/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* PowerPC atomic bit operations.
*
* Merged version by David Gibson <david@gibson.dropbear.id.au>.
* Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
* Reed, Pat McCarthy, Peter Bergner, Anton Blanchard. They
* originally took it from the ppc32 code.
*
* Within a word, bits are numbered LSB first. Lot's of places make
* this assumption by directly testing bits with (val & (1<<nr)).
* This can cause confusion for large (> 1 word) bitmaps on a
* big-endian system because, unlike little endian, the number of each
* bit depends on the word size.
*
* The bitop functions are defined to work on unsigned longs, so for a
* ppc64 system the bits end up numbered:
* |63..............0|127............64|191...........128|255...........192|
* and on ppc32:
* |31.....0|63....32|95....64|127...96|159..128|191..160|223..192|255..224|
*
* There are a few little-endian macros used mostly for filesystem
* bitmaps, these work on similar bit arrays layouts, but
* byte-oriented:
* |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
*
* The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
* number field needs to be reversed compared to the big-endian bit
* fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
*/
#ifndef _ASM_POWERPC_BITOPS_H
#define _ASM_POWERPC_BITOPS_H
#ifdef __KERNEL__
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
#include <linux/compiler.h>
#include <asm/asm-compat.h>
#include <asm/synch.h>
/* PPC bit number conversion */
#define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
#define PPC_BIT(bit) (1UL << PPC_BITLSHIFT(bit))
#define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
/* Put a PPC bit into a "normal" bit position */
#define PPC_BITEXTRACT(bits, ppc_bit, dst_bit) \
((((bits) >> PPC_BITLSHIFT(ppc_bit)) & 1) << (dst_bit))
#define PPC_BITLSHIFT32(be) (32 - 1 - (be))
#define PPC_BIT32(bit) (1UL << PPC_BITLSHIFT32(bit))
#define PPC_BITMASK32(bs, be) ((PPC_BIT32(bs) - PPC_BIT32(be))|PPC_BIT32(bs))
#define PPC_BITLSHIFT8(be) (8 - 1 - (be))
#define PPC_BIT8(bit) (1UL << PPC_BITLSHIFT8(bit))
#define PPC_BITMASK8(bs, be) ((PPC_BIT8(bs) - PPC_BIT8(be))|PPC_BIT8(bs))
#include <asm/barrier.h>
/* Macro for generating the ***_bits() functions */
#define DEFINE_BITOP(fn, op, prefix) \
static inline void fn(unsigned long mask, \
volatile unsigned long *_p) \
{ \
unsigned long old; \
unsigned long *p = (unsigned long *)_p; \
__asm__ __volatile__ ( \
prefix \
"1:" PPC_LLARX "%0,0,%3,0\n" \
#op "%I2 %0,%0,%2\n" \
PPC_STLCX "%0,0,%3\n" \
"bne- 1b\n" \
: "=&r" (old), "+m" (*p) \
: "rK" (mask), "r" (p) \
: "cc", "memory"); \
}
DEFINE_BITOP(set_bits, or, "")
DEFINE_BITOP(change_bits, xor, "")
static __always_inline bool is_rlwinm_mask_valid(unsigned long x)
{
if (!x)
return false;
if (x & 1)
x = ~x; // make the mask non-wrapping
x += x & -x; // adding the low set bit results in at most one bit set
return !(x & (x - 1));
}
#define DEFINE_CLROP(fn, prefix) \
static inline void fn(unsigned long mask, volatile unsigned long *_p) \
{ \
unsigned long old; \
unsigned long *p = (unsigned long *)_p; \
\
if (IS_ENABLED(CONFIG_PPC32) && \
__builtin_constant_p(mask) && is_rlwinm_mask_valid(~mask)) {\
asm volatile ( \
prefix \
"1:" "lwarx %0,0,%3\n" \
"rlwinm %0,%0,0,%2\n" \
"stwcx. %0,0,%3\n" \
"bne- 1b\n" \
: "=&r" (old), "+m" (*p) \
: "n" (~mask), "r" (p) \
: "cc", "memory"); \
} else { \
asm volatile ( \
prefix \
"1:" PPC_LLARX "%0,0,%3,0\n" \
"andc %0,%0,%2\n" \
PPC_STLCX "%0,0,%3\n" \
"bne- 1b\n" \
: "=&r" (old), "+m" (*p) \
: "r" (mask), "r" (p) \
: "cc", "memory"); \
} \
}
DEFINE_CLROP(clear_bits, "")
DEFINE_CLROP(clear_bits_unlock, PPC_RELEASE_BARRIER)
static inline void arch_set_bit(int nr, volatile unsigned long *addr)
{
set_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}
static inline void arch_clear_bit(int nr, volatile unsigned long *addr)
{
clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}
static inline void arch_clear_bit_unlock(int nr, volatile unsigned long *addr)
{
clear_bits_unlock(BIT_MASK(nr), addr + BIT_WORD(nr));
}
static inline void arch_change_bit(int nr, volatile unsigned long *addr)
{
change_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}
/* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output
* operands. */
#define DEFINE_TESTOP(fn, op, prefix, postfix, eh) \
static inline unsigned long fn( \
unsigned long mask, \
volatile unsigned long *_p) \
{ \
unsigned long old, t; \
unsigned long *p = (unsigned long *)_p; \
__asm__ __volatile__ ( \
prefix \
"1:" PPC_LLARX "%0,0,%3,%4\n" \
#op "%I2 %1,%0,%2\n" \
PPC_STLCX "%1,0,%3\n" \
"bne- 1b\n" \
postfix \
: "=&r" (old), "=&r" (t) \
: "rK" (mask), "r" (p), "n" (eh) \
: "cc", "memory"); \
return (old & mask); \
}
DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER,
PPC_ATOMIC_EXIT_BARRIER, 0)
DEFINE_TESTOP(test_and_set_bits_lock, or, "",
PPC_ACQUIRE_BARRIER, IS_ENABLED(CONFIG_PPC64))
DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER,
PPC_ATOMIC_EXIT_BARRIER, 0)
static inline unsigned long test_and_clear_bits(unsigned long mask, volatile unsigned long *_p)
{
unsigned long old, t;
unsigned long *p = (unsigned long *)_p;
if (IS_ENABLED(CONFIG_PPC32) &&
__builtin_constant_p(mask) && is_rlwinm_mask_valid(~mask)) {
asm volatile (
PPC_ATOMIC_ENTRY_BARRIER
"1:" "lwarx %0,0,%3\n"
"rlwinm %1,%0,0,%2\n"
"stwcx. %1,0,%3\n"
"bne- 1b\n"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (old), "=&r" (t)
: "n" (~mask), "r" (p)
: "cc", "memory");
} else {
asm volatile (
PPC_ATOMIC_ENTRY_BARRIER
"1:" PPC_LLARX "%0,0,%3,0\n"
"andc %1,%0,%2\n"
PPC_STLCX "%1,0,%3\n"
"bne- 1b\n"
PPC_ATOMIC_EXIT_BARRIER
: "=&r" (old), "=&r" (t)
: "r" (mask), "r" (p)
: "cc", "memory");
}
return (old & mask);
}
static inline int arch_test_and_set_bit(unsigned long nr,
volatile unsigned long *addr)
{
return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}
static inline int arch_test_and_set_bit_lock(unsigned long nr,
volatile unsigned long *addr)
{
return test_and_set_bits_lock(BIT_MASK(nr),
addr + BIT_WORD(nr)) != 0;
}
static inline int arch_test_and_clear_bit(unsigned long nr,
volatile unsigned long *addr)
{
return test_and_clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}
static inline int arch_test_and_change_bit(unsigned long nr,
volatile unsigned long *addr)
{
return test_and_change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}
#ifdef CONFIG_PPC64
static inline unsigned long
clear_bit_unlock_return_word(int nr, volatile unsigned long *addr)
{
unsigned long old, t;
unsigned long *p = (unsigned long *)addr + BIT_WORD(nr);
unsigned long mask = BIT_MASK(nr);
__asm__ __volatile__ (
PPC_RELEASE_BARRIER
"1:" PPC_LLARX "%0,0,%3,0\n"
"andc %1,%0,%2\n"
PPC_STLCX "%1,0,%3\n"
"bne- 1b\n"
: "=&r" (old), "=&r" (t)
: "r" (mask), "r" (p)
: "cc", "memory");
return old;
}
/*
* This is a special function for mm/filemap.c
* Bit 7 corresponds to PG_waiters.
*/
#define arch_clear_bit_unlock_is_negative_byte(nr, addr) \
(clear_bit_unlock_return_word(nr, addr) & BIT_MASK(7))
#endif /* CONFIG_PPC64 */
#include <asm-generic/bitops/non-atomic.h>
static inline void arch___clear_bit_unlock(int nr, volatile unsigned long *addr)
{
__asm__ __volatile__(PPC_RELEASE_BARRIER "" ::: "memory");
__clear_bit(nr, addr);
}
/*
* Return the zero-based bit position (LE, not IBM bit numbering) of
* the most significant 1-bit in a double word.
*/
#define __ilog2(x) ilog2(x)
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/builtin-__ffs.h>
#include <asm-generic/bitops/builtin-ffs.h>
/*
* fls: find last (most-significant) bit set.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
static __always_inline int fls(unsigned int x)
{
int lz;
if (__builtin_constant_p(x))
return x ? 32 - __builtin_clz(x) : 0;
asm("cntlzw %0,%1" : "=r" (lz) : "r" (x));
return 32 - lz;
}
#include <asm-generic/bitops/builtin-__fls.h>
/*
* 64-bit can do this using one cntlzd (count leading zeroes doubleword)
* instruction; for 32-bit we use the generic version, which does two
* 32-bit fls calls.
*/
#ifdef CONFIG_PPC64
static __always_inline int fls64(__u64 x)
{
int lz;
if (__builtin_constant_p(x))
return x ? 64 - __builtin_clzll(x) : 0;
asm("cntlzd %0,%1" : "=r" (lz) : "r" (x));
return 64 - lz;
}
#else
#include <asm-generic/bitops/fls64.h>
#endif
#ifdef CONFIG_PPC64
unsigned int __arch_hweight8(unsigned int w);
unsigned int __arch_hweight16(unsigned int w);
unsigned int __arch_hweight32(unsigned int w);
unsigned long __arch_hweight64(__u64 w);
#include <asm-generic/bitops/const_hweight.h>
#else
#include <asm-generic/bitops/hweight.h>
#endif
/* wrappers that deal with KASAN instrumentation */
#include <asm-generic/bitops/instrumented-atomic.h>
#include <asm-generic/bitops/instrumented-lock.h>
/* Little-endian versions */
#include <asm-generic/bitops/le.h>
/* Bitmap functions for the ext2 filesystem */
#include <asm-generic/bitops/ext2-atomic-setbit.h>
#include <asm-generic/bitops/sched.h>
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_BITOPS_H */