Commit e4df1511 authored Jan 12, 2023 by Peter Zijlstra Committed by Ingo Molnar Jan 13, 2023

cpuidle, sched: Remove instrumentation from TIF_{POLLING_NRFLAG,NEED_RESCHED}

objtool pointed out that various idle-TIF management methods
have instrumentation:

vmlinux.o: warning: objtool: mwait_idle+0x5: call to current_set_polling_and_test() leaves .noinstr.text section
vmlinux.o: warning: objtool: acpi_processor_ffh_cstate_enter+0xc5: call to current_set_polling_and_test() leaves .noinstr.text section
vmlinux.o: warning: objtool: cpu_idle_poll.isra.0+0x73: call to test_ti_thread_flag() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle+0xbc: call to current_set_polling_and_test() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_irq+0xea: call to current_set_polling_and_test() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_s2idle+0xb4: call to current_set_polling_and_test() leaves .noinstr.text section

vmlinux.o: warning: objtool: intel_idle+0xa6: call to current_clr_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_irq+0xbf: call to current_clr_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_s2idle+0xa1: call to current_clr_polling() leaves .noinstr.text section

vmlinux.o: warning: objtool: mwait_idle+0xe: call to __current_set_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: acpi_processor_ffh_cstate_enter+0xc5: call to __current_set_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: cpu_idle_poll.isra.0+0x73: call to test_ti_thread_flag() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle+0xbc: call to __current_set_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_irq+0xea: call to __current_set_polling() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_s2idle+0xb4: call to __current_set_polling() leaves .noinstr.text section

vmlinux.o: warning: objtool: cpu_idle_poll.isra.0+0x73: call to test_ti_thread_flag() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_s2idle+0x73: call to test_ti_thread_flag.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_irq+0x91: call to test_ti_thread_flag.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle+0x78: call to test_ti_thread_flag.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: acpi_safe_halt+0xf: call to test_ti_thread_flag.constprop.0() leaves .noinstr.text section

Remove the instrumentation, because these methods are used in low-level
cpuidle code moving between states, that should not be instrumented.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.988741683@infradead.org

parent e3ee5e66

include/linux/sched/idle.h

+30 −10

Original line number	Original line	Diff line number	Diff line
	@@ -23,12 +23,37 @@ static inline void wake_up_if_idle(int cpu) { }
	*/		*/
	#ifdef TIF_POLLING_NRFLAG		#ifdef TIF_POLLING_NRFLAG

	static inline void __current_set_polling(void)		#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H

			static __always_inline void __current_set_polling(void)
	{		{
	set_thread_flag(TIF_POLLING_NRFLAG);		arch_set_bit(TIF_POLLING_NRFLAG,
			(unsigned long *)(&current_thread_info()->flags));
	}		}

	static inline bool __must_check current_set_polling_and_test(void)		static __always_inline void __current_clr_polling(void)
			{
			arch_clear_bit(TIF_POLLING_NRFLAG,
			(unsigned long *)(&current_thread_info()->flags));
			}

			#else

			static __always_inline void __current_set_polling(void)
			{
			set_bit(TIF_POLLING_NRFLAG,
			(unsigned long *)(&current_thread_info()->flags));
			}

			static __always_inline void __current_clr_polling(void)
			{
			clear_bit(TIF_POLLING_NRFLAG,
			(unsigned long *)(&current_thread_info()->flags));
			}

			#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */

			static __always_inline bool __must_check current_set_polling_and_test(void)
	{		{
	__current_set_polling();		__current_set_polling();

	@@ -41,12 +66,7 @@ static inline bool __must_check current_set_polling_and_test(void)
	return unlikely(tif_need_resched());		return unlikely(tif_need_resched());
	}		}

	static inline void __current_clr_polling(void)		static __always_inline bool __must_check current_clr_polling_and_test(void)
	{
	clear_thread_flag(TIF_POLLING_NRFLAG);
	}

	static inline bool __must_check current_clr_polling_and_test(void)
	{		{
	__current_clr_polling();		__current_clr_polling();

	@@ -73,7 +93,7 @@ static inline bool __must_check current_clr_polling_and_test(void)
	}		}
	#endif		#endif

	static inline void current_clr_polling(void)		static __always_inline void current_clr_polling(void)
	{		{
	__current_clr_polling();		__current_clr_polling();

include/linux/thread_info.h

+17 −1

Original line number	Original line	Diff line number	Diff line
	@@ -177,7 +177,23 @@ static __always_inline unsigned long read_ti_thread_flags(struct thread_info *ti
	clear_ti_thread_flag(task_thread_info(t), TIF_##fl)		clear_ti_thread_flag(task_thread_info(t), TIF_##fl)
	#endif /* !CONFIG_GENERIC_ENTRY */		#endif /* !CONFIG_GENERIC_ENTRY */

	#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)		#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H

			static __always_inline bool tif_need_resched(void)
			{
			return arch_test_bit(TIF_NEED_RESCHED,
			(unsigned long *)(&current_thread_info()->flags));
			}

			#else

			static __always_inline bool tif_need_resched(void)
			{
			return test_bit(TIF_NEED_RESCHED,
			(unsigned long *)(&current_thread_info()->flags));
			}

			#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */

	#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES		#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
	static inline int arch_within_stack_frames(const void * const stack,		static inline int arch_within_stack_frames(const void * const stack,