From 994aeb7a93e43d28f6074195ccb03a384342e1bf Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Wed, 20 Mar 2019 20:34:24 -0400 Subject: sched_domain: Annotate RCU pointers properly The scheduler uses RCU API in various places to access sched_domain pointers. These cause sparse errors as below. Many new errors show up because of an annotation check I added to rcu_assign_pointer(). Let us annotate the pointers correctly which also will help sparse catch any potential future bugs. This fixes the following sparse errors: rt.c:1681:9: error: incompatible types in comparison expression deadline.c:1904:9: error: incompatible types in comparison expression core.c:519:9: error: incompatible types in comparison expression core.c:1634:17: error: incompatible types in comparison expression fair.c:6193:14: error: incompatible types in comparison expression fair.c:9883:22: error: incompatible types in comparison expression fair.c:9897:9: error: incompatible types in comparison expression sched.h:1287:9: error: incompatible types in comparison expression topology.c:612:9: error: incompatible types in comparison expression topology.c:615:9: error: incompatible types in comparison expression sched.h:1300:9: error: incompatible types in comparison expression topology.c:618:9: error: incompatible types in comparison expression sched.h:1287:9: error: incompatible types in comparison expression topology.c:621:9: error: incompatible types in comparison expression sched.h:1300:9: error: incompatible types in comparison expression topology.c:624:9: error: incompatible types in comparison expression topology.c:671:9: error: incompatible types in comparison expression stats.c:45:17: error: incompatible types in comparison expression fair.c:5998:15: error: incompatible types in comparison expression fair.c:5989:15: error: incompatible types in comparison expression fair.c:5998:15: error: incompatible types in comparison expression fair.c:5989:15: error: incompatible types in comparison expression fair.c:6120:19: error: incompatible types in comparison expression fair.c:6506:14: error: incompatible types in comparison expression fair.c:6515:14: error: incompatible types in comparison expression fair.c:6623:9: error: incompatible types in comparison expression fair.c:5970:17: error: incompatible types in comparison expression fair.c:8642:21: error: incompatible types in comparison expression fair.c:9253:9: error: incompatible types in comparison expression fair.c:9331:9: error: incompatible types in comparison expression fair.c:9519:15: error: incompatible types in comparison expression fair.c:9533:14: error: incompatible types in comparison expression fair.c:9542:14: error: incompatible types in comparison expression fair.c:9567:14: error: incompatible types in comparison expression fair.c:9597:14: error: incompatible types in comparison expression fair.c:9421:16: error: incompatible types in comparison expression fair.c:9421:16: error: incompatible types in comparison expression Signed-off-by: Joel Fernandes (Google) Signed-off-by: Peter Zijlstra (Intel) [ From an RCU perspective. ] Reviewed-by: Paul E. McKenney Cc: Josh Triplett Cc: Lai Jiangshan Cc: Linus Torvalds Cc: Luc Van Oostenryck Cc: Mathieu Desnoyers Cc: Mike Galbraith Cc: Morten Rasmussen Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: keescook@chromium.org Cc: kernel-hardening@lists.openwall.com Cc: kernel-team@android.com Link: https://lkml.kernel.org/r/20190321003426.160260-3-joel@joelfernandes.org Signed-off-by: Ingo Molnar --- include/linux/sched/topology.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 57c7ed3fe465..cfc0a89a7159 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -76,8 +76,8 @@ struct sched_domain_shared { struct sched_domain { /* These fields must be setup */ - struct sched_domain *parent; /* top domain must be null terminated */ - struct sched_domain *child; /* bottom domain must be null terminated */ + struct sched_domain __rcu *parent; /* top domain must be null terminated */ + struct sched_domain __rcu *child; /* bottom domain must be null terminated */ struct sched_group *groups; /* the balancing groups of the domain */ unsigned long min_interval; /* Minimum balance interval ms */ unsigned long max_interval; /* Maximum balance interval ms */ -- cgit v1.2.3 From 03f4b48edae7d936c5bf23488c1ce3fbe7fc2733 Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Wed, 20 Mar 2019 20:34:25 -0400 Subject: rcuwait: Annotate task_struct with __rcu This suppresses sparse error generated due to the recently added rcu_assign_pointer sparse check. percpu-rwsem.c:162:9: sparse: error: incompatible types in comparison expression exit.c:316:16: sparse: error: incompatible types in comparison expression Signed-off-by: Joel Fernandes (Google) Signed-off-by: Peter Zijlstra (Intel) [ From an RCU perspective. ] Reviewed-by: Paul E. McKenney Cc: Josh Triplett Cc: Lai Jiangshan Cc: Linus Torvalds Cc: Luc Van Oostenryck Cc: Mathieu Desnoyers Cc: Mike Galbraith Cc: Morten Rasmussen Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: keescook@chromium.org Cc: kernel-hardening@lists.openwall.com Cc: kernel-team@android.com Link: https://lkml.kernel.org/r/20190321003426.160260-4-joel@joelfernandes.org Signed-off-by: Ingo Molnar --- include/linux/rcuwait.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h index 90bfa3279a01..563290fc194f 100644 --- a/include/linux/rcuwait.h +++ b/include/linux/rcuwait.h @@ -18,7 +18,7 @@ * awoken. */ struct rcuwait { - struct task_struct *task; + struct task_struct __rcu *task; }; #define __RCUWAIT_INITIALIZER(name) \ -- cgit v1.2.3 From 2f1a6fbbef7781382850c3104ecb658f21b5d460 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 11 Apr 2019 13:34:45 +1000 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-3-npiggin@gmail.com Signed-off-by: Ingo Molnar --- include/linux/cpu.h | 12 ++++++++++++ kernel/kexec_core.c | 4 ++-- kernel/power/hibernate.c | 12 ++++++------ kernel/power/suspend.c | 4 ++-- 4 files changed, 22 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 5041357d0297..7ab2f09c0a14 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -137,9 +137,21 @@ static inline int disable_nonboot_cpus(void) return freeze_secondary_cpus(0); } extern void enable_nonboot_cpus(void); + +static inline int suspend_disable_secondary_cpus(void) +{ + return freeze_secondary_cpus(0); +} +static inline void suspend_enable_secondary_cpus(void) +{ + return enable_nonboot_cpus(); +} + #else /* !CONFIG_PM_SLEEP_SMP */ static inline int disable_nonboot_cpus(void) { return 0; } static inline void enable_nonboot_cpus(void) {} +static inline int suspend_disable_secondary_cpus(void) { return 0; } +static inline void suspend_enable_secondary_cpus(void) { } #endif /* !CONFIG_PM_SLEEP_SMP */ void cpu_startup_entry(enum cpuhp_state state); diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index d7140447be75..fd5c95ff9251 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1150,7 +1150,7 @@ int kernel_kexec(void) error = dpm_suspend_end(PMSG_FREEZE); if (error) goto Resume_devices; - error = disable_nonboot_cpus(); + error = suspend_disable_secondary_cpus(); if (error) goto Enable_cpus; local_irq_disable(); @@ -1183,7 +1183,7 @@ int kernel_kexec(void) Enable_irqs: local_irq_enable(); Enable_cpus: - enable_nonboot_cpus(); + suspend_enable_secondary_cpus(); dpm_resume_start(PMSG_RESTORE); Resume_devices: dpm_resume_end(PMSG_RESTORE); diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index abef759de7c8..cfc7a57049e4 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -281,7 +281,7 @@ static int create_image(int platform_mode) if (error || hibernation_test(TEST_PLATFORM)) goto Platform_finish; - error = disable_nonboot_cpus(); + error = suspend_disable_secondary_cpus(); if (error || hibernation_test(TEST_CPUS)) goto Enable_cpus; @@ -323,7 +323,7 @@ static int create_image(int platform_mode) local_irq_enable(); Enable_cpus: - enable_nonboot_cpus(); + suspend_enable_secondary_cpus(); Platform_finish: platform_finish(platform_mode); @@ -417,7 +417,7 @@ int hibernation_snapshot(int platform_mode) int __weak hibernate_resume_nonboot_cpu_disable(void) { - return disable_nonboot_cpus(); + return suspend_disable_secondary_cpus(); } /** @@ -486,7 +486,7 @@ static int resume_target_kernel(bool platform_mode) local_irq_enable(); Enable_cpus: - enable_nonboot_cpus(); + suspend_enable_secondary_cpus(); Cleanup: platform_restore_cleanup(platform_mode); @@ -564,7 +564,7 @@ int hibernation_platform_enter(void) if (error) goto Platform_finish; - error = disable_nonboot_cpus(); + error = suspend_disable_secondary_cpus(); if (error) goto Enable_cpus; @@ -586,7 +586,7 @@ int hibernation_platform_enter(void) local_irq_enable(); Enable_cpus: - enable_nonboot_cpus(); + suspend_enable_secondary_cpus(); Platform_finish: hibernation_ops->finish(); diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 0bd595a0b610..59b6def23046 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -428,7 +428,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) if (suspend_test(TEST_PLATFORM)) goto Platform_wake; - error = disable_nonboot_cpus(); + error = suspend_disable_secondary_cpus(); if (error || suspend_test(TEST_CPUS)) goto Enable_cpus; @@ -458,7 +458,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) BUG_ON(irqs_disabled()); Enable_cpus: - enable_nonboot_cpus(); + suspend_enable_secondary_cpus(); Platform_wake: platform_resume_noirq(state); -- cgit v1.2.3 From 9ca12ac04bb7d7cfb28aa549dcd3d15761f15543 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 11 Apr 2019 13:34:46 +1000 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-4-npiggin@gmail.com Signed-off-by: Ingo Molnar --- arch/powerpc/Kconfig | 4 ++++ include/linux/cpu.h | 7 ++++++- kernel/cpu.c | 10 +++++++++- kernel/power/Kconfig | 9 +++++++++ 4 files changed, 28 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 2d0be82c3061..bc98b0e37a10 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -318,6 +318,10 @@ config ARCH_SUSPEND_POSSIBLE (PPC_85xx && !PPC_E500MC) || PPC_86xx || PPC_PSERIES \ || 44x || 40x +config ARCH_SUSPEND_NONZERO_CPU + def_bool y + depends on PPC_POWERNV || PPC_PSERIES + config PPC_DCR_NATIVE bool diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 7ab2f09c0a14..73baab8535c1 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -140,7 +140,12 @@ extern void enable_nonboot_cpus(void); static inline int suspend_disable_secondary_cpus(void) { - return freeze_secondary_cpus(0); + int cpu = 0; + + if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU)) + cpu = -1; + + return freeze_secondary_cpus(cpu); } static inline void suspend_enable_secondary_cpus(void) { diff --git a/kernel/cpu.c b/kernel/cpu.c index 6754f3ecfd94..d1bf6e2b4752 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -1199,8 +1200,15 @@ int freeze_secondary_cpus(int primary) int cpu, error = 0; cpu_maps_update_begin(); - if (!cpu_online(primary)) + if (primary == -1) { primary = cpumask_first(cpu_online_mask); + if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) + primary = housekeeping_any_cpu(HK_FLAG_TIMER); + } else { + if (!cpu_online(primary)) + primary = cpumask_first(cpu_online_mask); + } + /* * We take down all of the non-boot CPUs in one shot to avoid races * with the userspace trying to use the CPU hotplug at the same time diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index f8fe57d1022e..9bbaaab14b36 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -114,6 +114,15 @@ config PM_SLEEP_SMP depends on PM_SLEEP select HOTPLUG_CPU +config PM_SLEEP_SMP_NONZERO_CPU + def_bool y + depends on PM_SLEEP_SMP + depends on ARCH_SUSPEND_NONZERO_CPU + ---help--- + If an arch can suspend (for suspend, hibernate, kexec, etc) on a + non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This + will allow nohz_full mask to include CPU0. + config PM_AUTOSLEEP bool "Opportunistic sleep" depends on PM_SLEEP -- cgit v1.2.3