arm64: entry: Use irqentry_{enter_from,exit_to}_kernel_mode()

The generic irqentry code now provides irqentry_enter_from_kernel_mode()
and irqentry_exit_to_kernel_mode(), which can be used when an exception
is known to be taken from kernel mode. These can be inlined into
architecture-specific entry code, and avoid redundant work to test
whether the exception was taken from user mode.

Use these in arm64_enter_from_kernel_mode() and
arm64_exit_to_kernel_mode(), which are only used for exceptions known to
be taken from kernel mode. This will remove a small amount of redundant
work, and will permit further changes to arm64_exit_to_kernel_mode() in
subsequent patches.

There should be no funcitonal change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: mrutland-arm

arch/arm64/kernel/entry-common.c

@@ -39,7 +39,7 @@ static noinstr irqentry_state_t arm64_enter_from_kernel_mode(struct pt_regs *reg
 {
 	irqentry_state_t state;
 
-	state = irqentry_enter(regs);
+	state = irqentry_enter_from_kernel_mode(regs);
 	mte_check_tfsr_entry();
 	mte_disable_tco_entry(current);
 
@@ -55,7 +55,7 @@ static void noinstr arm64_exit_to_kernel_mode(struct pt_regs *regs,
 					      irqentry_state_t state)
 {
 	mte_check_tfsr_exit();
-	irqentry_exit(regs, state);
+	irqentry_exit_to_kernel_mode(regs, state);
 }
 
 /*