litmus-rt.git - The LITMUS^RT kernel.

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author	Kyle McMartin <kyle@mcmartin.ca>	2008-07-29 00:11:13 -0400
committer	Kyle McMartin <kyle@hera.kernel.org>	2008-10-10 12:32:30 -0400
commit	089d55289db5d58d938d73b47a415b2b82ee19ac (patch)
tree	4d7cdbc5a7dc8fb7fccf0d579f4296197f05f086 /arch
parent	24b574d052a1996bac42fbd56715ab602092c291 (diff)

parisc: hijack jump to start_kernel

Bang in our own start_parisc call, which initializes the PDC width, and turns on the FPU. Previously, if CONFIG_PRINTK_TIME was on, we'd attempt to use the FPU before we had enabled it, resulting in a difficult to diagnose panic. This patch causes init_per_cpu to redundantly set these for cpu0, but this is harmless.

Diffstat (limited to 'arch')

-rw-r--r--

arch/parisc/kernel/head.S

-rw-r--r--

arch/parisc/kernel/setup.c

2 files changed, 27 insertions, 2 deletions


diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S index a84e31e82876..0e3d9f9b9e33 100644 --- a/arch/parisc/kernel/head.S +++ b/arch/parisc/kernel/head.S
@@ -121,7 +121,7 @@ $pgt_fill_loop:
121	copy %r0,%r2	121	copy %r0,%r2
122		122
123	/* And the RFI Target address too */	123	/* And the RFI Target address too */
124	load32 start_kernel,%r11	124	load32 start_parisc,%r11
125		125
126	/* And the initial task pointer */	126	/* And the initial task pointer */
127	load32 init_thread_union,%r6	127	load32 init_thread_union,%r6


diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c index 39e7c5a5946a..a59b71efdbe5 100644 --- a/arch/parisc/kernel/setup.c +++ b/arch/parisc/kernel/setup.c
@@ -368,6 +368,31 @@ static int __init parisc_init(void)
368		368
369	return 0;	369	return 0;
370	}	370	}
371
372	arch_initcall(parisc_init);	371	arch_initcall(parisc_init);
373		372
		373	void start_parisc(void)
		374	{
		375	extern void start_kernel(void);
		376
		377	int ret, cpunum;
		378	struct pdc_coproc_cfg coproc_cfg;
		379
		380	cpunum = smp_processor_id();
		381
		382	set_firmware_width_unlocked();
		383
		384	ret = pdc_coproc_cfg_unlocked(&coproc_cfg);
		385	if (ret >= 0 && coproc_cfg.ccr_functional) {
		386	mtctl(coproc_cfg.ccr_functional, 10);
		387
		388	cpu_data[cpunum].fp_rev = coproc_cfg.revision;
		389	cpu_data[cpunum].fp_model = coproc_cfg.model;
		390
		391	asm volatile ("fstd %fr0,8(%sp)");
		392	} else {
		393	panic("must have an fpu to boot linux");
		394	}
		395
		396	start_kernel();
		397	// not reached
		398	}

/* * fs/eventpoll.c (Efficient event retrieval implementation) * Copyright (C) 2001,...,2009 Davide Libenzi * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Davide Libenzi <davidel@xmailserver.org> * */ #include <linux/init.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/poll.h> #include <linux/string.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/spinlock.h> #include <linux/syscalls.h> #include <linux/rbtree.h> #include <linux/wait.h> #include <linux/eventpoll.h> #include <linux/mount.h> #include <linux/bitops.h> #include <linux/mutex.h> #include <linux/anon_inodes.h> #include <linux/device.h> #include <linux/freezer.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/mman.h> #include <linux/atomic.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/compat.h> /* * LOCKING: * There are three level of locking required by epoll : * * 1) epmutex (mutex) * 2) ep->mtx (mutex) * 3) ep->lock (spinlock) * * The acquire order is the one listed above, from 1 to 3. * We need a spinlock (ep->lock) because we manipulate objects * from inside the poll callback, that might be triggered from * a wake_up() that in turn might be called from IRQ context. * So we can't sleep inside the poll callback and hence we need * a spinlock. During the event transfer loop (from kernel to * user space) we could end up sleeping due a copy_to_user(), so * we need a lock that will allow us to sleep. This lock is a * mutex (ep->mtx). It is acquired during the event transfer loop, * during epoll_ctl(EPOLL_CTL_DEL) and during eventpoll_release_file(). * Then we also need a global mutex to serialize eventpoll_release_file() * and ep_free(). * This mutex is acquired by ep_free() during the epoll file * cleanup path and it is also acquired by eventpoll_release_file() * if a file has been pushed inside an epoll set and it is then * close()d without a previous call to epoll_ctl(EPOLL_CTL_DEL). * It is also acquired when inserting an epoll fd onto another epoll * fd. We do this so that we walk the epoll tree and ensure that this * insertion does not create a cycle of epoll file descriptors, which * could lead to deadlock. We need a global mutex to prevent two * simultaneous inserts (A into B and B into A) from racing and * constructing a cycle without either insert observing that it is * going to. * It is necessary to acquire multiple "ep->mtx"es at once in the * case when one epoll fd is added to another. In this case, we * always acquire the locks in the order of nesting (i.e. after * epoll_ctl(e1, EPOLL_CTL_ADD, e2), e1->mtx will always be acquired * before e2->mtx). Since we disallow cycles of epoll file * descriptors, this ensures that the mutexes are well-ordered. In * order to communicate this nesting to lockdep, when walking a tree * of epoll file descriptors, we use the current recursion depth as * the lockdep subkey. * It is possible to drop the "ep->mtx" and to use the global * mutex "epmutex" (together with "ep->lock") to have it working, * but having "ep->mtx" will make the interface more scalable. * Events that require holding "epmutex" are very rare, while for * normal operations the epoll private "ep->mtx" will guarantee * a better scalability. */ /* Epoll private bits inside the event mask */ #define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET) /* Maximum number of nesting allowed inside epoll sets */ #define EP_MAX_NESTS 4 #define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) #define EP_UNACTIVE_PTR ((void *) -1L) #define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry)) struct epoll_filefd { struct file *file; int fd; } __packed; /* * Structure used to track possible nested calls, for too deep recursions * and loop cycles. */ struct nested_call_node { struct list_head llink; void *cookie; void *ctx; }; /* * This structure is used as collector for nested calls, to check for * maximum recursion dept and loop cycles. */ struct nested_calls { struct list_head tasks_call_list; spinlock_t lock; }; /* * Each file descriptor added to the eventpoll interface will * have an entry of this type linked to the "rbr" RB tree. * Avoid increasing the size of this struct, there can be many thousands * of these on a server and we do not want this to take another cache line. */ struct epitem { /* RB tree node used to link this structure to the eventpoll RB tree */ struct rb_node rbn; /* List header used to link this structure to the eventpoll ready list */ struct list_head rdllink; /* * Works together "struct eventpoll"->ovflist in keeping the * single linked chain of items. */ struct epitem *next; /* The file descriptor information this item refers to */ struct epoll_filefd ffd; /* Number of active wait queue attached to poll operations */ int nwait; /* List containing poll wait queues */ struct list_head pwqlist; /* The "container" of this item */ struct eventpoll *ep; /* List header used to link this item to the "struct file" items list */ struct list_head fllink; /* wakeup_source used when EPOLLWAKEUP is set */ struct wakeup_source __rcu *ws; /* The structure that describe the interested events and the source fd */ struct epoll_event event; }; /* * This structure is stored inside the "private_data" member of the file * structure and represents the main data structure for the eventpoll * interface. */ struct eventpoll { /* Protect the access to this structure */ spinlock_t lock; /* * This mutex is used to ensure that files are not removed * while epoll is using them. This is held during the event * collection loop, the file cleanup path, the epoll file exit * code and the ctl operations. */ struct mutex mtx; /* Wait queue used by sys_epoll_wait() */ wait_queue_head_t wq; /* Wait queue used by file->poll() */ wait_queue_head_t poll_wait; /* List of ready file descriptors */ struct list_head rdllist; /* RB tree root used to store monitored fd structs */ struct rb_root rbr; /* * This is a single linked list that chains all the "struct epitem" that * happened while transferring ready events to userspace w/out * holding ->lock. */ struct epitem *ovflist; /* wakeup_source used when ep_scan_ready_list is running */ struct wakeup_source *ws; /* The user that created the eventpoll descriptor */ struct user_struct *user; struct file *file; /* used to optimize loop detection check */ int visited; struct list_head visited_list_link; }; /* Wait structure used by the poll hooks */ struct eppoll_entry { /* List header used to link this structure to the "struct epitem" */ struct list_head llink; /* The "base" pointer is set to the container "struct epitem" */ struct epitem *base; /* * Wait queue item that will be linked to the target file wait * queue head. */ wait_queue_t wait; /* The wait queue head that linked the "wait" wait queue item */ wait_queue_head_t *whead; }; /* Wrapper struct used by poll queueing */ struct ep_pqueue { poll_table pt; struct epitem *epi; }; /* Used by the ep_send_events() function as callback private data */ struct ep_send_events_data { int maxevents; struct epoll_event __user *events; }; /* * Configuration options available inside /proc/sys/fs/epoll/ */ /* Maximum number of epoll watched descriptors, per user */ static long max_user_watches __read_mostly; /* * This mutex is used to serialize ep_free() and eventpoll_release_file(). */ static DEFINE_MUTEX(epmutex); /* Used to check for epoll file descriptor inclusion loops */ static struct nested_calls poll_loop_ncalls; /* Used for safe wake up implementation */ static struct nested_calls poll_safewake_ncalls; /* Used to call file's f_op->poll() under the nested calls boundaries */ static struct nested_calls poll_readywalk_ncalls; /* Slab cache used to allocate "struct epitem" */ static struct kmem_cache *epi_cache __read_mostly; /* Slab cache used to allocate "struct eppoll_entry" */ static struct kmem_cache *pwq_cache __read_mostly; /* Visited nodes during ep_loop_check(), so we can unset them when we finish */ static LIST_HEAD(visited_list); /* * List of files with newly added links, where we may need to limit the number * of emanating paths. Protected by the epmutex. */ static LIST_HEAD(tfile_check_list); #ifdef CONFIG_SYSCTL #include <linux/sysctl.h> static long zero; static long long_max = LONG_MAX; ctl_table epoll_table[] = { { .procname = "max_user_watches", .data = &max_user_watches, .maxlen = sizeof(max_user_watches), .mode = 0644, .proc_handler = proc_doulongvec_minmax, .extra1 = &zero, .extra2 = &long_max, }, { } }; #endif /* CONFIG_SYSCTL */ static const struct file_operations eventpoll_fops; static inline int is_file_epoll(struct file *f) { return f->f_op == &eventpoll_fops; } /* Setup the structure that is used as key for the RB tree */ static inline void ep_set_ffd(struct epoll_filefd *ffd, struct file *file, int fd) { ffd->file = file; ffd->fd = fd; } /* Compare RB tree keys */ static inline int ep_cmp_ffd(struct epoll_filefd *p1, struct epoll_filefd *p2) { return (p1->file > p2->file ? +1: (p1->file < p2->file ? -1 : p1->fd - p2->fd)); } /* Tells us if the item is currently linked */ static inline int ep_is_linked(struct list_head *p) { return !list_empty(p); } static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_t *p) { return container_of(p, struct eppoll_entry, wait); } /* Get the "struct epitem" from a wait queue pointer */ static inline struct epitem *ep_item_from_wait(wait_queue_t *p) { return container_of(p, struct eppoll_entry, wait)->base; } /* Get the "struct epitem" from an epoll queue wrapper */ static inline struct epitem *ep_item_from_epqueue(poll_table *p) { return container_of(p, struct ep_pqueue, pt)->epi; } /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ static inline int ep_op_has_event(int op) { return op != EPOLL_CTL_DEL; } /* Initialize the poll safe wake up structure */ static void ep_nested_calls_init(struct nested_calls *ncalls) { INIT_LIST_HEAD(&ncalls->tasks_call_list); spin_lock_init(&ncalls->lock); } /** * ep_events_available - Checks if ready events might be available. * * @ep: Pointer to the eventpoll context. * * Returns: Returns a value different than zero if ready events are available, * or zero otherwise. */ static inline int ep_events_available(struct eventpoll *ep) { return !list_empty(&ep->rdllist) || ep->ovflist != EP_UNACTIVE_PTR; } /** * ep_call_nested - Perform a bound (possibly) nested call, by checking * that the recursion limit is not exceeded, and that * the same nested call (by the meaning of same cookie) is * no re-entered. * * @ncalls: Pointer to the nested_calls structure to be used for this call. * @max_nests: Maximum number of allowed nesting calls. * @nproc: Nested call core function pointer. * @priv: Opaque data to be passed to the @nproc callback. * @cookie: Cookie to be used to identify this nested call. * @ctx: This instance context. * * Returns: Returns the code returned by the @nproc callback, or -1 if * the maximum recursion limit has been exceeded. */ static int ep_call_nested(struct nested_calls *ncalls, int max_nests, int (*nproc)(void *, void *, int), void *priv, void *cookie, void *ctx) { int error, call_nests = 0; unsigned long flags; struct list_head *lsthead = &ncalls->tasks_call_list; struct nested_call_node *tncur; struct nested_call_node tnode; spin_lock_irqsave(&ncalls->lock, flags); /* * Try to see if the current task is already inside this wakeup call. * We use a list here, since the population inside this set is always * very much limited. */ list_for_each_entry(tncur, lsthead, llink) { if (tncur->ctx == ctx && (tncur->cookie == cookie || ++call_nests > max_nests)) { /* * Ops ... loop detected or maximum nest level reached. * We abort this wake by breaking the cycle itself. */ error = -1; goto out_unlock; } } /* Add the current task and cookie to the list */ tnode.ctx = ctx; tnode.cookie = cookie; list_add(&tnode.llink, lsthead); spin_unlock_irqrestore(&ncalls->lock, flags); /* Call the nested function */ error = (*nproc)(priv, cookie, call_nests); /* Remove the current task from the list */ spin_lock_irqsave(&ncalls->lock, flags); list_del(&tnode.llink); out_unlock: spin_unlock_irqrestore(&ncalls->lock, flags); return error; } /* * As described in commit 0ccf831cb lockdep: annotate epoll * the use of wait queues used by epoll is done in a very controlled * manner. Wake ups can nest inside each other, but are never done * with the same locking. For example: * * dfd = socket(...); * efd1 = epoll_create(); * efd2 = epoll_create(); * epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...); * epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...); * * When a packet arrives to the device underneath "dfd", the net code will * issue a wake_up() on its poll wake list. Epoll (efd1) has installed a * callback wakeup entry on that queue, and the wake_up() performed by the * "dfd" net code will end up in ep_poll_callback(). At this point epoll * (efd1) notices that it may have some event ready, so it needs to wake up * the waiters on its poll wait list (efd2). So it calls ep_poll_safewake() * that ends up in another wake_up(), after having checked about the * recursion constraints. That are, no more than EP_MAX_POLLWAKE_NESTS, to * avoid stack blasting. * * When CONFIG_DEBUG_LOCK_ALLOC is enabled, make sure lockdep can handle * this special case of epoll. */ #ifdef CONFIG_DEBUG_LOCK_ALLOC static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { unsigned long flags; spin_lock_irqsave_nested(&wqueue->lock, flags, subclass); wake_up_locked_poll(wqueue, events); spin_unlock_irqrestore(&wqueue->lock, flags); } #else static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { wake_up_poll(wqueue, events); } #endif static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests) { ep_wake_up_nested((wait_queue_head_t *) cookie, POLLIN, 1 + call_nests); return 0; } /* * Perform a safe wake up of the poll wait list. The problem is that * with the new callback'd wake up system, it is possible that the


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