- 07 7月, 2015 1 次提交
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由 Thomas Gleixner 提交于
Jin debugged a nasty cpu hotplug race which results in leaking a irq vector on the newly hotplugged cpu. cpu N cpu M native_cpu_up device_shutdown do_boot_cpu free_msi_irqs start_secondary arch_teardown_msi_irqs smp_callin default_teardown_msi_irqs setup_vector_irq arch_teardown_msi_irq __setup_vector_irq native_teardown_msi_irq lock(vector_lock) destroy_irq install vectors unlock(vector_lock) lock(vector_lock) ---> __clear_irq_vector unlock(vector_lock) lock(vector_lock) set_cpu_online unlock(vector_lock) This leaves the irq vector(s) which are torn down on CPU M stale in the vector array of CPU N, because CPU M does not see CPU N online yet. There is a similar issue with concurrent newly setup interrupts. The alloc/free protection of irq descriptors does not prevent the above race, because it merily prevents interrupt descriptors from going away or changing concurrently. Prevent this by moving the call to setup_vector_irq() into the vector_lock held region which protects set_cpu_online(): cpu N cpu M native_cpu_up device_shutdown do_boot_cpu free_msi_irqs start_secondary arch_teardown_msi_irqs smp_callin default_teardown_msi_irqs lock(vector_lock) arch_teardown_msi_irq setup_vector_irq() __setup_vector_irq native_teardown_msi_irq install vectors destroy_irq set_cpu_online unlock(vector_lock) lock(vector_lock) __clear_irq_vector unlock(vector_lock) So cpu M either sees the cpu N online before clearing the vector or cpu N installs the vectors after cpu M has cleared it. Reported-by: Nxiao jin <jin.xiao@intel.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Joerg Roedel <jroedel@suse.de> Cc: Borislav Petkov <bp@suse.de> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Link: http://lkml.kernel.org/r/20150705171102.141898931@linutronix.de
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- 06 7月, 2015 2 次提交
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由 Zhu Guihua 提交于
As we alloc pages with GFP_KERNEL in init_espfix_ap() which is called before we enable local irqs, so the lockdep sub-system would (correctly) trigger a warning about the potentially blocking API. So we allocate them on the boot CPU side when the secondary CPU is brought up by the boot CPU, and hand them over to the secondary CPU. And we use alloc_pages_node() with the secondary CPU's node, to make sure the espfix stack is NUMA-local to the CPU that is going to use it. Signed-off-by: NZhu Guihua <zhugh.fnst@cn.fujitsu.com> Cc: <bp@alien8.de> Cc: <luto@amacapital.net> Cc: <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/c97add2670e9abebb90095369f0cfc172373ac94.1435824469.git.zhugh.fnst@cn.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Zhu Guihua 提交于
Add a CPU index parameter to init_espfix_ap(), so that the parameter could be propagated to the function for espfix page allocation. Signed-off-by: NZhu Guihua <zhugh.fnst@cn.fujitsu.com> Cc: <bp@alien8.de> Cc: <luto@amacapital.net> Cc: <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/cde3fcf1b3211f3f03feb1a995bce3fee850f0fc.1435824469.git.zhugh.fnst@cn.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 27 5月, 2015 1 次提交
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由 Bartosz Golaszewski 提交于
The former duplicate the functionalities of the latter but are neither documented nor arch-independent. Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-9-git-send-email-bgolaszewski@baylibre.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 5月, 2015 2 次提交
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由 Ingo Molnar 提交于
This unifies all the FPU related header files under a unified, hiearchical naming scheme: - asm/fpu/types.h: FPU related data types, needed for 'struct task_struct', widely included in almost all kernel code, and hence kept as small as possible. - asm/fpu/api.h: FPU related 'public' methods exported to other subsystems. - asm/fpu/internal.h: FPU subsystem internal methods - asm/fpu/xsave.h: XSAVE support internal methods (Also standardize the header guard in asm/fpu/internal.h.) Reviewed-by: NBorislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
Fix a minor header file dependency bug in asm/fpu-internal.h: it relies on i387.h but does not include it. All users of fpu-internal.h included it explicitly. Also remove unnecessary includes, to reduce compilation time. This also makes it easier to use it as a standalone header file for FPU internals, such as an upcoming C module in arch/x86/kernel/fpu/. Reviewed-by: NBorislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 18 5月, 2015 1 次提交
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由 Ingo Molnar 提交于
So while testing kernels using tools/kvm/ (kvmtool) I noticed that it booted super slow: [ 0.142991] Performance Events: no PMU driver, software events only. [ 0.149265] x86: Booting SMP configuration: [ 0.149765] .... node #0, CPUs: #1 [ 0.148304] kvm-clock: cpu 1, msr 2:1bfe9041, secondary cpu clock [ 10.158813] KVM setup async PF for cpu 1 [ 10.159000] #2 [ 10.159000] kvm-stealtime: cpu 1, msr 211a4d400 [ 10.158829] kvm-clock: cpu 2, msr 2:1bfe9081, secondary cpu clock [ 20.167805] KVM setup async PF for cpu 2 [ 20.168000] #3 [ 20.168000] kvm-stealtime: cpu 2, msr 211a8d400 [ 20.167818] kvm-clock: cpu 3, msr 2:1bfe90c1, secondary cpu clock [ 30.176902] KVM setup async PF for cpu 3 [ 30.177000] #4 [ 30.177000] kvm-stealtime: cpu 3, msr 211acd400 One CPU booted up per 10 seconds. With 120 CPUs that takes a while. Bisection pinpointed this commit: 853b160a ("Revert f5d6a52f ("x86/smpboot: Skip delays during SMP initialization similar to Xen")") But that commit just restores previous behavior, so it cannot cause the problem. After some head scratching it turns out that these two commits: 1a744cb3 ("x86/smp/boot: Remove 10ms delay from cpu_up() on modern processors") d68921f9 ("x86/smp/boot: Add cmdline "cpu_init_udelay=N" to specify cpu_up() delay") added the following code to smpboot.c: - mdelay(10); + mdelay(init_udelay); Note the mismatch in the units: the delay is called 'udelay' and is set to microseconds - while the function used here is actually 'mdelay', which counts in milliseconds ... So the delay for legacy systems is off by a factor of 1,000, so instead of 10 msecs we waited for 10 seconds ... The reason bisection pointed to 853b160a was that 853b160a removed a (broken) boot-time speedup patch, which masked the factor 1,000 bug. Fix it by using udelay(). This fixes my bootup problems. Cc: Len Brown <len.brown@intel.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 13 5月, 2015 1 次提交
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由 Ingo Molnar 提交于
Huang Ying reported x86 boot hangs due to this commit. Turns out that the change, despite its changelog, does more than just change timeouts: it also changes the way we assert/deassert INIT via the APIC_DM_INIT IPI, in the x2apic case it skips the deassert step. This is historically fragile code and the patch did not improve it, so revert these changes. This commit: 1a744cb3 ("x86/smp/boot: Remove 10ms delay from cpu_up() on modern processors") independently removes the worst of the delays (the 10 msec delay). The remaining delays can be addressed one by one, combined with careful testing. Reported-by: NHuang Ying <ying.huang@intel.com> Cc: Anthony Liguori <aliguori@amazon.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Gang Wei <gang.wei@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Cc: Len Brown <len.brown@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Deegan <tim@xen.org> Link: http://lkml.kernel.org/r/1430732554-7294-1-git-send-email-jschoenh@amazon.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 12 5月, 2015 2 次提交
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由 Len Brown 提交于
Modern processor familes do not require the 10ms delay in cpu_up() to de-assert INIT. This speeds up boot and resume by 10ms per (application) processor. Signed-off-by: NLen Brown <len.brown@intel.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/021ce30c88f216ad39686646421194dc25671e55.1431379433.git.len.brown@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Len Brown 提交于
No change to default behavior. Replace the hard-coded mdelay(10) in cpu_up() with a variable udelay, that is set to a defined default -- rather than a magic number. Add a boot-time override, "cpu_init_udelay=N" Signed-off-by: NLen Brown <len.brown@intel.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/2fe8e6c798e8def271122f62df9bbf58dc283e2a.1431379433.git.len.brown@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 08 5月, 2015 1 次提交
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由 Denys Vlasenko 提交于
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NAndy Lutomirski <luto@kernel.org> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1429889495-27850-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 06 5月, 2015 1 次提交
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由 Jan H. Schönherr 提交于
Remove the per-CPU delays during SMP initialization, which seems to be possible on newer architectures with an x2APIC. Xen does this since 2011. In fact, this commit is basically a combination of the following Xen commits. The first removes the delays, the second fixes an issue with the removal: commit 68fce206f6dba9981e8322269db49692c95ce250 Author: Tim Deegan <Tim.Deegan@citrix.com> Date: Tue Jul 19 14:13:01 2011 +0100 x86: Remove timeouts from INIT-SIPI-SIPI sequence when using x2apic. Some of the timeouts are pointless since they're waiting for the ICR to ack the IPI delivery and that doesn't happen on x2apic. The others should be benign (and are suggested in the SDM) but removing them makes AP bringup much more reliable on some test boxes. Signed-off-by: NTim Deegan <Tim.Deegan@citrix.com> commit f12ee533150761df5a7099c83f2a5fa6c07d1187 Author: Gang Wei <gang.wei@intel.com> Date: Thu Dec 29 10:07:54 2011 +0000 X86: Add a delay between INIT & SIPIs for tboot AP bring-up in X2APIC case Without this delay, Xen could not bring APs up while working with TXT/tboot, because tboot needs some time in APs to handle INIT before becoming ready for receiving SIPIs (this delay was removed as part of c/s 23724 by Tim Deegan). Signed-off-by: NGang Wei <gang.wei@intel.com> Acked-by: NKeir Fraser <keir@xen.org> Acked-by: NTim Deegan <tim@xen.org> Committed-by: NTim Deegan <tim@xen.org> Signed-off-by: NJan H. Schönherr <jschoenh@amazon.de> Cc: Anthony Liguori <aliguori@amazon.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Gang Wei <gang.wei@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Len Brown <len.brown@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Deegan <tim@xen.org> Link: http://lkml.kernel.org/r/1430732554-7294-1-git-send-email-jschoenh@amazon.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 02 4月, 2015 1 次提交
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由 Boris Ostrovsky 提交于
Some of x86 bare-metal and Xen CPU initialization code is common between the two and therefore can be factored out to avoid code duplication. As a side effect, doing so will also extend the fix provided by commit a7fcf28d ("x86/asm/entry: Replace this_cpu_sp0() with current_top_of_stack() to x86_32") to 32-bit Xen PV guests. Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1427897534-5086-1-git-send-email-boris.ostrovsky@oracle.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 4月, 2015 1 次提交
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由 Bandan Das 提交于
__verify_local_APIC() is detritus from the early APIC days. Its return value isn't used anywhere and the information it prints when debug is enabled is already part of APIC initialization messages printed to syslog. Off with it! Signed-off-by: NBandan Das <bsd@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/jpgy4mcsxsq.fsf@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 3月, 2015 1 次提交
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由 Denys Vlasenko 提交于
PER_CPU_VAR(kernel_stack) was set up in a way where it points five stack slots below the top of stack. Presumably, it was done to avoid one "sub $5*8,%rsp" in syscall/sysenter code paths, where iret frame needs to be created by hand. Ironically, none of them benefits from this optimization, since all of them need to allocate additional data on stack (struct pt_regs), so they still have to perform subtraction. This patch eliminates KERNEL_STACK_OFFSET. PER_CPU_VAR(kernel_stack) now points directly to top of stack. pt_regs allocations are adjusted to allocate iret frame as well. Hopefully we can merge it later with 32-bit specific PER_CPU_VAR(cpu_current_top_of_stack) variable... Net result in generated code is that constants in several insns are changed. This change is necessary for changing struct pt_regs creation in SYSCALL64 code path from MOV to PUSH instructions. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NBorislav Petkov <bp@suse.de> Acked-by: NAndy Lutomirski <luto@kernel.org> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1426785469-15125-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 12 3月, 2015 1 次提交
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由 Paul E. McKenney 提交于
This commit removes the open-coded CPU-offline notification with new common code. Among other things, this change avoids calling scheduler code using RCU from an offline CPU that RCU is ignoring. It also allows Xen to notice at online time that the CPU did not go offline correctly. Note that Xen has the surviving CPU carry out some cleanup operations, so if the surviving CPU times out, these cleanup operations might have been carried out while the outgoing CPU was still running. It might therefore be unwise to bring this CPU back online, and this commit avoids doing so. Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: <x86@kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: <xen-devel@lists.xenproject.org>
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- 07 3月, 2015 1 次提交
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由 Andy Lutomirski 提交于
I broke 32-bit kernels. The implementation of sp0 was correct as far as I can tell, but sp0 was much weirder on x86_32 than I realized. It has the following issues: - Init's sp0 is inconsistent with everything else's: non-init tasks are offset by 8 bytes. (I have no idea why, and the comment is unhelpful.) - vm86 does crazy things to sp0. Fix it up by replacing this_cpu_sp0() with current_top_of_stack() and using a new percpu variable to track the top of the stack on x86_32. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 75182b16 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()") Link: http://lkml.kernel.org/r/d09dbe270883433776e0cbee3c7079433349e96d.1425692936.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 22 1月, 2015 6 次提交
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由 Thomas Gleixner 提交于
Now that the APIC bringup is consolidated we can move the setup call for the percpu clock event device to apic_bsp_setup(). Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20150115211704.162567839@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
Extend apic_bsp_setup() so the same code flow can be used for APIC_init_uniprocessor(). Folded Jiangs fix to provide proper ordering of the UP setup. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20150115211704.084765674@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
The UP related setups for local apic are mangled into smp_sanity_check(). That results in duplicate calls to disable_smp() and makes the code hard to follow. Let smp_sanity_check() return dedicated values for the various exit reasons and handle them at the call site. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NBorislav Petkov <bp@alien8.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20150115211703.987833932@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
We better provide proper functions which implement the required code flow in the apic code rather than letting the smpboot code open code it. That allows to make more functions static and confines the APIC functionality to apic.c where it belongs. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NBorislav Petkov <bp@alien8.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20150115211703.907616730@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
smpboot is very creative with the ways to disable ioapic. smpboot_clear_io_apic() smpboot_clear_io_apic_irqs() and disable_ioapic_support() serve a similar purpose. smpboot_clear_io_apic_irqs() is the most useless of all functions as it clears a variable which has not been setup yet. Aside of that it has the same ifdef mess and conditionals around the ioapic related code, which can now be removed. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NBorislav Petkov <bp@alien8.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20150115211703.650280684@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Thomas Gleixner 提交于
No point for a separate header file. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/20150115211703.304126687@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 16 12月, 2014 1 次提交
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由 Thomas Gleixner 提交于
There is no reason to keep preemption disabled in this function. We only have two other threads live: kthreadd and idle. Neither of them is going to preempt. But that preempt_disable forces all the code inside to do GFP_ATOMIC allocations which is just insane. Remove it. Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Tested-by: NBorislav Petkov <bp@alien8.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20141205084147.153643952@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 10 11月, 2014 1 次提交
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由 Boris Ostrovsky 提交于
Commit 2ed53c0d ("x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3") introduced completions to CPU offlining process. These completions are not initialized on Xen kernels causing a panic in play_dead_common(). Move handling of die_complete into common routines to make them available to Xen guests. Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com> Cc: tianyu.lan@intel.com Cc: konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414770572-7950-1-git-send-email-boris.ostrovsky@oracle.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 05 11月, 2014 1 次提交
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由 Jan Beulich 提交于
Both this_cpu_off and cpu_info aren't getting modified post boot, yet are being accessed on enough code paths that grouping them with other frequently read items seems desirable. For cpu_info this at the same time implies removing the cache line alignment (which afaict became pointless when it got converted to per-CPU data years ago). Signed-off-by: NJan Beulich <jbeulich@suse.com> Link: http://lkml.kernel.org/r/54589BD20200007800044A84@mail.emea.novell.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 19 10月, 2014 1 次提交
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由 Ingo Molnar 提交于
Makes the code more readable by moving variable and usage closer to each other, which also avoids this build warning in the !CONFIG_HOTPLUG_CPU case: arch/x86/kernel/smpboot.c:105:42: warning: ‘die_complete’ defined but not used [-Wunused-variable] Cc: Prarit Bhargava <prarit@redhat.com> Cc: Lan Tianyu <tianyu.lan@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: srostedt@redhat.com Cc: toshi.kani@hp.com Cc: imammedo@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 03 10月, 2014 1 次提交
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由 Dave Hansen 提交于
Commit: cebf15eb ("x86, sched: Add new topology for multi-NUMA-node CPUs") some code to try to detect the situation where we have a NUMA node inside of the "DIE" sched domain. It detected this by looking for cpus which match_die() but do not match NUMA nodes via topology_same_node(). I wrote it up as: if (match_die(c, o) == !topology_same_node(c, o)) which actually seemed to work some of the time, albiet accidentally. It should have been doing an &&, not an ==. This code essentially chopped off the "DIE" domain on one of Andrew Morton's systems. He reported that this patch fixed his issue. Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com> Reported-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Dave Hansen <dave@sr71.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Lan Tianyu <tianyu.lan@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Toshi Kani <toshi.kani@hp.com> Link: http://lkml.kernel.org/r/20140930214546.FD481CFF@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 24 9月, 2014 3 次提交
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由 Wanpeng Li 提交于
The following bug can be triggered by hot adding and removing a large number of xen domain0's vcpus repeatedly: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group PGD 5a9d5067 PUD 13067 PMD 0 Oops: 0000 [#3] SMP [...] Call Trace: load_balance ? _raw_spin_unlock_irqrestore idle_balance __schedule schedule schedule_timeout ? lock_timer_base schedule_timeout_uninterruptible msleep lock_device_hotplug_sysfs online_store dev_attr_store sysfs_write_file vfs_write SyS_write system_call_fastpath Last level cache shared mask is built during CPU up and the build_sched_domain() routine takes advantage of it to setup the sched domain CPU topology. However, llc_shared_mask is not released during CPU disable, which leads to an invalid sched domainCPU topology. This patch fix it by releasing the llc_shared_mask correctly during CPU disable. Yasuaki also reported that this can happen on real hardware: https://lkml.org/lkml/2014/7/22/1018 His case is here: == Here is an example on my system. My system has 4 sockets and each socket has 15 cores and HT is enabled. In this case, each core of sockes is numbered as follows: | CPU# Socket#0 | 0-14 , 60-74 Socket#1 | 15-29, 75-89 Socket#2 | 30-44, 90-104 Socket#3 | 45-59, 105-119 Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000. It means that last level cache of Socket#2 is shared with CPU#30-44 and 90-104. When hot-removing socket#2 and #3, each core of sockets is numbered as follows: | CPU# Socket#0 | 0-14 , 60-74 Socket#1 | 15-29, 75-89 But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30 remains having 0x3fff80000001fffc0000000. After that, when hot-adding socket#2 and #3, each core of sockets is numbered as follows: | CPU# Socket#0 | 0-14 , 60-74 Socket#1 | 15-29, 75-89 Socket#2 | 30-59 Socket#3 | 90-119 Then llc_shared_mask of CPU#30 becomes 0x3fff8000fffffffc0000000. It means that last level cache of Socket#2 is shared with CPU#30-59 and 90-104. So the mask has the wrong value. Signed-off-by: NWanpeng Li <wanpeng.li@linux.intel.com> Tested-by: NLinn Crosetto <linn@hp.com> Reviewed-by: NBorislav Petkov <bp@suse.de> Reviewed-by: NToshi Kani <toshi.kani@hp.com> Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: <stable@vger.kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Lan Tianyu 提交于
With certain kernel configurations, CPU offline consumes more than 100ms during S3. It's a timing related issue: native_cpu_die() would occasionally fall into a 100ms sleep when the CPU idle loop thread marked the CPU state to DEAD too slowly. What native_cpu_die() does is that it polls the CPU state and waits for 100ms if CPU state hasn't been marked to DEAD. The 100ms sleep doesn't make sense and is purely historic. To avoid such long sleeping, this patch adds a 'struct completion' to each CPU, waits for the completion in native_cpu_die() and wakes up the completion when the CPU state is marked to DEAD. Tested on an Intel Xeon server with 48 cores, Ivybridge and on Haswell laptops. The CPU offlining cost on these machines is reduced from more than 100ms to less than 5ms. The system suspend time is reduced by 2.3s on the servers. Borislav and Prarit also helped to test the patch on an AMD machine and a few systems of various sizes and configurations (multi-socket, single-socket, no hyper threading, etc.). No issues were seen. Tested-by: NPrarit Bhargava <prarit@redhat.com> Signed-off-by: NLan Tianyu <tianyu.lan@intel.com> Acked-by: NBorislav Petkov <bp@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: srostedt@redhat.com Cc: toshi.kani@hp.com Cc: imammedo@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.com [ Improved a few minor details in the code, cleaned up the changelog. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Dave Hansen 提交于
I'm getting the spew below when booting with Haswell (Xeon E5-2699 v3) CPUs and the "Cluster-on-Die" (CoD) feature enabled in the BIOS. It seems similar to the issue that some folks from AMD ran in to on their systems and addressed in this commit: 161270fc ("x86/smp: Fix topology checks on AMD MCM CPUs") Both these Intel and AMD systems break an assumption which is being enforced by topology_sane(): a socket may not contain more than one NUMA node. AMD special-cased their system by looking for a cpuid flag. The Intel mode is dependent on BIOS options and I do not know of a way which it is enumerated other than the tables being parsed during the CPU bringup process. In other words, we have to trust the ACPI tables <shudder>. This detects the situation where a NUMA node occurs at a place in the middle of the "CPU" sched domains. It replaces the default topology with one that relies on the NUMA information from the firmware (SRAT table) for all levels of sched domains above the hyperthreads. This also fixes a sysfs bug. We used to freak out when we saw the "mc" group cross a node boundary, so we stopped building the MC group. MC gets exported as the 'core_siblings_list' in /sys/devices/system/cpu/cpu*/topology/ and this caused CPUs with the same 'physical_package_id' to not be listed together in 'core_siblings_list'. This violates a statement from Documentation/ABI/testing/sysfs-devices-system-cpu: core_siblings: internal kernel map of cpu#'s hardware threads within the same physical_package_id. core_siblings_list: human-readable list of the logical CPU numbers within the same physical_package_id as cpu#. The sysfs effects here cause an issue with the hwloc tool where it gets confused and thinks there are more sockets than are physically present. Before this patch, there are two packages: # cd /sys/devices/system/cpu/ # cat cpu*/topology/physical_package_id | sort | uniq -c 18 0 18 1 But 4 _sets_ of core siblings: # cat cpu*/topology/core_siblings_list | sort | uniq -c 9 0-8 9 18-26 9 27-35 9 9-17 After this set, there are only 2 sets of core siblings, which is what we expect for a 2-socket system. # cat cpu*/topology/physical_package_id | sort | uniq -c 18 0 18 1 # cat cpu*/topology/core_siblings_list | sort | uniq -c 18 0-17 18 18-35 Example spew: ... NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter. #2 #3 #4 #5 #6 #7 #8 .... node #1, CPUs: #9 ------------[ cut here ]------------ WARNING: CPU: 9 PID: 0 at /home/ak/hle/linux-hle-2.6/arch/x86/kernel/smpboot.c:306 topology_sane.isra.2+0x74/0x90() sched: CPU #9's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency. Modules linked in: CPU: 9 PID: 0 Comm: swapper/9 Not tainted 3.17.0-rc1-00293-g8e01c4d-dirty #631 Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0036.R05.1407140519 07/14/2014 0000000000000009 ffff88046ddabe00 ffffffff8172e485 ffff88046ddabe48 ffff88046ddabe38 ffffffff8109691d 000000000000b001 0000000000000009 ffff88086fc12580 000000000000b020 0000000000000009 ffff88046ddabe98 Call Trace: [<ffffffff8172e485>] dump_stack+0x45/0x56 [<ffffffff8109691d>] warn_slowpath_common+0x7d/0xa0 [<ffffffff8109698c>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff81074f94>] topology_sane.isra.2+0x74/0x90 [<ffffffff8107530e>] set_cpu_sibling_map+0x31e/0x4f0 [<ffffffff8107568d>] start_secondary+0x1ad/0x240 ---[ end trace 3fe5f587a9fcde61 ]--- #10 #11 #12 #13 #14 #15 #16 #17 .... node #2, CPUs: #18 #19 #20 #21 #22 #23 #24 #25 #26 .... node #3, CPUs: #27 #28 #29 #30 #31 #32 #33 #34 #35 Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com> [ Added LLC domain and s/match_mc/match_die/ ] Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: David Rientjes <rientjes@google.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: brice.goglin@gmail.com Cc: "H. Peter Anvin" <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/20140918193334.C065EBCE@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 16 9月, 2014 1 次提交
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由 Igor Mammedov 提交于
Hang is observed on virtual machines during CPU hotplug, especially in big guests with many CPUs. (It reproducible more often if host is over-committed). It happens because master CPU gives up waiting on secondary CPU and allows it to run wild. As result AP causes locking or crashing system. For example as described here: https://lkml.org/lkml/2014/3/6/257 If master CPU have sent STARTUP IPI successfully, and AP signalled to master CPU that it's ready to start initialization, make master CPU wait indefinitely till AP is onlined. To ensure that AP won't ever run wild, make it wait at early startup till master CPU confirms its intention to wait for AP. If AP doesn't respond in 10 seconds, the master CPU will timeout and cancel AP onlining. Signed-off-by: NIgor Mammedov <imammedo@redhat.com> Acked-by: NToshi Kani <toshi.kani@hp.com> Tested-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1403266991-12233-1-git-send-email-imammedo@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 31 7月, 2014 2 次提交
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由 David Rientjes 提交于
Since commit b5660ba7 ("x86, platforms: Remove NUMAQ") removed NUMAQ, the setup_portio_remap() apic callback has been obsolete. Remove it. Signed-off-by: NDavid Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302351480.17503@chino.kir.corp.google.comSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
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由 David Rientjes 提交于
Since commit b5660ba7 ("x86, platforms: Remove NUMAQ") removed NUMAQ, the smp_callin_clear_local_apic() apic callback has been obsolete. Remove it. Signed-off-by: NDavid Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302349040.17503@chino.kir.corp.google.comSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 09 6月, 2014 1 次提交
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由 Linus Torvalds 提交于
This reverts commit 3e1a878b. It came in very late, and already has one reported failure: Sitsofe reports that the current tree fails to boot on his EeePC, and bisected it down to this. Rather than waste time trying to figure out what's wrong, just revert it. Reported-by: NSitsofe Wheeler <sitsofe@gmail.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: NIngo Molnar <mingo@kernel.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 6月, 2014 3 次提交
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由 Igor Mammedov 提交于
Hang is observed on virtual machines during CPU hotplug, especially in big guests with many CPUs. (It reproducible more often if host is over-committed). It happens because master CPU gives up waiting on secondary CPU and allows it to run wild. As result AP causes locking or crashing system. For example as described here: https://lkml.org/lkml/2014/3/6/257 If master CPU have sent STARTUP IPI successfully, and AP signalled to master CPU that it's ready to start initialization, make master CPU wait indefinitely till AP is onlined. To ensure that AP won't ever run wild, make it wait at early startup till master CPU confirms its intention to wait for AP. If AP doesn't respond in 10 seconds, the master CPU will timeout and cancel AP onlining. Signed-off-by: NIgor Mammedov <imammedo@redhat.com> Acked-by: NToshi Kani <toshi.kani@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1401975765-22328-4-git-send-email-imammedo@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Igor Mammedov 提交于
If system is running without debug level logging, it will not log error if do_boot_cpu() failed to wakeup AP. It may lead to silent AP bringup failures at boot time. Change message level to KERN_ERR to make error visible to user as it's done on other architectures. Signed-off-by: NIgor Mammedov <imammedo@redhat.com> Acked-by: NToshi Kani <toshi.kani@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1401975765-22328-3-git-send-email-imammedo@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Igor Mammedov 提交于
currently if AP wake up is failed, master CPU marks AP as not present in do_boot_cpu() by calling set_cpu_present(cpu, false). That leads to following list corruption on the next physical CPU hotplug: [ 418.107336] WARNING: CPU: 1 PID: 45 at lib/list_debug.c:33 __list_add+0xbe/0xd0() [ 418.115268] list_add corruption. prev->next should be next (ffff88003dc57600), but was ffff88003e20c3a0. (prev=ffff88003e20c3a0). [ 418.123693] Modules linked in: nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT ipt_REJECT cfg80211 xt_conntrack rfkill ee [ 418.138979] CPU: 1 PID: 45 Comm: kworker/u10:1 Not tainted 3.14.0-rc6+ #387 [ 418.149989] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007 [ 418.165750] Workqueue: kacpi_hotplug acpi_hotplug_work_fn [ 418.166433] 0000000000000021 ffff880038ca7988 ffffffff8159b22d 0000000000000021 [ 418.176460] ffff880038ca79d8 ffff880038ca79c8 ffffffff8106942c ffff880038ca79e8 [ 418.177453] ffff88003e20c3a0 ffff88003dc57600 ffff88003e20c3a0 00000000ffffffea [ 418.178445] Call Trace: [ 418.185811] [<ffffffff8159b22d>] dump_stack+0x49/0x5c [ 418.186440] [<ffffffff8106942c>] warn_slowpath_common+0x8c/0xc0 [ 418.187192] [<ffffffff81069516>] warn_slowpath_fmt+0x46/0x50 [ 418.191231] [<ffffffff8136ef51>] ? acpi_ns_get_node+0xb7/0xc7 [ 418.193889] [<ffffffff812f796e>] __list_add+0xbe/0xd0 [ 418.196649] [<ffffffff812e2aa9>] kobject_add_internal+0x79/0x200 [ 418.208610] [<ffffffff812e2e18>] kobject_add_varg+0x38/0x60 [ 418.213831] [<ffffffff812e2ef4>] kobject_add+0x44/0x70 [ 418.229961] [<ffffffff813e2c60>] device_add+0xd0/0x550 [ 418.234991] [<ffffffff813f0e95>] ? pm_runtime_init+0xe5/0xf0 [ 418.250226] [<ffffffff813e32be>] device_register+0x1e/0x30 [ 418.255296] [<ffffffff813e82a3>] register_cpu+0xe3/0x130 [ 418.266539] [<ffffffff81592be5>] arch_register_cpu+0x65/0x150 [ 418.285845] [<ffffffff81355c0d>] acpi_processor_hotadd_init+0x5a/0x9b ... Which is caused by the fact that generic_processor_info() allocates logical CPU id by calling: cpu = cpumask_next_zero(-1, cpu_present_mask); which returns id of previously failed to wake up CPU, since its bit is cleared by do_boot_cpu() and as result register_cpu() tries to register another CPU with the same id as already present but failed to be onlined CPU. Taking in account that AP will not do anything if master CPU failed to wake it up, there is no reason to mark that AP as not present and break next cpu hotplug attempts. As a side effect of not marking AP as not present, user would be allowed to online it again later. Also fix memory corruption in acpi_unmap_lsapic() if during CPU hotplug master CPU failed to wake up AP it set percpu x86_cpu_to_apicid to BAD_APICID=0xFFFF for AP. However following attempt to unplug that CPU will lead to out of bound write access to __apicid_to_node[] which is 32768 items long on x86_64 kernel. So with above fix of cpu_present_mask make sure that a present CPU has a valid APIC ID by not setting x86_cpu_to_apicid to BAD_APICID in do_boot_cpu() on failure and allow acpi_processor_remove()->acpi_unmap_lsapic() cleanly remove CPU. Signed-off-by: NIgor Mammedov <imammedo@redhat.com> Acked-by: NToshi Kani <toshi.kani@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1401975765-22328-2-git-send-email-imammedo@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 05 5月, 2014 1 次提交
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由 H. Peter Anvin 提交于
Make espfix64 a hidden Kconfig option. This fixes the x86-64 UML build which had broken due to the non-existence of init_espfix_bsp() in UML: since UML uses its own Kconfig, this option does not appear in the UML build. This also makes it possible to make support for 16-bit segments a configuration option, for the people who want to minimize the size of the kernel. Reported-by: NIngo Molnar <mingo@kernel.org> Signed-off-by: NH. Peter Anvin <hpa@zytor.com> Cc: Richard Weinberger <richard@nod.at> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
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- 01 5月, 2014 1 次提交
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由 H. Peter Anvin 提交于
The IRET instruction, when returning to a 16-bit segment, only restores the bottom 16 bits of the user space stack pointer. This causes some 16-bit software to break, but it also leaks kernel state to user space. We have a software workaround for that ("espfix") for the 32-bit kernel, but it relies on a nonzero stack segment base which is not available in 64-bit mode. In checkin: b3b42ac2 x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels we "solved" this by forbidding 16-bit segments on 64-bit kernels, with the logic that 16-bit support is crippled on 64-bit kernels anyway (no V86 support), but it turns out that people are doing stuff like running old Win16 binaries under Wine and expect it to work. This works around this by creating percpu "ministacks", each of which is mapped 2^16 times 64K apart. When we detect that the return SS is on the LDT, we copy the IRET frame to the ministack and use the relevant alias to return to userspace. The ministacks are mapped readonly, so if IRET faults we promote #GP to #DF which is an IST vector and thus has its own stack; we then do the fixup in the #DF handler. (Making #GP an IST exception would make the msr_safe functions unsafe in NMI/MC context, and quite possibly have other effects.) Special thanks to: - Andy Lutomirski, for the suggestion of using very small stack slots and copy (as opposed to map) the IRET frame there, and for the suggestion to mark them readonly and let the fault promote to #DF. - Konrad Wilk for paravirt fixup and testing. - Borislav Petkov for testing help and useful comments. Reported-by: NBrian Gerst <brgerst@gmail.com> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andrew Lutomriski <amluto@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dirk Hohndel <dirk@hohndel.org> Cc: Arjan van de Ven <arjan.van.de.ven@intel.com> Cc: comex <comexk@gmail.com> Cc: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: <stable@vger.kernel.org> # consider after upstream merge
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