| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _LINUX_JIFFIES_H |
| 3 | #define _LINUX_JIFFIES_H |
| 4 | |
| 5 | #include <linux/cache.h> |
| 6 | #include <linux/limits.h> |
| 7 | #include <linux/math64.h> |
| 8 | #include <linux/minmax.h> |
| 9 | #include <linux/types.h> |
| 10 | #include <linux/time.h> |
| 11 | #include <linux/timex.h> |
| 12 | #include <vdso/jiffies.h> |
| 13 | #include <asm/param.h> /* for HZ */ |
| 14 | #include <generated/timeconst.h> |
| 15 | |
| 16 | /* |
| 17 | * The following defines establish the engineering parameters of the PLL |
| 18 | * model. The HZ variable establishes the timer interrupt frequency, 100 Hz |
| 19 | * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the |
| 20 | * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the |
| 21 | * nearest power of two in order to avoid hardware multiply operations. |
| 22 | */ |
| 23 | #if HZ >= 12 && HZ < 24 |
| 24 | # define SHIFT_HZ 4 |
| 25 | #elif HZ >= 24 && HZ < 48 |
| 26 | # define SHIFT_HZ 5 |
| 27 | #elif HZ >= 48 && HZ < 96 |
| 28 | # define SHIFT_HZ 6 |
| 29 | #elif HZ >= 96 && HZ < 192 |
| 30 | # define SHIFT_HZ 7 |
| 31 | #elif HZ >= 192 && HZ < 384 |
| 32 | # define SHIFT_HZ 8 |
| 33 | #elif HZ >= 384 && HZ < 768 |
| 34 | # define SHIFT_HZ 9 |
| 35 | #elif HZ >= 768 && HZ < 1536 |
| 36 | # define SHIFT_HZ 10 |
| 37 | #elif HZ >= 1536 && HZ < 3072 |
| 38 | # define SHIFT_HZ 11 |
| 39 | #elif HZ >= 3072 && HZ < 6144 |
| 40 | # define SHIFT_HZ 12 |
| 41 | #elif HZ >= 6144 && HZ < 12288 |
| 42 | # define SHIFT_HZ 13 |
| 43 | #else |
| 44 | # error Invalid value of HZ. |
| 45 | #endif |
| 46 | |
| 47 | /* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can |
| 48 | * improve accuracy by shifting LSH bits, hence calculating: |
| 49 | * (NOM << LSH) / DEN |
| 50 | * This however means trouble for large NOM, because (NOM << LSH) may no |
| 51 | * longer fit in 32 bits. The following way of calculating this gives us |
| 52 | * some slack, under the following conditions: |
| 53 | * - (NOM / DEN) fits in (32 - LSH) bits. |
| 54 | * - (NOM % DEN) fits in (32 - LSH) bits. |
| 55 | */ |
| 56 | #define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \ |
| 57 | + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN)) |
| 58 | |
| 59 | /* LATCH is used in the interval timer and ftape setup. */ |
| 60 | #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ |
| 61 | |
| 62 | extern int register_refined_jiffies(long clock_tick_rate); |
| 63 | |
| 64 | /* TICK_USEC is the time between ticks in usec assuming SHIFTED_HZ */ |
| 65 | #define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ) |
| 66 | |
| 67 | /* USER_TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ |
| 68 | #define USER_TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) |
| 69 | |
| 70 | #ifndef __jiffy_arch_data |
| 71 | #define __jiffy_arch_data |
| 72 | #endif |
| 73 | |
| 74 | /* |
| 75 | * The 64-bit value is not atomic on 32-bit systems - you MUST NOT read it |
| 76 | * without sampling the sequence number in jiffies_lock. |
| 77 | * get_jiffies_64() will do this for you as appropriate. |
| 78 | * |
| 79 | * jiffies and jiffies_64 are at the same address for little-endian systems |
| 80 | * and for 64-bit big-endian systems. |
| 81 | * On 32-bit big-endian systems, jiffies is the lower 32 bits of jiffies_64 |
| 82 | * (i.e., at address @jiffies_64 + 4). |
| 83 | * See arch/ARCH/kernel/vmlinux.lds.S |
| 84 | */ |
| 85 | extern u64 __cacheline_aligned_in_smp jiffies_64; |
| 86 | extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies; |
| 87 | |
| 88 | #if (BITS_PER_LONG < 64) |
| 89 | u64 get_jiffies_64(void); |
| 90 | #else |
| 91 | /** |
| 92 | * get_jiffies_64 - read the 64-bit non-atomic jiffies_64 value |
| 93 | * |
| 94 | * When BITS_PER_LONG < 64, this uses sequence number sampling using |
| 95 | * jiffies_lock to protect the 64-bit read. |
| 96 | * |
| 97 | * Return: current 64-bit jiffies value |
| 98 | */ |
| 99 | static inline u64 get_jiffies_64(void) |
| 100 | { |
| 101 | return (u64)jiffies; |
| 102 | } |
| 103 | #endif |
| 104 | |
| 105 | /** |
| 106 | * DOC: General information about time_* inlines |
| 107 | * |
| 108 | * These inlines deal with timer wrapping correctly. You are strongly encouraged |
| 109 | * to use them: |
| 110 | * |
| 111 | * #. Because people otherwise forget |
| 112 | * #. Because if the timer wrap changes in future you won't have to alter your |
| 113 | * driver code. |
| 114 | */ |
| 115 | |
| 116 | /** |
| 117 | * time_after - returns true if the time a is after time b. |
| 118 | * @a: first comparable as unsigned long |
| 119 | * @b: second comparable as unsigned long |
| 120 | * |
| 121 | * Do this with "<0" and ">=0" to only test the sign of the result. A |
| 122 | * good compiler would generate better code (and a really good compiler |
| 123 | * wouldn't care). Gcc is currently neither. |
| 124 | * |
| 125 | * Return: %true is time a is after time b, otherwise %false. |
| 126 | */ |
| 127 | #define time_after(a,b) \ |
| 128 | (typecheck(unsigned long, a) && \ |
| 129 | typecheck(unsigned long, b) && \ |
| 130 | ((long)((b) - (a)) < 0)) |
| 131 | /** |
| 132 | * time_before - returns true if the time a is before time b. |
| 133 | * @a: first comparable as unsigned long |
| 134 | * @b: second comparable as unsigned long |
| 135 | * |
| 136 | * Return: %true is time a is before time b, otherwise %false. |
| 137 | */ |
| 138 | #define time_before(a,b) time_after(b,a) |
| 139 | |
| 140 | /** |
| 141 | * time_after_eq - returns true if the time a is after or the same as time b. |
| 142 | * @a: first comparable as unsigned long |
| 143 | * @b: second comparable as unsigned long |
| 144 | * |
| 145 | * Return: %true is time a is after or the same as time b, otherwise %false. |
| 146 | */ |
| 147 | #define time_after_eq(a,b) \ |
| 148 | (typecheck(unsigned long, a) && \ |
| 149 | typecheck(unsigned long, b) && \ |
| 150 | ((long)((a) - (b)) >= 0)) |
| 151 | /** |
| 152 | * time_before_eq - returns true if the time a is before or the same as time b. |
| 153 | * @a: first comparable as unsigned long |
| 154 | * @b: second comparable as unsigned long |
| 155 | * |
| 156 | * Return: %true is time a is before or the same as time b, otherwise %false. |
| 157 | */ |
| 158 | #define time_before_eq(a,b) time_after_eq(b,a) |
| 159 | |
| 160 | /** |
| 161 | * time_in_range - Calculate whether a is in the range of [b, c]. |
| 162 | * @a: time to test |
| 163 | * @b: beginning of the range |
| 164 | * @c: end of the range |
| 165 | * |
| 166 | * Return: %true is time a is in the range [b, c], otherwise %false. |
| 167 | */ |
| 168 | #define time_in_range(a,b,c) \ |
| 169 | (time_after_eq(a,b) && \ |
| 170 | time_before_eq(a,c)) |
| 171 | |
| 172 | /** |
| 173 | * time_in_range_open - Calculate whether a is in the range of [b, c). |
| 174 | * @a: time to test |
| 175 | * @b: beginning of the range |
| 176 | * @c: end of the range |
| 177 | * |
| 178 | * Return: %true is time a is in the range [b, c), otherwise %false. |
| 179 | */ |
| 180 | #define time_in_range_open(a,b,c) \ |
| 181 | (time_after_eq(a,b) && \ |
| 182 | time_before(a,c)) |
| 183 | |
| 184 | /* Same as above, but does so with platform independent 64bit types. |
| 185 | * These must be used when utilizing jiffies_64 (i.e. return value of |
| 186 | * get_jiffies_64()). */ |
| 187 | |
| 188 | /** |
| 189 | * time_after64 - returns true if the time a is after time b. |
| 190 | * @a: first comparable as __u64 |
| 191 | * @b: second comparable as __u64 |
| 192 | * |
| 193 | * This must be used when utilizing jiffies_64 (i.e. return value of |
| 194 | * get_jiffies_64()). |
| 195 | * |
| 196 | * Return: %true is time a is after time b, otherwise %false. |
| 197 | */ |
| 198 | #define time_after64(a,b) \ |
| 199 | (typecheck(__u64, a) && \ |
| 200 | typecheck(__u64, b) && \ |
| 201 | ((__s64)((b) - (a)) < 0)) |
| 202 | /** |
| 203 | * time_before64 - returns true if the time a is before time b. |
| 204 | * @a: first comparable as __u64 |
| 205 | * @b: second comparable as __u64 |
| 206 | * |
| 207 | * This must be used when utilizing jiffies_64 (i.e. return value of |
| 208 | * get_jiffies_64()). |
| 209 | * |
| 210 | * Return: %true is time a is before time b, otherwise %false. |
| 211 | */ |
| 212 | #define time_before64(a,b) time_after64(b,a) |
| 213 | |
| 214 | /** |
| 215 | * time_after_eq64 - returns true if the time a is after or the same as time b. |
| 216 | * @a: first comparable as __u64 |
| 217 | * @b: second comparable as __u64 |
| 218 | * |
| 219 | * This must be used when utilizing jiffies_64 (i.e. return value of |
| 220 | * get_jiffies_64()). |
| 221 | * |
| 222 | * Return: %true is time a is after or the same as time b, otherwise %false. |
| 223 | */ |
| 224 | #define time_after_eq64(a,b) \ |
| 225 | (typecheck(__u64, a) && \ |
| 226 | typecheck(__u64, b) && \ |
| 227 | ((__s64)((a) - (b)) >= 0)) |
| 228 | /** |
| 229 | * time_before_eq64 - returns true if the time a is before or the same as time b. |
| 230 | * @a: first comparable as __u64 |
| 231 | * @b: second comparable as __u64 |
| 232 | * |
| 233 | * This must be used when utilizing jiffies_64 (i.e. return value of |
| 234 | * get_jiffies_64()). |
| 235 | * |
| 236 | * Return: %true is time a is before or the same as time b, otherwise %false. |
| 237 | */ |
| 238 | #define time_before_eq64(a,b) time_after_eq64(b,a) |
| 239 | |
| 240 | /** |
| 241 | * time_in_range64 - Calculate whether a is in the range of [b, c]. |
| 242 | * @a: time to test |
| 243 | * @b: beginning of the range |
| 244 | * @c: end of the range |
| 245 | * |
| 246 | * Return: %true is time a is in the range [b, c], otherwise %false. |
| 247 | */ |
| 248 | #define time_in_range64(a, b, c) \ |
| 249 | (time_after_eq64(a, b) && \ |
| 250 | time_before_eq64(a, c)) |
| 251 | |
| 252 | /* |
| 253 | * These eight macros compare jiffies[_64] and 'a' for convenience. |
| 254 | */ |
| 255 | |
| 256 | /** |
| 257 | * time_is_before_jiffies - return true if a is before jiffies |
| 258 | * @a: time (unsigned long) to compare to jiffies |
| 259 | * |
| 260 | * Return: %true is time a is before jiffies, otherwise %false. |
| 261 | */ |
| 262 | #define time_is_before_jiffies(a) time_after(jiffies, a) |
| 263 | /** |
| 264 | * time_is_before_jiffies64 - return true if a is before jiffies_64 |
| 265 | * @a: time (__u64) to compare to jiffies_64 |
| 266 | * |
| 267 | * Return: %true is time a is before jiffies_64, otherwise %false. |
| 268 | */ |
| 269 | #define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a) |
| 270 | |
| 271 | /** |
| 272 | * time_is_after_jiffies - return true if a is after jiffies |
| 273 | * @a: time (unsigned long) to compare to jiffies |
| 274 | * |
| 275 | * Return: %true is time a is after jiffies, otherwise %false. |
| 276 | */ |
| 277 | #define time_is_after_jiffies(a) time_before(jiffies, a) |
| 278 | /** |
| 279 | * time_is_after_jiffies64 - return true if a is after jiffies_64 |
| 280 | * @a: time (__u64) to compare to jiffies_64 |
| 281 | * |
| 282 | * Return: %true is time a is after jiffies_64, otherwise %false. |
| 283 | */ |
| 284 | #define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a) |
| 285 | |
| 286 | /** |
| 287 | * time_is_before_eq_jiffies - return true if a is before or equal to jiffies |
| 288 | * @a: time (unsigned long) to compare to jiffies |
| 289 | * |
| 290 | * Return: %true is time a is before or the same as jiffies, otherwise %false. |
| 291 | */ |
| 292 | #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a) |
| 293 | /** |
| 294 | * time_is_before_eq_jiffies64 - return true if a is before or equal to jiffies_64 |
| 295 | * @a: time (__u64) to compare to jiffies_64 |
| 296 | * |
| 297 | * Return: %true is time a is before or the same jiffies_64, otherwise %false. |
| 298 | */ |
| 299 | #define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a) |
| 300 | |
| 301 | /** |
| 302 | * time_is_after_eq_jiffies - return true if a is after or equal to jiffies |
| 303 | * @a: time (unsigned long) to compare to jiffies |
| 304 | * |
| 305 | * Return: %true is time a is after or the same as jiffies, otherwise %false. |
| 306 | */ |
| 307 | #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a) |
| 308 | /** |
| 309 | * time_is_after_eq_jiffies64 - return true if a is after or equal to jiffies_64 |
| 310 | * @a: time (__u64) to compare to jiffies_64 |
| 311 | * |
| 312 | * Return: %true is time a is after or the same as jiffies_64, otherwise %false. |
| 313 | */ |
| 314 | #define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a) |
| 315 | |
| 316 | /* |
| 317 | * Have the 32-bit jiffies value wrap 5 minutes after boot |
| 318 | * so jiffies wrap bugs show up earlier. |
| 319 | */ |
| 320 | #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) |
| 321 | |
| 322 | /* |
| 323 | * Change timeval to jiffies, trying to avoid the |
| 324 | * most obvious overflows.. |
| 325 | * |
| 326 | * And some not so obvious. |
| 327 | * |
| 328 | * Note that we don't want to return LONG_MAX, because |
| 329 | * for various timeout reasons we often end up having |
| 330 | * to wait "jiffies+1" in order to guarantee that we wait |
| 331 | * at _least_ "jiffies" - so "jiffies+1" had better still |
| 332 | * be positive. |
| 333 | */ |
| 334 | #define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1) |
| 335 | |
| 336 | extern unsigned long preset_lpj; |
| 337 | |
| 338 | /* |
| 339 | * We want to do realistic conversions of time so we need to use the same |
| 340 | * values the update wall clock code uses as the jiffies size. This value |
| 341 | * is: TICK_NSEC (which is defined in timex.h). This |
| 342 | * is a constant and is in nanoseconds. We will use scaled math |
| 343 | * with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and |
| 344 | * NSEC_JIFFIE_SC. Note that these defines contain nothing but |
| 345 | * constants and so are computed at compile time. SHIFT_HZ (computed in |
| 346 | * timex.h) adjusts the scaling for different HZ values. |
| 347 | |
| 348 | * Scaled math??? What is that? |
| 349 | * |
| 350 | * Scaled math is a way to do integer math on values that would, |
| 351 | * otherwise, either overflow, underflow, or cause undesired div |
| 352 | * instructions to appear in the execution path. In short, we "scale" |
| 353 | * up the operands so they take more bits (more precision, less |
| 354 | * underflow), do the desired operation and then "scale" the result back |
| 355 | * by the same amount. If we do the scaling by shifting we avoid the |
| 356 | * costly mpy and the dastardly div instructions. |
| 357 | |
| 358 | * Suppose, for example, we want to convert from seconds to jiffies |
| 359 | * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The |
| 360 | * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We |
| 361 | * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we |
| 362 | * might calculate at compile time, however, the result will only have |
| 363 | * about 3-4 bits of precision (less for smaller values of HZ). |
| 364 | * |
| 365 | * So, we scale as follows: |
| 366 | * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE); |
| 367 | * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE; |
| 368 | * Then we make SCALE a power of two so: |
| 369 | * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE; |
| 370 | * Now we define: |
| 371 | * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) |
| 372 | * jiff = (sec * SEC_CONV) >> SCALE; |
| 373 | * |
| 374 | * Often the math we use will expand beyond 32-bits so we tell C how to |
| 375 | * do this and pass the 64-bit result of the mpy through the ">> SCALE" |
| 376 | * which should take the result back to 32-bits. We want this expansion |
| 377 | * to capture as much precision as possible. At the same time we don't |
| 378 | * want to overflow so we pick the SCALE to avoid this. In this file, |
| 379 | * that means using a different scale for each range of HZ values (as |
| 380 | * defined in timex.h). |
| 381 | * |
| 382 | * For those who want to know, gcc will give a 64-bit result from a "*" |
| 383 | * operator if the result is a long long AND at least one of the |
| 384 | * operands is cast to long long (usually just prior to the "*" so as |
| 385 | * not to confuse it into thinking it really has a 64-bit operand, |
| 386 | * which, buy the way, it can do, but it takes more code and at least 2 |
| 387 | * mpys). |
| 388 | |
| 389 | * We also need to be aware that one second in nanoseconds is only a |
| 390 | * couple of bits away from overflowing a 32-bit word, so we MUST use |
| 391 | * 64-bits to get the full range time in nanoseconds. |
| 392 | |
| 393 | */ |
| 394 | |
| 395 | /* |
| 396 | * Here are the scales we will use. One for seconds, nanoseconds and |
| 397 | * microseconds. |
| 398 | * |
| 399 | * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and |
| 400 | * check if the sign bit is set. If not, we bump the shift count by 1. |
| 401 | * (Gets an extra bit of precision where we can use it.) |
| 402 | * We know it is set for HZ = 1024 and HZ = 100 not for 1000. |
| 403 | * Haven't tested others. |
| 404 | |
| 405 | * Limits of cpp (for #if expressions) only long (no long long), but |
| 406 | * then we only need the most signicant bit. |
| 407 | */ |
| 408 | |
| 409 | #define SEC_JIFFIE_SC (31 - SHIFT_HZ) |
| 410 | #if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000) |
| 411 | #undef SEC_JIFFIE_SC |
| 412 | #define SEC_JIFFIE_SC (32 - SHIFT_HZ) |
| 413 | #endif |
| 414 | #define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29) |
| 415 | #define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\ |
| 416 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
| 417 | |
| 418 | #define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\ |
| 419 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
| 420 | /* |
| 421 | * The maximum jiffie value is (MAX_INT >> 1). Here we translate that |
| 422 | * into seconds. The 64-bit case will overflow if we are not careful, |
| 423 | * so use the messy SH_DIV macro to do it. Still all constants. |
| 424 | */ |
| 425 | #if BITS_PER_LONG < 64 |
| 426 | # define MAX_SEC_IN_JIFFIES \ |
| 427 | (long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC) |
| 428 | #else /* take care of overflow on 64-bit machines */ |
| 429 | # define MAX_SEC_IN_JIFFIES \ |
| 430 | (SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1) |
| 431 | |
| 432 | #endif |
| 433 | |
| 434 | /* |
| 435 | * Convert various time units to each other: |
| 436 | */ |
| 437 | extern unsigned int jiffies_to_msecs(const unsigned long j); |
| 438 | extern unsigned int jiffies_to_usecs(const unsigned long j); |
| 439 | |
| 440 | /** |
| 441 | * jiffies_to_nsecs - Convert jiffies to nanoseconds |
| 442 | * @j: jiffies value |
| 443 | * |
| 444 | * Return: nanoseconds value |
| 445 | */ |
| 446 | static inline u64 jiffies_to_nsecs(const unsigned long j) |
| 447 | { |
| 448 | return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC; |
| 449 | } |
| 450 | |
| 451 | extern u64 jiffies64_to_nsecs(u64 j); |
| 452 | extern u64 jiffies64_to_msecs(u64 j); |
| 453 | |
| 454 | extern unsigned long __msecs_to_jiffies(const unsigned int m); |
| 455 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
| 456 | /* |
| 457 | * HZ is equal to or smaller than 1000, and 1000 is a nice round |
| 458 | * multiple of HZ, divide with the factor between them, but round |
| 459 | * upwards: |
| 460 | */ |
| 461 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| 462 | { |
| 463 | return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); |
| 464 | } |
| 465 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
| 466 | /* |
| 467 | * HZ is larger than 1000, and HZ is a nice round multiple of 1000 - |
| 468 | * simply multiply with the factor between them. |
| 469 | * |
| 470 | * But first make sure the multiplication result cannot overflow: |
| 471 | */ |
| 472 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| 473 | { |
| 474 | if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 475 | return MAX_JIFFY_OFFSET; |
| 476 | return m * (HZ / MSEC_PER_SEC); |
| 477 | } |
| 478 | #else |
| 479 | /* |
| 480 | * Generic case - multiply, round and divide. But first check that if |
| 481 | * we are doing a net multiplication, that we wouldn't overflow: |
| 482 | */ |
| 483 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| 484 | { |
| 485 | if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| 486 | return MAX_JIFFY_OFFSET; |
| 487 | |
| 488 | return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> MSEC_TO_HZ_SHR32; |
| 489 | } |
| 490 | #endif |
| 491 | /** |
| 492 | * msecs_to_jiffies: - convert milliseconds to jiffies |
| 493 | * @m: time in milliseconds |
| 494 | * |
| 495 | * conversion is done as follows: |
| 496 | * |
| 497 | * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) |
| 498 | * |
| 499 | * - 'too large' values [that would result in larger than |
| 500 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| 501 | * |
| 502 | * - all other values are converted to jiffies by either multiplying |
| 503 | * the input value by a factor or dividing it with a factor and |
| 504 | * handling any 32-bit overflows. |
| 505 | * for the details see __msecs_to_jiffies() |
| 506 | * |
| 507 | * msecs_to_jiffies() checks for the passed in value being a constant |
| 508 | * via __builtin_constant_p() allowing gcc to eliminate most of the |
| 509 | * code. __msecs_to_jiffies() is called if the value passed does not |
| 510 | * allow constant folding and the actual conversion must be done at |
| 511 | * runtime. |
| 512 | * The HZ range specific helpers _msecs_to_jiffies() are called both |
| 513 | * directly here and from __msecs_to_jiffies() in the case where |
| 514 | * constant folding is not possible. |
| 515 | * |
| 516 | * Return: jiffies value |
| 517 | */ |
| 518 | static __always_inline unsigned long msecs_to_jiffies(const unsigned int m) |
| 519 | { |
| 520 | if (__builtin_constant_p(m)) { |
| 521 | if ((int)m < 0) |
| 522 | return MAX_JIFFY_OFFSET; |
| 523 | return _msecs_to_jiffies(m); |
| 524 | } else { |
| 525 | return __msecs_to_jiffies(m); |
| 526 | } |
| 527 | } |
| 528 | |
| 529 | extern unsigned long __usecs_to_jiffies(const unsigned int u); |
| 530 | #if !(USEC_PER_SEC % HZ) |
| 531 | static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
| 532 | { |
| 533 | return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); |
| 534 | } |
| 535 | #else |
| 536 | static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
| 537 | { |
| 538 | return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) |
| 539 | >> USEC_TO_HZ_SHR32; |
| 540 | } |
| 541 | #endif |
| 542 | |
| 543 | /** |
| 544 | * usecs_to_jiffies: - convert microseconds to jiffies |
| 545 | * @u: time in microseconds |
| 546 | * |
| 547 | * conversion is done as follows: |
| 548 | * |
| 549 | * - 'too large' values [that would result in larger than |
| 550 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| 551 | * |
| 552 | * - all other values are converted to jiffies by either multiplying |
| 553 | * the input value by a factor or dividing it with a factor and |
| 554 | * handling any 32-bit overflows as for msecs_to_jiffies. |
| 555 | * |
| 556 | * usecs_to_jiffies() checks for the passed in value being a constant |
| 557 | * via __builtin_constant_p() allowing gcc to eliminate most of the |
| 558 | * code. __usecs_to_jiffies() is called if the value passed does not |
| 559 | * allow constant folding and the actual conversion must be done at |
| 560 | * runtime. |
| 561 | * The HZ range specific helpers _usecs_to_jiffies() are called both |
| 562 | * directly here and from __msecs_to_jiffies() in the case where |
| 563 | * constant folding is not possible. |
| 564 | * |
| 565 | * Return: jiffies value |
| 566 | */ |
| 567 | static __always_inline unsigned long usecs_to_jiffies(const unsigned int u) |
| 568 | { |
| 569 | if (__builtin_constant_p(u)) { |
| 570 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) |
| 571 | return MAX_JIFFY_OFFSET; |
| 572 | return _usecs_to_jiffies(u); |
| 573 | } else { |
| 574 | return __usecs_to_jiffies(u); |
| 575 | } |
| 576 | } |
| 577 | |
| 578 | extern unsigned long timespec64_to_jiffies(const struct timespec64 *value); |
| 579 | extern void jiffies_to_timespec64(const unsigned long jiffies, |
| 580 | struct timespec64 *value); |
| 581 | extern clock_t jiffies_to_clock_t(unsigned long x); |
| 582 | |
| 583 | static inline clock_t jiffies_delta_to_clock_t(long delta) |
| 584 | { |
| 585 | return jiffies_to_clock_t(max(0L, delta)); |
| 586 | } |
| 587 | |
| 588 | static inline unsigned int jiffies_delta_to_msecs(long delta) |
| 589 | { |
| 590 | return jiffies_to_msecs(max(0L, delta)); |
| 591 | } |
| 592 | |
| 593 | extern unsigned long clock_t_to_jiffies(unsigned long x); |
| 594 | extern u64 jiffies_64_to_clock_t(u64 x); |
| 595 | extern u64 nsec_to_clock_t(u64 x); |
| 596 | extern u64 nsecs_to_jiffies64(u64 n); |
| 597 | extern unsigned long nsecs_to_jiffies(u64 n); |
| 598 | |
| 599 | #define TIMESTAMP_SIZE 30 |
| 600 | |
| 601 | #endif |