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    • Benjamin Herrenschmidt's avatar
      [PATCH] ppc32: Tell userland about lack of standard TB · d8e998c5
      Benjamin Herrenschmidt authored
      
      
      Glibc is about to get some new high precision timer stuff that relies on
      the standard timebase of the PPC architecture.
      
      However, some (rare & old) CPUs do not have such timebase and it is a
      bit annoying to have your stuff just crash because you are running on
      the wrong CPU...
      
      This exposes to userland a CPU feature bit that tells that the current
      processor doesn't have a standard timebase.  It's negative logic so that
      glibc will still "just work" on older kernels (it will just be unhappy
      on those old CPUs but that doesn't really matter as distro tend to
      update glibc & kernel at the same time).
      
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      d8e998c5
    • Benjamin Herrenschmidt's avatar
      [PATCH] ppc32: Fix timekeeping · cbd27b8c
      Benjamin Herrenschmidt authored
      
      
      Interestingly enough, ppc32 had broken timekeeping for ages...  It
      worked, but probably drifted a bit more than could be explained by the
      actual bad precision of the timebase calibration.  We discovered that
      recently when somebody figured out that the common code was using
      CLOCK_TICK_RATE to correct the timekeeing, and ppc32 had a completely
      bogus value for it.
      
      This patch turns it into something saner.  Probably not as good as doing
      something based on the actual timebase frequency precision but I'll
      leave that sort of math to others.  This at least makes it better for
      the common HZ values.
      
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      cbd27b8c