asm: convert the ARM implementation of bit operations to the reference

The implementation of bit operations for ARM isn't actually
architecture-specific so it would rather be shared with
the upcoming port for AArch64 that won't provide optimized
implementation of bit operations.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Reviewed-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/arm/include/asm/bitops.h

-#ifndef __CR_BITOPS_H__
-#define __CR_BITOPS_H__
+#ifndef __CR_ASM_BITOPS_H__
+#define __CR_ASM_BITOPS_H__
 
-#include "asm/bitsperlong.h"
+#include "compiler.h"
+#include "asm-generic/bitops.h"
 
-#define DIV_ROUND_UP(n,d)	(((n) + (d) - 1) / (d))
-#define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_LONG)
-
-#define DECLARE_BITMAP(name, bits)		\
-	unsigned long name[BITS_TO_LONGS(bits)]
-
-#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1)
-/* Technically wrong, but this avoids compilation errors on some gcc
-   versions. */
-#define BITOP_ADDR(x) "=m" (*(volatile long *) (x))
-#else
-#define BITOP_ADDR(x) "+m" (*(volatile long *) (x))
-#endif
-
-#define ADDR				BITOP_ADDR(addr)
-
-static inline void set_bit(int nr, volatile unsigned long *addr) {
-	addr += nr / BITS_PER_LONG;
-	*addr |= (1 << (nr % BITS_PER_LONG));
-}
-
-static inline void change_bit(int nr, volatile unsigned long *addr)
-{
-	addr += nr / BITS_PER_LONG;
-	*addr ^= (1 << (nr % BITS_PER_LONG));
-}
-
-static inline int test_bit(int nr, volatile const unsigned long *addr)
-{
-	addr += nr / BITS_PER_LONG;
-	return (*addr & (1 << (nr % BITS_PER_LONG))) ? -1 : 0;
-}
-
-static inline void clear_bit(int nr, volatile unsigned long *addr)
-{
-	addr += nr / BITS_PER_LONG;
-	*addr &= ~(1 << (nr % BITS_PER_LONG));
-}
-
-/**
- * __ffs - find first set bit in word
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static inline unsigned long __ffs(unsigned long word)
-{
-	int p = 0;
-
-	for (; p < 8*sizeof(word); ++p) {
-		if (word & 1) {
-			break;
-		}
-
-		word >>= 1;
-	}
-
-	return p;
-}
-
-#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
-
-/*
- * Find the next set bit in a memory region.
- */
-static inline
-unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
-			    unsigned long offset)
-{
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG-1);
-	unsigned long tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset %= BITS_PER_LONG;
-	if (offset) {
-		tmp = *(p++);
-		tmp &= (~0UL << offset);
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
-	}
-	while (size & ~(BITS_PER_LONG-1)) {
-		if ((tmp = *(p++)))
-			goto found_middle;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
-	}
-	if (!size)
-		return result;
-	tmp = *p;
-
-found_first:
-	tmp &= (~0UL >> (BITS_PER_LONG - size));
-	if (tmp == 0UL)		/* Are any bits set? */
-		return result + size;	/* Nope. */
-found_middle:
-	return result + __ffs(tmp);
-}
-
-#define for_each_bit(i, bitmask)				\
-	for (i = find_next_bit(bitmask, sizeof(bitmask), 0);	\
-	     i < sizeof(bitmask);				\
-	     i = find_next_bit(bitmask, sizeof(bitmask), i + 1))
-
-#endif /* __CR_BITOPS_H__ */
+#endif /* __CR_ASM_BITOPS_H__ */

include/asm-generic/bitops.h

+#ifndef __CR_GENERIC_BITOPS_H__
+#define __CR_GENERIC_BITOPS_H__
+
+#include "asm/bitsperlong.h"
+
+#define DIV_ROUND_UP(n,d)	(((n) + (d) - 1) / (d))
+#define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_LONG)
+
+#define DECLARE_BITMAP(name, bits)		\
+	unsigned long name[BITS_TO_LONGS(bits)]
+
+#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1)
+/* Technically wrong, but this avoids compilation errors on some gcc
+   versions. */
+#define BITOP_ADDR(x) "=m" (*(volatile long *) (x))
+#else
+#define BITOP_ADDR(x) "+m" (*(volatile long *) (x))
+#endif
+
+#define ADDR				BITOP_ADDR(addr)
+
+static inline void set_bit(int nr, volatile unsigned long *addr) {
+	addr += nr / BITS_PER_LONG;
+	*addr |= (1 << (nr % BITS_PER_LONG));
+}
+
+static inline void change_bit(int nr, volatile unsigned long *addr)
+{
+	addr += nr / BITS_PER_LONG;
+	*addr ^= (1 << (nr % BITS_PER_LONG));
+}
+
+static inline int test_bit(int nr, volatile const unsigned long *addr)
+{
+	addr += nr / BITS_PER_LONG;
+	return (*addr & (1 << (nr % BITS_PER_LONG))) ? -1 : 0;
+}
+
+static inline void clear_bit(int nr, volatile unsigned long *addr)
+{
+	addr += nr / BITS_PER_LONG;
+	*addr &= ~(1 << (nr % BITS_PER_LONG));
+}
+
+/**
+ * __ffs - find first set bit in word
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+	int p = 0;
+
+	for (; p < 8*sizeof(word); ++p) {
+		if (word & 1) {
+			break;
+		}
+
+		word >>= 1;
+	}
+
+	return p;
+}
+
+#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
+
+/*
+ * Find the next set bit in a memory region.
+ */
+static inline
+unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
+			    unsigned long offset)
+{
+	const unsigned long *p = addr + BITOP_WORD(offset);
+	unsigned long result = offset & ~(BITS_PER_LONG-1);
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (offset) {
+		tmp = *(p++);
+		tmp &= (~0UL << offset);
+		if (size < BITS_PER_LONG)
+			goto found_first;
+		if (tmp)
+			goto found_middle;
+		size -= BITS_PER_LONG;
+		result += BITS_PER_LONG;
+	}
+	while (size & ~(BITS_PER_LONG-1)) {
+		if ((tmp = *(p++)))
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+
+found_first:
+	tmp &= (~0UL >> (BITS_PER_LONG - size));
+	if (tmp == 0UL)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found_middle:
+	return result + __ffs(tmp);
+}
+
+#define for_each_bit(i, bitmask)				\
+	for (i = find_next_bit(bitmask, sizeof(bitmask), 0);	\
+	     i < sizeof(bitmask);				\
+	     i = find_next_bit(bitmask, sizeof(bitmask), i + 1))
+
+#endif /* __CR_GENERIC_BITOPS_H__ */