From 2d4e7cfdeed82023d06f202af6e196b4e37a5342 Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@devjustinian.com>
Date: Sun, 29 Apr 2018 23:50:56 -0700
Subject: [PATCH] Check CPUID info, switch cpu flag to Broadwell

---
 Makefile            |  1 +
 src/kernel/cpu.cpp  | 63 +++++++++++++++++++++++++++++++++++++++++++++
 src/kernel/cpu.h    | 40 ++++++++++++++++++++++++++++
 src/kernel/main.cpp | 13 ++++++++++
 4 files changed, 117 insertions(+)
 create mode 100644 src/kernel/cpu.cpp
 create mode 100644 src/kernel/cpu.h

diff --git a/Makefile b/Makefile
index 1ade57a..332d234 100644
--- a/Makefile
+++ b/Makefile
@@ -116,6 +116,7 @@ QEMUOPTS       += -drive file=$(BUILD_D)/fs.img,format=raw
 QEMUOPTS       += -smp $(CPUS) -m 512
 QEMUOPTS       += -d mmu,guest_errors,int -D popcorn.log 
 QEMUOPTS       += -no-reboot
+QEMUOPTS       += -cpu Broadwell
 QEMUOPTS       += $(QEMUEXTRA)
 
 
diff --git a/src/kernel/cpu.cpp b/src/kernel/cpu.cpp
new file mode 100644
index 0000000..60d0f90
--- /dev/null
+++ b/src/kernel/cpu.cpp
@@ -0,0 +1,63 @@
+#include <stdint.h>
+#include "kutil/memory.h"
+#include "cpu.h"
+#include "log.h"
+
+inline static void
+__cpuid(
+	uint32_t leaf,
+	uint32_t subleaf,
+	uint32_t *eax,
+	uint32_t *ebx = nullptr,
+	uint32_t *ecx = nullptr,
+	uint32_t *edx = nullptr)
+{
+	uint32_t a, b, c, d;
+	__asm__ __volatile__ ( "cpuid"
+			: "=a"(a), "=b"(b), "=c"(c), "=d"(d)
+			: "a"(leaf), "c"(subleaf)
+			);
+	if (eax) *eax = a;
+	if (ebx) *ebx = b;
+	if (ecx) *ecx = c;
+	if (edx) *edx = d;
+}
+
+
+cpu_id::cpu_id()
+{
+	__cpuid(0, 0,
+		&m_high_leaf,
+		reinterpret_cast<uint32_t *>(&m_vendor_id[0]),
+		reinterpret_cast<uint32_t *>(&m_vendor_id[8]),
+		reinterpret_cast<uint32_t *>(&m_vendor_id[4]));
+
+	uint32_t eax = 0;
+	__cpuid(0, 1, &eax);
+
+	m_stepping = eax & 0xf;
+	m_model = (eax >> 4) & 0xf;
+	m_family = (eax >> 8) & 0xf;
+
+	m_cpu_type = (eax >> 12) & 0x3;
+
+	uint32_t ext_model = (eax >> 16) & 0xf;
+	uint32_t ext_family = (eax >> 20) & 0xff;
+
+	if (m_family == 0x6 || m_family == 0xf)
+		m_model = (ext_model << 4) + m_model;
+
+	if (m_family == 0xf)
+		m_family += ext_family;
+
+}
+
+cpu_id::regs
+cpu_id::get(uint32_t leaf, uint32_t sub) const
+{
+	if (leaf > m_high_leaf) return {};
+
+	regs ret;
+	__cpuid(leaf, sub, &ret.eax, &ret.ebx, &ret.ecx, &ret.edx);
+	return ret;
+}
diff --git a/src/kernel/cpu.h b/src/kernel/cpu.h
new file mode 100644
index 0000000..deaf68e
--- /dev/null
+++ b/src/kernel/cpu.h
@@ -0,0 +1,40 @@
+#pragma once
+
+
+class cpu_id
+{
+public:
+	struct regs {
+		uint32_t eax, ebx, ecx, edx;
+
+		regs() : eax(0), ebx(0), ecx(0), edx(0) {}
+		regs(uint32_t a, uint32_t b, uint32_t c, uint32_t d) : eax(a), ebx(b), ecx(c), edx(d) {}
+		regs(const regs &r) : eax(r.eax), ebx(r.ebx), ecx(r.ecx), edx(r.edx) {}
+
+		bool eax_bit(unsigned bit) { return (eax >> bit) & 0x1; }
+		bool ebx_bit(unsigned bit) { return (ebx >> bit) & 0x1; }
+		bool ecx_bit(unsigned bit) { return (ecx >> bit) & 0x1; }
+		bool edx_bit(unsigned bit) { return (edx >> bit) & 0x1; }
+	};
+
+	cpu_id();
+
+	regs get(uint32_t leaf, uint32_t sub = 0) const;
+
+	inline const char * vendor_id() const	{ return m_vendor_id; }
+	inline uint8_t cpu_type() const			{ return m_cpu_type; }
+	inline uint8_t stepping() const			{ return m_stepping; }
+	inline uint16_t family() const			{ return m_family; }
+	inline uint16_t model() const			{ return m_model; }
+
+private:
+	void read();
+
+	uint32_t m_high_leaf;
+	char m_vendor_id[13];
+
+	uint8_t m_cpu_type;
+	uint8_t m_stepping;
+	uint16_t m_family;
+	uint16_t m_model;
+};
diff --git a/src/kernel/main.cpp b/src/kernel/main.cpp
index 644d184..9f5ad58 100644
--- a/src/kernel/main.cpp
+++ b/src/kernel/main.cpp
@@ -3,6 +3,7 @@
 
 #include "kutil/memory.h"
 #include "console.h"
+#include "cpu.h"
 #include "device_manager.h"
 #include "font.h"
 #include "interrupts.h"
@@ -48,6 +49,18 @@ kernel_main(popcorn_data *header)
 
 	log::init(cons);
 
+	cpu_id cpu;
+
+	log::info(logs::boot, "CPU Vendor: %s", cpu.vendor_id());
+	log::info(logs::boot, "CPU Family %x Model %x Stepping %x",
+			cpu.family(), cpu.model(), cpu.stepping());
+
+	cpu_id::regs cpu_info = cpu.get(1);
+	log::info(logs::boot, "LAPIC Supported: %s",
+			cpu_info.edx_bit(9) ? "yes" : "no");
+	log::info(logs::boot, "x2APIC Supported: %s",
+			cpu_info.ecx_bit(21) ? "yes" : "no");
+
 	page_manager *pager = new (&g_page_manager) page_manager;
 	pager->mark_offset_pointer(&header->frame_buffer, header->frame_buffer_length);