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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 Regents of the University of California
*/
#ifndef _ASM_RISCV_BITOPS_H
#define _ASM_RISCV_BITOPS_H
#ifndef _LINUX_BITOPS_H
#error "Only <linux/bitops.h> can be included directly"
#endif /* _LINUX_BITOPS_H */
#include <linux/compiler.h>
#include <linux/irqflags.h>
#include <asm/barrier.h>
#include <asm/bitsperlong.h>
#if !defined(CONFIG_RISCV_ISA_ZBB) || defined(NO_ALTERNATIVE)
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/ffs.h>
#include <asm-generic/bitops/fls.h>
#else
#include <asm/alternative-macros.h>
#include <asm/hwcap.h>
#if (BITS_PER_LONG == 64)
#define CTZW "ctzw "
#define CLZW "clzw "
#elif (BITS_PER_LONG == 32)
#define CTZW "ctz "
#define CLZW "clz "
#else
#error "Unexpected BITS_PER_LONG"
#endif
static __always_inline unsigned long variable__ffs(unsigned long word)
{
int num;
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
asm volatile (".option push\n"
".option arch,+zbb\n"
"ctz %0, %1\n"
".option pop\n"
: "=r" (word) : "r" (word) :);
return word;
legacy:
num = 0;
#if BITS_PER_LONG == 64
if ((word & 0xffffffff) == 0) {
num += 32;
word >>= 32;
}
#endif
if ((word & 0xffff) == 0) {
num += 16;
word >>= 16;
}
if ((word & 0xff) == 0) {
num += 8;
word >>= 8;
}
if ((word & 0xf) == 0) {
num += 4;
word >>= 4;
}
if ((word & 0x3) == 0) {
num += 2;
word >>= 2;
}
if ((word & 0x1) == 0)
num += 1;
return num;
}
/**
* __ffs - find first set bit in a long word
* @word: The word to search
*
* Undefined if no set 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__fls(unsigned long word)
{
int num;
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
asm volatile (".option push\n"
".option arch,+zbb\n"
"clz %0, %1\n"
".option pop\n"
: "=r" (word) : "r" (word) :);
return BITS_PER_LONG - 1 - word;
legacy:
num = BITS_PER_LONG - 1;
#if BITS_PER_LONG == 64
if (!(word & (~0ul << 32))) {
num -= 32;
word <<= 32;
}
#endif
if (!(word & (~0ul << (BITS_PER_LONG - 16)))) {
num -= 16;
word <<= 16;
}
if (!(word & (~0ul << (BITS_PER_LONG - 8)))) {
num -= 8;
word <<= 8;
}
if (!(word & (~0ul << (BITS_PER_LONG - 4)))) {
num -= 4;
word <<= 4;
}
if (!(word & (~0ul << (BITS_PER_LONG - 2)))) {
num -= 2;
word <<= 2;
}
if (!(word & (~0ul << (BITS_PER_LONG - 1))))
num -= 1;
return num;
}
/**
* __fls - find last set bit in a long word
* @word: the word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
#define __fls(word) \
(__builtin_constant_p(word) ? \
(unsigned long)(BITS_PER_LONG - 1 - __builtin_clzl(word)) : \
variable__fls(word))
static __always_inline int variable_ffs(int x)
{
int r;
if (!x)
return 0;
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
asm volatile (".option push\n"
".option arch,+zbb\n"
CTZW "%0, %1\n"
".option pop\n"
: "=r" (r) : "r" (x) :);
return r + 1;
legacy:
r = 1;
if (!(x & 0xffff)) {
x >>= 16;
r += 16;
}
if (!(x & 0xff)) {
x >>= 8;
r += 8;
}
if (!(x & 0xf)) {
x >>= 4;
r += 4;
}
if (!(x & 3)) {
x >>= 2;
r += 2;
}
if (!(x & 1)) {
x >>= 1;
r += 1;
}
return r;
}
/**
* ffs - find first set bit in a word
* @x: the word to search
*
* This is defined the same way as the libc and compiler builtin ffs routines.
*
* 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))
static __always_inline int variable_fls(unsigned int x)
{
int r;
if (!x)
return 0;
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
asm volatile (".option push\n"
".option arch,+zbb\n"
CLZW "%0, %1\n"
".option pop\n"
: "=r" (r) : "r" (x) :);
return 32 - r;
legacy:
r = 32;
if (!(x & 0xffff0000u)) {
x <<= 16;
r -= 16;
}
if (!(x & 0xff000000u)) {
x <<= 8;
r -= 8;
}
if (!(x & 0xf0000000u)) {
x <<= 4;
r -= 4;
}
if (!(x & 0xc0000000u)) {
x <<= 2;
r -= 2;
}
if (!(x & 0x80000000u)) {
x <<= 1;
r -= 1;
}
return r;
}
/**
* fls - find last set bit in a word
* @x: the word to search
*
* This is defined in a similar way as 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.
*/
#define fls(x) \
({ \
typeof(x) x_ = (x); \
__builtin_constant_p(x_) ? \
(int)((x_ != 0) ? (32 - __builtin_clz(x_)) : 0) \
: \
variable_fls(x_); \
})
#endif /* !defined(CONFIG_RISCV_ISA_ZBB) || defined(NO_ALTERNATIVE) */
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/sched.h>
#include <asm/arch_hweight.h>
#include <asm-generic/bitops/const_hweight.h>
#if (BITS_PER_LONG == 64)
#define __AMO(op) "amo" #op ".d"
#elif (BITS_PER_LONG == 32)
#define __AMO(op) "amo" #op ".w"
#else
#error "Unexpected BITS_PER_LONG"
#endif
#define __test_and_op_bit_ord(op, mod, nr, addr, ord) \
({ \
unsigned long __res, __mask; \
__mask = BIT_MASK(nr); \
__asm__ __volatile__ ( \
__AMO(op) #ord " %0, %2, %1" \
: "=r" (__res), "+A" (addr[BIT_WORD(nr)]) \
: "r" (mod(__mask)) \
: "memory"); \
((__res & __mask) != 0); \
})
#define __op_bit_ord(op, mod, nr, addr, ord) \
__asm__ __volatile__ ( \
__AMO(op) #ord " zero, %1, %0" \
: "+A" (addr[BIT_WORD(nr)]) \
: "r" (mod(BIT_MASK(nr))) \
: "memory");
#define __test_and_op_bit(op, mod, nr, addr) \
__test_and_op_bit_ord(op, mod, nr, addr, .aqrl)
#define __op_bit(op, mod, nr, addr) \
__op_bit_ord(op, mod, nr, addr, )
/* Bitmask modifiers */
#define __NOP(x) (x)
#define __NOT(x) (~(x))
/**
* test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation may be reordered on other architectures than x86.
*/
static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(or, __NOP, nr, addr);
}
/**
* test_and_clear_bit - Clear a bit and return its old value
* @nr: Bit to clear
* @addr: Address to count from
*
* This operation can be reordered on other architectures other than x86.
*/
static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(and, __NOT, nr, addr);
}
/**
* 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 inline int test_and_change_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(xor, __NOP, nr, addr);
}
/**
* set_bit - Atomically set a bit in memory
* @nr: the bit to set
* @addr: the address to start counting from
*
* 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 inline void set_bit(int nr, volatile unsigned long *addr)
{
__op_bit(or, __NOP, nr, addr);
}
/**
* clear_bit - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
* 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.
*/
static inline void clear_bit(int nr, volatile unsigned long *addr)
{
__op_bit(and, __NOT, nr, addr);
}
/**
* change_bit - Toggle a bit in memory
* @nr: Bit to change
* @addr: Address to start counting from
*
* change_bit() may be reordered on other architectures than x86.
* Note that @nr may be almost arbitrarily large; this function is not
* restricted to acting on a single-word quantity.
*/
static inline void change_bit(int nr, volatile unsigned long *addr)
{
__op_bit(xor, __NOP, nr, addr);
}
/**
* 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 operation is atomic and provides acquire barrier semantics.
* It can be used to implement bit locks.
*/
static inline int test_and_set_bit_lock(
unsigned long nr, volatile unsigned long *addr)
{
return __test_and_op_bit_ord(or, __NOP, nr, addr, .aq);
}
/**
* clear_bit_unlock - Clear a bit in memory, for unlock
* @nr: the bit to set
* @addr: the address to start counting from
*
* This operation is atomic and provides release barrier semantics.
*/
static inline void clear_bit_unlock(
unsigned long nr, volatile unsigned long *addr)
{
__op_bit_ord(and, __NOT, nr, addr, .rl);
}
/**
* __clear_bit_unlock - Clear a bit in memory, for unlock
* @nr: the bit to set
* @addr: the address to start counting from
*
* This operation is like clear_bit_unlock, however it is not atomic.
* It does provide release barrier semantics so it can be used to unlock
* a bit lock, however it would only be used if no other CPU can modify
* any bits in the memory until the lock is released (a good example is
* if the bit lock itself protects access to the other bits in the word).
*
* On RISC-V systems there seems to be no benefit to taking advantage of the
* non-atomic property here: it's a lot more instructions and we still have to
* provide release semantics anyway.
*/
static inline void __clear_bit_unlock(
unsigned long nr, volatile unsigned long *addr)
{
clear_bit_unlock(nr, addr);
}
static inline bool xor_unlock_is_negative_byte(unsigned long mask,
volatile unsigned long *addr)
{
unsigned long res;
__asm__ __volatile__ (
__AMO(xor) ".rl %0, %2, %1"
: "=r" (res), "+A" (*addr)
: "r" (__NOP(mask))
: "memory");
return (res & BIT(7)) != 0;
}
#undef __test_and_op_bit
#undef __op_bit
#undef __NOP
#undef __NOT
#undef __AMO
#include <asm-generic/bitops/non-atomic.h>
#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic.h>
#endif /* _ASM_RISCV_BITOPS_H */
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