From 09a9982016499daeb3fbee5ac8d87797310a565a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 19 Nov 2015 11:43:09 +0100 Subject: timekeeping: Lift clocksource cacheline restriction We cache all hotpath members of a clocksource in the time keeper core. So there is no requirement in general to cache line align struct clocksource. Remove the enforces alignment. That allows users which need to wrap struct clocksource into their own struct to align the struct without getting extra padding. Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Russell King - ARM Linux Cc: Marc Gonzalez Cc: Daniel Lezcano Cc: Mans Rullgard Cc: Viresh Kumar Cc: Nicolas Pitre Cc: Tony Lindgren Cc: Sebastian Frias Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1511191209000.3898@nanos --- include/linux/clocksource.h | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 7784b597e959..6013021a3b39 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -62,12 +62,18 @@ struct module; * @suspend: suspend function for the clocksource, if necessary * @resume: resume function for the clocksource, if necessary * @owner: module reference, must be set by clocksource in modules + * + * Note: This struct is not used in hotpathes of the timekeeping code + * because the timekeeper caches the hot path fields in its own data + * structure, so no line cache alignment is required, + * + * The pointer to the clocksource itself is handed to the read + * callback. If you need extra information there you can wrap struct + * clocksource into your own struct. Depending on the amount of + * information you need you should consider to cache line align that + * structure. */ struct clocksource { - /* - * Hotpath data, fits in a single cache line when the - * clocksource itself is cacheline aligned. - */ cycle_t (*read)(struct clocksource *cs); cycle_t mask; u32 mult; @@ -95,7 +101,7 @@ struct clocksource { cycle_t wd_last; #endif struct module *owner; -} ____cacheline_aligned; +}; /* * Clock source flags bits:: -- cgit v1.3-6-gb490 From 37cf4dc3370fbca0344e23bb96446eb2c3548ba7 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 3 Dec 2015 22:09:31 -0500 Subject: time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow For adjtimex()'s ADJ_SETOFFSET, make sure the tv_usec value is sane. We might multiply them later which can cause an overflow and undefined behavior. This patch introduces new helper functions to simplify the checking code and adds comments to clarify Orginally this patch was by Sasha Levin, but I've basically rewritten it, so he should get credit for finding the issue and I should get the blame for any mistakes made since. Also, credit to Richard Cochran for the phrasing used in the comment for what is considered valid here. Cc: Sasha Levin Cc: Richard Cochran Cc: Thomas Gleixner Reported-by: Sasha Levin Signed-off-by: John Stultz --- include/linux/time.h | 26 ++++++++++++++++++++++++++ kernel/time/ntp.c | 10 ++++++++-- kernel/time/timekeeping.c | 2 +- 3 files changed, 35 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/time.h b/include/linux/time.h index beebe3a02d43..297f09f23896 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -125,6 +125,32 @@ static inline bool timeval_valid(const struct timeval *tv) extern struct timespec timespec_trunc(struct timespec t, unsigned gran); +/* + * Validates if a timespec/timeval used to inject a time offset is valid. + * Offsets can be postive or negative. The value of the timeval/timespec + * is the sum of its fields, but *NOTE*: the field tv_usec/tv_nsec must + * always be non-negative. + */ +static inline bool timeval_inject_offset_valid(const struct timeval *tv) +{ + /* We don't check the tv_sec as it can be positive or negative */ + + /* Can't have more microseconds then a second */ + if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC) + return false; + return true; +} + +static inline bool timespec_inject_offset_valid(const struct timespec *ts) +{ + /* We don't check the tv_sec as it can be positive or negative */ + + /* Can't have more nanoseconds then a second */ + if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC) + return false; + return true; +} + #define CURRENT_TIME (current_kernel_time()) #define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 }) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 125fc0342355..4073c9550af9 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -676,8 +676,14 @@ int ntp_validate_timex(struct timex *txc) return -EINVAL; } - if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) - return -EPERM; + if (txc->modes & ADJ_SETOFFSET) { + /* In order to inject time, you gotta be super-user! */ + if (!capable(CAP_SYS_TIME)) + return -EPERM; + + if (!timeval_inject_offset_valid(&txc->time)) + return -EINVAL; + } /* * Check for potential multiplication overflows that can diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 99188ee5d9d0..d9249daf14ba 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -958,7 +958,7 @@ int timekeeping_inject_offset(struct timespec *ts) struct timespec64 ts64, tmp; int ret = 0; - if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) + if (!timespec_inject_offset_valid(ts)) return -EINVAL; ts64 = timespec_to_timespec64(*ts); -- cgit v1.3-6-gb490 From 364eba4b3a58a3e9af5a1355f4131a58cd1f3b8d Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Thu, 29 Oct 2015 18:33:47 +0100 Subject: time: Define dummy functions for the generic sched clock When we try to compile a clocksource driver with the COMPILE_TEST option, we can't select the GENERIC_SCHED_CLOCK because the sched_clock() symbol will be duplicated with the one defined for the x86. In order to fix that, we don't select the GENERIC_SCHED_CLOCK in the driver Kconfig's file but we define some empty functions for the different symbols in order to prevent the unresolved ones. This patch fixes the COMPILE_TEST option for the compile test coverage for the clocksource drivers. Without this patch, we can't add the COMPILE_TEST option for the clocksource drivers using the GENERIC_SCHED_CLOCK. Signed-off-by: Daniel Lezcano --- include/linux/sched_clock.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched_clock.h b/include/linux/sched_clock.h index efa931c5cef1..411b52e424e1 100644 --- a/include/linux/sched_clock.h +++ b/include/linux/sched_clock.h @@ -10,11 +10,17 @@ #ifdef CONFIG_GENERIC_SCHED_CLOCK extern void sched_clock_postinit(void); -#else -static inline void sched_clock_postinit(void) { } -#endif extern void sched_clock_register(u64 (*read)(void), int bits, unsigned long rate); +#else +static inline void sched_clock_postinit(void) { } + +static inline void sched_clock_register(u64 (*read)(void), int bits, + unsigned long rate) +{ + ; +} +#endif #endif -- cgit v1.3-6-gb490