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7c6eb0b85c
find_next_bit operates on a bit instead of byte positions/sizes. Signed-off-by: Michal Clapinski <mclapinski@google.com>
210 lines
6.5 KiB
C
210 lines
6.5 KiB
C
#ifndef __CR_BITOPS_H__
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#define __CR_BITOPS_H__
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/*
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* PowerPC atomic bit operations.
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*
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* Merged version by David Gibson <david@gibson.dropbear.id.au>.
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* Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
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* Reed, Pat McCarthy, Peter Bergner, Anton Blanchard. They
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* originally took it from the ppc32 code.
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*
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* Within a word, bits are numbered LSB first. Lot's of places make
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* this assumption by directly testing bits with (val & (1<<nr)).
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* This can cause confusion for large (> 1 word) bitmaps on a
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* big-endian system because, unlike little endian, the number of each
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* bit depends on the word size.
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*
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* The bitop functions are defined to work on unsigned longs, so for a
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* ppc64 system the bits end up numbered:
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* |63..............0|127............64|191...........128|255...........192|
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* and on ppc32:
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* |31.....0|63....32|95....64|127...96|159..128|191..160|223..192|255..224|
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*
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* There are a few little-endian macros used mostly for filesystem
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* bitmaps, these work on similar bit arrays layouts, but
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* byte-oriented:
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* |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
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*
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* The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
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* number field needs to be reversed compared to the big-endian bit
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* fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* --
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* Copied from the kernel file arch/powerpc/include/asm/bitops.h
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*/
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#include "common/compiler.h"
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#include "common/asm/bitsperlong.h"
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#define DIV_ROUND_UP(n, d) (((n) + (d)-1) / (d))
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#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_LONG)
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#define DECLARE_BITMAP(name, bits) unsigned long name[BITS_TO_LONGS(bits)]
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#define BITMAP_SIZE(name) (sizeof(name) * CHAR_BIT)
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#define __stringify_in_c(...) #__VA_ARGS__
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#define stringify_in_c(...) __stringify_in_c(__VA_ARGS__) " "
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#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
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#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
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/* PPC bit number conversion */
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#define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
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#define PPC_BIT(bit) (1UL << PPC_BITLSHIFT(bit))
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#define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
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#define PPC_INST_LDARX 0x7c0000a8
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#define ___PPC_RA(a) (((a)&0x1f) << 16)
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#define ___PPC_RB(b) (((b)&0x1f) << 11)
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#define ___PPC_RS(s) (((s)&0x1f) << 21)
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#define __PPC_EH(eh) (((eh)&0x1) << 0)
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#define ___PPC_RT(t) ___PPC_RS(t)
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#define PPC_LDARX(t, a, b, eh) \
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stringify_in_c(.long PPC_INST_LDARX | ___PPC_RT(t) | ___PPC_RA(a) | ___PPC_RB(b) | __PPC_EH(eh))
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#define PPC_LLARX(t, a, b, eh) PPC_LDARX(t, a, b, eh)
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/* clang-format off */
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/* Macro for generating the ***_bits() functions */
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#define DEFINE_BITOP(fn, op) \
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static __inline__ void fn(unsigned long mask, \
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volatile unsigned long *_p) \
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{ \
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unsigned long old; \
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unsigned long *p = (unsigned long *)_p; \
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__asm__ __volatile__ ( \
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"1: ldarx %0,0,%3\n" \
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stringify_in_c(op) "%0,%0,%2\n" \
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"stdcx. %0,0,%3\n" \
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"bne- 1b\n" \
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: "=&r" (old), "+m" (*p) \
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: "r" (mask), "r" (p) \
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: "cc", "memory"); \
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}
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/* clang-format on */
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DEFINE_BITOP(set_bits, or)
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DEFINE_BITOP(clear_bits, andc)
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DEFINE_BITOP(change_bits, xor)
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static __inline__ void set_bit(int nr, volatile unsigned long *addr)
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{
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set_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
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}
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static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
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{
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clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
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}
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static __inline__ void change_bit(int nr, volatile unsigned long *addr)
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{
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change_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
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}
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static inline int test_bit(int nr, const volatile unsigned long *addr)
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{
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return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG - 1)));
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}
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/* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output
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* operands. */
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/* clang-format off */
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#define DEFINE_TESTOP(fn, op, prefix, postfix, eh) \
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static __inline__ unsigned long fn( \
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unsigned long mask, \
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volatile unsigned long *_p) \
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{ \
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unsigned long old, t; \
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unsigned long *p = (unsigned long *)_p; \
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__asm__ __volatile__ ( \
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prefix \
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"1:" PPC_LLARX(%0,0,%3,eh) "\n" \
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stringify_in_c(op) "%1,%0,%2\n" \
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"stdcx. %1,0,%3\n" \
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"bne- 1b\n" \
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postfix \
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: "=&r" (old), "=&r" (t) \
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: "r" (mask), "r" (p) \
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: "cc", "memory"); \
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return (old & mask); \
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}
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/* clang-format on */
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DEFINE_TESTOP(test_and_set_bits, or, "\nLWSYNC\n", "\nsync\n", 0)
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static __inline__ int test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
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{
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return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
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}
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/*
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* Return the zero-based bit position (LE, not IBM bit numbering) of
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* the most significant 1-bit in a double word.
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*/
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static __inline__ __attribute__((const)) int __ilog2(unsigned long x)
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{
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int lz;
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asm("cntlzd %0,%1" : "=r"(lz) : "r"(x));
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return BITS_PER_LONG - 1 - lz;
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}
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static __inline__ unsigned long __ffs(unsigned long x)
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{
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return __ilog2(x & -x);
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}
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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/*
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* Find the next set bit in a memory region.
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*/
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static inline unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
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{
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const unsigned long *p = addr + BITOP_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset %= BITS_PER_LONG;
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG - 1)) {
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if ((tmp = *(p++)))
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goto found_middle;
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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;
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found_first:
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tmp &= (~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_middle:
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return result + __ffs(tmp);
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}
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#define for_each_bit(i, bitmask) \
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for (i = find_next_bit(bitmask, BITMAP_SIZE(bitmask), 0); i < BITMAP_SIZE(bitmask); \
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i = find_next_bit(bitmask, BITMAP_SIZE(bitmask), i + 1))
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#endif /* __CR_BITOPS_H__ */
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