ACPICA: Detect FACS even for hardware reduced platforms

ACPICA commit 44fc328a1a14b097d92b8be83989e4bf69b6e6cb

The FACS is optional even on hardware reduced platforms, and may exist
for the purpose of communicating the hardware_signature field to provoke
a clean reboot instead of a resume from hibernation.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240412073530.2222496-2-dwmw2@infradead.org
Signed-off-by: Will Deacon <will@kernel.org>

Author: dwmw2

drivers/acpi/acpica/tbfadt.c

@@ -315,23 +315,19 @@ void acpi_tb_parse_fadt(void)
 				       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
 				       NULL, FALSE, TRUE, &acpi_gbl_dsdt_index);
 
-	/* If Hardware Reduced flag is set, there is no FACS */
-
-	if (!acpi_gbl_reduced_hardware) {
-		if (acpi_gbl_FADT.facs) {
-			acpi_tb_install_standard_table((acpi_physical_address)
-						       acpi_gbl_FADT.facs,
-						       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
-						       NULL, FALSE, TRUE,
-						       &acpi_gbl_facs_index);
-		}
-		if (acpi_gbl_FADT.Xfacs) {
-			acpi_tb_install_standard_table((acpi_physical_address)
-						       acpi_gbl_FADT.Xfacs,
-						       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
-						       NULL, FALSE, TRUE,
-						       &acpi_gbl_xfacs_index);
-		}
+	if (acpi_gbl_FADT.facs) {
+		acpi_tb_install_standard_table((acpi_physical_address)
+					       acpi_gbl_FADT.facs,
+					       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
+					       NULL, FALSE, TRUE,
+					       &acpi_gbl_facs_index);
+	}
+	if (acpi_gbl_FADT.Xfacs) {
+		acpi_tb_install_standard_table((acpi_physical_address)
+					       acpi_gbl_FADT.Xfacs,
+					       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
+					       NULL, FALSE, TRUE,
+					       &acpi_gbl_xfacs_index);
 	}
 }
 

drivers/acpi/acpica/tbutils.c

@@ -36,12 +36,7 @@ acpi_status acpi_tb_initialize_facs(void)
 {
 	struct acpi_table_facs *facs;
 
-	/* If Hardware Reduced flag is set, there is no FACS */
-
-	if (acpi_gbl_reduced_hardware) {
-		acpi_gbl_FACS = NULL;
-		return (AE_OK);
-	} else if (acpi_gbl_FADT.Xfacs &&
+	if (acpi_gbl_FADT.Xfacs &&
 		   (!acpi_gbl_FADT.facs
 		    || !acpi_gbl_use32_bit_facs_addresses)) {
 		(void)acpi_get_table_by_index(acpi_gbl_xfacs_index,