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Subject[PATCH 1/6] rcu,nohz: add state parameter to context_tracking_user_enter/exit
Date
From: Rik van Riel <riel@redhat.com>

Add the expected ctx_state as a parameter to context_tracking_user_enter
and context_tracking_user_exit, allowing the same functions to not just
track kernel <> user space switching, but also kernel <> guest transitions.

Catalin, Will: this patch and the next one break ARM, entry.S needs to be
modified to add the IN_USER parameter to context_tracking_enter & _exit.

Cc: catalin.marinas@arm.com
Cc: will.deacon@arm.com
Signed-off-by: Rik van Riel <riel@redhat.com>
---
include/linux/context_tracking.h | 12 ++++++------
kernel/context_tracking.c | 10 +++++-----
2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 37b81bd51ec0..bd9f000fc98d 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -10,21 +10,21 @@
#ifdef CONFIG_CONTEXT_TRACKING
extern void context_tracking_cpu_set(int cpu);

-extern void context_tracking_user_enter(void);
-extern void context_tracking_user_exit(void);
+extern void context_tracking_user_enter(enum ctx_state state);
+extern void context_tracking_user_exit(enum ctx_state state);
extern void __context_tracking_task_switch(struct task_struct *prev,
struct task_struct *next);

static inline void user_enter(void)
{
if (context_tracking_is_enabled())
- context_tracking_user_enter();
+ context_tracking_user_enter(IN_USER);

}
static inline void user_exit(void)
{
if (context_tracking_is_enabled())
- context_tracking_user_exit();
+ context_tracking_user_exit(IN_USER);
}

static inline enum ctx_state exception_enter(void)
@@ -35,7 +35,7 @@ static inline enum ctx_state exception_enter(void)
return 0;

prev_ctx = this_cpu_read(context_tracking.state);
- context_tracking_user_exit();
+ context_tracking_user_exit(prev_ctx);

return prev_ctx;
}
@@ -44,7 +44,7 @@ static inline void exception_exit(enum ctx_state prev_ctx)
{
if (context_tracking_is_enabled()) {
if (prev_ctx == IN_USER)
- context_tracking_user_enter();
+ context_tracking_user_enter(prev_ctx);
}
}

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 937ecdfdf258..4c010787c9ec 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -47,7 +47,7 @@ void context_tracking_cpu_set(int cpu)
* to execute won't use any RCU read side critical section because this
* function sets RCU in extended quiescent state.
*/
-void context_tracking_user_enter(void)
+void context_tracking_user_enter(enum ctx_state state)
{
unsigned long flags;

@@ -75,7 +75,7 @@ void context_tracking_user_enter(void)
WARN_ON_ONCE(!current->mm);

local_irq_save(flags);
- if ( __this_cpu_read(context_tracking.state) != IN_USER) {
+ if ( __this_cpu_read(context_tracking.state) != state) {
if (__this_cpu_read(context_tracking.active)) {
trace_user_enter(0);
/*
@@ -101,7 +101,7 @@ void context_tracking_user_enter(void)
* OTOH we can spare the calls to vtime and RCU when context_tracking.active
* is false because we know that CPU is not tickless.
*/
- __this_cpu_write(context_tracking.state, IN_USER);
+ __this_cpu_write(context_tracking.state, state);
}
local_irq_restore(flags);
}
@@ -118,7 +118,7 @@ NOKPROBE_SYMBOL(context_tracking_user_enter);
* This call supports re-entrancy. This way it can be called from any exception
* handler without needing to know if we came from userspace or not.
*/
-void context_tracking_user_exit(void)
+void context_tracking_user_exit(enum ctx_state state)
{
unsigned long flags;

@@ -129,7 +129,7 @@ void context_tracking_user_exit(void)
return;

local_irq_save(flags);
- if (__this_cpu_read(context_tracking.state) == IN_USER) {
+ if (__this_cpu_read(context_tracking.state) == state) {
if (__this_cpu_read(context_tracking.active)) {
/*
* We are going to run code that may use RCU. Inform
--
1.9.3


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