diff options
Diffstat (limited to 'include/linux/kernel.h')
| -rw-r--r-- | include/linux/kernel.h | 79 |
1 files changed, 47 insertions, 32 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3cbf3cfff4f0..6a1eb0b0aad9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -439,7 +439,8 @@ extern long simple_strtol(const char *,char **,unsigned int); extern unsigned long long simple_strtoull(const char *,char **,unsigned int); extern long long simple_strtoll(const char *,char **,unsigned int); -extern int num_to_str(char *buf, int size, unsigned long long num); +extern int num_to_str(char *buf, int size, + unsigned long long num, unsigned int width); /* lib/printf utilities */ @@ -543,6 +544,7 @@ extern enum system_states { SYSTEM_RESTART, } system_state; +/* This cannot be an enum because some may be used in assembly source. */ #define TAINT_PROPRIETARY_MODULE 0 #define TAINT_FORCED_MODULE 1 #define TAINT_CPU_OUT_OF_SPEC 2 @@ -560,7 +562,8 @@ extern enum system_states { #define TAINT_SOFTLOCKUP 14 #define TAINT_LIVEPATCH 15 #define TAINT_AUX 16 -#define TAINT_FLAGS_COUNT 17 +#define TAINT_RANDSTRUCT 17 +#define TAINT_FLAGS_COUNT 18 struct taint_flag { char c_true; /* character printed when tainted */ @@ -792,41 +795,59 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } #endif /* CONFIG_TRACING */ /* - * min()/max()/clamp() macros that also do - * strict type-checking.. See the - * "unnecessary" pointer comparison. + * min()/max()/clamp() macros must accomplish three things: + * + * - avoid multiple evaluations of the arguments (so side-effects like + * "x++" happen only once) when non-constant. + * - perform strict type-checking (to generate warnings instead of + * nasty runtime surprises). See the "unnecessary" pointer comparison + * in __typecheck(). + * - retain result as a constant expressions when called with only + * constant expressions (to avoid tripping VLA warnings in stack + * allocation usage). + */ +#define __typecheck(x, y) \ + (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) + +/* + * This returns a constant expression while determining if an argument is + * a constant expression, most importantly without evaluating the argument. + * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de> */ -#define __min(t1, t2, min1, min2, x, y) ({ \ - t1 min1 = (x); \ - t2 min2 = (y); \ - (void) (&min1 == &min2); \ - min1 < min2 ? min1 : min2; }) +#define __is_constexpr(x) \ + (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) + +#define __no_side_effects(x, y) \ + (__is_constexpr(x) && __is_constexpr(y)) + +#define __safe_cmp(x, y) \ + (__typecheck(x, y) && __no_side_effects(x, y)) + +#define __cmp(x, y, op) ((x) op (y) ? (x) : (y)) + +#define __cmp_once(x, y, unique_x, unique_y, op) ({ \ + typeof(x) unique_x = (x); \ + typeof(y) unique_y = (y); \ + __cmp(unique_x, unique_y, op); }) + +#define __careful_cmp(x, y, op) \ + __builtin_choose_expr(__safe_cmp(x, y), \ + __cmp(x, y, op), \ + __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op)) /** * min - return minimum of two values of the same or compatible types * @x: first value * @y: second value */ -#define min(x, y) \ - __min(typeof(x), typeof(y), \ - __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ - x, y) - -#define __max(t1, t2, max1, max2, x, y) ({ \ - t1 max1 = (x); \ - t2 max2 = (y); \ - (void) (&max1 == &max2); \ - max1 > max2 ? max1 : max2; }) +#define min(x, y) __careful_cmp(x, y, <) /** * max - return maximum of two values of the same or compatible types * @x: first value * @y: second value */ -#define max(x, y) \ - __max(typeof(x), typeof(y), \ - __UNIQUE_ID(max1_), __UNIQUE_ID(max2_), \ - x, y) +#define max(x, y) __careful_cmp(x, y, >) /** * min3 - return minimum of three values @@ -878,10 +899,7 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } * @x: first value * @y: second value */ -#define min_t(type, x, y) \ - __min(type, type, \ - __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ - x, y) +#define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) /** * max_t - return maximum of two values, using the specified type @@ -889,10 +907,7 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } * @x: first value * @y: second value */ -#define max_t(type, x, y) \ - __max(type, type, \ - __UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \ - x, y) +#define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >) /** * clamp_t - return a value clamped to a given range using a given type |