Commit-ID: a33d331761bc5dd330499ca5ceceb67f0640a8e6
Gitweb: http://git.kernel.org/tip/a33d331761bc5dd330499ca5ceceb67f0640a8e6
Author: Borislav Petkov <[email protected]>
AuthorDate: Thu, 5 Jan 2017 10:26:38 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 6 Jan 2017 08:37:41 +0100
x86/CPU/AMD: Fix Bulldozer topology
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 <[email protected]>
Tested-by: Yazen Ghannam <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: <[email protected]> # v4.6+
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 8196dab4fc15 ("x86/cpu: Get rid of compute_unit_id")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/cpu/amd.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 71cae73..1d31672 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -309,15 +309,8 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
/* 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
