From: Josh Boyer <jwboyer@redhat.com>
Date: Wed, 8 Nov 2017 15:11:34 +0000
Subject: [16/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been
 locked down
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=67890a0361626ec3e035264656896c77670c414b

This option allows userspace to pass the RSDP address to the kernel, which
makes it possible for a user to modify the workings of hardware .  Reject
the option when the kernel is locked down.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
cc: Dave Young <dyoung@redhat.com>
cc: linux-acpi@vger.kernel.org
---
 drivers/acpi/osl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/drivers/acpi/osl.c
===================================================================
--- linux.orig/drivers/acpi/osl.c
+++ linux/drivers/acpi/osl.c
@@ -194,7 +194,7 @@ acpi_physical_address __init acpi_os_get
 	acpi_physical_address pa;
 
 #ifdef CONFIG_KEXEC
-	if (acpi_rsdp)
+	if (acpi_rsdp && !kernel_is_locked_down("ACPI RSDP specification"))
 		return acpi_rsdp;
 #endif
 	pa = acpi_arch_get_root_pointer();
