[PATCH] kernel: mark all struct k_clock instances const
From: Christoph Hellwig
Date: Mon May 15 2017 - 16:32:22 EST
And keep a pointer to it instead of a copy in the posix_clocks array.
Based on similar changes in the Grsecurity patchset, but redone from
scratch including a few tweaks.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/char/mmtimer.c | 4 +-
include/linux/posix-timers.h | 7 +-
kernel/time/alarmtimer.c | 19 +++---
kernel/time/posix-clock.c | 2 +-
kernel/time/posix-cpu-timers.c | 29 ++++----
kernel/time/posix-timers.c | 150 ++++++++++++++++++++++-------------------
6 files changed, 111 insertions(+), 100 deletions(-)
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index 0e7fcb04f01e..e501403dd860 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -53,7 +53,7 @@ MODULE_LICENSE("GPL");
#define RTC_BITS 55 /* 55 bits for this implementation */
-static struct k_clock sgi_clock;
+static const struct k_clock sgi_clock;
extern unsigned long sn_rtc_cycles_per_second;
@@ -772,7 +772,7 @@ static int sgi_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
return 0;
}
-static struct k_clock sgi_clock = {
+static const struct k_clock sgi_clock = {
.clock_set = sgi_clock_set,
.clock_get = sgi_clock_get,
.clock_getres = sgi_clock_getres,
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 8c1e43ab14a9..5166393e19d7 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;
+extern const struct k_clock clock_posix_cpu;
+extern const struct k_clock clock_posix_dynamic;
-void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
+void posix_timers_register_clock(const clockid_t clock_id,
+ const struct k_clock *new_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 5cb5b0008d97..3a5206ee50c1 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -860,6 +860,16 @@ static struct platform_driver alarmtimer_driver = {
}
};
+static 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,
+};
+
/**
* alarmtimer_init - Initialize alarm timer code
*
@@ -871,15 +881,6 @@ 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();
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 31d588d37a17..7e453005e078 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 1370f067fb51..ba79aa955137 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,
@@ -1425,21 +1425,22 @@ struct k_clock clock_posix_cpu = {
.timer_get = posix_cpu_timer_get,
};
+static const 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,
+};
+
+static const struct k_clock thread = {
+ .clock_getres = thread_cpu_clock_getres,
+ .clock_get = thread_cpu_clock_get,
+ .timer_create = thread_cpu_timer_create,
+};
+
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);
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 4d7b2ce09c27..5e01120897fe 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -125,7 +125,7 @@ static DEFINE_SPINLOCK(hash_lock);
* which we beg off on and pass to do_sys_settimeofday().
*/
-static struct k_clock posix_clocks[MAX_CLOCKS];
+static const struct k_clock *posix_clocks[MAX_CLOCKS];
/*
* These ones are defined below.
@@ -280,66 +280,73 @@ 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,
+};
+
/*
* 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);
@@ -522,7 +529,7 @@ static struct pid *good_sigevent(sigevent_t * event)
}
void posix_timers_register_clock(const clockid_t clock_id,
- struct k_clock *new_clock)
+ const struct k_clock *new_clock)
{
if ((unsigned) clock_id >= MAX_CLOCKS) {
printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
@@ -541,7 +548,7 @@ void posix_timers_register_clock(const clockid_t clock_id,
return;
}
- posix_clocks[clock_id] = *new_clock;
+ posix_clocks[clock_id] = new_clock;
}
EXPORT_SYMBOL_GPL(posix_timers_register_clock);
@@ -581,15 +588,16 @@ 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 >= MAX_CLOCKS || !posix_clocks[id] ||
+ !posix_clocks[id]->clock_getres)
return NULL;
- return &posix_clocks[id];
+ return posix_clocks[id];
}
static int common_timer_create(struct k_itimer *new_timer)
@@ -604,7 +612,7 @@ 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 +789,7 @@ 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 +898,7 @@ 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 +947,7 @@ 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 +1026,7 @@ 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 +1043,7 @@ 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 +1063,7 @@ 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 +1086,7 @@ 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 +1118,7 @@ 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 +1144,7 @@ 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;
--
2.11.0