 - on AMD CPUs,
  valgrind exposes a cpuid that shows 3dnow support, however valgrind
  doesn't actually support those instructions.

  This results in IR decoding errors when using valgrind on ffmpeg-
  related apps (in my case, mythtv).

  I get:

  vex amd64->IR: unhandled instruction bytes: 0xF 0xF 0xC1 0xBF 0xF 0xF
  0xD3 0xBF

  (In this case, this is the PAVGUSB instruction)

  The "fix" is in https://bugs.kde.org/show_bug.cgi?id=291568, which
  masks out the appropriate CPUID bit so that 3dnow isn't claimed as
  present. A bit hackish, but since its upstream....

  Ubuntu 12.04, valgrind 1:3.7.0-0ubuntu3

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