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/cpu/mtrr/generic.c | 24 ++++++++++++++++++------
1 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/kernel/arch/x86/kernel/cpu/mtrr/generic.c b/kernel/arch/x86/kernel/cpu/mtrr/generic.c
index 9436f34..a29997e 100644
--- a/kernel/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/kernel/arch/x86/kernel/cpu/mtrr/generic.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* This only handles 32bit MTRR on 32bit hosts. This is strictly wrong
* because MTRRs can span up to 40 bits (36bits on most modern x86)
@@ -14,7 +15,7 @@
#include <asm/tlbflush.h>
#include <asm/mtrr.h>
#include <asm/msr.h>
-#include <asm/pat.h>
+#include <asm/memtype.h>
#include "mtrr.h"
@@ -742,7 +743,15 @@
/* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */
cr0 = read_cr0() | X86_CR0_CD;
write_cr0(cr0);
- wbinvd();
+
+ /*
+ * Cache flushing is the most time-consuming step when programming
+ * the MTRRs. Fortunately, as per the Intel Software Development
+ * Manual, we can skip it if the processor supports cache self-
+ * snooping.
+ */
+ if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
+ wbinvd();
/* Save value of CR4 and clear Page Global Enable (bit 7) */
if (boot_cpu_has(X86_FEATURE_PGE)) {
@@ -752,21 +761,24 @@
/* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
- __flush_tlb();
+ flush_tlb_local();
/* Save MTRR state */
rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
/* Disable MTRRs, and set the default type to uncached */
mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & ~0xcff, deftype_hi);
- wbinvd();
+
+ /* Again, only flush caches if we have to. */
+ if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
+ wbinvd();
}
static void post_set(void) __releases(set_atomicity_lock)
{
/* Flush TLBs (no need to flush caches - they are disabled) */
count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
- __flush_tlb();
+ flush_tlb_local();
/* Intel (P6) standard MTRRs */
mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
@@ -798,7 +810,7 @@
local_irq_restore(flags);
/* Use the atomic bitops to update the global mask */
- for (count = 0; count < sizeof mask * 8; ++count) {
+ for (count = 0; count < sizeof(mask) * 8; ++count) {
if (mask & 0x01)
set_bit(count, &smp_changes_mask);
mask >>= 1;
--
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