6377981faf
A machine check can interrupt the i/o and external interrupt handler anytime. If the machine check occurs while the interrupt handler is waking up from idle vtime_start_cpu can get executed a second time and the int_clock / async_enter_timer values in the lowcore get clobbered. This can confuse the cpu time accounting. To fix this problem two changes are needed. First the machine check handler has to use its own copies of int_clock and async_enter_timer, named mcck_clock and mcck_enter_timer. Second the nested execution of vtime_start_cpu has to be prevented. This is done in s390_idle_check by checking the wait bit in the program status word. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
211 lines
4.7 KiB
C
211 lines
4.7 KiB
C
/*
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* include/asm-s390/cputime.h
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*
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* (C) Copyright IBM Corp. 2004
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*
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* Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#ifndef _S390_CPUTIME_H
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#define _S390_CPUTIME_H
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#include <linux/types.h>
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#include <linux/percpu.h>
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#include <linux/spinlock.h>
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#include <asm/div64.h>
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/* We want to use full resolution of the CPU timer: 2**-12 micro-seconds. */
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typedef unsigned long long cputime_t;
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typedef unsigned long long cputime64_t;
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#ifndef __s390x__
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static inline unsigned int
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__div(unsigned long long n, unsigned int base)
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{
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register_pair rp;
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rp.pair = n >> 1;
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asm ("dr %0,%1" : "+d" (rp) : "d" (base >> 1));
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return rp.subreg.odd;
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}
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#else /* __s390x__ */
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static inline unsigned int
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__div(unsigned long long n, unsigned int base)
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{
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return n / base;
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}
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#endif /* __s390x__ */
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#define cputime_zero (0ULL)
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#define cputime_one_jiffy jiffies_to_cputime(1)
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#define cputime_max ((~0UL >> 1) - 1)
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#define cputime_add(__a, __b) ((__a) + (__b))
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#define cputime_sub(__a, __b) ((__a) - (__b))
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#define cputime_div(__a, __n) ({ \
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unsigned long long __div = (__a); \
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do_div(__div,__n); \
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__div; \
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})
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#define cputime_halve(__a) ((__a) >> 1)
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#define cputime_eq(__a, __b) ((__a) == (__b))
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#define cputime_gt(__a, __b) ((__a) > (__b))
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#define cputime_ge(__a, __b) ((__a) >= (__b))
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#define cputime_lt(__a, __b) ((__a) < (__b))
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#define cputime_le(__a, __b) ((__a) <= (__b))
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#define cputime_to_jiffies(__ct) (__div((__ct), 4096000000ULL / HZ))
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#define cputime_to_scaled(__ct) (__ct)
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#define jiffies_to_cputime(__hz) ((cputime_t)(__hz) * (4096000000ULL / HZ))
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#define cputime64_zero (0ULL)
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#define cputime64_add(__a, __b) ((__a) + (__b))
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#define cputime_to_cputime64(__ct) (__ct)
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static inline u64
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cputime64_to_jiffies64(cputime64_t cputime)
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{
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do_div(cputime, 4096000000ULL / HZ);
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return cputime;
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}
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/*
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* Convert cputime to milliseconds and back.
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*/
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static inline unsigned int
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cputime_to_msecs(const cputime_t cputime)
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{
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return cputime_div(cputime, 4096000);
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}
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static inline cputime_t
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msecs_to_cputime(const unsigned int m)
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{
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return (cputime_t) m * 4096000;
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}
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/*
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* Convert cputime to milliseconds and back.
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*/
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static inline unsigned int
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cputime_to_secs(const cputime_t cputime)
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{
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return __div(cputime, 2048000000) >> 1;
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}
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static inline cputime_t
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secs_to_cputime(const unsigned int s)
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{
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return (cputime_t) s * 4096000000ULL;
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}
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/*
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* Convert cputime to timespec and back.
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*/
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static inline cputime_t
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timespec_to_cputime(const struct timespec *value)
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{
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return value->tv_nsec * 4096 / 1000 + (u64) value->tv_sec * 4096000000ULL;
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}
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static inline void
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cputime_to_timespec(const cputime_t cputime, struct timespec *value)
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{
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#ifndef __s390x__
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register_pair rp;
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rp.pair = cputime >> 1;
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asm ("dr %0,%1" : "+d" (rp) : "d" (2048000000UL));
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value->tv_nsec = rp.subreg.even * 1000 / 4096;
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value->tv_sec = rp.subreg.odd;
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#else
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value->tv_nsec = (cputime % 4096000000ULL) * 1000 / 4096;
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value->tv_sec = cputime / 4096000000ULL;
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#endif
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}
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/*
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* Convert cputime to timeval and back.
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* Since cputime and timeval have the same resolution (microseconds)
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* this is easy.
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*/
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static inline cputime_t
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timeval_to_cputime(const struct timeval *value)
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{
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return value->tv_usec * 4096 + (u64) value->tv_sec * 4096000000ULL;
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}
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static inline void
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cputime_to_timeval(const cputime_t cputime, struct timeval *value)
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{
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#ifndef __s390x__
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register_pair rp;
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rp.pair = cputime >> 1;
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asm ("dr %0,%1" : "+d" (rp) : "d" (2048000000UL));
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value->tv_usec = rp.subreg.even / 4096;
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value->tv_sec = rp.subreg.odd;
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#else
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value->tv_usec = (cputime % 4096000000ULL) / 4096;
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value->tv_sec = cputime / 4096000000ULL;
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#endif
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}
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/*
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* Convert cputime to clock and back.
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*/
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static inline clock_t
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cputime_to_clock_t(cputime_t cputime)
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{
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return cputime_div(cputime, 4096000000ULL / USER_HZ);
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}
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static inline cputime_t
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clock_t_to_cputime(unsigned long x)
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{
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return (cputime_t) x * (4096000000ULL / USER_HZ);
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}
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/*
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* Convert cputime64 to clock.
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*/
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static inline clock_t
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cputime64_to_clock_t(cputime64_t cputime)
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{
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return cputime_div(cputime, 4096000000ULL / USER_HZ);
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}
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struct s390_idle_data {
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unsigned int sequence;
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unsigned long long idle_count;
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unsigned long long idle_enter;
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unsigned long long idle_time;
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int nohz_delay;
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};
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DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
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void vtime_start_cpu(__u64 int_clock, __u64 enter_timer);
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cputime64_t s390_get_idle_time(int cpu);
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#define arch_idle_time(cpu) s390_get_idle_time(cpu)
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static inline void s390_idle_check(struct pt_regs *regs, __u64 int_clock,
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__u64 enter_timer)
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{
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if (regs->psw.mask & PSW_MASK_WAIT)
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vtime_start_cpu(int_clock, enter_timer);
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}
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static inline int s390_nohz_delay(int cpu)
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{
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return per_cpu(s390_idle, cpu).nohz_delay != 0;
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}
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#define arch_needs_cpu(cpu) s390_nohz_delay(cpu)
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#endif /* _S390_CPUTIME_H */
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