Commit bc7b2e62 authored by Yazen Ghannam's avatar Yazen Ghannam Committed by Borislav Petkov (AMD)
Browse files

x86/amd_nb: Use topology info to get AMD node count 



Currently, the total AMD node count is determined by searching and counting
CPU/node devices using PCI IDs.

However, AMD node information is already available through topology
CPUID/MSRs. The recent topology rework has made this info easier to access.

Replace the node counting code with a simple product of topology info.

Every node/northbridge is expected to have a 'misc' device. Clear everything
out if a 'misc' device isn't found on a node.

Signed-off-by: default avatarYazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250107222847.3300430-7-yazen.ghannam@amd.com
parent 40a5f6ff

arch/x86/include/asm/amd_node.h

+5 −0
Original line number Diff line number Diff line
@@ -25,4 +25,9 @@ 
struct pci_dev *amd_node_get_func(u16 node, u8 func);

struct pci_dev *amd_node_get_root(u16 node);



static inline u16 amd_num_nodes(void)

{

	return topology_amd_nodes_per_pkg() * topology_max_packages();

}



#endif /*_ASM_X86_AMD_NODE_H_*/

arch/x86/kernel/amd_nb.c

+13 −9
Original line number Diff line number Diff line
@@ -186,7 +186,6 @@ static int amd_cache_northbridges(void) 
	const struct pci_device_id *misc_ids = amd_nb_misc_ids;

	struct pci_dev *misc;

	struct amd_northbridge *nb;

	u16 misc_count = 0;

	u16 i;



	if (amd_northbridges.num)
@@ -196,25 +195,30 @@ static int amd_cache_northbridges(void) 
		misc_ids = hygon_nb_misc_ids;

	}



	misc = NULL;

	while ((misc = next_northbridge(misc, misc_ids)))

		misc_count++;



	if (!misc_count)

		return -ENODEV;

	amd_northbridges.num = amd_num_nodes();



	nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);

	nb = kcalloc(amd_northbridges.num, sizeof(struct amd_northbridge), GFP_KERNEL);

	if (!nb)

		return -ENOMEM;



	amd_northbridges.nb = nb;

	amd_northbridges.num = misc_count;



	misc = NULL;

	for (i = 0; i < amd_northbridges.num; i++) {

		node_to_amd_nb(i)->root = amd_node_get_root(i);

		node_to_amd_nb(i)->misc = misc =

			next_northbridge(misc, misc_ids);



		/*

		 * Each Northbridge must have a 'misc' device.

		 * If not, then uninitialize everything.

		 */

		if (!node_to_amd_nb(i)->misc) {

			amd_northbridges.num = 0;

			kfree(nb);

			return -ENODEV;

		}



		node_to_amd_nb(i)->link = amd_node_get_func(i, 4);

	}