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.
To not include <xen/linux-compat.h> to Xen library files __ffs() and __ffz()
were defined locally in find-next-bit.c.
Except __ffs() usage in find-next-bit.c only one usage of __ffs() leave
in smmu-v3.c. It seems that it __ffs can be changed to ffsl(x)-1 in
this file, but to keep smmu-v3.c looks close to linux it was deciced just
to define __ffs() in xen/linux-compat.h and include it in smmu-v3.c
Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
---
Changes in V7:
- introduce ffz(),__ffs() locally in find-next-bit.c
- drop inclusion of <xen/linux-compat.h> in find-next-bit.c.
- update the commit message.
---
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 | 12 ------------
xen/drivers/passthrough/arm/smmu-v3.c | 2 ++
xen/include/xen/linux-compat.h | 2 ++
xen/lib/find-next-bit.c | 3 +++
5 files changed, 7 insertions(+), 33 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 a17060c7c2..2237b9f8f4 100644
--- a/xen/arch/ppc/include/asm/bitops.h
+++ b/xen/arch/ppc/include/asm/bitops.h
@@ -130,16 +130,4 @@ static inline int test_and_set_bit(unsigned 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..10db80df57 100644
--- a/xen/include/xen/linux-compat.h
+++ b/xen/include/xen/linux-compat.h
@@ -19,4 +19,6 @@ typedef int64_t __s64;
typedef paddr_t phys_addr_t;
+#define __ffs(x) (ffsl(x) - 1)
+
#endif /* __XEN_LINUX_COMPAT_H__ */
diff --git a/xen/lib/find-next-bit.c b/xen/lib/find-next-bit.c
index ca6f82277e..761b027398 100644
--- a/xen/lib/find-next-bit.c
+++ b/xen/lib/find-next-bit.c
@@ -12,6 +12,9 @@
#include <asm/byteorder.h>
+#define __ffs(x) (ffsl(x) - 1)
+#define ffz(x) __ffs(~(x))
+
#ifndef find_next_bit
/*
* Find the next set bit in a memory region.
--
2.43.0
