513 lines
14 KiB
C
513 lines
14 KiB
C
|
#ifndef _ASM_X86_BITOPS_H
|
||
|
#define _ASM_X86_BITOPS_H
|
||
|
|
||
|
/*
|
||
|
* Copyright 1992, Linus Torvalds.
|
||
|
*
|
||
|
* Note: inlines with more than a single statement should be marked
|
||
|
* __always_inline to avoid problems with older gcc's inlining heuristics.
|
||
|
*/
|
||
|
|
||
|
#ifndef _LINUX_BITOPS_H
|
||
|
#error only <linux/bitops.h> can be included directly
|
||
|
#endif
|
||
|
|
||
|
#include <linux/compiler.h>
|
||
|
#include <asm/alternative.h>
|
||
|
#include <asm/rmwcc.h>
|
||
|
#include <asm/barrier.h>
|
||
|
|
||
|
#if BITS_PER_LONG == 32
|
||
|
# define _BITOPS_LONG_SHIFT 5
|
||
|
#elif BITS_PER_LONG == 64
|
||
|
# define _BITOPS_LONG_SHIFT 6
|
||
|
#else
|
||
|
# error "Unexpected BITS_PER_LONG"
|
||
|
#endif
|
||
|
|
||
|
#define BIT_64(n) (U64_C(1) << (n))
|
||
|
|
||
|
/*
|
||
|
* These have to be done with inline assembly: that way the bit-setting
|
||
|
* is guaranteed to be atomic. All bit operations return 0 if the bit
|
||
|
* was cleared before the operation and != 0 if it was not.
|
||
|
*
|
||
|
* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
|
||
|
*/
|
||
|
|
||
|
#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1)
|
||
|
/* Technically wrong, but this avoids compilation errors on some gcc
|
||
|
versions. */
|
||
|
#define BITOP_ADDR(x) "=m" (*(volatile long *) (x))
|
||
|
#else
|
||
|
#define BITOP_ADDR(x) "+m" (*(volatile long *) (x))
|
||
|
#endif
|
||
|
|
||
|
#define ADDR BITOP_ADDR(addr)
|
||
|
|
||
|
/*
|
||
|
* We do the locked ops that don't return the old value as
|
||
|
* a mask operation on a byte.
|
||
|
*/
|
||
|
#define IS_IMMEDIATE(nr) (__builtin_constant_p(nr))
|
||
|
#define CONST_MASK_ADDR(nr, addr) BITOP_ADDR((void *)(addr) + ((nr)>>3))
|
||
|
#define CONST_MASK(nr) (1 << ((nr) & 7))
|
||
|
|
||
|
/**
|
||
|
* set_bit - Atomically set a bit in memory
|
||
|
* @nr: the bit to set
|
||
|
* @addr: the address to start counting from
|
||
|
*
|
||
|
* This function is atomic and may not be reordered. See __set_bit()
|
||
|
* if you do not require the atomic guarantees.
|
||
|
*
|
||
|
* Note: there are no guarantees that this function will not be reordered
|
||
|
* on non x86 architectures, so if you are writing portable code,
|
||
|
* make sure not to rely on its reordering guarantees.
|
||
|
*
|
||
|
* Note that @nr may be almost arbitrarily large; this function is not
|
||
|
* restricted to acting on a single-word quantity.
|
||
|
*/
|
||
|
static __always_inline void
|
||
|
set_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
if (IS_IMMEDIATE(nr)) {
|
||
|
asm volatile(LOCK_PREFIX "orb %1,%0"
|
||
|
: CONST_MASK_ADDR(nr, addr)
|
||
|
: "iq" ((u8)CONST_MASK(nr))
|
||
|
: "memory");
|
||
|
} else {
|
||
|
asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0"
|
||
|
: BITOP_ADDR(addr) : "Ir" (nr) : "memory");
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* __set_bit - Set a bit in memory
|
||
|
* @nr: the bit to set
|
||
|
* @addr: the address to start counting from
|
||
|
*
|
||
|
* Unlike set_bit(), this function is non-atomic and may be reordered.
|
||
|
* If it's called on the same region of memory simultaneously, the effect
|
||
|
* may be that only one operation succeeds.
|
||
|
*/
|
||
|
static __always_inline void __set_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
asm volatile(__ASM_SIZE(bts) " %1,%0" : ADDR : "Ir" (nr) : "memory");
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* clear_bit - Clears a bit in memory
|
||
|
* @nr: Bit to clear
|
||
|
* @addr: Address to start counting from
|
||
|
*
|
||
|
* clear_bit() is atomic and may not be reordered. However, it does
|
||
|
* not contain a memory barrier, so if it is used for locking purposes,
|
||
|
* you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
|
||
|
* in order to ensure changes are visible on other processors.
|
||
|
*/
|
||
|
static __always_inline void
|
||
|
clear_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
if (IS_IMMEDIATE(nr)) {
|
||
|
asm volatile(LOCK_PREFIX "andb %1,%0"
|
||
|
: CONST_MASK_ADDR(nr, addr)
|
||
|
: "iq" ((u8)~CONST_MASK(nr)));
|
||
|
} else {
|
||
|
asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0"
|
||
|
: BITOP_ADDR(addr)
|
||
|
: "Ir" (nr));
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* clear_bit_unlock - Clears a bit in memory
|
||
|
* @nr: Bit to clear
|
||
|
* @addr: Address to start counting from
|
||
|
*
|
||
|
* clear_bit() is atomic and implies release semantics before the memory
|
||
|
* operation. It can be used for an unlock.
|
||
|
*/
|
||
|
static __always_inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
barrier();
|
||
|
clear_bit(nr, addr);
|
||
|
}
|
||
|
|
||
|
static __always_inline void __clear_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
asm volatile(__ASM_SIZE(btr) " %1,%0" : ADDR : "Ir" (nr));
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* __clear_bit_unlock - Clears a bit in memory
|
||
|
* @nr: Bit to clear
|
||
|
* @addr: Address to start counting from
|
||
|
*
|
||
|
* __clear_bit() is non-atomic and implies release semantics before the memory
|
||
|
* operation. It can be used for an unlock if no other CPUs can concurrently
|
||
|
* modify other bits in the word.
|
||
|
*
|
||
|
* No memory barrier is required here, because x86 cannot reorder stores past
|
||
|
* older loads. Same principle as spin_unlock.
|
||
|
*/
|
||
|
static __always_inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
barrier();
|
||
|
__clear_bit(nr, addr);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* __change_bit - Toggle a bit in memory
|
||
|
* @nr: the bit to change
|
||
|
* @addr: the address to start counting from
|
||
|
*
|
||
|
* Unlike change_bit(), this function is non-atomic and may be reordered.
|
||
|
* If it's called on the same region of memory simultaneously, the effect
|
||
|
* may be that only one operation succeeds.
|
||
|
*/
|
||
|
static __always_inline void __change_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
asm volatile(__ASM_SIZE(btc) " %1,%0" : ADDR : "Ir" (nr));
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* change_bit - Toggle a bit in memory
|
||
|
* @nr: Bit to change
|
||
|
* @addr: Address to start counting from
|
||
|
*
|
||
|
* change_bit() is atomic and may not be reordered.
|
||
|
* Note that @nr may be almost arbitrarily large; this function is not
|
||
|
* restricted to acting on a single-word quantity.
|
||
|
*/
|
||
|
static __always_inline void change_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
if (IS_IMMEDIATE(nr)) {
|
||
|
asm volatile(LOCK_PREFIX "xorb %1,%0"
|
||
|
: CONST_MASK_ADDR(nr, addr)
|
||
|
: "iq" ((u8)CONST_MASK(nr)));
|
||
|
} else {
|
||
|
asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0"
|
||
|
: BITOP_ADDR(addr)
|
||
|
: "Ir" (nr));
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* test_and_set_bit - Set a bit and return its old value
|
||
|
* @nr: Bit to set
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This operation is atomic and cannot be reordered.
|
||
|
* It also implies a memory barrier.
|
||
|
*/
|
||
|
static __always_inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts),
|
||
|
*addr, "Ir", nr, "%0", c);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* test_and_set_bit_lock - Set a bit and return its old value for lock
|
||
|
* @nr: Bit to set
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This is the same as test_and_set_bit on x86.
|
||
|
*/
|
||
|
static __always_inline bool
|
||
|
test_and_set_bit_lock(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
return test_and_set_bit(nr, addr);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* __test_and_set_bit - Set a bit and return its old value
|
||
|
* @nr: Bit to set
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This operation is non-atomic and can be reordered.
|
||
|
* If two examples of this operation race, one can appear to succeed
|
||
|
* but actually fail. You must protect multiple accesses with a lock.
|
||
|
*/
|
||
|
static __always_inline bool __test_and_set_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
bool oldbit;
|
||
|
|
||
|
asm(__ASM_SIZE(bts) " %2,%1"
|
||
|
CC_SET(c)
|
||
|
: CC_OUT(c) (oldbit), ADDR
|
||
|
: "Ir" (nr));
|
||
|
return oldbit;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* test_and_clear_bit - Clear a bit and return its old value
|
||
|
* @nr: Bit to clear
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This operation is atomic and cannot be reordered.
|
||
|
* It also implies a memory barrier.
|
||
|
*/
|
||
|
static __always_inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr),
|
||
|
*addr, "Ir", nr, "%0", c);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* __test_and_clear_bit - Clear a bit and return its old value
|
||
|
* @nr: Bit to clear
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This operation is non-atomic and can be reordered.
|
||
|
* If two examples of this operation race, one can appear to succeed
|
||
|
* but actually fail. You must protect multiple accesses with a lock.
|
||
|
*
|
||
|
* Note: the operation is performed atomically with respect to
|
||
|
* the local CPU, but not other CPUs. Portable code should not
|
||
|
* rely on this behaviour.
|
||
|
* KVM relies on this behaviour on x86 for modifying memory that is also
|
||
|
* accessed from a hypervisor on the same CPU if running in a VM: don't change
|
||
|
* this without also updating arch/x86/kernel/kvm.c
|
||
|
*/
|
||
|
static __always_inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
bool oldbit;
|
||
|
|
||
|
asm volatile(__ASM_SIZE(btr) " %2,%1"
|
||
|
CC_SET(c)
|
||
|
: CC_OUT(c) (oldbit), ADDR
|
||
|
: "Ir" (nr));
|
||
|
return oldbit;
|
||
|
}
|
||
|
|
||
|
/* WARNING: non atomic and it can be reordered! */
|
||
|
static __always_inline bool __test_and_change_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
bool oldbit;
|
||
|
|
||
|
asm volatile(__ASM_SIZE(btc) " %2,%1"
|
||
|
CC_SET(c)
|
||
|
: CC_OUT(c) (oldbit), ADDR
|
||
|
: "Ir" (nr) : "memory");
|
||
|
|
||
|
return oldbit;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* test_and_change_bit - Change a bit and return its old value
|
||
|
* @nr: Bit to change
|
||
|
* @addr: Address to count from
|
||
|
*
|
||
|
* This operation is atomic and cannot be reordered.
|
||
|
* It also implies a memory barrier.
|
||
|
*/
|
||
|
static __always_inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
|
||
|
{
|
||
|
GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc),
|
||
|
*addr, "Ir", nr, "%0", c);
|
||
|
}
|
||
|
|
||
|
static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr)
|
||
|
{
|
||
|
return ((1UL << (nr & (BITS_PER_LONG-1))) &
|
||
|
(addr[nr >> _BITOPS_LONG_SHIFT])) != 0;
|
||
|
}
|
||
|
|
||
|
static __always_inline bool variable_test_bit(long nr, volatile const unsigned long *addr)
|
||
|
{
|
||
|
bool oldbit;
|
||
|
|
||
|
asm volatile(__ASM_SIZE(bt) " %2,%1"
|
||
|
CC_SET(c)
|
||
|
: CC_OUT(c) (oldbit)
|
||
|
: "m" (*(unsigned long *)addr), "Ir" (nr));
|
||
|
|
||
|
return oldbit;
|
||
|
}
|
||
|
|
||
|
#if 0 /* Fool kernel-doc since it doesn't do macros yet */
|
||
|
/**
|
||
|
* test_bit - Determine whether a bit is set
|
||
|
* @nr: bit number to test
|
||
|
* @addr: Address to start counting from
|
||
|
*/
|
||
|
static bool test_bit(int nr, const volatile unsigned long *addr);
|
||
|
#endif
|
||
|
|
||
|
#define test_bit(nr, addr) \
|
||
|
(__builtin_constant_p((nr)) \
|
||
|
? constant_test_bit((nr), (addr)) \
|
||
|
: variable_test_bit((nr), (addr)))
|
||
|
|
||
|
/**
|
||
|
* __ffs - find first set 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)
|
||
|
{
|
||
|
asm("rep; bsf %1,%0"
|
||
|
: "=r" (word)
|
||
|
: "rm" (word));
|
||
|
return word;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* ffz - find first zero bit in word
|
||
|
* @word: The word to search
|
||
|
*
|
||
|
* Undefined if no zero exists, so code should check against ~0UL first.
|
||
|
*/
|
||
|
static __always_inline unsigned long ffz(unsigned long word)
|
||
|
{
|
||
|
asm("rep; bsf %1,%0"
|
||
|
: "=r" (word)
|
||
|
: "r" (~word));
|
||
|
return word;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* __fls: find last set bit in word
|
||
|
* @word: The word to search
|
||
|
*
|
||
|
* Undefined if no set bit exists, so code should check against 0 first.
|
||
|
*/
|
||
|
static __always_inline unsigned long __fls(unsigned long word)
|
||
|
{
|
||
|
asm("bsr %1,%0"
|
||
|
: "=r" (word)
|
||
|
: "rm" (word));
|
||
|
return word;
|
||
|
}
|
||
|
|
||
|
#undef ADDR
|
||
|
|
||
|
#ifdef __KERNEL__
|
||
|
/**
|
||
|
* ffs - find first set bit in word
|
||
|
* @x: the word to search
|
||
|
*
|
||
|
* This is defined the same way as the libc and compiler builtin ffs
|
||
|
* routines, therefore differs in spirit from the other bitops.
|
||
|
*
|
||
|
* ffs(value) returns 0 if value is 0 or the position of the first
|
||
|
* set bit if value is nonzero. The first (least significant) bit
|
||
|
* is at position 1.
|
||
|
*/
|
||
|
static __always_inline int ffs(int x)
|
||
|
{
|
||
|
int r;
|
||
|
|
||
|
#ifdef CONFIG_X86_64
|
||
|
/*
|
||
|
* AMD64 says BSFL won't clobber the dest reg if x==0; Intel64 says the
|
||
|
* dest reg is undefined if x==0, but their CPU architect says its
|
||
|
* value is written to set it to the same as before, except that the
|
||
|
* top 32 bits will be cleared.
|
||
|
*
|
||
|
* We cannot do this on 32 bits because at the very least some
|
||
|
* 486 CPUs did not behave this way.
|
||
|
*/
|
||
|
asm("bsfl %1,%0"
|
||
|
: "=r" (r)
|
||
|
: "rm" (x), "0" (-1));
|
||
|
#elif defined(CONFIG_X86_CMOV)
|
||
|
asm("bsfl %1,%0\n\t"
|
||
|
"cmovzl %2,%0"
|
||
|
: "=&r" (r) : "rm" (x), "r" (-1));
|
||
|
#else
|
||
|
asm("bsfl %1,%0\n\t"
|
||
|
"jnz 1f\n\t"
|
||
|
"movl $-1,%0\n"
|
||
|
"1:" : "=r" (r) : "rm" (x));
|
||
|
#endif
|
||
|
return r + 1;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* fls - find last set bit in word
|
||
|
* @x: the word to search
|
||
|
*
|
||
|
* This is defined in a similar way as the libc and compiler builtin
|
||
|
* ffs, but returns the position of the most significant set bit.
|
||
|
*
|
||
|
* fls(value) returns 0 if value is 0 or the position of the last
|
||
|
* set bit if value is nonzero. The last (most significant) bit is
|
||
|
* at position 32.
|
||
|
*/
|
||
|
static __always_inline int fls(int x)
|
||
|
{
|
||
|
int r;
|
||
|
|
||
|
#ifdef CONFIG_X86_64
|
||
|
/*
|
||
|
* AMD64 says BSRL won't clobber the dest reg if x==0; Intel64 says the
|
||
|
* dest reg is undefined if x==0, but their CPU architect says its
|
||
|
* value is written to set it to the same as before, except that the
|
||
|
* top 32 bits will be cleared.
|
||
|
*
|
||
|
* We cannot do this on 32 bits because at the very least some
|
||
|
* 486 CPUs did not behave this way.
|
||
|
*/
|
||
|
asm("bsrl %1,%0"
|
||
|
: "=r" (r)
|
||
|
: "rm" (x), "0" (-1));
|
||
|
#elif defined(CONFIG_X86_CMOV)
|
||
|
asm("bsrl %1,%0\n\t"
|
||
|
"cmovzl %2,%0"
|
||
|
: "=&r" (r) : "rm" (x), "rm" (-1));
|
||
|
#else
|
||
|
asm("bsrl %1,%0\n\t"
|
||
|
"jnz 1f\n\t"
|
||
|
"movl $-1,%0\n"
|
||
|
"1:" : "=r" (r) : "rm" (x));
|
||
|
#endif
|
||
|
return r + 1;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* fls64 - find last set bit in a 64-bit word
|
||
|
* @x: the word to search
|
||
|
*
|
||
|
* This is defined in a similar way as the libc and compiler builtin
|
||
|
* ffsll, but returns the position of the most significant set bit.
|
||
|
*
|
||
|
* fls64(value) returns 0 if value is 0 or the position of the last
|
||
|
* set bit if value is nonzero. The last (most significant) bit is
|
||
|
* at position 64.
|
||
|
*/
|
||
|
#ifdef CONFIG_X86_64
|
||
|
static __always_inline int fls64(__u64 x)
|
||
|
{
|
||
|
int bitpos = -1;
|
||
|
/*
|
||
|
* AMD64 says BSRQ won't clobber the dest reg if x==0; Intel64 says the
|
||
|
* dest reg is undefined if x==0, but their CPU architect says its
|
||
|
* value is written to set it to the same as before.
|
||
|
*/
|
||
|
asm("bsrq %1,%q0"
|
||
|
: "+r" (bitpos)
|
||
|
: "rm" (x));
|
||
|
return bitpos + 1;
|
||
|
}
|
||
|
#else
|
||
|
#include <asm-generic/bitops/fls64.h>
|
||
|
#endif
|
||
|
|
||
|
#include <asm-generic/bitops/find.h>
|
||
|
|
||
|
#include <asm-generic/bitops/sched.h>
|
||
|
|
||
|
#include <asm/arch_hweight.h>
|
||
|
|
||
|
#include <asm-generic/bitops/const_hweight.h>
|
||
|
|
||
|
#include <asm-generic/bitops/le.h>
|
||
|
|
||
|
#include <asm-generic/bitops/ext2-atomic-setbit.h>
|
||
|
|
||
|
#endif /* __KERNEL__ */
|
||
|
#endif /* _ASM_X86_BITOPS_H */
|