docs/misra/exclude-list.json | 8 +-
xen/arch/arm/arm64/lib/Makefile | 2 +-
xen/arch/arm/include/asm/arm64/bitops.h | 46 +------
xen/arch/ppc/include/asm/bitops.h | 115 ------------------
xen/include/xen/bitops.h | 48 ++++++++
xen/lib/Makefile | 1 +
.../find_next_bit.c => lib/find-next-bit.c} | 0
7 files changed, 55 insertions(+), 165 deletions(-)
rename xen/{arch/arm/arm64/lib/find_next_bit.c => lib/find-next-bit.c} (100%)
find-next-bit.c is common for Arm64, PPC and RISCV64,
so it is moved to xen/lib.
PPC has been transitioned to generic functions from find-next-bit.c
since it now shares the same implementation as the PPC-specific code.
The MISRA exclude list has been updated to verify
lib/find-next-bit.c instead of Arm's find_next_bit.c,
as Arm's find_next_bit.c has been relocated to xen/lib/.
Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in
Xen and being removed from the Linux kernel [1], it could theoretically
prove useful for Xen. This is because the Linux kernel transitioned
Arm to the generic version of find_first_bit() and
find_first_zero_bit() due to improvements [1] in both performance
and .text size.
It would be prudent to investigate whether [1] is applicable to Xen
as well and, if so, implement the necessary changes in a separate patch.
[1] https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---
docs/misra/exclude-list.json | 8 +-
xen/arch/arm/arm64/lib/Makefile | 2 +-
xen/arch/arm/include/asm/arm64/bitops.h | 46 +------
xen/arch/ppc/include/asm/bitops.h | 115 ------------------
xen/include/xen/bitops.h | 48 ++++++++
xen/lib/Makefile | 1 +
.../find_next_bit.c => lib/find-next-bit.c} | 0
7 files changed, 55 insertions(+), 165 deletions(-)
rename xen/{arch/arm/arm64/lib/find_next_bit.c => lib/find-next-bit.c} (100%)
diff --git a/docs/misra/exclude-list.json b/docs/misra/exclude-list.json
index 7971d0e70f..b28174d0eb 100644
--- a/docs/misra/exclude-list.json
+++ b/docs/misra/exclude-list.json
@@ -13,10 +13,6 @@
"rel_path": "arch/arm/arm64/insn.c",
"comment": "Imported on Linux, ignore for now"
},
- {
- "rel_path": "arch/arm/arm64/lib/find_next_bit.c",
- "comment": "Imported from Linux, ignore for now"
- },
{
"rel_path": "arch/x86/acpi/boot.c",
"comment": "Imported from Linux, ignore for now"
@@ -221,6 +217,10 @@
"rel_path": "include/xen/decompress.h",
"comment": "Imported from Linux, ignore for now"
},
+ {
+ "rel_path": "lib/find-next-bit.c",
+ "comment": "Imported from Linux, ignore for now"
+ },
{
"rel_path": "lib/list-sort.c",
"comment": "Imported from Linux, ignore for now"
diff --git a/xen/arch/arm/arm64/lib/Makefile b/xen/arch/arm/arm64/lib/Makefile
index 1b9c7a95e6..66cfac435a 100644
--- a/xen/arch/arm/arm64/lib/Makefile
+++ b/xen/arch/arm/arm64/lib/Makefile
@@ -1,4 +1,4 @@
obj-y += memcpy.o memcmp.o memmove.o memset.o memchr.o
obj-y += clear_page.o
-obj-y += bitops.o find_next_bit.o
+obj-y += bitops.o
obj-y += strchr.o strcmp.o strlen.o strncmp.o strnlen.o strrchr.o
diff --git a/xen/arch/arm/include/asm/arm64/bitops.h b/xen/arch/arm/include/asm/arm64/bitops.h
index d85a49bca4..0efde29068 100644
--- a/xen/arch/arm/include/asm/arm64/bitops.h
+++ b/xen/arch/arm/include/asm/arm64/bitops.h
@@ -36,57 +36,13 @@ static inline int flsl(unsigned long x)
/* Based on linux/include/asm-generic/bitops/find.h */
-#ifndef find_next_bit
-/**
- * find_next_bit - find the next set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The bitmap size in bits
- */
-extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
- size, unsigned long offset);
-#endif
-
-#ifndef find_next_zero_bit
-/**
- * find_next_zero_bit - find the next cleared bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The bitmap size in bits
- */
-extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
- long size, unsigned long offset);
-#endif
-
-#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
-
-/**
- * find_first_bit - find the first set bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit number of the first set bit.
- */
-extern unsigned long find_first_bit(const unsigned long *addr,
- unsigned long size);
-
-/**
- * find_first_zero_bit - find the first cleared bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit number of the first cleared bit.
- */
-extern unsigned long find_first_zero_bit(const unsigned long *addr,
- unsigned long size);
-#else /* CONFIG_GENERIC_FIND_FIRST_BIT */
+#ifndef CONFIG_GENERIC_FIND_FIRST_BIT
#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
-
#endif /* _ARM_ARM64_BITOPS_H */
/*
* Local variables:
diff --git a/xen/arch/ppc/include/asm/bitops.h b/xen/arch/ppc/include/asm/bitops.h
index 5e7f36c21d..5820b9ce7b 100644
--- a/xen/arch/ppc/include/asm/bitops.h
+++ b/xen/arch/ppc/include/asm/bitops.h
@@ -217,119 +217,4 @@ static always_inline unsigned long __ffs(unsigned long word)
*/
#define find_first_set_bit(x) (ffsl(x) - 1)
-/*
- * Find the first set bit in a memory region.
- */
-static inline unsigned long find_first_bit(const unsigned long *addr,
- unsigned long size)
-{
- const unsigned long *p = addr;
- unsigned long result = 0;
- unsigned long tmp;
-
- while ( size & ~(BITS_PER_LONG - 1) )
- {
- if ( (tmp = *(p++)) )
- goto found;
- result += BITS_PER_LONG;
- size -= BITS_PER_LONG;
- }
- if ( !size )
- return result;
-
- tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
- if ( tmp == 0UL ) /* Are any bits set? */
- return result + size; /* Nope. */
- found:
- return result + __ffs(tmp);
-}
-
-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);
-}
-
-/*
- * This implementation of find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h.
- */
-static inline unsigned long find_next_zero_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 >> (BITS_PER_LONG - 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 << size;
- if ( tmp == ~0UL ) /* Are any bits zero? */
- return result + size; /* Nope. */
- found_middle:
- return result + ffz(tmp);
-}
-
#endif /* _ASM_PPC_BITOPS_H */
diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
index 2cb7892bcc..e3c5a4ccf3 100644
--- a/xen/include/xen/bitops.h
+++ b/xen/include/xen/bitops.h
@@ -105,6 +105,54 @@ static inline int generic_flsl(unsigned long x)
*/
#include <asm/bitops.h>
+#ifndef find_next_bit
+/**
+ * find_next_bit - find the next set bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ */
+extern unsigned long find_next_bit(const unsigned long *addr,
+ unsigned long size,
+ unsigned long offset);
+#endif
+
+#ifndef find_next_zero_bit
+/**
+ * find_next_zero_bit - find the next cleared bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ */
+extern unsigned long find_next_zero_bit(const unsigned long *addr,
+ unsigned long size,
+ unsigned long offset);
+#endif
+
+#ifndef find_first_bit
+/**
+ * find_first_bit - find the first set bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit number of the first set bit.
+ */
+extern unsigned long find_first_bit(const unsigned long *addr,
+ unsigned long size);
+#endif
+
+#ifndef find_first_zero_bit
+/**
+ * find_first_zero_bit - find the first cleared bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit number of the first cleared bit.
+ */
+extern unsigned long find_first_zero_bit(const unsigned long *addr,
+ unsigned long size);
+#endif
+
#if BITS_PER_LONG == 64
# define fls64 flsl
# define ffs64 ffsl
diff --git a/xen/lib/Makefile b/xen/lib/Makefile
index 2d9ebb945f..e63798e1d4 100644
--- a/xen/lib/Makefile
+++ b/xen/lib/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_X86) += x86/
lib-y += bsearch.o
lib-y += ctors.o
lib-y += ctype.o
+lib-y += find-next-bit.o
lib-y += list-sort.o
lib-y += memchr.o
lib-y += memchr_inv.o
diff --git a/xen/arch/arm/arm64/lib/find_next_bit.c b/xen/lib/find-next-bit.c
similarity index 100%
rename from xen/arch/arm/arm64/lib/find_next_bit.c
rename to xen/lib/find-next-bit.c
--
2.43.0Hi Oleksii, On 09/02/2024 17:58, Oleksii Kurochko wrote: > find-next-bit.c is common for Arm64, PPC and RISCV64, > so it is moved to xen/lib. > > PPC has been transitioned to generic functions from find-next-bit.c > since it now shares the same implementation as the PPC-specific code. > > The MISRA exclude list has been updated to verify > lib/find-next-bit.c instead of Arm's find_next_bit.c, > as Arm's find_next_bit.c has been relocated to xen/lib/. > > Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in > Xen and being removed from the Linux kernel [1], it could theoretically > prove useful for Xen. This is because the Linux kernel transitioned > Arm to the generic version of find_first_bit() and > find_first_zero_bit() due to improvements [1] in both performance > and .text size. > It would be prudent to investigate whether [1] is applicable to Xen > as well and, if so, implement the necessary changes in a separate patch. > > [1] https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/ > > Suggested-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> This is now committed. Cheers, -- Julien Grall
Hi Shawn,
Could you please take a look at the patch and PPC-related changes (
xen/arch/ppc/include/asm/bitops.h )?
Thanks in advance.
~ Oleksii
On Fri, 2024-02-09 at 18:58 +0100, Oleksii Kurochko wrote:
> find-next-bit.c is common for Arm64, PPC and RISCV64,
> so it is moved to xen/lib.
>
> PPC has been transitioned to generic functions from find-next-bit.c
> since it now shares the same implementation as the PPC-specific code.
>
> The MISRA exclude list has been updated to verify
> lib/find-next-bit.c instead of Arm's find_next_bit.c,
> as Arm's find_next_bit.c has been relocated to xen/lib/.
>
> Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in
> Xen and being removed from the Linux kernel [1], it could
> theoretically
> prove useful for Xen. This is because the Linux kernel transitioned
> Arm to the generic version of find_first_bit() and
> find_first_zero_bit() due to improvements [1] in both performance
> and .text size.
> It would be prudent to investigate whether [1] is applicable to Xen
> as well and, if so, implement the necessary changes in a separate
> patch.
>
> [1]
> https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/
>
> Suggested-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> ---
> docs/misra/exclude-list.json | 8 +-
> xen/arch/arm/arm64/lib/Makefile | 2 +-
> xen/arch/arm/include/asm/arm64/bitops.h | 46 +------
> xen/arch/ppc/include/asm/bitops.h | 115 ----------------
> --
> xen/include/xen/bitops.h | 48 ++++++++
> xen/lib/Makefile | 1 +
> .../find_next_bit.c => lib/find-next-bit.c} | 0
> 7 files changed, 55 insertions(+), 165 deletions(-)
> rename xen/{arch/arm/arm64/lib/find_next_bit.c => lib/find-next-
> bit.c} (100%)
>
> diff --git a/docs/misra/exclude-list.json b/docs/misra/exclude-
> list.json
> index 7971d0e70f..b28174d0eb 100644
> --- a/docs/misra/exclude-list.json
> +++ b/docs/misra/exclude-list.json
> @@ -13,10 +13,6 @@
> "rel_path": "arch/arm/arm64/insn.c",
> "comment": "Imported on Linux, ignore for now"
> },
> - {
> - "rel_path": "arch/arm/arm64/lib/find_next_bit.c",
> - "comment": "Imported from Linux, ignore for now"
> - },
> {
> "rel_path": "arch/x86/acpi/boot.c",
> "comment": "Imported from Linux, ignore for now"
> @@ -221,6 +217,10 @@
> "rel_path": "include/xen/decompress.h",
> "comment": "Imported from Linux, ignore for now"
> },
> + {
> + "rel_path": "lib/find-next-bit.c",
> + "comment": "Imported from Linux, ignore for now"
> + },
> {
> "rel_path": "lib/list-sort.c",
> "comment": "Imported from Linux, ignore for now"
> diff --git a/xen/arch/arm/arm64/lib/Makefile
> b/xen/arch/arm/arm64/lib/Makefile
> index 1b9c7a95e6..66cfac435a 100644
> --- a/xen/arch/arm/arm64/lib/Makefile
> +++ b/xen/arch/arm/arm64/lib/Makefile
> @@ -1,4 +1,4 @@
> obj-y += memcpy.o memcmp.o memmove.o memset.o memchr.o
> obj-y += clear_page.o
> -obj-y += bitops.o find_next_bit.o
> +obj-y += bitops.o
> obj-y += strchr.o strcmp.o strlen.o strncmp.o strnlen.o strrchr.o
> diff --git a/xen/arch/arm/include/asm/arm64/bitops.h
> b/xen/arch/arm/include/asm/arm64/bitops.h
> index d85a49bca4..0efde29068 100644
> --- a/xen/arch/arm/include/asm/arm64/bitops.h
> +++ b/xen/arch/arm/include/asm/arm64/bitops.h
> @@ -36,57 +36,13 @@ static inline int flsl(unsigned long x)
>
> /* Based on linux/include/asm-generic/bitops/find.h */
>
> -#ifndef find_next_bit
> -/**
> - * find_next_bit - find the next set bit in a memory region
> - * @addr: The address to base the search on
> - * @offset: The bitnumber to start searching at
> - * @size: The bitmap size in bits
> - */
> -extern unsigned long find_next_bit(const unsigned long *addr,
> unsigned long
> - size, unsigned long offset);
> -#endif
> -
> -#ifndef find_next_zero_bit
> -/**
> - * find_next_zero_bit - find the next cleared bit in a memory region
> - * @addr: The address to base the search on
> - * @offset: The bitnumber to start searching at
> - * @size: The bitmap size in bits
> - */
> -extern unsigned long find_next_zero_bit(const unsigned long *addr,
> unsigned
> - long size, unsigned long offset);
> -#endif
> -
> -#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
> -
> -/**
> - * find_first_bit - find the first set bit in a memory region
> - * @addr: The address to start the search at
> - * @size: The maximum size to search
> - *
> - * Returns the bit number of the first set bit.
> - */
> -extern unsigned long find_first_bit(const unsigned long *addr,
> - unsigned long size);
> -
> -/**
> - * find_first_zero_bit - find the first cleared bit in a memory
> region
> - * @addr: The address to start the search at
> - * @size: The maximum size to search
> - *
> - * Returns the bit number of the first cleared bit.
> - */
> -extern unsigned long find_first_zero_bit(const unsigned long *addr,
> - unsigned long size);
> -#else /* CONFIG_GENERIC_FIND_FIRST_BIT */
> +#ifndef CONFIG_GENERIC_FIND_FIRST_BIT
>
> #define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
> #define find_first_zero_bit(addr, size) find_next_zero_bit((addr),
> (size), 0)
>
> #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
>
> -
> #endif /* _ARM_ARM64_BITOPS_H */
> /*
> * Local variables:
> diff --git a/xen/arch/ppc/include/asm/bitops.h
> b/xen/arch/ppc/include/asm/bitops.h
> index 5e7f36c21d..5820b9ce7b 100644
> --- a/xen/arch/ppc/include/asm/bitops.h
> +++ b/xen/arch/ppc/include/asm/bitops.h
> @@ -217,119 +217,4 @@ static always_inline unsigned long
> __ffs(unsigned long word)
> */
> #define find_first_set_bit(x) (ffsl(x) - 1)
>
> -/*
> - * Find the first set bit in a memory region.
> - */
> -static inline unsigned long find_first_bit(const unsigned long
> *addr,
> - unsigned long size)
> -{
> - const unsigned long *p = addr;
> - unsigned long result = 0;
> - unsigned long tmp;
> -
> - while ( size & ~(BITS_PER_LONG - 1) )
> - {
> - if ( (tmp = *(p++)) )
> - goto found;
> - result += BITS_PER_LONG;
> - size -= BITS_PER_LONG;
> - }
> - if ( !size )
> - return result;
> -
> - tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
> - if ( tmp == 0UL ) /* Are any bits set? */
> - return result + size; /* Nope. */
> - found:
> - return result + __ffs(tmp);
> -}
> -
> -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);
> -}
> -
> -/*
> - * This implementation of find_{first,next}_zero_bit was stolen from
> - * Linus' asm-alpha/bitops.h.
> - */
> -static inline unsigned long find_next_zero_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 >> (BITS_PER_LONG - 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 << size;
> - if ( tmp == ~0UL ) /* Are any bits zero? */
> - return result + size; /* Nope. */
> - found_middle:
> - return result + ffz(tmp);
> -}
> -
> #endif /* _ASM_PPC_BITOPS_H */
> diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h
> index 2cb7892bcc..e3c5a4ccf3 100644
> --- a/xen/include/xen/bitops.h
> +++ b/xen/include/xen/bitops.h
> @@ -105,6 +105,54 @@ static inline int generic_flsl(unsigned long x)
> */
> #include <asm/bitops.h>
>
> +#ifndef find_next_bit
> +/**
> + * find_next_bit - find the next set bit in a memory region
> + * @addr: The address to base the search on
> + * @offset: The bitnumber to start searching at
> + * @size: The bitmap size in bits
> + */
> +extern unsigned long find_next_bit(const unsigned long *addr,
> + unsigned long size,
> + unsigned long offset);
> +#endif
> +
> +#ifndef find_next_zero_bit
> +/**
> + * find_next_zero_bit - find the next cleared bit in a memory region
> + * @addr: The address to base the search on
> + * @offset: The bitnumber to start searching at
> + * @size: The bitmap size in bits
> + */
> +extern unsigned long find_next_zero_bit(const unsigned long *addr,
> + unsigned long size,
> + unsigned long offset);
> +#endif
> +
> +#ifndef find_first_bit
> +/**
> + * find_first_bit - find the first set bit in a memory region
> + * @addr: The address to start the search at
> + * @size: The maximum size to search
> + *
> + * Returns the bit number of the first set bit.
> + */
> +extern unsigned long find_first_bit(const unsigned long *addr,
> + unsigned long size);
> +#endif
> +
> +#ifndef find_first_zero_bit
> +/**
> + * find_first_zero_bit - find the first cleared bit in a memory
> region
> + * @addr: The address to start the search at
> + * @size: The maximum size to search
> + *
> + * Returns the bit number of the first cleared bit.
> + */
> +extern unsigned long find_first_zero_bit(const unsigned long *addr,
> + unsigned long size);
> +#endif
> +
> #if BITS_PER_LONG == 64
> # define fls64 flsl
> # define ffs64 ffsl
> diff --git a/xen/lib/Makefile b/xen/lib/Makefile
> index 2d9ebb945f..e63798e1d4 100644
> --- a/xen/lib/Makefile
> +++ b/xen/lib/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_X86) += x86/
> lib-y += bsearch.o
> lib-y += ctors.o
> lib-y += ctype.o
> +lib-y += find-next-bit.o
> lib-y += list-sort.o
> lib-y += memchr.o
> lib-y += memchr_inv.o
> diff --git a/xen/arch/arm/arm64/lib/find_next_bit.c b/xen/lib/find-
> next-bit.c
> similarity index 100%
> rename from xen/arch/arm/arm64/lib/find_next_bit.c
> rename to xen/lib/find-next-bit.c
Hi Oleksii, On 2/20/24 9:20 AM, Oleksii wrote: > Hi Shawn, > > Could you please take a look at the patch and PPC-related changes ( > xen/arch/ppc/include/asm/bitops.h )? > Hi Oleksii, Sorry for the delay. This all looks good to me: Acked-by: Shawn Anastasio <sanastasio@raptorengineering.com> > Thanks in advance. > > ~ Oleksii Thanks, Shawn
Hi Oleksii, On 09/02/2024 17:58, Oleksii Kurochko wrote: > find-next-bit.c is common for Arm64, PPC and RISCV64, > so it is moved to xen/lib. > > PPC has been transitioned to generic functions from find-next-bit.c > since it now shares the same implementation as the PPC-specific code. > > The MISRA exclude list has been updated to verify > lib/find-next-bit.c instead of Arm's find_next_bit.c, > as Arm's find_next_bit.c has been relocated to xen/lib/. > > Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in > Xen and being removed from the Linux kernel [1], it could theoretically > prove useful for Xen. This is because the Linux kernel transitioned > Arm to the generic version of find_first_bit() and > find_first_zero_bit() due to improvements [1] in both performance > and .text size. > It would be prudent to investigate whether [1] is applicable to Xen > as well and, if so, implement the necessary changes in a separate patch. > > [1] https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/ > > Suggested-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> Reviewed-by: Julien Grall <jgrall@amazon.com> Cheers, -- Julien Grall
Hi Julien, On Tue, 2024-02-13 at 17:18 +0000, Julien Grall wrote: > Hi Oleksii, > > On 09/02/2024 17:58, Oleksii Kurochko wrote: > > find-next-bit.c is common for Arm64, PPC and RISCV64, > > so it is moved to xen/lib. > > > > PPC has been transitioned to generic functions from find-next-bit.c > > since it now shares the same implementation as the PPC-specific > > code. > > > > The MISRA exclude list has been updated to verify > > lib/find-next-bit.c instead of Arm's find_next_bit.c, > > as Arm's find_next_bit.c has been relocated to xen/lib/. > > > > Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in > > Xen and being removed from the Linux kernel [1], it could > > theoretically > > prove useful for Xen. This is because the Linux kernel transitioned > > Arm to the generic version of find_first_bit() and > > find_first_zero_bit() due to improvements [1] in both performance > > and .text size. > > It would be prudent to investigate whether [1] is applicable to Xen > > as well and, if so, implement the necessary changes in a separate > > patch. > > > > [1] > > https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/ > > > > Suggested-by: Jan Beulich <jbeulich@suse.com> > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> > > Reviewed-by: Julien Grall <jgrall@amazon.com> Thanks for review. ~ Oleksii
On 09.02.2024 18:58, Oleksii Kurochko wrote: > find-next-bit.c is common for Arm64, PPC and RISCV64, > so it is moved to xen/lib. > > PPC has been transitioned to generic functions from find-next-bit.c > since it now shares the same implementation as the PPC-specific code. > > The MISRA exclude list has been updated to verify > lib/find-next-bit.c instead of Arm's find_next_bit.c, > as Arm's find_next_bit.c has been relocated to xen/lib/. > > Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in > Xen and being removed from the Linux kernel [1], it could theoretically > prove useful for Xen. This is because the Linux kernel transitioned > Arm to the generic version of find_first_bit() and > find_first_zero_bit() due to improvements [1] in both performance > and .text size. > It would be prudent to investigate whether [1] is applicable to Xen > as well and, if so, implement the necessary changes in a separate patch. > > [1] https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/ > > Suggested-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> A revision log would have been nice, though. Jan
On Mon, 2024-02-12 at 15:15 +0100, Jan Beulich wrote: > On 09.02.2024 18:58, Oleksii Kurochko wrote: > > find-next-bit.c is common for Arm64, PPC and RISCV64, > > so it is moved to xen/lib. > > > > PPC has been transitioned to generic functions from find-next-bit.c > > since it now shares the same implementation as the PPC-specific > > code. > > > > The MISRA exclude list has been updated to verify > > lib/find-next-bit.c instead of Arm's find_next_bit.c, > > as Arm's find_next_bit.c has been relocated to xen/lib/. > > > > Despite CONFIG_GENERIC_FIND_FIRST_BIT not currently being used in > > Xen and being removed from the Linux kernel [1], it could > > theoretically > > prove useful for Xen. This is because the Linux kernel transitioned > > Arm to the generic version of find_first_bit() and > > find_first_zero_bit() due to improvements [1] in both performance > > and .text size. > > It would be prudent to investigate whether [1] is applicable to Xen > > as well and, if so, implement the necessary changes in a separate > > patch. > > > > [1] > > https://lore.kernel.org/linux-arch/20211005054059.475634-5-yury.norov@gmail.com/ > > > > Suggested-by: Jan Beulich <jbeulich@suse.com> > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> > > Reviewed-by: Jan Beulich <jbeulich@suse.com> Thanks! > > A revision log would have been nice, though. Missed that. In case if it will be needed a new patch version, I'll back the log. ~ Oleksii
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