The following commit has been merged into the sched/core branch of tip: Commit-ID: 2c9a98d3bc808717ab63ad928a2b568967775388 Gitweb: https://git.kernel.org/tip/2c9a98d3bc808717ab63ad928a2b568967775388 Author: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> AuthorDate: Mon, 18 Jan 2021 15:12:21 +01:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Wed, 17 Feb 2021 14:12:42 +01:00 preempt/dynamic: Provide preempt_schedule[_notrace]() static calls 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: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20210118141223.123667-7-frederic@xxxxxxxxxx --- arch/x86/include/asm/preempt.h | 34 +++++++++++++++++++++++++-------- kernel/sched/core.c | 12 ++++++++++++- 2 files changed, 38 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index 69485ca..9b12dce 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -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_thunk(void); -# define __preempt_schedule() \ - asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT) - extern asmlinkage void preempt_schedule(void); - extern asmlinkage void preempt_schedule_notrace_thunk(void); -# define __preempt_schedule_notrace() \ - asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT) +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() \ +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_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() \ +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 */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f7c8fd8..880611c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5265,6 +5265,12 @@ 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 * @@ -5317,6 +5323,12 @@ 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 */ /*
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