On Fri, Jun 04, 2021 at 06:42:16PM +0100, Mark Rutland wrote:

On Fri, Jun 04, 2021 at 05:57:55PM +0100, Will Deacon wrote:

quoted

On Tue, May 25, 2021 at 07:32:53PM +0100, Mark Rutland wrote:

quoted

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>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/entry-common.c | 27 +++++++++++++++++++++++++++
 arch/arm64/kernel/traps.c        | 25 -------------------------
 2 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 9c0ed05b98c4..25531a0b547e 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

@@ -159,6 +160,32 @@ 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"
+	};

If you're rejigging this array anyway, maybe initialising it as:

	[BAD_SYNC]	= "Synchronous Abort",
	[BAD_IRQ]	= ...

might make it even clearer. Up to you.

Since I'm removing the BAD_* definitions (and the array) in a latter
patch, I'd prefer to leave this as-is here so that this clearly has no
functional change.

Sure thing, I only spotted that after I'd already replied to this.

Will

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