From 2c620ff93d9fbd5d644760d4c21d389078ec1080 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Mon, 2 Jul 2018 22:44:20 -0700 Subject: time: Add struct __kernel_timex struct timex uses struct timeval internally. struct timeval is not y2038 safe. Introduce a new UAPI type struct __kernel_timex that is y2038 safe. struct __kernel_timex uses a timeval type that is similar to struct __kernel_timespec which preserves the same structure size across 32 bit and 64 bit ABIs. struct __kernel_timex also restructures other members of the structure to make the structure the same on 64 bit and 32 bit architectures. Note that struct __kernel_timex is the same as struct timex on a 64 bit architecture. The above solution is similar to other new y2038 syscalls that are being introduced: both 32 bit and 64 bit ABIs have a common entry, and the compat entry supports the old 32 bit syscall interface. Alternatives considered were: 1. Add new time type to struct timex that makes use of padded bits. This time type could be based on the struct __kernel_timespec. modes will use a flag to notify which time structure should be used internally. This needs some application level changes on both 64 bit and 32 bit architectures. Although 64 bit machines could continue to use the older timeval structure without any changes. 2. Add a new u8 type to struct timex that makes use of padded bits. This can be used to save higher order tv_sec bits. modes will use a flag to notify presence of such a type. This will need some application level changes on 32 bit architectures. 3. Add a new compat_timex structure that differs in only the size of the time type; keep rest of struct timex the same. This requires extra syscalls to manage all 3 cases on 64 bit architectures. This will not need any application level changes but will add more complexity from kernel side. Signed-off-by: Deepa Dinamani Signed-off-by: Arnd Bergmann --- include/uapi/linux/timex.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/timex.h b/include/uapi/linux/timex.h index 92685d826444..a1c6b73016a5 100644 --- a/include/uapi/linux/timex.h +++ b/include/uapi/linux/timex.h @@ -92,6 +92,47 @@ struct timex { int :32; int :32; int :32; }; +struct __kernel_timex_timeval { + __kernel_time64_t tv_sec; + long long tv_usec; +}; + +#ifndef __kernel_timex +struct __kernel_timex { + unsigned int modes; /* mode selector */ + int :32; /* pad */ + long long offset; /* time offset (usec) */ + long long freq; /* frequency offset (scaled ppm) */ + long long maxerror;/* maximum error (usec) */ + long long esterror;/* estimated error (usec) */ + int status; /* clock command/status */ + int :32; /* pad */ + long long constant;/* pll time constant */ + long long precision;/* clock precision (usec) (read only) */ + long long tolerance;/* clock frequency tolerance (ppm) + * (read only) + */ + struct __kernel_timex_timeval time; /* (read only, except for ADJ_SETOFFSET) */ + long long tick; /* (modified) usecs between clock ticks */ + + long long ppsfreq;/* pps frequency (scaled ppm) (ro) */ + long long jitter; /* pps jitter (us) (ro) */ + int shift; /* interval duration (s) (shift) (ro) */ + int :32; /* pad */ + long long stabil; /* pps stability (scaled ppm) (ro) */ + long long jitcnt; /* jitter limit exceeded (ro) */ + long long calcnt; /* calibration intervals (ro) */ + long long errcnt; /* calibration errors (ro) */ + long long stbcnt; /* stability limit exceeded (ro) */ + + int tai; /* TAI offset (ro) */ + + int :32; int :32; int :32; int :32; + int :32; int :32; int :32; int :32; + int :32; int :32; int :32; +}; +#endif + /* * Mode codes (timex.mode) */ -- cgit v1.2.3 From c70a772fda11570ebddecbce1543a3fda008db4a Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 7 Jan 2019 00:00:34 +0100 Subject: y2038: remove struct definition redirects We now use 64-bit time_t on all architectures, so the __kernel_timex, __kernel_timeval and __kernel_timespec redirects can be removed after having served their purpose. This makes it all much less confusing, as the __kernel_* types now always refer to the same layout based on 64-bit time_t across all 32-bit and 64-bit architectures. Signed-off-by: Arnd Bergmann --- include/uapi/linux/time.h | 4 ---- include/uapi/linux/timex.h | 2 -- 2 files changed, 6 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h index 6b56a2208be7..b03f8717c312 100644 --- a/include/uapi/linux/time.h +++ b/include/uapi/linux/time.h @@ -42,19 +42,15 @@ struct itimerval { struct timeval it_value; /* current value */ }; -#ifndef __kernel_timespec struct __kernel_timespec { __kernel_time64_t tv_sec; /* seconds */ long long tv_nsec; /* nanoseconds */ }; -#endif -#ifndef __kernel_itimerspec struct __kernel_itimerspec { struct __kernel_timespec it_interval; /* timer period */ struct __kernel_timespec it_value; /* timer expiration */ }; -#endif /* * legacy timeval structure, only embedded in structures that diff --git a/include/uapi/linux/timex.h b/include/uapi/linux/timex.h index a1c6b73016a5..9f517f9010bb 100644 --- a/include/uapi/linux/timex.h +++ b/include/uapi/linux/timex.h @@ -97,7 +97,6 @@ struct __kernel_timex_timeval { long long tv_usec; }; -#ifndef __kernel_timex struct __kernel_timex { unsigned int modes; /* mode selector */ int :32; /* pad */ @@ -131,7 +130,6 @@ struct __kernel_timex { int :32; int :32; int :32; int :32; int :32; int :32; int :32; }; -#endif /* * Mode codes (timex.mode) -- cgit v1.2.3