linux/arch/x86_64/pci/k8-bus.c
Andi Kleen d3813fcf10 [PATCH] x86_64: Don't oops at boot when empty Opteron node has IO
The code to detect IO links on Opteron would not check
if the node had actually memory. This could lead to pci_bus_to_node
returning an invalid node, which might cause crashes later
when dma_alloc_coherent passes it to page_alloc_node().

The bug has been there forever but for some reason
it is causing now crashes.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-23 19:59:39 -07:00

74 lines
2.0 KiB
C

#include <linux/init.h>
#include <linux/pci.h>
#include <asm/mpspec.h>
#include <linux/cpumask.h>
/*
* This discovers the pcibus <-> node mapping on AMD K8.
*
* RED-PEN need to call this again on PCI hotplug
* RED-PEN empty cpus get reported wrong
*/
#define NODE_ID_REGISTER 0x60
#define NODE_ID(dword) (dword & 0x07)
#define LDT_BUS_NUMBER_REGISTER_0 0x94
#define LDT_BUS_NUMBER_REGISTER_1 0xB4
#define LDT_BUS_NUMBER_REGISTER_2 0xD4
#define NR_LDT_BUS_NUMBER_REGISTERS 3
#define SECONDARY_LDT_BUS_NUMBER(dword) ((dword >> 8) & 0xFF)
#define SUBORDINATE_LDT_BUS_NUMBER(dword) ((dword >> 16) & 0xFF)
#define PCI_DEVICE_ID_K8HTCONFIG 0x1100
/**
* fill_mp_bus_to_cpumask()
* fills the mp_bus_to_cpumask array based according to the LDT Bus Number
* Registers found in the K8 northbridge
*/
__init static int
fill_mp_bus_to_cpumask(void)
{
struct pci_dev *nb_dev = NULL;
int i, j;
u32 ldtbus, nid;
static int lbnr[3] = {
LDT_BUS_NUMBER_REGISTER_0,
LDT_BUS_NUMBER_REGISTER_1,
LDT_BUS_NUMBER_REGISTER_2
};
while ((nb_dev = pci_get_device(PCI_VENDOR_ID_AMD,
PCI_DEVICE_ID_K8HTCONFIG, nb_dev))) {
pci_read_config_dword(nb_dev, NODE_ID_REGISTER, &nid);
for (i = 0; i < NR_LDT_BUS_NUMBER_REGISTERS; i++) {
pci_read_config_dword(nb_dev, lbnr[i], &ldtbus);
/*
* if there are no busses hanging off of the current
* ldt link then both the secondary and subordinate
* bus number fields are set to 0.
*
* RED-PEN
* This is slightly broken because it assumes
* HT node IDs == Linux node ids, which is not always
* true. However it is probably mostly true.
*/
if (!(SECONDARY_LDT_BUS_NUMBER(ldtbus) == 0
&& SUBORDINATE_LDT_BUS_NUMBER(ldtbus) == 0)) {
for (j = SECONDARY_LDT_BUS_NUMBER(ldtbus);
j <= SUBORDINATE_LDT_BUS_NUMBER(ldtbus);
j++) {
int node = NODE_ID(nid);
if (!node_online(node))
node = 0;
pci_bus_to_node[j] = node;
}
}
}
}
return 0;
}
fs_initcall(fill_mp_bus_to_cpumask);