1. 02 11月, 2011 9 次提交
  2. 15 9月, 2011 1 次提交
    • I
      um: Save FPU registers between task switches · fbfe9c84
      Ingo van Lil 提交于
      Some time ago Jeff prepared 42daba31 ("uml: stop saving process FP
      state") for UML to stop saving the process FP state between task
      switches.  The assumption was that since with SKAS0 every guest process
      runs inside a host process context the host OS will take care of keeping
      the proper FP state.
      
      Unfortunately this is not true for multi-threaded applications, where
      all guest threads share a single host process context yet all may use
      the FPU on their own.  Although I haven't verified it I suspect things
      to be even worse in SKAS3 mode where all guest processes run inside a
      single host process.
      
      The patch reintroduces the saving and restoring of the FP context
      between task switches.
      
      [richard@nod.at: Ingo posted this patch in 2009, sadly it was never applied
      and got lost. Now in 2011 the problem was reported by Gunnar.]
      Signed-off-by: NIngo van Lil <inguin@gmx.de>
      Signed-off-by: NRichard Weinberger <richard@nod.at>
      Reported-by: <gunnarlindroth@hotmail.com>
      Tested-by: <gunnarlindroth@hotmail.com>
      Cc: Stanislav Meduna <stano@meduna.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fbfe9c84
  3. 26 7月, 2011 1 次提交
  4. 23 10月, 2008 2 次提交