From: Andi Kleen <ak@suse.de>
Date: Fri, 19 Oct 2007 18:35:03 +0000 (+0200)
Subject: x86: use raw locks during oopses
X-Git-Tag: firefly_0821_release~24748^2~8
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=39743c9ef717fd4f2b5583f010115c5f2482b8ae;p=firefly-linux-kernel-4.4.55.git

x86: use raw locks during oopses

Don't want any lockdep or other fragile machinery to run during oopses.
Use raw spinlocks directly for oops locking.
Also disables irq flag tracing there.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 746fad2c504f..3f02e0f42e6a 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -350,11 +350,11 @@ int is_valid_bugaddr(unsigned long eip)
 void die(const char * str, struct pt_regs * regs, long err)
 {
 	static struct {
-		spinlock_t lock;
+		raw_spinlock_t lock;
 		u32 lock_owner;
 		int lock_owner_depth;
 	} die = {
-		.lock =			__SPIN_LOCK_UNLOCKED(die.lock),
+		.lock =			__RAW_SPIN_LOCK_UNLOCKED,
 		.lock_owner =		-1,
 		.lock_owner_depth =	0
 	};
@@ -365,13 +365,14 @@ void die(const char * str, struct pt_regs * regs, long err)
 
 	if (die.lock_owner != raw_smp_processor_id()) {
 		console_verbose();
-		spin_lock_irqsave(&die.lock, flags);
+		__raw_spin_lock(&die.lock);
+		raw_local_save_flags(flags);
 		die.lock_owner = smp_processor_id();
 		die.lock_owner_depth = 0;
 		bust_spinlocks(1);
 	}
 	else
-		local_save_flags(flags);
+		raw_local_save_flags(flags);
 
 	if (++die.lock_owner_depth < 3) {
 		unsigned long esp;
@@ -415,7 +416,8 @@ void die(const char * str, struct pt_regs * regs, long err)
 	bust_spinlocks(0);
 	die.lock_owner = -1;
 	add_taint(TAINT_DIE);
-	spin_unlock_irqrestore(&die.lock, flags);
+	__raw_spin_unlock(&die.lock);
+	raw_local_irq_restore(flags);
 
 	if (!regs)
 		return;
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index b4a9b3db1994..df690c3fa458 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -462,7 +462,7 @@ void out_of_line_bug(void)
 EXPORT_SYMBOL(out_of_line_bug);
 #endif
 
-static DEFINE_SPINLOCK(die_lock);
+static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
 static int die_owner = -1;
 static unsigned int die_nest_count;
 
@@ -474,13 +474,13 @@ unsigned __kprobes long oops_begin(void)
 	oops_enter();
 
 	/* racy, but better than risking deadlock. */
-	local_irq_save(flags);
+	raw_local_irq_save(flags);
 	cpu = smp_processor_id();
-	if (!spin_trylock(&die_lock)) { 
+	if (!__raw_spin_trylock(&die_lock)) {
 		if (cpu == die_owner) 
 			/* nested oops. should stop eventually */;
 		else
-			spin_lock(&die_lock);
+			__raw_spin_lock(&die_lock);
 	}
 	die_nest_count++;
 	die_owner = cpu;
@@ -494,12 +494,10 @@ void __kprobes oops_end(unsigned long flags)
 	die_owner = -1;
 	bust_spinlocks(0);
 	die_nest_count--;
-	if (die_nest_count)
-		/* We still own the lock */
-		local_irq_restore(flags);
-	else
+	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */
-		spin_unlock_irqrestore(&die_lock, flags);
+		__raw_spin_unlock(&die_lock);
+	raw_local_irq_restore(flags);
 	if (panic_on_oops)
 		panic("Fatal exception");
 	oops_exit();