| Message ID | a1bd8d71caeb4051d0be87aad1baae7ababa4df7.1436511577.git.baolin.wang@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 15 July 2015 at 18:31, Thomas Gleixner <tglx@linutronix.de> wrote: > On Wed, 15 Jul 2015, Baolin Wang wrote: > >> The cputime_to_timespec() and timespec_to_cputime() functions are >> not year 2038 safe on 32bit systems due to that the struct timepsec >> will overflow in 2038 year. > > And how is this relevant? cputime is not based on wall clock time at > all. So what has 2038 to do with cputime? > > We want proper explanations WHY we need such a change. When converting the posix-cpu-timers, it call the cputime_to_timespec() function. Thus it need a conversion for this function. You can see that conversion in patch "posix-cpu-timers: Convert to y2038 safe callbacks" from https://git.linaro.org/people/baolin.wang/upstream_0627.git. And I also will explain this in the changelog. Thanks for your comments. > > Thanks, > > tglx > >
On 15 July 2015 at 19:55, Thomas Gleixner <tglx@linutronix.de> wrote: > On Wed, 15 Jul 2015, Baolin Wang wrote: > >> On 15 July 2015 at 18:31, Thomas Gleixner <tglx@linutronix.de> wrote: >> > On Wed, 15 Jul 2015, Baolin Wang wrote: >> > >> >> The cputime_to_timespec() and timespec_to_cputime() functions are >> >> not year 2038 safe on 32bit systems due to that the struct timepsec >> >> will overflow in 2038 year. >> > >> > And how is this relevant? cputime is not based on wall clock time at >> > all. So what has 2038 to do with cputime? >> > >> > We want proper explanations WHY we need such a change. >> >> When converting the posix-cpu-timers, it call the >> cputime_to_timespec() function. Thus it need a conversion for this >> function. > > There is no requirement to convert posix-cpu-timers on their own. We > need to adopt the posix cpu timers code because it shares syscalls > with the other posix timers, but that still does not explain why we > need these functions. > In posix-cpu-timers, it also defined some 'k_clock struct' variables, and we need to convert the callbacks of the 'k_clock struct' which are not year 2038 safe on 32bit systems. Some callbacks which need to convert call the cputime_to_timespec() function, thus we also want to convert the cputime_to_timespec() function to a year 2038 safe function to make all them ready for the year 2038 issue. >> You can see that conversion in patch "posix-cpu-timers: Convert to >> y2038 safe callbacks" from >> https://git.linaro.org/people/baolin.wang/upstream_0627.git. > > I do not care about your random git tree. I care about proper > changelogs. Your changelogs are just a copied boilerplate full of > errors. > > Thanks, > > tglx
On 16 July 2015 at 18:43, Thomas Gleixner <tglx@linutronix.de> wrote: > On Thu, 16 Jul 2015, Baolin Wang wrote: >> On 15 July 2015 at 19:55, Thomas Gleixner <tglx@linutronix.de> wrote: >> > On Wed, 15 Jul 2015, Baolin Wang wrote: >> > >> >> On 15 July 2015 at 18:31, Thomas Gleixner <tglx@linutronix.de> wrote: >> >> > On Wed, 15 Jul 2015, Baolin Wang wrote: >> >> > >> >> >> The cputime_to_timespec() and timespec_to_cputime() functions are >> >> >> not year 2038 safe on 32bit systems due to that the struct timepsec >> >> >> will overflow in 2038 year. >> >> > >> >> > And how is this relevant? cputime is not based on wall clock time at >> >> > all. So what has 2038 to do with cputime? >> >> > >> >> > We want proper explanations WHY we need such a change. >> >> >> >> When converting the posix-cpu-timers, it call the >> >> cputime_to_timespec() function. Thus it need a conversion for this >> >> function. >> > >> > There is no requirement to convert posix-cpu-timers on their own. We >> > need to adopt the posix cpu timers code because it shares syscalls >> > with the other posix timers, but that still does not explain why we >> > need these functions. >> > >> >> In posix-cpu-timers, it also defined some 'k_clock struct' variables, >> and we need to convert the callbacks of the 'k_clock struct' which are >> not year 2038 safe on 32bit systems. Some callbacks which need to >> convert call the cputime_to_timespec() function, thus we also want to >> convert the cputime_to_timespec() function to a year 2038 safe >> function to make all them ready for the year 2038 issue. > > You are not getting it at all. > > 1) We need to change k_clock callbacks due to 2038 issues > > 2) posix cpu timers implement affected callbacks > > 3) posix cpu timers themself and cputime are NOT affected by 2038 > > So we have 2 options to change the code in posix cpu timers: > > A) Do the timespec/timespec64 conversion in the posix cpu timer > callbacks and leave the cputime functions untouched. > > B) Implement cputime/timespec64 functions to avoid #A > > If you go for #B, you need to provide a reasonable explanation why > it is better than #A. And that explanation has absolutely nothing > to do with 2038 safety. Very thanks for your explanation, and I'll think about that. > > Not everything is a 2038 issue, just because the only tool you have is > a timespec64. > > Thanks, > > tglx > > >
diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h index e245255..5dda5c0 100644 --- a/arch/powerpc/include/asm/cputime.h +++ b/arch/powerpc/include/asm/cputime.h @@ -154,9 +154,9 @@ static inline cputime_t secs_to_cputime(const unsigned long sec) } /* - * Convert cputime <-> timespec + * Convert cputime <-> timespec64 */ -static inline void cputime_to_timespec(const cputime_t ct, struct timespec *p) +static inline void cputime_to_timespec64(const cputime_t ct, struct timespec64 *p) { u64 x = (__force u64) ct; unsigned int frac; @@ -168,7 +168,7 @@ static inline void cputime_to_timespec(const cputime_t ct, struct timespec *p) p->tv_nsec = x; } -static inline cputime_t timespec_to_cputime(const struct timespec *p) +static inline cputime_t timespec64_to_cputime(const struct timespec64 *p) { u64 ct; diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index 221b454..3319b51 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -81,16 +81,16 @@ static inline cputime_t secs_to_cputime(const unsigned int s) } /* - * Convert cputime to timespec and back. + * Convert cputime to timespec64 and back. */ -static inline cputime_t timespec_to_cputime(const struct timespec *value) +static inline cputime_t timespec64_to_cputime(const struct timespec64 *value) { unsigned long long ret = value->tv_sec * CPUTIME_PER_SEC; return (__force cputime_t)(ret + __div(value->tv_nsec * CPUTIME_PER_USEC, NSEC_PER_USEC)); } -static inline void cputime_to_timespec(const cputime_t cputime, - struct timespec *value) +static inline void cputime_to_timespec64(const cputime_t cputime, + struct timespec64 *value) { unsigned long long __cputime = (__force unsigned long long) cputime; value->tv_nsec = (__cputime % CPUTIME_PER_SEC) * NSEC_PER_USEC / CPUTIME_PER_USEC; diff --git a/include/asm-generic/cputime_jiffies.h b/include/asm-generic/cputime_jiffies.h index fe386fc..54e034c 100644 --- a/include/asm-generic/cputime_jiffies.h +++ b/include/asm-generic/cputime_jiffies.h @@ -44,12 +44,12 @@ typedef u64 __nocast cputime64_t; #define secs_to_cputime(sec) jiffies_to_cputime((sec) * HZ) /* - * Convert cputime to timespec and back. + * Convert cputime to timespec64 and back. */ -#define timespec_to_cputime(__val) \ - jiffies_to_cputime(timespec_to_jiffies(__val)) -#define cputime_to_timespec(__ct,__val) \ - jiffies_to_timespec(cputime_to_jiffies(__ct),__val) +#define timespec64_to_cputime(__val) \ + jiffies_to_cputime(timespec64_to_jiffies(__val)) +#define cputime_to_timespec64(__ct,__val) \ + jiffies_to_timespec64(cputime_to_jiffies(__ct),__val) /* * Convert cputime to timeval and back. diff --git a/include/asm-generic/cputime_nsecs.h b/include/asm-generic/cputime_nsecs.h index 0419485..c0cafc0 100644 --- a/include/asm-generic/cputime_nsecs.h +++ b/include/asm-generic/cputime_nsecs.h @@ -71,14 +71,14 @@ typedef u64 __nocast cputime64_t; (__force cputime_t)((__secs) * NSEC_PER_SEC) /* - * Convert cputime <-> timespec (nsec) + * Convert cputime <-> timespec64 (nsec) */ -static inline cputime_t timespec_to_cputime(const struct timespec *val) +static inline cputime_t timespec64_to_cputime(const struct timespec64 *val) { u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_nsec; return (__force cputime_t) ret; } -static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val) +static inline void cputime_to_timespec64(const cputime_t ct, struct timespec64 *val) { u32 rem; diff --git a/include/linux/cputime.h b/include/linux/cputime.h index f2eb2ee..cd638a0 100644 --- a/include/linux/cputime.h +++ b/include/linux/cputime.h @@ -13,4 +13,20 @@ usecs_to_cputime((__nsecs) / NSEC_PER_USEC) #endif +static inline cputime_t timespec_to_cputime(const struct timespec *ts) +{ + struct timespec64 ts64 = timespec_to_timespec64(*ts); + + return timespec64_to_cputime(&ts64); +} + +static inline void cputime_to_timespec(const cputime_t cputime, + struct timespec *value) +{ + struct timespec64 ts64; + + cputime_to_timespec64(cputime, &ts64); + *value = timespec64_to_timespec(ts64); +} + #endif /* __LINUX_CPUTIME_H */
The cputime_to_timespec() and timespec_to_cputime() functions are not year 2038 safe on 32bit systems due to that the struct timepsec will overflow in 2038 year. This patch introduces cputime_to_timespec64() and timespec64_to_cputime() functions which use struct timespec64. And converts arch specific implementations in arch/s390 and arch/powerpc. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> --- arch/powerpc/include/asm/cputime.h | 6 +++--- arch/s390/include/asm/cputime.h | 8 ++++---- include/asm-generic/cputime_jiffies.h | 10 +++++----- include/asm-generic/cputime_nsecs.h | 6 +++--- include/linux/cputime.h | 16 ++++++++++++++++ 5 files changed, 31 insertions(+), 15 deletions(-)