diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/include/asm/bitops.h | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h new file mode 100644 index 000000000..2edf68475 --- /dev/null +++ b/arch/x86/include/asm/bitops.h @@ -0,0 +1,433 @@ +/* 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 */ |