Skip to content

L
linux-davinci
Switch branch/tag
  1. 03 Jul, 2008 10 commits
  3. 02 Jul, 2008 8 commits
  5. 01 Jul, 2008 5 commits
    • Tim Yamin's avatar
      powerpc/mpc5200: Fix lite5200b suspend/resume · 18d76ac9
      Tim Yamin authored 
      Suspend/resume ("echo mem > /sys/power/state") does not work with
vanilla kernels -- the system does not suspend correctly and just
hangs. This patch fixes this so suspend/resume works:

1) of_iomap does not map the whole 0xC000 of the MPC5200 immr so
saving registers does not work.
2) PCI registers need to be saved and restored.
Signed-off-by: default avatarTim Yamin <plasm@roo.me.uk>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      18d76ac9
    • John Linn's avatar
      powerpc/legacy_serial: Bail if reg-offset/shift properties are present · 1e6d1f26
      John Linn authored 
      The legacy serial driver does not work with an 8250 type UART that is
described in the device tree with the reg-offset and reg-shift
properties.  This change makes legacy_serial ignore these devices.
Signed-off-by: default avatarJohn Linn <john.linn@xilinx.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      1e6d1f26
    • John Linn's avatar
      powerpc/bootwrapper: update for initrd with simpleImage · 5d1a0411
      John Linn authored 
      This change to the makefile corrects the build of a simpleImage with initrd.
Signed-off-by: default avatarJohn Linn <john.linn@xilinx>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      5d1a0411
    • Gautham R Shenoy's avatar
      rcu: fix hotplug vs rcu race · 8558f8f8
      Gautham R Shenoy authored 
      Dhaval Giani reported this warning during cpu hotplug stress-tests:

| On running kernel compiles in parallel with cpu hotplug:
|
| WARNING: at arch/x86/kernel/smp.c:118
| native_smp_send_reschedule+0x21/0x36()
| Modules linked in:
| Pid: 27483, comm: cc1 Not tainted 2.6.26-rc7 #1
| [...]
|  [<c0110355>] native_smp_send_reschedule+0x21/0x36
|  [<c014fe8f>] force_quiescent_state+0x47/0x57
|  [<c014fef0>] call_rcu+0x51/0x6d
|  [<c01713b3>] __fput+0x130/0x158
|  [<c0171231>] fput+0x17/0x19
|  [<c016fd99>] filp_close+0x4d/0x57
|  [<c016fdff>] sys_close+0x5c/0x97

IMHO the warning is a spurious one.

cpu_online_map is updated by the _cpu_down() using stop_machine_run().
Since force_quiescent_state is invoked from irqs disabled section,
stop_machine_run() won't be executing while a cpu is executing
force_quiescent_state(). Hence the cpu_online_map is stable while we're
in the irq disabled section.

However, a cpu might have been offlined _just_ before we disabled irqs
while entering force_quiescent_state(). And rcu subsystem might not yet
have handled the CPU_DEAD notification, leading to the offlined cpu's
bit being set in the rcp->cpumask.

Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent sending
smp_reschedule() to an offlined CPU.

Here's the timeline:

CPU_A						 CPU_B
--------------------------------------------------------------
cpu_down():					.
.					   	.
.						.
stop_machine(): /* disables preemption,		.
		 * and irqs */			.
.						.
.						.
take_cpu_down();				.
.						.
.						.
.						.
cpu_disable(); /*this removes cpu 		.
		*from cpu_online_map 		.
		*/				.
.						.
.						.
restart_machine(); /* enables irqs */		.
------WINDOW DURING WHICH rcp->cpumask is stale ---------------
.						call_rcu();
.						/* disables irqs here */
.						.force_quiescent_state();
.CPU_DEAD:					.for_each_cpu(rcp->cpumask)
.						.   smp_send_reschedule();
.						.
.						.   WARN_ON() for offlined CPU!
.
.
.
rcu_cpu_notify:
.
-------- WINDOW ENDS ------------------------------------------
rcu_offline_cpu() /* Which calls cpu_quiet()
		   * which removes
		   * cpu from rcp->cpumask.
		   */

If a new batch was started just before calling stop_machine_run(), the
"tobe-offlined" cpu is still present in rcp-cpumask.

During a cpu-offline, from take_cpu_down(), we queue an rt-prio idle
task as the next task to be picked by the scheduler. We also call
cpu_disable() which will disable any further interrupts and remove the
cpu's bit from the cpu_online_map.

Once the stop_machine_run() successfully calls take_cpu_down(), it calls
schedule(). That's the last time a schedule is called on the offlined
cpu, and hence the last time when rdp->passed_quiesc will be set to 1
through rcu_qsctr_inc().

But the cpu_quiet() will be on this cpu will be called only when the
next RCU_SOFTIRQ occurs on this CPU. So at this time, the offlined CPU
is still set in rcp->cpumask.

Now coming back to the idle_task which truely offlines the CPU, it does
check for a pending RCU and raises the softirq, since it will find
rdp->passed_quiesc to be 0 in this case. However, since the cpu is
offline I am not sure if the softirq will trigger on the CPU.

Even if it doesn't the rcu_offline_cpu() will find that rcp->completed
is not the same as rcp->cur, which means that our cpu could be holding
up the grace period progression. Hence we call cpu_quiet() and move
ahead.

But because of the window explained in the timeline, we could still have
a call_rcu() before the RCU subsystem executes it's CPU_DEAD
notification, and we send smp_send_reschedule() to offlined cpu while
trying to force the quiescent states. The appended patch adds comments
and prevents checking for offlined cpu everytime.

cpu_online_map is updated by the _cpu_down() using stop_machine_run().
Since force_quiescent_state is invoked from irqs disabled section,
stop_machine_run() won't be executing while a cpu is executing
force_quiescent_state(). Hence the cpu_online_map is stable while we're
in the irq disabled section.
Reported-by: default avatarDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: default avatarGautham R Shenoy <ego@in.ibm.com>
Acked-by: default avatarDhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8558f8f8
    • Thomas Gleixner's avatar
      x86: fix NODES_SHIFT Kconfig range · efac4189
      Thomas Gleixner authored 
      commit 43238382
       x86: change size of node ids from u8 to s16

set the range for NODES_SHIFT to 1..15.

The possible range is 1..9

Fixes Bugzilla #10726
Reported-by: default avatarDave Jones <davej@codemonkey.org.uk>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      efac4189
  7. 30 Jun, 2008 14 commits
  9. 29 Jun, 2008 3 commits