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

diff --git a/include/linux/sched/idle.h b/include/linux/sched/idle.h
index d73d314..478084f 100644 (file)
--- a/include/linux/sched/idle.h
+++ b/include/linux/sched/idle.h
@@ -23,12 +23,37 @@ static inline void wake_up_if_idle(int cpu) { }
  */
 #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();
 
@@ -41,12 +66,7 @@ static inline bool __must_check current_set_polling_and_test(void)
        return unlikely(tif_need_resched());
 }
 
-static inline void __current_clr_polling(void)
-{
-       clear_thread_flag(TIF_POLLING_NRFLAG);
-}
-
-static inline bool __must_check current_clr_polling_and_test(void)
+static __always_inline bool __must_check current_clr_polling_and_test(void)
 {
        __current_clr_polling();
 
@@ -73,7 +93,7 @@ static inline bool __must_check current_clr_polling_and_test(void)
 }
 #endif
 
-static inline void current_clr_polling(void)
+static __always_inline void current_clr_polling(void)
 {
        __current_clr_polling();
 

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 9f392ec..c026468 100644 (file)
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -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)
 #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
 static inline int arch_within_stack_frames(const void * const stack,