ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE

The arm compiler internally interprets an inline assembly label
as an unsigned long value, not a pointer. As a result, under
CONFIG_FORTIFY_SOURCE, the address of a label has a size of 4 bytes,
which was tripping the runtime checks. Instead, we can just cast the label
(as done with the size calculations earlier).

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1639397

Reported-by: William Cohen <[email protected]>
Fixes: 6974f0c ("include/linux/string.h: add the option of fortified string.h functions")
Cc: [email protected]
Acked-by: Laura Abbott <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Tested-by: William Cohen <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Russell King <[email protected]>

Author: kees

arch/arm/probes/kprobes/opt-arm.c

@@ -247,7 +247,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *or
 	}
 
 	/* Copy arch-dep-instance from template. */
-	memcpy(code, &optprobe_template_entry,
+	memcpy(code, (unsigned char *)optprobe_template_entry,
 			TMPL_END_IDX * sizeof(kprobe_opcode_t));
 
 	/* Adjust buffer according to instruction. */