Revert "x86/ioapic: Add register level checks to detect bogus io-apic entries"

This reverts commit 273fb194
[73d63d03 upstream]

It causes problems, so needs to be reverted from 3.2-stable for now.
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jon Dufresne <jon@jondufresne.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <yinghai@kernel.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Teck Choon Giam <giamteckchoon@gmail.com>
Cc: Ben Guthro <ben@guthro.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/kernel/apic/io_apic.c

@@ -3963,36 +3963,18 @@ int mp_find_ioapic_pin(int ioapic, u32 gsi)
 static __init int bad_ioapic(unsigned long address)
 {
 	if (nr_ioapics >= MAX_IO_APICS) {
-		pr_warn("WARNING: Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
-			MAX_IO_APICS, nr_ioapics);
+		printk(KERN_WARNING "WARNING: Max # of I/O APICs (%d) exceeded "
+		       "(found %d), skipping\n", MAX_IO_APICS, nr_ioapics);
 		return 1;
 	}
 	if (!address) {
-		pr_warn("WARNING: Bogus (zero) I/O APIC address found in table, skipping!\n");
+		printk(KERN_WARNING "WARNING: Bogus (zero) I/O APIC address"
+		       " found in table, skipping!\n");
 		return 1;
 	}
 	return 0;
 }
 
-static __init int bad_ioapic_register(int idx)
-{
-	union IO_APIC_reg_00 reg_00;
-	union IO_APIC_reg_01 reg_01;
-	union IO_APIC_reg_02 reg_02;
-
-	reg_00.raw = io_apic_read(idx, 0);
-	reg_01.raw = io_apic_read(idx, 1);
-	reg_02.raw = io_apic_read(idx, 2);
-
-	if (reg_00.raw == -1 && reg_01.raw == -1 && reg_02.raw == -1) {
-		pr_warn("I/O APIC 0x%x registers return all ones, skipping!\n",
-			mpc_ioapic_addr(idx));
-		return 1;
-	}
-
-	return 0;
-}
-
 void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
 {
 	int idx = 0;
@@ -4009,12 +3991,6 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
 	ioapics[idx].mp_config.apicaddr = address;
 
 	set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
-
-	if (bad_ioapic_register(idx)) {
-		clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
-		return;
-	}
-
 	ioapics[idx].mp_config.apicid = io_apic_unique_id(id);
 	ioapics[idx].mp_config.apicver = io_apic_get_version(idx);
 
@@ -4035,10 +4011,10 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
 	if (gsi_cfg->gsi_end >= gsi_top)
 		gsi_top = gsi_cfg->gsi_end + 1;
 
-	pr_info("IOAPIC[%d]: apic_id %d, version %d, address 0x%x, GSI %d-%d\n",
-		idx, mpc_ioapic_id(idx),
-		mpc_ioapic_ver(idx), mpc_ioapic_addr(idx),
-		gsi_cfg->gsi_base, gsi_cfg->gsi_end);
+	printk(KERN_INFO "IOAPIC[%d]: apic_id %d, version %d, address 0x%x, "
+	       "GSI %d-%d\n", idx, mpc_ioapic_id(idx),
+	       mpc_ioapic_ver(idx), mpc_ioapic_addr(idx),
+	       gsi_cfg->gsi_base, gsi_cfg->gsi_end);
 
 	nr_ioapics++;
 }