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2013-08-06x86, asmlinkage: Make all interrupt handlers asmlinkage / __visibleAndi Kleen
These handlers are all referenced from assembler stubs, so need to be visible. The handlers without arguments become asmlinkage, the others __visible to not force regparms(0) on x86-32. I put it all into a single patch, please let me know if you want it it split up. Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1375740170-7446-4-git-send-email-andi@firstfloor.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-07-02x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt()Seiji Aguchi
Reschedule vector tracepoints may be called in cpu idle state. This causes lockdep check warning below. The tracepoint requires rcu but for accuracy it also requires irq_enter() (tracepoints record the irq context), thus, the tracepoint interrupt handler should be calling irq_enter() and not rcu_irq_enter() (irq_enter() calls rcu_irq_enter()). So, add irq_enter/exit() to smp_trace_reschedule_interrupt() with common pre/post processing functions, smp_entering_irq() and exiting_irq() (exiting_irq() calls just irq_exit() in arch/x86/include/asm/apic.h), because these can be shared among reschedule, call_function, and call_function_single vectors. [ 50.720557] Testing event reschedule_exit: [ 50.721349] [ 50.721502] =============================== [ 50.721835] [ INFO: suspicious RCU usage. ] [ 50.722169] 3.10.0-rc6-00004-gcf910e8 #190 Not tainted [ 50.722582] ------------------------------- [ 50.722915] /c/kernel-tests/src/linux/arch/x86/include/asm/trace/irq_vectors.h:50 suspicious rcu_dereference_check() usage! [ 50.723770] [ 50.723770] other info that might help us debug this: [ 50.723770] [ 50.724385] [ 50.724385] RCU used illegally from idle CPU! [ 50.724385] rcu_scheduler_active = 1, debug_locks = 0 [ 50.725232] RCU used illegally from extended quiescent state! [ 50.725690] no locks held by swapper/0/0. [ 50.726010] [ 50.726010] stack backtrace: [...] Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/51CDCFA3.9080101@hds.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20x86, trace: Add irq vector tracepointsSeiji Aguchi
[Purpose of this patch] As Vaibhav explained in the thread below, tracepoints for irq vectors are useful. http://www.spinics.net/lists/mm-commits/msg85707.html <snip> The current interrupt traces from irq_handler_entry and irq_handler_exit provide when an interrupt is handled. They provide good data about when the system has switched to kernel space and how it affects the currently running processes. There are some IRQ vectors which trigger the system into kernel space, which are not handled in generic IRQ handlers. Tracing such events gives us the information about IRQ interaction with other system events. The trace also tells where the system is spending its time. We want to know which cores are handling interrupts and how they are affecting other processes in the system. Also, the trace provides information about when the cores are idle and which interrupts are changing that state. <snip> On the other hand, my usecase is tracing just local timer event and getting a value of instruction pointer. I suggested to add an argument local timer event to get instruction pointer before. But there is another way to get it with external module like systemtap. So, I don't need to add any argument to irq vector tracepoints now. [Patch Description] Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events. But there is an above use case to trace specific irq_vector rather than tracing all events. In this case, we are concerned about overhead due to unwanted events. So, add following tracepoints instead of introducing irq_vector_entry/exit. so that we can enable them independently. - local_timer_vector - reschedule_vector - call_function_vector - call_function_single_vector - irq_work_entry_vector - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector Also, introduce a logic switching IDT at enabling/disabling time so that a time penalty makes a zero when tracepoints are disabled. Detailed explanations are as follows. - Create trace irq handlers with entering_irq()/exiting_irq(). - Create a new IDT, trace_idt_table, at boot time by adding a logic to _set_gate(). It is just a copy of original idt table. - Register the new handlers for tracpoints to the new IDT by introducing macros to alloc_intr_gate() called at registering time of irq_vector handlers. - Add checking, whether irq vector tracing is on/off, into load_current_idt(). This has to be done below debug checking for these reasons. - Switching to debug IDT may be kicked while tracing is enabled. - On the other hands, switching to trace IDT is kicked only when debugging is disabled. In addition, the new IDT is created only when CONFIG_TRACING is enabled to avoid being used for other purposes. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org>
2013-06-20x86, trace: Introduce entering/exiting_irq()Seiji Aguchi
When implementing tracepoints in interrupt handers, if the tracepoints are simply added in the performance sensitive path of interrupt handers, it may cause potential performance problem due to the time penalty. To solve the problem, an idea is to prepare non-trace/trace irq handers and switch their IDTs at the enabling/disabling time. So, let's introduce entering_irq()/exiting_irq() for pre/post- processing of each irq handler. A way to use them is as follows. Non-trace irq handler: smp_irq_handler() { entering_irq(); /* pre-processing of this handler */ __smp_irq_handler(); /* * common logic between non-trace and trace handlers * in a vector. */ exiting_irq(); /* post-processing of this handler */ } Trace irq_handler: smp_trace_irq_handler() { entering_irq(); /* pre-processing of this handler */ trace_irq_entry(); /* tracepoint for irq entry */ __smp_irq_handler(); /* * common logic between non-trace and trace handlers * in a vector. */ trace_irq_exit(); /* tracepoint for irq exit */ exiting_irq(); /* post-processing of this handler */ } If tracepoints can place outside entering_irq()/exiting_irq() as follows, it looks cleaner. smp_trace_irq_handler() { trace_irq_entry(); smp_irq_handler(); trace_irq_exit(); } But it doesn't work. The problem is with irq_enter/exit() being called. They must be called before trace_irq_enter/exit(), because of the rcu_irq_enter() must be called before any tracepoints are used, as tracepoints use rcu to synchronize. As a possible alternative, we may be able to call irq_enter() first as follows if irq_enter() can nest. smp_trace_irq_hander() { irq_entry(); trace_irq_entry(); smp_irq_handler(); trace_irq_exit(); irq_exit(); } But it doesn't work, either. If irq_enter() is nested, it may have a time penalty because it has to check if it was already called or not. The time penalty is not desired in performance sensitive paths even if it is tiny. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org>
2012-05-14x86/reboot: Update nonmi_ipi parameterDon Zickus
Update the nonmi_ipi parameter to reflect the simple change instead of the previous complicated one. There should be less of a need to use it but there may still be corner cases on older hardware that stumble into NMI issues. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1336761675-24296-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-14x86/reboot: Use NMI to assist in shutting down if IRQ failsDon Zickus
For v3.3, I added code to use the NMI to stop other cpus in the panic case. The idea was to make sure all cpus on the system were definitely halted to help serialize the panic path to execute the rest of the code on a single cpu. The main problem it was trying to solve was how to stop a cpu that was spinning with its irqs disabled. A IPI irq would be stuck and couldn't get in there, but an NMI could. Things were great until we had another conversation about some pstore changes. Because some of the backend pstore still uses spinlocks to protect the device access, things could get ugly if a panic happened and we were stuck spinning on a lock. Now with the NMI shutting down cpus, we could assume no other cpus were running and just bust the spin lock and proceed. The counter argument was, well if you do that the backend could be in a screwed up state and you might not be able to save anything as a result. If we could have just given the cpu a little more time to finish things, we could have grabbed the spin lock cleanly and everything would have been fine. Well, how do give a cpu a 'little more time' in the panic case? For the most part you can't without spinning on the lock and even in that case, how long do you spin for? So instead of making it ugly in the pstore code, just mimic the idea that stop_machine had, which is block on an IRQ IPI until the remote cpu has re-enabled interrupts and left the critical region. Which is what happens now using REBOOT_IRQ. Then leave the NMI case for those cpus that are truly stuck after a short time. This leaves the current behaviour alone and just handle a corner case. Most systems should never have to enter the NMI code and if they do, print out a message in case the NMI itself causes another issue. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1336761675-24296-3-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-14Revert "x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus"Don Zickus
This reverts commit 3603a2512f9e69dc87914ba922eb4a0812b21cd6. Originally I wanted a better hammer to shutdown cpus during panic. However, this really steps on the toes of various spinlocks in the panic path. Sometimes it is easier to wait for the IRQ to become re-enabled to indictate the cpu left the critical region and then shutdown the cpu. The next patch moves the NMI addition after the IRQ part. To make it easier to see the logic of everything, revert this patch and apply the next simpler patch. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1336761675-24296-2-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-01-07x86, reboot: Fix typo in nmi reboot pathDon Zickus
It was brought to my attention that my x86 change to use NMI in the reboot path broke Intel Nehalem and Westmere boxes when using kexec. I realized I had mistyped the if statement in commit 3603a2512f9e69dc87914ba922eb4a0812b21cd6 and stuck the ')' in the wrong spot. Putting it in the right spot fixes kexec again. Doh. Reported-by: Yinghai Lu <yinghai@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Don Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/r/1325866671-9797-1-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-05x86, NMI: Add knob to disable using NMI IPIs to stop cpusDon Zickus
Some machines may exhibit problems using the NMI to stop other cpus. This knob just allows one to revert back to the original behaviour to help diagnose the problem. V2: make function static 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/1318533267-18880-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-05x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpusDon Zickus
A recent discussion started talking about the locking on the pstore fs and how it relates to the kmsg infrastructure. We noticed it was possible for userspace to r/w to the pstore fs (grabbing the locks in the process) and block the panic path from r/w to the same fs. The reason was the cpu with the lock could be doing work while the crashing cpu is panic'ing. Busting those spinlocks might cause those cpus to step on each other's data. Fine, fair enough. It was suggested it would be nice to serialize the panic path (ie stop the other cpus) and have only one cpu running. This would allow us to bust the spinlocks and not worry about another cpu stepping on the data. Of course, smp_send_stop() does this in the panic case. kmsg_dump() would have to be moved to be called after it. Easy enough. The only problem is on x86 the smp_send_stop() function calls the REBOOT_VECTOR. Any cpu with irqs disabled (which pstore and its backend ERST would do), block this IPI and thus do not stop. This makes it difficult to reliably log data to the pstore fs. The patch below switches from the REBOOT_VECTOR to NMI (and mimics what kdump does). Switching to NMI allows us to deliver the IPI when irqs are disabled, increasing the reliability of this function. However, Andi carefully noted that on some machines this approach does not work because of broken BIOSes or whatever. To help accomodate this, the next couple of patches will run a selftest and provide a knob to disable. V2: uses atomic ops to serialize the cpu that shuts everyone down V3: comment cleanup 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/1318533267-18880-2-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-31x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULEPaul Gortmaker
These files were implicitly getting EXPORT_SYMBOL via device.h which was including module.h, but that will be fixed up shortly. By fixing these now, we can avoid seeing things like: arch/x86/kernel/rtc.c:29: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL’ arch/x86/kernel/pci-dma.c:20: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL’ arch/x86/kernel/e820.c:69: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_GPL’ [ with input from Randy Dunlap <rdunlap@xenotime.net> and also from Stephen Rothwell <sfr@canb.auug.org.au> ] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-14sched: Provide scheduler_ipi() callback in response to smp_send_reschedule()Peter Zijlstra
For future rework of try_to_wake_up() we'd like to push part of that function onto the CPU the task is actually going to run on. In order to do so we need a generic callback from the existing scheduler IPI. This patch introduces such a generic callback: scheduler_ipi() and implements it as a NOP. BenH notes: PowerPC might use this IPI on offline CPUs under rare conditions! Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152728.744338123@chello.nl
2010-10-21x86, kexec: Make sure to stop all CPUs before exiting the kernelAlok Kataria
x86 smp_ops now has a new op, stop_other_cpus which takes a parameter "wait" this allows the caller to specify if it wants to stop until all the cpus have processed the stop IPI. This is required specifically for the kexec case where we should wait for all the cpus to be stopped before starting the new kernel. We now wait for the cpus to stop in all cases except for panic/kdump where we expect things to be broken and we are doing our best to make things work anyway. This patch fixes a legitimate regression, which was introduced during 2.6.30, by commit id 4ef702c10b5df18ab04921fc252c26421d4d6c75. Signed-off-by: Alok N Kataria <akataria@vmware.com> LKML-Reference: <1286833028.1372.20.camel@ank32.eng.vmware.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: <stable@kernel.org> v2.6.30-36 Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2009-10-09Revert "x86, timers: Check for pending timers after (device) interrupts"Ingo Molnar
This reverts commit 9bcbdd9c58617f1301dd4f17c738bb9bc73aca70. The real bug producing LatencyTop latencies has been fixed in: f5dc375: sched: Update the clock of runqueue select_task_rq() selected And the commit being reverted here triggers local timer processing from every device IRQ. If device IRQs come in at a high frequency, this could cause a performance regression. The commit being reverted here purely 'fixed' the reported latency as a side effect, because CPUs were being moved out of idle more often. Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Frans Pop <elendil@planet.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091008064041.67219b13@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-08x86, timers: Check for pending timers after (device) interruptsArjan van de Ven
Now that range timers and deferred timers are common, I found a problem with these using the "perf timechart" tool. Frans Pop also reported high scheduler latencies via LatencyTop, when using iwlagn. It turns out that on x86, these two 'opportunistic' timers only get checked when another "real" timer happens. These opportunistic timers have the objective to save power by hitchhiking on other wakeups, as to avoid CPU wakeups by themselves as much as possible. The change in this patch runs this check not only at timer interrupts, but at all (device) interrupts. The effect is that: 1) the deferred timers/range timers get delayed less 2) the range timers cause less wakeups by themselves because the percentage of hitchhiking on existing wakeup events goes up. I've verified the working of the patch using "perf timechart", the original exposed bug is gone with this patch. Frans also reported success - the latencies are now down in the expected ~10 msec range. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Tested-by: Frans Pop <elendil@planet.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091008064041.67219b13@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11Merge branch 'linus' into x86/mce3Ingo Molnar
Conflicts: arch/x86/kernel/cpu/mcheck/mce_64.c arch/x86/kernel/irq.c Merge reason: Resolve the conflicts above. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11Merge branch 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
* 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (138 commits) KVM: Prevent overflow in largepages calculation KVM: Disable large pages on misaligned memory slots KVM: Add VT-x machine check support KVM: VMX: Rename rmode.active to rmode.vm86_active KVM: Move "exit due to NMI" handling into vmx_complete_interrupts() KVM: Disable CR8 intercept if tpr patching is active KVM: Do not migrate pending software interrupts. KVM: inject NMI after IRET from a previous NMI, not before. KVM: Always request IRQ/NMI window if an interrupt is pending KVM: Do not re-execute INTn instruction. KVM: skip_emulated_instruction() decode instruction if size is not known KVM: Remove irq_pending bitmap KVM: Do not allow interrupt injection from userspace if there is a pending event. KVM: Unprotect a page if #PF happens during NMI injection. KVM: s390: Verify memory in kvm run KVM: s390: Sanity check on validity intercept KVM: s390: Unlink vcpu on destroy - v2 KVM: s390: optimize float int lock: spin_lock_bh --> spin_lock KVM: s390: use hrtimer for clock wakeup from idle - v2 KVM: s390: Fix memory slot versus run - v3 ...
2009-06-10KVM: use smp_send_reschedule in kvm_vcpu_kickMarcelo Tosatti
KVM uses a function call IPI to cause the exit of a guest running on a physical cpu. For virtual interrupt notification there is no need to wait on IPI receival, or to execute any function. This is exactly what the reschedule IPI does, without the overhead of function IPI. So use it instead of smp_call_function_single in kvm_vcpu_kick. Also change the "guest_mode" variable to a bit in vcpu->requests, and use that to collapse multiple IPI's that would be issued between the first one and zeroing of guest mode. This allows kvm_vcpu_kick to called with interrupts disabled. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-03x86: fix panic with interrupts off (needed for MCE)Andi Kleen
For some time each panic() called with interrupts disabled triggered the !irqs_disabled() WARN_ON in smp_call_function(), producing ugly backtraces and confusing users. This is a common situation with machine checks for example which tend to call panic with interrupts disabled, but will also hit in other situations e.g. panic during early boot. In fact it means that panic cannot be called in many circumstances, which would be bad. This all started with the new fancy queued smp_call_function, which is then used by the shutdown path to shut down the other CPUs. On closer examination it turned out that the fancy RCU smp_call_function() does lots of things not suitable in a panic situation anyways, like allocating memory and relying on complex system state. I originally tried to patch this over by checking for panic there, but it was quite complicated and the original patch was also not very popular. This also didn't fix some of the underlying complexity problems. The new code in post 2.6.29 tries to patch around this by checking for oops_in_progress, but that is not enough to make this fully safe and I don't think that's a real solution because panic has to be reliable. So instead use an own vector to reboot. This makes the reboot code extremly straight forward, which is definitely a big plus in a panic situation where it is important to avoid relying on too much kernel state. The new simple code is also safe to be called from interupts off region because it is very very simple. There can be situations where it is important that panic is reliable. For example on a fatal machine check the panic is needed to get the system up again and running as quickly as possible. So it's important that panic is reliable and all function it calls simple. This is why I came up with this simple vector scheme. It's very hard to beat in simplicity. Vectors are not particularly precious anymore since all big systems are using per CPU vectors. Another possibility would have been to use an NMI similar to kdump, but there is still the problem that NMIs don't work reliably on some systems due to BIOS issues. NMIs would have been able to stop CPUs running with interrupts off too. In the sake of universal reliability I opted for using a non NMI vector for now. I put the reboot vector into the highest priority bucket of the APIC vectors and moved the 64bit UV_BAU message down instead into the next lower priority. [ Impact: bug fix, fixes an old regression ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-04-12x86: smp.c - align smp_ops assignmentsCyrill Gorcunov
Impact: cleanup It's a bit hard to parse by eyes without them being aligned. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> LKML-Reference: <20090412165058.924175574@openvz.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17x86, apic: remove genapic.hIngo Molnar
Impact: cleanup Remove genapic.h and remove all references to it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-31x86: update copyrightsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86, smp: remove mach_ipi.hIngo Molnar
Move mach_ipi.h definitions into genapic.h. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86: remove mach_apic.hIngo Molnar
Spread mach_apic.h definitions into genapic.h. (with some knock-on effects on smp.h and apic.h.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-28x86, apic: untangle the send_IPI_*() jungleIngo Molnar
Our send_IPI_*() methods and definitions are a twisted mess: the same symbol is defined to different things depending on .config details, in a non-transparent way. - spread out the quirks into separately named per apic driver methods - prefix the standard PC methods with default_ - get rid of wrapper macro obfuscation - clean up various details Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-10Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits) x86: fix section mismatch warnings in mcheck/mce_amd_64.c x86: offer frame pointers in all build modes x86: remove duplicated #include's x86: k8 numa register active regions later x86: update Alan Cox's email addresses x86: rename all fields of mpc_table mpc_X to X x86: rename all fields of mpc_oemtable oem_X to X x86: rename all fields of mpc_bus mpc_X to X x86: rename all fields of mpc_cpu mpc_X to X x86: rename all fields of mpc_intsrc mpc_X to X x86: rename all fields of mpc_lintsrc mpc_X to X x86: rename all fields of mpc_iopic mpc_X to X x86: irqinit_64.c init_ISA_irqs should be static Documentation/x86/boot.txt: payload length was changed to payload_length x86: setup_percpu.c fix style problems x86: irqinit_64.c fix style problems x86: irqinit_32.c fix style problems x86: i8259.c fix style problems x86: irq_32.c fix style problems x86: ioport.c fix style problems ...
2009-01-05x86: update Alan Cox's email addressesAlan Cox
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-04x86: cleanup remaining cpumask_t ops in smpboot codeMike Travis
Impact: use new cpumask API to reduce memory and stack usage Allocate the following local cpumasks based on the number of cpus that are present. References will use new cpumask API. (Currently only modified for x86_64, x86_32 continues to use the *_map variants.) cpu_callin_mask cpu_callout_mask cpu_initialized_mask cpu_sibling_setup_mask Provide the following accessor functions: struct cpumask *cpu_sibling_mask(int cpu) struct cpumask *cpu_core_mask(int cpu) Other changes are when setting or clearing the cpu online, possible or present maps, use the accessor functions. Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02Merge branch 'cpus4096-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits) x86: export vector_used_by_percpu_irq x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and() sched: nominate preferred wakeup cpu, fix x86: fix lguest used_vectors breakage, -v2 x86: fix warning in arch/x86/kernel/io_apic.c sched: fix warning in kernel/sched.c sched: move test_sd_parent() to an SMP section of sched.h sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0 sched: activate active load balancing in new idle cpus sched: bias task wakeups to preferred semi-idle packages sched: nominate preferred wakeup cpu sched: favour lower logical cpu number for sched_mc balance sched: framework for sched_mc/smt_power_savings=N sched: convert BALANCE_FOR_xx_POWER to inline functions x86: use possible_cpus=NUM to extend the possible cpus allowed x86: fix cpu_mask_to_apicid_and to include cpu_online_mask x86: update io_apic.c to the new cpumask code x86: Introduce topology_core_cpumask()/topology_thread_cpumask() x86: xen: use smp_call_function_many() x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c ... Fixed up trivial conflict in kernel/time/tick-sched.c manually
2008-12-23Merge branch 'x86/irq' into x86/coreIngo Molnar
2008-12-16x86: cosmetic changes apic-related files.Mike Travis
This patch simply changes cpumask_t to struct cpumask and similar trivial modernizations. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
2008-12-16x86 smp: modify send_IPI_mask interface to accept cpumask_t pointersMike Travis
Impact: cleanup, change parameter passing * Change genapic interfaces to accept cpumask_t pointers where possible. * Modify external callers to use cpumask_t pointers in function calls. * Create new send_IPI_mask_allbutself which is the same as the send_IPI_mask functions but removes smp_processor_id() from list. This removes another common need for a temporary cpumask_t variable. * Functions that used a temp cpumask_t variable for: cpumask_t allbutme = cpu_online_map; cpu_clear(smp_processor_id(), allbutme); if (!cpus_empty(allbutme)) ... become: if (!cpus_equal(cpu_online_map, cpumask_of_cpu(cpu))) ... * Other minor code optimizations (like using cpus_clear instead of CPU_MASK_NONE, etc.) Applies to linux-2.6.tip/master. Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Ingo Molnar <mingo@elte.hu>
2008-12-12x86: hardirq: introduce inc_irq_stat()Hiroshi Shimamoto
Impact: cleanup Introduce inc_irq_stat() macro and unify irq_stat accounting code. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-11x86: call machine_shutdown and stop all CPUs in native_machine_haltIvan Vecera
Impact: really halt all CPUs on halt Function machine_halt (resp. native_machine_halt) is empty for x86 architectures. When command 'halt -f' is invoked, the message "System halted." is displayed but this is not really true because all CPUs are still running. There are also similar inconsistencies for other arches (some uses power-off for halt or forever-loop with IRQs enabled/disabled). IMO there should be used the same approach for all architectures OR what does the message "System halted" really mean? This patch fixes it for x86. Signed-off-by: Ivan Vecera <ivecera@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-25x86: add cpu hotplug hooks into smp_opsAlex Nixon
Signed-off-by: Alex Nixon <alex.nixon@citrix.com> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-06generic-ipi: fixletJens Axboe
create proper stackframe. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-26smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe
It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-06-26x86: convert to generic helpers for IPI function callsJens Axboe
This converts x86, x86-64, and xen to use the new helpers for smp_call_function() and friends, and adds support for smp_call_function_single(). Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-13x86: fix app crashes after SMP resumeHugh Dickins
After resume on a 2cpu laptop, kernel builds collapse with a sed hang, sh or make segfault (often on 20295564), real-time signal to cc1 etc. Several hurdles to jump, but a manually-assisted bisect led to -rc1's d2bcbad5f3ad38a1c09861bca7e252dde7bb8259 x86: do not zap_low_mappings in __smp_prepare_cpus. Though the low mappings were removed at bootup, they were left behind (with Global flags helping to keep them in TLB) after resume or cpu online, causing the crashes seen. Reinstate zap_low_mappings (with local __flush_tlb_all) for each cpu_up on x86_32. This used to be serialized by smp_commenced_mask: that's now gone, but a low_mappings flag will do. No need for native_smp_cpus_done to repeat the zap: let mem_init zap BSP's low mappings just like on UP. (In passing, fix error code from native_cpu_up: do_boot_cpu returns a variety of diagnostic values, Dprintk what it says but convert to -EIO. And save_pg_dir separately before zap_low_mappings: doesn't matter now, but zapping twice in succession wiped out resume's swsusp_pg_dir.) That worked well on the duo and one quad, but wouldn't boot 3rd or 4th cpu on P4 Xeon, oopsing just after unlock_ipi_call_lock. The TLB flush IPI now being sent reveals a long-standing bug: the booting cpu has its APIC readied in smp_callin at the top of start_secondary, but isn't put into the cpu_online_map until just before that unlock_ipi_call_lock. So native_smp_call_function_mask to online cpus would send_IPI_allbutself, including the cpu just coming up, though it has been excluded from the count to wait for: by the time it handles the IPI, the call data on native_smp_call_function_mask's stack may well have been overwritten. So fall back to send_IPI_mask while cpu_online_map does not match cpu_callout_map: perhaps there's a better APICological fix to be made at the start_secondary end, but I wouldn't know that. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: move ipi definitions to mach_ipi.hGlauber Costa
take them out of the x86_64-only asm/mach_apic.h Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: Don't send RESCHEDULE_VECTOR to offlined cpusGautham R Shenoy
In the x86 native_smp_send_reschedule_function(), don't send the IPI if the cpu has gone offline already. Warn nevertheless!! Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: get rid of smp_32.c and smp_64.cGlauber Costa
This patch merges the copyright notices, and valuable comments that were left back on smp_{32,64}.c. With that, files are empty, and are deleted Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: create smp.cGlauber Costa
this patch moves all the functions and data structures that look like exactly the same from smp_{32,64}.c to smp.c Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>