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 ++++++++++++ 1 file changed, 12 insertions(+) (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); -- 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 --- include/linux/cpu.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include') 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) { -- cgit v1.2.3