--- /dev/null
+From 71eac7063698b7d7b8fafb1683ac24a034541141 Mon Sep 17 00:00:00 2001
+From: Zhang Rui <rui.zhang@intel.com>
+Date: Fri, 14 Oct 2022 17:01:47 +0800
+Subject: x86/topology: Fix duplicated core ID within a package
+
+From: Zhang Rui <rui.zhang@intel.com>
+
+commit 71eac7063698b7d7b8fafb1683ac24a034541141 upstream.
+
+Today, core ID is assumed to be unique within each package.
+
+But an AlderLake-N platform adds a Module level between core and package,
+Linux excludes the unknown modules bits from the core ID, resulting in
+duplicate core ID's.
+
+To keep core ID unique within a package, Linux must include all APIC-ID
+bits for known or unknown levels above the core and below the package
+in the core ID.
+
+It is important to understand that core ID's have always come directly
+from the APIC-ID encoding, which comes from the BIOS. Thus there is no
+guarantee that they start at 0, or that they are contiguous.
+As such, naively using them for array indexes can be problematic.
+
+[ dhansen: un-known -> unknown ]
+
+Fixes: 7745f03eb395 ("x86/topology: Add CPUID.1F multi-die/package support")
+Suggested-by: Len Brown <len.brown@intel.com>
+Signed-off-by: Zhang Rui <rui.zhang@intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Reviewed-by: Len Brown <len.brown@intel.com>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/20221014090147.1836-5-rui.zhang@intel.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/topology.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/x86/kernel/cpu/topology.c
++++ b/arch/x86/kernel/cpu/topology.c
+@@ -141,7 +141,7 @@ int detect_extended_topology(struct cpui
+ sub_index++;
+ }
+
+- core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
++ core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width;
+ die_select_mask = (~(-1 << die_plus_mask_width)) >>
+ core_plus_mask_width;
+
--- /dev/null
+From 2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 Mon Sep 17 00:00:00 2001
+From: Zhang Rui <rui.zhang@intel.com>
+Date: Fri, 14 Oct 2022 17:01:46 +0800
+Subject: x86/topology: Fix multiple packages shown on a single-package system
+
+From: Zhang Rui <rui.zhang@intel.com>
+
+commit 2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 upstream.
+
+CPUID.1F/B does not enumerate Package level explicitly, instead, all the
+APIC-ID bits above the enumerated levels are assumed to be package ID
+bits.
+
+Current code gets package ID by shifting out all the APIC-ID bits that
+Linux supports, rather than shifting out all the APIC-ID bits that
+CPUID.1F enumerates. This introduces problems when CPUID.1F enumerates a
+level that Linux does not support.
+
+For example, on a single package AlderLake-N, there are 2 Ecore Modules
+with 4 atom cores in each module. Linux does not support the Module
+level and interprets the Module ID bits as package ID and erroneously
+reports a multi module system as a multi-package system.
+
+Fix this by using APIC-ID bits above all the CPUID.1F enumerated levels
+as package ID.
+
+[ dhansen: spelling fix ]
+
+Fixes: 7745f03eb395 ("x86/topology: Add CPUID.1F multi-die/package support")
+Suggested-by: Len Brown <len.brown@intel.com>
+Signed-off-by: Zhang Rui <rui.zhang@intel.com>
+Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
+Reviewed-by: Len Brown <len.brown@intel.com>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/20221014090147.1836-4-rui.zhang@intel.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/cpu/topology.c | 14 ++++++++++----
+ 1 file changed, 10 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/kernel/cpu/topology.c
++++ b/arch/x86/kernel/cpu/topology.c
+@@ -96,6 +96,7 @@ int detect_extended_topology(struct cpui
+ unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
+ unsigned int core_select_mask, core_level_siblings;
+ unsigned int die_select_mask, die_level_siblings;
++ unsigned int pkg_mask_width;
+ bool die_level_present = false;
+ int leaf;
+
+@@ -111,10 +112,10 @@ int detect_extended_topology(struct cpui
+ core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
+ core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+ die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
+- die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
++ pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+
+ sub_index = 1;
+- do {
++ while (true) {
+ cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
+
+ /*
+@@ -132,8 +133,13 @@ int detect_extended_topology(struct cpui
+ die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+ }
+
++ if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE)
++ pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
++ else
++ break;
++
+ sub_index++;
+- } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
++ }
+
+ core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
+ die_select_mask = (~(-1 << die_plus_mask_width)) >>
+@@ -148,7 +154,7 @@ int detect_extended_topology(struct cpui
+ }
+
+ c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
+- die_plus_mask_width);
++ pkg_mask_width);
+ /*
+ * Reinit the apicid, now that we have extended initial_apicid.
+ */
projects / thirdparty / kernel / stable-queue.git / commitdiff
