2005-04-16 22:20:36 +00:00
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/*
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* arch/s390/kernel/process.c
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Hartmut Penner (hp@de.ibm.com),
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* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
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*
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* Derived from "arch/i386/kernel/process.c"
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* Copyright (C) 1995, Linus Torvalds
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <linux/compiler.h>
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/irq.h>
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#include <asm/timer.h>
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2006-09-28 14:56:43 +00:00
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asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
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2005-04-16 22:20:36 +00:00
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/*
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* Return saved PC of a blocked thread. used in kernel/sched.
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* resume in entry.S does not create a new stack frame, it
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* just stores the registers %r6-%r15 to the frame given by
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* schedule. We want to return the address of the caller of
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* schedule, so we have to walk the backchain one time to
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* find the frame schedule() store its return address.
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*/
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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2006-01-14 21:20:57 +00:00
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struct stack_frame *sf, *low, *high;
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2005-04-16 22:20:36 +00:00
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2006-01-14 21:20:57 +00:00
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if (!tsk || !task_stack_page(tsk))
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return 0;
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low = task_stack_page(tsk);
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high = (struct stack_frame *) task_pt_regs(tsk);
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sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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2005-04-16 22:20:36 +00:00
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return sf->gprs[8];
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}
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/*
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* Need to know about CPUs going idle?
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*/
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[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 09:16:30 +00:00
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static ATOMIC_NOTIFIER_HEAD(idle_chain);
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2005-04-16 22:20:36 +00:00
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int register_idle_notifier(struct notifier_block *nb)
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{
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[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 09:16:30 +00:00
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return atomic_notifier_chain_register(&idle_chain, nb);
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2005-04-16 22:20:36 +00:00
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}
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EXPORT_SYMBOL(register_idle_notifier);
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int unregister_idle_notifier(struct notifier_block *nb)
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{
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[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 09:16:30 +00:00
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return atomic_notifier_chain_unregister(&idle_chain, nb);
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2005-04-16 22:20:36 +00:00
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}
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EXPORT_SYMBOL(unregister_idle_notifier);
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void do_monitor_call(struct pt_regs *regs, long interruption_code)
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{
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/* disable monitor call class 0 */
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__ctl_clear_bit(8, 15);
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2007-07-10 09:24:21 +00:00
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atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
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(void *)(long) smp_processor_id());
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2005-04-16 22:20:36 +00:00
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}
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2005-06-25 21:55:30 +00:00
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extern void s390_handle_mcck(void);
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2005-04-16 22:20:36 +00:00
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/*
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* The idle loop on a S390...
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*/
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2006-03-24 11:15:57 +00:00
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static void default_idle(void)
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2005-04-16 22:20:36 +00:00
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{
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int cpu, rc;
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[PATCH] sched: resched and cpu_idle rework
Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid. Improves efficiency of
resched_task and some cpu_idle routines.
* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
and as we hold it during resched_task, then there is no need for an
atomic test and set there. The only other time this should be set is
when the task's quantum expires, in the timer interrupt - this is
protected against because the rq lock is irq-safe.
- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
won't get unset until the task get's schedule()d off.
- If we are running on the same CPU as the task we resched, then set
TIF_NEED_RESCHED and no further action is required.
- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
after TIF_NEED_RESCHED has been set, then we need to send an IPI.
Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.
* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
becomes true, explicitly call schedule(). This makes things a bit clearer
(IMO), but haven't updated all architectures yet.
- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
to the resched_task rules, this isn't needed (and actually breaks the
assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
held). So remove that. Generally one less locked memory op when switching
to the idle thread.
- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
most polling idle loops. The above resched_task semantics allow it to be
set until before the last time need_resched() is checked before going into
a halt requiring interrupt wakeup.
Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
can be always left set, completely eliminating resched IPIs when rescheduling
the idle task.
POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 05:39:04 +00:00
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/* CPU is going idle. */
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cpu = smp_processor_id();
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2005-04-16 22:20:36 +00:00
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|
|
local_irq_disable();
|
[PATCH] sched: resched and cpu_idle rework
Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid. Improves efficiency of
resched_task and some cpu_idle routines.
* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
and as we hold it during resched_task, then there is no need for an
atomic test and set there. The only other time this should be set is
when the task's quantum expires, in the timer interrupt - this is
protected against because the rq lock is irq-safe.
- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
won't get unset until the task get's schedule()d off.
- If we are running on the same CPU as the task we resched, then set
TIF_NEED_RESCHED and no further action is required.
- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
after TIF_NEED_RESCHED has been set, then we need to send an IPI.
Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.
* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
becomes true, explicitly call schedule(). This makes things a bit clearer
(IMO), but haven't updated all architectures yet.
- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
to the resched_task rules, this isn't needed (and actually breaks the
assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
held). So remove that. Generally one less locked memory op when switching
to the idle thread.
- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
most polling idle loops. The above resched_task semantics allow it to be
set until before the last time need_resched() is checked before going into
a halt requiring interrupt wakeup.
Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
can be always left set, completely eliminating resched IPIs when rescheduling
the idle task.
POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 05:39:04 +00:00
|
|
|
if (need_resched()) {
|
2005-04-16 22:20:36 +00:00
|
|
|
local_irq_enable();
|
[PATCH] sched: resched and cpu_idle rework
Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid. Improves efficiency of
resched_task and some cpu_idle routines.
* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
and as we hold it during resched_task, then there is no need for an
atomic test and set there. The only other time this should be set is
when the task's quantum expires, in the timer interrupt - this is
protected against because the rq lock is irq-safe.
- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
won't get unset until the task get's schedule()d off.
- If we are running on the same CPU as the task we resched, then set
TIF_NEED_RESCHED and no further action is required.
- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
after TIF_NEED_RESCHED has been set, then we need to send an IPI.
Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.
* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
becomes true, explicitly call schedule(). This makes things a bit clearer
(IMO), but haven't updated all architectures yet.
- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
to the resched_task rules, this isn't needed (and actually breaks the
assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
held). So remove that. Generally one less locked memory op when switching
to the idle thread.
- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
most polling idle loops. The above resched_task semantics allow it to be
set until before the last time need_resched() is checked before going into
a halt requiring interrupt wakeup.
Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
can be always left set, completely eliminating resched IPIs when rescheduling
the idle task.
POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 05:39:04 +00:00
|
|
|
return;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 09:16:30 +00:00
|
|
|
rc = atomic_notifier_call_chain(&idle_chain,
|
2007-07-10 09:24:21 +00:00
|
|
|
S390_CPU_IDLE, (void *)(long) cpu);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
|
|
|
|
BUG();
|
|
|
|
if (rc != NOTIFY_OK) {
|
|
|
|
local_irq_enable();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* enable monitor call class 0 */
|
|
|
|
__ctl_set_bit(8, 15);
|
|
|
|
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
2006-02-17 21:52:46 +00:00
|
|
|
if (cpu_is_offline(cpu)) {
|
|
|
|
preempt_enable_no_resched();
|
2005-04-16 22:20:36 +00:00
|
|
|
cpu_die();
|
2006-02-17 21:52:46 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif
|
|
|
|
|
2005-06-25 21:55:30 +00:00
|
|
|
local_mcck_disable();
|
|
|
|
if (test_thread_flag(TIF_MCCK_PENDING)) {
|
|
|
|
local_mcck_enable();
|
|
|
|
local_irq_enable();
|
|
|
|
s390_handle_mcck();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2006-07-03 07:24:46 +00:00
|
|
|
trace_hardirqs_on();
|
2005-06-25 21:55:30 +00:00
|
|
|
/* Wait for external, I/O or machine check interrupt. */
|
2007-02-05 20:18:17 +00:00
|
|
|
__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
|
2005-06-25 21:55:30 +00:00
|
|
|
PSW_MASK_IO | PSW_MASK_EXT);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
void cpu_idle(void)
|
|
|
|
{
|
2005-11-09 05:39:01 +00:00
|
|
|
for (;;) {
|
|
|
|
while (!need_resched())
|
|
|
|
default_idle();
|
|
|
|
|
|
|
|
preempt_enable_no_resched();
|
|
|
|
schedule();
|
|
|
|
preempt_disable();
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
void show_regs(struct pt_regs *regs)
|
|
|
|
{
|
|
|
|
struct task_struct *tsk = current;
|
|
|
|
|
2006-01-12 09:05:50 +00:00
|
|
|
printk("CPU: %d %s\n", task_thread_info(tsk)->cpu, print_tainted());
|
2005-04-16 22:20:36 +00:00
|
|
|
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
|
|
|
|
current->comm, current->pid, (void *) tsk,
|
|
|
|
(void *) tsk->thread.ksp);
|
|
|
|
|
|
|
|
show_registers(regs);
|
|
|
|
/* Show stack backtrace if pt_regs is from kernel mode */
|
|
|
|
if (!(regs->psw.mask & PSW_MASK_PSTATE))
|
2006-07-12 14:41:55 +00:00
|
|
|
show_trace(NULL, (unsigned long *) regs->gprs[15]);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
extern void kernel_thread_starter(void);
|
|
|
|
|
2006-09-28 14:56:43 +00:00
|
|
|
asm(
|
|
|
|
".align 4\n"
|
2005-04-16 22:20:36 +00:00
|
|
|
"kernel_thread_starter:\n"
|
|
|
|
" la 2,0(10)\n"
|
|
|
|
" basr 14,9\n"
|
|
|
|
" la 2,0\n"
|
|
|
|
" br 11\n");
|
|
|
|
|
|
|
|
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
|
|
|
|
{
|
|
|
|
struct pt_regs regs;
|
|
|
|
|
|
|
|
memset(®s, 0, sizeof(regs));
|
2007-02-05 20:18:17 +00:00
|
|
|
regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
|
2005-04-16 22:20:36 +00:00
|
|
|
regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
|
|
|
|
regs.gprs[9] = (unsigned long) fn;
|
|
|
|
regs.gprs[10] = (unsigned long) arg;
|
|
|
|
regs.gprs[11] = (unsigned long) do_exit;
|
|
|
|
regs.orig_gpr2 = -1;
|
|
|
|
|
|
|
|
/* Ok, create the new process.. */
|
|
|
|
return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
|
|
|
|
0, ®s, 0, NULL, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Free current thread data structures etc..
|
|
|
|
*/
|
|
|
|
void exit_thread(void)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
void flush_thread(void)
|
|
|
|
{
|
|
|
|
clear_used_math();
|
|
|
|
clear_tsk_thread_flag(current, TIF_USEDFPU);
|
|
|
|
}
|
|
|
|
|
|
|
|
void release_thread(struct task_struct *dead_task)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
|
|
|
|
unsigned long unused,
|
|
|
|
struct task_struct * p, struct pt_regs * regs)
|
|
|
|
{
|
|
|
|
struct fake_frame
|
|
|
|
{
|
|
|
|
struct stack_frame sf;
|
|
|
|
struct pt_regs childregs;
|
|
|
|
} *frame;
|
|
|
|
|
2006-01-12 09:05:49 +00:00
|
|
|
frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
|
2005-04-16 22:20:36 +00:00
|
|
|
p->thread.ksp = (unsigned long) frame;
|
|
|
|
/* Store access registers to kernel stack of new process. */
|
|
|
|
frame->childregs = *regs;
|
|
|
|
frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
|
|
|
|
frame->childregs.gprs[15] = new_stackp;
|
|
|
|
frame->sf.back_chain = 0;
|
|
|
|
|
|
|
|
/* new return point is ret_from_fork */
|
|
|
|
frame->sf.gprs[8] = (unsigned long) ret_from_fork;
|
|
|
|
|
|
|
|
/* fake return stack for resume(), don't go back to schedule */
|
|
|
|
frame->sf.gprs[9] = (unsigned long) frame;
|
|
|
|
|
|
|
|
/* Save access registers to new thread structure. */
|
|
|
|
save_access_regs(&p->thread.acrs[0]);
|
|
|
|
|
2006-01-06 08:19:28 +00:00
|
|
|
#ifndef CONFIG_64BIT
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* save fprs to current->thread.fp_regs to merge them with
|
|
|
|
* the emulated registers and then copy the result to the child.
|
|
|
|
*/
|
|
|
|
save_fp_regs(¤t->thread.fp_regs);
|
|
|
|
memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
|
|
|
|
sizeof(s390_fp_regs));
|
|
|
|
p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
|
|
|
|
/* Set a new TLS ? */
|
|
|
|
if (clone_flags & CLONE_SETTLS)
|
|
|
|
p->thread.acrs[0] = regs->gprs[6];
|
2006-01-06 08:19:28 +00:00
|
|
|
#else /* CONFIG_64BIT */
|
2005-04-16 22:20:36 +00:00
|
|
|
/* Save the fpu registers to new thread structure. */
|
|
|
|
save_fp_regs(&p->thread.fp_regs);
|
|
|
|
p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
|
|
|
|
/* Set a new TLS ? */
|
|
|
|
if (clone_flags & CLONE_SETTLS) {
|
|
|
|
if (test_thread_flag(TIF_31BIT)) {
|
|
|
|
p->thread.acrs[0] = (unsigned int) regs->gprs[6];
|
|
|
|
} else {
|
|
|
|
p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
|
|
|
|
p->thread.acrs[1] = (unsigned int) regs->gprs[6];
|
|
|
|
}
|
|
|
|
}
|
2006-01-06 08:19:28 +00:00
|
|
|
#endif /* CONFIG_64BIT */
|
2005-04-16 22:20:36 +00:00
|
|
|
/* start new process with ar4 pointing to the correct address space */
|
|
|
|
p->thread.mm_segment = get_fs();
|
|
|
|
/* Don't copy debug registers */
|
|
|
|
memset(&p->thread.per_info,0,sizeof(p->thread.per_info));
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-04-27 14:01:40 +00:00
|
|
|
asmlinkage long sys_fork(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-04-27 14:01:40 +00:00
|
|
|
struct pt_regs *regs = task_pt_regs(current);
|
|
|
|
return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2007-04-27 14:01:40 +00:00
|
|
|
asmlinkage long sys_clone(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-04-27 14:01:40 +00:00
|
|
|
struct pt_regs *regs = task_pt_regs(current);
|
|
|
|
unsigned long clone_flags;
|
|
|
|
unsigned long newsp;
|
2005-04-16 22:20:36 +00:00
|
|
|
int __user *parent_tidptr, *child_tidptr;
|
|
|
|
|
2007-04-27 14:01:40 +00:00
|
|
|
clone_flags = regs->gprs[3];
|
|
|
|
newsp = regs->orig_gpr2;
|
|
|
|
parent_tidptr = (int __user *) regs->gprs[4];
|
|
|
|
child_tidptr = (int __user *) regs->gprs[5];
|
|
|
|
if (!newsp)
|
|
|
|
newsp = regs->gprs[15];
|
|
|
|
return do_fork(clone_flags, newsp, regs, 0,
|
2005-04-16 22:20:36 +00:00
|
|
|
parent_tidptr, child_tidptr);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This is trivial, and on the face of it looks like it
|
|
|
|
* could equally well be done in user mode.
|
|
|
|
*
|
|
|
|
* Not so, for quite unobvious reasons - register pressure.
|
|
|
|
* In user mode vfork() cannot have a stack frame, and if
|
|
|
|
* done by calling the "clone()" system call directly, you
|
|
|
|
* do not have enough call-clobbered registers to hold all
|
|
|
|
* the information you need.
|
|
|
|
*/
|
2007-04-27 14:01:40 +00:00
|
|
|
asmlinkage long sys_vfork(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-04-27 14:01:40 +00:00
|
|
|
struct pt_regs *regs = task_pt_regs(current);
|
2005-04-16 22:20:36 +00:00
|
|
|
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
|
2007-04-27 14:01:40 +00:00
|
|
|
regs->gprs[15], regs, 0, NULL, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
asmlinkage void execve_tail(void)
|
|
|
|
{
|
|
|
|
task_lock(current);
|
|
|
|
current->ptrace &= ~PT_DTRACE;
|
|
|
|
task_unlock(current);
|
|
|
|
current->thread.fp_regs.fpc = 0;
|
|
|
|
if (MACHINE_HAS_IEEE)
|
|
|
|
asm volatile("sfpc %0,%0" : : "d" (0));
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* sys_execve() executes a new program.
|
|
|
|
*/
|
2007-04-27 14:01:40 +00:00
|
|
|
asmlinkage long sys_execve(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-04-27 14:01:40 +00:00
|
|
|
struct pt_regs *regs = task_pt_regs(current);
|
|
|
|
char *filename;
|
|
|
|
unsigned long result;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
filename = getname((char __user *) regs->orig_gpr2);
|
|
|
|
if (IS_ERR(filename)) {
|
|
|
|
result = PTR_ERR(filename);
|
|
|
|
goto out;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2007-04-27 14:01:40 +00:00
|
|
|
rc = do_execve(filename, (char __user * __user *) regs->gprs[3],
|
|
|
|
(char __user * __user *) regs->gprs[4], regs);
|
|
|
|
if (rc) {
|
|
|
|
result = rc;
|
|
|
|
goto out_putname;
|
|
|
|
}
|
|
|
|
execve_tail();
|
|
|
|
result = regs->gprs[2];
|
|
|
|
out_putname:
|
|
|
|
putname(filename);
|
2005-04-16 22:20:36 +00:00
|
|
|
out:
|
2007-04-27 14:01:40 +00:00
|
|
|
return result;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* fill in the FPU structure for a core dump.
|
|
|
|
*/
|
|
|
|
int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
|
|
|
|
{
|
2006-01-06 08:19:28 +00:00
|
|
|
#ifndef CONFIG_64BIT
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* save fprs to current->thread.fp_regs to merge them with
|
|
|
|
* the emulated registers and then copy the result to the dump.
|
|
|
|
*/
|
|
|
|
save_fp_regs(¤t->thread.fp_regs);
|
|
|
|
memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
|
2006-01-06 08:19:28 +00:00
|
|
|
#else /* CONFIG_64BIT */
|
2005-04-16 22:20:36 +00:00
|
|
|
save_fp_regs(fpregs);
|
2006-01-06 08:19:28 +00:00
|
|
|
#endif /* CONFIG_64BIT */
|
2005-04-16 22:20:36 +00:00
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned long get_wchan(struct task_struct *p)
|
|
|
|
{
|
|
|
|
struct stack_frame *sf, *low, *high;
|
|
|
|
unsigned long return_address;
|
|
|
|
int count;
|
|
|
|
|
2006-01-12 09:05:50 +00:00
|
|
|
if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
2006-01-12 09:05:50 +00:00
|
|
|
low = task_stack_page(p);
|
|
|
|
high = (struct stack_frame *) task_pt_regs(p);
|
2005-04-16 22:20:36 +00:00
|
|
|
sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
|
|
|
|
if (sf <= low || sf > high)
|
|
|
|
return 0;
|
|
|
|
for (count = 0; count < 16; count++) {
|
|
|
|
sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
|
|
|
|
if (sf <= low || sf > high)
|
|
|
|
return 0;
|
|
|
|
return_address = sf->gprs[8] & PSW_ADDR_INSN;
|
|
|
|
if (!in_sched_functions(return_address))
|
|
|
|
return return_address;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|