From 703de2c28415accc089a569cee79938cd2f2be69 Mon Sep 17 00:00:00 2001
From: Alex <enderice2@users.noreply.github.com>
Date: Wed, 12 Oct 2022 02:29:30 +0300
Subject: [PATCH] Enable CPU features like SSE

---
 Kernel.cpp | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/Kernel.cpp b/Kernel.cpp
index b0cba88..1671158 100644
--- a/Kernel.cpp
+++ b/Kernel.cpp
@@ -60,8 +60,54 @@ EXTERNC void Entry(BootInfo *Info)
     KPrint("Time: \e8888FF%02d:%02d:%02d %02d/%02d/%02d UTC",
            BootClock.Hour, BootClock.Minute, BootClock.Second,
            BootClock.Day, BootClock.Month, BootClock.Year);
+    KPrint("CPU: \e8822AA%s \e8888FF%s (\e058C19%s\e8888FF)", CPU::Vendor(), CPU::Name(), CPU::Hypervisor());
     KPrint("Initializing GDT and IDT");
     Interrupts::Initialize();
+    KPrint("Initializing CPU features");
+#if defined(__amd64__)
+    CPU::x64::CR0 cr0 = CPU::x64::readcr0();
+    CPU::x64::CR4 cr4 = CPU::x64::readcr4();
+    uint32_t rax, rbx, rcx, rdx;
+    CPU::x64::cpuid(1, &rax, &rbx, &rcx, &rdx);
+    if (rdx & CPU::x64::CPUID_FEAT_RDX_SSE)
+    {
+        debug("Enabling SSE support...");
+        KPrint("SSE is supported.");
+        cr0.EM = 0;
+        cr0.MP = 1;
+        cr4.OSFXSR = 1;
+        cr4.OSXMMEXCPT = 1;
+    }
+
+    // Enable cpu cache but... how to use it?
+    cr0.NW = 0;
+    cr0.CD = 0;
+
+    debug("Enabling UMIP, SMEP & SMAP support...");
+    CPU::x64::cpuid(1, &rax, &rbx, &rcx, &rdx);
+    if (rdx & CPU::x64::CPUID_FEAT_RDX_UMIP)
+    {
+        KPrint("UMIP is supported.");
+        fixme("Not going to enable UMIP.");
+        // cr4.UMIP = 1;
+    }
+    if (rdx & CPU::x64::CPUID_FEAT_RDX_SMEP)
+    {
+        KPrint("SMEP is supported.");
+        cr4.SMEP = 1;
+    }
+    if (rdx & CPU::x64::CPUID_FEAT_RDX_SMAP)
+    {
+        KPrint("SMAP is supported.");
+        cr4.SMAP = 1;
+    }
+    CPU::x64::writecr0(cr0);
+    CPU::x64::writecr4(cr4);
+    debug("Enabling PAT support...");
+    CPU::x64::wrmsr(CPU::x64::MSR_CR_PAT, 0x6 | (0x0 << 8) | (0x1 << 16));
+#elif defined(__i386__)
+#elif defined(__aarch64__)
+#endif
     KPrint("Loading kernel symbols");
     KernelSymbolTable = new SymbolResolver::Symbols((uint64_t)Info->Kernel.FileBase);
     KPrint("Initializing Power Manager");