[ARM] traps: don't call undef hook functions with spinlock held

Calling the undefined instruction handler functions with a
spinlock held is a recipe for must_sleep() warnings.  Avoid it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 18 insertions, 13 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 7277aef83098..872f1f8fbb57 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -288,14 +288,28 @@ void unregister_undef_hook(struct undef_hook *hook)
         spin_unlock_irqrestore(&undef_lock, flags);
 }
 
+static int call_undef_hook(struct pt_regs *regs, unsigned int instr)
+{
+        struct undef_hook *hook;
+        unsigned long flags;
+        int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
+
+        spin_lock_irqsave(&undef_lock, flags);
+        list_for_each_entry(hook, &undef_hook, node)
+                if ((instr & hook->instr_mask) == hook->instr_val &&
+                    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
+                        fn = hook->fn;
+        spin_unlock_irqrestore(&undef_lock, flags);
+
+        return fn ? fn(regs, instr) : 1;
+}
+
 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 {
         unsigned int correction = thumb_mode(regs) ? 2 : 4;
         unsigned int instr;
-        struct undef_hook *hook;
         siginfo_t info;
         void __user *pc;
-        unsigned long flags;
 
         /*
          * According to the ARM ARM, PC is 2 or 4 bytes ahead,
@@ -325,17 +339,8 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
         }
 #endif
 
-        spin_lock_irqsave(&undef_lock, flags);
-        list_for_each_entry(hook, &undef_hook, node) {
-                if ((instr & hook->instr_mask) == hook->instr_val &&
-                    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
-                        if (hook->fn(regs, instr) == 0) {
-                                spin_unlock_irqrestore(&undef_lock, flags);
-                                return;
-                        }
-                }
-        }
-        spin_unlock_irqrestore(&undef_lock, flags);
+        if (call_undef_hook(regs, instr) == 0)
+                return;
 
 #ifdef CONFIG_DEBUG_USER
         if (user_debug & UDBG_UNDEFINED) {