arm64: entry: move bad_mode() to entry-common.c

In subsequent patches we'll rework the way bad_mode() is called by
exception entry code. In preparation for this, let's move bad_mode()
itself into entry-common.c.

Let's also mark it as noinstr (e.g. to prevent it being kprobed), and
let's also make the `handler` array a local variable, as this is only
use by bad_mode(), and will be removed entirely in a subsequent patch.

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

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/20210607094624.34689-12-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index ae1b6d7c00e1..74d09fd3dafa 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -22,6 +22,7 @@
 #include <asm/processor.h>
 #include <asm/stacktrace.h>
 #include <asm/sysreg.h>
+#include <asm/system_misc.h>
 
 /*
  * This is intended to match the logic in irqentry_enter(), handling the kernel
@@ -156,6 +157,32 @@ static void do_interrupt_handler(struct pt_regs *regs,
 extern void (*handle_arch_irq)(struct pt_regs *);
 extern void (*handle_arch_fiq)(struct pt_regs *);
 
+/*
+ * bad_mode handles the impossible case in the exception vector. This is always
+ * fatal.
+ */
+asmlinkage void noinstr bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
+{
+	const char *handler[] = {
+		"Synchronous Abort",
+		"IRQ",
+		"FIQ",
+		"Error"
+	};
+
+	arm64_enter_nmi(regs);
+
+	console_verbose();
+
+	pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
+		handler[reason], smp_processor_id(), esr,
+		esr_get_class_string(esr));
+
+	__show_regs(regs);
+	panic("bad mode");
+}
+
+
 #ifdef CONFIG_ARM64_ERRATUM_1463225
 static DEFINE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);