Re: [PATCH 1/8] posix clocks: introduce a syscall for clock tuning.

From: Benjamin Herrenschmidt
Date: Thu Sep 23 2010 - 18:05:34 EST

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In reply to: john stultz: "Re: [PATCH 1/8] posix clocks: introduce a syscall for clock tuning."
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On Thu, 2010-09-23 at 19:31 +0200, Richard Cochran wrote:
> A new syscall is introduced that allows tuning of a POSIX clock. The
> syscall is implemented for four architectures: arm, blackfin, powerpc,
> and x86.
>
> The new syscall, clock_adjtime, takes two parameters, the clock ID,
> and a pointer to a struct timex. The semantics of the timex struct
> have been expanded by one additional mode flag, which allows an
> absolute offset correction. When specificied, the clock offset is
> immediately corrected by adding the given time value to the current
> time value.

Any reason why you CC'ed device-tree discuss ?

This list is getting way too much unrelated stuff, which I find
annoying, it would be nice if we were all a bit more careful here with
our CC lists.

Cheers,
Ben.

> Signed-off-by: Richard Cochran <richard.cochran@xxxxxxxxxx>
> ---
> arch/arm/include/asm/unistd.h | 1 +
> arch/arm/kernel/calls.S | 1 +
> arch/blackfin/include/asm/unistd.h | 3 +-
> arch/blackfin/mach-common/entry.S | 1 +
> arch/powerpc/include/asm/systbl.h | 1 +
> arch/powerpc/include/asm/unistd.h | 3 +-
> arch/x86/ia32/ia32entry.S | 1 +
> arch/x86/include/asm/unistd_32.h | 3 +-
> arch/x86/include/asm/unistd_64.h | 2 +
> arch/x86/kernel/syscall_table_32.S | 1 +
> include/linux/posix-timers.h | 3 +
> include/linux/syscalls.h | 2 +
> include/linux/timex.h | 3 +-
> kernel/compat.c | 136 +++++++++++++++++++++++-------------
> kernel/posix-cpu-timers.c | 4 +
> kernel/posix-timers.c | 17 +++++
> 16 files changed, 130 insertions(+), 52 deletions(-)
>
> diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
> index c891eb7..f58d881 100644
> --- a/arch/arm/include/asm/unistd.h
> +++ b/arch/arm/include/asm/unistd.h
> @@ -396,6 +396,7 @@
> #define __NR_fanotify_init (__NR_SYSCALL_BASE+367)
> #define __NR_fanotify_mark (__NR_SYSCALL_BASE+368)
> #define __NR_prlimit64 (__NR_SYSCALL_BASE+369)
> +#define __NR_clock_adjtime (__NR_SYSCALL_BASE+370)
>
> /*
> * The following SWIs are ARM private.
> diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
> index 5c26ecc..430de4c 100644
> --- a/arch/arm/kernel/calls.S
> +++ b/arch/arm/kernel/calls.S
> @@ -379,6 +379,7 @@
> CALL(sys_fanotify_init)
> CALL(sys_fanotify_mark)
> CALL(sys_prlimit64)
> +/* 370 */ CALL(sys_clock_adjtime)
> #ifndef syscalls_counted
> .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
> #define syscalls_counted
> diff --git a/arch/blackfin/include/asm/unistd.h b/arch/blackfin/include/asm/unistd.h
> index 14fcd25..79ad99b 100644
> --- a/arch/blackfin/include/asm/unistd.h
> +++ b/arch/blackfin/include/asm/unistd.h
> @@ -392,8 +392,9 @@
> #define __NR_fanotify_init 371
> #define __NR_fanotify_mark 372
> #define __NR_prlimit64 373
> +#define __NR_clock_adjtime 374
>
> -#define __NR_syscall 374
> +#define __NR_syscall 375
> #define NR_syscalls __NR_syscall
>
> /* Old optional stuff no one actually uses */
> diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
> index af1bffa..ee68730 100644
> --- a/arch/blackfin/mach-common/entry.S
> +++ b/arch/blackfin/mach-common/entry.S
> @@ -1631,6 +1631,7 @@ ENTRY(_sys_call_table)
> .long _sys_fanotify_init
> .long _sys_fanotify_mark
> .long _sys_prlimit64
> + .long _sys_clock_adjtime
>
> .rept NR_syscalls-(.-_sys_call_table)/4
> .long _sys_ni_syscall
> diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
> index 3d21266..2485d8f 100644
> --- a/arch/powerpc/include/asm/systbl.h
> +++ b/arch/powerpc/include/asm/systbl.h
> @@ -329,3 +329,4 @@ COMPAT_SYS(rt_tgsigqueueinfo)
> SYSCALL(fanotify_init)
> COMPAT_SYS(fanotify_mark)
> SYSCALL_SPU(prlimit64)
> +COMPAT_SYS_SPU(clock_adjtime)
> diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
> index 597e6f9..85d5067 100644
> --- a/arch/powerpc/include/asm/unistd.h
> +++ b/arch/powerpc/include/asm/unistd.h
> @@ -348,10 +348,11 @@
> #define __NR_fanotify_init 323
> #define __NR_fanotify_mark 324
> #define __NR_prlimit64 325
> +#define __NR_clock_adjtime 326
>
> #ifdef __KERNEL__
>
> -#define __NR_syscalls 326
> +#define __NR_syscalls 327
>
> #define __NR__exit __NR_exit
> #define NR_syscalls __NR_syscalls
> diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
> index 518bb99..0ed7896 100644
> --- a/arch/x86/ia32/ia32entry.S
> +++ b/arch/x86/ia32/ia32entry.S
> @@ -851,4 +851,5 @@ ia32_sys_call_table:
> .quad sys_fanotify_init
> .quad sys32_fanotify_mark
> .quad sys_prlimit64 /* 340 */
> + .quad compat_sys_clock_adjtime
> ia32_syscall_end:
> diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
> index b766a5e..b6f73f1 100644
> --- a/arch/x86/include/asm/unistd_32.h
> +++ b/arch/x86/include/asm/unistd_32.h
> @@ -346,10 +346,11 @@
> #define __NR_fanotify_init 338
> #define __NR_fanotify_mark 339
> #define __NR_prlimit64 340
> +#define __NR_clock_adjtime 341
>
> #ifdef __KERNEL__
>
> -#define NR_syscalls 341
> +#define NR_syscalls 342
>
> #define __ARCH_WANT_IPC_PARSE_VERSION
> #define __ARCH_WANT_OLD_READDIR
> diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
> index 363e9b8..5ee3085 100644
> --- a/arch/x86/include/asm/unistd_64.h
> +++ b/arch/x86/include/asm/unistd_64.h
> @@ -669,6 +669,8 @@ __SYSCALL(__NR_fanotify_init, sys_fanotify_init)
> __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
> #define __NR_prlimit64 302
> __SYSCALL(__NR_prlimit64, sys_prlimit64)
> +#define __NR_clock_adjtime 303
> +__SYSCALL(__NR_clock_adjtime, sys_clock_adjtime)
>
> #ifndef __NO_STUBS
> #define __ARCH_WANT_OLD_READDIR
> diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
> index b35786d..68c7b9a 100644
> --- a/arch/x86/kernel/syscall_table_32.S
> +++ b/arch/x86/kernel/syscall_table_32.S
> @@ -340,3 +340,4 @@ ENTRY(sys_call_table)
> .long sys_fanotify_init
> .long sys_fanotify_mark
> .long sys_prlimit64 /* 340 */
> + .long sys_clock_adjtime
> diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
> index 3e23844..abf61cc 100644
> --- a/include/linux/posix-timers.h
> +++ b/include/linux/posix-timers.h
> @@ -4,6 +4,7 @@
> #include <linux/spinlock.h>
> #include <linux/list.h>
> #include <linux/sched.h>
> +#include <linux/timex.h>
>
> union cpu_time_count {
> cputime_t cpu;
> @@ -71,6 +72,7 @@ struct k_clock {
> int (*clock_getres) (const clockid_t which_clock, struct timespec *tp);
> int (*clock_set) (const clockid_t which_clock, struct timespec * tp);
> int (*clock_get) (const clockid_t which_clock, struct timespec * tp);
> + int (*clock_adj) (const clockid_t which_clock, struct timex *tx);
> int (*timer_create) (struct k_itimer *timer);
> int (*nsleep) (const clockid_t which_clock, int flags,
> struct timespec *, struct timespec __user *);
> @@ -97,6 +99,7 @@ int posix_timer_event(struct k_itimer *timr, int si_private);
> int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *ts);
> int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *ts);
> int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *ts);
> +int posix_cpu_clock_adj(const clockid_t which_clock, struct timex *tx);
> int posix_cpu_timer_create(struct k_itimer *timer);
> int posix_cpu_nsleep(const clockid_t which_clock, int flags,
> struct timespec *rqtp, struct timespec __user *rmtp);
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index e6319d1..0b24775 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -313,6 +313,8 @@ asmlinkage long sys_clock_settime(clockid_t which_clock,
> const struct timespec __user *tp);
> asmlinkage long sys_clock_gettime(clockid_t which_clock,
> struct timespec __user *tp);
> +asmlinkage long sys_clock_adjtime(clockid_t which_clock,
> + struct timex __user *tx);
> asmlinkage long sys_clock_getres(clockid_t which_clock,
> struct timespec __user *tp);
> asmlinkage long sys_clock_nanosleep(clockid_t which_clock, int flags,
> diff --git a/include/linux/timex.h b/include/linux/timex.h
> index 32d852f..82d4b24 100644
> --- a/include/linux/timex.h
> +++ b/include/linux/timex.h
> @@ -73,7 +73,7 @@ struct timex {
> long tolerance; /* clock frequency tolerance (ppm)
> * (read only)
> */
> - struct timeval time; /* (read only) */
> + struct timeval time; /* (read only, except for ADJ_SETOFFSET) */
> long tick; /* (modified) usecs between clock ticks */
>
> long ppsfreq; /* pps frequency (scaled ppm) (ro) */
> @@ -101,6 +101,7 @@ struct timex {
> #define ADJ_ESTERROR 0x0008 /* estimated time error */
> #define ADJ_STATUS 0x0010 /* clock status */
> #define ADJ_TIMECONST 0x0020 /* pll time constant */
> +#define ADJ_SETOFFSET 0x0040 /* add 'time' to current time */
> #define ADJ_TAI 0x0080 /* set TAI offset */
> #define ADJ_MICRO 0x1000 /* select microsecond resolution */
> #define ADJ_NANO 0x2000 /* select nanosecond resolution */
> diff --git a/kernel/compat.c b/kernel/compat.c
> index c9e2ec0..38b1d2c 100644
> --- a/kernel/compat.c
> +++ b/kernel/compat.c
> @@ -52,6 +52,64 @@ static int compat_put_timeval(struct compat_timeval __user *o,
> put_user(i->tv_usec, &o->tv_usec)) ? -EFAULT : 0;
> }
>
> +static int compat_get_timex(struct timex *txc, struct compat_timex __user *utp)
> +{
> + memset(txc, 0, sizeof(struct timex));
> +
> + if (!access_ok(VERIFY_READ, utp, sizeof(struct compat_timex)) ||
> + __get_user(txc->modes, &utp->modes) ||
> + __get_user(txc->offset, &utp->offset) ||
> + __get_user(txc->freq, &utp->freq) ||
> + __get_user(txc->maxerror, &utp->maxerror) ||
> + __get_user(txc->esterror, &utp->esterror) ||
> + __get_user(txc->status, &utp->status) ||
> + __get_user(txc->constant, &utp->constant) ||
> + __get_user(txc->precision, &utp->precision) ||
> + __get_user(txc->tolerance, &utp->tolerance) ||
> + __get_user(txc->time.tv_sec, &utp->time.tv_sec) ||
> + __get_user(txc->time.tv_usec, &utp->time.tv_usec) ||
> + __get_user(txc->tick, &utp->tick) ||
> + __get_user(txc->ppsfreq, &utp->ppsfreq) ||
> + __get_user(txc->jitter, &utp->jitter) ||
> + __get_user(txc->shift, &utp->shift) ||
> + __get_user(txc->stabil, &utp->stabil) ||
> + __get_user(txc->jitcnt, &utp->jitcnt) ||
> + __get_user(txc->calcnt, &utp->calcnt) ||
> + __get_user(txc->errcnt, &utp->errcnt) ||
> + __get_user(txc->stbcnt, &utp->stbcnt))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int compat_put_timex(struct compat_timex __user *utp, struct timex *txc)
> +{
> + if (!access_ok(VERIFY_WRITE, utp, sizeof(struct compat_timex)) ||
> + __put_user(txc->modes, &utp->modes) ||
> + __put_user(txc->offset, &utp->offset) ||
> + __put_user(txc->freq, &utp->freq) ||
> + __put_user(txc->maxerror, &utp->maxerror) ||
> + __put_user(txc->esterror, &utp->esterror) ||
> + __put_user(txc->status, &utp->status) ||
> + __put_user(txc->constant, &utp->constant) ||
> + __put_user(txc->precision, &utp->precision) ||
> + __put_user(txc->tolerance, &utp->tolerance) ||
> + __put_user(txc->time.tv_sec, &utp->time.tv_sec) ||
> + __put_user(txc->time.tv_usec, &utp->time.tv_usec) ||
> + __put_user(txc->tick, &utp->tick) ||
> + __put_user(txc->ppsfreq, &utp->ppsfreq) ||
> + __put_user(txc->jitter, &utp->jitter) ||
> + __put_user(txc->shift, &utp->shift) ||
> + __put_user(txc->stabil, &utp->stabil) ||
> + __put_user(txc->jitcnt, &utp->jitcnt) ||
> + __put_user(txc->calcnt, &utp->calcnt) ||
> + __put_user(txc->errcnt, &utp->errcnt) ||
> + __put_user(txc->stbcnt, &utp->stbcnt) ||
> + __put_user(txc->tai, &utp->tai))
> + return -EFAULT;
> + return 0;
> +}
> +
> asmlinkage long compat_sys_gettimeofday(struct compat_timeval __user *tv,
> struct timezone __user *tz)
> {
> @@ -617,6 +675,29 @@ long compat_sys_clock_gettime(clockid_t which_clock,
> return err;
> }
>
> +long compat_sys_clock_adjtime(clockid_t which_clock,
> + struct compat_timex __user *utp)
> +{
> + struct timex txc;
> + mm_segment_t oldfs;
> + int err, ret;
> +
> + err = compat_get_timex(&txc, utp);
> + if (err)
> + return err;
> +
> + oldfs = get_fs();
> + set_fs(KERNEL_DS);
> + ret = sys_clock_adjtime(which_clock, (struct timex __user *) &txc);
> + set_fs(oldfs);
> +
> + err = compat_put_timex(utp, &txc);
> + if (err)
> + return err;
> +
> + return ret;
> +}
> +
> long compat_sys_clock_getres(clockid_t which_clock,
> struct compat_timespec __user *tp)
> {
> @@ -951,58 +1032,17 @@ asmlinkage long compat_sys_rt_sigsuspend(compat_sigset_t __user *unewset, compat
> asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp)
> {
> struct timex txc;
> - int ret;
> -
> - memset(&txc, 0, sizeof(struct timex));
> + int err, ret;
>
> - if (!access_ok(VERIFY_READ, utp, sizeof(struct compat_timex)) ||
> - __get_user(txc.modes, &utp->modes) ||
> - __get_user(txc.offset, &utp->offset) ||
> - __get_user(txc.freq, &utp->freq) ||
> - __get_user(txc.maxerror, &utp->maxerror) ||
> - __get_user(txc.esterror, &utp->esterror) ||
> - __get_user(txc.status, &utp->status) ||
> - __get_user(txc.constant, &utp->constant) ||
> - __get_user(txc.precision, &utp->precision) ||
> - __get_user(txc.tolerance, &utp->tolerance) ||
> - __get_user(txc.time.tv_sec, &utp->time.tv_sec) ||
> - __get_user(txc.time.tv_usec, &utp->time.tv_usec) ||
> - __get_user(txc.tick, &utp->tick) ||
> - __get_user(txc.ppsfreq, &utp->ppsfreq) ||
> - __get_user(txc.jitter, &utp->jitter) ||
> - __get_user(txc.shift, &utp->shift) ||
> - __get_user(txc.stabil, &utp->stabil) ||
> - __get_user(txc.jitcnt, &utp->jitcnt) ||
> - __get_user(txc.calcnt, &utp->calcnt) ||
> - __get_user(txc.errcnt, &utp->errcnt) ||
> - __get_user(txc.stbcnt, &utp->stbcnt))
> - return -EFAULT;
> + err = compat_get_timex(&txc, utp);
> + if (err)
> + return err;
>
> ret = do_adjtimex(&txc);
>
> - if (!access_ok(VERIFY_WRITE, utp, sizeof(struct compat_timex)) ||
> - __put_user(txc.modes, &utp->modes) ||
> - __put_user(txc.offset, &utp->offset) ||
> - __put_user(txc.freq, &utp->freq) ||
> - __put_user(txc.maxerror, &utp->maxerror) ||
> - __put_user(txc.esterror, &utp->esterror) ||
> - __put_user(txc.status, &utp->status) ||
> - __put_user(txc.constant, &utp->constant) ||
> - __put_user(txc.precision, &utp->precision) ||
> - __put_user(txc.tolerance, &utp->tolerance) ||
> - __put_user(txc.time.tv_sec, &utp->time.tv_sec) ||
> - __put_user(txc.time.tv_usec, &utp->time.tv_usec) ||
> - __put_user(txc.tick, &utp->tick) ||
> - __put_user(txc.ppsfreq, &utp->ppsfreq) ||
> - __put_user(txc.jitter, &utp->jitter) ||
> - __put_user(txc.shift, &utp->shift) ||
> - __put_user(txc.stabil, &utp->stabil) ||
> - __put_user(txc.jitcnt, &utp->jitcnt) ||
> - __put_user(txc.calcnt, &utp->calcnt) ||
> - __put_user(txc.errcnt, &utp->errcnt) ||
> - __put_user(txc.stbcnt, &utp->stbcnt) ||
> - __put_user(txc.tai, &utp->tai))
> - ret = -EFAULT;
> + err = compat_put_timex(utp, &txc);
> + if (err)
> + return err;
>
> return ret;
> }
> diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
> index 6842eeb..e1c2e7b 100644
> --- a/kernel/posix-cpu-timers.c
> +++ b/kernel/posix-cpu-timers.c
> @@ -207,6 +207,10 @@ int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
> return error;
> }
>
> +int posix_cpu_clock_adj(const clockid_t which_clock, struct timex *tx)
> +{
> + return -EOPNOTSUPP;
> +}
>
> /*
> * Sample a per-thread clock for the given task.
> diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
> index 9ca4973..446b566 100644
> --- a/kernel/posix-timers.c
> +++ b/kernel/posix-timers.c
> @@ -197,6 +197,14 @@ static int common_timer_create(struct k_itimer *new_timer)
> return 0;
> }
>
> +static inline int common_clock_adj(const clockid_t which_clock, struct timex *t)
> +{
> + if (CLOCK_REALTIME == which_clock)
> + return do_adjtimex(t);
> + else
> + return -EOPNOTSUPP;
> +}
> +
> static int no_timer_create(struct k_itimer *new_timer)
> {
> return -EOPNOTSUPP;
> @@ -969,6 +977,15 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
>
> }
>
> +SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
> + struct timex __user *, tx)
> +{
> + if (invalid_clockid(which_clock))
> + return -EINVAL;
> +
> + return CLOCK_DISPATCH(which_clock, clock_adj, (which_clock, tx));
> +}
> +
> SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
> struct timespec __user *, tp)
> {

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Next message: Randy Dunlap: "Re: [BUG 2.6.36-rc5] of_i2c.ko <-> i2c-core.ko dependency loop"
Previous message: Haiyang Zhang: "[PATCH 1/1] Rename camel case variables in channel.c (updated)"
In reply to: john stultz: "Re: [PATCH 1/8] posix clocks: introduce a syscall for clock tuning."
Next in thread: Thomas Gleixner: "Re: [PATCH 1/8] posix clocks: introduce a syscall for clocktuning."
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