arm64: entry: make NMI entry/exit functions static

Now that we only call arm64_enter_nmi() and arm64_exit_nmi() from within
entry-common.c, let's make these static to ensure this remains the case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210607094624.34689-19-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/exception.h

@@ -57,8 +57,6 @@ asmlinkage void call_on_irq_stack(struct pt_regs *regs,
 				  void (*func)(struct pt_regs *));
 asmlinkage void enter_from_user_mode(void);
 asmlinkage void exit_to_user_mode(void);
-void arm64_enter_nmi(struct pt_regs *regs);
-void arm64_exit_nmi(struct pt_regs *regs);
 void do_mem_abort(unsigned long far, unsigned int esr, struct pt_regs *regs);
 void do_undefinstr(struct pt_regs *regs);
 void do_bti(struct pt_regs *regs);

arch/arm64/kernel/entry-common.c

@@ -75,7 +75,7 @@ static void noinstr exit_to_kernel_mode(struct pt_regs *regs)
 	}
 }
 
-void noinstr arm64_enter_nmi(struct pt_regs *regs)
+static void noinstr arm64_enter_nmi(struct pt_regs *regs)
 {
 	regs->lockdep_hardirqs = lockdep_hardirqs_enabled();
 
@@ -88,7 +88,7 @@ void noinstr arm64_enter_nmi(struct pt_regs *regs)
 	ftrace_nmi_enter();
 }
 
-void noinstr arm64_exit_nmi(struct pt_regs *regs)
+static void noinstr arm64_exit_nmi(struct pt_regs *regs)
 {
 	bool restore = regs->lockdep_hardirqs;