From: Bhavna Sarathy <bnagendr@redhat.com>
Date: Mon, 12 Apr 2010 19:17:00 -0400
Subject: [cpu] fix boot crash in 32-bit install on AMD cpus
Message-id: <20100412192131.8760.34926.sendpatchset@localhost.localdomain>
Patchwork-id: 24103
O-Subject: [RHEL5 PATCH V2] Fix boot crash in 32-bit RHEL
Bugzilla: 575799
RH-Acked-by: Jarod Wilson <jarod@redhat.com>

Resolves BZ 575799

This patch fixes a kernel panic seen on RHEL5.5 32-bit during boot up.

Note: The Kconfig is quite different in RHEL5 when compared to upstream and the
Kconfig changes are not necessary to fix this bug.

The patch has been applied to the RHEL5.5 RC kernel (which probably is the GA
kernel) and 32-bit has been tested successfully on AMD reference platforms.

This patch needs to be applied to both RHEL5.6 and RHEL5.5.z

Upstream link:
http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=0e152cd7c16832bd5cadee0c2e41d9959bc9b6f9

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/arch/i386/kernel/cpu/intel_cacheinfo.c b/arch/i386/kernel/cpu/intel_cacheinfo.c
index 81c2c40..2f3328a 100644
--- a/arch/i386/kernel/cpu/intel_cacheinfo.c
+++ b/arch/i386/kernel/cpu/intel_cacheinfo.c
@@ -331,6 +331,10 @@ amd_check_l3_disable(int index, struct _cpuid4_info *this_leaf)
 	     (boot_cpu_data.x86_mask  < 0x1)))
 		return;
 
+	/* not in virtualized environments */
+	if (num_k8_northbridges == 0)
+		return;
+
 	this_leaf->can_disable = true;
 	this_leaf->l3_indices  = amd_calc_l3_indices();
 }
diff --git a/arch/x86_64/kernel/k8.c b/arch/x86_64/kernel/k8.c
index f9d9770..fedf7c8 100644
--- a/arch/x86_64/kernel/k8.c
+++ b/arch/x86_64/kernel/k8.c
@@ -116,3 +116,19 @@ void k8_flush_garts(void)
 }
 EXPORT_SYMBOL_GPL(k8_flush_garts);
 
+static __init int init_k8_nbs(void)
+{
+	int err = 0;
+
+	err = cache_k8_northbridges();
+
+	if (err < 0)
+		printk(KERN_NOTICE "K8 NB: Cannot enumerate AMD northbridges.\n");
+
+	return err;
+}
+
+/* This has to go after the PCI subsystem */
+fs_initcall(init_k8_nbs);
+
+