x86, k8 nb: Fix boot crash: enable k8_northbridges unconditionally on AMD systems

de957628ce7c84764ff41331111036b3ae5bad0f changed setting of the
x86_init.iommu.iommu_init function ptr only when GART IOMMU is
found.

One side effect of it is that num_k8_northbridges
is not initialized anymore if not explicitly
called. This resulted in uninitialized pointers in
<arch/x86/kernel/cpu/intel_cacheinfo.c:amd_calc_l3_indices()>,
for example, which uses the num_k8_northbridges thing through
node_to_k8_nb_misc().

Fix that through an initcall that runs right after the PCI
subsystem and does all the scanning. Then, remove initialization
in gart_iommu_init() which is a rootfs_initcall and we're
running before that.

What is more, since num_k8_northbridges is being used in other
places beside GART IOMMU, include it whenever we add AMD CPU
support. The previous dependency chain in kconfig contained

K8_NB depends on AGP_AMD64|GART_IOMMU

which was clearly incorrect. The more natural way in terms of
hardware dependency should be

AGP_AMD64|GART_IOMMU depends on K8_NB depends on CPU_SUP_AMD &&
PCI. Make it so Number One!

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20100312144303.GA29262@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index eb4092568f9e..ddb52b8d38a7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -627,7 +627,7 @@ config GART_IOMMU
         bool "GART IOMMU support" if EMBEDDED
         default y
         select SWIOTLB
-        depends on X86_64 && PCI
+        depends on X86_64 && PCI && K8_NB
         ---help---
           Support for full DMA access of devices with 32bit memory access only
           on systems with more than 3GB. This is usually needed for USB,
@@ -2026,7 +2026,7 @@ endif # X86_32
 
 config K8_NB
         def_bool y
-        depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
+        depends on CPU_SUP_AMD && PCI
 
 source "drivers/pcmcia/Kconfig"