From 08b259631b5a1d912af4832847b5642f377d9101 Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Sun, 5 Feb 2017 11:50:22 +0100 Subject: x86/CPU/AMD: Fix Zen SMT topology After: a33d331761bc ("x86/CPU/AMD: Fix Bulldozer topology") our SMT scheduling topology for Fam17h systems is broken, because the ThreadId is included in the ApicId when SMT is enabled. So, without further decoding cpu_core_id is unique for each thread rather than the same for threads on the same core. This didn't affect systems with SMT disabled. Make cpu_core_id be what it is defined to be. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: # 4.9 Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170205105022.8705-2-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/amd.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 20dc44d1e6be..2b4cf04239b6 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -319,6 +319,13 @@ static void amd_get_topology(struct cpuinfo_x86 *c) if (c->x86 == 0x15) c->cu_id = ebx & 0xff; + if (c->x86 >= 0x17) { + c->cpu_core_id = ebx & 0xff; + + if (smp_num_siblings > 1) + c->x86_max_cores /= smp_num_siblings; + } + /* * We may have multiple LLCs if L3 caches exist, so check if we * have an L3 cache by looking at the L3 cache CPUID leaf. -- cgit