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Subject[tip:x86/cpu] x86/CPU/hygon: Fix phys_proc_id calculation logic for multi-die processors
Commit-ID:  e0ceeae708cebf22c990c3d703a4ca187dc837f5
Gitweb: https://git.kernel.org/tip/e0ceeae708cebf22c990c3d703a4ca187dc837f5
Author: Pu Wen <puwen@hygon.cn>
AuthorDate: Sat, 23 Mar 2019 23:42:20 +0800
Committer: Borislav Petkov <bp@suse.de>
CommitDate: Sat, 23 Mar 2019 17:41:09 +0100

x86/CPU/hygon: Fix phys_proc_id calculation logic for multi-die processors

The Hygon family 18h multi-die processor platform supports 1, 2 or
4-Dies per socket. The topology looks like this:

System View (with 1-Die 2-Socket):
|------------|
------ -----
SOCKET0 | D0 | | D1 | SOCKET1
------ -----

System View (with 2-Die 2-socket):
--------------------
| -------------|------
| | | |
------------ ------------
SOCKET0 | D1 -- D0 | | D3 -- D2 | SOCKET1
------------ ------------

System View (with 4-Die 2-Socket) :
--------------------
| -------------|------
| | | |
------------ ------------
| D1 -- D0 | | D7 -- D6 |
| | \/ | | | | \/ | |
SOCKET0 | | /\ | | | | /\ | | SOCKET1
| D2 -- D3 | | D4 -- D5 |
------------ ------------
| | | |
------|------------| |
--------------------

Currently

phys_proc_id = initial_apicid >> bits

calculates the physical processor ID from the initial_apicid by shifting
*bits*.

However, this does not work for 1-Die and 2-Die 2-socket systems.

According to document [1] section 2.1.11.1, the bits is the value of
CPUID_Fn80000008_ECX[12:15]. The possible values are 4, 5 or 6 which
mean:

4 - 1 die
5 - 2 dies
6 - 3/4 dies.

Hygon programs the initial ApicId the same way as AMD. The ApicId is
read from CPUID_Fn00000001_EBX (see section 2.1.11.1 of referrence [1])
and the definition is as below (see section 2.1.10.2.1.3 of [1]):

-------------------------------------------------
Bit | 6 | 5 4 | 3 | 2 1 0 |
|-----------|---------|--------|----------------|
IDs | Socket ID | Node ID | CCX ID | Core/Thread ID |
-------------------------------------------------

So for 3/4-Die configurations, the bits variable is 6, which is the same
as the ApicID definition field.

For 1-Die and 2-Die configurations, bits is 4 or 5, which will cause the
right shifted result to not be exactly the value of socket ID.

However, the socket ID should be obtained from ApicId[6]. To fix the
problem and match the ApicID field definition, set the shift bits to 6
for all Hygon family 18h multi-die CPUs.

Because AMD doesn't have 2-Socket systems with 1-Die/2-Die processors
(see reference [2]), this doesn't need to be changed on the AMD side but
only for Hygon.

References:
[1] https://www.amd.com/system/files/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf
[2] https://www.amd.com/en/products/specifications/processors

[bp: heavily massage commit message. ]

Signed-off-by: Pu Wen <puwen@hygon.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1553355740-19999-1-git-send-email-puwen@hygon.cn
---
arch/x86/kernel/cpu/hygon.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/cpu/hygon.c b/arch/x86/kernel/cpu/hygon.c
index cf25405444ab..415621ddb8a2 100644
--- a/arch/x86/kernel/cpu/hygon.c
+++ b/arch/x86/kernel/cpu/hygon.c
@@ -19,6 +19,8 @@

#include "cpu.h"

+#define APICID_SOCKET_ID_BIT 6
+
/*
* nodes_per_socket: Stores the number of nodes per socket.
* Refer to CPUID Fn8000_001E_ECX Node Identifiers[10:8]
@@ -87,6 +89,9 @@ static void hygon_get_topology(struct cpuinfo_x86 *c)
if (!err)
c->x86_coreid_bits = get_count_order(c->x86_max_cores);

+ /* Socket ID is ApicId[6] for these processors. */
+ c->phys_proc_id = c->apicid >> APICID_SOCKET_ID_BIT;
+
cacheinfo_hygon_init_llc_id(c, cpu, node_id);
} else if (cpu_has(c, X86_FEATURE_NODEID_MSR)) {
u64 value;
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