x86/cpu: Provide an AMD/HYGON specific topology parser

AMD/HYGON uses various methods for topology evaluation:

  - Leaf 0x80000008 and 0x8000001e based with an optional leaf 0xb,
    which is the preferred variant for modern CPUs.

    Leaf 0xb will be superseded by leaf 0x80000026 soon, which is just
    another variant of the Intel 0x1f leaf for whatever reasons.
    
  - Subleaf 0x80000008 and NODEID_MSR base

  - Legacy fallback

That code is following the principle of random bits and pieces all over the
place which results in multiple evaluations and impenetrable code flows in
the same way as the Intel parsing did.

Provide a sane implementation by clearly separating the three variants and
bringing them in the proper preference order in one place.

This provides the parsing for both AMD and HYGON because there is no point
in having a separate HYGON parser which only differs by 3 lines of
code. Any further divergence between AMD and HYGON can be handled in
different functions, while still sharing the existing parsers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Wang Wendy <wendy.wang@intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20240212153625.020038641@linutronix.de

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index ef99499c9bbe..e1d1a7b7c8a9 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -11,11 +11,13 @@
 
 struct x86_topology_system x86_topo_system __ro_after_init;
 
+unsigned int __amd_nodes_per_pkg __ro_after_init;
+EXPORT_SYMBOL_GPL(__amd_nodes_per_pkg);
+
 void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
 		      unsigned int shift, unsigned int ncpus)
 {
-	tscan->dom_shifts[dom] = shift;
-	tscan->dom_ncpus[dom] = ncpus;
+	topology_update_dom(tscan, dom, shift, ncpus);
 
 	/* Propagate to the upper levels */
 	for (dom++; dom < TOPO_MAX_DOMAIN; dom++) {
@@ -153,6 +155,13 @@ static void topo_set_ids(struct topo_scan *tscan)
 	/* Package relative core ID */
 	c->topo.core_id = (apicid & topo_domain_mask(TOPO_PKG_DOMAIN)) >>
 		x86_topo_system.dom_shifts[TOPO_SMT_DOMAIN];
+
+	/* Temporary workaround */
+	if (tscan->amd_nodes_per_pkg)
+		c->topo.amd_node_id = c->topo.die_id = tscan->amd_node_id;
+
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		cpu_topology_fixup_amd(tscan);
 }
 
 static void topo_set_max_cores(struct topo_scan *tscan)
@@ -237,4 +246,10 @@ void __init cpu_init_topology(struct cpuinfo_x86 *c)
 	 */
 	__max_die_per_package = tscan.dom_ncpus[TOPO_DIE_DOMAIN] /
 		tscan.dom_ncpus[TOPO_DIE_DOMAIN - 1];
+	/*
+	 * AMD systems have Nodes per package which cannot be mapped to
+	 * APIC ID.
+	 */
+	if (c->x86_vendor == X86_VENDOR_AMD || c->x86_vendor == X86_VENDOR_HYGON)
+		__amd_nodes_per_pkg = __max_die_per_package = tscan.amd_nodes_per_pkg;
 }