x86/PCI: Abort if legacy init fails

If the legacy PCI init fails, then there are no PCI config space accesors
available, but the code continues and tries to scan the busses, which fails
due to the lack of config space accessors.

Return right away, if the last init fallback fails.

Switch the few printks to pr_info while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <helgaas@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/20170316215057.047576516@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/pci/legacy.c

@@ -24,12 +24,10 @@ static void pcibios_fixup_peer_bridges(void)
 
 int __init pci_legacy_init(void)
 {
-	if (!raw_pci_ops) {
-		printk("PCI: System does not support PCI\n");
-		return 0;
-	}
+	if (!raw_pci_ops)
+		return 1;
 
-	printk("PCI: Probing PCI hardware\n");
+	pr_info("PCI: Probing PCI hardware\n");
 	pcibios_scan_root(0);
 	return 0;
 }
@@ -46,7 +44,7 @@ void pcibios_scan_specific_bus(int busn)
 		if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) &&
 		    l != 0x0000 && l != 0xffff) {
 			DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);
-			printk(KERN_INFO "PCI: Discovered peer bus %02x\n", busn);
+			pr_info("PCI: Discovered peer bus %02x\n", busn);
 			pcibios_scan_root(busn);
 			return;
 		}
@@ -60,8 +58,12 @@ static int __init pci_subsys_init(void)
 	 * The init function returns an non zero value when
 	 * pci_legacy_init should be invoked.
 	 */
-	if (x86_init.pci.init())
-		pci_legacy_init();
+	if (x86_init.pci.init()) {
+		if (pci_legacy_init()) {
+			pr_info("PCI: System does not support PCI\n");
+			return -ENODEV;
+		}
+	}
 
 	pcibios_fixup_peer_bridges();
 	x86_init.pci.init_irq();