diff options
Diffstat (limited to 'kernel/context_tracking.c')
| -rw-r--r-- | kernel/context_tracking.c | 59 |
1 files changed, 39 insertions, 20 deletions
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 937ecdfdf258..72d59a1a6eb6 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c | |||
| @@ -39,15 +39,15 @@ void context_tracking_cpu_set(int cpu) | |||
| 39 | } | 39 | } |
| 40 | 40 | ||
| 41 | /** | 41 | /** |
| 42 | * context_tracking_user_enter - Inform the context tracking that the CPU is going to | 42 | * context_tracking_enter - Inform the context tracking that the CPU is going |
| 43 | * enter userspace mode. | 43 | * enter user or guest space mode. |
| 44 | * | 44 | * |
| 45 | * This function must be called right before we switch from the kernel | 45 | * This function must be called right before we switch from the kernel |
| 46 | * to userspace, when it's guaranteed the remaining kernel instructions | 46 | * to user or guest space, when it's guaranteed the remaining kernel |
| 47 | * to execute won't use any RCU read side critical section because this | 47 | * instructions to execute won't use any RCU read side critical section |
| 48 | * function sets RCU in extended quiescent state. | 48 | * because this function sets RCU in extended quiescent state. |
| 49 | */ | 49 | */ |
| 50 | void context_tracking_user_enter(void) | 50 | void context_tracking_enter(enum ctx_state state) |
| 51 | { | 51 | { |
| 52 | unsigned long flags; | 52 | unsigned long flags; |
| 53 | 53 | ||
| @@ -75,9 +75,8 @@ void context_tracking_user_enter(void) | |||
| 75 | WARN_ON_ONCE(!current->mm); | 75 | WARN_ON_ONCE(!current->mm); |
| 76 | 76 | ||
| 77 | local_irq_save(flags); | 77 | local_irq_save(flags); |
| 78 | if ( __this_cpu_read(context_tracking.state) != IN_USER) { | 78 | if ( __this_cpu_read(context_tracking.state) != state) { |
| 79 | if (__this_cpu_read(context_tracking.active)) { | 79 | if (__this_cpu_read(context_tracking.active)) { |
| 80 | trace_user_enter(0); | ||
| 81 | /* | 80 | /* |
| 82 | * At this stage, only low level arch entry code remains and | 81 | * At this stage, only low level arch entry code remains and |
| 83 | * then we'll run in userspace. We can assume there won't be | 82 | * then we'll run in userspace. We can assume there won't be |
| @@ -85,7 +84,10 @@ void context_tracking_user_enter(void) | |||
| 85 | * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency | 84 | * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency |
| 86 | * on the tick. | 85 | * on the tick. |
| 87 | */ | 86 | */ |
| 88 | vtime_user_enter(current); | 87 | if (state == CONTEXT_USER) { |
| 88 | trace_user_enter(0); | ||
| 89 | vtime_user_enter(current); | ||
| 90 | } | ||
| 89 | rcu_user_enter(); | 91 | rcu_user_enter(); |
| 90 | } | 92 | } |
| 91 | /* | 93 | /* |
| @@ -101,24 +103,32 @@ void context_tracking_user_enter(void) | |||
| 101 | * OTOH we can spare the calls to vtime and RCU when context_tracking.active | 103 | * OTOH we can spare the calls to vtime and RCU when context_tracking.active |
| 102 | * is false because we know that CPU is not tickless. | 104 | * is false because we know that CPU is not tickless. |
| 103 | */ | 105 | */ |
| 104 | __this_cpu_write(context_tracking.state, IN_USER); | 106 | __this_cpu_write(context_tracking.state, state); |
| 105 | } | 107 | } |
| 106 | local_irq_restore(flags); | 108 | local_irq_restore(flags); |
| 107 | } | 109 | } |
| 110 | NOKPROBE_SYMBOL(context_tracking_enter); | ||
| 111 | EXPORT_SYMBOL_GPL(context_tracking_enter); | ||
| 112 | |||
| 113 | void context_tracking_user_enter(void) | ||
| 114 | { | ||
| 115 | context_tracking_enter(CONTEXT_USER); | ||
| 116 | } | ||
| 108 | NOKPROBE_SYMBOL(context_tracking_user_enter); | 117 | NOKPROBE_SYMBOL(context_tracking_user_enter); |
| 109 | 118 | ||
| 110 | /** | 119 | /** |
| 111 | * context_tracking_user_exit - Inform the context tracking that the CPU is | 120 | * context_tracking_exit - Inform the context tracking that the CPU is |
| 112 | * exiting userspace mode and entering the kernel. | 121 | * exiting user or guest mode and entering the kernel. |
| 113 | * | 122 | * |
| 114 | * This function must be called after we entered the kernel from userspace | 123 | * This function must be called after we entered the kernel from user or |
| 115 | * before any use of RCU read side critical section. This potentially include | 124 | * guest space before any use of RCU read side critical section. This |
| 116 | * any high level kernel code like syscalls, exceptions, signal handling, etc... | 125 | * potentially include any high level kernel code like syscalls, exceptions, |
| 126 | * signal handling, etc... | ||
| 117 | * | 127 | * |
| 118 | * This call supports re-entrancy. This way it can be called from any exception | 128 | * This call supports re-entrancy. This way it can be called from any exception |
| 119 | * handler without needing to know if we came from userspace or not. | 129 | * handler without needing to know if we came from userspace or not. |
| 120 | */ | 130 | */ |
| 121 | void context_tracking_user_exit(void) | 131 | void context_tracking_exit(enum ctx_state state) |
| 122 | { | 132 | { |
| 123 | unsigned long flags; | 133 | unsigned long flags; |
| 124 | 134 | ||
| @@ -129,20 +139,29 @@ void context_tracking_user_exit(void) | |||
| 129 | return; | 139 | return; |
| 130 | 140 | ||
| 131 | local_irq_save(flags); | 141 | local_irq_save(flags); |
| 132 | if (__this_cpu_read(context_tracking.state) == IN_USER) { | 142 | if (__this_cpu_read(context_tracking.state) == state) { |
| 133 | if (__this_cpu_read(context_tracking.active)) { | 143 | if (__this_cpu_read(context_tracking.active)) { |
| 134 | /* | 144 | /* |
| 135 | * We are going to run code that may use RCU. Inform | 145 | * We are going to run code that may use RCU. Inform |
| 136 | * RCU core about that (ie: we may need the tick again). | 146 | * RCU core about that (ie: we may need the tick again). |
| 137 | */ | 147 | */ |
| 138 | rcu_user_exit(); | 148 | rcu_user_exit(); |
| 139 | vtime_user_exit(current); | 149 | if (state == CONTEXT_USER) { |
| 140 | trace_user_exit(0); | 150 | vtime_user_exit(current); |
| 151 | trace_user_exit(0); | ||
| 152 | } | ||
| 141 | } | 153 | } |
| 142 | __this_cpu_write(context_tracking.state, IN_KERNEL); | 154 | __this_cpu_write(context_tracking.state, CONTEXT_KERNEL); |
| 143 | } | 155 | } |
| 144 | local_irq_restore(flags); | 156 | local_irq_restore(flags); |
| 145 | } | 157 | } |
| 158 | NOKPROBE_SYMBOL(context_tracking_exit); | ||
| 159 | EXPORT_SYMBOL_GPL(context_tracking_exit); | ||
| 160 | |||
| 161 | void context_tracking_user_exit(void) | ||
| 162 | { | ||
| 163 | context_tracking_exit(CONTEXT_USER); | ||
| 164 | } | ||
| 146 | NOKPROBE_SYMBOL(context_tracking_user_exit); | 165 | NOKPROBE_SYMBOL(context_tracking_user_exit); |
| 147 | 166 | ||
| 148 | /** | 167 | /** |
