From 3e00189de00fbca49c2ac3ffd68ee43a03716dcd Mon Sep 17 00:00:00 2001
From: Masamichi Takagi <masamichi.takagi@riken.jp>
Date: Tue, 9 Mar 2021 12:14:55 +0900
Subject: [PATCH] kprintf: fix checking if interrupt is disabled

Change-Id: I2ee1a1e2438ae761c4136593953ede2738bc6f74
---
 arch/arm64/kernel/cpu.c  | 14 ++++++++++++--
 arch/x86_64/kernel/cpu.c |  9 +++++++++
 kernel/debug.c           |  6 +++---
 lib/include/ihk/cpu.h    |  2 --
 4 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/cpu.c b/arch/arm64/kernel/cpu.c
index fb7664c2..b407e28c 100644
--- a/arch/arm64/kernel/cpu.c
+++ b/arch/arm64/kernel/cpu.c
@@ -912,7 +912,6 @@ unsigned long cpu_enable_interrupt_save(void)
 	return flags;
 }
 
-#ifdef ENABLE_FUGAKU_HACKS
 int cpu_interrupt_disabled(void)
 {
 	unsigned long flags;
@@ -925,7 +924,6 @@ int cpu_interrupt_disabled(void)
 		: "memory");
 	return (flags == masked);
 }
-#endif
 
 #else /* defined(CONFIG_HAS_NMI) */
 
@@ -989,6 +987,18 @@ unsigned long cpu_enable_interrupt_save(void)
 		: "memory");
 	return flags;
 }
+
+int cpu_interrupt_disabled(void)
+{
+	unsigned long flags;
+
+	asm volatile(
+		"mrs    %0, daif	// arch_local_irq_save\n"
+		: "=r" (flags)
+		:
+		: "memory");
+	return !!(flags & 0x2);
+}
 #endif /* defined(CONFIG_HAS_NMI) */
 
 /* we not have "pause" instruction, instead "yield" instruction */
diff --git a/arch/x86_64/kernel/cpu.c b/arch/x86_64/kernel/cpu.c
index fbd0b826..5591a2e3 100644
--- a/arch/x86_64/kernel/cpu.c
+++ b/arch/x86_64/kernel/cpu.c
@@ -1273,6 +1273,15 @@ unsigned long cpu_enable_interrupt_save(void)
 	return flags;
 }
 
+int cpu_interrupt_disabled(void)
+{
+	unsigned long flags;
+
+	asm volatile("pushf; pop %0" : "=r"(flags) : : "memory", "cc");
+
+	return !(flags & 0x200);
+}
+
 /*@
   @ behavior valid_vector:
   @   assumes 32 <= vector <= 255;
diff --git a/kernel/debug.c b/kernel/debug.c
index 93a16368..54835a1e 100644
--- a/kernel/debug.c
+++ b/kernel/debug.c
@@ -87,7 +87,7 @@ void kputs(char *buf)
 	debug_spin_unlock_irqrestore(&kmsg_buf->lock, flags_inner);
 	kprintf_unlock(flags_outer);
 
-	if (irqflags_can_interrupt(flags_outer) &&
+	if (!cpu_interrupt_disabled() &&
 			DEBUG_KMSG_USED > IHK_KMSG_HIGH_WATER_MARK) {
 		eventfd(IHK_OS_EVENTFD_TYPE_KMSG);
 		ihk_mc_delay_us(IHK_KMSG_NOTIFY_DELAY);
@@ -128,7 +128,7 @@ int __kprintf(const char *format, ...)
 	}
 
 	debug_spin_unlock_irqrestore(&kmsg_buf->lock, flags_inner);
-	if (irqflags_can_interrupt(flags_inner) &&
+	if (!cpu_interrupt_disabled() &&
 			DEBUG_KMSG_USED > IHK_KMSG_HIGH_WATER_MARK) {
 		eventfd(IHK_OS_EVENTFD_TYPE_KMSG);
 		ihk_mc_delay_us(IHK_KMSG_NOTIFY_DELAY);
@@ -171,7 +171,7 @@ int kprintf(const char *format, ...)
 	debug_spin_unlock_irqrestore(&kmsg_buf->lock, flags_inner);
 	kprintf_unlock(flags_outer);
 
-	if (irqflags_can_interrupt(flags_outer) &&
+	if (!cpu_interrupt_disabled() &&
 			DEBUG_KMSG_USED > IHK_KMSG_HIGH_WATER_MARK) {
 		eventfd(IHK_OS_EVENTFD_TYPE_KMSG);
 		ihk_mc_delay_us(IHK_KMSG_NOTIFY_DELAY);
diff --git a/lib/include/ihk/cpu.h b/lib/include/ihk/cpu.h
index b141a45c..a283e094 100644
--- a/lib/include/ihk/cpu.h
+++ b/lib/include/ihk/cpu.h
@@ -23,9 +23,7 @@ extern int num_processors;
 
 void cpu_enable_interrupt(void);
 void cpu_disable_interrupt(void);
-#ifdef ENABLE_FUGAKU_HACKS
 int cpu_interrupt_disabled(void);
-#endif
 void cpu_halt(void);
 #ifdef ENABLE_FUGAKU_HACKS
 void cpu_halt_panic(void);