| /* 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 IS_IMMEDIATE(nr) (__builtin_constant_p(nr)) |
| #define CONST_MASK_ADDR(nr, addr) WBYTE_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" |
| : : RLONG_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" |
| : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); |
| } |
| } |
| |
| /* |
| * 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) : "memory"); |
| } |
| |
| static __always_inline bool 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; |
| } |
| |
| // Let everybody know we have it |
| #define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte |
| |
| /* |
| * __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. |
| */ |
| static __always_inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) |
| { |
| __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) : "memory"); |
| } |
| |
| /** |
| * 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" |
| : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); |
| } |
| } |
| |
| /** |
| * 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) |
| { |
| return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, c, "Ir", nr); |
| } |
| |
| /** |
| * 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) : "memory"); |
| 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) |
| { |
| return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr), *addr, c, "Ir", nr); |
| } |
| |
| /** |
| * __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) : "memory"); |
| 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) |
| { |
| 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 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; |
| } |
| |
| #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(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/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 */ |