[tip:timers/core] posix-timers: Make posix_clocks immutable
From: tip-bot for Christoph Hellwig
Date: Fri May 26 2017 - 08:41:21 EST
Commit-ID: 82def146e8f511c37d8d8934202491483dd09ca9
Gitweb: http://git.kernel.org/tip/82def146e8f511c37d8d8934202491483dd09ca9
Author: Christoph Hellwig <hch@xxxxxx>
AuthorDate: Fri, 26 May 2017 12:03:11 +0300
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 26 May 2017 14:31:42 +0200
posix-timers: Make posix_clocks immutable
There are no more modular users providing a posix clock. The register
function is now pointless so the posix clock array can be initialized
statically at compile time and the array including the various k_clock
structs can be marked 'const'.
Inspired by changes in the Grsecurity patch set, but done proper.
[ tglx: Massaged changelog and fixed the POSIX_TIMER=n case ]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Mike Travis <mike.travis@xxxxxxx>
Cc: Dimitri Sivanich <sivanich@xxxxxxx>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@xxxxxx
---
include/linux/posix-timers.h | 9 +-
kernel/time/alarmtimer.c | 27 +++---
kernel/time/posix-clock.c | 2 +-
kernel/time/posix-cpu-timers.c | 34 +++-----
kernel/time/posix-timers.c | 191 +++++++++++++++++++----------------------
5 files changed, 120 insertions(+), 143 deletions(-)
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 8c1e43a..b313ef2 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -105,10 +105,11 @@ struct k_clock {
struct itimerspec64 *cur_setting);
};
-extern struct k_clock clock_posix_cpu;
-extern struct k_clock clock_posix_dynamic;
-
-void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
+extern const struct k_clock clock_posix_cpu;
+extern const struct k_clock clock_posix_dynamic;
+extern const struct k_clock clock_process;
+extern const struct k_clock clock_thread;
+extern const struct k_clock alarm_clock;
/* function to call to trigger timer event */
int posix_timer_event(struct k_itimer *timr, int si_private);
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 5cb5b00..7b5b7bf 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -488,7 +488,7 @@ u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
}
EXPORT_SYMBOL_GPL(alarm_forward_now);
-
+#ifdef CONFIG_POSIX_TIMERS
/**
* clock2alarm - helper that converts from clockid to alarmtypes
* @clockid: clockid.
@@ -846,6 +846,17 @@ out:
return ret;
}
+const struct k_clock alarm_clock = {
+ .clock_getres = alarm_clock_getres,
+ .clock_get = alarm_clock_get,
+ .timer_create = alarm_timer_create,
+ .timer_set = alarm_timer_set,
+ .timer_del = alarm_timer_del,
+ .timer_get = alarm_timer_get,
+ .nsleep = alarm_timer_nsleep,
+};
+#endif /* CONFIG_POSIX_TIMERS */
+
/* Suspend hook structures */
static const struct dev_pm_ops alarmtimer_pm_ops = {
@@ -871,23 +882,9 @@ static int __init alarmtimer_init(void)
struct platform_device *pdev;
int error = 0;
int i;
- struct k_clock alarm_clock = {
- .clock_getres = alarm_clock_getres,
- .clock_get = alarm_clock_get,
- .timer_create = alarm_timer_create,
- .timer_set = alarm_timer_set,
- .timer_del = alarm_timer_del,
- .timer_get = alarm_timer_get,
- .nsleep = alarm_timer_nsleep,
- };
alarmtimer_rtc_timer_init();
- if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
- posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
- posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
- }
-
/* Initialize alarm bases */
alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 31d588d..7e45300 100644
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -434,7 +434,7 @@ static int pc_timer_settime(struct k_itimer *kit, int flags,
return err;
}
-struct k_clock clock_posix_dynamic = {
+const struct k_clock clock_posix_dynamic = {
.clock_getres = pc_clock_getres,
.clock_set = pc_clock_settime,
.clock_get = pc_clock_gettime,
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 1370f06..1a522b3 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1413,7 +1413,7 @@ static int thread_cpu_timer_create(struct k_itimer *timer)
return posix_cpu_timer_create(timer);
}
-struct k_clock clock_posix_cpu = {
+const struct k_clock clock_posix_cpu = {
.clock_getres = posix_cpu_clock_getres,
.clock_set = posix_cpu_clock_set,
.clock_get = posix_cpu_clock_get,
@@ -1425,24 +1425,16 @@ struct k_clock clock_posix_cpu = {
.timer_get = posix_cpu_timer_get,
};
-static __init int init_posix_cpu_timers(void)
-{
- struct k_clock process = {
- .clock_getres = process_cpu_clock_getres,
- .clock_get = process_cpu_clock_get,
- .timer_create = process_cpu_timer_create,
- .nsleep = process_cpu_nsleep,
- .nsleep_restart = process_cpu_nsleep_restart,
- };
- struct k_clock thread = {
- .clock_getres = thread_cpu_clock_getres,
- .clock_get = thread_cpu_clock_get,
- .timer_create = thread_cpu_timer_create,
- };
-
- posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
- posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
+const struct k_clock clock_process = {
+ .clock_getres = process_cpu_clock_getres,
+ .clock_get = process_cpu_clock_get,
+ .timer_create = process_cpu_timer_create,
+ .nsleep = process_cpu_nsleep,
+ .nsleep_restart = process_cpu_nsleep_restart,
+};
- return 0;
-}
-__initcall(init_posix_cpu_timers);
+const struct k_clock clock_thread = {
+ .clock_getres = thread_cpu_clock_getres,
+ .clock_get = thread_cpu_clock_get,
+ .timer_create = thread_cpu_timer_create,
+};
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 4d7b2ce..0c0cccf 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -125,8 +125,6 @@ static DEFINE_SPINLOCK(hash_lock);
* which we beg off on and pass to do_sys_settimeofday().
*/
-static struct k_clock posix_clocks[MAX_CLOCKS];
-
/*
* These ones are defined below.
*/
@@ -280,74 +278,87 @@ static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
return 0;
}
+
+static const struct k_clock clock_realtime = {
+ .clock_getres = posix_get_hrtimer_res,
+ .clock_get = posix_clock_realtime_get,
+ .clock_set = posix_clock_realtime_set,
+ .clock_adj = posix_clock_realtime_adj,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+};
+
+static const struct k_clock clock_monotonic = {
+ .clock_getres = posix_get_hrtimer_res,
+ .clock_get = posix_ktime_get_ts,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+};
+
+static const struct k_clock clock_monotonic_raw = {
+ .clock_getres = posix_get_hrtimer_res,
+ .clock_get = posix_get_monotonic_raw,
+};
+
+static const struct k_clock clock_realtime_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_realtime_coarse,
+};
+
+static const struct k_clock clock_monotonic_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_monotonic_coarse,
+};
+
+static const struct k_clock clock_tai = {
+ .clock_getres = posix_get_hrtimer_res,
+ .clock_get = posix_get_tai,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+};
+
+static const struct k_clock clock_boottime = {
+ .clock_getres = posix_get_hrtimer_res,
+ .clock_get = posix_get_boottime,
+ .nsleep = common_nsleep,
+ .nsleep_restart = hrtimer_nanosleep_restart,
+ .timer_create = common_timer_create,
+ .timer_set = common_timer_set,
+ .timer_get = common_timer_get,
+ .timer_del = common_timer_del,
+};
+
+static const struct k_clock * const posix_clocks[] = {
+ [CLOCK_REALTIME] = &clock_realtime,
+ [CLOCK_MONOTONIC] = &clock_monotonic,
+ [CLOCK_PROCESS_CPUTIME_ID] = &clock_process,
+ [CLOCK_THREAD_CPUTIME_ID] = &clock_thread,
+ [CLOCK_MONOTONIC_RAW] = &clock_monotonic_raw,
+ [CLOCK_REALTIME_COARSE] = &clock_realtime_coarse,
+ [CLOCK_MONOTONIC_COARSE] = &clock_monotonic_coarse,
+ [CLOCK_BOOTTIME] = &clock_boottime,
+ [CLOCK_REALTIME_ALARM] = &alarm_clock,
+ [CLOCK_BOOTTIME_ALARM] = &alarm_clock,
+ [CLOCK_TAI] = &clock_tai,
+};
+
/*
* Initialize everything, well, just everything in Posix clocks/timers ;)
*/
static __init int init_posix_timers(void)
{
- struct k_clock clock_realtime = {
- .clock_getres = posix_get_hrtimer_res,
- .clock_get = posix_clock_realtime_get,
- .clock_set = posix_clock_realtime_set,
- .clock_adj = posix_clock_realtime_adj,
- .nsleep = common_nsleep,
- .nsleep_restart = hrtimer_nanosleep_restart,
- .timer_create = common_timer_create,
- .timer_set = common_timer_set,
- .timer_get = common_timer_get,
- .timer_del = common_timer_del,
- };
- struct k_clock clock_monotonic = {
- .clock_getres = posix_get_hrtimer_res,
- .clock_get = posix_ktime_get_ts,
- .nsleep = common_nsleep,
- .nsleep_restart = hrtimer_nanosleep_restart,
- .timer_create = common_timer_create,
- .timer_set = common_timer_set,
- .timer_get = common_timer_get,
- .timer_del = common_timer_del,
- };
- struct k_clock clock_monotonic_raw = {
- .clock_getres = posix_get_hrtimer_res,
- .clock_get = posix_get_monotonic_raw,
- };
- struct k_clock clock_realtime_coarse = {
- .clock_getres = posix_get_coarse_res,
- .clock_get = posix_get_realtime_coarse,
- };
- struct k_clock clock_monotonic_coarse = {
- .clock_getres = posix_get_coarse_res,
- .clock_get = posix_get_monotonic_coarse,
- };
- struct k_clock clock_tai = {
- .clock_getres = posix_get_hrtimer_res,
- .clock_get = posix_get_tai,
- .nsleep = common_nsleep,
- .nsleep_restart = hrtimer_nanosleep_restart,
- .timer_create = common_timer_create,
- .timer_set = common_timer_set,
- .timer_get = common_timer_get,
- .timer_del = common_timer_del,
- };
- struct k_clock clock_boottime = {
- .clock_getres = posix_get_hrtimer_res,
- .clock_get = posix_get_boottime,
- .nsleep = common_nsleep,
- .nsleep_restart = hrtimer_nanosleep_restart,
- .timer_create = common_timer_create,
- .timer_set = common_timer_set,
- .timer_get = common_timer_get,
- .timer_del = common_timer_del,
- };
-
- posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
- posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
- posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
- posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
- posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
- posix_timers_register_clock(CLOCK_BOOTTIME, &clock_boottime);
- posix_timers_register_clock(CLOCK_TAI, &clock_tai);
-
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
NULL);
@@ -521,30 +532,6 @@ static struct pid *good_sigevent(sigevent_t * event)
return task_pid(rtn);
}
-void posix_timers_register_clock(const clockid_t clock_id,
- struct k_clock *new_clock)
-{
- if ((unsigned) clock_id >= MAX_CLOCKS) {
- printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
- clock_id);
- return;
- }
-
- if (!new_clock->clock_get) {
- printk(KERN_WARNING "POSIX clock id %d lacks clock_get()\n",
- clock_id);
- return;
- }
- if (!new_clock->clock_getres) {
- printk(KERN_WARNING "POSIX clock id %d lacks clock_getres()\n",
- clock_id);
- return;
- }
-
- posix_clocks[clock_id] = *new_clock;
-}
-EXPORT_SYMBOL_GPL(posix_timers_register_clock);
-
static struct k_itimer * alloc_posix_timer(void)
{
struct k_itimer *tmr;
@@ -581,15 +568,15 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
call_rcu(&tmr->it.rcu, k_itimer_rcu_free);
}
-static struct k_clock *clockid_to_kclock(const clockid_t id)
+static const struct k_clock *clockid_to_kclock(const clockid_t id)
{
if (id < 0)
return (id & CLOCKFD_MASK) == CLOCKFD ?
&clock_posix_dynamic : &clock_posix_cpu;
- if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
+ if (id >= ARRAY_SIZE(posix_clocks) || !posix_clocks[id])
return NULL;
- return &posix_clocks[id];
+ return posix_clocks[id];
}
static int common_timer_create(struct k_itimer *new_timer)
@@ -604,7 +591,7 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
struct sigevent __user *, timer_event_spec,
timer_t __user *, created_timer_id)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct k_itimer *new_timer;
int error, new_timer_id;
sigevent_t event;
@@ -781,7 +768,7 @@ SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
struct itimerspec64 cur_setting64;
struct itimerspec cur_setting;
struct k_itimer *timr;
- struct k_clock *kc;
+ const struct k_clock *kc;
unsigned long flags;
int ret = 0;
@@ -890,7 +877,7 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
struct itimerspec new_spec, old_spec;
struct k_itimer *timr;
unsigned long flag;
- struct k_clock *kc;
+ const struct k_clock *kc;
int error = 0;
if (!new_setting)
@@ -939,7 +926,7 @@ static int common_timer_del(struct k_itimer *timer)
static inline int timer_delete_hook(struct k_itimer *timer)
{
- struct k_clock *kc = clockid_to_kclock(timer->it_clock);
+ const struct k_clock *kc = clockid_to_kclock(timer->it_clock);
if (WARN_ON_ONCE(!kc || !kc->timer_del))
return -EINVAL;
@@ -1018,7 +1005,7 @@ void exit_itimers(struct signal_struct *sig)
SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
const struct timespec __user *, tp)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct timespec64 new_tp64;
struct timespec new_tp;
@@ -1035,7 +1022,7 @@ SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
struct timespec __user *,tp)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct timespec64 kernel_tp64;
struct timespec kernel_tp;
int error;
@@ -1055,7 +1042,7 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
struct timex __user *, utx)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct timex ktx;
int err;
@@ -1078,7 +1065,7 @@ SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
struct timespec __user *, tp)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct timespec64 rtn_tp64;
struct timespec rtn_tp;
int error;
@@ -1110,7 +1097,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
const struct timespec __user *, rqtp,
struct timespec __user *, rmtp)
{
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
struct timespec64 t64;
struct timespec t;
@@ -1136,7 +1123,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
long clock_nanosleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->nanosleep.clockid;
- struct k_clock *kc = clockid_to_kclock(which_clock);
+ const struct k_clock *kc = clockid_to_kclock(which_clock);
if (WARN_ON_ONCE(!kc || !kc->nsleep_restart))
return -EINVAL;