4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <b...@suse.de>
commit a33d331761bc5dd330499ca5ceceb67f0640a8e6 upstream.
The following commit:
8196dab4fc15 ("x86/cpu: Get rid of compute_unit_id")
... broke the initial strategy for Bulldozer-based cores' topology,
where we consider each thread of a compute unit a standalone core
and not a HT or SMT thread.
Revert to the firmware-supplied core_id numbering and do not make
them thread siblings as we don't consider them for such even if they
technically are, more or less.
Reported-and-tested-by: Brice Goglin <brice.gog...@inria.fr>
Tested-by: Yazen Ghannam <yazen.ghan...@amd.com>
Signed-off-by: Borislav Petkov <b...@suse.de>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Fixes: 8196dab4fc15 ("x86/cpu: Get rid of compute_unit_id")
Link: http://lkml.kernel.org/r/20170105092638.5247-1...@alien8.de
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/kernel/cpu/amd.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -309,15 +309,8 @@ static void amd_get_topology(struct cpui
/* get information required for multi-node processors */
if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
- u32 eax, ebx, ecx, edx;
- cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
- node_id = ecx & 7;
-
- /* get compute unit information */
- smp_num_siblings = ((ebx >> 8) & 3) + 1;
- c->x86_max_cores /= smp_num_siblings;
- c->cpu_core_id = ebx & 0xff;
+ node_id = cpuid_ecx(0x8000001e) & 7;
/*
* We may have multiple LLCs if L3 caches exist, so check if we
