The following commit has been merged into the x86/misc branch of tip:
Commit-ID: bc7b2e629e0c9251ba96d864a30d34d1497b1b1b
Gitweb: https://git.kernel.org/tip/bc7b2e629e0c9251ba96d864a30d34d1497b1b1b
Author: Yazen Ghannam <yazen.ghannam@xxxxxxx>
AuthorDate: Tue, 07 Jan 2025 22:28:41
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Wed, 08 Jan 2025 10:49:20 +01:00
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: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20250107222847.3300430-7-yazen.ghannam@xxxxxxx
---
arch/x86/include/asm/amd_node.h | 5 +++++
arch/x86/kernel/amd_nb.c | 22 +++++++++++++---------
2 files changed, 18 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/amd_node.h b/arch/x86/include/asm/amd_node.h
index 3f097dd..419a0ad 100644
--- a/arch/x86/include/asm/amd_node.h
+++ b/arch/x86/include/asm/amd_node.h
@@ -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_*/
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 6218a04..6371fe9 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -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);
}
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