x86: generic versions of find_first_(zero_)bit, convert i386
Generic versions of __find_first_bit and __find_first_zero_bit are introduced as simplified versions of __find_next_bit and __find_next_zero_bit. Their compilation and use are guarded by a new config variable GENERIC_FIND_FIRST_BIT. The generic versions of find_first_bit and find_first_zero_bit are implemented in terms of the newly introduced __find_first_bit and __find_first_zero_bit. This patch does not remove the i386-specific implementation, but it does switch i386 to use the generic functions by setting GENERIC_FIND_FIRST_BIT=y for X86_32. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -77,6 +77,9 @@ config GENERIC_BUG
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def_bool y
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def_bool y
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depends on BUG
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depends on BUG
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config GENERIC_FIND_FIRST_BIT
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def_bool X86_32
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config GENERIC_FIND_NEXT_BIT
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config GENERIC_FIND_NEXT_BIT
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def_bool y
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def_bool y
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@ -5,6 +5,7 @@
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* Copyright 1992, Linus Torvalds.
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* Copyright 1992, Linus Torvalds.
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*/
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*/
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#ifndef CONFIG_GENERIC_FIND_FIRST_BIT
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/**
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/**
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* find_first_zero_bit - find the first zero bit in a memory region
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* find_first_zero_bit - find the first zero bit in a memory region
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* @addr: The address to start the search at
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* @addr: The address to start the search at
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@ -59,6 +60,7 @@ static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
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}
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}
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return x;
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return x;
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}
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}
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#endif
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#ifdef __KERNEL__
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#ifdef __KERNEL__
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@ -113,6 +113,40 @@ static inline unsigned fls_long(unsigned long l)
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}
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}
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#ifdef __KERNEL__
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#ifdef __KERNEL__
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#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
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extern unsigned long __find_first_bit(const unsigned long *addr,
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unsigned long size);
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/**
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* find_first_bit - find the first set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first set bit.
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*/
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static __always_inline unsigned long
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find_first_bit(const unsigned long *addr, unsigned long size)
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{
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return __find_first_bit(addr, size);
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}
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extern unsigned long __find_first_zero_bit(const unsigned long *addr,
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unsigned long size);
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/**
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* find_first_zero_bit - find the first cleared bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first cleared bit.
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*/
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static __always_inline unsigned long
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find_first_zero_bit(const unsigned long *addr, unsigned long size)
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{
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return __find_first_zero_bit(addr, size);
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}
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#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
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#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
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#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
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extern unsigned long __find_next_bit(const unsigned long *addr,
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extern unsigned long __find_next_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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unsigned long size, unsigned long offset);
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@ -29,6 +29,7 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
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lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
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lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
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lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
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lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
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lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o
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lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
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lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
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obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
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obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
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obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
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obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
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@ -16,6 +16,7 @@
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
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/*
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/*
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* Find the next set bit in a memory region.
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* Find the next set bit in a memory region.
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*/
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*/
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@ -102,6 +103,63 @@ found_middle:
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return result + ffz(tmp);
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return result + ffz(tmp);
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}
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}
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EXPORT_SYMBOL(__find_next_zero_bit);
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EXPORT_SYMBOL(__find_next_zero_bit);
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#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
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#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
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/*
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* Find the first set bit in a memory region.
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*/
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unsigned long __find_first_bit(const unsigned long *addr,
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unsigned long size)
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{
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const unsigned long *p = addr;
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unsigned long result = 0;
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unsigned long tmp;
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while (size & ~(BITS_PER_LONG-1)) {
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if ((tmp = *(p++)))
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goto found;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found:
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return result + __ffs(tmp);
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}
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EXPORT_SYMBOL(__find_first_bit);
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/*
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* Find the first cleared bit in a memory region.
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*/
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unsigned long __find_first_zero_bit(const unsigned long *addr,
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unsigned long size)
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{
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const unsigned long *p = addr;
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unsigned long result = 0;
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unsigned long tmp;
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while (size & ~(BITS_PER_LONG-1)) {
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if (~(tmp = *(p++)))
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goto found;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = (*p) | (~0UL << size);
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. */
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found:
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return result + ffz(tmp);
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}
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EXPORT_SYMBOL(__find_first_zero_bit);
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#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
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#ifdef __BIG_ENDIAN
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#ifdef __BIG_ENDIAN
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