Revert "xen: make include/xen/unaligned.h usable on all architectures"

This breaks gitlab CI:

https://gitlab.com/xen-project/hardware/xen/-/jobs/5733143618

This reverts commit 6c4be49503.

xen/include/xen/unaligned.h

@@ -1,4 +1,12 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This header can be used by architectures where unaligned accesses work
+ * without faulting, and at least reasonably efficiently.  Other architectures
+ * will need to have a custom asm/unaligned.h.
+ */
+#ifndef __ASM_UNALIGNED_H__
+#error "xen/unaligned.h should not be included directly - include asm/unaligned.h instead"
+#endif
+
 #ifndef __XEN_UNALIGNED_H__
 #define __XEN_UNALIGNED_H__
 
@@ -7,82 +15,67 @@
 #include <asm/byteorder.h>
 #endif
 
-/*
- * This is the most generic implementation of unaligned accesses
- * and should work almost anywhere.
- */
-
-#define get_unaligned_t(type, ptr) ({					\
-	const struct { type x; } __packed *ptr_ = (typeof(ptr_))(ptr);	\
-	ptr_->x;							\
-})
-
-#define put_unaligned_t(type, val, ptr) do {				\
-	struct { type x; } __packed *ptr_ = (typeof(ptr_))(ptr);	\
-	ptr_->x = val;							\
-} while (0)
-
-#define get_unaligned(ptr)	get_unaligned_t(typeof(*(ptr)), ptr)
-#define put_unaligned(val, ptr) put_unaligned_t(typeof(*(ptr)), val, ptr)
+#define get_unaligned(p) (*(p))
+#define put_unaligned(val, p) (*(p) = (val))
 
 static inline uint16_t get_unaligned_be16(const void *p)
 {
-	return be16_to_cpu(get_unaligned_t(__be16, p));
+	return be16_to_cpup(p);
 }
 
 static inline void put_unaligned_be16(uint16_t val, void *p)
 {
-	put_unaligned_t(__be16, cpu_to_be16(val), p);
+	*(__force __be16*)p = cpu_to_be16(val);
 }
 
 static inline uint32_t get_unaligned_be32(const void *p)
 {
-	return be32_to_cpu(get_unaligned_t(__be32, p));
+	return be32_to_cpup(p);
 }
 
 static inline void put_unaligned_be32(uint32_t val, void *p)
 {
-	put_unaligned_t(__be32, cpu_to_be32(val), p);
+	*(__force __be32*)p = cpu_to_be32(val);
 }
 
 static inline uint64_t get_unaligned_be64(const void *p)
 {
-	return be64_to_cpu(get_unaligned_t(__be64, p));
+	return be64_to_cpup(p);
 }
 
 static inline void put_unaligned_be64(uint64_t val, void *p)
 {
-	put_unaligned_t(__be64, cpu_to_be64(val), p);
+	*(__force __be64*)p = cpu_to_be64(val);
 }
 
 static inline uint16_t get_unaligned_le16(const void *p)
 {
-	return le16_to_cpu(get_unaligned_t(__le16, p));
+	return le16_to_cpup(p);
 }
 
 static inline void put_unaligned_le16(uint16_t val, void *p)
 {
-	put_unaligned_t(__le16, cpu_to_le16(val), p);
+	*(__force __le16*)p = cpu_to_le16(val);
 }
 
 static inline uint32_t get_unaligned_le32(const void *p)
 {
-	return le32_to_cpu(get_unaligned_t(__le32, p));
+	return le32_to_cpup(p);
 }
 
 static inline void put_unaligned_le32(uint32_t val, void *p)
 {
-	put_unaligned_t(__le32, cpu_to_le32(val), p);
+	*(__force __le32*)p = cpu_to_le32(val);
 }
 
 static inline uint64_t get_unaligned_le64(const void *p)
 {
-	return le64_to_cpu(get_unaligned_t(__le64, p));
+	return le64_to_cpup(p);
 }
 
 static inline void put_unaligned_le64(uint64_t val, void *p)
 {
-	put_unaligned_t(__le64, cpu_to_le64(val), p);
+	*(__force __le64*)p = cpu_to_le64(val);
 }
 
 #endif /* __XEN_UNALIGNED_H__ */