diff options
Diffstat (limited to 'include/asm-generic/bitops/instrumented-non-atomic.h')
| -rw-r--r-- | include/asm-generic/bitops/instrumented-non-atomic.h | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/instrumented-non-atomic.h b/include/asm-generic/bitops/instrumented-non-atomic.h new file mode 100644 index 000000000..37363d570 --- /dev/null +++ b/include/asm-generic/bitops/instrumented-non-atomic.h @@ -0,0 +1,138 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * This file provides wrappers with sanitizer instrumentation for non-atomic + * bit operations. + * + * To use this functionality, an arch's bitops.h file needs to define each of + * the below bit operations with an arch_ prefix (e.g. arch_set_bit(), + * arch___set_bit(), etc.). + */ +#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H +#define _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H + +#include <linux/instrumented.h> + +/** + * __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. If it is called on the same + * region of memory concurrently, the effect may be that only one operation + * succeeds. + */ +static inline void __set_bit(long nr, volatile unsigned long *addr) +{ + instrument_write(addr + BIT_WORD(nr), sizeof(long)); + arch___set_bit(nr, addr); +} + +/** + * __clear_bit - Clears a bit in memory + * @nr: the bit to clear + * @addr: the address to start counting from + * + * Unlike clear_bit(), this function is non-atomic. If it is called on the same + * region of memory concurrently, the effect may be that only one operation + * succeeds. + */ +static inline void __clear_bit(long nr, volatile unsigned long *addr) +{ + instrument_write(addr + BIT_WORD(nr), sizeof(long)); + arch___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. If it is called on the same + * region of memory concurrently, the effect may be that only one operation + * succeeds. + */ +static inline void __change_bit(long nr, volatile unsigned long *addr) +{ + instrument_write(addr + BIT_WORD(nr), sizeof(long)); + arch___change_bit(nr, addr); +} + +static inline void __instrument_read_write_bitop(long nr, volatile unsigned long *addr) +{ + if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC)) { + /* + * We treat non-atomic read-write bitops a little more special. + * Given the operations here only modify a single bit, assuming + * non-atomicity of the writer is sufficient may be reasonable + * for certain usage (and follows the permissible nature of the + * assume-plain-writes-atomic rule): + * 1. report read-modify-write races -> check read; + * 2. do not report races with marked readers, but do report + * races with unmarked readers -> check "atomic" write. + */ + kcsan_check_read(addr + BIT_WORD(nr), sizeof(long)); + /* + * Use generic write instrumentation, in case other sanitizers + * or tools are enabled alongside KCSAN. + */ + instrument_write(addr + BIT_WORD(nr), sizeof(long)); + } else { + instrument_read_write(addr + BIT_WORD(nr), sizeof(long)); + } +} + +/** + * __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. If two instances of this operation race, one + * can appear to succeed but actually fail. + */ +static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) +{ + __instrument_read_write_bitop(nr, addr); + return arch___test_and_set_bit(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 is non-atomic. If two instances of this operation race, one + * can appear to succeed but actually fail. + */ +static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) +{ + __instrument_read_write_bitop(nr, addr); + return arch___test_and_clear_bit(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 non-atomic. If two instances of this operation race, one + * can appear to succeed but actually fail. + */ +static inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) +{ + __instrument_read_write_bitop(nr, addr); + return arch___test_and_change_bit(nr, addr); +} + +/** + * test_bit - Determine whether a bit is set + * @nr: bit number to test + * @addr: Address to start counting from + */ +static inline bool test_bit(long nr, const volatile unsigned long *addr) +{ + instrument_atomic_read(addr + BIT_WORD(nr), sizeof(long)); + return arch_test_bit(nr, addr); +} + +#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */ |