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  1. 28 Aug, 2009 2 commits
  2. 27 Aug, 2009 6 commits
    • Benjamin Herrenschmidt's avatar
      3c2ee2d9
    • Gautham R Shenoy's avatar
      powerpc/pseries: Reduce the polling interval in __cpu_up() · 67764263
      Gautham R Shenoy authored
      Time time taken for a single cpu online operation on a pseries machine
      is as follows:
      Dedicated LPAR (POWER6): ~220ms.
      Shared LPAR (POWER5)   : ~240ms.
      
      Of this time, approximately 200ms is taken up by __cpu_up(). This is because
      we poll every 200ms to check if the new cpu has notified it's presence
      through the cpu_callin_map. We repeat this operation until the new cpu sets
      the value in cpu_callin_map or 5 seconds elapse, whichever comes earlier.
      
      However, using completion_structs instead of polling loops,
      the time taken by the new processor to indicate it's presence has
      found to be less than 1ms on pseries. This method however may not
      work on all powerpc platforms due to the time-base synchronization code.
      
      Keeping this in mind, we could reduce msleep polling interval from
      200ms to 1ms while retaining the 5 second timeout.
      
      With this, the time taken for a cpu online operation changes as follows:
      Dedicated LPAR (POWER6): 20-25ms.
      Shared LPAR (POWER5)   : 60-80ms.
      
      In both these cases, it was found that the code polls through the loop
      only once indicating that 1ms is a reasonable value, atleast on pseries.
      
      The code needs testing on other powerpc platforms.
      Signed-off-by: default avatarGautham R Shenoy <ego@in.ibm.com>
      Acked-by: default avatarJoel Schopp <jschopp@austin.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      67764263
    • Bastian Blank's avatar
      powerpc: Remove SMP warning from PowerMac cpufreq · 6fdc31a2
      Bastian Blank authored
      On Thu, Aug 13, 2009 at 04:14:58PM +1000, Benjamin Herrenschmidt wrote:
      > On Tue, 2009-08-11 at 11:39 +0200, Bastian Blank wrote:
      > > This patch just disables this driver on SMP kernels, as it is obviously
      > > not supported.
      > Why not remove the #error instead ? :-) I don't think it's still
      > meaningful, especially since we use the timebase for delays nowadays
      > which doesn't depend on the CPU frequency...
      
      Your call. Take this one:
      
      The build of a PowerMac 32bit kernel currently fails with
      
      error: #warning "WARNING, CPUFREQ not recommended on SMP kernels"
      
      Thie patch removes the not longer applicable SMP warning from the
      PowerMac cpufreq code.
      Signed-off-by: default avatarBastian Blank <waldi@debian.org>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      6fdc31a2
    • Josh Boyer's avatar
      powerpc: Fix __flush_icache_range on 44x · 14d75752
      Josh Boyer authored
      The ptrace POKETEXT interface allows a process to modify the text pages of
      a child process being ptraced, usually to insert breakpoints via trap
      instructions.  The kernel eventually calls copy_to_user_page, which in turn
      calls __flush_icache_range to invalidate the icache lines for the child
      process.
      
      However, this function does not work on 44x due to the icache being virtually
      indexed.  This was noticed by a breakpoint being triggered after it had been
      cleared by ltrace on a 440EPx board.  The convenient solution is to do a
      flash invalidate of the icache in the __flush_icache_range function.
      Signed-off-by: default avatarJosh Boyer <jwboyer@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      14d75752
    • Benjamin Herrenschmidt's avatar
      powerpc/mm: Cleanup handling of execute permission · ea3cc330
      Benjamin Herrenschmidt authored
      This is an attempt at cleaning up a bit the way we handle execute
      permission on powerpc. _PAGE_HWEXEC is gone, _PAGE_EXEC is now only
      defined by CPUs that can do something with it, and the myriad of
      #ifdef's in the I$/D$ coherency code is reduced to 2 cases that
      hopefully should cover everything.
      
      The logic on BookE is a little bit different than what it was though
      not by much. Since now, _PAGE_EXEC will be set by the generic code
      for executable pages, we need to filter out if they are unclean and
      recover it. However, I don't expect the code to be more bloated than
      it already was in that area due to that change.
      
      I could boast that this brings proper enforcing of per-page execute
      permissions to all BookE and 40x but in fact, we've had that now for
      some time as a side effect of my previous rework in that area (and
      I didn't even know it :-) We would only enable execute permission if
      the page was cache clean and we would only cache clean it if we took
      and exec fault. Since we now enforce that the later only work if
      VM_EXEC is part of the VMA flags, we de-fact already enforce per-page
      execute permissions... Unless I missed something
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      ea3cc330
    • Benjamin Herrenschmidt's avatar
      f480fe39
  3. 26 Aug, 2009 5 commits
  4. 25 Aug, 2009 27 commits