* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/intel config: Fix the APB_TIMER selection x86/mrst: Add additional debug prints for pb_keys x86/intel config: Revamp configuration to allow for Moorestown and Medfield x86/intel/scu/ipc: Match the changes in the x86 configuration x86/apb: Fix configuration constraints x86: Fix INTEL_MID silly x86/Kconfig: Cyclone-timer depends on x86-summit x86: Reduce clock calibration time during slave cpu startup x86/config: Revamp configuration for MID devices x86/sfi: Kill the IRQ as id hack
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, reboot: Fix typo in nmi reboot path x86, NMI: Add to_cpumask() to silence compile warning x86, NMI: NMI selftest depends on the local apic x86: Add stack top margin for stack overflow checking x86, NMI: NMI-selftest should handle the UP case properly x86: Fix the 32-bit stackoverflow-debug build x86, NMI: Add knob to disable using NMI IPIs to stop cpus x86, NMI: Add NMI IPI selftest x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus x86: Clean up the range of stack overflow checking x86: Panic on detection of stack overflow x86: Check stack overflow in detail
If the x2apic mode is disabled for reasons like interrupt-remapping not available etc, then we need to skip the logical cpu bringup of apic-id's >= 255. Otherwise as the platform is in xapic mode, init/startup IPI's will consider only the low 8-bits and there is a possibility of re-sending init/startup IPI's to the logical cpu that is already online. This will avoid potential reboots/unpredictable behavior etc. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/20111222014632.702932458@sbsiddha-desk.sc.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Reduce the startup time for slave cpus. Adds hooks for an arch-specific function for clock calibration. These hooks are used on x86. If a newly started cpu has the same phys_proc_id as a core already active, uses the TSC for the delay loop and has a CONSTANT_TSC, use the already-calculated value of loops_per_jiffy. This patch reduces the time required to start slave cpus on a 4096 cpu system from: 465 sec OLD 62 sec NEW This reduces boot time on a 4096p system by almost 7 minutes. Nice... Signed-off-by: Jack Steiner <steiner@sgi.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Stultz <john.stultz@linaro.org> [fix CONFIG_SMP=n build] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
The previous patch modified the stop cpus path to use NMI instead of IRQ as the way to communicate to the other cpus to shutdown. There were some concerns that various machines may have problems with using an NMI IPI. This patch creates a selftest to check if NMI is working at boot. The idea is to help catch any issues before the machine panics and we learn the hard way. Loosely based on the locking-selftest.c file, this separate file runs a couple of simple tests and reports the results. The output looks like: ... Brought up 4 CPUs ---------------- | NMI testsuite: -------------------- remote IPI: ok | local IPI: ok | -------------------- Good, all 2 testcases passed! | --------------------------------- Total of 4 processors activated (21330.61 BogoMIPS). ... Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> Cc: seiji.aguchi@hds.com Cc: vgoyal@redhat.com Cc: mjg@redhat.com Cc: tony.luck@intel.com Cc: gong.chen@intel.com Cc: satoru.moriya@hds.com Cc: avi@redhat.com Cc: Andi Kleen <andi@firstfloor.org> Link: http://lkml.kernel.org/r/1318533267-18880-3-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, smpboot: Mark the names[] array in __inquire_remote_apic() as const x86: Convert vmalloc()+memset() to vzalloc()
This array is read-only. Make it explicit by marking as const. Signed-off-by: Greg Dietsche <Gregory.Dietsche@cuw.edu> Link: http://lkml.kernel.org/r/1309482653-23648-1-git-send-email-Gregory.Dietsche@cuw.edu Signed-off-by: Ingo Molnar <mingo@elte.hu>
After a newly plugged CPU sets the cpu_online bit it enables
interrupts and goes idle. The cpu which brought up the new cpu waits
for the cpu_online bit and when it observes it, it sets the cpu_active
bit for this cpu. The cpu_active bit is the relevant one for the
scheduler to consider the cpu as a viable target.
With forced threaded interrupt handlers which imply forced threaded
softirqs we observed the following race:
cpu 0 cpu 1
bringup(cpu1);
set_cpu_online(smp_processor_id(), true);
local_irq_enable();
while (!cpu_online(cpu1));
timer_interrupt()
-> wake_up(softirq_thread_cpu1);
-> enqueue_on(softirq_thread_cpu1, cpu0);
^^^^
cpu_notify(CPU_ONLINE, cpu1);
-> sched_cpu_active(cpu1)
-> set_cpu_active((cpu1, true);
When an interrupt happens before the cpu_active bit is set by the cpu
which brought up the newly onlined cpu, then the scheduler refuses to
enqueue the woken thread which is bound to that newly onlined cpu on
that newly onlined cpu due to the not yet set cpu_active bit and
selects a fallback runqueue. Not really an expected and desirable
behaviour.
So far this has only been observed with forced hard/softirq threading,
but in theory this could happen without forced threaded hard/softirqs
as well. It's probably unobservable as it would take a massive
interrupt storm on the newly onlined cpu which causes the softirq loop
to wake up the softirq thread and an even longer delay of the cpu
which waits for the cpu_online bit.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org # 2.6.39
A logic error in mwait_play_dead() causes the kernel to use mwait even on cpus which don't support it, such as KVM virtual cpus. Introduced by: 349c004e3d31: x86: A fast way to check capabilities of the current cpu Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=36222 Reported-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Avi Kivity <avi@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1306758237-9327-1-git-send-email-avi@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6: x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param x86 idle: deprecate "no-hlt" cmdline param x86 idle APM: deprecate CONFIG_APM_CPU_IDLE x86 idle floppy: deprecate disable_hlt() x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it x86 idle: clarify AMD erratum 400 workaround idle governor: Avoid lock acquisition to read pm_qos before entering idle cpuidle: menu: fixed wrapping timers at 4.294 seconds