ACPI: Fix boot problem related to APEI with acpi_disabled set

Commit 415e12b23792 ("PCI/ACPI: Request _OSC control once for each root
bridge (v3)") put the acpi_hest_init() call in acpi_pci_root_init() into
a wrong place, presumably because the author confused acpi_pci_disabled
with acpi_disabled.  Bring the code ordering in acpi_pci_root_init()
back to sanity.

Additionally, make sure that hest_disable is set when acpi_disabled is
set, which is going to prevent acpi_hest_parse(), that still may be
executed for acpi_disabled=1 through aer_acpi_firmware_first(), from
crashing because of uninitialized hest_tab.

Reported-and-tested-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/acpi/apei/hest.c

@@ -201,14 +201,14 @@ void __init acpi_hest_init(void)
 	int rc = -ENODEV;
 	unsigned int ghes_count = 0;
 
-	if (acpi_disabled)
-		return;
-
 	if (hest_disable) {
 		pr_info(HEST_PFX "Table parsing disabled.\n");
 		return;
 	}
 
+	if (acpi_disabled)
+		goto err;
+
 	status = acpi_get_table(ACPI_SIG_HEST, 0,
 				(struct acpi_table_header **)&hest_tab);
 	if (status == AE_NOT_FOUND) {

drivers/acpi/pci_root.c

@@ -633,11 +633,11 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type)
 
 static int __init acpi_pci_root_init(void)
 {
+	acpi_hest_init();
+
 	if (acpi_pci_disabled)
 		return 0;
 
-	acpi_hest_init();
-
 	pci_acpi_crs_quirks();
 	if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
 		return -ENODEV;