[PATCH] lib/decompress_unxz.c: removing all memory helper functions

@@ -9,6 +9,7 @@
 extern unsigned long free_mem_ptr;
 extern unsigned long free_mem_end_ptr;
 extern void error(char *);
+extern int memcmp(const void *, const void *, size_t);
 
 #define STATIC static
 #define STATIC_RW_DATA	/* non-static please */

@@ -45,8 +46,6 @@ extern void error(char *);
 #endif
 
 #ifdef CONFIG_KERNEL_XZ
-#define memmove memmove
-#define memcpy memcpy
 #include "../../../../lib/decompress_unxz.c"
 #endif
 

@@ -87,6 +87,20 @@ void *memcpy(void *__dest, __const void *__src, size_t __n)
 	return __builtin_memcpy(__dest, __src, __n);
 }
 
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+	const unsigned char *su1, *su2;
+	int res = 0;
+
+	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) {
+		res = *su1 - *su2;
+		if (res != 0)
+			break;
+	}
+
+	return res;
+}
+
 void *memmove(void *__dest, __const void *__src, size_t __n)
 {
 	char *d;

@@ -94,6 +94,38 @@ void* memcpy(void* __dest, __const void* __src,
 	return __dest;
 }
 
+void *memmove(void *dest, const void *src, size_t size)
+{
+	uint8_t *d = dest;
+	const uint8_t *s = src;
+	size_t i;
+
+	if (d < s) {
+		for (i = 0; i < size; ++i)
+			d[i] = s[i];
+	} else if (d > s) {
+		i = size;
+		while (i-- > 0)
+			d[i] = s[i];
+	}
+
+	return dest;
+}
+
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+	const unsigned char *su1, *su2;
+	int res = 0;
+
+	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) {
+		res = *su1 - *su2;
+		if (res != 0)
+			break;
+	}
+
+	return res;
+}
+
 static void error(char *x)
 {
 	puts("\n\n");

@@ -8,4 +8,22 @@ int memcmp(const void *s1, const void *s2, size_t len)
 	return diff;
 }
 
+void *memmove(void *dest, const void *src, size_t size)
+{
+	uint8_t *d = dest;
+	const uint8_t *s = src;
+	size_t i;
+
+	if (d < s) {
+		for (i = 0; i < size; ++i)
+			d[i] = s[i];
+	} else if (d > s) {
+		i = size;
+		while (i-- > 0)
+			d[i] = s[i];
+	}
+
+	return dest;
+}
+
 #include "../string.c"

@@ -160,75 +160,24 @@
 #define vfree(ptr) do { if (ptr != NULL) free(ptr); } while (0)
 
 /*
- * FIXME: Not all basic memory functions are provided in architecture-specific
- * files (yet). We define our own versions here for now, but this should be
- * only a temporary solution.
+ * To support XZ-decompressed file in preboot environment, the following
+ * functions, memcmp, memset, memcpy and memmove, needed to be defined in
+ * architecture-specific preboot environment.
+ *
+ * Not all architecture-specific preboot environment currently support all of
+ * the above functions.
+ *
+ * If your architecture does not support any of the above functions, simply
+ * add the missing function(s) to the architecture-specific preboot string.c
+ * or misc.c file, for example arch/x86/boot/compressed/string.c for the x86
+ * architecture.
+ *
+ * memcmp is not used much and any remotely sane implementation is fast enough.
+ * memmove speed matters in multi-call mode.  Any missing memory helper
+ * functions, including a decent implementation of an in-place memmove function
+ * could be found in lib/string.c
  *
- * memeq and memzero are not used much and any remotely sane implementation
- * is fast enough. memcpy/memmove speed matters in multi-call mode, but
- * the kernel image is decompressed in single-call mode, in which only
- * memcpy speed can matter and only if there is a lot of uncompressible data
- * (LZMA2 stores uncompressible chunks in uncompressed form). Thus, the
- * functions below should just be kept small; it's probably not worth
- * optimizing for speed.
- */
-
-#ifndef memeq
-static bool memeq(const void *a, const void *b, size_t size)
-{
-	const uint8_t *x = a;
-	const uint8_t *y = b;
-	size_t i;
-
-	for (i = 0; i < size; ++i)
-		if (x[i] != y[i])
-			return false;
-
-	return true;
-}
-#endif
-
-#ifndef memzero
-static void memzero(void *buf, size_t size)
-{
-	uint8_t *b = buf;
-	uint8_t *e = b + size;
-
-	while (b != e)
-		*b++ = '\0';
-}
-#endif
-
-#ifndef memmove
-/* Not static to avoid a conflict with the prototype in the Linux headers. */
-void *memmove(void *dest, const void *src, size_t size)
-{
-	uint8_t *d = dest;
-	const uint8_t *s = src;
-	size_t i;
-
-	if (d < s) {
-		for (i = 0; i < size; ++i)
-			d[i] = s[i];
-	} else if (d > s) {
-		i = size;
-		while (i-- > 0)
-			d[i] = s[i];
-	}
-
-	return dest;
-}
-#endif
-
-/*
- * Since we need memmove anyway, would use it as memcpy too.
- * Commented out for now to avoid breaking things.
  */
-/*
-#ifndef memcpy
-#	define memcpy memmove
-#endif
-*/
 
 #include "xz/xz_crc32.c"
 #include "xz/xz_dec_stream.c"

@@ -37,9 +37,12 @@
 #		ifdef CONFIG_XZ_DEC_SPARC
 #			define XZ_DEC_SPARC
 #		endif
-#		define memeq(a, b, size) (memcmp(a, b, size) == 0)
-#		define memzero(buf, size) memset(buf, 0, size)
 #	endif
+	/* Make all environments, including preboot, use memcmp for memeq */
+#	define memeq(a, b, size) (memcmp(a, b, size) == 0)
+	/* To suppress redefine warning in some architecture's preboot */
+#	undef memzero
+#	define memzero(buf, size) memset(buf, 0, size)
 #	define get_le32(p) le32_to_cpup((const uint32_t *)(p))
 #else
 	/*