scripts/kallsyms: filter arm64's __efistub_ symbols

commit 1212f7a16a upstream.

On arm64, the EFI stub and the kernel proper are essentially the same
binary, although the EFI stub executes at a different virtual address
as the kernel. For this reason, the EFI stub is restricted in the
symbols it can link to, which is ensured by prefixing all EFI stub
symbols with __efistub_ (and emitting __efistub_ prefixed aliases for
routines that may be shared between the core kernel and the stub)

These symbols are leaking into kallsyms, polluting the namespace, so
let's filter them explicitly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/kallsyms.c

@@ -221,6 +221,7 @@ static int symbol_valid(struct sym_entry *s)
 
 	static char *special_prefixes[] = {
 		"__crc_",		/* modversions */
+		"__efistub_",		/* arm64 EFI stub namespace */
 		NULL };
 
 	static char *special_suffixes[] = {