These functions can be useful for architectures that don't
have corresponding arch-specific instructions.
Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
---
Changes in V5:
- new patch
---
xen/include/asm-generic/bitops/__ffs.h | 47 +++++++++++++++++++
xen/include/asm-generic/bitops/ffs.h | 9 ++++
xen/include/asm-generic/bitops/ffsl.h | 16 +++++++
.../asm-generic/bitops/find-first-set-bit.h | 17 +++++++
4 files changed, 89 insertions(+)
create mode 100644 xen/include/asm-generic/bitops/__ffs.h
create mode 100644 xen/include/asm-generic/bitops/ffs.h
create mode 100644 xen/include/asm-generic/bitops/ffsl.h
create mode 100644 xen/include/asm-generic/bitops/find-first-set-bit.h
diff --git a/xen/include/asm-generic/bitops/__ffs.h
b/xen/include/asm-generic/bitops/__ffs.h
new file mode 100644
index 0000000000..fecb4484d9
--- /dev/null
+++ b/xen/include/asm-generic/bitops/__ffs.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS___FFS_H_
+#define _ASM_GENERIC_BITOPS___FFS_H_
+
+/**
+ * ffs - find first bit in word.
+ * @word: The word to search
+ *
+ * Returns 0 if no bit exists, otherwise returns 1-indexed bit location.
+ */
+static inline unsigned int __ffs(unsigned long word)
+{
+ unsigned int num = 0;
+
+#if BITS_PER_LONG == 64
+ if ( (word & 0xffffffff) == 0 )
+ {
+ num += 32;
+ word >>= 32;
+ }
+#endif
+ if ( (word & 0xffff) == 0 )
+ {
+ num += 16;
+ word >>= 16;
+ }
+ if ( (word & 0xff) == 0 )
+ {
+ num += 8;
+ word >>= 8;
+ }
+ if ( (word & 0xf) == 0 )
+ {
+ num += 4;
+ word >>= 4;
+ }
+ if ( (word & 0x3) == 0 )
+ {
+ num += 2;
+ word >>= 2;
+ }
+ if ( (word & 0x1) == 0 )
+ num += 1;
+ return num;
+}
+
+#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
diff --git a/xen/include/asm-generic/bitops/ffs.h
b/xen/include/asm-generic/bitops/ffs.h
new file mode 100644
index 0000000000..3f75fded14
--- /dev/null
+++ b/xen/include/asm-generic/bitops/ffs.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS_FFS_H_
+#define _ASM_GENERIC_BITOPS_FFS_H_
+
+#include <xen/macros.h>
+
+#define ffs(x) ({ unsigned int t_ = (x); fls(ISOLATE_LSB(t_)); })
+
+#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
diff --git a/xen/include/asm-generic/bitops/ffsl.h
b/xen/include/asm-generic/bitops/ffsl.h
new file mode 100644
index 0000000000..d0996808f5
--- /dev/null
+++ b/xen/include/asm-generic/bitops/ffsl.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS_FFSL_H_
+#define _ASM_GENERIC_BITOPS_FFSL_H_
+
+/**
+ * ffsl - find first bit in long.
+ * @word: The word to search
+ *
+ * Returns 0 if no bit exists, otherwise returns 1-indexed bit location.
+ */
+static inline unsigned int ffsl(unsigned long word)
+{
+ return generic_ffsl(word);
+}
+
+#endif /* _ASM_GENERIC_BITOPS_FFSL_H_ */
diff --git a/xen/include/asm-generic/bitops/find-first-set-bit.h
b/xen/include/asm-generic/bitops/find-first-set-bit.h
new file mode 100644
index 0000000000..7d28b8a89b
--- /dev/null
+++ b/xen/include/asm-generic/bitops/find-first-set-bit.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS_FIND_FIRST_SET_BIT_H_
+#define _ASM_GENERIC_BITOPS_FIND_FIRST_SET_BIT_H_
+
+/**
+ * find_first_set_bit - find the first set bit in @word
+ * @word: the word to search
+ *
+ * Returns the bit-number of the first set bit (first bit being 0).
+ * The input must *not* be zero.
+ */
+static inline unsigned int find_first_set_bit(unsigned long word)
+{
+ return ffsl(word) - 1;
+}
+
+#endif /* _ASM_GENERIC_BITOPS_FIND_FIRST_SET_BIT_H_ */
--
2.43.0
