[PATCH v6 06/20] xen/bitops: put __ffs() and ffz() into linux compatible header

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

The mentioned macros exist only because of Linux compatible purpose.

The patch defines __ffs() in terms of Xen bitops and it is safe
to define in this way ( as __ffs() - 1 ) as considering that __ffs()
was defined as __builtin_ctzl(x), which has undefined behavior when x=0,
so it is assumed that such cases are not encountered in the current code.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V6:
 - new patch for the patch series.
---
 xen/arch/arm/include/asm/arm64/bitops.h | 21 ---------------------
 xen/arch/ppc/include/asm/bitops.h       | 21 ---------------------
 xen/drivers/passthrough/arm/smmu-v3.c   |  2 ++
 xen/include/xen/linux-compat.h          |  3 +++
 xen/lib/find-next-bit.c                 |  1 +
 5 files changed, 6 insertions(+), 42 deletions(-)

diff --git a/xen/arch/arm/include/asm/arm64/bitops.h 
b/xen/arch/arm/include/asm/arm64/bitops.h
index 5f5d97faa0..2deb134388 100644
--- a/xen/arch/arm/include/asm/arm64/bitops.h
+++ b/xen/arch/arm/include/asm/arm64/bitops.h
@@ -1,27 +1,6 @@
 #ifndef _ARM_ARM64_BITOPS_H
 #define _ARM_ARM64_BITOPS_H
 
-/* Based on linux/include/asm-generic/bitops/builtin-__ffs.h */
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static /*__*/always_inline unsigned long __ffs(unsigned long word)
-{
-        return __builtin_ctzl(word);
-}
-
-/* Based on linux/include/asm-generic/bitops/ffz.h */
-/*
- * ffz - find first zero in word.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-#define ffz(x)  __ffs(~(x))
-
 static inline int arch_flsl(unsigned long x)
 {
         uint64_t ret;
diff --git a/xen/arch/ppc/include/asm/bitops.h 
b/xen/arch/ppc/include/asm/bitops.h
index 16447a4be6..fd157f3632 100644
--- a/xen/arch/ppc/include/asm/bitops.h
+++ b/xen/arch/ppc/include/asm/bitops.h
@@ -171,15 +171,6 @@ static inline int __test_and_clear_bit(int nr, volatile 
void *addr)
     return (old & mask) != 0;
 }
 
-/* Based on linux/include/asm-generic/bitops/ffz.h */
-/*
- * ffz - find first zero in word.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-#define ffz(x) __ffs(~(x))
-
 /**
  * hweightN - returns the hamming weight of a N-bit word
  * @x: the word to weigh
@@ -191,16 +182,4 @@ static inline int __test_and_clear_bit(int nr, volatile 
void *addr)
 #define hweight16(x) __builtin_popcount((uint16_t)(x))
 #define hweight8(x)  __builtin_popcount((uint8_t)(x))
 
-/* Based on linux/include/asm-generic/bitops/builtin-__ffs.h */
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static always_inline unsigned long __ffs(unsigned long word)
-{
-    return __builtin_ctzl(word);
-}
-
 #endif /* _ASM_PPC_BITOPS_H */
diff --git a/xen/drivers/passthrough/arm/smmu-v3.c 
b/xen/drivers/passthrough/arm/smmu-v3.c
index b1c40c2c0a..6904962467 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -72,12 +72,14 @@
  */
 
 #include <xen/acpi.h>
+#include <xen/bitops.h>
 #include <xen/config.h>
 #include <xen/delay.h>
 #include <xen/errno.h>
 #include <xen/err.h>
 #include <xen/irq.h>
 #include <xen/lib.h>
+#include <xen/linux-compat.h>
 #include <xen/list.h>
 #include <xen/mm.h>
 #include <xen/rbtree.h>
diff --git a/xen/include/xen/linux-compat.h b/xen/include/xen/linux-compat.h
index 62ba71485c..de059bdf12 100644
--- a/xen/include/xen/linux-compat.h
+++ b/xen/include/xen/linux-compat.h
@@ -19,4 +19,7 @@ typedef int64_t __s64;
 
 typedef paddr_t phys_addr_t;
 
+#define __ffs(x) (ffsl(x) - 1)
+#define ffz(x) __ffs(~(x))
+
 #endif /* __XEN_LINUX_COMPAT_H__ */
diff --git a/xen/lib/find-next-bit.c b/xen/lib/find-next-bit.c
index ca6f82277e..b151f7f994 100644
--- a/xen/lib/find-next-bit.c
+++ b/xen/lib/find-next-bit.c
@@ -9,6 +9,7 @@
  * 2 of the License, or (at your option) any later version.
  */
 #include <xen/bitops.h>
+#include <xen/linux-compat.h>
 
 #include <asm/byteorder.h>
 
-- 
2.43.0