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3a480d4b |
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05-Jan-2024 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
driver core: cpu: make cpu_subsys const Now that the driver core can properly handle constant struct bus_type, move the cpu_subsys variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Cc: "Rafael J. Wysocki" <rafael@kernel.org> Link: https://lore.kernel.org/r/2024010548-crane-snooze-a871@gregkh Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
8076fcde |
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11-Mar-2024 |
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> |
x86/rfds: Mitigate Register File Data Sampling (RFDS) RFDS is a CPU vulnerability that may allow userspace to infer kernel stale data previously used in floating point registers, vector registers and integer registers. RFDS only affects certain Intel Atom processors. Intel released a microcode update that uses VERW instruction to clear the affected CPU buffers. Unlike MDS, none of the affected cores support SMT. Add RFDS bug infrastructure and enable the VERW based mitigation by default, that clears the affected buffers just before exiting to userspace. Also add sysfs reporting and cmdline parameter "reg_file_data_sampling" to control the mitigation. For details see: Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
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#
2be2a197 |
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29-Feb-2024 |
Thomas Gleixner <tglx@linutronix.de> |
sched/idle: Conditionally handle tick broadcast in default_idle_call() The x86 architecture has an idle routine for AMD CPUs which are affected by erratum 400. On the affected CPUs the local APIC timer stops in the C1E halt state. It therefore requires tick broadcasting. The invocation of tick_broadcast_enter()/exit() from this function violates the RCU constraints because it can end up in lockdep or tracing, which rightfully triggers a warning. tick_broadcast_enter()/exit() must be invoked before ct_cpuidle_enter() and after ct_cpuidle_exit() in default_idle_call(). Add a static branch conditional invocation of tick_broadcast_enter()/exit() into this function to allow X86 to replace the AMD specific idle code. It's guarded by a config switch which will be selected by x86. Otherwise it's a NOOP. Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20240229142248.266708822@linutronix.de
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4c8a4985 |
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27-Feb-2024 |
Ingo Molnar <mingo@kernel.org> |
smp: Avoid 'setup_max_cpus' namespace collision/shadowing bringup_nonboot_cpus() gets passed the 'setup_max_cpus' variable in init/main.c - which is also the name of the parameter, shadowing the name. To reduce confusion and to allow the 'setup_max_cpus' value to be #defined in the <linux/smp.h> header, use the 'max_cpus' name for the function parameter name. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org
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bb5e44fb |
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21-Nov-2023 |
Russell King (Oracle) <rmk+kernel@armlinux.org.uk> |
drivers: base: add arch_cpu_is_hotpluggable() The differences between architecture specific implementations of arch_register_cpu() are down to whether the CPU is hotpluggable or not. Rather than overriding the weak version of arch_register_cpu(), provide a function that can be used to provide this detail instead. Reviewed-by: Shaoqin Huang <shahuang@redhat.com> Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/E1r5R3M-00CszH-6r@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
0949dd96 |
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21-Nov-2023 |
James Morse <james.morse@arm.com> |
drivers: base: Allow parts of GENERIC_CPU_DEVICES to be overridden Architectures often have extra per-cpu work that needs doing before a CPU is registered, often to determine if a CPU is hotpluggable. To allow the ACPI architectures to use GENERIC_CPU_DEVICES, move the cpu_register() call into arch_register_cpu(), which is made __weak so architectures with extra work can override it. This aligns with the way x86, ia64 and loongarch register hotplug CPUs when they become present. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Shaoqin Huang <shahuang@redhat.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/E1r5R3B-00Csz6-Uh@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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6fb45460 |
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09-Jun-2023 |
Peter Zijlstra <peterz@infradead.org> |
sched: Simplify tg_set_cfs_bandwidth() Use guards to reduce gotos and simplify control flow. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
c4dd854f |
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25-Sep-2023 |
Russell King (Oracle) <rmk+kernel@armlinux.org.uk> |
cpu-hotplug: Provide prototypes for arch CPU registration Provide common prototypes for arch_register_cpu() and arch_unregister_cpu(). These are called by acpi_processor.c, with weak versions, so the prototype for this is already set. It is generally not necessary for function prototypes to be conditional on preprocessor macros. Some architectures (e.g. Loongarch) are missing the prototype for this, and rather than add it to Loongarch's asm/cpu.h, do the job once for everyone. Since this covers everyone, remove the now unnecessary prototypes in asm/cpu.h, and therefore remove the 'static' from one of ia64's arch_register_cpu() definitions. [ tglx: Bring back the ia64 part and remove the ACPI prototypes ] Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/E1qkoRr-0088Q8-Da@rmk-PC.armlinux.org.uk
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33af38d8 |
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05-Aug-2023 |
Yue Haibing <yuehaibing@huawei.com> |
cpu/hotplug: Remove unused function declaration cpu_set_state_online() Commit 5356297d12d9 ("cpu/hotplug: Remove cpu_report_state() and related unused cruft") removed function but leave the declaration. Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230805110406.45900-1-yuehaibing@huawei.com
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3f916919 |
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05-Jul-2023 |
Michael Ellerman <mpe@ellerman.id.au> |
cpu/SMT: Move SMT prototypes into cpu_smt.h In order to export the cpuhp_smt_control enum as part of the interface between generic and architecture code, the architecture code needs to include asm/topology.h. But that leads to circular header dependencies. So split the enum and related declarations into a separate header. [ ldufour: Reworded the commit's description ] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20230705145143.40545-3-ldufour@linux.ibm.com
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#
a57c27c7 |
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09-Aug-2023 |
Arnd Bergmann <arnd@arndb.de> |
x86/speculation: Add cpu_show_gds() prototype The newly added function has two definitions but no prototypes: drivers/base/cpu.c:605:16: error: no previous prototype for 'cpu_show_gds' [-Werror=missing-prototypes] Add a declaration next to the other ones for this file to avoid the warning. Fixes: 8974eb588283b ("x86/speculation: Add Gather Data Sampling mitigation") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Daniel Sneddon <daniel.sneddon@linux.intel.com> Cc: stable@kernel.org Link: https://lore.kernel.org/all/20230809130530.1913368-1-arnd%40kernel.org
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#
fb3bd914 |
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28-Jun-2023 |
Borislav Petkov (AMD) <bp@alien8.de> |
x86/srso: Add a Speculative RAS Overflow mitigation Add a mitigation for the speculative return address stack overflow vulnerability found on AMD processors. The mitigation works by ensuring all RET instructions speculate to a controlled location, similar to how speculation is controlled in the retpoline sequence. To accomplish this, the __x86_return_thunk forces the CPU to mispredict every function return using a 'safe return' sequence. To ensure the safety of this mitigation, the kernel must ensure that the safe return sequence is itself free from attacker interference. In Zen3 and Zen4, this is accomplished by creating a BTB alias between the untraining function srso_untrain_ret_alias() and the safe return function srso_safe_ret_alias() which results in evicting a potentially poisoned BTB entry and using that safe one for all function returns. In older Zen1 and Zen2, this is accomplished using a reinterpretation technique similar to Retbleed one: srso_untrain_ret() and srso_safe_ret(). Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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#
7725acaa |
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13-Jun-2023 |
Thomas Gleixner <tglx@linutronix.de> |
init: Provide arch_cpu_finalize_init() check_bugs() has become a dumping ground for all sorts of activities to finalize the CPU initialization before running the rest of the init code. Most are empty, a few do actual bug checks, some do alternative patching and some cobble a CPU advertisement string together.... Aside of that the current implementation requires duplicated function declaration and mostly empty header files for them. Provide a new function arch_cpu_finalize_init(). Provide a generic declaration if CONFIG_ARCH_HAS_CPU_FINALIZE_INIT is selected and a stub inline otherwise. This requires a temporary #ifdef in start_kernel() which will be removed along with check_bugs() once the architectures are converted over. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230613224544.957805717@linutronix.de
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#
bc088f9a |
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12-May-2023 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Remove unused state functions All users converted to the hotplug core mechanism. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205256.972894276@linutronix.de
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#
5356297d |
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12-May-2023 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Remove cpu_report_state() and related unused cruft No more users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205256.582584351@linutronix.de
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#
071c44e4 |
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14-Feb-2023 |
Josh Poimboeuf <jpoimboe@kernel.org> |
sched/idle: Mark arch_cpu_idle_dead() __noreturn Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead() return"), in Xen, when a previously offlined CPU was brought back online, it unexpectedly resumed execution where it left off in the middle of the idle loop. There were some hacks to make that work, but the behavior was surprising as do_idle() doesn't expect an offlined CPU to return from the dead (in arch_cpu_idle_dead()). Now that Xen has been fixed, and the arch-specific implementations of arch_cpu_idle_dead() also don't return, give it a __noreturn attribute. This will cause the compiler to complain if an arch-specific implementation might return. It also improves code generation for both caller and callee. Also fixes the following warning: vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction Reported-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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#
2b5a0e42 |
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12-Jan-2023 |
Peter Zijlstra <peterz@infradead.org> |
objtool/idle: Validate __cpuidle code as noinstr Idle code is very like entry code in that RCU isn't available. As such, add a little validation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.373461409@infradead.org
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#
6b80b59b |
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14-Jun-2022 |
Alexandre Chartre <alexandre.chartre@oracle.com> |
x86/bugs: Report AMD retbleed vulnerability Report that AMD x86 CPUs are vulnerable to the RETBleed (Arbitrary Speculative Code Execution with Return Instructions) attack. [peterz: add hygon] [kim: invert parity; fam15h] Co-developed-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
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#
8d50cdf8 |
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19-May-2022 |
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> |
x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data Add the sysfs reporting file for Processor MMIO Stale Data vulnerability. It exposes the vulnerability and mitigation state similar to the existing files for the other hardware vulnerabilities. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de>
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#
d4e5268a |
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08-Apr-2022 |
Peter Zijlstra <peterz@infradead.org> |
x86,objtool: Mark cpu_startup_entry() __noreturn GCC-8 isn't clever enough to figure out that cpu_start_entry() is a noreturn while objtool is. This results in code after the call in start_secondary(). Give GCC a hand so that they all agree on things. vmlinux.o: warning: objtool: start_secondary()+0x10e: unreachable Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220408094718.383658532@infradead.org
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#
8c854303 |
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03-Aug-2021 |
Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
cpu/hotplug: Remove deprecated CPU-hotplug functions. No users in tree use the deprecated CPU-hotplug functions anymore. Remove them. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210803141621.780504-39-bigeasy@linutronix.de
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#
51f24030 |
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21-Feb-2021 |
Shuo Liu <shuo.a.liu@intel.com> |
cpu/hotplug: Fix build error of using {add,remove}_cpu() with !CONFIG_SMP 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU") introduced {add,remove}_cpu() usage and it hit below error with !CONFIG_SMP: ../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’: ../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration] remove_cpu(cpu); ../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration] add_cpu(cpu); Add add_cpu() function prototypes with !CONFIG_SMP and remove_cpu() with !CONFIG_HOTPLUG_CPU for such usage. Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU") Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Qais Yousef <qais.yousef@arm.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Qais Yousef <qais.yousef@arm.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Signed-off-by: Shuo Liu <shuo.a.liu@intel.com> Link: https://lore.kernel.org/r/20210221134339.57851-1-shuo.a.liu@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
43759fe5 |
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11-Nov-2020 |
Frederic Weisbecker <frederic@kernel.org> |
cpu/hotplug: Add lockdep_is_cpus_held() This commit adds a lockdep_is_cpus_held() function to verify that the proper locks are held and that various operations are running in the correct context. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Neeraj Upadhyay <neeraju@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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#
33def849 |
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21-Oct-2020 |
Joe Perches <joe@perches.com> |
treewide: Convert macro and uses of __section(foo) to __section("foo") Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2accfa69 |
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17-Jun-2020 |
Guenter Roeck <linux@roeck-us.net> |
cpu/speculation: Add prototype for cpu_show_srbds() 0-day is not happy that there is no prototype for cpu_show_srbds(): drivers/base/cpu.c:565:16: error: no previous prototype for 'cpu_show_srbds' Fixes: 7e5b3c267d25 ("x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200617141410.93338-1-linux@roeck-us.net
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fb7fb84a |
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29-Apr-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Remove __freeze_secondary_cpus() The refactored function is no longer required as the codepaths that call freeze_secondary_cpus() are all suspend/resume related now. Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Link: https://lkml.kernel.org/r/20200430114004.17477-2-qais.yousef@arm.com
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#
56555855 |
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29-Apr-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Remove disable_nonboot_cpus() The single user could have called freeze_secondary_cpus() directly. Since this function was a source of confusion, remove it as it's just a pointless wrapper. While at it, rename enable_nonboot_cpus() to thaw_secondary_cpus() to preserve the naming symmetry. Done automatically via: git grep -l enable_nonboot_cpus | xargs sed -i 's/enable_nonboot_cpus/thaw_secondary_cpus/g' Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Link: https://lkml.kernel.org/r/20200430114004.17477-1-qais.yousef@arm.com
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#
e98eac6f |
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26-Mar-2020 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus() A recent change to freeze_secondary_cpus() which added an early abort if a wakeup is pending missed the fact that the function is also invoked for shutdown, reboot and kexec via disable_nonboot_cpus(). In case of disable_nonboot_cpus() the wakeup event needs to be ignored as the purpose is to terminate the currently running kernel. Add a 'suspend' argument which is only set when the freeze is in context of a suspend operation. If not set then an eventually pending wakeup event is ignored. Fixes: a66d955e910a ("cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending") Reported-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Pavankumar Kondeti <pkondeti@codeaurora.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/874kuaxdiz.fsf@nanos.tec.linutronix.de
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#
33c3736e |
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23-Mar-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Hide cpu_up/down() Use separate functions for the device core to bring a CPU up and down. Users outside the device core must use add/remove_cpu() which will take care of extra housekeeping work like keeping sysfs in sync. Make cpu_up/down() static and replace the extra layer of indirection. [ tglx: Removed the extra wrapper functions and adjusted function names ] Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200323135110.30522-18-qais.yousef@arm.com
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#
b99a2659 |
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23-Mar-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Move bringup of secondary CPUs out of smp_init() This is the last direct user of cpu_up() before it can become an internal implementation detail of the cpu subsystem. Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200323135110.30522-17-qais.yousef@arm.com
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#
d720f986 |
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23-Mar-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Provide bringup_hibernate_cpu() arm64 uses cpu_up() in the resume from hibernation code to ensure that the CPU on which the system hibernated is online. Provide a core function for this. [ tglx: Split out from the combo arm64 patch ] Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200323135110.30522-9-qais.yousef@arm.com
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#
0441a559 |
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23-Mar-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Create a new function to shutdown nonboot cpus This function will be used later in machine_shutdown() for some architectures. disable_nonboot_cpus() is not safe to use when doing machine_down(), because it relies on freeze_secondary_cpus() which in turn is a suspend/resume related freeze and could abort if the logic detects any pending activities that can prevent finishing the offlining process. Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200323135110.30522-3-qais.yousef@arm.com
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93ef1429 |
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23-Mar-2020 |
Qais Yousef <qais.yousef@arm.com> |
cpu/hotplug: Add new {add,remove}_cpu() functions The new functions use device_{online,offline}() which are userspace safe. This is in preparation to move cpu_{up, down} kernel users to use a safer interface that is not racy with userspace. Suggested-by: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lkml.kernel.org/r/20200323135110.30522-2-qais.yousef@arm.com
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c55b51a0 |
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16-Nov-2019 |
Daniel Lezcano <daniel.lezcano@linaro.org> |
cpuidle: Allow idle injection to apply exit latency limit In some cases it may be useful to specify an exit latency limit for the idle state to be used during CPU idle time injection. Instead of duplicating the information in struct cpuidle_device or propagating the latency limit in the call stack, replace the use_deepest_state field with forced_latency_limit_ns to represent that limit, so that the deepest idle state with exit latency within that limit is forced (i.e. no governors) when it is set. A zero exit latency limit for forced idle means to use governors in the usual way (analogous to use_deepest_state equal to "false" before this change). Additionally, add play_idle_precise() taking two arguments, the duration of forced idle and the idle state exit latency limit, both in nanoseconds, and redefine play_idle() as a wrapper around that new function. This change is preparatory, no functional impact is expected. Suggested-by: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> [ rjw: Subject, changelog, cpuidle_use_deepest_state() kerneldoc, whitespace ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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731dc9df |
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03-Nov-2019 |
Tyler Hicks <tyhicks@canonical.com> |
cpu/speculation: Uninline and export CPU mitigations helpers A kernel module may need to check the value of the "mitigations=" kernel command line parameter as part of its setup when the module needs to perform software mitigations for a CPU flaw. Uninline and export the helper functions surrounding the cpu_mitigations enum to allow for their usage from a module. Lastly, privatize the enum and cpu_mitigations variable since the value of cpu_mitigations can be checked with the exported helper functions. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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db4d30fb |
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03-Nov-2019 |
Vineela Tummalapalli <vineela.tummalapalli@intel.com> |
x86/bugs: Add ITLB_MULTIHIT bug infrastructure Some processors may incur a machine check error possibly resulting in an unrecoverable CPU lockup when an instruction fetch encounters a TLB multi-hit in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. The relevant erratum can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=205195 There are other processors affected for which the erratum does not fully disclose the impact. This issue affects both bare-metal x86 page tables and EPT. It can be mitigated by either eliminating the use of large pages or by using careful TLB invalidations when changing the page size in the page tables. Just like Spectre, Meltdown, L1TF and MDS, a new bit has been allocated in MSR_IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) and will be set on CPUs which are mitigated against this issue. Signed-off-by: Vineela Tummalapalli <vineela.tummalapalli@intel.com> Co-developed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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6608b45a |
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22-Oct-2019 |
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> |
x86/speculation/taa: Add sysfs reporting for TSX Async Abort Add the sysfs reporting file for TSX Async Abort. It exposes the vulnerability and the mitigation state similar to the existing files for the other hardware vulnerabilities. Sysfs file path is: /sys/devices/system/cpu/vulnerabilities/tsx_async_abort Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Neelima Krishnan <neelima.krishnan@intel.com> Reviewed-by: Mark Gross <mgross@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
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e1572f1d |
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16-Sep-2019 |
Vitaly Kuznetsov <vkuznets@redhat.com> |
cpu/SMT: create and export cpu_smt_possible() KVM needs to know if SMT is theoretically possible, this means it is supported and not forcefully disabled ('nosmt=force'). Create and export cpu_smt_possible() answering this question. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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82e430a6 |
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02-Aug-2019 |
Daniel Lezcano <daniel.lezcano@linaro.org> |
cpuidle: play_idle: Increase the resolution to usec The play_idle resolution is 1ms. The intel_powerclamp bases the idle duration on jiffies. The idle injection API is also using msec based duration but has no user yet. Unfortunately, msec based time does not fit well when we want to inject idle cycle precisely with shallow idle state. In order to set the scene for the incoming idle injection user, move the precision up to usec when calling play_idle. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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#
ec527c31 |
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29-May-2019 |
Jiri Kosina <jkosina@suse.cz> |
x86/power: Fix 'nosmt' vs hibernation triple fault during resume As explained in 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once") we always, no matter what, have to bring up x86 HT siblings during boot at least once in order to avoid first MCE bringing the system to its knees. That means that whenever 'nosmt' is supplied on the kernel command-line, all the HT siblings are as a result sitting in mwait or cpudile after going through the online-offline cycle at least once. This causes a serious issue though when a kernel, which saw 'nosmt' on its commandline, is going to perform resume from hibernation: if the resume from the hibernated image is successful, cr3 is flipped in order to point to the address space of the kernel that is being resumed, which in turn means that all the HT siblings are all of a sudden mwaiting on address which is no longer valid. That results in triple fault shortly after cr3 is switched, and machine reboots. Fix this by always waking up all the SMT siblings before initiating the 'restore from hibernation' process; this guarantees that all the HT siblings will be properly carried over to the resumed kernel waiting in resume_play_dead(), and acted upon accordingly afterwards, based on the target kernel configuration. Symmetricaly, the resumed kernel has to push the SMT siblings to mwait again in case it has SMT disabled; this means it has to online all the siblings when resuming (so that they come out of hlt) and offline them again to let them reach mwait. Cc: 4.19+ <stable@vger.kernel.org> # v4.19+ Debugged-by: Thomas Gleixner <tglx@linutronix.de> Fixes: 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once") Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Pavel Machek <pavel@ucw.cz> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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9ca12ac0 |
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10-Apr-2019 |
Nicholas Piggin <npiggin@gmail.com> |
kernel/cpu: Allow non-zero CPU to be primary for suspend / kexec freeze This patch provides an arch option, ARCH_SUSPEND_NONZERO_CPU, to opt-in to allowing suspend to occur on one of the housekeeping CPUs rather than hardcoded CPU0. This will allow CPU0 to be a nohz_full CPU with a later change. It may be possible for platforms with hardware/firmware restrictions on suspend/wake effectively support this by handing off the final stage to CPU0 when kernel housekeeping is no longer required. Another option is to make housekeeping / nohz_full mask dynamic at runtime, but the complexity could not be justified at this time. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-4-npiggin@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
2f1a6fbb |
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10-Apr-2019 |
Nicholas Piggin <npiggin@gmail.com> |
power/suspend: Add function to disable secondaries for suspend This adds a function to disable secondary CPUs for suspend that are not necessarily non-zero / non-boot CPUs. Platforms will be able to use this to suspend using non-zero CPUs. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-3-npiggin@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
98af8452 |
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12-Apr-2019 |
Josh Poimboeuf <jpoimboe@redhat.com> |
cpu/speculation: Add 'mitigations=' cmdline option Keeping track of the number of mitigations for all the CPU speculation bugs has become overwhelming for many users. It's getting more and more complicated to decide which mitigations are needed for a given architecture. Complicating matters is the fact that each arch tends to have its own custom way to mitigate the same vulnerability. Most users fall into a few basic categories: a) they want all mitigations off; b) they want all reasonable mitigations on, with SMT enabled even if it's vulnerable; or c) they want all reasonable mitigations on, with SMT disabled if vulnerable. Define a set of curated, arch-independent options, each of which is an aggregation of existing options: - mitigations=off: Disable all mitigations. - mitigations=auto: [default] Enable all the default mitigations, but leave SMT enabled, even if it's vulnerable. - mitigations=auto,nosmt: Enable all the default mitigations, disabling SMT if needed by a mitigation. Currently, these options are placeholders which don't actually do anything. They will be fleshed out in upcoming patches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Price <steven.price@arm.com> Cc: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/b07a8ef9b7c5055c3a4637c87d07c296d5016fe0.1555085500.git.jpoimboe@redhat.com
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#
de7b77e5 |
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27-Mar-2019 |
Josh Poimboeuf <jpoimboe@redhat.com> |
cpu/hotplug: Create SMT sysfs interface for all arches Make the /sys/devices/system/cpu/smt/* files available on all arches, so user space has a consistent way to detect whether SMT is enabled. The 'control' file now shows 'notimplemented' for architectures which don't yet have CONFIG_HOTPLUG_SMT. [ tglx: Make notimplemented a real state ] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Waiman Long <longman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Link: https://lkml.kernel.org/r/469c2b98055f2c41e75748e06447d592a64080c9.1553635520.git.jpoimboe@redhat.com
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#
8a4b06d3 |
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18-Feb-2019 |
Thomas Gleixner <tglx@linutronix.de> |
x86/speculation/mds: Add sysfs reporting for MDS Add the sysfs reporting file for MDS. It exposes the vulnerability and mitigation state similar to the existing files for the other speculative hardware vulnerabilities. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com>
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#
b284909a |
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30-Jan-2019 |
Josh Poimboeuf <jpoimboe@redhat.com> |
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM With the following commit: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") ... the hotplug code attempted to detect when SMT was disabled by BIOS, in which case it reported SMT as permanently disabled. However, that code broke a virt hotplug scenario, where the guest is booted with only primary CPU threads, and a sibling is brought online later. The problem is that there doesn't seem to be a way to reliably distinguish between the HW "SMT disabled by BIOS" case and the virt "sibling not yet brought online" case. So the above-mentioned commit was a bit misguided, as it permanently disabled SMT for both cases, preventing future virt sibling hotplugs. Going back and reviewing the original problems which were attempted to be solved by that commit, when SMT was disabled in BIOS: 1) /sys/devices/system/cpu/smt/control showed "on" instead of "notsupported"; and 2) vmx_vm_init() was incorrectly showing the L1TF_MSG_SMT warning. I'd propose that we instead consider #1 above to not actually be a problem. Because, at least in the virt case, it's possible that SMT wasn't disabled by BIOS and a sibling thread could be brought online later. So it makes sense to just always default the smt control to "on" to allow for that possibility (assuming cpuid indicates that the CPU supports SMT). The real problem is #2, which has a simple fix: change vmx_vm_init() to query the actual current SMT state -- i.e., whether any siblings are currently online -- instead of looking at the SMT "control" sysfs value. So fix it by: a) reverting the original "fix" and its followup fix: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") bc2d8d262cba ("cpu/hotplug: Fix SMT supported evaluation") and b) changing vmx_vm_init() to query the actual current SMT state -- instead of the sysfs control value -- to determine whether the L1TF warning is needed. This also requires the 'sched_smt_present' variable to exported, instead of 'cpu_smt_control'. Fixes: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") Reported-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Joe Mario <jmario@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/e3a85d585da28cc333ecbc1e78ee9216e6da9396.1548794349.git.jpoimboe@redhat.com
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b5b1404d |
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12-Aug-2018 |
Linus Torvalds <torvalds@linux-foundation.org> |
init: rename and re-order boot_cpu_state_init() This is purely a preparatory patch for upcoming changes during the 4.19 merge window. We have a function called "boot_cpu_state_init()" that isn't really about the bootup cpu state: that is done much earlier by the similarly named "boot_cpu_init()" (note lack of "state" in name). This function initializes some hotplug CPU state, and needs to run after the percpu data has been properly initialized. It even has a comment to that effect. Except it _doesn't_ actually run after the percpu data has been properly initialized. On x86 it happens to do that, but on at least arm and arm64, the percpu base pointers are initialized by the arch-specific 'smp_prepare_boot_cpu()' hook, which ran _after_ boot_cpu_state_init(). This had some unexpected results, and in particular we have a patch pending for the merge window that did the obvious cleanup of using 'this_cpu_write()' in the cpu hotplug init code: - per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; + this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); which is obviously the right thing to do. Except because of the ordering issue, it actually failed miserably and unexpectedly on arm64. So this just fixes the ordering, and changes the name of the function to be 'boot_cpu_hotplug_init()' to make it obvious that it's about cpu hotplug state, because the core CPU state was supposed to have already been done earlier. Marked for stable, since the (not yet merged) patch that will show this problem is marked for stable. Reported-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bc2d8d26 |
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07-Aug-2018 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Fix SMT supported evaluation Josh reported that the late SMT evaluation in cpu_smt_state_init() sets cpu_smt_control to CPU_SMT_NOT_SUPPORTED in case that 'nosmt' was supplied on the kernel command line as it cannot differentiate between SMT disabled by BIOS and SMT soft disable via 'nosmt'. That wreckages the state and makes the sysfs interface unusable. Rework this so that during bringup of the non boot CPUs the availability of SMT is determined in cpu_smt_allowed(). If a newly booted CPU is not a 'primary' thread then set the local cpu_smt_available marker and evaluate this explicitely right after the initial SMP bringup has finished. SMT evaulation on x86 is a trainwreck as the firmware has all the information _before_ booting the kernel, but there is no interface to query it. Fixes: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") Reported-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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6f4ceee9 |
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24-Jul-2018 |
Waiman Long <longman@redhat.com> |
cpu/hotplug: Add a cpus_read_trylock() function There are use cases where it can be useful to have a cpus_read_trylock() function to work around circular lock dependency problem involving the cpu_hotplug_lock. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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fee0aede |
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13-Jul-2018 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Set CPU_SMT_NOT_SUPPORTED early The CPU_SMT_NOT_SUPPORTED state is set (if the processor does not support SMT) when the sysfs SMT control file is initialized. That was fine so far as this was only required to make the output of the control file correct and to prevent writes in that case. With the upcoming l1tf command line parameter, this needs to be set up before the L1TF mitigation selection and command line parsing happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20180713142323.121795971@linutronix.de
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8e1b706b |
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13-Jul-2018 |
Jiri Kosina <jkosina@suse.cz> |
cpu/hotplug: Expose SMT control init function The L1TF mitigation will gain a commend line parameter which allows to set a combination of hypervisor mitigation and SMT control. Expose cpu_smt_disable() so the command line parser can tweak SMT settings. [ tglx: Split out of larger patch and made it preserve an already existing force off state ] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20180713142323.039715135@linutronix.de
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#
05736e4a |
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29-May-2018 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Provide knobs to control SMT Provide a command line and a sysfs knob to control SMT. The command line options are: 'nosmt': Enumerate secondary threads, but do not online them 'nosmt=force': Ignore secondary threads completely during enumeration via MP table and ACPI/MADT. The sysfs control file has the following states (read/write): 'on': SMT is enabled. Secondary threads can be freely onlined 'off': SMT is disabled. Secondary threads, even if enumerated cannot be onlined 'forceoff': SMT is permanentely disabled. Writes to the control file are rejected. 'notsupported': SMT is not supported by the CPU The command line option 'nosmt' sets the sysfs control to 'off'. This can be changed to 'on' to reenable SMT during runtime. The command line option 'nosmt=force' sets the sysfs control to 'forceoff'. This cannot be changed during runtime. When SMT is 'on' and the control file is changed to 'off' then all online secondary threads are offlined and attempts to online a secondary thread later on are rejected. When SMT is 'off' and the control file is changed to 'on' then secondary threads can be onlined again. The 'off' -> 'on' transition does not automatically online the secondary threads. When the control file is set to 'forceoff', the behaviour is the same as setting it to 'off', but the operation is irreversible and later writes to the control file are rejected. When the control status is 'notsupported' then writes to the control file are rejected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Ingo Molnar <mingo@kernel.org>
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#
17dbca11 |
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13-Jun-2018 |
Andi Kleen <ak@linux.intel.com> |
x86/speculation/l1tf: Add sysfs reporting for l1tf L1TF core kernel workarounds are cheap and normally always enabled, However they still should be reported in sysfs if the system is vulnerable or mitigated. Add the necessary CPU feature/bug bits. - Extend the existing checks for Meltdowns to determine if the system is vulnerable. All CPUs which are not vulnerable to Meltdown are also not vulnerable to L1TF - Check for 32bit non PAE and emit a warning as there is no practical way for mitigation due to the limited physical address bits - If the system has more than MAX_PA/2 physical memory the invert page workarounds don't protect the system against the L1TF attack anymore, because an inverted physical address will also point to valid memory. Print a warning in this case and report that the system is vulnerable. Add a function which returns the PFN limit for the L1TF mitigation, which will be used in follow up patches for sanity and range checks. [ tglx: Renamed the CPU feature bit to L1TF_PTEINV ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Dave Hansen <dave.hansen@intel.com>
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c456442c |
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25-Apr-2018 |
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
x86/bugs: Expose /sys/../spec_store_bypass Add the sysfs file for the new vulerability. It does not do much except show the words 'Vulnerable' for recent x86 cores. Intel cores prior to family 6 are known not to be vulnerable, and so are some Atoms and some Xeon Phi. It assumes that older Cyrix, Centaur, etc. cores are immune. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ingo Molnar <mingo@kernel.org>
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87590ce6 |
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07-Jan-2018 |
Thomas Gleixner <tglx@linutronix.de> |
sysfs/cpu: Add vulnerability folder As the meltdown/spectre problem affects several CPU architectures, it makes sense to have common way to express whether a system is affected by a particular vulnerability or not. If affected the way to express the mitigation should be common as well. Create /sys/devices/system/cpu/vulnerabilities folder and files for meltdown, spectre_v1 and spectre_v2. Allow architectures to override the show function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: David Woodhouse <dwmw@amazon.co.uk> Link: https://lkml.kernel.org/r/20180107214913.096657732@linutronix.de
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f4c09f87 |
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13-Nov-2017 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Get rid of CPU hotplug notifier leftovers The CPU hotplug notifiers are history. Remove the last reminders. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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b2441318 |
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01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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c6cd924e |
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24-Oct-2017 |
Yanjiang Jin <yanjiang.jin@windriver.com> |
cpu/hotplug: Remove obsolete notifier macros commit 530e9b76ae8f ("cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions")' removed the below macros: - #define CPU_UP_CANCELED 0x0004 /* CPU (unsigned)v NOT coming up */ - #define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */ - #define CPU_DOWN_FAILED 0x0006 /* CPU (unsigned)v NOT going down */ But "CPU_UP_CANCELED_FROZEN, CPU_DOWN_PREPARE_FROZEN and CPU_DOWN_FAILED_FROZEN" still refer to them, and nobody uses these "FROZEN" macros now, so remove them too. Signed-off-by: Yanjiang Jin <yanjiang.jin@windriver.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: peterz@infradead.org Cc: bigeasy@linutronix.de Cc: jinyanjiang@gmail.com Link: https://lkml.kernel.org/r/20171024062341.179678-1-yanjiang.jin@windriver.com
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fc8dffd3 |
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24-May-2017 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Convert hotplug locking to percpu rwsem There are no more (known) nested calls to get_online_cpus() and all observed lock ordering problems have been addressed. Replace the magic nested 'rwsem' hackery with a percpu-rwsem. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081549.447014063@linutronix.de
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ade3f680 |
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24-May-2017 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Provide lockdep_assert_cpus_held() Provide a stub function which can be used in places where existing get_online_cpus() calls are moved to call sites. This stub is going to be filled by the final conversion of the hotplug locking mechanism to a percpu rwsem. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081547.161282442@linutronix.de
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8f553c49 |
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24-May-2017 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Provide cpus_read|write_[un]lock() The counting 'rwsem' hackery of get|put_online_cpus() is going to be replaced by percpu rwsem. Rename the functions to make it clear that it's locking and not some refcount style interface. These new functions will be used for the preparatory patches which make the code ready for the percpu rwsem conversion. Rename all instances in the cpu hotplug code while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081547.080397752@linutronix.de
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1777e463 |
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05-Feb-2017 |
Ingo Molnar <mingo@kernel.org> |
sched/headers: Prepare to move _init() prototypes from <linux/sched.h> to <linux/sched/init.h> But first introduce a trivial header and update usage sites. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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530e9b76 |
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21-Dec-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions hotcpu_notifier(), cpu_notifier(), __hotcpu_notifier(), __cpu_notifier(), register_hotcpu_notifier(), register_cpu_notifier(), __register_hotcpu_notifier(), __register_cpu_notifier(), unregister_hotcpu_notifier(), unregister_cpu_notifier(), __unregister_hotcpu_notifier(), __unregister_cpu_notifier() are unused now. Remove them and all related code. Remove also the now pointless cpu notifier error injection mechanism. The states can be executed step by step and error rollback is the same as cpu down, so any state transition can be tested w/o requiring the notifier error injection. Some CPU hotplug states are kept as they are (ab)used for hotplug state tracking. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161221192112.005642358@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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777c6e0d |
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07-Dec-2016 |
Michal Hocko <mhocko@suse.com> |
hotplug: Make register and unregister notifier API symmetric Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its notifiers when HOTPLUG_CPU=y while the registration might succeed even when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap might keep a stale notifier on the list on the manual clean up during the pool tear down and thus corrupt the list. Resulting in the following [ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78 [ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40 <snipped> [ 145.122628] Call Trace: [ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20 [ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400 [ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300 [ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10 [ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30 [ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0 [ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20 [ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0 [ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30 [ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70 [ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180 [ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40 [ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0 [ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0 [ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17 This can be even triggered manually by changing /sys/module/zswap/parameters/compressor multiple times. Fix this issue by making unregister APIs symmetric to the register so there are no surprises. Fixes: 47e627bc8c9a ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU") Reported-and-tested-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Streetman <ddstreet@ieee.org> Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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c1de45ca |
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29-Nov-2016 |
Peter Zijlstra <peterz@infradead.org> |
sched/idle: Add support for tasks that inject idle Idle injection drivers such as Intel powerclamp and ACPI PAD drivers use realtime tasks to take control of CPU then inject idle. There are two issues with this approach: 1. Low efficiency: injected idle task is treated as busy so sched ticks do not stop during injected idle period, the result of these unwanted wakeups can be ~20% loss in power savings. 2. Idle accounting: injected idle time is presented to user as busy. This patch addresses the issues by introducing a new PF_IDLE flag which allows any given task to be treated as idle task while the flag is set. Therefore, idle injection tasks can run through the normal flow of NOHZ idle enter/exit to get the correct accounting as well as tick stop when possible. The implication is that idle task is then no longer limited to PID == 0. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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6727ad9e |
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07-Oct-2016 |
Chris Metcalf <cmetcalf@mellanox.com> |
nmi_backtrace: generate one-line reports for idle cpus When doing an nmi backtrace of many cores, most of which are idle, the output is a little overwhelming and very uninformative. Suppress messages for cpus that are idling when they are interrupted and just emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". We do this by grouping all the cpuidle code together into a new .cpuidle.text section, and then checking the address of the interrupted PC to see if it lies within that section. This commit suitably tags x86 and tile idle routines, and only adds in the minimal framework for other architectures. Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm] Tested-by: Petr Mladek <pmladek@suse.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ee1e714b |
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18-Aug-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Remove CPU_STARTING and CPU_DYING notifier All users are converted to state machine, remove CPU_STARTING and the corresponding CPU_DYING. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160818125731.27256-2-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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d391e552 |
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17-Aug-2016 |
James Morse <james.morse@arm.com> |
cpu/hotplug: Allow suspend/resume CPU to be specified disable_nonboot_cpus() assumes that the lowest numbered online CPU is the boot CPU, and that this is the correct CPU to run any power management code on. On x86 this is always correct, as CPU0 cannot (easily) by taken offline. On arm64 CPU0 can be taken offline. For hibernate/resume this means we may hibernate on a CPU other than CPU0. If the system is rebooted with kexec 'CPU0' will be assigned to a different physical CPU. This complicates hibernate/resume as now we can't trust the CPU numbers. Arch code can find the correct physical CPU, and ensure it is online before resume from hibernate begins, but also needs to influence disable_nonboot_cpus()s choice of CPU. Rename disable_nonboot_cpus() as freeze_secondary_cpus() and add an argument indicating which CPU should be left standing. Follow the logic in migrate_to_reboot_cpu() to use the lowest numbered online CPU if the requested CPU is not online. Add disable_nonboot_cpus() as an inline function that has the existing behaviour. Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
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7ee681b2 |
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13-Jul-2016 |
Thomas Gleixner <tglx@linutronix.de> |
workqueue: Convert to state machine callbacks Get rid of the prio ordering of the separate notifiers and use a proper state callback pair. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153335.197083890@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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89ab9cb1 |
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13-Jul-2016 |
Thomas Gleixner <tglx@linutronix.de> |
perf/core: Remove perf CPU notifier code All users converted to state machine callbacks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153335.115333381@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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f2785ddb |
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09-Mar-2016 |
Thomas Gleixner <tglx@linutronix.de> |
sched/hotplug: Move migration CPU_DYING to sched_cpu_dying() Remove the hotplug notifier and make it an explicit state. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.502222097@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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40190a78 |
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09-Mar-2016 |
Thomas Gleixner <tglx@linutronix.de> |
sched/hotplug: Convert cpu_[in]active notifiers to state machine Now that we reduced everything into single notifiers, it's simple to move them into the hotplug state machine space. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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135fb3e1 |
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09-Mar-2016 |
Thomas Gleixner <tglx@linutronix.de> |
sched: Consolidate the notifier maze We can maintain the ordering of the scheduler cpu hotplug functionality nicely in one notifer. Get rid of the maze. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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27d50c7e |
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26-Feb-2016 |
Thomas Gleixner <tglx@linutronix.de> |
rcu: Make CPU_DYING_IDLE an explicit call Make the RCU CPU_DYING_IDLE callback an explicit function call, so it gets invoked at the proper place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.870167933@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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e69aab13 |
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26-Feb-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Make wait for dead cpu completion based Kill the busy spinning on the control side and just wait for the hotplugged cpu to tell that it reached the dead state. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.776157858@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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931ef163 |
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26-Feb-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Unpark smpboot threads from the state machine Handle the smpboot threads in the state machine. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.295777684@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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cff7d378 |
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26-Feb-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Convert to a state machine for the control processor Move the split out steps into a callback array and let the cpu_up/down code iterate through the array functions. For now most of the callbacks are asymmetric to resemble the current hotplug maze. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182340.671816690@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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090e77c3 |
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26-Feb-2016 |
Thomas Gleixner <tglx@linutronix.de> |
cpu/hotplug: Restructure FROZEN state handling There are only a few callbacks which really care about FROZEN vs. !FROZEN. No need to have extra states for this. Publish the frozen state in an extra variable which is updated under the hotplug lock and let the users interested deal with it w/o imposing that extra state checks on everyone. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182340.334912357@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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02ef3c4a |
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07-Aug-2015 |
Paul E. McKenney <paulmck@kernel.org> |
cpu: Remove try_get_online_cpus() Now that synchronize_sched_expedited() no longer uses it, there are no users of try_get_online_cpus() in mainline. This commit therefore removes it. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de>
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8db14860 |
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17-Jul-2015 |
Nicolas Iooss <nicolas.iooss_linux@m4x.org> |
include, lib: add __printf attributes to several function prototypes Using __printf attributes helps to detect several format string issues at compile time (even though -Wformat-security is currently disabled in Makefile). For example it can detect when formatting a pointer as a number, like the issue fixed in commit a3fa71c40f18 ("wl18xx: show rx_frames_per_rates as an array as it really is"), or when the arguments do not match the format string, c.f. for example commit 5ce1aca81435 ("reiserfs: fix __RASSERT format string"). To prevent similar bugs in the future, add a __printf attribute to every function prototype which needs one in include/linux/ and lib/. These functions were mostly found by using gcc's -Wsuggest-attribute=format flag. Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Felipe Balbi <balbi@ti.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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590ee7db |
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13-Apr-2015 |
Ingo Molnar <mingo@kernel.org> |
cpu: Provide smpboot_thread_init() on !CONFIG_SMP kernels as well Now that we are using smpboot_thread_init() in init/main.c as well, provide it for !CONFIG_SMP as well. This addresses a !CONFIG_SMP build failure. Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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00df35f9 |
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12-Apr-2015 |
Paul E. McKenney <paulmck@kernel.org> |
cpu: Defer smpboot kthread unparking until CPU known to scheduler Currently, smpboot_unpark_threads() is invoked before the incoming CPU has been added to the scheduler's runqueue structures. This might potentially cause the unparked kthread to run on the wrong CPU, since the correct CPU isn't fully set up yet. That causes a sporadic, hard to debug boot crash triggering on some systems, reported by Borislav Petkov, and bisected down to: 2a442c9c6453 ("x86: Use common outgoing-CPU-notification code") This patch places smpboot_unpark_threads() in a CPU hotplug notifier with priority set so that these kthreads are unparked just after the CPU has been added to the runqueues. Reported-and-tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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88428cc5 |
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28-Jan-2015 |
Paul E. McKenney <paulmck@kernel.org> |
rcu: Handle outgoing CPUs on exit from idle loop This commit informs RCU of an outgoing CPU just before that CPU invokes arch_cpu_idle_dead() during its last pass through the idle loop (via a new CPU_DYING_IDLE notifier value). This change means that RCU need not deal with outgoing CPUs passing through the scheduler after informing RCU that they are no longer online. Note that removing the CPU from the rcu_node ->qsmaskinit bit masks is done at CPU_DYING_IDLE time, and orphaning callbacks is still done at CPU_DEAD time, the reason being that at CPU_DEAD time we have another CPU that can adopt them. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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8038dad7 |
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25-Feb-2015 |
Paul E. McKenney <paulmck@kernel.org> |
smpboot: Add common code for notification from dying CPU RCU ignores offlined CPUs, so they cannot safely run RCU read-side code. (They -can- use SRCU, but not RCU.) This means that any use of RCU during or after the call to arch_cpu_idle_dead(). Unfortunately, commit 2ed53c0d6cc99 added a complete() call, which will contain RCU read-side critical sections if there is a task waiting to be awakened. Which, as it turns out, there almost never is. In my qemu/KVM testing, the to-be-awakened task is not yet asleep more than 99.5% of the time. In current mainline, failure is even harder to reproduce, requiring a virtualized environment that delays the outgoing CPU by at least three jiffies between the time it exits its stop_machine() task at CPU_DYING time and the time it calls arch_cpu_idle_dead() from the idle loop. However, this problem really can occur, especially in virtualized environments, and therefore really does need to be fixed This suggests moving back to the polling loop, but using a much shorter wait, with gentle exponential backoff instead of the old 100-millisecond wait. Most of the time, the loop will exit without waiting at all, and almost all of the remaining uses will wait only five microseconds. If the outgoing CPU is preempted, a loop will wait one jiffy, then increase the wait by a factor of 11/10ths, rounding up. As before, there is a five-second timeout. This commit therefore provides common-code infrastructure to do the dying-to-surviving CPU handoff in a safe manner. This code also provides an indication at CPU-online of whether the CPU to be onlined previously timed out on offline. The new cpu_check_up_prepare() function returns -EBUSY if this CPU previously took more than five seconds to go offline, or -EAGAIN if it has not yet managed to go offline. The rationale for -EAGAIN is that it might still be preempted, so an additional wait might well find it correctly offlined. Architecture-specific code can decide how to handle these conditions. Systems in which CPUs take themselves completely offline might respond to an -EBUSY return as if it was a zero (success) return. Systems in which the surviving CPU must take some action might take it at this time, or might simply mark the other CPU as unusable. Note that architectures that take the easy way out and simply pass the -EBUSY and -EAGAIN upwards will change the sysfs API. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: <linux-api@vger.kernel.org> Cc: <linux-arch@vger.kernel.org> [ paulmck: Fixed state machine for architectures that don't check earlier CPU-hotplug results as suggested by James Hogan. ]
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3d52943b |
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30-Sep-2014 |
Sudeep Holla <sudeep.holla@arm.com> |
drivers: base: add cpu_device_create to support per-cpu devices This patch adds a new function to create per-cpu devices. This helps in: 1. reusing the device infrastructure to create any cpu related attributes and corresponding sysfs instead of creating and dealing with raw kobjects directly 2. retaining the legacy path(/sys/devices/system/cpu/..) to support existing sysfs ABI 3. avoiding to create links in the bus directory pointing to the device as there would be per-cpu instance of these devices with the same name since dev->bus is not populated to cpu_sysbus on purpose Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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dd56af42 |
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25-Aug-2014 |
Paul E. McKenney <paulmck@kernel.org> |
rcu: Eliminate deadlock between CPU hotplug and expedited grace periods Currently, the expedited grace-period primitives do get_online_cpus(). This greatly simplifies their implementation, but means that calls to them holding locks that are acquired by CPU-hotplug notifiers (to say nothing of calls to these primitives from CPU-hotplug notifiers) can deadlock. But this is starting to become inconvenient, as can be seen here: https://lkml.org/lkml/2014/8/5/754. The problem in this case is that some developers need to acquire a mutex from a CPU-hotplug notifier, but also need to hold it across a synchronize_rcu_expedited(). As noted above, this currently results in deadlock. This commit avoids the deadlock and retains the simplicity by creating a try_get_online_cpus(), which returns false if the get_online_cpus() reference count could not immediately be incremented. If a call to try_get_online_cpus() returns true, the expedited primitives operate as before. If a call returns false, the expedited primitives fall back to normal grace-period operations. This falling back of course results in increased grace-period latency, but only during times when CPU hotplug operations are actually in flight. The effect should therefore be negligible during normal operation. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Tested-by: Lan Tianyu <tianyu.lan@intel.com>
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ae022622 |
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06-Jun-2014 |
Geert Uytterhoeven <geert+renesas@glider.be> |
idle: remove cpu_idle() forward declarations After all architectures were converted to the generic idle framework, commit d190e8195b90 ("idle: Remove GENERIC_IDLE_LOOP config switch") removed the last caller of cpu_idle(). The forward declarations in header files were forgotten. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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93ae4f97 |
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10-Mar-2014 |
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> |
CPU hotplug: Provide lockless versions of callback registration functions The following method of CPU hotplug callback registration is not safe due to the possibility of an ABBA deadlock involving the cpu_add_remove_lock and the cpu_hotplug.lock. get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); The deadlock is shown below: CPU 0 CPU 1 ----- ----- Acquire cpu_hotplug.lock [via get_online_cpus()] CPU online/offline operation takes cpu_add_remove_lock [via cpu_maps_update_begin()] Try to acquire cpu_add_remove_lock [via register_cpu_notifier()] CPU online/offline operation tries to acquire cpu_hotplug.lock [via cpu_hotplug_begin()] *** DEADLOCK! *** The problem here is that callback registration takes the locks in one order whereas the CPU hotplug operations take the same locks in the opposite order. To avoid this issue and to provide a race-free method to register CPU hotplug callbacks (along with initialization of already online CPUs), introduce new variants of the callback registration APIs that simply register the callbacks without holding the cpu_add_remove_lock during the registration. That way, we can avoid the ABBA scenario. However, we will need to hold the cpu_add_remove_lock throughout the entire critical section, to protect updates to the callback/notifier chain. This can be achieved by writing the callback registration code as follows: cpu_maps_update_begin(); [ or cpu_notifier_register_begin(); see below ] for_each_online_cpu(cpu) init_cpu(cpu); /* This doesn't take the cpu_add_remove_lock */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_maps_update_done(); [ or cpu_notifier_register_done(); see below ] Note that we can't use get_online_cpus() here instead of cpu_maps_update_begin() because the cpu_hotplug.lock is dropped during the invocation of CPU_POST_DEAD notifiers, and hence get_online_cpus() cannot provide the necessary synchronization to protect the callback/notifier chains against concurrent reads and writes. On the other hand, since the cpu_add_remove_lock protects the entire hotplug operation (including CPU_POST_DEAD), we can use cpu_maps_update_begin/done() to guarantee proper synchronization. Also, since cpu_maps_update_begin/done() is like a super-set of get/put_online_cpus(), the former naturally protects the critical sections from concurrent hotplug operations. Since the names cpu_maps_update_begin/done() don't make much sense in CPU hotplug callback registration scenarios, we'll introduce new APIs named cpu_notifier_register_begin/done() and map them to cpu_maps_update_begin/done(). In summary, introduce the lockless variants of un/register_cpu_notifier() and also export the cpu_notifier_register_begin/done() APIs for use by modules. This way, we provide a race-free way to register hotplug callbacks as well as perform initialization for the CPUs that are already online. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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2b9c1f03 |
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08-Feb-2014 |
Ard Biesheuvel <ardb@kernel.org> |
x86: align x86 arch with generic CPU modalias handling The x86 CPU feature modalias handling existed before it was reimplemented generically. This patch aligns the x86 handling so that it (a) reuses some more code that is now generic; (b) uses the generic format for the modalias module metadata entry, i.e., it now uses 'cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:,XXXX,YYYY' instead of the 'x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:,XXXX,YYYY' that was used before. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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d1cb9d1a |
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03-Oct-2013 |
David Miller <davem@davemloft.net> |
of: Make cpu node handling more portable. Use for_each_node_by_type() to iterate all cpu nodes in the system. Provide and overridable function arch_find_n_match_cpu_physical_id, which sees if the given device node matches 'cpu' and if so sets '*thread' when non-NULL to the cpu thread number within the core. The default implementation behaves the same as the existing code. Add a sparc64 implementation. Signed-off-by: David S. Miller <davem@davemloft.net> Tested-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com> Signed-off-by: Grant Likely <grant.likely@linaro.org>
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6dedcca6 |
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25-Sep-2013 |
Toshi Kani <toshi.kani@hp.com> |
hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() cpu_hotplug_driver_lock() serializes CPU online/offline operations when ARCH_CPU_PROBE_RELEASE is set. This lock interface is no longer necessary with the following reason: - lock_device_hotplug() now protects CPU online/offline operations, including the probe & release interfaces enabled by ARCH_CPU_PROBE_RELEASE. The use of cpu_hotplug_driver_lock() is redundant. - cpu_hotplug_driver_lock() is only valid when ARCH_CPU_PROBE_RELEASE is defined, which is misleading and is only enabled on powerpc. This patch removes the cpu_hotplug_driver_lock() interface. As a result, ARCH_CPU_PROBE_RELEASE only enables / disables the cpu probe & release interface as intended. There is no functional change in this patch. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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183912d3 |
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15-Aug-2013 |
Sudeep Holla <sudeep.holla@arm.com> |
of: move of_get_cpu_node implementation to DT core library This patch moves the generalized implementation of of_get_cpu_node from PowerPC to DT core library, thereby adding support for retrieving cpu node for a given logical cpu index on any architecture. The CPU subsystem can now use this function to assign of_node in the cpu device while registering CPUs. It is recommended to use these helper function only in pre-SMP/early initialisation stages to retrieve CPU device node pointers in logical ordering. Once the cpu devices are registered, it can be retrieved easily from cpu device of_node which avoids unnecessary parsing and matching. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Likely <grant.likely@linaro.org> Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
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b9d10be7 |
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12-Aug-2013 |
Toshi Kani <toshi.kani@hp.com> |
ACPI / processor: Acquire writer lock to update CPU maps CPU system maps are protected with reader/writer locks. The reader lock, get_online_cpus(), assures that the maps are not updated while holding the lock. The writer lock, cpu_hotplug_begin(), is used to udpate the cpu maps along with cpu_maps_update_begin(). However, the ACPI processor handler updates the cpu maps without holding the the writer lock. acpi_map_lsapic() is called from acpi_processor_hotadd_init() to update cpu_possible_mask and cpu_present_mask. acpi_unmap_lsapic() is called from acpi_processor_remove() to update cpu_possible_mask. Currently, they are either unprotected or protected with the reader lock, which is not correct. For example, the get_online_cpus() below is supposed to assure that cpu_possible_mask is not changed while the code is iterating with for_each_possible_cpu(). get_online_cpus(); for_each_possible_cpu(cpu) { : } put_online_cpus(); However, this lock has no protection with CPU hotplug since the ACPI processor handler does not use the writer lock when it updates cpu_possible_mask. The reader lock does not serialize within the readers. This patch protects them with the writer lock with cpu_hotplug_begin() along with cpu_maps_update_begin(), which must be held before calling cpu_hotplug_begin(). It also protects arch_register_cpu() / arch_unregister_cpu(), which creates / deletes a sysfs cpu device interface. For this purpose it changes cpu_hotplug_begin() and cpu_hotplug_done() to global and exports them in cpu.h. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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0db0628d |
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19-Jun-2013 |
Paul Gortmaker <paul.gortmaker@windriver.com> |
kernel: delete __cpuinit usage from all core kernel files The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. This removes all the uses of the __cpuinit macros from C files in the core kernel directories (kernel, init, lib, mm, and include) that don't really have a specific maintainer. [1] https://lkml.org/lkml/2013/5/20/589 Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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16e53dbf |
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12-Jun-2013 |
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> |
CPU hotplug: provide a generic helper to disable/enable CPU hotplug There are instances in the kernel where we would like to disable CPU hotplug (from sysfs) during some important operation. Today the freezer code depends on this and the code to do it was kinda tailor-made for that. Restructure the code and make it generic enough to be useful for other usecases too. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Robin Holt <holt@sgi.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Russ Anderson <rja@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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611a75e1 |
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03-May-2013 |
Robert P. J. Day <rpjday@crashcourse.ca> |
include/linux/cpu.h: Update comments to reflect reality Two minor changes to comments: * Remove reference to drivers/base/sys.c, removed in 0a962657. * CPUs are now exported by sysfs via devices/system/cpu. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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d1669912 |
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21-Mar-2013 |
Thomas Gleixner <tglx@linutronix.de> |
idle: Implement generic idle function All idle functions in arch/* are more or less the same, plus minus a few bugs and extra instrumentation, tickless support and other optional items. Implement a generic idle function which resembles the functionality found in arch/. Provide weak arch_cpu_idle_* functions which can be overridden by the architecture code if needed. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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a1a04ec3 |
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21-Mar-2013 |
Thomas Gleixner <tglx@linutronix.de> |
idle: Provide a generic entry point for the idle code For now this calls cpu_idle(), but in the long run we want to move the cpu bringup code to the core and therefor we add a state argument. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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65758202 |
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17-Jul-2012 |
Tejun Heo <tj@kernel.org> |
workqueue: perform cpu down operations from low priority cpu_notifier() Currently, all workqueue cpu hotplug operations run off CPU_PRI_WORKQUEUE which is higher than normal notifiers. This is to ensure that workqueue is up and running while bringing up a CPU before other notifiers try to use workqueue on the CPU. Per-cpu workqueues are supposed to remain working and bound to the CPU for normal CPU_DOWN_PREPARE notifiers. This holds mostly true even with workqueue offlining running with higher priority because workqueue CPU_DOWN_PREPARE only creates a bound trustee thread which runs the per-cpu workqueue without concurrency management without explicitly detaching the existing workers. However, if the trustee needs to create new workers, it creates unbound workers which may wander off to other CPUs while CPU_DOWN_PREPARE notifiers are in progress. Furthermore, if the CPU down is cancelled, the per-CPU workqueue may end up with workers which aren't bound to the CPU. While reliably reproducible with a convoluted artificial test-case involving scheduling and flushing CPU burning work items from CPU down notifiers, this isn't very likely to happen in the wild, and, even when it happens, the effects are likely to be hidden by the following successful CPU down. Fix it by using different priorities for up and down notifiers - high priority for up operations and low priority for down operations. Workqueue cpu hotplug operations will soon go through further cleanup. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
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cb79295e |
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31-May-2012 |
Anton Vorontsov <anton.vorontsov@linaro.org> |
cpu: introduce clear_tasks_mm_cpumask() helper Many architectures clear tasks' mm_cpumask like this: read_lock(&tasklist_lock); for_each_process(p) { if (p->mm) cpumask_clear_cpu(cpu, mm_cpumask(p->mm)); } read_unlock(&tasklist_lock); Depending on the context, the code above may have several problems, such as: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. This patch implements a small helper function that does things correctly, i.e.: 1. We take the task's lock while whe handle its mm (we can't use get_task_mm()/mmput() pair as mmput() might sleep); 2. To catch exited main thread case, we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Also, Per Peter Zijlstra's idea, now we don't grab tasklist_lock in the new helper, instead we take the rcu read lock. We can do this because the function is called after the cpu is taken down and marked offline, so no new tasks will get this cpu set in their mm mask. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Cc: Richard Weinberger <richard@nod.at> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8e7fbcbc |
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09-Jan-2012 |
Peter Zijlstra <peterz@infradead.org> |
sched: Remove stale power aware scheduling remnants and dysfunctional knobs It's been broken forever (i.e. it's not scheduling in a power aware fashion), as reported by Suresh and others sending patches, and nobody cares enough to fix it properly ... so remove it to make space free for something better. There's various problems with the code as it stands today, first and foremost the user interface which is bound to topology levels and has multiple values per level. This results in a state explosion which the administrator or distro needs to master and almost nobody does. Furthermore large configuration state spaces aren't good, it means the thing doesn't just work right because it's either under so many impossibe to meet constraints, or even if there's an achievable state workloads have to be aware of it precisely and can never meet it for dynamic workloads. So pushing this kind of decision to user-space was a bad idea even with a single knob - it's exponentially worse with knobs on every node of the topology. There is a proposal to replace the user interface with a single 3 state knob: sched_balance_policy := { performance, power, auto } where 'auto' would be the preferred default which looks at things like Battery/AC mode and possible cpufreq state or whatever the hw exposes to show us power use expectations - but there's been no progress on it in the past many months. Aside from that, the actual implementation of the various knobs is known to be broken. There have been sporadic attempts at fixing things but these always stop short of reaching a mergable state. Therefore this wholesale removal with the hopes of spurring people who care to come forward once again and work on a coherent replacement. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1326104915.2442.53.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
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313162d0 |
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30-Jan-2012 |
Paul Gortmaker <paul.gortmaker@windriver.com> |
device.h: audit and cleanup users in main include dir The <linux/device.h> header includes a lot of stuff, and it in turn gets a lot of use just for the basic "struct device" which appears so often. Clean up the users as follows: 1) For those headers only needing "struct device" as a pointer in fcn args, replace the include with exactly that. 2) For headers not really using anything from device.h, simply delete the include altogether. 3) For headers relying on getting device.h implicitly before being included themselves, now explicitly include device.h 4) For files in which doing #1 or #2 uncovers an implicit dependency on some other header, fix by explicitly adding the required header(s). Any C files that were implicitly relying on device.h to be present have already been dealt with in advance. Total removals from #1 and #2: 51. Total additions coming from #3: 9. Total other implicit dependencies from #4: 7. As of 3.3-rc1, there were 110, so a net removal of 42 gives about a 38% reduction in device.h presence in include/* Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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fad12ac8 |
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25-Jan-2012 |
Thomas Renninger <trenn@suse.de> |
CPU: Introduce ARCH_HAS_CPU_AUTOPROBE and X86 parts This patch is based on Andi Kleen's work: Implement autoprobing/loading of modules serving CPU specific features (x86cpu autoloading). And Kay Siever's work to get rid of sysdev cpu structures and making use of struct device instead. Before, the cpuid driver had to be loaded to get the x86cpu autoloading feature. With this patch autoloading works through the /sys/devices/system/cpu object Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Dave Jones <davej@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Huang Ying <ying.huang@intel.com> Cc: Len Brown <lenb@kernel.org> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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8a25a2fd |
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21-Dec-2011 |
Kay Sievers <kay.sievers@vrfy.org> |
cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystem This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem and converts the devices to regular devices. The sysdev drivers are implemented as subsystem interfaces now. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Userspace relies on events and generic sysfs subsystem infrastructure from sysdev devices, which are made available with this conversion. Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@amd64.org> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Len Brown <lenb@kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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2987557f |
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03-Dec-2011 |
Josh Triplett <josh@joshtriplett.org> |
driver-core/cpu: Expose hotpluggability to the rest of the kernel When architectures register CPUs, they indicate whether the CPU allows hotplugging; notably, x86 and ARM don't allow hotplugging CPU 0. Userspace can easily query the hotpluggability of a CPU via sysfs; however, the kernel has no convenient way of accessing that property in an architecture-independent way. While the kernel can simply try it and see, some code needs to distinguish between "hotplug failed" and "hotplug has no hope of working on this CPU"; for example, rcutorture's CPU hotplug tests want to avoid drowning out real hotplug failures with expected failures. Expose this property via a new cpu_is_hotpluggable function, so that the rest of the kernel can access it in an architecture-independent way. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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4e71c954 |
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02-Nov-2011 |
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> |
PM / Sleep: Remove unused symbol 'suspend_cpu_hotplug' Remove the suspend_cpu_hotplug declaration, which doesn't correspond to an existing variable. [rjw: Added the changelog.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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80f1ff97 |
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25-Jul-2011 |
Amerigo Wang <amwang@redhat.com> |
notifiers: cpu: move cpu notifiers into cpu.h We presently define all kinds of notifiers in notifier.h. This is not necessary at all, since different subsystems use different notifiers, they are almost non-related with each other. This can also save much build time. Suppose I add a new netdevice event, really I don't have to recompile all the source, just network related. Without this patch, all the source will be recompiled. I move the notify events near to their subsystem notifier registers, so that they can be found more easily. This patch: It is not necessary to share the same notifier.h. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b17cd8d6 |
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07-Nov-2010 |
Brandon Philips <brandon@ifup.org> |
driver core: prune docs about device_interface drivers/base/intf.c was removed before the beginning of (git) time but its Documentation stuck around. Remove it. Signed-off-by: Brandon Philips <brandon@ifup.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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db7bccf4 |
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29-Jun-2010 |
Tejun Heo <tj@kernel.org> |
workqueue: reimplement CPU hotplugging support using trustee Reimplement CPU hotplugging support using trustee thread. On CPU down, a trustee thread is created and each step of CPU down is executed by the trustee and workqueue_cpu_callback() simply drives and waits for trustee state transitions. CPU down operation no longer waits for works to be drained but trustee sticks around till all pending works have been completed. If CPU is brought back up while works are still draining, workqueue_cpu_callback() tells trustee to step down and tell workers to rebind to the cpu. As it's difficult to tell whether cwqs are empty if it's freezing or frozen, trustee doesn't consider draining to be complete while a gcwq is freezing or frozen (tracked by new GCWQ_FREEZING flag). Also, workers which get unbound from their cpu are marked with WORKER_ROGUE. Trustee based implementation doesn't bring any new feature at this point but it will be used to manage worker pool when dynamic shared worker pool is implemented. Signed-off-by: Tejun Heo <tj@kernel.org>
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3a101d05 |
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08-Jun-2010 |
Tejun Heo <tj@kernel.org> |
sched: adjust when cpu_active and cpuset configurations are updated during cpu on/offlining Currently, when a cpu goes down, cpu_active is cleared before CPU_DOWN_PREPARE starts and cpuset configuration is updated from a default priority cpu notifier. When a cpu is coming up, it's set before CPU_ONLINE but cpuset configuration again is updated from the same cpu notifier. For cpu notifiers, this presents an inconsistent state. Threads which a CPU_DOWN_PREPARE notifier expects to be bound to the CPU can be migrated to other cpus because the cpu is no more inactive. Fix it by updating cpu_active in the highest priority cpu notifier and cpuset configuration in the second highest when a cpu is coming up. Down path is updated similarly. This guarantees that all other cpu notifiers see consistent cpu_active and cpuset configuration. cpuset_track_online_cpus() notifier is converted to cpuset_update_active_cpus() which just updates the configuration and now called from cpuset_cpu_[in]active() notifiers registered from sched_init_smp(). If cpuset is disabled, cpuset_update_active_cpus() degenerates into partition_sched_domains() making separate notifier for !CONFIG_CPUSETS unnecessary. This problem is triggered by cmwq. During CPU_DOWN_PREPARE, hotplug callback creates a kthread and kthread_bind()s it to the target cpu, and the thread is expected to run on that cpu. * Ingo's test discovered __cpuinit/exit markups were incorrect. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Menage <menage@google.com>
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50a323b7 |
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08-Jun-2010 |
Tejun Heo <tj@kernel.org> |
sched: define and use CPU_PRI_* enums for cpu notifier priorities Instead of hardcoding priority 10 and 20 in sched and perf, collect them into CPU_PRI_* enums. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
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51badebd |
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26-Nov-2009 |
Gautham R Shenoy <ego@in.ibm.com> |
powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate Currently the cpu-allocation/deallocation process comprises of two steps: - Set the indicators and to update the device tree with DLPAR node information. - Online/offline the allocated/deallocated CPU. This is achieved by writing to the sysfs tunables "probe" during allocation and "release" during deallocation. At the sametime, the userspace can independently online/offline the CPUs of the system using the sysfs tunable "online". It is quite possible that when a userspace tool offlines a CPU for the purpose of deallocation and is in the process of updating the device tree, some other userspace tool could bring the CPU back online by writing to the "online" sysfs tunable thereby causing the deallocate process to fail. The solution to this is to serialize writes to the "probe/release" sysfs tunable with the writes to the "online" sysfs tunable. This patch employs a mutex to provide this serialization, which is a no-op on all architectures except PPC_PSERIES Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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12633e80 |
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25-Nov-2009 |
Nathan Fontenot <nfont@austin.ibm.com> |
sysfs/cpu: Add probe/release files Version 3 of this patch is updated with documentation added to Documentation/ABI. There are no changes to any of the C code from v2 of the patch. In order to support kernel DLPAR of CPU resources we need to provide an interface to add (probe) and remove (release) the resource from the system. This patch Creates new generic probe and release sysfs files to facilitate cpu probe/release. The probe/release interface provides for allowing each arch to supply their own routines for implementing the backend of adding and removing cpus to/from the system. This also creates the powerpc specific stubs to handle the arch callouts from writes to the sysfs files. The creation and use of these files is regulated by the CONFIG_ARCH_CPU_PROBE_RELEASE option so that only architectures that need the capability will have the files created. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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799e64f0 |
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15-Aug-2009 |
Paul E. McKenney <paulmck@kernel.org> |
cpu hotplug: Introduce cpu_notifier() to handle !HOTPLUG_CPU case This patch introduces a new cpu_notifier() API that is similar to hotcpu_notifier(), but which also notifies of CPUs coming online during boot in the !HOTPLUG_CPU case. Reported-by: Ingo Molnar <mingo@elte.hu> Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Tested-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: benh@kernel.crashing.org LKML-Reference: <12503552312611-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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31950eb6 |
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22-Jun-2009 |
Linus Torvalds <torvalds@linux-foundation.org> |
mm/init: cpu_hotplug_init() must be initialized before SLAB SLAB uses get/put_online_cpus() which use a mutex which is itself only initialized when cpu_hotplug_init() is called. Currently we hang suring boot in SLAB due to doing that too late. Reported by James Bottomley and Sachin Sant (and possibly others). Debugged by Benjamin Herrenschmidt. This just removes the dynamic initialization of the data structures, and replaces it with a static one, avoiding this dependency entirely, and removing one unnecessary special initcall. Tested-by: Sachin Sant <sachinp@in.ibm.com> Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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40e8a10d |
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02-Apr-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cpu hotplug: remove unused cpuhotplug_mutex_lock() cpuhotplug_mutex_lock() is not used, remove it. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e545a614 |
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07-Sep-2008 |
Manfred Spraul <manfred@colorfullife.com> |
kernel/cpu.c: create a CPU_STARTING cpu_chain notifier Right now, there is no notifier that is called on a new cpu, before the new cpu begins processing interrupts/softirqs. Various kernel function would need that notification, e.g. kvm works around by calling smp_call_function_single(), rcu polls cpu_online_map. The patch adds a CPU_STARTING notification. It also adds a helper function that sends the message to all cpu_chain handlers. Tested on x86-64. All other archs are untested. Especially on sparc, I'm not sure if I got it right. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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3da1c84c |
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25-Jul-2008 |
Oleg Nesterov <oleg@tv-sign.ru> |
workqueues: make get_online_cpus() useable for work->func() workqueue_cpu_callback(CPU_DEAD) flushes cwq->thread under cpu_maps_update_begin(). This means that the multithreaded workqueues can't use get_online_cpus() due to the possible deadlock, very bad and very old problem. Introduce the new state, CPU_POST_DEAD, which is called after cpu_hotplug_done() but before cpu_maps_update_done(). Change workqueue_cpu_callback() to use CPU_POST_DEAD instead of CPU_DEAD. This means that create/destroy functions can't rely on get_online_cpus() any longer and should take cpu_add_remove_lock instead. [akpm@linux-foundation.org: fix CONFIG_SMP=n] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f718e318 |
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29-Apr-2008 |
Sam Ravnborg <sam@ravnborg.org> |
cpu: fix section mismatch warnings in hotcpu_register Fix following warnings: WARNING: vmlinux.o(.data+0x5020): Section mismatch in reference from the variable cpu_vsyscall_notifier_nb.12876 to the function .cpuinit.text:cpu_vsyscall_notifier() WARNING: vmlinux.o(.data+0x9ce0): Section mismatch in reference from the variable profile_cpu_callback_nb.17654 to the function .devinit.text:profile_cpu_callback() WARNING: vmlinux.o(.data+0xd380): Section mismatch in reference from the variable workqueue_cpu_callback_nb.15004 to the function .devinit.text:workqueue_cpu_callback() WARNING: vmlinux.o(.data+0x11d00): Section mismatch in reference from the variable relay_hotcpu_callback_nb.19626 to the function .cpuinit.text:relay_hotcpu_callback() WARNING: vmlinux.o(.data+0x12970): Section mismatch in reference from the variable cpu_callback_nb.24694 to the function .devinit.text:cpu_callback() WARNING: vmlinux.o(.data+0x3fee0): Section mismatch in reference from the variable percpu_counter_hotcpu_callback_nb.10903 to the function .cpuinit.text:percpu_counter_hotcpu_callback() WARNING: vmlinux.o(.data+0x74ce0): Section mismatch in reference from the variable topology_cpu_callback_nb.12506 to the function .cpuinit.text:topology_cpu_callback() Functions used as argument are by definition only used in HOTPLUG_CPU situations so thay are annotated __cpuinit. Annotate the static variable used by hotcpu_register with __cpuinitdata to match this definition. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5a6483fe |
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26-Feb-2008 |
Matthew Wilcox <willy@infradead.org> |
include: Remove unnecessary inclusions of asm/semaphore.h None of these files use any of the functionality promised by asm/semaphore.h. It's possible that they (or some user of them) rely on it dragging in some unrelated header file, but I can't build all these files, so we'll have to fix any build failures as they come up. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
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d0d23b54 |
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25-Jan-2008 |
Ingo Molnar <mingo@elte.hu> |
cpu-hotplug: fix build on !CONFIG_SMP fix build on !CONFIG_SMP. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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86ef5c9a |
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25-Jan-2008 |
Gautham R Shenoy <ego@in.ibm.com> |
cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus() Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use get_online_cpus and put_online_cpus instead as it highlights the refcount semantics in these operations. The new API guarantees protection against the cpu-hotplug operation, but it doesn't guarantee serialized access to any of the local data structures. Hence the changes needs to be reviewed. In case of pseries_add_processor/pseries_remove_processor, use cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the cpu_present_map there. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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d221938c |
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25-Jan-2008 |
Gautham R Shenoy <ego@in.ibm.com> |
cpu-hotplug: refcount based cpu hotplug This patch implements a Refcount + Waitqueue based model for cpu-hotplug. Now, a thread which wants to prevent cpu-hotplug, will bump up a global refcount and the thread which wants to perform a cpu-hotplug operation will block till the global refcount goes to zero. The readers, if any, during an ongoing cpu-hotplug operation are blocked until the cpu-hotplug operation is over. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Paul Jackson <pj@sgi.com> [For !CONFIG_HOTPLUG_CPU ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
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a263898f |
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30-Dec-2007 |
Ingo Molnar <mingo@elte.hu> |
CPU hotplug: fix cpu_is_offline() on !CONFIG_HOTPLUG_CPU make randconfig bootup testing found that the cpufreq code crashes on bootup, if the powernow-k8 driver is enabled and if maxcpus=1 passed on the boot line to a !CONFIG_HOTPLUG_CPU kernel. First lockdep found out that there's an inconsistent unlock sequence: ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- swapper/1 is trying to release lock (&per_cpu(cpu_policy_rwsem, cpu)) at: [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 but there are no more locks to release! Call Trace: [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 [<ffffffff80251c29>] print_unlock_inbalance_bug+0x104/0x12c [<ffffffff80252f3a>] mark_held_locks+0x56/0x94 [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 [<ffffffff807008b6>] cpufreq_add_dev+0x2a8/0x5c4 ... then shortly afterwards the cpufreq code crashed on an assert: ------------[ cut here ]------------ kernel BUG at drivers/cpufreq/cpufreq.c:1068! invalid opcode: 0000 [1] SMP [...] Call Trace: [<ffffffff805145d6>] sysdev_driver_unregister+0x5b/0x91 [<ffffffff806ff520>] cpufreq_register_driver+0x15d/0x1a2 [<ffffffff80cc0596>] powernowk8_init+0x86/0x94 [...] ---[ end trace 1e9219be2b4431de ]--- the bug was caused by maxcpus=1 bootup, which brought up the secondary core as !cpu_online() but !cpu_is_offline() either, which on on !CONFIG_HOTPLUG_CPU is always 0 (include/linux/cpu.h): /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */ static inline int cpu_is_offline(int cpu) { return 0; } but the cpufreq code uses cpu_online() and cpu_is_offline() in a mixed way - the low-level drivers use cpu_online(), while the cpufreq core uses cpu_is_offline(). This opened up the possibility to add the non-initialized sysdev device of the secondary core: cpufreq-core: trying to register driver powernow-k8 cpufreq-core: adding CPU 0 powernow-k8: BIOS error - no PSB or ACPI _PSS objects cpufreq-core: initialization failed cpufreq-core: adding CPU 1 cpufreq-core: initialization failed which then blew up. The fix is to make cpu_is_offline() always the negation of cpu_online(). With that fix applied the kernel boots up fine without crashing: Calling initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94() powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ processors (1 cpu cores) (version 2.20.00) powernow-k8: BIOS error - no PSB or ACPI _PSS objects initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94() returned -19. initcall 0xffffffff80cc0510 ran for 19 msecs: powernowk8_init+0x0/0x94() Calling initcall 0xffffffff80cc328f: init_lapic_nmi_sysfs+0x0/0x39() We could fix this by making CPU enumeration aware of max_cpus, but that would be more fragile IMO, and the cpu_online(cpu) != cpu_is_offline(cpu) possibility was quite confusing and a continuous source of bugs too. Most distributions have kernels with CPU hotplug enabled, so this bug remained hidden for a long time. Bug forensics: The broken cpu_is_offline() API variant was introduced via: commit a59d2e4e6977e7b94e003c96a41f07e96cddc340 Author: Rusty Russell <rusty@rustcorp.com.au> Date: Mon Mar 8 06:06:03 2004 -0800 [PATCH] minor cleanups for hotplug CPUs ( this predates linux-2.6.git, this commit is available from Thomas's historic git tree. ) Then 1.5 years later the cpufreq code made use of it: commit c32b6b8e524d2c337767d312814484d9289550cf Author: Ashok Raj <ashok.raj@intel.com> Date: Sun Oct 30 14:59:54 2005 -0800 [PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers + if (cpu_is_offline(cpu)) + return 0; which is a correct use of the subtly broken new API. v2.6.15 then shipped with this bug included. then it took two more years for random-kernel qa to hit it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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761bb431 |
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18-Oct-2007 |
Satyam Sharma <satyam@infradead.org> |
Redefine {un}register_hotcpu_notifier() !HOTPLUG_CPU stubs The return of the present "do {} while" based stub definition of register_hotcpu_notifier() cannot be checked. This makes the stub asymmetric w.r.t. the real HOTPLUG_CPU=y implementation that is int-returning. So let us redefine this to be consistent with the full version. Also do the same for unregister_hotcpu_notifier(). We cannot define these as static inline functions due to an existing GCC bug (#33172). So define as macros that return appropriately instead (int '0' for the register_hotcpu_notifier case and void for unregister_hotcpu_notifier). Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f3de4be9 |
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31-Aug-2007 |
Rafael J. Wysocki <rjw@rjwysocki.net> |
PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION Dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION introduced by commit 296699de6bdc717189a331ab6bbe90e05c94db06 "Introduce CONFIG_SUSPEND for suspend-to-Ram and standby" are incorrect, as they don't cover the facts that (1) not all architectures support suspend and (2) SMP hibernation is only possible on X86 and PPC64 (if CONFIG_PPC64_SWSUSP is set). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6707de00 |
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12-Aug-2007 |
Adrian Bunk <bunk@stusta.de> |
sched: make global code static This patch makes the following needlessly global code static: - arch_reinit_sched_domains() - struct attr_sched_mc_power_savings - struct attr_sched_smt_power_savings Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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dcf5008d |
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16-Jul-2007 |
Nathan Lynch <ntl@pobox.com> |
remove unused lock_cpu_hotplug_interruptible definition aa95387774039096c11803c04011f1aa42d85758 removed the implementation of lock_cpu_hotplug_interruptible and all users of it. This stub definition for !CONFIG_HOTPLUG_CPU was left over -- kill it now. Signed-off-by: Nathan Lynch <ntl@pobox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3367b994 |
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08-May-2007 |
Ralf Baechle <ralf@linux-mips.org> |
<linux/sysdev.h> needs to include <linux/module.h> sysdev.h uses THIS_MODULE so should include <linux/module.h>. [akpm@linux-foundation.org: couple of fixes] Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@suse.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1d64b9cb |
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02-Apr-2007 |
Rafael J. Wysocki <rjw@rjwysocki.net> |
[PATCH] Fix microcode-related suspend problem Fix the regression resulting from the recent change of suspend code ordering that causes systems based on Intel x86 CPUs using the microcode driver to hang during the resume. The problem occurs since the microcode driver uses request_firmware() in its CPU hotplug notifier, which is called after tasks has been frozen and hangs. It can be fixed by telling the microcode driver to use the microcode stored in memory during the resume instead of trying to load it from disk. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Adrian Bunk <bunk@stusta.de> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Pavel Machek <pavel@ucw.cz> Cc: Maxim <maximlevitsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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47e627bc |
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12-Feb-2007 |
Avi Kivity <avi@qumranet.com> |
[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU The following patchset allows a host with running virtual machines to be suspended and, on at least a subset of the machines tested, resumed. Note that this is orthogonal to suspending and resuming an individual guest to a file. A side effect of implementing suspend/resume is that cpu hotplug is now supported. This should please the owners of big iron. This patch: KVM wants the cpu hotplug notifications, both for cpu hotplug itself, but more commonly for host suspend/resume. In order to avoid extensive #ifdefs, provide stubs when CONFIG_CPU_HOTPLUG is not defined. In all, we have four cases: - UP: register and unregister stubbed out - SMP+hotplug: full register and unregister - SMP, no hotplug, core: register as __init, unregister stubbed (cpus are brought up during core initialization) - SMP, no hotplug, module: register and unregister stubbed out (cpus cannot be brought up during module lifetime) Signed-off-by: Avi Kivity <avi@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f7dff2b1 |
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06-Dec-2006 |
Gautham R Shenoy <ego@in.ibm.com> |
[PATCH] Handle per-subsystem mutexes for CONFIG_HOTPLUG_CPU not set Provide a common interface for all the subsystems to lock and unlock their per-subsystem hotcpu mutexes. When CONFIG_HOTPLUG_CPU is not set, these operations would be no-ops. [akpm@osdl.org: macros -> inlines] Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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02316067 |
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06-Dec-2006 |
Ingo Molnar <mingo@elte.hu> |
[PATCH] hotplug CPU: clean up hotcpu_notifier() use There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn, prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus generating compiler warnings of unused symbols, hence forcing people to add #ifdefs. the compiler can skip truly unused functions just fine: text data bss dec hex filename 1624412 728710 3674856 6027978 5bfaca vmlinux.before 1624412 728710 3674856 6027978 5bfaca vmlinux.after [akpm@osdl.org: topology.c fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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72486f1f |
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06-Dec-2006 |
Siddha, Suresh B <suresh.b.siddha@intel.com> |
[PATCH] i386: change the 'no_control' field to 'hotpluggable' in the struct cpu Change the 'no_control' field in the cpu struct to a more positive and better term 'hotpluggable'. And change(/cleanup) the logic accordingly. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: "Li, Shaohua" <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
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0344c6c5 |
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24-Oct-2006 |
Christian Krafft <krafft@de.ibm.com> |
[POWERPC] sysfs: add support for adding/removing spu sysfs attributes This patch adds two functions to create and remove sysfs attributes and attribute_group to all cpus. That allows to register sysfs attributes in a subdirectory like: /sys/devices/system/cpu/cpuX/group_name/what_ever This will be used by cbe_thermal to group all attributes dealing with thermal support in one directory. Signed-of-by: Christian Krafft <krafft@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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e3920fb4 |
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26-Sep-2006 |
Rafael J. Wysocki <rjw@rjwysocki.net> |
[PATCH] Disable CPU hotplug during suspend The current suspend code has to be run on one CPU, so we use the CPU hotplug to take the non-boot CPUs offline on SMP machines. However, we should also make sure that these CPUs will not be enabled by someone else after we have disabled them. The functions disable_nonboot_cpus() and enable_nonboot_cpus() are moved to kernel/cpu.c, because they now refer to some stuff in there that should better be static. Also it's better if disable_nonboot_cpus() returns an error instead of panicking if something goes wrong, and enable_nonboot_cpus() has no reason to panic(), because the CPUs may have been enabled by the userland before it tries to take them online. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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aa953877 |
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23-Jul-2006 |
Linus Torvalds <torvalds@macmini.osdl.org> |
cpu hotplug: simplify and hopefully fix locking The CPU hotplug locking was quite messy, with a recursive lock to handle the fact that both the actual up/down sequence wanted to protect itself from being re-entered, but the callbacks that it called also tended to want to protect themselves from CPU events. This splits the lock into two (one to serialize the whole hotplug sequence, the other to protect against the CPU present bitmaps changing). The latter still allows recursive usage because some subsystems (ondemand policy for cpufreq at least) had already gotten too used to the lax locking, but the locking mistakes are hopefully now less fundamental, and we now warn about recursive lock usage when we see it, in the hope that it can be fixed. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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e2c27700 |
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01-Jul-2006 |
Andrew Morton <akpm@osdl.org> |
[PATCH] hotcpu_notifier-fixes Always use do {} while (0). Failing to do so can cause subtle compile failures or bugs. Cc: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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39f4885c |
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27-Jun-2006 |
Chandra Seetharaman <sekharan@us.ibm.com> |
[PATCH] cpu hotplug: add hotplug versions of cpu_notifier Define new macros register_hotcpu_notifier() and unregister_hotcpu_notifier() that redefines register_cpu_notifier() and unregister_cpu_notifier() for use only when HOTPLUG_CPU is defined. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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65edc68c |
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27-Jun-2006 |
Chandra Seetharaman <sekharan@us.ibm.com> |
[PATCH] cpu hotplug: make [un]register_cpu_notifier init time only CPUs come online only at init time (unless CONFIG_HOTPLUG_CPU is defined). So, cpu_notifier functionality need to be available only at init time. This patch makes register_cpu_notifier() available only at init time, unless CONFIG_HOTPLUG_CPU is defined. This patch exports register_cpu_notifier() and unregister_cpu_notifier() only if CONFIG_HOTPLUG_CPU is defined. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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76b67ed9 |
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27-Jun-2006 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
[PATCH] node hotplug: register cpu: remove node struct With Goto-san's patch, we can add new pgdat/node at runtime. I'm now considering node-hot-add with cpu + memory on ACPI. I found acpi container, which describes node, could evaluate cpu before memory. This means cpu-hot-add occurs before memory hot add. In most part, cpu-hot-add doesn't depend on node hot add. But register_cpu(), which creates symbolic link from node to cpu, requires that node should be onlined before register_cpu(). When a node is onlined, its pgdat should be there. This patch-set holds off creating symbolic link from node to cpu until node is onlined. This removes node arguments from register_cpu(). Now, register_cpu() requires 'struct node' as its argument. But the array of struct node is now unified in driver/base/node.c now (By Goto's node hotplug patch). We can get struct node in generic way. So, this argument is not necessary now. This patch also guarantees add cpu under node only when node is onlined. It is necessary for node-hot-add vs. cpu-hot-add patch following this. Moreover, register_cpu calculates cpu->node_id by cpu_to_node() without regard to its 'struct node *root' argument. This patch removes it. Also modify callers of register_cpu()/unregister_cpu, whose args are changed by register-cpu-remove-node-struct patch. [Brice.Goglin@ens-lyon.org: fix it] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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34f361ad |
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25-Mar-2006 |
Ashok Raj <ashok.raj@intel.com> |
[PATCH] Check if cpu can be onlined before calling smp_prepare_cpu() - Moved check for online cpu out of smp_prepare_cpu() - Moved default declaration of smp_prepare_cpu() to kernel/cpu.c - Removed lock_cpu_hotplug() from smp_prepare_cpu() to around it, since its called from cpu_up() as well now. - Removed clearing from cpu_present_map during cpu_offline as it breaks using cpu_up() directly during a subsequent online operation. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: "Li, Shaohua" <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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a29d642a |
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08-Mar-2006 |
Andrew Morton <akpm@osdl.org> |
[PATCH] get_cpu_sysdev() signedness fix Doing (int < NR_CPUS) doesn't dtrt if it's negative.. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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a9d9baa1 |
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28-Nov-2005 |
Ashok Raj <ashok.raj@intel.com> |
[PATCH] clean up lock_cpu_hotplug() in cpufreq There are some callers in cpufreq hotplug notify path that the lowest function calls lock_cpu_hotplug(). The lock is already held during cpu_up() and cpu_down() calls when the notify calls are broadcast to registered clients. Ideally if possible, we could disable_preempt() at the highest caller and make sure we dont sleep in the path down in cpufreq->driver_target() calls but the calls are so intertwined and cumbersome to cleanup. Hence we consistently use lock_cpu_hotplug() and unlock_cpu_hotplug() in all places. - Removed export of cpucontrol semaphore and made it static. - removed explicit uses of up/down with lock_cpu_hotplug() so we can keep track of the the callers in same thread context and just keep refcounts without calling a down() that causes a deadlock. - Removed current_in_hotplug() uses - Removed PF_HOTPLUG_CPU in sched.h introduced for the current_in_hotplug() temporary workaround. Tested with insmod of cpufreq_stat.ko, and logical online/offline to make sure we dont have any hang situations. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: Zwane Mwaikambo <zwane@linuxpower.ca> Cc: Shaohua Li <shaohua.li@intel.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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90d45d17 |
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08-Nov-2005 |
Ashok Raj <ashok.raj@intel.com> |
[PATCH] cpu hotplug: fix locking in cpufreq drivers When calling target drivers to set frequency, we take cpucontrol lock. When we modified the code to accomodate CPU hotplug, there was an attempt to take a double lock of cpucontrol leading to a deadlock. Since the current thread context is already holding the cpucontrol lock, we dont need to make another attempt to acquire it. Now we leave a trace in current->flags indicating current thread already is under cpucontrol lock held, so we dont attempt to do this another time. Thanks to Andrew Morton for the beating:-) From: Brice Goglin <Brice.Goglin@ens-lyon.org> Build fix (akpm: this patch is still unpleasant. Ashok continues to look for a cleaner solution, doesn't he? ;)) Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ad74557a |
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30-Oct-2005 |
Ashok Raj <ashok.raj@intel.com> |
[PATCH] introduce get_cpu_sysdev() to retrieve a sysfs entry for a cpu. Some modules creating sysfs entries under /sys/devices/system/cpu/cpuX/ need to know the parent sysfs entry to make devices under them. This will just return the sysfs entry for a given cpu. sysfs entries showing under each cpu sysfs can be easily created if such entries can be created by registering a sysfs driver for cpuclass. The issue is when the entry is created the CPU may not be online, hence we would need to defer the creation until the online notification comes. Current users: cache entries for Intel CPU's and cpufreq subsystem. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Zwane Mwaikambo <zwane@holomorphy.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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d51fe1be |
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02-Sep-2005 |
Rolf Eike Beer <eike-kernel@sf-tec.de> |
[PATCH] remove driverfs references from include/linux/cpu.h and net/sunrpc/rpc_pipe.c This patch is against 2.6.10, but still applies cleanly. It's just s/driverfs/sysfs/ in these two files. Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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52a119fe |
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25-Jun-2005 |
Ashok Raj <ashok.raj@intel.com> |
[PATCH] make smp_prepare_cpu to a weak function I really wish smp_prepare_cpu() would disappear eventually. In the interim this is ideally a weak function, so we dont end up changing several places to define this dummy in headers. Today since the dummy declaration is done only in drivers/base/cpu.c but the function is called in kernel/power/smp.c i get undefined reference in my cpu hotplug code for x86_64 under development. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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1da177e4 |
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16-Apr-2005 |
Linus Torvalds <torvalds@ppc970.osdl.org> |
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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