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sched: Harden PREEMPT_DYNAMIC 

Use the new EXPORT_STATIC_CALL_TRAMP() / static_call_mod() to unexport
the static_call_key for the PREEMPT_DYNAMIC calls such that modules
can no longer update these calls.

Having modules change/hi-jack the preemption calls would be horrible.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
master
Peter Zijlstra 2021-01-25 16:26:50 +01:00 committed by Ingo Molnar
parent 73f44fe19d
commit ef72661e28
4 changed files with 8 additions and 8 deletions
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4
arch/x86/include/asm/preempt.h
View File

@ -114,7 +114,7 @@ DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);
#define __preempt_schedule() \
do { \
__ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule)); \
__STATIC_CALL_MOD_ADDRESSABLE(preempt_schedule); \
asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \
} while (0)
@ -127,7 +127,7 @@ DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);
#define __preempt_schedule_notrace() \
do { \
__ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule_notrace)); \
__STATIC_CALL_MOD_ADDRESSABLE(preempt_schedule_notrace); \
asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule_notrace) : ASM_CALL_CONSTRAINT); \
} while (0)

2
include/linux/kernel.h
View File

@ -93,7 +93,7 @@ DECLARE_STATIC_CALL(might_resched, __cond_resched);
static __always_inline void might_resched(void)
{
static_call(might_resched)();
static_call_mod(might_resched)();
}
#else

2
include/linux/sched.h
View File

@ -1880,7 +1880,7 @@ DECLARE_STATIC_CALL(cond_resched, __cond_resched);
static __always_inline int _cond_resched(void)
{
return static_call(cond_resched)();
return static_call_mod(cond_resched)();
}
#else

8
kernel/sched/core.c
View File

@ -5267,7 +5267,7 @@ EXPORT_SYMBOL(preempt_schedule);
#ifdef CONFIG_PREEMPT_DYNAMIC
DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);
EXPORT_STATIC_CALL(preempt_schedule);
EXPORT_STATIC_CALL_TRAMP(preempt_schedule);
#endif
@ -5325,7 +5325,7 @@ EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
#ifdef CONFIG_PREEMPT_DYNAMIC
DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);
EXPORT_STATIC_CALL(preempt_schedule_notrace);
EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace);
#endif
#endif /* CONFIG_PREEMPTION */
@ -6997,10 +6997,10 @@ EXPORT_SYMBOL(__cond_resched);
#ifdef CONFIG_PREEMPT_DYNAMIC
DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched);
EXPORT_STATIC_CALL(cond_resched);
EXPORT_STATIC_CALL_TRAMP(cond_resched);
DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched);
EXPORT_STATIC_CALL(might_resched);
EXPORT_STATIC_CALL_TRAMP(might_resched);
#endif
/*