powerpc/irq: Make alignment & program interrupt behave the same

Alignment was the last user of the ENABLE_INTS macro, which we can
now remove. All non-syscall exceptions now disable interrupts on
entry, they get re-enabled conditionally from C code. Don't
unconditionally re-enable in program check either, check the
original context.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/exception-64s.h

@@ -288,13 +288,6 @@ label##_hv:								\
 /* Exception addition: Hard disable interrupts */
 #define DISABLE_INTS	SOFT_DISABLE_INTS(r10,r11)
 
-/* Exception addition: Keep interrupt state */
-#define ENABLE_INTS				\
-	ld	r11,PACAKMSR(r13);		\
-	ld	r12,_MSR(r1);			\
-	rlwimi	r11,r12,0,MSR_EE;		\
-	mtmsrd	r11,1
-
 #define ADD_NVGPRS				\
 	bl	.save_nvgprs
 

arch/powerpc/kernel/exceptions-64s.S

@@ -768,8 +768,8 @@ alignment_common:
 	std	r3,_DAR(r1)
 	std	r4,_DSISR(r1)
 	bl	.save_nvgprs
+	DISABLE_INTS
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	ENABLE_INTS
 	bl	.alignment_exception
 	b	.ret_from_except
 

arch/powerpc/kernel/traps.c

@@ -248,7 +248,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 				   addr, regs->nip, regs->link, code);
 	}
 
-	if (!arch_irq_disabled_regs(regs))
+	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
 		local_irq_enable();
 
 	memset(&info, 0, sizeof(info));
@@ -1019,7 +1019,9 @@ void __kprobes program_check_exception(struct pt_regs *regs)
 		return;
 	}
 
-	local_irq_enable();
+	/* We restore the interrupt state now */
+	if (!arch_irq_disabled_regs(regs))
+		local_irq_enable();
 
 #ifdef CONFIG_MATH_EMULATION
 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
@@ -1069,6 +1071,10 @@ void alignment_exception(struct pt_regs *regs)
 {
 	int sig, code, fixed = 0;
 
+	/* We restore the interrupt state now */
+	if (!arch_irq_disabled_regs(regs))
+		local_irq_enable();
+
 	/* we don't implement logging of alignment exceptions */
 	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
 		fixed = fix_alignment(regs);