powerpc: Disable interrupts early in Program Check

Program Check exceptions are the result of WARNs, BUGs, some type of breakpoints, kprobe, and other illegal instructions.

We want interrupts (and thus preemption) to remain disabled while doing the initial stage of testing the reason and branching off to a debugger or kprobe, so we are still on the original CPU which makes debugging easier in various cases.

This is how the code was intended, hence the local_irq_enable() right in the middle of program_check_exception().

However, the assembly exception prologue for that exception was incorrectly marked as enabling interrupts, which defeats that (and records a redundant enable with lockdep).

---
 arch/powerpc/kernel/exceptions-64s.S |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index d4be7bb..3844ca7 100644
@@ -775,7 +775,7 @@ program_check_common:
 	EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN)
 	bl	.save_nvgprs
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	ENABLE_INTS
+	DISABLE_INTS
 	bl	.program_check_exception
 	b	.ret_from_except