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  1. 01 Oct, 2007 6 commits
  3. 29 Sep, 2007 4 commits
    • Jan Lübbe's avatar
      fix console change race exposed by CFS · a64314e6
      Jan Lübbe authored 
      The new behaviour of CFS exposes a race which occurs if a switch is
requested when vt_mode.mode is VT_PROCESS.

The process with vc->vt_pid is signaled before vc->vt_newvt is set.
This causes the switch to fail when triggered by the monitoing process
because the target is still -1.

[ If the signal sending fails, the subsequent "reset_vc(vc)" will then
  reset vt_newvt to -1, so this works for that case too.   - Linus ]
Signed-off-by: default avatarJan Lübbe <jluebbe@lasnet.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a64314e6
    • Linus Torvalds's avatar
      Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6 · ed7fdff5
      Linus Torvalds authored 
      * 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6:
  mv643xx_eth: Check ETH_INT_CAUSE_STATE bit
      ed7fdff5
    • Nick Piggin's avatar
      i386: remove bogus comment about memory barrier · 4827bbb0
      Nick Piggin authored 
      The comment being removed by this patch is incorrect and misleading.

In the following situation:

	1. load  ...
	2. store 1 -> X
	3. wmb
	4. rmb
	5. load  a <- Y
	6. store ...

4 will only ensure ordering of 1 with 5.
3 will only ensure ordering of 2 with 6.

Further, a CPU with strictly in-order stores will still only provide that
2 and 6 are ordered (effectively, it is the same as a weakly ordered CPU
with wmb after every store).

In all cases, 5 may still be executed before 2 is visible to other CPUs!

The additional piece of the puzzle that mb() provides is the store/load
ordering, which fundamentally cannot be achieved with any combination of
rmb()s and wmb()s.

This can be an unexpected result if one expected any sort of global ordering
guarantee to barriers (eg. that the barriers themselves are sequentially
consistent with other types of barriers).  However sfence or lfence barriers
need only provide an ordering partial ordering of memory operations -- Consider
that wmb may be implemented as nothing more than inserting a special barrier
entry in the store queue, or, in the case of x86, it can be a noop as the store
queue is in order. And an rmb may be implemented as a directive to prevent
subsequent loads only so long as their are no previous outstanding loads (while
there could be stores still in store queues).

I can actually see the occasional load/store being reordered around lfence on
my core2. That doesn't prove my above assertions, but it does show the comment
is wrong (unless my program is -- can send it out by request).

So:
   mb() and smp_mb() always have and always will require a full mfence
   or lock prefixed instruction on x86.  And we should remove this comment.
Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Cc: Paul McKenney <paulmck@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4827bbb0
    • Dale Farnsworth's avatar
      mv643xx_eth: Check ETH_INT_CAUSE_STATE bit · 2bcff60f
      Dale Farnsworth authored 
      Commit 468d09f8 masked the "state"
interrupt (bit 20 of the cause register). This results in Radstone's
PPC7D repeatedly re-entering the interrupt routine, locking up the
board. The following patch returns the required handling for this
interrupt.
Signed-off-by: default avatarMartyn Welch <martyn.welch@radstone.co.uk>
Signed-off-by: default avatarDale Farnsworth <dale@farnsworth.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
      2bcff60f
  5. 28 Sep, 2007 24 commits
  7. 27 Sep, 2007 3 commits
  9. 26 Sep, 2007 3 commits
    • Linus Torvalds's avatar
      Revert "[PATCH] x86-64: fix x86_64-mm-sched-clock-share" · ff0ce684
      Linus Torvalds authored 
      This reverts commit 184c44d2.

As noted by Dave Jones:
   "Linus, please revert the above cset.  It doesn't seem to be
    necessary (it was added to fix a miscompile in 'make allnoconfig'
    which doesn't seem to be repeatable with it reverted) and actively
   breaks the ARM SA1100 framebuffer driver."
Requested-by: default avatarDave Jones <davej@redhat.com>
Cc: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ff0ce684
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup · a07921bc
      Linus Torvalds authored 
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup:
  [x86 setup] Handle case of improperly terminated E820 chain
      a07921bc
    • Linus Torvalds's avatar
      Revert "x86-64: Disable local APIC timer use on AMD systems with C1E" · f7f847b0
      Linus Torvalds authored 
      This reverts commit e66485d7, since
Rafael Wysocki noticed that the change only works for his in -mm, not in
mainline (and that both "noapictimer" _and_ "apicmaintimer" are broken
on his hardware, but that's apparently not a regression, just a symptom
of the same issue that causes the automatic apic timer disable to not
work).

It turns out that it really doesn't work correctly on x86-64, since
x86-64 doesn't use the generic clock events for timers yet.

Thanks to Rafal for testing, and here's the ugly details on x86-64 as
per Thomas:

  "I just looked into the code and the logic vs.  noapictimer on SMP is
   completely broken.

   On i386 the noapictimer option not only disables the local APIC
   timer, it also registers the CPUs for broadcasting via IPI on SMP
   systems.

   The x86-64 code uses the broadcast only when the local apic timer is
   active, i.e.  "noapictimer" is not on the command line.  This defeats
   the whole purpose of "noapictimer".  It should be there to make boxen
   work, where the local APIC timer actually has a hardware problem,
   e.g.  the nx6325.

   The current implementation of x86_64 only fixes the ACPI c-states
   related problem where the APIC timer stops in C3(2), nothing else.

   On nx6325 and other AMD X2 equipped systems which have the C1E
   enabled we run into the following:

   PIT keeps jiffies (and the system) running, but the local APIC timer
   interrupts can get out of sync due to this C1E effect.

   I don't think this is a critical problem, but it is wrong
   nevertheless.

   I think it's safe to revert the C1E patch and postpone the fix to the
   clock events conversion."

On further reflection, Thomas noted:

   "It's even worse than I thought on the first check:

    "noapictimer" on the command line of an SMP box prevents _ONLY_ the
    boot CPU apic timer from being used.  But the secondary CPU is still
    unconditionally setting up the APIC timer and uses the non
    calibrated variable calibration_result, which is of course 0, to
    setup the APIC timer.  Wreckage guaranteed."

so we'll just have to wait for the x86 merge to hopefully fix this up
for x86-64.
Tested-and-requested-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f7f847b0
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