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- /* SPDX-License-Identifier: GPL-2.0 */
- #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).
- */
- #define RLONG_ADDR(x) "m" (*(volatile long *) (x))
- #define WBYTE_ADDR(x) "+m" (*(volatile char *) (x))
- #define ADDR RLONG_ADDR(addr)
- /*
- * We do the locked ops that don't return the old value as
- * a mask operation on a byte.
- */
- #define CONST_MASK_ADDR(nr, addr) WBYTE_ADDR((void *)(addr) + ((nr)>>3))
- #define CONST_MASK(nr) (1 << ((nr) & 7))
- static __always_inline void
- arch_set_bit(long nr, volatile unsigned long *addr)
- {
- if (__builtin_constant_p(nr)) {
- asm volatile(LOCK_PREFIX "orb %b1,%0"
- : CONST_MASK_ADDR(nr, addr)
- : "iq" (CONST_MASK(nr))
- : "memory");
- } else {
- asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0"
- : : RLONG_ADDR(addr), "Ir" (nr) : "memory");
- }
- }
- static __always_inline void
- arch___set_bit(unsigned long nr, volatile unsigned long *addr)
- {
- asm volatile(__ASM_SIZE(bts) " %1,%0" : : ADDR, "Ir" (nr) : "memory");
- }
- static __always_inline void
- arch_clear_bit(long nr, volatile unsigned long *addr)
- {
- if (__builtin_constant_p(nr)) {
- asm volatile(LOCK_PREFIX "andb %b1,%0"
- : CONST_MASK_ADDR(nr, addr)
- : "iq" (~CONST_MASK(nr)));
- } else {
- asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0"
- : : RLONG_ADDR(addr), "Ir" (nr) : "memory");
- }
- }
- static __always_inline void
- arch_clear_bit_unlock(long nr, volatile unsigned long *addr)
- {
- barrier();
- arch_clear_bit(nr, addr);
- }
- static __always_inline void
- arch___clear_bit(unsigned long nr, volatile unsigned long *addr)
- {
- asm volatile(__ASM_SIZE(btr) " %1,%0" : : ADDR, "Ir" (nr) : "memory");
- }
- static __always_inline bool
- arch_clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
- {
- bool negative;
- asm volatile(LOCK_PREFIX "andb %2,%1"
- CC_SET(s)
- : CC_OUT(s) (negative), WBYTE_ADDR(addr)
- : "ir" ((char) ~(1 << nr)) : "memory");
- return negative;
- }
- #define arch_clear_bit_unlock_is_negative_byte \
- arch_clear_bit_unlock_is_negative_byte
- static __always_inline void
- arch___clear_bit_unlock(long nr, volatile unsigned long *addr)
- {
- arch___clear_bit(nr, addr);
- }
- static __always_inline void
- arch___change_bit(unsigned long nr, volatile unsigned long *addr)
- {
- asm volatile(__ASM_SIZE(btc) " %1,%0" : : ADDR, "Ir" (nr) : "memory");
- }
- static __always_inline void
- arch_change_bit(long nr, volatile unsigned long *addr)
- {
- if (__builtin_constant_p(nr)) {
- asm volatile(LOCK_PREFIX "xorb %b1,%0"
- : CONST_MASK_ADDR(nr, addr)
- : "iq" (CONST_MASK(nr)));
- } else {
- asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0"
- : : RLONG_ADDR(addr), "Ir" (nr) : "memory");
- }
- }
- static __always_inline bool
- arch_test_and_set_bit(long nr, volatile unsigned long *addr)
- {
- return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, c, "Ir", nr);
- }
- static __always_inline bool
- arch_test_and_set_bit_lock(long nr, volatile unsigned long *addr)
- {
- return arch_test_and_set_bit(nr, addr);
- }
- static __always_inline bool
- arch___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
- {
- bool oldbit;
- asm(__ASM_SIZE(bts) " %2,%1"
- CC_SET(c)
- : CC_OUT(c) (oldbit)
- : ADDR, "Ir" (nr) : "memory");
- return oldbit;
- }
- static __always_inline bool
- arch_test_and_clear_bit(long nr, volatile unsigned long *addr)
- {
- return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr), *addr, c, "Ir", nr);
- }
- /*
- * 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
- arch___test_and_clear_bit(unsigned 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) : "memory");
- return oldbit;
- }
- static __always_inline bool
- arch___test_and_change_bit(unsigned 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;
- }
- static __always_inline bool
- arch_test_and_change_bit(long nr, volatile unsigned long *addr)
- {
- return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr);
- }
- 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 constant_test_bit_acquire(long nr, const volatile unsigned long *addr)
- {
- bool oldbit;
- asm volatile("testb %2,%1"
- CC_SET(nz)
- : CC_OUT(nz) (oldbit)
- : "m" (((unsigned char *)addr)[nr >> 3]),
- "i" (1 << (nr & 7))
- :"memory");
- return oldbit;
- }
- 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) : "memory");
- return oldbit;
- }
- static __always_inline bool
- arch_test_bit(unsigned long nr, const volatile unsigned long *addr)
- {
- return __builtin_constant_p(nr) ? constant_test_bit(nr, addr) :
- variable_test_bit(nr, addr);
- }
- static __always_inline bool
- arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr)
- {
- return __builtin_constant_p(nr) ? constant_test_bit_acquire(nr, addr) :
- variable_test_bit(nr, addr);
- }
- static __always_inline unsigned long variable__ffs(unsigned long word)
- {
- asm("rep; bsf %1,%0"
- : "=r" (word)
- : "rm" (word));
- return word;
- }
- /**
- * __ffs - find first set bit in word
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
- #define __ffs(word) \
- (__builtin_constant_p(word) ? \
- (unsigned long)__builtin_ctzl(word) : \
- variable__ffs(word))
- static __always_inline unsigned long variable_ffz(unsigned long word)
- {
- asm("rep; bsf %1,%0"
- : "=r" (word)
- : "r" (~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.
- */
- #define ffz(word) \
- (__builtin_constant_p(word) ? \
- (unsigned long)__builtin_ctzl(~word) : \
- variable_ffz(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__
- static __always_inline int variable_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;
- }
- /**
- * 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.
- */
- #define ffs(x) (__builtin_constant_p(x) ? __builtin_ffs(x) : variable_ffs(x))
- /**
- * 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(unsigned 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/sched.h>
- #include <asm/arch_hweight.h>
- #include <asm-generic/bitops/const_hweight.h>
- #include <asm-generic/bitops/instrumented-atomic.h>
- #include <asm-generic/bitops/instrumented-non-atomic.h>
- #include <asm-generic/bitops/instrumented-lock.h>
- #include <asm-generic/bitops/le.h>
- #include <asm-generic/bitops/ext2-atomic-setbit.h>
- #endif /* __KERNEL__ */
- #endif /* _ASM_X86_BITOPS_H */
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