linux-stable/include/asm-generic/bitops/non-atomic.h
Linus Torvalds 4cdc4cc2ad asm-generic changes for 5.15
The main content for 5.15 is a series that cleans up the handling of
 strncpy_from_user() and strnlen_user(), removing a lot of slightly
 incorrect versions of these in favor of the lib/strn*.c helpers
 that implement these correctly and more efficiently.
 
 The only architectures that retain a private version now are
 mips, ia64, um and parisc. I had offered to convert those at all,
 but Thomas Bogendoerfer wanted to keep the mips version for the
 moment until he had a chance to do regression testing.
 
 The branch also contains two patches for bitops and for ffs().
 
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "The main content for 5.15 is a series that cleans up the handling of
  strncpy_from_user() and strnlen_user(), removing a lot of slightly
  incorrect versions of these in favor of the lib/strn*.c helpers that
  implement these correctly and more efficiently.

  The only architectures that retain a private version now are mips,
  ia64, um and parisc. I had offered to convert those at all, but Thomas
  Bogendoerfer wanted to keep the mips version for the moment until he
  had a chance to do regression testing.

  The branch also contains two patches for bitops and for ffs()"

* tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  bitops/non-atomic: make @nr unsigned to avoid any DIV
  asm-generic: ffs: Drop bogus reference to ffz location
  asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols
  asm-generic: remove extra strn{cpy_from,len}_user declarations
  asm-generic: uaccess: remove inline strncpy_from_user/strnlen_user
  s390: use generic strncpy/strnlen from_user
  microblaze: use generic strncpy/strnlen from_user
  csky: use generic strncpy/strnlen from_user
  arc: use generic strncpy/strnlen from_user
  hexagon: use generic strncpy/strnlen from_user
  h8300: remove stale strncpy_from_user
  asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_user
2021-09-01 15:13:02 -07:00

122 lines
3.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
#include <asm/types.h>
/**
* arch___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
arch___set_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p |= mask;
}
#define __set_bit arch___set_bit
static __always_inline void
arch___clear_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p &= ~mask;
}
#define __clear_bit arch___clear_bit
/**
* arch___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 arch___change_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p ^= mask;
}
#define __change_bit arch___change_bit
/**
* arch___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 int
arch___test_and_set_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old | mask;
return (old & mask) != 0;
}
#define __test_and_set_bit arch___test_and_set_bit
/**
* arch___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.
*/
static __always_inline int
arch___test_and_clear_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old & ~mask;
return (old & mask) != 0;
}
#define __test_and_clear_bit arch___test_and_clear_bit
/* WARNING: non atomic and it can be reordered! */
static __always_inline int
arch___test_and_change_bit(unsigned int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old ^ mask;
return (old & mask) != 0;
}
#define __test_and_change_bit arch___test_and_change_bit
/**
* arch_test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*/
static __always_inline int
arch_test_bit(unsigned int nr, const volatile unsigned long *addr)
{
return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}
#define test_bit arch_test_bit
#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */