diff options
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 134 |
1 files changed, 2 insertions, 132 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 204e76856435..59f7194fdf08 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -230,28 +230,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__) #endif -/* - * Prevent the compiler from merging or refetching reads or writes. The - * compiler is also forbidden from reordering successive instances of - * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some - * particular ordering. One way to make the compiler aware of ordering is to - * put the two invocations of READ_ONCE or WRITE_ONCE in different C - * statements. - * - * These two macros will also work on aggregate data types like structs or - * unions. - * - * Their two major use cases are: (1) Mediating communication between - * process-level code and irq/NMI handlers, all running on the same CPU, - * and (2) Ensuring that the compiler does not fold, spindle, or otherwise - * mutilate accesses that either do not require ordering or that interact - * with an explicit memory barrier or atomic instruction that provides the - * required ordering. - */ -#include <asm/barrier.h> -#include <linux/kasan-checks.h> -#include <linux/kcsan-checks.h> - /** * data_race - mark an expression as containing intentional data races * @@ -272,65 +250,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, __v; \ }) -/* - * Use __READ_ONCE() instead of READ_ONCE() if you do not require any - * atomicity or dependency ordering guarantees. Note that this may result - * in tears! - */ -#define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x)) - -#define __READ_ONCE_SCALAR(x) \ -({ \ - __unqual_scalar_typeof(x) __x = __READ_ONCE(x); \ - smp_read_barrier_depends(); \ - (typeof(x))__x; \ -}) - -#define READ_ONCE(x) \ -({ \ - compiletime_assert_rwonce_type(x); \ - __READ_ONCE_SCALAR(x); \ -}) - -#define __WRITE_ONCE(x, val) \ -do { \ - *(volatile typeof(x) *)&(x) = (val); \ -} while (0) - -#define WRITE_ONCE(x, val) \ -do { \ - compiletime_assert_rwonce_type(x); \ - __WRITE_ONCE(x, val); \ -} while (0) - -static __no_sanitize_or_inline -unsigned long __read_once_word_nocheck(const void *addr) -{ - return __READ_ONCE(*(unsigned long *)addr); -} - -/* - * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need to load a - * word from memory atomically but without telling KASAN/KCSAN. This is - * usually used by unwinding code when walking the stack of a running process. - */ -#define READ_ONCE_NOCHECK(x) \ -({ \ - unsigned long __x; \ - compiletime_assert(sizeof(x) == sizeof(__x), \ - "Unsupported access size for READ_ONCE_NOCHECK()."); \ - __x = __read_once_word_nocheck(&(x)); \ - smp_read_barrier_depends(); \ - (typeof(x))__x; \ -}) - -static __no_kasan_or_inline -unsigned long read_word_at_a_time(const void *addr) -{ - kasan_check_read(addr, 1); - return *(unsigned long *)addr; -} - #endif /* __KERNEL__ */ /* @@ -354,57 +273,6 @@ static inline void *offset_to_ptr(const int *off) #endif /* __ASSEMBLY__ */ -/* Compile time object size, -1 for unknown */ -#ifndef __compiletime_object_size -# define __compiletime_object_size(obj) -1 -#endif -#ifndef __compiletime_warning -# define __compiletime_warning(message) -#endif -#ifndef __compiletime_error -# define __compiletime_error(message) -#endif - -#ifdef __OPTIMIZE__ -# define __compiletime_assert(condition, msg, prefix, suffix) \ - do { \ - extern void prefix ## suffix(void) __compiletime_error(msg); \ - if (!(condition)) \ - prefix ## suffix(); \ - } while (0) -#else -# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0) -#endif - -#define _compiletime_assert(condition, msg, prefix, suffix) \ - __compiletime_assert(condition, msg, prefix, suffix) - -/** - * compiletime_assert - break build and emit msg if condition is false - * @condition: a compile-time constant condition to check - * @msg: a message to emit if condition is false - * - * In tradition of POSIX assert, this macro will break the build if the - * supplied condition is *false*, emitting the supplied error message if the - * compiler has support to do so. - */ -#define compiletime_assert(condition, msg) \ - _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) - -#define compiletime_assert_atomic_type(t) \ - compiletime_assert(__native_word(t), \ - "Need native word sized stores/loads for atomicity.") - -/* - * Yes, this permits 64-bit accesses on 32-bit architectures. These will - * actually be atomic in some cases (namely Armv7 + LPAE), but for others we - * rely on the access being split into 2x32-bit accesses for a 32-bit quantity - * (e.g. a virtual address) and a strong prevailing wind. - */ -#define compiletime_assert_rwonce_type(t) \ - compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \ - "Unsupported access size for {READ,WRITE}_ONCE().") - /* &a[0] degrades to a pointer: a different type from an array */ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) @@ -414,4 +282,6 @@ static inline void *offset_to_ptr(const int *off) */ #define prevent_tail_call_optimization() mb() +#include <asm/rwonce.h> + #endif /* __LINUX_COMPILER_H */ |