| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _LINUX_JIFFIES_H |
| #define _LINUX_JIFFIES_H |
| |
| #include <linux/cache.h> |
| #include <linux/math64.h> |
| #include <linux/kernel.h> |
| #include <linux/types.h> |
| #include <linux/time.h> |
| #include <linux/timex.h> |
| #include <asm/param.h> /* for HZ */ |
| #include <generated/timeconst.h> |
| |
| /* |
| * The following defines establish the engineering parameters of the PLL |
| * model. The HZ variable establishes the timer interrupt frequency, 100 Hz |
| * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the |
| * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the |
| * nearest power of two in order to avoid hardware multiply operations. |
| */ |
| #if HZ >= 12 && HZ < 24 |
| # define SHIFT_HZ 4 |
| #elif HZ >= 24 && HZ < 48 |
| # define SHIFT_HZ 5 |
| #elif HZ >= 48 && HZ < 96 |
| # define SHIFT_HZ 6 |
| #elif HZ >= 96 && HZ < 192 |
| # define SHIFT_HZ 7 |
| #elif HZ >= 192 && HZ < 384 |
| # define SHIFT_HZ 8 |
| #elif HZ >= 384 && HZ < 768 |
| # define SHIFT_HZ 9 |
| #elif HZ >= 768 && HZ < 1536 |
| # define SHIFT_HZ 10 |
| #elif HZ >= 1536 && HZ < 3072 |
| # define SHIFT_HZ 11 |
| #elif HZ >= 3072 && HZ < 6144 |
| # define SHIFT_HZ 12 |
| #elif HZ >= 6144 && HZ < 12288 |
| # define SHIFT_HZ 13 |
| #else |
| # error Invalid value of HZ. |
| #endif |
| |
| /* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can |
| * improve accuracy by shifting LSH bits, hence calculating: |
| * (NOM << LSH) / DEN |
| * This however means trouble for large NOM, because (NOM << LSH) may no |
| * longer fit in 32 bits. The following way of calculating this gives us |
| * some slack, under the following conditions: |
| * - (NOM / DEN) fits in (32 - LSH) bits. |
| * - (NOM % DEN) fits in (32 - LSH) bits. |
| */ |
| #define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \ |
| + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN)) |
| |
| /* LATCH is used in the interval timer and ftape setup. */ |
| #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ |
| |
| extern int register_refined_jiffies(long clock_tick_rate); |
| |
| /* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */ |
| #define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ) |
| |
| /* TICK_USEC is the time between ticks in usec assuming SHIFTED_HZ */ |
| #define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ) |
| |
| /* USER_TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ |
| #define USER_TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) |
| |
| #ifndef __jiffy_arch_data |
| #define __jiffy_arch_data |
| #endif |
| |
| /* |
| * The 64-bit value is not atomic - you MUST NOT read it |
| * without sampling the sequence number in jiffies_lock. |
| * get_jiffies_64() will do this for you as appropriate. |
| */ |
| extern u64 __cacheline_aligned_in_smp jiffies_64; |
| extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies; |
| |
| #if (BITS_PER_LONG < 64) |
| u64 get_jiffies_64(void); |
| #else |
| static inline u64 get_jiffies_64(void) |
| { |
| return (u64)jiffies; |
| } |
| #endif |
| |
| /* |
| * These inlines deal with timer wrapping correctly. You are |
| * strongly encouraged to use them |
| * 1. Because people otherwise forget |
| * 2. Because if the timer wrap changes in future you won't have to |
| * alter your driver code. |
| * |
| * time_after(a,b) returns true if the time a is after time b. |
| * |
| * Do this with "<0" and ">=0" to only test the sign of the result. A |
| * good compiler would generate better code (and a really good compiler |
| * wouldn't care). Gcc is currently neither. |
| */ |
| #define time_after(a,b) \ |
| (typecheck(unsigned long, a) && \ |
| typecheck(unsigned long, b) && \ |
| ((long)((b) - (a)) < 0)) |
| #define time_before(a,b) time_after(b,a) |
| |
| #define time_after_eq(a,b) \ |
| (typecheck(unsigned long, a) && \ |
| typecheck(unsigned long, b) && \ |
| ((long)((a) - (b)) >= 0)) |
| #define time_before_eq(a,b) time_after_eq(b,a) |
| |
| /* |
| * Calculate whether a is in the range of [b, c]. |
| */ |
| #define time_in_range(a,b,c) \ |
| (time_after_eq(a,b) && \ |
| time_before_eq(a,c)) |
| |
| /* |
| * Calculate whether a is in the range of [b, c). |
| */ |
| #define time_in_range_open(a,b,c) \ |
| (time_after_eq(a,b) && \ |
| time_before(a,c)) |
| |
| /* Same as above, but does so with platform independent 64bit types. |
| * These must be used when utilizing jiffies_64 (i.e. return value of |
| * get_jiffies_64() */ |
| #define time_after64(a,b) \ |
| (typecheck(__u64, a) && \ |
| typecheck(__u64, b) && \ |
| ((__s64)((b) - (a)) < 0)) |
| #define time_before64(a,b) time_after64(b,a) |
| |
| #define time_after_eq64(a,b) \ |
| (typecheck(__u64, a) && \ |
| typecheck(__u64, b) && \ |
| ((__s64)((a) - (b)) >= 0)) |
| #define time_before_eq64(a,b) time_after_eq64(b,a) |
| |
| #define time_in_range64(a, b, c) \ |
| (time_after_eq64(a, b) && \ |
| time_before_eq64(a, c)) |
| |
| /* |
| * These four macros compare jiffies and 'a' for convenience. |
| */ |
| |
| /* time_is_before_jiffies(a) return true if a is before jiffies */ |
| #define time_is_before_jiffies(a) time_after(jiffies, a) |
| #define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a) |
| |
| /* time_is_after_jiffies(a) return true if a is after jiffies */ |
| #define time_is_after_jiffies(a) time_before(jiffies, a) |
| #define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a) |
| |
| /* time_is_before_eq_jiffies(a) return true if a is before or equal to jiffies*/ |
| #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a) |
| #define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a) |
| |
| /* time_is_after_eq_jiffies(a) return true if a is after or equal to jiffies*/ |
| #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a) |
| #define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a) |
| |
| /* |
| * Have the 32 bit jiffies value wrap 5 minutes after boot |
| * so jiffies wrap bugs show up earlier. |
| */ |
| #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) |
| |
| /* |
| * Change timeval to jiffies, trying to avoid the |
| * most obvious overflows.. |
| * |
| * And some not so obvious. |
| * |
| * Note that we don't want to return LONG_MAX, because |
| * for various timeout reasons we often end up having |
| * to wait "jiffies+1" in order to guarantee that we wait |
| * at _least_ "jiffies" - so "jiffies+1" had better still |
| * be positive. |
| */ |
| #define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1) |
| |
| extern unsigned long preset_lpj; |
| |
| /* |
| * We want to do realistic conversions of time so we need to use the same |
| * values the update wall clock code uses as the jiffies size. This value |
| * is: TICK_NSEC (which is defined in timex.h). This |
| * is a constant and is in nanoseconds. We will use scaled math |
| * with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and |
| * NSEC_JIFFIE_SC. Note that these defines contain nothing but |
| * constants and so are computed at compile time. SHIFT_HZ (computed in |
| * timex.h) adjusts the scaling for different HZ values. |
| |
| * Scaled math??? What is that? |
| * |
| * Scaled math is a way to do integer math on values that would, |
| * otherwise, either overflow, underflow, or cause undesired div |
| * instructions to appear in the execution path. In short, we "scale" |
| * up the operands so they take more bits (more precision, less |
| * underflow), do the desired operation and then "scale" the result back |
| * by the same amount. If we do the scaling by shifting we avoid the |
| * costly mpy and the dastardly div instructions. |
| |
| * Suppose, for example, we want to convert from seconds to jiffies |
| * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The |
| * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We |
| * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we |
| * might calculate at compile time, however, the result will only have |
| * about 3-4 bits of precision (less for smaller values of HZ). |
| * |
| * So, we scale as follows: |
| * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE); |
| * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE; |
| * Then we make SCALE a power of two so: |
| * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE; |
| * Now we define: |
| * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) |
| * jiff = (sec * SEC_CONV) >> SCALE; |
| * |
| * Often the math we use will expand beyond 32-bits so we tell C how to |
| * do this and pass the 64-bit result of the mpy through the ">> SCALE" |
| * which should take the result back to 32-bits. We want this expansion |
| * to capture as much precision as possible. At the same time we don't |
| * want to overflow so we pick the SCALE to avoid this. In this file, |
| * that means using a different scale for each range of HZ values (as |
| * defined in timex.h). |
| * |
| * For those who want to know, gcc will give a 64-bit result from a "*" |
| * operator if the result is a long long AND at least one of the |
| * operands is cast to long long (usually just prior to the "*" so as |
| * not to confuse it into thinking it really has a 64-bit operand, |
| * which, buy the way, it can do, but it takes more code and at least 2 |
| * mpys). |
| |
| * We also need to be aware that one second in nanoseconds is only a |
| * couple of bits away from overflowing a 32-bit word, so we MUST use |
| * 64-bits to get the full range time in nanoseconds. |
| |
| */ |
| |
| /* |
| * Here are the scales we will use. One for seconds, nanoseconds and |
| * microseconds. |
| * |
| * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and |
| * check if the sign bit is set. If not, we bump the shift count by 1. |
| * (Gets an extra bit of precision where we can use it.) |
| * We know it is set for HZ = 1024 and HZ = 100 not for 1000. |
| * Haven't tested others. |
| |
| * Limits of cpp (for #if expressions) only long (no long long), but |
| * then we only need the most signicant bit. |
| */ |
| |
| #define SEC_JIFFIE_SC (31 - SHIFT_HZ) |
| #if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000) |
| #undef SEC_JIFFIE_SC |
| #define SEC_JIFFIE_SC (32 - SHIFT_HZ) |
| #endif |
| #define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29) |
| #define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\ |
| TICK_NSEC -1) / (u64)TICK_NSEC)) |
| |
| #define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\ |
| TICK_NSEC -1) / (u64)TICK_NSEC)) |
| /* |
| * The maximum jiffie value is (MAX_INT >> 1). Here we translate that |
| * into seconds. The 64-bit case will overflow if we are not careful, |
| * so use the messy SH_DIV macro to do it. Still all constants. |
| */ |
| #if BITS_PER_LONG < 64 |
| # define MAX_SEC_IN_JIFFIES \ |
| (long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC) |
| #else /* take care of overflow on 64 bits machines */ |
| # define MAX_SEC_IN_JIFFIES \ |
| (SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1) |
| |
| #endif |
| |
| /* |
| * Convert various time units to each other: |
| */ |
| extern unsigned int jiffies_to_msecs(const unsigned long j); |
| extern unsigned int jiffies_to_usecs(const unsigned long j); |
| |
| static inline u64 jiffies_to_nsecs(const unsigned long j) |
| { |
| return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC; |
| } |
| |
| extern u64 jiffies64_to_nsecs(u64 j); |
| |
| extern unsigned long __msecs_to_jiffies(const unsigned int m); |
| #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
| /* |
| * HZ is equal to or smaller than 1000, and 1000 is a nice round |
| * multiple of HZ, divide with the factor between them, but round |
| * upwards: |
| */ |
| static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| { |
| return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); |
| } |
| #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
| /* |
| * HZ is larger than 1000, and HZ is a nice round multiple of 1000 - |
| * simply multiply with the factor between them. |
| * |
| * But first make sure the multiplication result cannot overflow: |
| */ |
| static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| { |
| if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| return MAX_JIFFY_OFFSET; |
| return m * (HZ / MSEC_PER_SEC); |
| } |
| #else |
| /* |
| * Generic case - multiply, round and divide. But first check that if |
| * we are doing a net multiplication, that we wouldn't overflow: |
| */ |
| static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
| { |
| if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
| return MAX_JIFFY_OFFSET; |
| |
| return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> MSEC_TO_HZ_SHR32; |
| } |
| #endif |
| /** |
| * msecs_to_jiffies: - convert milliseconds to jiffies |
| * @m: time in milliseconds |
| * |
| * conversion is done as follows: |
| * |
| * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) |
| * |
| * - 'too large' values [that would result in larger than |
| * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| * |
| * - all other values are converted to jiffies by either multiplying |
| * the input value by a factor or dividing it with a factor and |
| * handling any 32-bit overflows. |
| * for the details see __msecs_to_jiffies() |
| * |
| * msecs_to_jiffies() checks for the passed in value being a constant |
| * via __builtin_constant_p() allowing gcc to eliminate most of the |
| * code, __msecs_to_jiffies() is called if the value passed does not |
| * allow constant folding and the actual conversion must be done at |
| * runtime. |
| * the HZ range specific helpers _msecs_to_jiffies() are called both |
| * directly here and from __msecs_to_jiffies() in the case where |
| * constant folding is not possible. |
| */ |
| static __always_inline unsigned long msecs_to_jiffies(const unsigned int m) |
| { |
| if (__builtin_constant_p(m)) { |
| if ((int)m < 0) |
| return MAX_JIFFY_OFFSET; |
| return _msecs_to_jiffies(m); |
| } else { |
| return __msecs_to_jiffies(m); |
| } |
| } |
| |
| extern unsigned long __usecs_to_jiffies(const unsigned int u); |
| #if !(USEC_PER_SEC % HZ) |
| static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
| { |
| return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); |
| } |
| #else |
| static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
| { |
| return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) |
| >> USEC_TO_HZ_SHR32; |
| } |
| #endif |
| |
| /** |
| * usecs_to_jiffies: - convert microseconds to jiffies |
| * @u: time in microseconds |
| * |
| * conversion is done as follows: |
| * |
| * - 'too large' values [that would result in larger than |
| * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
| * |
| * - all other values are converted to jiffies by either multiplying |
| * the input value by a factor or dividing it with a factor and |
| * handling any 32-bit overflows as for msecs_to_jiffies. |
| * |
| * usecs_to_jiffies() checks for the passed in value being a constant |
| * via __builtin_constant_p() allowing gcc to eliminate most of the |
| * code, __usecs_to_jiffies() is called if the value passed does not |
| * allow constant folding and the actual conversion must be done at |
| * runtime. |
| * the HZ range specific helpers _usecs_to_jiffies() are called both |
| * directly here and from __msecs_to_jiffies() in the case where |
| * constant folding is not possible. |
| */ |
| static __always_inline unsigned long usecs_to_jiffies(const unsigned int u) |
| { |
| if (__builtin_constant_p(u)) { |
| if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) |
| return MAX_JIFFY_OFFSET; |
| return _usecs_to_jiffies(u); |
| } else { |
| return __usecs_to_jiffies(u); |
| } |
| } |
| |
| extern unsigned long timespec64_to_jiffies(const struct timespec64 *value); |
| extern void jiffies_to_timespec64(const unsigned long jiffies, |
| struct timespec64 *value); |
| static inline unsigned long timespec_to_jiffies(const struct timespec *value) |
| { |
| struct timespec64 ts = timespec_to_timespec64(*value); |
| |
| return timespec64_to_jiffies(&ts); |
| } |
| |
| static inline void jiffies_to_timespec(const unsigned long jiffies, |
| struct timespec *value) |
| { |
| struct timespec64 ts; |
| |
| jiffies_to_timespec64(jiffies, &ts); |
| *value = timespec64_to_timespec(ts); |
| } |
| |
| extern unsigned long timeval_to_jiffies(const struct timeval *value); |
| extern void jiffies_to_timeval(const unsigned long jiffies, |
| struct timeval *value); |
| |
| extern clock_t jiffies_to_clock_t(unsigned long x); |
| static inline clock_t jiffies_delta_to_clock_t(long delta) |
| { |
| return jiffies_to_clock_t(max(0L, delta)); |
| } |
| |
| extern unsigned long clock_t_to_jiffies(unsigned long x); |
| extern u64 jiffies_64_to_clock_t(u64 x); |
| extern u64 nsec_to_clock_t(u64 x); |
| extern u64 nsecs_to_jiffies64(u64 n); |
| extern unsigned long nsecs_to_jiffies(u64 n); |
| |
| #define TIMESTAMP_SIZE 30 |
| |
| #endif |