constify struct k_clock

constify struct k_clock

[Christoph Hellwig]

Hi all,

this series constifies all struct k_clock instances as well as the global
posix_clocks array.  To do so it first removes the SGI mmtimer driver,
which only supports very old IA64 hardware, as that drivers has the only
non core kernel struct k_clock instance.

[PATCH 1/2] remove the SGI SN2 mmtimer driver

[Christoph Hellwig]

This driver supports direct system clock access on the ancient SGI SN2
IA64 systems, and implement the only non-builtin k_clock instance.
Remove it as any remaining IA64 altix user will be running just as old
distros anyway.

Note that this does not affect the never uv_mmtimer driver for x86-based
Altix systems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/char/Kconfig   |   9 -
 drivers/char/Makefile  |   1 -
 drivers/char/mmtimer.c | 858 -------------------------------------------------
 3 files changed, 868 deletions(-)
 delete mode 100644 drivers/char/mmtimer.c

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 31adbebf812e..2af70014ee5a 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -539,15 +539,6 @@ config HANGCHECK_TIMER
 	  out to lunch past a certain margin.  It can reboot the system
 	  or merely print a warning.
 
-config MMTIMER
-	tristate "MMTIMER Memory mapped RTC for SGI Altix"
-	depends on IA64_GENERIC || IA64_SGI_SN2
-	depends on POSIX_TIMERS
-	default y
-	help
-	  The mmtimer device allows direct userspace access to the
-	  Altix system timer.
-
 config UV_MMTIMER
 	tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
 	depends on X86_UV
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 6e6c244a66a0..53e33720818c 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -10,7 +10,6 @@ obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_SNSC)		+= snsc.o snsc_event.o
 obj-$(CONFIG_MSPEC)		+= mspec.o
-obj-$(CONFIG_MMTIMER)		+= mmtimer.o
 obj-$(CONFIG_UV_MMTIMER)	+= uv_mmtimer.o
 obj-$(CONFIG_IBM_BSR)		+= bsr.o
 obj-$(CONFIG_SGI_MBCS)		+= mbcs.o
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
deleted file mode 100644
index 0e7fcb04f01e..000000000000
--- a/drivers/char/mmtimer.c
+++ /dev/null
@@ -1,858 +0,0 @@
-/*
- * Timer device implementation for SGI SN platforms.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (c) 2001-2006 Silicon Graphics, Inc.  All rights reserved.
- *
- * This driver exports an API that should be supportable by any HPET or IA-PC
- * multimedia timer.  The code below is currently specific to the SGI Altix
- * SHub RTC, however.
- *
- * 11/01/01 - jbarnes - initial revision
- * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion
- * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE
- * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt
- *		support via the posix timer interface
- */
-
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/ioctl.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/errno.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/mmtimer.h>
-#include <linux/miscdevice.h>
-#include <linux/posix-timers.h>
-#include <linux/interrupt.h>
-#include <linux/time.h>
-#include <linux/math64.h>
-#include <linux/mutex.h>
-#include <linux/slab.h>
-
-#include <linux/uaccess.h>
-#include <asm/sn/addrs.h>
-#include <asm/sn/intr.h>
-#include <asm/sn/shub_mmr.h>
-#include <asm/sn/nodepda.h>
-#include <asm/sn/shubio.h>
-
-MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
-MODULE_DESCRIPTION("SGI Altix RTC Timer");
-MODULE_LICENSE("GPL");
-
-/* name of the device, usually in /dev */
-#define MMTIMER_NAME "mmtimer"
-#define MMTIMER_DESC "SGI Altix RTC Timer"
-#define MMTIMER_VERSION "2.1"
-
-#define RTC_BITS 55 /* 55 bits for this implementation */
-
-static struct k_clock sgi_clock;
-
-extern unsigned long sn_rtc_cycles_per_second;
-
-#define RTC_COUNTER_ADDR        ((long *)LOCAL_MMR_ADDR(SH_RTC))
-
-#define rtc_time()              (*RTC_COUNTER_ADDR)
-
-static DEFINE_MUTEX(mmtimer_mutex);
-static long mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg);
-static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
-
-/*
- * Period in femtoseconds (10^-15 s)
- */
-static unsigned long mmtimer_femtoperiod = 0;
-
-static const struct file_operations mmtimer_fops = {
-	.owner = THIS_MODULE,
-	.mmap =	mmtimer_mmap,
-	.unlocked_ioctl = mmtimer_ioctl,
-	.llseek = noop_llseek,
-};
-
-/*
- * We only have comparison registers RTC1-4 currently available per
- * node.  RTC0 is used by SAL.
- */
-/* Check for an RTC interrupt pending */
-static int mmtimer_int_pending(int comparator)
-{
-	if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) &
-			SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator)
-		return 1;
-	else
-		return 0;
-}
-
-/* Clear the RTC interrupt pending bit */
-static void mmtimer_clr_int_pending(int comparator)
-{
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS),
-		SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator);
-}
-
-/* Setup timer on comparator RTC1 */
-static void mmtimer_setup_int_0(int cpu, u64 expires)
-{
-	u64 val;
-
-	/* Disable interrupt */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L);
-
-	/* Clear pending bit */
-	mmtimer_clr_int_pending(0);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC1_INT_CONFIG_PID_SHFT);
-
-	/* Set configuration */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val);
-
-	/* Enable RTC interrupts */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires);
-
-
-}
-
-/* Setup timer on comparator RTC2 */
-static void mmtimer_setup_int_1(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L);
-
-	mmtimer_clr_int_pending(1);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC2_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires);
-}
-
-/* Setup timer on comparator RTC3 */
-static void mmtimer_setup_int_2(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L);
-
-	mmtimer_clr_int_pending(2);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC3_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires);
-}
-
-/*
- * This function must be called with interrupts disabled and preemption off
- * in order to insure that the setup succeeds in a deterministic time frame.
- * It will check if the interrupt setup succeeded.
- */
-static int mmtimer_setup(int cpu, int comparator, unsigned long expires,
-	u64 *set_completion_time)
-{
-	switch (comparator) {
-	case 0:
-		mmtimer_setup_int_0(cpu, expires);
-		break;
-	case 1:
-		mmtimer_setup_int_1(cpu, expires);
-		break;
-	case 2:
-		mmtimer_setup_int_2(cpu, expires);
-		break;
-	}
-	/* We might've missed our expiration time */
-	*set_completion_time = rtc_time();
-	if (*set_completion_time <= expires)
-		return 1;
-
-	/*
-	 * If an interrupt is already pending then its okay
-	 * if not then we failed
-	 */
-	return mmtimer_int_pending(comparator);
-}
-
-static int mmtimer_disable_int(long nasid, int comparator)
-{
-	switch (comparator) {
-	case 0:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL);
-		break;
-	case 1:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL);
-		break;
-	case 2:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL);
-		break;
-	default:
-		return -EFAULT;
-	}
-	return 0;
-}
-
-#define COMPARATOR	1		/* The comparator to use */
-
-#define TIMER_OFF	0xbadcabLL	/* Timer is not setup */
-#define TIMER_SET	0		/* Comparator is set for this timer */
-
-#define MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT 40
-
-/* There is one of these for each timer */
-struct mmtimer {
-	struct rb_node list;
-	struct k_itimer *timer;
-	int cpu;
-};
-
-struct mmtimer_node {
-	spinlock_t lock ____cacheline_aligned;
-	struct rb_root timer_head;
-	struct rb_node *next;
-	struct tasklet_struct tasklet;
-};
-static struct mmtimer_node *timers;
-
-static unsigned mmtimer_interval_retry_increment =
-	MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT;
-module_param(mmtimer_interval_retry_increment, uint, 0644);
-MODULE_PARM_DESC(mmtimer_interval_retry_increment,
-	"RTC ticks to add to expiration on interval retry (default 40)");
-
-/*
- * Add a new mmtimer struct to the node's mmtimer list.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_add_list(struct mmtimer *n)
-{
-	int nodeid = n->timer->it.mmtimer.node;
-	unsigned long expires = n->timer->it.mmtimer.expires;
-	struct rb_node **link = &timers[nodeid].timer_head.rb_node;
-	struct rb_node *parent = NULL;
-	struct mmtimer *x;
-
-	/*
-	 * Find the right place in the rbtree:
-	 */
-	while (*link) {
-		parent = *link;
-		x = rb_entry(parent, struct mmtimer, list);
-
-		if (expires < x->timer->it.mmtimer.expires)
-			link = &(*link)->rb_left;
-		else
-			link = &(*link)->rb_right;
-	}
-
-	/*
-	 * Insert the timer to the rbtree and check whether it
-	 * replaces the first pending timer
-	 */
-	rb_link_node(&n->list, parent, link);
-	rb_insert_color(&n->list, &timers[nodeid].timer_head);
-
-	if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next,
-			struct mmtimer, list)->timer->it.mmtimer.expires)
-		timers[nodeid].next = &n->list;
-}
-
-/*
- * Set the comparator for the next timer.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_set_next_timer(int nodeid)
-{
-	struct mmtimer_node *n = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	u64 expires, exp, set_completion_time;
-	int i;
-
-restart:
-	if (n->next == NULL)
-		return;
-
-	x = rb_entry(n->next, struct mmtimer, list);
-	t = x->timer;
-	if (!t->it.mmtimer.incr) {
-		/* Not an interval timer */
-		if (!mmtimer_setup(x->cpu, COMPARATOR,
-					t->it.mmtimer.expires,
-					&set_completion_time)) {
-			/* Late setup, fire now */
-			tasklet_schedule(&n->tasklet);
-		}
-		return;
-	}
-
-	/* Interval timer */
-	i = 0;
-	expires = exp = t->it.mmtimer.expires;
-	while (!mmtimer_setup(x->cpu, COMPARATOR, expires,
-				&set_completion_time)) {
-		int to;
-
-		i++;
-		expires = set_completion_time +
-				mmtimer_interval_retry_increment + (1 << i);
-		/* Calculate overruns as we go. */
-		to = ((u64)(expires - exp) / t->it.mmtimer.incr);
-		if (to) {
-			t->it_overrun += to;
-			t->it.mmtimer.expires += t->it.mmtimer.incr * to;
-			exp = t->it.mmtimer.expires;
-		}
-		if (i > 20) {
-			printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
-			t->it.mmtimer.clock = TIMER_OFF;
-			n->next = rb_next(&x->list);
-			rb_erase(&x->list, &n->timer_head);
-			kfree(x);
-			goto restart;
-		}
-	}
-}
-
-/**
- * mmtimer_ioctl - ioctl interface for /dev/mmtimer
- * @file: file structure for the device
- * @cmd: command to execute
- * @arg: optional argument to command
- *
- * Executes the command specified by @cmd.  Returns 0 for success, < 0 for
- * failure.
- *
- * Valid commands:
- *
- * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
- * of the page where the registers are mapped) for the counter in question.
- *
- * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
- * seconds
- *
- * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
- * specified by @arg
- *
- * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
- *
- * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace
- *
- * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
- * in the address specified by @arg.
- */
-static long mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg)
-{
-	int ret = 0;
-
-	mutex_lock(&mmtimer_mutex);
-
-	switch (cmd) {
-	case MMTIMER_GETOFFSET:	/* offset of the counter */
-		/*
-		 * SN RTC registers are on their own 64k page
-		 */
-		if(PAGE_SIZE <= (1 << 16))
-			ret = (((long)RTC_COUNTER_ADDR) & (PAGE_SIZE-1)) / 8;
-		else
-			ret = -ENOSYS;
-		break;
-
-	case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
-		if(copy_to_user((unsigned long __user *)arg,
-				&mmtimer_femtoperiod, sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-
-	case MMTIMER_GETFREQ: /* frequency in Hz */
-		if(copy_to_user((unsigned long __user *)arg,
-				&sn_rtc_cycles_per_second,
-				sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-
-	case MMTIMER_GETBITS: /* number of bits in the clock */
-		ret = RTC_BITS;
-		break;
-
-	case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */
-		ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0;
-		break;
-
-	case MMTIMER_GETCOUNTER:
-		if(copy_to_user((unsigned long __user *)arg,
-				RTC_COUNTER_ADDR, sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-	default:
-		ret = -ENOTTY;
-		break;
-	}
-	mutex_unlock(&mmtimer_mutex);
-	return ret;
-}
-
-/**
- * mmtimer_mmap - maps the clock's registers into userspace
- * @file: file structure for the device
- * @vma: VMA to map the registers into
- *
- * Calls remap_pfn_range() to map the clock's registers into
- * the calling process' address space.
- */
-static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	unsigned long mmtimer_addr;
-
-	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
-		return -EINVAL;
-
-	if (vma->vm_flags & VM_WRITE)
-		return -EPERM;
-
-	if (PAGE_SIZE > (1 << 16))
-		return -ENOSYS;
-
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
-	mmtimer_addr = __pa(RTC_COUNTER_ADDR);
-	mmtimer_addr &= ~(PAGE_SIZE - 1);
-	mmtimer_addr &= 0xfffffffffffffffUL;
-
-	if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT,
-					PAGE_SIZE, vma->vm_page_prot)) {
-		printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n");
-		return -EAGAIN;
-	}
-
-	return 0;
-}
-
-static struct miscdevice mmtimer_miscdev = {
-	.minor = SGI_MMTIMER,
-	.name = MMTIMER_NAME,
-	.fops = &mmtimer_fops
-};
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-/*
- * Posix Timer Interface
- */
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-static int sgi_clock_get(clockid_t clockid, struct timespec64 *tp)
-{
-	u64 nsec;
-
-	nsec = rtc_time() * sgi_clock_period
-			+ sgi_clock_offset.tv_nsec;
-	*tp = ns_to_timespec64(nsec);
-	tp->tv_sec += sgi_clock_offset.tv_sec;
-	return 0;
-};
-
-static int sgi_clock_set(const clockid_t clockid, const struct timespec64 *tp)
-{
-
-	u64 nsec;
-	u32 rem;
-
-	nsec = rtc_time() * sgi_clock_period;
-
-	sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
-
-	if (rem <= tp->tv_nsec)
-		sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
-	else {
-		sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem;
-		sgi_clock_offset.tv_sec--;
-	}
-	return 0;
-}
-
-/**
- * mmtimer_interrupt - timer interrupt handler
- * @irq: irq received
- * @dev_id: device the irq came from
- *
- * Called when one of the comarators matches the counter, This
- * routine will send signals to processes that have requested
- * them.
- *
- * This interrupt is run in an interrupt context
- * by the SHUB. It is therefore safe to locally access SHub
- * registers.
- */
-static irqreturn_t
-mmtimer_interrupt(int irq, void *dev_id)
-{
-	unsigned long expires = 0;
-	int result = IRQ_NONE;
-	unsigned indx = cpu_to_node(smp_processor_id());
-	struct mmtimer *base;
-
-	spin_lock(&timers[indx].lock);
-	base = rb_entry(timers[indx].next, struct mmtimer, list);
-	if (base == NULL) {
-		spin_unlock(&timers[indx].lock);
-		return result;
-	}
-
-	if (base->cpu == smp_processor_id()) {
-		if (base->timer)
-			expires = base->timer->it.mmtimer.expires;
-		/* expires test won't work with shared irqs */
-		if ((mmtimer_int_pending(COMPARATOR) > 0) ||
-			(expires && (expires <= rtc_time()))) {
-			mmtimer_clr_int_pending(COMPARATOR);
-			tasklet_schedule(&timers[indx].tasklet);
-			result = IRQ_HANDLED;
-		}
-	}
-	spin_unlock(&timers[indx].lock);
-	return result;
-}
-
-static void mmtimer_tasklet(unsigned long data)
-{
-	int nodeid = data;
-	struct mmtimer_node *mn = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	unsigned long flags;
-
-	/* Send signal and deal with periodic signals */
-	spin_lock_irqsave(&mn->lock, flags);
-	if (!mn->next)
-		goto out;
-
-	x = rb_entry(mn->next, struct mmtimer, list);
-	t = x->timer;
-
-	if (t->it.mmtimer.clock == TIMER_OFF)
-		goto out;
-
-	t->it_overrun = 0;
-
-	mn->next = rb_next(&x->list);
-	rb_erase(&x->list, &mn->timer_head);
-
-	if (posix_timer_event(t, 0) != 0)
-		t->it_overrun++;
-
-	if(t->it.mmtimer.incr) {
-		t->it.mmtimer.expires += t->it.mmtimer.incr;
-		mmtimer_add_list(x);
-	} else {
-		/* Ensure we don't false trigger in mmtimer_interrupt */
-		t->it.mmtimer.clock = TIMER_OFF;
-		t->it.mmtimer.expires = 0;
-		kfree(x);
-	}
-	/* Set comparator for next timer, if there is one */
-	mmtimer_set_next_timer(nodeid);
-
-	t->it_overrun_last = t->it_overrun;
-out:
-	spin_unlock_irqrestore(&mn->lock, flags);
-}
-
-static int sgi_timer_create(struct k_itimer *timer)
-{
-	/* Insure that a newly created timer is off */
-	timer->it.mmtimer.clock = TIMER_OFF;
-	return 0;
-}
-
-/* This does not really delete a timer. It just insures
- * that the timer is not active
- *
- * Assumption: it_lock is already held with irq's disabled
- */
-static int sgi_timer_del(struct k_itimer *timr)
-{
-	cnodeid_t nodeid = timr->it.mmtimer.node;
-	unsigned long irqflags;
-
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-	if (timr->it.mmtimer.clock != TIMER_OFF) {
-		unsigned long expires = timr->it.mmtimer.expires;
-		struct rb_node *n = timers[nodeid].timer_head.rb_node;
-		struct mmtimer *uninitialized_var(t);
-		int r = 0;
-
-		timr->it.mmtimer.clock = TIMER_OFF;
-		timr->it.mmtimer.expires = 0;
-
-		while (n) {
-			t = rb_entry(n, struct mmtimer, list);
-			if (t->timer == timr)
-				break;
-
-			if (expires < t->timer->it.mmtimer.expires)
-				n = n->rb_left;
-			else
-				n = n->rb_right;
-		}
-
-		if (!n) {
-			spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-			return 0;
-		}
-
-		if (timers[nodeid].next == n) {
-			timers[nodeid].next = rb_next(n);
-			r = 1;
-		}
-
-		rb_erase(n, &timers[nodeid].timer_head);
-		kfree(t);
-
-		if (r) {
-			mmtimer_disable_int(cnodeid_to_nasid(nodeid),
-				COMPARATOR);
-			mmtimer_set_next_timer(nodeid);
-		}
-	}
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-	return 0;
-}
-
-/* Assumption: it_lock is already held with irq's disabled */
-static void sgi_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
-{
-
-	if (timr->it.mmtimer.clock == TIMER_OFF) {
-		cur_setting->it_interval.tv_nsec = 0;
-		cur_setting->it_interval.tv_sec = 0;
-		cur_setting->it_value.tv_nsec = 0;
-		cur_setting->it_value.tv_sec =0;
-		return;
-	}
-
-	cur_setting->it_interval = ns_to_timespec64(timr->it.mmtimer.incr * sgi_clock_period);
-	cur_setting->it_value = ns_to_timespec64((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
-}
-
-
-static int sgi_timer_set(struct k_itimer *timr, int flags,
-	struct itimerspec64 *new_setting,
-	struct itimerspec64 *old_setting)
-{
-	unsigned long when, period, irqflags;
-	int err = 0;
-	cnodeid_t nodeid;
-	struct mmtimer *base;
-	struct rb_node *n;
-
-	if (old_setting)
-		sgi_timer_get(timr, old_setting);
-
-	sgi_timer_del(timr);
-	when = timespec64_to_ns(&new_setting->it_value);
-	period = timespec64_to_ns(&new_setting->it_interval);
-
-	if (when == 0)
-		/* Clear timer */
-		return 0;
-
-	base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL);
-	if (base == NULL)
-		return -ENOMEM;
-
-	if (flags & TIMER_ABSTIME) {
-		struct timespec64 n;
-		unsigned long now;
-
-		getnstimeofday64(&n);
-		now = timespec64_to_ns(&n);
-		if (when > now)
-			when -= now;
-		else
-			/* Fire the timer immediately */
-			when = 0;
-	}
-
-	/*
-	 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
-	 * to getnstimeofday() in order to be as faithful as possible to the time
-	 * specified.
-	 */
-	when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time();
-	period = (period + sgi_clock_period - 1)  / sgi_clock_period;
-
-	/*
-	 * We are allocating a local SHub comparator. If we would be moved to another
-	 * cpu then another SHub may be local to us. Prohibit that by switching off
-	 * preemption.
-	 */
-	preempt_disable();
-
-	nodeid =  cpu_to_node(smp_processor_id());
-
-	/* Lock the node timer structure */
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-
-	base->timer = timr;
-	base->cpu = smp_processor_id();
-
-	timr->it.mmtimer.clock = TIMER_SET;
-	timr->it.mmtimer.node = nodeid;
-	timr->it.mmtimer.incr = period;
-	timr->it.mmtimer.expires = when;
-
-	n = timers[nodeid].next;
-
-	/* Add the new struct mmtimer to node's timer list */
-	mmtimer_add_list(base);
-
-	if (timers[nodeid].next == n) {
-		/* No need to reprogram comparator for now */
-		spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-		preempt_enable();
-		return err;
-	}
-
-	/* We need to reprogram the comparator */
-	if (n)
-		mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR);
-
-	mmtimer_set_next_timer(nodeid);
-
-	/* Unlock the node timer structure */
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-
-	preempt_enable();
-
-	return err;
-}
-
-static int sgi_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
-{
-	tp->tv_sec = 0;
-	tp->tv_nsec = sgi_clock_period;
-	return 0;
-}
-
-static struct k_clock sgi_clock = {
-	.clock_set	= sgi_clock_set,
-	.clock_get	= sgi_clock_get,
-	.clock_getres	= sgi_clock_getres,
-	.timer_create	= sgi_timer_create,
-	.timer_set	= sgi_timer_set,
-	.timer_del	= sgi_timer_del,
-	.timer_get	= sgi_timer_get
-};
-
-/**
- * mmtimer_init - device initialization routine
- *
- * Does initial setup for the mmtimer device.
- */
-static int __init mmtimer_init(void)
-{
-	cnodeid_t node, maxn = -1;
-
-	if (!ia64_platform_is("sn2"))
-		return 0;
-
-	/*
-	 * Sanity check the cycles/sec variable
-	 */
-	if (sn_rtc_cycles_per_second < 100000) {
-		printk(KERN_ERR "%s: unable to determine clock frequency\n",
-		       MMTIMER_NAME);
-		goto out1;
-	}
-
-	mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
-			       2) / sn_rtc_cycles_per_second;
-
-	if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
-		printk(KERN_WARNING "%s: unable to allocate interrupt.",
-			MMTIMER_NAME);
-		goto out1;
-	}
-
-	if (misc_register(&mmtimer_miscdev)) {
-		printk(KERN_ERR "%s: failed to register device\n",
-		       MMTIMER_NAME);
-		goto out2;
-	}
-
-	/* Get max numbered node, calculate slots needed */
-	for_each_online_node(node) {
-		maxn = node;
-	}
-	maxn++;
-
-	/* Allocate list of node ptrs to mmtimer_t's */
-	timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
-	if (!timers) {
-		printk(KERN_ERR "%s: failed to allocate memory for device\n",
-				MMTIMER_NAME);
-		goto out3;
-	}
-
-	/* Initialize struct mmtimer's for each online node */
-	for_each_online_node(node) {
-		spin_lock_init(&timers[node].lock);
-		tasklet_init(&timers[node].tasklet, mmtimer_tasklet,
-			(unsigned long) node);
-	}
-
-	sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
-	posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
-
-	printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
-	       sn_rtc_cycles_per_second/(unsigned long)1E6);
-
-	return 0;
-
-out3:
-	misc_deregister(&mmtimer_miscdev);
-out2:
-	free_irq(SGI_MMTIMER_VECTOR, NULL);
-out1:
-	return -1;
-}
-
-module_init(mmtimer_init);
-- 
2.11.0

[tip:timers/core] mmtimer: Remove the SGI SN2 mmtimer driver

[tip-bot for Christoph Hellwig]

Commit-ID:  07903ada96139ced48f2f893fe57a26a8fbc6043
Gitweb:     http://git.kernel.org/tip/07903ada96139ced48f2f893fe57a26a8fbc6043
Author:     Christoph Hellwig <hch@lst.de>
AuthorDate: Fri, 26 May 2017 12:03:10 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 26 May 2017 12:52:19 +0200

mmtimer: Remove the SGI SN2 mmtimer driver

This driver supports direct system clock access on the ancient SGI SN2
IA64 systems, and implement the only non-builtin k_clock instance.
Remove it as any remaining IA64 altix user will be running just as old
distros anyway.

Dimitri Sivanich stated: "Since this is SN2 specific, this can be removed."

Note that this does not affect the never uv_mmtimer driver for x86-based
Altix systems.

[ tglx: Added comment to CLOCK_SGI_CYCLE ]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-2-hch@lst.de

---
 drivers/char/Kconfig      |   9 -
 drivers/char/Makefile     |   1 -
 drivers/char/mmtimer.c    | 858 ----------------------------------------------
 include/uapi/linux/time.h |   6 +-
 4 files changed, 5 insertions(+), 869 deletions(-)

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 31adbeb..2af7001 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -539,15 +539,6 @@ config HANGCHECK_TIMER
 	  out to lunch past a certain margin.  It can reboot the system
 	  or merely print a warning.
 
-config MMTIMER
-	tristate "MMTIMER Memory mapped RTC for SGI Altix"
-	depends on IA64_GENERIC || IA64_SGI_SN2
-	depends on POSIX_TIMERS
-	default y
-	help
-	  The mmtimer device allows direct userspace access to the
-	  Altix system timer.
-
 config UV_MMTIMER
 	tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
 	depends on X86_UV
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 6e6c244..53e3372 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -10,7 +10,6 @@ obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_SNSC)		+= snsc.o snsc_event.o
 obj-$(CONFIG_MSPEC)		+= mspec.o
-obj-$(CONFIG_MMTIMER)		+= mmtimer.o
 obj-$(CONFIG_UV_MMTIMER)	+= uv_mmtimer.o
 obj-$(CONFIG_IBM_BSR)		+= bsr.o
 obj-$(CONFIG_SGI_MBCS)		+= mbcs.o
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
deleted file mode 100644
index 0e7fcb0..0000000
--- a/drivers/char/mmtimer.c
+++ /dev/null
@@ -1,858 +0,0 @@
-/*
- * Timer device implementation for SGI SN platforms.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (c) 2001-2006 Silicon Graphics, Inc.  All rights reserved.
- *
- * This driver exports an API that should be supportable by any HPET or IA-PC
- * multimedia timer.  The code below is currently specific to the SGI Altix
- * SHub RTC, however.
- *
- * 11/01/01 - jbarnes - initial revision
- * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion
- * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE
- * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt
- *		support via the posix timer interface
- */
-
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/ioctl.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/errno.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/mmtimer.h>
-#include <linux/miscdevice.h>
-#include <linux/posix-timers.h>
-#include <linux/interrupt.h>
-#include <linux/time.h>
-#include <linux/math64.h>
-#include <linux/mutex.h>
-#include <linux/slab.h>
-
-#include <linux/uaccess.h>
-#include <asm/sn/addrs.h>
-#include <asm/sn/intr.h>
-#include <asm/sn/shub_mmr.h>
-#include <asm/sn/nodepda.h>
-#include <asm/sn/shubio.h>
-
-MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
-MODULE_DESCRIPTION("SGI Altix RTC Timer");
-MODULE_LICENSE("GPL");
-
-/* name of the device, usually in /dev */
-#define MMTIMER_NAME "mmtimer"
-#define MMTIMER_DESC "SGI Altix RTC Timer"
-#define MMTIMER_VERSION "2.1"
-
-#define RTC_BITS 55 /* 55 bits for this implementation */
-
-static struct k_clock sgi_clock;
-
-extern unsigned long sn_rtc_cycles_per_second;
-
-#define RTC_COUNTER_ADDR        ((long *)LOCAL_MMR_ADDR(SH_RTC))
-
-#define rtc_time()              (*RTC_COUNTER_ADDR)
-
-static DEFINE_MUTEX(mmtimer_mutex);
-static long mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg);
-static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
-
-/*
- * Period in femtoseconds (10^-15 s)
- */
-static unsigned long mmtimer_femtoperiod = 0;
-
-static const struct file_operations mmtimer_fops = {
-	.owner = THIS_MODULE,
-	.mmap =	mmtimer_mmap,
-	.unlocked_ioctl = mmtimer_ioctl,
-	.llseek = noop_llseek,
-};
-
-/*
- * We only have comparison registers RTC1-4 currently available per
- * node.  RTC0 is used by SAL.
- */
-/* Check for an RTC interrupt pending */
-static int mmtimer_int_pending(int comparator)
-{
-	if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) &
-			SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator)
-		return 1;
-	else
-		return 0;
-}
-
-/* Clear the RTC interrupt pending bit */
-static void mmtimer_clr_int_pending(int comparator)
-{
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS),
-		SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator);
-}
-
-/* Setup timer on comparator RTC1 */
-static void mmtimer_setup_int_0(int cpu, u64 expires)
-{
-	u64 val;
-
-	/* Disable interrupt */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L);
-
-	/* Clear pending bit */
-	mmtimer_clr_int_pending(0);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC1_INT_CONFIG_PID_SHFT);
-
-	/* Set configuration */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val);
-
-	/* Enable RTC interrupts */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires);
-
-
-}
-
-/* Setup timer on comparator RTC2 */
-static void mmtimer_setup_int_1(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L);
-
-	mmtimer_clr_int_pending(1);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC2_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires);
-}
-
-/* Setup timer on comparator RTC3 */
-static void mmtimer_setup_int_2(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L);
-
-	mmtimer_clr_int_pending(2);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC3_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires);
-}
-
-/*
- * This function must be called with interrupts disabled and preemption off
- * in order to insure that the setup succeeds in a deterministic time frame.
- * It will check if the interrupt setup succeeded.
- */
-static int mmtimer_setup(int cpu, int comparator, unsigned long expires,
-	u64 *set_completion_time)
-{
-	switch (comparator) {
-	case 0:
-		mmtimer_setup_int_0(cpu, expires);
-		break;
-	case 1:
-		mmtimer_setup_int_1(cpu, expires);
-		break;
-	case 2:
-		mmtimer_setup_int_2(cpu, expires);
-		break;
-	}
-	/* We might've missed our expiration time */
-	*set_completion_time = rtc_time();
-	if (*set_completion_time <= expires)
-		return 1;
-
-	/*
-	 * If an interrupt is already pending then its okay
-	 * if not then we failed
-	 */
-	return mmtimer_int_pending(comparator);
-}
-
-static int mmtimer_disable_int(long nasid, int comparator)
-{
-	switch (comparator) {
-	case 0:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL);
-		break;
-	case 1:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL);
-		break;
-	case 2:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL);
-		break;
-	default:
-		return -EFAULT;
-	}
-	return 0;
-}
-
-#define COMPARATOR	1		/* The comparator to use */
-
-#define TIMER_OFF	0xbadcabLL	/* Timer is not setup */
-#define TIMER_SET	0		/* Comparator is set for this timer */
-
-#define MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT 40
-
-/* There is one of these for each timer */
-struct mmtimer {
-	struct rb_node list;
-	struct k_itimer *timer;
-	int cpu;
-};
-
-struct mmtimer_node {
-	spinlock_t lock ____cacheline_aligned;
-	struct rb_root timer_head;
-	struct rb_node *next;
-	struct tasklet_struct tasklet;
-};
-static struct mmtimer_node *timers;
-
-static unsigned mmtimer_interval_retry_increment =
-	MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT;
-module_param(mmtimer_interval_retry_increment, uint, 0644);
-MODULE_PARM_DESC(mmtimer_interval_retry_increment,
-	"RTC ticks to add to expiration on interval retry (default 40)");
-
-/*
- * Add a new mmtimer struct to the node's mmtimer list.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_add_list(struct mmtimer *n)
-{
-	int nodeid = n->timer->it.mmtimer.node;
-	unsigned long expires = n->timer->it.mmtimer.expires;
-	struct rb_node **link = &timers[nodeid].timer_head.rb_node;
-	struct rb_node *parent = NULL;
-	struct mmtimer *x;
-
-	/*
-	 * Find the right place in the rbtree:
-	 */
-	while (*link) {
-		parent = *link;
-		x = rb_entry(parent, struct mmtimer, list);
-
-		if (expires < x->timer->it.mmtimer.expires)
-			link = &(*link)->rb_left;
-		else
-			link = &(*link)->rb_right;
-	}
-
-	/*
-	 * Insert the timer to the rbtree and check whether it
-	 * replaces the first pending timer
-	 */
-	rb_link_node(&n->list, parent, link);
-	rb_insert_color(&n->list, &timers[nodeid].timer_head);
-
-	if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next,
-			struct mmtimer, list)->timer->it.mmtimer.expires)
-		timers[nodeid].next = &n->list;
-}
-
-/*
- * Set the comparator for the next timer.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_set_next_timer(int nodeid)
-{
-	struct mmtimer_node *n = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	u64 expires, exp, set_completion_time;
-	int i;
-
-restart:
-	if (n->next == NULL)
-		return;
-
-	x = rb_entry(n->next, struct mmtimer, list);
-	t = x->timer;
-	if (!t->it.mmtimer.incr) {
-		/* Not an interval timer */
-		if (!mmtimer_setup(x->cpu, COMPARATOR,
-					t->it.mmtimer.expires,
-					&set_completion_time)) {
-			/* Late setup, fire now */
-			tasklet_schedule(&n->tasklet);
-		}
-		return;
-	}
-
-	/* Interval timer */
-	i = 0;
-	expires = exp = t->it.mmtimer.expires;
-	while (!mmtimer_setup(x->cpu, COMPARATOR, expires,
-				&set_completion_time)) {
-		int to;
-
-		i++;
-		expires = set_completion_time +
-				mmtimer_interval_retry_increment + (1 << i);
-		/* Calculate overruns as we go. */
-		to = ((u64)(expires - exp) / t->it.mmtimer.incr);
-		if (to) {
-			t->it_overrun += to;
-			t->it.mmtimer.expires += t->it.mmtimer.incr * to;
-			exp = t->it.mmtimer.expires;
-		}
-		if (i > 20) {
-			printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
-			t->it.mmtimer.clock = TIMER_OFF;
-			n->next = rb_next(&x->list);
-			rb_erase(&x->list, &n->timer_head);
-			kfree(x);
-			goto restart;
-		}
-	}
-}
-
-/**
- * mmtimer_ioctl - ioctl interface for /dev/mmtimer
- * @file: file structure for the device
- * @cmd: command to execute
- * @arg: optional argument to command
- *
- * Executes the command specified by @cmd.  Returns 0 for success, < 0 for
- * failure.
- *
- * Valid commands:
- *
- * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
- * of the page where the registers are mapped) for the counter in question.
- *
- * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
- * seconds
- *
- * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
- * specified by @arg
- *
- * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
- *
- * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace
- *
- * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
- * in the address specified by @arg.
- */
-static long mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg)
-{
-	int ret = 0;
-
-	mutex_lock(&mmtimer_mutex);
-
-	switch (cmd) {
-	case MMTIMER_GETOFFSET:	/* offset of the counter */
-		/*
-		 * SN RTC registers are on their own 64k page
-		 */
-		if(PAGE_SIZE <= (1 << 16))
-			ret = (((long)RTC_COUNTER_ADDR) & (PAGE_SIZE-1)) / 8;
-		else
-			ret = -ENOSYS;
-		break;
-
-	case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
-		if(copy_to_user((unsigned long __user *)arg,
-				&mmtimer_femtoperiod, sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-
-	case MMTIMER_GETFREQ: /* frequency in Hz */
-		if(copy_to_user((unsigned long __user *)arg,
-				&sn_rtc_cycles_per_second,
-				sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-
-	case MMTIMER_GETBITS: /* number of bits in the clock */
-		ret = RTC_BITS;
-		break;
-
-	case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */
-		ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0;
-		break;
-
-	case MMTIMER_GETCOUNTER:
-		if(copy_to_user((unsigned long __user *)arg,
-				RTC_COUNTER_ADDR, sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-	default:
-		ret = -ENOTTY;
-		break;
-	}
-	mutex_unlock(&mmtimer_mutex);
-	return ret;
-}
-
-/**
- * mmtimer_mmap - maps the clock's registers into userspace
- * @file: file structure for the device
- * @vma: VMA to map the registers into
- *
- * Calls remap_pfn_range() to map the clock's registers into
- * the calling process' address space.
- */
-static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	unsigned long mmtimer_addr;
-
-	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
-		return -EINVAL;
-
-	if (vma->vm_flags & VM_WRITE)
-		return -EPERM;
-
-	if (PAGE_SIZE > (1 << 16))
-		return -ENOSYS;
-
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
-	mmtimer_addr = __pa(RTC_COUNTER_ADDR);
-	mmtimer_addr &= ~(PAGE_SIZE - 1);
-	mmtimer_addr &= 0xfffffffffffffffUL;
-
-	if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT,
-					PAGE_SIZE, vma->vm_page_prot)) {
-		printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n");
-		return -EAGAIN;
-	}
-
-	return 0;
-}
-
-static struct miscdevice mmtimer_miscdev = {
-	.minor = SGI_MMTIMER,
-	.name = MMTIMER_NAME,
-	.fops = &mmtimer_fops
-};
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-/*
- * Posix Timer Interface
- */
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-static int sgi_clock_get(clockid_t clockid, struct timespec64 *tp)
-{
-	u64 nsec;
-
-	nsec = rtc_time() * sgi_clock_period
-			+ sgi_clock_offset.tv_nsec;
-	*tp = ns_to_timespec64(nsec);
-	tp->tv_sec += sgi_clock_offset.tv_sec;
-	return 0;
-};
-
-static int sgi_clock_set(const clockid_t clockid, const struct timespec64 *tp)
-{
-
-	u64 nsec;
-	u32 rem;
-
-	nsec = rtc_time() * sgi_clock_period;
-
-	sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
-
-	if (rem <= tp->tv_nsec)
-		sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
-	else {
-		sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem;
-		sgi_clock_offset.tv_sec--;
-	}
-	return 0;
-}
-
-/**
- * mmtimer_interrupt - timer interrupt handler
- * @irq: irq received
- * @dev_id: device the irq came from
- *
- * Called when one of the comarators matches the counter, This
- * routine will send signals to processes that have requested
- * them.
- *
- * This interrupt is run in an interrupt context
- * by the SHUB. It is therefore safe to locally access SHub
- * registers.
- */
-static irqreturn_t
-mmtimer_interrupt(int irq, void *dev_id)
-{
-	unsigned long expires = 0;
-	int result = IRQ_NONE;
-	unsigned indx = cpu_to_node(smp_processor_id());
-	struct mmtimer *base;
-
-	spin_lock(&timers[indx].lock);
-	base = rb_entry(timers[indx].next, struct mmtimer, list);
-	if (base == NULL) {
-		spin_unlock(&timers[indx].lock);
-		return result;
-	}
-
-	if (base->cpu == smp_processor_id()) {
-		if (base->timer)
-			expires = base->timer->it.mmtimer.expires;
-		/* expires test won't work with shared irqs */
-		if ((mmtimer_int_pending(COMPARATOR) > 0) ||
-			(expires && (expires <= rtc_time()))) {
-			mmtimer_clr_int_pending(COMPARATOR);
-			tasklet_schedule(&timers[indx].tasklet);
-			result = IRQ_HANDLED;
-		}
-	}
-	spin_unlock(&timers[indx].lock);
-	return result;
-}
-
-static void mmtimer_tasklet(unsigned long data)
-{
-	int nodeid = data;
-	struct mmtimer_node *mn = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	unsigned long flags;
-
-	/* Send signal and deal with periodic signals */
-	spin_lock_irqsave(&mn->lock, flags);
-	if (!mn->next)
-		goto out;
-
-	x = rb_entry(mn->next, struct mmtimer, list);
-	t = x->timer;
-
-	if (t->it.mmtimer.clock == TIMER_OFF)
-		goto out;
-
-	t->it_overrun = 0;
-
-	mn->next = rb_next(&x->list);
-	rb_erase(&x->list, &mn->timer_head);
-
-	if (posix_timer_event(t, 0) != 0)
-		t->it_overrun++;
-
-	if(t->it.mmtimer.incr) {
-		t->it.mmtimer.expires += t->it.mmtimer.incr;
-		mmtimer_add_list(x);
-	} else {
-		/* Ensure we don't false trigger in mmtimer_interrupt */
-		t->it.mmtimer.clock = TIMER_OFF;
-		t->it.mmtimer.expires = 0;
-		kfree(x);
-	}
-	/* Set comparator for next timer, if there is one */
-	mmtimer_set_next_timer(nodeid);
-
-	t->it_overrun_last = t->it_overrun;
-out:
-	spin_unlock_irqrestore(&mn->lock, flags);
-}
-
-static int sgi_timer_create(struct k_itimer *timer)
-{
-	/* Insure that a newly created timer is off */
-	timer->it.mmtimer.clock = TIMER_OFF;
-	return 0;
-}
-
-/* This does not really delete a timer. It just insures
- * that the timer is not active
- *
- * Assumption: it_lock is already held with irq's disabled
- */
-static int sgi_timer_del(struct k_itimer *timr)
-{
-	cnodeid_t nodeid = timr->it.mmtimer.node;
-	unsigned long irqflags;
-
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-	if (timr->it.mmtimer.clock != TIMER_OFF) {
-		unsigned long expires = timr->it.mmtimer.expires;
-		struct rb_node *n = timers[nodeid].timer_head.rb_node;
-		struct mmtimer *uninitialized_var(t);
-		int r = 0;
-
-		timr->it.mmtimer.clock = TIMER_OFF;
-		timr->it.mmtimer.expires = 0;
-
-		while (n) {
-			t = rb_entry(n, struct mmtimer, list);
-			if (t->timer == timr)
-				break;
-
-			if (expires < t->timer->it.mmtimer.expires)
-				n = n->rb_left;
-			else
-				n = n->rb_right;
-		}
-
-		if (!n) {
-			spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-			return 0;
-		}
-
-		if (timers[nodeid].next == n) {
-			timers[nodeid].next = rb_next(n);
-			r = 1;
-		}
-
-		rb_erase(n, &timers[nodeid].timer_head);
-		kfree(t);
-
-		if (r) {
-			mmtimer_disable_int(cnodeid_to_nasid(nodeid),
-				COMPARATOR);
-			mmtimer_set_next_timer(nodeid);
-		}
-	}
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-	return 0;
-}
-
-/* Assumption: it_lock is already held with irq's disabled */
-static void sgi_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
-{
-
-	if (timr->it.mmtimer.clock == TIMER_OFF) {
-		cur_setting->it_interval.tv_nsec = 0;
-		cur_setting->it_interval.tv_sec = 0;
-		cur_setting->it_value.tv_nsec = 0;
-		cur_setting->it_value.tv_sec =0;
-		return;
-	}
-
-	cur_setting->it_interval = ns_to_timespec64(timr->it.mmtimer.incr * sgi_clock_period);
-	cur_setting->it_value = ns_to_timespec64((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
-}
-
-
-static int sgi_timer_set(struct k_itimer *timr, int flags,
-	struct itimerspec64 *new_setting,
-	struct itimerspec64 *old_setting)
-{
-	unsigned long when, period, irqflags;
-	int err = 0;
-	cnodeid_t nodeid;
-	struct mmtimer *base;
-	struct rb_node *n;
-
-	if (old_setting)
-		sgi_timer_get(timr, old_setting);
-
-	sgi_timer_del(timr);
-	when = timespec64_to_ns(&new_setting->it_value);
-	period = timespec64_to_ns(&new_setting->it_interval);
-
-	if (when == 0)
-		/* Clear timer */
-		return 0;
-
-	base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL);
-	if (base == NULL)
-		return -ENOMEM;
-
-	if (flags & TIMER_ABSTIME) {
-		struct timespec64 n;
-		unsigned long now;
-
-		getnstimeofday64(&n);
-		now = timespec64_to_ns(&n);
-		if (when > now)
-			when -= now;
-		else
-			/* Fire the timer immediately */
-			when = 0;
-	}
-
-	/*
-	 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
-	 * to getnstimeofday() in order to be as faithful as possible to the time
-	 * specified.
-	 */
-	when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time();
-	period = (period + sgi_clock_period - 1)  / sgi_clock_period;
-
-	/*
-	 * We are allocating a local SHub comparator. If we would be moved to another
-	 * cpu then another SHub may be local to us. Prohibit that by switching off
-	 * preemption.
-	 */
-	preempt_disable();
-
-	nodeid =  cpu_to_node(smp_processor_id());
-
-	/* Lock the node timer structure */
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-
-	base->timer = timr;
-	base->cpu = smp_processor_id();
-
-	timr->it.mmtimer.clock = TIMER_SET;
-	timr->it.mmtimer.node = nodeid;
-	timr->it.mmtimer.incr = period;
-	timr->it.mmtimer.expires = when;
-
-	n = timers[nodeid].next;
-
-	/* Add the new struct mmtimer to node's timer list */
-	mmtimer_add_list(base);
-
-	if (timers[nodeid].next == n) {
-		/* No need to reprogram comparator for now */
-		spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-		preempt_enable();
-		return err;
-	}
-
-	/* We need to reprogram the comparator */
-	if (n)
-		mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR);
-
-	mmtimer_set_next_timer(nodeid);
-
-	/* Unlock the node timer structure */
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-
-	preempt_enable();
-
-	return err;
-}
-
-static int sgi_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
-{
-	tp->tv_sec = 0;
-	tp->tv_nsec = sgi_clock_period;
-	return 0;
-}
-
-static struct k_clock sgi_clock = {
-	.clock_set	= sgi_clock_set,
-	.clock_get	= sgi_clock_get,
-	.clock_getres	= sgi_clock_getres,
-	.timer_create	= sgi_timer_create,
-	.timer_set	= sgi_timer_set,
-	.timer_del	= sgi_timer_del,
-	.timer_get	= sgi_timer_get
-};
-
-/**
- * mmtimer_init - device initialization routine
- *
- * Does initial setup for the mmtimer device.
- */
-static int __init mmtimer_init(void)
-{
-	cnodeid_t node, maxn = -1;
-
-	if (!ia64_platform_is("sn2"))
-		return 0;
-
-	/*
-	 * Sanity check the cycles/sec variable
-	 */
-	if (sn_rtc_cycles_per_second < 100000) {
-		printk(KERN_ERR "%s: unable to determine clock frequency\n",
-		       MMTIMER_NAME);
-		goto out1;
-	}
-
-	mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
-			       2) / sn_rtc_cycles_per_second;
-
-	if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
-		printk(KERN_WARNING "%s: unable to allocate interrupt.",
-			MMTIMER_NAME);
-		goto out1;
-	}
-
-	if (misc_register(&mmtimer_miscdev)) {
-		printk(KERN_ERR "%s: failed to register device\n",
-		       MMTIMER_NAME);
-		goto out2;
-	}
-
-	/* Get max numbered node, calculate slots needed */
-	for_each_online_node(node) {
-		maxn = node;
-	}
-	maxn++;
-
-	/* Allocate list of node ptrs to mmtimer_t's */
-	timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
-	if (!timers) {
-		printk(KERN_ERR "%s: failed to allocate memory for device\n",
-				MMTIMER_NAME);
-		goto out3;
-	}
-
-	/* Initialize struct mmtimer's for each online node */
-	for_each_online_node(node) {
-		spin_lock_init(&timers[node].lock);
-		tasklet_init(&timers[node].tasklet, mmtimer_tasklet,
-			(unsigned long) node);
-	}
-
-	sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
-	posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
-
-	printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
-	       sn_rtc_cycles_per_second/(unsigned long)1E6);
-
-	return 0;
-
-out3:
-	misc_deregister(&mmtimer_miscdev);
-out2:
-	free_irq(SGI_MMTIMER_VECTOR, NULL);
-out1:
-	return -1;
-}
-
-module_init(mmtimer_init);
diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
index e75e1b6..09299fc 100644
--- a/include/uapi/linux/time.h
+++ b/include/uapi/linux/time.h
@@ -54,7 +54,11 @@ struct itimerval {
 #define CLOCK_BOOTTIME			7
 #define CLOCK_REALTIME_ALARM		8
 #define CLOCK_BOOTTIME_ALARM		9
-#define CLOCK_SGI_CYCLE			10	/* Hardware specific */
+/*
+ * The driver implementing this got removed. The clock ID is kept as a
+ * place holder. Do not reuse!
+ */
+#define CLOCK_SGI_CYCLE			10
 #define CLOCK_TAI			11
 
 #define MAX_CLOCKS			16

Re: [tip:timers/core] mmtimer: Remove the SGI SN2 mmtimer driver

[Joe Perches]

On Fri, 2017-05-26 at 03:58 -0700, tip-bot for Christoph Hellwig wrote:
> Commit-ID:  07903ada96139ced48f2f893fe57a26a8fbc6043

Couple trivial comments:

> mmtimer: Remove the SGI SN2 mmtimer driver
[]
>  drivers/char/mmtimer.c    | 858 ----------------------------------------------
>  include/uapi/linux/time.h |   6 +-
[]
> diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
> deleted file mode 100644
> index 0e7fcb0..0000000
> --- a/drivers/char/mmtimer.c
> +++ /dev/null
> @@ -1,858 +0,0 @@
> -/*

[ etc...]

In the future, please use git format-patch -M to avoid
listing the
contents of the file deletion.

> diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
[]
> @@ -54,7 +54,11 @@ struct itimerval {
>  #define CLOCK_BOOTTIME			7
>  #define CLOCK_REALTIME_ALARM		8
>  #define CLOCK_BOOTTIME_ALARM		9
> -#define CLOCK_SGI_CYCLE			10	/* Hardware specific */
> +/*
> + * The driver implementing this got removed. The clock ID is kept as a
> + * place holder. Do not reuse!
> + */
> +#define CLOCK_SGI_CYCLE			10
>  #define CLOCK_TAI			11
>  
>  #define MAX_CLOCKS			16

Here the "this" comment is a bit ambiguous.

It might be better to rename CLOCK_SGI_CYCLE as well.
Maybe something like CLOCK_SGI_CYCLE_DELETED_DRIVER_DONT_REUSE.

[PATCH 2/2] kernel: mark all struct k_clock instances const

[Christoph Hellwig]

And initialize the array statically at compile time.   Originally
based on changes in the Grsecurity patch set, but redone for mainline
to be slightly cleaner, and take the SGI mmtimer removal into account,
which allows for a completely static initialization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 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 8c1e43ab14a9..b313ef2e7385 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 5cb5b0008d97..2914ead22a8d 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.
@@ -860,6 +860,17 @@ static struct platform_driver alarmtimer_driver = {
 	}
 };
 
+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 */
+
 /**
  * alarmtimer_init - Initialize alarm timer code
  *
@@ -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 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..1a522b39f19d 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 4d7b2ce09c27..0c0cccfa3586 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;
-- 
2.11.0

Re: [PATCH 2/2] kernel: mark all struct k_clock instances const

[Joe Perches]

On Fri, 2017-05-26 at 12:03 +0300, Christoph Hellwig wrote:
> And initialize the array statically at compile time.   Originally
> based on changes in the Grsecurity patch set, but redone for mainline
> to be slightly cleaner, and take the SGI mmtimer removal into account,
> which allows for a completely static initialization.

Maybe add k_clock to scripts/const_structs.checkpatch
---
$ git diff --stat -p scripts/const_structs.checkpatch
 scripts/const_structs.checkpatch | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/const_structs.checkpatch b/scripts/const_structs.checkpatch
index ac5f1267151d..b2a2316964a8 100644
--- a/scripts/const_structs.checkpatch
+++ b/scripts/const_structs.checkpatch
@@ -25,6 +25,7 @@ irq_domain_ops
 item_operations
 iwl_cfg
 iwl_ops
+k_clock
 kgdb_arch
 kgdb_io
 kset_uevent_ops

Re: [PATCH 2/2] kernel: mark all struct k_clock instances const

[Thomas Gleixner]

[-- Attachment #1: Type: text/plain, Size: 964 bytes --]

On Fri, 26 May 2017, Joe Perches wrote:

> On Fri, 2017-05-26 at 12:03 +0300, Christoph Hellwig wrote:
> > And initialize the array statically at compile time.   Originally
> > based on changes in the Grsecurity patch set, but redone for mainline
> > to be slightly cleaner, and take the SGI mmtimer removal into account,
> > which allows for a completely static initialization.
> 
> Maybe add k_clock to scripts/const_structs.checkpatch

Care to send a proper patch with changelog?

> ---
> $ git diff --stat -p scripts/const_structs.checkpatch
>  scripts/const_structs.checkpatch | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/scripts/const_structs.checkpatch b/scripts/const_structs.checkpatch
> index ac5f1267151d..b2a2316964a8 100644
> --- a/scripts/const_structs.checkpatch
> +++ b/scripts/const_structs.checkpatch
> @@ -25,6 +25,7 @@ irq_domain_ops
>  item_operations
>  iwl_cfg
>  iwl_ops
> +k_clock
>  kgdb_arch
>  kgdb_io
>  kset_uevent_ops
> 

Re: [PATCH 2/2] kernel: mark all struct k_clock instances const

[Joe Perches]

On Fri, 2017-05-26 at 12:32 +0200, Thomas Gleixner wrote:
> On Fri, 26 May 2017, Joe Perches wrote:
> > On Fri, 2017-05-26 at 12:03 +0300, Christoph Hellwig wrote:
> > > And initialize the array statically at compile time.   Originally
> > > based on changes in the Grsecurity patch set, but redone for mainline
> > > to be slightly cleaner, and take the SGI mmtimer removal into account,
> > > which allows for a completely static initialization.
> > 
> > Maybe add k_clock to scripts/const_structs.checkpatch
> Care to send a proper patch with changelog?

After Christoph's patch is in -next so I can reference
the proper commit SHA1.

[tip:timers/core] posix-timers: Make posix_clocks immutable

[tip-bot for Christoph Hellwig]

Commit-ID:  74377deb3c19639ab5c0a8c2b5301d67c45ba83c
Gitweb:     http://git.kernel.org/tip/74377deb3c19639ab5c0a8c2b5301d67c45ba83c
Author:     Christoph Hellwig <hch@lst.de>
AuthorDate: Fri, 26 May 2017 12:03:11 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 26 May 2017 12:52:20 +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 ]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@lst.de

---
 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..2914ead 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.
@@ -860,6 +860,17 @@ static struct platform_driver alarmtimer_driver = {
 	}
 };
 
+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 */
+
 /**
  * alarmtimer_init - Initialize alarm timer code
  *
@@ -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;

[tip:timers/core] posix-timers: Make posix_clocks immutable

[tip-bot for Christoph Hellwig]

Commit-ID:  82def146e8f511c37d8d8934202491483dd09ca9
Gitweb:     http://git.kernel.org/tip/82def146e8f511c37d8d8934202491483dd09ca9
Author:     Christoph Hellwig <hch@lst.de>
AuthorDate: Fri, 26 May 2017 12:03:11 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
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@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@lst.de
---
 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;

[tip:timers/core] posix-timers: Make posix_clocks immutable

[tip-bot for Christoph Hellwig]

Commit-ID:  d346807445883732d530a62ebadb69af2f017e28
Gitweb:     http://git.kernel.org/tip/d346807445883732d530a62ebadb69af2f017e28
Author:     Christoph Hellwig <hch@lst.de>
AuthorDate: Fri, 26 May 2017 12:03:11 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 26 May 2017 14:35:06 +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@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@lst.de
---
 kernel/time/alarmtimer.c | 64 ++++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 7b5b7bf..4f4cc35 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -307,38 +307,6 @@ static int alarmtimer_resume(struct device *dev)
 }
 #endif
 
-static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
-{
-	struct alarm_base *base;
-	unsigned long flags;
-	ktime_t delta;
-
-	switch(type) {
-	case ALARM_REALTIME:
-		base = &alarm_bases[ALARM_REALTIME];
-		type = ALARM_REALTIME_FREEZER;
-		break;
-	case ALARM_BOOTTIME:
-		base = &alarm_bases[ALARM_BOOTTIME];
-		type = ALARM_BOOTTIME_FREEZER;
-		break;
-	default:
-		WARN_ONCE(1, "Invalid alarm type: %d\n", type);
-		return;
-	}
-
-	delta = ktime_sub(absexp, base->gettime());
-
-	spin_lock_irqsave(&freezer_delta_lock, flags);
-	if (!freezer_delta || (delta < freezer_delta)) {
-		freezer_delta = delta;
-		freezer_expires = absexp;
-		freezer_alarmtype = type;
-	}
-	spin_unlock_irqrestore(&freezer_delta_lock, flags);
-}
-
-
 /**
  * alarm_init - Initialize an alarm structure
  * @alarm: ptr to alarm to be initialized
@@ -489,6 +457,38 @@ u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
 EXPORT_SYMBOL_GPL(alarm_forward_now);
 
 #ifdef CONFIG_POSIX_TIMERS
+
+static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
+{
+	struct alarm_base *base;
+	unsigned long flags;
+	ktime_t delta;
+
+	switch(type) {
+	case ALARM_REALTIME:
+		base = &alarm_bases[ALARM_REALTIME];
+		type = ALARM_REALTIME_FREEZER;
+		break;
+	case ALARM_BOOTTIME:
+		base = &alarm_bases[ALARM_BOOTTIME];
+		type = ALARM_BOOTTIME_FREEZER;
+		break;
+	default:
+		WARN_ONCE(1, "Invalid alarm type: %d\n", type);
+		return;
+	}
+
+	delta = ktime_sub(absexp, base->gettime());
+
+	spin_lock_irqsave(&freezer_delta_lock, flags);
+	if (!freezer_delta || (delta < freezer_delta)) {
+		freezer_delta = delta;
+		freezer_expires = absexp;
+		freezer_alarmtype = type;
+	}
+	spin_unlock_irqrestore(&freezer_delta_lock, flags);
+}
+
 /**
  * clock2alarm - helper that converts from clockid to alarmtypes
  * @clockid: clockid.

[tip:timers/core] posix-timers: Make posix_clocks immutable

[tip-bot for Christoph Hellwig]

Commit-ID:  d3ba5a9a345b1243276f8a982e1bce557c2504fd
Gitweb:     http://git.kernel.org/tip/d3ba5a9a345b1243276f8a982e1bce557c2504fd
Author:     Christoph Hellwig <hch@lst.de>
AuthorDate: Fri, 26 May 2017 12:03:11 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 27 May 2017 09:46:35 +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@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@lst.de
---
 include/linux/posix-timers.h   |   9 +-
 kernel/time/alarmtimer.c       |  89 ++++++++++---------
 kernel/time/posix-clock.c      |   2 +-
 kernel/time/posix-cpu-timers.c |  34 +++-----
 kernel/time/posix-timers.c     | 191 +++++++++++++++++++----------------------
 5 files changed, 151 insertions(+), 174 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..4f4cc35 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -307,38 +307,6 @@ static int alarmtimer_resume(struct device *dev)
 }
 #endif
 
-static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
-{
-	struct alarm_base *base;
-	unsigned long flags;
-	ktime_t delta;
-
-	switch(type) {
-	case ALARM_REALTIME:
-		base = &alarm_bases[ALARM_REALTIME];
-		type = ALARM_REALTIME_FREEZER;
-		break;
-	case ALARM_BOOTTIME:
-		base = &alarm_bases[ALARM_BOOTTIME];
-		type = ALARM_BOOTTIME_FREEZER;
-		break;
-	default:
-		WARN_ONCE(1, "Invalid alarm type: %d\n", type);
-		return;
-	}
-
-	delta = ktime_sub(absexp, base->gettime());
-
-	spin_lock_irqsave(&freezer_delta_lock, flags);
-	if (!freezer_delta || (delta < freezer_delta)) {
-		freezer_delta = delta;
-		freezer_expires = absexp;
-		freezer_alarmtype = type;
-	}
-	spin_unlock_irqrestore(&freezer_delta_lock, flags);
-}
-
-
 /**
  * alarm_init - Initialize an alarm structure
  * @alarm: ptr to alarm to be initialized
@@ -488,6 +456,38 @@ u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
 }
 EXPORT_SYMBOL_GPL(alarm_forward_now);
 
+#ifdef CONFIG_POSIX_TIMERS
+
+static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
+{
+	struct alarm_base *base;
+	unsigned long flags;
+	ktime_t delta;
+
+	switch(type) {
+	case ALARM_REALTIME:
+		base = &alarm_bases[ALARM_REALTIME];
+		type = ALARM_REALTIME_FREEZER;
+		break;
+	case ALARM_BOOTTIME:
+		base = &alarm_bases[ALARM_BOOTTIME];
+		type = ALARM_BOOTTIME_FREEZER;
+		break;
+	default:
+		WARN_ONCE(1, "Invalid alarm type: %d\n", type);
+		return;
+	}
+
+	delta = ktime_sub(absexp, base->gettime());
+
+	spin_lock_irqsave(&freezer_delta_lock, flags);
+	if (!freezer_delta || (delta < freezer_delta)) {
+		freezer_delta = delta;
+		freezer_expires = absexp;
+		freezer_alarmtype = type;
+	}
+	spin_unlock_irqrestore(&freezer_delta_lock, flags);
+}
 
 /**
  * clock2alarm - helper that converts from clockid to alarmtypes
@@ -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;