ARM: entry: avoid enabling interrupts in prefetch/data abort handlers

Avoid enabling interrupts if the parent context had interrupts enabled
in the abort handler assembly code, and move this into the breakpoint/
page/alignment fault handlers instead.

This gets rid of some special-casing for the breakpoint fault handlers
from the low level abort handler path.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/alignment.c

@@ -727,6 +727,9 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	int isize = 4;
 	int thumb2_32b = 0;
 
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	instrptr = instruction_pointer(regs);
 
 	fs = get_fs();

arch/arm/mm/fault.c

@@ -285,6 +285,10 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	tsk = current;
 	mm  = tsk->mm;
 
+	/* Enable interrupts if they were enabled in the parent context. */
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..