Meaning receive multiple messages, reducing the number of syscalls and
net stack entry/exit operations.
Next patches will introduce mechanisms where protocols that want to
optimize this operation will provide an unlocked_recvmsg operation.
This takes into account comments made by:
. Paul Moore: sock_recvmsg is called only for the first datagram,
sock_recvmsg_nosec is used for the rest.
. Caitlin Bestler: recvmmsg now has a struct timespec timeout, that
works in the same fashion as the ppoll one.
If the underlying protocol returns a datagram with MSG_OOB set, this
will make recvmmsg return right away with as many datagrams (+ the OOB
one) it has received so far.
. Rémi Denis-Courmont & Steven Whitehouse: If we receive N < vlen
datagrams and then recvmsg returns an error, recvmmsg will return
the successfully received datagrams, store the error and return it
in the next call.
This paves the way for a subsequent optimization, sk_prot->unlocked_recvmsg,
where we will be able to acquire the lock only at batch start and end, not at
every underlying recvmsg call.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits)
powerpc64: convert to dynamic percpu allocator
sparc64: use embedding percpu first chunk allocator
percpu: kill lpage first chunk allocator
x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA
percpu: update embedding first chunk allocator to handle sparse units
percpu: use group information to allocate vmap areas sparsely
vmalloc: implement pcpu_get_vm_areas()
vmalloc: separate out insert_vmalloc_vm()
percpu: add chunk->base_addr
percpu: add pcpu_unit_offsets[]
percpu: introduce pcpu_alloc_info and pcpu_group_info
percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward
percpu: add @align to pcpu_fc_alloc_fn_t
percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()
percpu: drop @static_size from first chunk allocators
percpu: generalize first chunk allocator selection
percpu: build first chunk allocators selectively
percpu: rename 4k first chunk allocator to page
percpu: improve boot messages
percpu: fix pcpu_reclaim() locking
...
Fix trivial conflict as by Tejun Heo in kernel/sched.c
Add #inclusions of linux/tracehook.h to those arch files that had the tracehook
call for TIF_NOTIFY_RESUME added when support for that flag was added to that
arch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Implement TIF_NOTIFY_RESUME for most of those architectures in which isn't yet
available, and, whilst we're at it, have it call the appropriate tracehook.
After this patch, blackfin, m68k* and xtensa still lack support and need
alteration of assembly code to make it work.
Resume notification can then be used (by a later patch) to install a new
session keyring on the parent of a process.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
cc: linux-arch@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
Conflicts:
arch/sparc/kernel/smp_64.c
arch/x86/kernel/cpu/perf_counter.c
arch/x86/kernel/setup_percpu.c
drivers/cpufreq/cpufreq_ondemand.c
mm/percpu.c
Conflicts in core and arch percpu codes are mostly from commit
ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many
num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all
the first chunk allocators into mm/percpu.c, the changes are moved
from arch code to mm/percpu.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
Discarded sections in different archs share some commonality but have
considerable differences. This led to linker script for each arch
implementing its own /DISCARD/ definition, which makes maintaining
tedious and adding new entries error-prone.
This patch makes all linker scripts to move discard definitions to the
end of the linker script and use the common DISCARDS macro. As ld
uses the first matching section definition, archs can include default
discarded sections by including them earlier in the linker script.
ia64 is notable because it first throws away some ia64 specific
subsections and then include the rest of the sections into the final
image, so those sections must be discarded before the inclusion.
defconfig compile tested for x86, x86-64, powerpc, powerpc64, ia64,
alpha, sparc, sparc64 and s390. Michal Simek tested microblaze.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Tested-by: Michal Simek <monstr@monstr.eu>
Cc: linux-arch@vger.kernel.org
Cc: Michal Simek <monstr@monstr.eu>
Cc: microblaze-uclinux@itee.uq.edu.au
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Tony Luck <tony.luck@intel.com>
Commit 5fd29d6ccb ("printk: clean up
handling of log-levels and newlines") changed printk semantics. printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.
<level> is now included in the output on each additional use.
Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
x86 throws away .discard section but no other archs do. Also,
.discard is not thrown away while linking modules. Make every arch
and module linking throw it away. This will be used to define dummy
variables for percpu declarations and definitions.
This patch is based on Ivan Kokshaysky's alpha percpu patch.
[ Impact: always throw away everything in .discard ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
avr32, mn10300, parisc, s390, sh, xtensa:
They never set PT_DTRACE, but clear it after do_execve().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Chris Zankel <chris@zankel.net>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* create mm/init-mm.c, move init_mm there
* remove INIT_MM, initialize init_mm with C99 initializer
* unexport init_mm on all arches:
init_mm is already unexported on x86.
One strange place is some OMAP driver (drivers/video/omap/) which
won't build modular, but it's already wants get_vm_area() export.
Somebody should look there.
[akpm@linux-foundation.org: add missing #includes]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6:
avr32: Fix oops on unaligned user access
avr32: Add support for Mediama RMTx add-on board for ATNGW100
avr32: Change Atmel ATNGW100 config to add choice of add-on board
Fix MIMC200 board LCD init
avr32: Fix clash in ATMEL_USART_ flags
avr32: remove obsolete hw_interrupt_type
avr32: Solves problem with inverted MCI detect pin on Merisc board
atmel-mci: Add support for inverted detect pin
The unaligned address exception handler (and others) does not scan the
fixup tables before oopsing. This is bad because it means passing a
badly aligned pointer from user space might crash the kernel.
Fix this by scanning the fixup tables in _exception(). This should
resolve the issue for unaligned addresses as well as other less common
exceptions that might be happening during a userspace access. The page
fault handler already does fixup processing.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Everyone cut and paste this comment from my original one. We now do
it generically, so cut the comments.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Amerigo Wang <amwang@redhat.com>
Stephen Rothwell <sfr@canb.auug.org.au> writes:
> Today's linux-next build of at least some av32 and arm configs failed like this:
>
> arch/avr32/kernel/signal.c:216: error: conflicting types for 'restart_syscall'
> include/linux/sched.h:2184: error: previous definition of 'restart_syscall' was here
>
> Caused by commit 690cc3ffe3 ("syscall:
> Implement a convinience function restart_syscall") from the net tree.
Grrr. Some days it feels like all of the good names are already taken.
Let's just rename the two static users in arm and avr32 to get this
sorted out.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass clocksource pointer to the read() callback for clocksources. This
allows us to share the callback between multiple instances.
[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (32 commits)
x86: disable __do_IRQ support
sparseirq, powerpc/cell: fix unused variable warning in interrupt.c
genirq: deprecate obsolete typedefs and defines
genirq: deprecate __do_IRQ
genirq: add doc to struct irqaction
genirq: use kzalloc instead of explicit zero initialization
genirq: make irqreturn_t an enum
genirq: remove redundant if condition
genirq: remove unused hw_irq_controller typedef
irq: export remove_irq() and setup_irq() symbols
irq: match remove_irq() args with setup_irq()
irq: add remove_irq() for freeing of setup_irq() irqs
genirq: assert that irq handlers are indeed running in hardirq context
irq: name 'p' variables a bit better
irq: further clean up the free_irq() code flow
irq: refactor and clean up the free_irq() code flow
irq: clean up manage.c
irq: use GFP_KERNEL for action allocation in request_irq()
kernel/irq: fix sparse warning: make symbol static
irq: optimize init_kstat_irqs/init_copy_kstat_irqs
...
Replace handcoded rcall instructions with the call pseudo-instruction.
For kernels too far over 1MB the rcall instruction can't reach and
linking will fail. We already call the final linker with --relax which
converts call pseudo-instructions to the right things anyway.
This fixes
arch/avr32/kernel/built-in.o: In function `syscall_exit_work':
(.ex.text+0x198): relocation truncated to fit: R_AVR32_22H_PCREL against symbol `schedule' defined in .sched.text section in kernel/built-in.o
arch/avr32/kernel/built-in.o: In function `fault_exit_work':
(.ex.text+0x3b6): relocation truncated to fit: R_AVR32_22H_PCREL against symbol `schedule' defined in .sched.text section in kernel/built-in.o
But I'm still left with
arch/avr32/kernel/built-in.o:(.fixup+0x2): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+45a
arch/avr32/kernel/built-in.o:(.fixup+0x8): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+8ea
arch/avr32/kernel/built-in.o:(.fixup+0xe): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+abe
arch/avr32/kernel/built-in.o:(.fixup+0x14): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+ac8
arch/avr32/kernel/built-in.o:(.fixup+0x1a): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+ad2
arch/avr32/kernel/built-in.o:(.fixup+0x20): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+adc
arch/avr32/kernel/built-in.o:(.fixup+0x26): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+ae6
arch/avr32/kernel/built-in.o:(.fixup+0x2c): relocation truncated to fit: R_AVR32_22H_PCREL against `.text'+af0
arch/avr32/kernel/built-in.o:(.fixup+0x32): additional relocation overflows omitted from the output
These are caused by a similar problem with 'rjmp' instructions.
Unfortunately, there's no easy fix for these at the moment since we
don't have a arbitrary-range 'jmp' instruction similar to 'call'.
Signed-off-by: Ben Nizette <bn@niasdigital.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
While looking at reducing the amount of architecture namespace pollution
in the generic kernel, I found that asm/irq.h is included in the vast
majority of compilations on ARM (around 650 files.)
Since asm/irq.h includes a sub-architecture include file on ARM, this
causes a negative impact on the ccache's ability to re-use the build
results from other sub-architectures, so we have a desire to reduce the
dependencies on asm/irq.h.
It turns out that a major cause of this is the needless include of
linux/hardirq.h into asm-generic/local.h. The patch below removes this
include, resulting in some 250 to 300 files (around half) of the kernel
then omitting asm/irq.h.
My test builds still succeed, provided two ARM files are fixed
(arch/arm/kernel/traps.c and arch/arm/mm/fault.c) - so there may be
negative impacts for this on other architectures.
Note that x86 does not include asm/irq.h nor linux/hardirq.h in its
asm/local.h, so this patch can be viewed as bringing the generic version
into line with the x86 version.
[kosaki.motohiro@jp.fujitsu.com: add #include <linux/irqflags.h> to acpi/processor_idle.c]
[adobriyan@gmail.com: fix sparc64]
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits)
x86: export vector_used_by_percpu_irq
x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and()
sched: nominate preferred wakeup cpu, fix
x86: fix lguest used_vectors breakage, -v2
x86: fix warning in arch/x86/kernel/io_apic.c
sched: fix warning in kernel/sched.c
sched: move test_sd_parent() to an SMP section of sched.h
sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0
sched: activate active load balancing in new idle cpus
sched: bias task wakeups to preferred semi-idle packages
sched: nominate preferred wakeup cpu
sched: favour lower logical cpu number for sched_mc balance
sched: framework for sched_mc/smt_power_savings=N
sched: convert BALANCE_FOR_xx_POWER to inline functions
x86: use possible_cpus=NUM to extend the possible cpus allowed
x86: fix cpu_mask_to_apicid_and to include cpu_online_mask
x86: update io_apic.c to the new cpumask code
x86: Introduce topology_core_cpumask()/topology_thread_cpumask()
x86: xen: use smp_call_function_many()
x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c
...
Fixed up trivial conflict in kernel/time/tick-sched.c manually
Impact: change calling convention of existing clock_event APIs
struct clock_event_timer's cpumask field gets changed to take pointer,
as does the ->broadcast function.
Another single-patch change. For safety, we BUG_ON() in
clockevents_register_device() if it's not set.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Include <linux/pm.h> to see the declaration of pm_power_off, and remove
unneeded NULL initializer.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
While updating the rcu code, I noticed that do_nmi() for AVR32 is odd:
There is an nmi_enter() call without an nmi_exit().
This can't be correct, it breaks rcu (at least the preempt version) and
lockdep.
[haavard.skinnemoen@atmel.com: fixed another case that returned directly]
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
On AVR32, all parameters beyond the 5th are passed on the stack. System
calls don't use the stack -- they borrow a callee-saved register
instead. This means that syscalls that take 6 parameters must be called
through a stub that pushes the last parameter on the stack.
This patch adds a stub for sync_file_range syscall on AVR32
architecture. Tested with uClibc snapshot.
Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
This patch implements the generic_find_next_le_bit bit function for AVR32
architecture. This is used by EXT4 file system.
Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
When using the Java Extension Module hardware, a Java stack underflow or
overflow trap may cause the system to enter an infinite exception loop.
Although there's no kernel support for the Java hardware yet, we need to
be able to recover from this situation and keep the system running.
This patch adds code to detect and fixup this situation in the critical
exception handler and terminate the faulting process. We may have to
rethink how to handle this more gracefully when the necessary kernel
support for hardware-accelerated Java is added.
Reported-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Update all avr32-specific files to use the new platform-specific header
locations. Drivers shared with ARM are left alone for now.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
The following patch allows the avr32_comparator interrupt to be shared.
This is necessary as the avr32 oprofile driver shares the irq group 0
with the timer.
To make OProfile actually work on AVR32, a small patch for oprofiled is
also needed (posted to the oprofile mailing list).
Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
[haavard.skinnemoen@atmel.com: set IRQF_SHARED unconditionally]
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
nohz: adjust tick_nohz_stop_sched_tick() call of s390 as well
nohz: prevent tick stop outside of the idle loop
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
arch/mips/kernel/stacktrace.c: Heiko can't type
kthread: reduce stack pressure in create_kthread and kthreadd
fix core/stacktrace changes on avr32, mips, sh
This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.
I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.
I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.
Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:
scheduler switch to idle task
enable interrupts
Window starts here
----> interrupt happens (does not set NEED_RESCHED)
irq_exit() stops the tick
----> interrupt happens (does set NEED_RESCHED)
return from schedule()
cpu_idle(): preempt_disable();
Window ends here
The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.
The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.
Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.
cpu_idle()
{
preempt_disable();
while(1) {
tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
are in the idle loop
while (!need_resched())
halt();
tick_nohz_restart_sched_tick(); <- disables NOHZ mode
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
In hindsight we should have done this forever, but ...
/me grabs a large brown paperbag.
Debugged-by: Jack Ren <jack.ren@marvell.com>,
Debugged-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fixes this type of problem:
CC arch/s390/kernel/stacktrace.o
arch/s390/kernel/stacktrace.c:84: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:84: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:84: warning: parameter names (without types) in function declaration
arch/s390/kernel/stacktrace.c:97: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:97: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:97: warning: parameter names (without types) in function declaration
caused by "stacktrace: export save_stack_trace[_tsk]"
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew Morton reported this against linux-next:
ERROR: ".save_stack_trace" [tests/backtracetest.ko] undefined!
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Expand the per-process PGDs so that they cover the kernel virtual
memory area as well. This simplifies the TLB miss handler fastpath
since it doesn't have to check for kernel addresses anymore.
If a TLB miss happens on a kernel address and a second-level page
table can't be found, we check swapper_pg_dir and copy the PGD entry
into the user PGD if it can be found there.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Instead of storing physical addresses along with page flags in the
PGD, store virtual addresses and use NULL to indicate a not present
second-level page table. A non-page-aligned page table indicates a bad
PMD.
This simplifies the TLB miss handler since it no longer has to check
the Present bit and no longer has to convert the PGD entry from
physical to virtual address. Instead, it has to check for a NULL
entry, which is slightly cheaper than either.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Kill the special exception handler sections .tlbx.ex.text,
.tlbr.ex.text, tlbw.ex.text and .scall.text. Use .org instead to place
the handlers at the required offsets from EVBA.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
