From 57963c87d81a6c27f207bfd8881492ae783fa3df Mon Sep 17 00:00:00 2001
From: Brad Smith <brad@comstyle.com>
Date: Thu, 16 May 2024 23:52:33 -0400
Subject: [PATCH] Add OpenBSD/arm64 support.

Fix building on OpenBSD/arm64 and add CPU feature detection.
---
 Source/Core/Common/ArmCPUDetect.cpp | 42 +++++++++++++++++++++++++----
 Source/Core/Core/MachineContext.h   |  5 ++++
 2 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/Source/Core/Common/ArmCPUDetect.cpp b/Source/Core/Common/ArmCPUDetect.cpp
index b55952cf2b..84cf727695 100644
--- a/Source/Core/Common/ArmCPUDetect.cpp
+++ b/Source/Core/Common/ArmCPUDetect.cpp
@@ -15,11 +15,16 @@
 #include <Windows.h>
 #include <arm64intr.h>
 #include "Common/WindowsRegistry.h"
-#else
-#ifndef __FreeBSD__
+#elif defined(__linux__)
 #include <asm/hwcap.h>
-#endif
 #include <sys/auxv.h>
+#elif defined(__FreeBSD__)
+#include <sys/auxv.h>
+#elif defined(__OpenBSD__)
+#include <machine/armreg.h>
+#include <machine/cpu.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
 #endif
 
 #include <fmt/format.h>
@@ -183,7 +188,7 @@ static bool Read_MIDR_EL1(u64* value)
 
 #endif
 
-#ifndef __APPLE__
+#if defined(_WIN32) || defined(__linux__) || defined(__FreeBSD__)
 
 static std::string MIDRToString(u64 midr)
 {
@@ -248,7 +253,7 @@ void CPUInfo::Detect()
   {
     cpu_id = MIDRToString(reg);
   }
-#else
+#elif defined(__linux__) || defined(__FreeBSD__)
   // Linux, Android, and FreeBSD
 
 #if defined(__FreeBSD__)
@@ -277,6 +282,33 @@ void CPUInfo::Detect()
   {
     cpu_id = MIDRToString(midr);
   }
+#elif defined(__OpenBSD__)
+  // OpenBSD
+  int mib[2];
+  size_t len;
+  char hwmodel[256];
+  uint64_t isar0;
+
+  mib[0] = CTL_HW;
+  mib[1] = HW_MODEL;
+  len = std::size(hwmodel);
+  if (sysctl(mib, 2, &hwmodel, &len, nullptr, 0) != -1)
+    model_name = std::string(hwmodel, len - 1);
+
+  mib[0] = CTL_MACHDEP;
+  mib[1] = CPU_ID_AA64ISAR0;
+  len = sizeof(isar0);
+  if (sysctl(mib, 2, &isar0, &len, nullptr, 0) != -1)
+  {
+    if (ID_AA64ISAR0_AES(isar0) >= ID_AA64ISAR0_AES_BASE)
+      bAES = true;
+    if (ID_AA64ISAR0_SHA1(isar0) >= ID_AA64ISAR0_SHA1_BASE)
+      bSHA1 = true;
+    if (ID_AA64ISAR0_SHA2(isar0) >= ID_AA64ISAR0_SHA2_BASE)
+      bSHA2 = true;
+    if (ID_AA64ISAR0_CRC32(isar0) >= ID_AA64ISAR0_CRC32_BASE)
+      bCRC32 = true;
+  }
 #endif
 
   model_name = ReplaceAll(model_name, ",", "_");
diff --git a/Source/Core/Core/MachineContext.h b/Source/Core/Core/MachineContext.h
index 9d20c51ef3..8d93cf3f3f 100644
--- a/Source/Core/Core/MachineContext.h
+++ b/Source/Core/Core/MachineContext.h
@@ -157,6 +157,11 @@ typedef ucontext_t SContext;
 #define CTX_R14 sc_r14
 #define CTX_R15 sc_r15
 #define CTX_RIP sc_rip
+#elif _M_ARM_64
+#define CTX_REG(x) sc_x[x]
+#define CTX_LR sc_lr
+#define CTX_SP sc_sp
+#define CTX_PC sc_elr
 #else
 #error No context definition for architecture
 #endif