arm64/kernel: Move 'nokaslr' parsing out of early idreg code

Parsing and ignoring 'nokaslr' can be done from anywhere, except from
the code that runs very early and is therefore built with limitations on
the kind of relocations it is permitted to use.

So move it to a source file that is part of the ordinary kernel build.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20231129111555.3594833-63-ardb@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: ardbiesheuvel

arch/arm64/kernel/idreg-override.c

@@ -199,13 +199,6 @@ static const struct {
 	{ "nokaslr",			"arm64_sw.nokaslr=1" },
 };
 
-static int __init parse_nokaslr(char *unused)
-{
-	/* nokaslr param handling is done by early cpufeature code */
-	return 0;
-}
-early_param("nokaslr", parse_nokaslr);
-
 static int __init parse_hexdigit(const char *p, u64 *v)
 {
 	// skip "0x" if it comes next

arch/arm64/kernel/kaslr.c

@@ -36,3 +36,10 @@ void __init kaslr_init(void)
 	pr_info("KASLR enabled\n");
 	__kaslr_is_enabled = true;
 }
+
+static int __init parse_nokaslr(char *unused)
+{
+	/* nokaslr param handling is done by early cpufeature code */
+	return 0;
+}
+early_param("nokaslr", parse_nokaslr);