From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/arch/x86/kernel/acpi/cstate.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 43 insertions(+), 0 deletions(-)
diff --git a/kernel/arch/x86/kernel/acpi/cstate.c b/kernel/arch/x86/kernel/acpi/cstate.c
index 92539a1..d28d43d 100644
--- a/kernel/arch/x86/kernel/acpi/cstate.c
+++ b/kernel/arch/x86/kernel/acpi/cstate.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2005 Intel Corporation
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
@@ -51,6 +52,48 @@
if (c->x86_vendor == X86_VENDOR_INTEL &&
(c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
flags->bm_control = 0;
+ /*
+ * For all recent Centaur CPUs, the ucode will make sure that each
+ * core can keep cache coherence with each other while entering C3
+ * type state. So, set bm_check to 1 to indicate that the kernel
+ * doesn't need to execute a cache flush operation (WBINVD) when
+ * entering C3 type state.
+ */
+ if (c->x86_vendor == X86_VENDOR_CENTAUR) {
+ if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
+ c->x86_stepping >= 0x0e))
+ flags->bm_check = 1;
+ }
+
+ if (c->x86_vendor == X86_VENDOR_ZHAOXIN) {
+ /*
+ * All Zhaoxin CPUs that support C3 share cache.
+ * And caches should not be flushed by software while
+ * entering C3 type state.
+ */
+ flags->bm_check = 1;
+ /*
+ * On all recent Zhaoxin platforms, ARB_DISABLE is a nop.
+ * So, set bm_control to zero to indicate that ARB_DISABLE
+ * is not required while entering C3 type state.
+ */
+ flags->bm_control = 0;
+ }
+ if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) {
+ /*
+ * For all AMD Zen or newer CPUs that support C3, caches
+ * should not be flushed by software while entering C3
+ * type state. Set bm->check to 1 so that kernel doesn't
+ * need to execute cache flush operation.
+ */
+ flags->bm_check = 1;
+ /*
+ * In current AMD C state implementation ARB_DIS is no longer
+ * used. So set bm_control to zero to indicate ARB_DIS is not
+ * required while entering C3 type state.
+ */
+ flags->bm_control = 0;
+ }
}
EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
--
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