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static_call: Add call depth tracking support

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When indirect calls are switched to direct calls then it has to be ensured
that the call target is not the function, but the call thunk when call
depth tracking is enabled. But static calls are available before call
thunks have been set up.

Ensure a second run through the static call patching code after call thunks
have been created. When call thunks are not enabled this has no side
effects.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.306100465@infradead.org
This commit is contained in:
Peter Zijlstra
2022-09-15 13:11:31 +02:00
parent f5c1bb2afe
commit 7825451fa4
5 changed files with 44 additions and 5 deletions
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23
kernel/static_call_inline.c
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@@ -15,7 +15,18 @@ extern struct static_call_site __start_static_call_sites[],
extern struct static_call_tramp_key __start_static_call_tramp_key[],
__stop_static_call_tramp_key[];
static bool static_call_initialized;
static int static_call_initialized;
/*
* Must be called before early_initcall() to be effective.
*/
void static_call_force_reinit(void)
{
if (WARN_ON_ONCE(!static_call_initialized))
return;
static_call_initialized++;
}
/* mutex to protect key modules/sites */
static DEFINE_MUTEX(static_call_mutex);
@@ -475,7 +486,8 @@ int __init static_call_init(void)
{
int ret;
if (static_call_initialized)
/* See static_call_force_reinit(). */
if (static_call_initialized == 1)
return 0;
cpus_read_lock();
@@ -490,11 +502,12 @@ int __init static_call_init(void)
BUG();
}
static_call_initialized = true;
#ifdef CONFIG_MODULES
register_module_notifier(&static_call_module_nb);
if (!static_call_initialized)
register_module_notifier(&static_call_module_nb);
#endif
static_call_initialized = 1;
return 0;
}
early_initcall(static_call_init);