[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 16/34] xen/lib: introduce generic find next bit operations
find-next-bit.c is common for Arm64 and RISC-V64 so it is moved to xen/lib. Suggested-by: Jan Beulich <jbeulich@xxxxxxxx> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> --- Changes in V3: - new patch. --- xen/arch/riscv/include/asm/fence.h | 11 +- xen/common/Kconfig | 3 + xen/lib/Makefile | 1 + xen/lib/find-next-bit.c | 281 +++++++++++++++++++++++++++++ 4 files changed, 295 insertions(+), 1 deletion(-) create mode 100644 xen/lib/find-next-bit.c diff --git a/xen/arch/riscv/include/asm/fence.h b/xen/arch/riscv/include/asm/fence.h index b3f6b1c20a..5d9a851ae8 100644 --- a/xen/arch/riscv/include/asm/fence.h +++ b/xen/arch/riscv/include/asm/fence.h @@ -1,4 +1,4 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* SPDX-License-Identifier: GPL-2.0-only */ #ifndef _ASM_RISCV_FENCE_H #define _ASM_RISCV_FENCE_H @@ -11,3 +11,12 @@ #endif #endif /* _ASM_RISCV_FENCE_H */ + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ diff --git a/xen/common/Kconfig b/xen/common/Kconfig index 310ad4229c..56ce34ffd4 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -47,6 +47,9 @@ config ARCH_MAP_DOMAIN_PAGE config GENERIC_BUG_FRAME bool +config GENERIC_FIND_NEXT_BIT + bool + config HAS_ALTERNATIVE bool diff --git a/xen/lib/Makefile b/xen/lib/Makefile index 2d9ebb945f..66237a45c5 100644 --- a/xen/lib/Makefile +++ b/xen/lib/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_X86) += x86/ lib-y += bsearch.o lib-y += ctors.o lib-y += ctype.o +lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find-next-bit.o lib-y += list-sort.o lib-y += memchr.o lib-y += memchr_inv.o diff --git a/xen/lib/find-next-bit.c b/xen/lib/find-next-bit.c new file mode 100644 index 0000000000..ca6f82277e --- /dev/null +++ b/xen/lib/find-next-bit.c @@ -0,0 +1,281 @@ +/* find_next_bit.c: fallback find next bit implementation + * + * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <xen/bitops.h> + +#include <asm/byteorder.h> + +#ifndef find_next_bit +/* + * Find the next set bit in a memory region. + */ +unsigned long find_next_bit(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + const unsigned long *p = addr + BIT_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); +} +EXPORT_SYMBOL(find_next_bit); +#endif + +#ifndef find_next_zero_bit +/* + * This implementation of find_{first,next}_zero_bit was stolen from + * Linus' asm-alpha/bitops.h. + */ +unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + const unsigned long *p = addr + BIT_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); +} +EXPORT_SYMBOL(find_next_zero_bit); +#endif + +#ifndef find_first_bit +/* + * Find the first set bit in a memory region. + */ +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); +} +EXPORT_SYMBOL(find_first_bit); +#endif + +#ifndef find_first_zero_bit +/* + * Find the first cleared bit in a memory region. + */ +unsigned long find_first_zero_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 << size); + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. */ +found: + return result + ffz(tmp); +} +EXPORT_SYMBOL(find_first_zero_bit); +#endif + +#ifdef __BIG_ENDIAN + +/* include/linux/byteorder does not support "unsigned long" type */ +static inline unsigned long ext2_swabp(const unsigned long * x) +{ +#if BITS_PER_LONG == 64 + return (unsigned long) __swab64p((u64 *) x); +#elif BITS_PER_LONG == 32 + return (unsigned long) __swab32p((u32 *) x); +#else +#error BITS_PER_LONG not defined +#endif +} + +/* include/linux/byteorder doesn't support "unsigned long" type */ +static inline unsigned long ext2_swab(const unsigned long y) +{ +#if BITS_PER_LONG == 64 + return (unsigned long) __swab64((u64) y); +#elif BITS_PER_LONG == 32 + return (unsigned long) __swab32((u32) y); +#else +#error BITS_PER_LONG not defined +#endif +} + +#ifndef find_next_zero_bit_le +unsigned long find_next_zero_bit_le(const void *addr, unsigned + long size, unsigned long offset) +{ + const unsigned long *p = addr; + unsigned long result = offset & ~(BITS_PER_LONG - 1); + unsigned long tmp; + + if (offset >= size) + return size; + p += BIT_WORD(offset); + size -= result; + offset &= (BITS_PER_LONG - 1UL); + if (offset) { + tmp = ext2_swabp(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_swap; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = ext2_swabp(p); +found_first: + tmp |= ~0UL << size; + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. Skip ffz */ +found_middle: + return result + ffz(tmp); + +found_middle_swap: + return result + ffz(ext2_swab(tmp)); +} +EXPORT_SYMBOL(find_next_zero_bit_le); +#endif + +#ifndef find_next_bit_le +unsigned long find_next_bit_le(const void *addr, unsigned + long size, unsigned long offset) +{ + const unsigned long *p = addr; + unsigned long result = offset & ~(BITS_PER_LONG - 1); + unsigned long tmp; + + if (offset >= size) + return size; + p += BIT_WORD(offset); + size -= result; + offset &= (BITS_PER_LONG - 1UL); + if (offset) { + tmp = ext2_swabp(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)) { + tmp = *(p++); + if (tmp) + goto found_middle_swap; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = ext2_swabp(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); + +found_middle_swap: + return result + __ffs(ext2_swab(tmp)); +} +EXPORT_SYMBOL(find_next_bit_le); +#endif + +#endif /* __BIG_ENDIAN */ -- 2.43.0
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |