[PATCH V32 14/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down

Matthew Garrett matthewgarrett at google.com
Thu Apr 4 00:32:36 UTC 2019

From: Josh Boyer <jwboyer at redhat.com>

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 at redhat.com>
Signed-off-by: David Howells <dhowells at redhat.com>
Signed-off-by: Matthew Garrett <mjg59 at google.com>
cc: Dave Young <dyoung at redhat.com>
cc: linux-acpi at vger.kernel.org
 drivers/acpi/osl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index f29e427d0d1d..cd5bba7b8eb3 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -194,7 +194,8 @@ acpi_physical_address __init acpi_os_get_root_pointer(void)
 	acpi_physical_address pa;
-	if (acpi_rsdp)
+	if (acpi_rsdp && !kernel_is_locked_down("ACPI RSDP specification",
 		return acpi_rsdp;
 	pa = acpi_arch_get_root_pointer();

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