From f7af9c3316153ed43ec784fecf0e548cd5deff88 Mon Sep 17 00:00:00 2001
From: Ash Logan <ash@heyquark.com>
Date: Mon, 22 Apr 2019 10:12:28 +1000
Subject: [PATCH] include/coreinit: First pass at coreinit/codegen.h

---
 include/coreinit/codegen.h                    | 128 ++++++++++++++++++
 .../test_compile_headers_list.h               |   1 +
 2 files changed, 129 insertions(+)
 create mode 100644 include/coreinit/codegen.h

diff --git a/include/coreinit/codegen.h b/include/coreinit/codegen.h
new file mode 100644
index 0000000..893d55d
--- /dev/null
+++ b/include/coreinit/codegen.h
@@ -0,0 +1,128 @@
+#pragma once
+#include <wut.h>
+
+/**
+ * \defgroup coreinit_codegen Codegen
+ * \ingroup coreinit
+ *
+ * Controls a memory area that can switch between writable and
+ * executable states, allowing dynamic code generation.
+ * For some applications, a codegen area is avilable for things like JIT or
+ * otherwise generating CPU instructions on the fly. Enabled apps can use
+ * \link OSCodegenGetVirtAddrRange \endlink to discover this area, then use
+ * \link OSSwitchSecCodeGenMode \endlink or \link OSCodegenCopy \endlink to
+ * move instructions in and out before executing them. Codegen can only be used
+ * from a specific, predetermined CPU core - see
+ * \link OSGetCodegenCore \endlink. Codegen can only be used when enabled in an
+ * app's cos.xml.
+ *
+ * <!-- TODO mark up cos.xml permission requirements, figure out sizing -->
+ * <!--
+ *  sources:
+ *  https://web.archive.org/web/20190327131828/https://wiiubrew.org/wiki/Coreinit.rpl#Codegen
+ *  https://web.archive.org/web/20190421120656/https://github.com/decaf-emu/decaf-emu/blob/master/src/libdecaf/src/cafe/libraries/coreinit/coreinit_codegen.cpp
+ * -->
+ * @{
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//! The memory permissions for the codegen area.
+typedef enum OSCodegenSecMode
+{
+    //! The area can be read or written to, but not executed.
+    CODEGEN_RW_ = 0,
+    //! The area can be read or executed, but not written to.
+    CODEGEN_R_X = 1,
+} OSCodegenSecMode;
+
+/**
+ * Gets the location and size of codegen memory, if available.
+ *
+ * \param outVirtualAddress
+ * Pointer to write the virtual address of the codegen area to. Will write 0 if
+ * codegen isn't available.
+ *
+ * \param outSize
+ * Pointer to write the size of the codegen area to. Will write 0 if codegen
+ * isn't available.
+ *
+ * \sa
+ * - \link OSGetSecCodeGenMode \endlink
+ */
+void
+OSCodegenGetVirtAddrRange(uint32_t* outVirtualAddress,
+                          uint32_t* outSize);
+
+/**
+ * Gets the CPU core that's allowed to use codegen.
+ *
+ * \return
+ * The core id of the core that can use codegen.
+ *
+ * \sa
+ * - \link OSGetCoreId \endlink
+ *
+ * <!-- NOTE this appears to come from cos.xml: bottom few bits -->
+ */
+uint32_t
+OSGetCodegenCore();
+
+uint32_t
+OSGetCodegenMode();
+
+/**
+ * Switches the permissions on the codegen memory area. Use this function to
+ * move between writing code and executing it.
+ *
+ * \param mode
+ * The memory permission mode to use - one of \link OSCodegenSecMode \endlink.
+ *
+ * \returns
+ * \c true on success, or \c false on a failure, such as codegen not being
+ * available for this app or CPU core.
+ */
+BOOL
+OSSwitchSecCodeGenMode(OSCodegenSecMode mode);
+
+//TODO: online docs imply this returns true if codegen is *enabled*, though the
+//name would imply it gets rw/rx status.
+uint32_t
+OSGetSecCodeGenMode();
+
+/**
+ * Copies data from normal memory into the codegen area, leaving the area in
+ * \link CODEGEN_R_X \endlink mode.
+ * This function copies into the codegen area regardless
+ * of the current permission status by switching modes as required for the copy.
+ *
+ * \param dst
+ * The starting virtual address of the area in codegen memory to copy to. Must
+ * be a valid pointer
+ *
+ * \param src
+ * The starting virtual address of the source to copy from. Must be a valid
+ * pointer.
+ *
+ * \param size
+ * The size of the data to copy. Must not be 0, and must be small
+ * enough such that <tt>dst + size</tt> does not pass the end of the codegen
+ * area (see \link OSCodegenGetVirtAddrRange \endlink).
+ *
+ * \return
+ * \c TRUE on success, indicating the codegen area is now in
+ * \link CODEGEN_R_X \endlink, or \c FALSE on an error, such as invalid pointers
+ * or codegen not being available.
+ *
+ * <!-- NOTE this function has a specific bit required in cox.xml: 1 << 30? -->
+ */
+BOOL
+OSCodegenCopy(void* dst, void* src, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
diff --git a/tests/test_compile_headers_common/test_compile_headers_list.h b/tests/test_compile_headers_common/test_compile_headers_list.h
index ef9ffcd..dde4168 100644
--- a/tests/test_compile_headers_common/test_compile_headers_list.h
+++ b/tests/test_compile_headers_common/test_compile_headers_list.h
@@ -3,6 +3,7 @@
 #include <coreinit/atomic.h>
 #include <coreinit/atomic64.h>
 #include <coreinit/cache.h>
+#include <coreinit/codegen.h>
 #include <coreinit/condition.h>
 #include <coreinit/context.h>
 #include <coreinit/core.h>