Commit 7508f768 authored by Peter Zijlstra (Intel)'s avatar Peter Zijlstra (Intel) Committed by Zheng Zengkai
Browse files

preempt/dynamic: Provide preempt_schedule[_notrace]() static calls 

mainline inclusion
from mainline-5.12-rc1
commit 2c9a98d3
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I410UT
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2c9a98d3bc808717ab63ad928a2b568967775388



---------------------------

Provide static calls to control preempt_schedule[_notrace]()
(called in CONFIG_PREEMPT) so that we can override their behaviour when
preempt= is overriden.

Since the default behaviour is full preemption, both their calls are
initialized to the arch provided wrapper, if any.

[fweisbec: only define static calls when PREEMPT_DYNAMIC, make it less
           dependent on x86 with __preempt_schedule_func]
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210118141223.123667-7-frederic@kernel.org


Signed-off-by: default avatarMa Junhai <majunhai2@huawei.com>
Reviewed-by: default avatarChen Hui <judy.chenhui@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 9253d578

arch/x86/include/asm/preempt.h

+26 −8
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <asm/rmwcc.h>

#include <asm/percpu.h>

#include <linux/thread_info.h>

#include <linux/static_call_types.h>



DECLARE_PER_CPU(int, __preempt_count);
@@ -103,16 +104,33 @@ static __always_inline bool should_resched(int preempt_offset) 
}



#ifdef CONFIG_PREEMPTION



extern asmlinkage void preempt_schedule(void);

extern asmlinkage void preempt_schedule_thunk(void);



#define __preempt_schedule_func preempt_schedule_thunk



DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);



#define __preempt_schedule() \

	asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT)

do { \

	__ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule)); \

	asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \

} while (0)



  extern asmlinkage void preempt_schedule(void);

extern asmlinkage void preempt_schedule_notrace(void);

extern asmlinkage void preempt_schedule_notrace_thunk(void);



#define __preempt_schedule_notrace_func preempt_schedule_notrace_thunk



DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);



#define __preempt_schedule_notrace() \

	asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT)

do { \

	__ADDRESSABLE(STATIC_CALL_KEY(preempt_schedule_notrace)); \

	asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule_notrace) : ASM_CALL_CONSTRAINT); \

} while (0)



  extern asmlinkage void preempt_schedule_notrace(void);

#endif



#endif /* __ASM_PREEMPT_H */

kernel/sched/core.c

+12 −0
Original line number Diff line number Diff line
@@ -4703,6 +4703,12 @@ asmlinkage __visible void __sched notrace preempt_schedule(void) 
NOKPROBE_SYMBOL(preempt_schedule);

EXPORT_SYMBOL(preempt_schedule);



#ifdef CONFIG_PREEMPT_DYNAMIC

DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);

EXPORT_STATIC_CALL(preempt_schedule);

#endif





/**

 * preempt_schedule_notrace - preempt_schedule called by tracing

 *
@@ -4755,6 +4761,12 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) 
}

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);

#endif





#endif /* CONFIG_PREEMPTION */



/*