Changes to kernel_args to make it identical for x86 and x86_64.

* Added a FixedWidthPointer template class which uses 64-bit storage to hold a pointer. This is used in place of raw pointers in kernel_args. * Added __attribute__((packed)) to kernel_args and all structures contained within it. This is necessary due to different alignment behaviour for 32-bit and 64-bit compilation with GCC. * With these changes, kernel_args will now come out the same size for both the x86_64 kernel and the loader, excluding the preloaded_image structure which has not yet been changed. * Tested both an x86 GCC2 and GCC4 build, no problems caused by these changes.
2012-06-21 18:02:23 +01:00
parent 192af9e0af
commit d8efc6caf6
21 changed files with 174 additions and 41 deletions
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2012, Alex Smith, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef KERNEL_UTIL_FIXED_WIDTH_POINTER_H
+#define KERNEL_UTIL_FIXED_WIDTH_POINTER_H
+
+
+#include <SupportDefs.h>
+
+
+/*!
+	\class FixedWidthPointer
+	\brief Pointer class with fixed size (64-bit) storage.
+
+	This class is a pointer-like class that uses a fixed size 64-bit storage.
+	This is used to make kernel_args compatible (i.e. the same size) for both
+	32-bit and 64-bit kernels.
+*/
+template<typename Type>
+class FixedWidthPointer {
+public:
+	operator Type*() const
+	{
+		return (Type *)(addr_t)fValue;
+	}
+
+	operator addr_t() const
+	{
+		return (addr_t)fValue;
+	}
+
+	Type &operator*() const
+	{
+		return *(Type *)*this;
+	}
+
+	Type *operator->() const
+	{
+		return *this;
+	}
+
+	FixedWidthPointer &operator=(const FixedWidthPointer &p)
+	{
+		fValue = p.fValue;
+		return *this;
+	}
+
+	FixedWidthPointer &operator=(Type *p)
+	{
+		fValue = (addr_t)p;
+		return *this;
+	}
+
+	/*!
+		Get the 64-bit pointer value.
+		\return Pointer address.
+	*/
+	uint64 Get() const
+	{
+		return fValue;
+	}
+
+	/*!
+		Set the 64-bit pointer value.
+		\param addr New address for the pointer.
+	*/
+	void SetTo(uint64 addr)
+	{
+		fValue = addr;
+	}
+private:
+	uint64 fValue;
+} _PACKED;
+
+
+// Specialization for void pointers, can be converted to another pointer type.
+template<>
+class FixedWidthPointer<void> {
+public:
+	operator void*() const
+	{
+		return (void *)(addr_t)fValue;
+	}
+
+	template<typename OtherType>
+	operator OtherType*() const
+	{
+		return (OtherType *)(addr_t)fValue;
+	}
+
+	operator addr_t() const
+	{
+		return (addr_t)fValue;
+	}
+
+	FixedWidthPointer &operator=(const FixedWidthPointer &p)
+	{
+		fValue = p.fValue;
+		return *this;
+	}
+
+	FixedWidthPointer &operator=(void *p)
+	{
+		fValue = (addr_t)p;
+		return *this;
+	}
+
+	uint64 Get() const
+	{
+		return fValue;
+	}
+
+	void SetTo(uint64 addr)
+	{
+		fValue = addr;
+	}
+private:
+	uint64 fValue;
+} _PACKED;
+
+
+#endif	/* KERNEL_UTIL_FIXED_WIDTH_POINTER_H */