Skip to content

L
linux-davinci
Switch branch/tag
  1. 02 Sep, 2009 1 commit
  3. 31 Aug, 2009 6 commits
  5. 28 Aug, 2009 21 commits
  7. 27 Aug, 2009 6 commits
    • Benjamin Herrenschmidt's avatar
      Merge commit 'kumar/next' into next · 3c2ee2d9
      Benjamin Herrenschmidt authored
      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
      Merge commit 'origin/master' into next · f480fe39
      Benjamin Herrenschmidt authored
      f480fe39
  9. 26 Aug, 2009 5 commits
  11. 25 Aug, 2009 1 commit
    • David S. Miller's avatar
      sparc64: Validate linear D-TLB misses. · d8ed1d43
      David S. Miller authored 
      When page alloc debugging is not enabled, we essentially accept any
virtual address for linear kernel TLB misses.  But with kgdb, kernel
address probing, and other facilities we can try to access arbitrary
crap.

So, make sure the address we miss on will translate to physical memory
that actually exists.

In order to make this work we have to embed the valid address bitmap
into the kernel image.  And in order to make that less expensive we
make an adjustment, in that the max physical memory address is
decreased to "1 << 41", even on the chips that support a 42-bit
physical address space.  We can do this because bit 41 indicates
"I/O space" and thus covers non-memory ranges.

The result of this is that:

1) kpte_linear_bitmap shrinks from 2K to 1K in size

2) we need 64K more for the valid address bitmap

We can't let the valid address bitmap be dynamically allocated
once we start using it to validate TLB misses, otherwise we have
crazy issues to deal with wrt. recursive TLB misses and such.

If we're in a TLB miss it could be the deepest trap level that's legal
inside of the cpu.  So if we TLB miss referencing the bitmap, the cpu
will be out of trap levels and enter RED state.

To guard against out-of-range accesses to the bitmap, we have to check
to make sure no bits in the physical address above bit 40 are set.  We
could export and use last_valid_pfn for this check, but that's just an
unnecessary extra memory reference.

On the plus side of all this, since we load all of these translations
into the special 4MB mapping TSB, and we check the TSB first for TLB
misses, there should be absolutely no real cost for these new checks
in the TLB miss path.

Reported-by: heyongli@gmail.com
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d8ed1d43