powerpc/traps: unrecoverable_exception() is not an interrupt handler

unrecoverable_exception() is called from interrupt handlers or
after an interrupt handler has failed.

Make it a standard function to avoid doubling the actions
performed on interrupt entry (e.g.: user time accounting).

Fixes: 3a96570f ("powerpc: convert interrupt handlers to use wrappers")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ae96c59fa2cb7f24a8929c58cfa2c909cb8ff1f1.1615291471.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/interrupt.h

@@ -410,7 +410,6 @@ DECLARE_INTERRUPT_HANDLER(altivec_assist_exception);
 DECLARE_INTERRUPT_HANDLER(CacheLockingException);
 DECLARE_INTERRUPT_HANDLER(SPEFloatingPointException);
 DECLARE_INTERRUPT_HANDLER(SPEFloatingPointRoundException);
-DECLARE_INTERRUPT_HANDLER(unrecoverable_exception);
 DECLARE_INTERRUPT_HANDLER(WatchdogException);
 DECLARE_INTERRUPT_HANDLER(kernel_bad_stack);
 
@@ -437,6 +436,8 @@ DECLARE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode);
 
 DECLARE_INTERRUPT_HANDLER_ASYNC(TAUException);
 
+void unrecoverable_exception(struct pt_regs *regs);
+
 void replay_system_reset(void);
 void replay_soft_interrupts(void);
 

arch/powerpc/kernel/interrupt.c

@@ -436,7 +436,6 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	return ret;
 }
 
-void unrecoverable_exception(struct pt_regs *regs);
 void preempt_schedule_irq(void);
 
 notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsigned long msr)

arch/powerpc/kernel/traps.c

@@ -2170,7 +2170,7 @@ DEFINE_INTERRUPT_HANDLER(SPEFloatingPointRoundException)
  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
  * we therefore lost state by taking this exception.
  */
-DEFINE_INTERRUPT_HANDLER(unrecoverable_exception)
+void unrecoverable_exception(struct pt_regs *regs)
 {
 	pr_emerg("Unrecoverable exception %lx at %lx (msr=%lx)\n",
 		 regs->trap, regs->nip, regs->msr);