The purpose of this single series of commits from Srivatsa S Bhat (with
a small piece from Gautham R Shenoy) touching multiple subsystems that use
CPU hotplug notifiers is to provide a way to register them that will not
lead to deadlocks with CPU online/offline operations as described in the
changelog of commit 93ae4f978c (CPU hotplug: Provide lockless versions
of callback registration functions).
The first three commits in the series introduce the API and document it
and the rest simply goes through the users of CPU hotplug notifiers and
converts them to using the new method.
/
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Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
"The purpose of this single series of commits from Srivatsa S Bhat
(with a small piece from Gautham R Shenoy) touching multiple
subsystems that use CPU hotplug notifiers is to provide a way to
register them that will not lead to deadlocks with CPU online/offline
operations as described in the changelog of commit 93ae4f978c ("CPU
hotplug: Provide lockless versions of callback registration
functions").
The first three commits in the series introduce the API and document
it and the rest simply goes through the users of CPU hotplug notifiers
and converts them to using the new method"
* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
net/iucv/iucv.c: Fix CPU hotplug callback registration
net/core/flow.c: Fix CPU hotplug callback registration
mm, zswap: Fix CPU hotplug callback registration
mm, vmstat: Fix CPU hotplug callback registration
profile: Fix CPU hotplug callback registration
trace, ring-buffer: Fix CPU hotplug callback registration
xen, balloon: Fix CPU hotplug callback registration
hwmon, via-cputemp: Fix CPU hotplug callback registration
hwmon, coretemp: Fix CPU hotplug callback registration
thermal, x86-pkg-temp: Fix CPU hotplug callback registration
octeon, watchdog: Fix CPU hotplug callback registration
oprofile, nmi-timer: Fix CPU hotplug callback registration
intel-idle: Fix CPU hotplug callback registration
clocksource, dummy-timer: Fix CPU hotplug callback registration
drivers/base/topology.c: Fix CPU hotplug callback registration
acpi-cpufreq: Fix CPU hotplug callback registration
zsmalloc: Fix CPU hotplug callback registration
scsi, fcoe: Fix CPU hotplug callback registration
scsi, bnx2fc: Fix CPU hotplug callback registration
scsi, bnx2i: Fix CPU hotplug callback registration
...
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the vsyscall code in x86 by using this latter form of callback
registration.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch move the vsyscall_gtod_data handling out of vsyscall_64.c
into an additonal file vsyscall_gtod.c to make the functionality
available for x86 32 bit kernel.
It also adds a new vsyscall_32.c which setup the VVAR page.
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings. In any case, they are temporary and harmless.
This removes all the arch/x86 uses of the __cpuinit macros from
all C files. x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Pull security subsystem updates from James Morris:
"A quiet cycle for the security subsystem with just a few maintenance
updates."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: create a sysfs mount point for smackfs
Smack: use select not depends in Kconfig
Yama: remove locking from delete path
Yama: add RCU to drop read locking
drivers/char/tpm: remove tasklet and cleanup
KEYS: Use keyring_alloc() to create special keyrings
KEYS: Reduce initial permissions on keys
KEYS: Make the session and process keyrings per-thread
seccomp: Make syscall skipping and nr changes more consistent
key: Fix resource leak
keys: Fix unreachable code
KEYS: Add payload preparsing opportunity prior to key instantiate or update
This fixes two issues that could cause incompatibility between
kernel versions:
- If a tracer uses SECCOMP_RET_TRACE to select a syscall number
higher than the largest known syscall, emulate the unknown
vsyscall by returning -ENOSYS. (This is unlikely to make a
noticeable difference on x86-64 due to the way the system call
entry works.)
- On x86-64 with vsyscall=emulate, skipped vsyscalls were buggy.
This updates the documentation accordingly.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Will Drewry <wad@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Switch x86_64 to using sub-ns precise vsyscall
Cc: Tony Luck <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
To help migrate archtectures over to the new update_vsyscall method,
redfine CONFIG_GENERIC_TIME_VSYSCALL as CONFIG_GENERIC_TIME_VSYSCALL_OLD
Cc: Tony Luck <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Since users will need to include timekeeper_internal.h, move
update_vsyscall definitions to timekeeper_internal.h.
Cc: Tony Luck <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull debug-for-linus git tree from Ingo Molnar.
Fix up trivial conflict in arch/x86/kernel/cpu/perf_event_intel.c due to
a printk() having changed to a pr_info() differently in the two branches.
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Move call to print_modules() out of show_regs()
x86/mm: Mark free_initrd_mem() as __init
x86/microcode: Mark microcode_id[] as __initconst
x86/nmi: Clean up register_nmi_handler() usage
x86: Save cr2 in NMI in case NMIs take a page fault (for i386)
x86: Remove cmpxchg from i386 NMI nesting code
x86: Save cr2 in NMI in case NMIs take a page fault
x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
vsyscall_seccomp introduced a dependency on __secure_computing. On
configurations with CONFIG_SECCOMP disabled, compilation will fail.
Reported-by: feng xiangjun <fengxj325@gmail.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a seccomp filter program is installed, older static binaries and
distributions with older libc implementations (glibc 2.13 and earlier)
that rely on vsyscall use will be terminated regardless of the filter
program policy when executing time, gettimeofday, or getcpu. This is
only the case when vsyscall emulation is in use (vsyscall=emulate is the
default).
This patch emulates system call entry inside a vsyscall=emulate by
populating regs->ax and regs->orig_ax with the system call number prior
to calling into seccomp such that all seccomp-dependencies function
normally. Additionally, system call return behavior is emulated in line
with other vsyscall entrypoints for the trace/trap cases.
[ v2: fixed ip and sp on SECCOMP_RET_TRAP/TRACE (thanks to luto@mit.edu) ]
Reported-and-tested-by: Owen Kibel <qmewlo@gmail.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use a more current logging style:
- Bare printks should have a KERN_<LEVEL> for consistency's sake
- Add pr_fmt where appropriate
- Neaten some macro definitions
- Convert some Ok output to OK
- Use "%s: ", __func__ in pr_fmt for summit
- Convert some printks to pr_<level>
Message output is not identical in all cases.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: levinsasha928@gmail.com
Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop
[ merged two similar patches, tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 cleanups from Peter Anvin:
"The biggest textual change is the cleanup to use symbolic constants
for x86 trap values.
The only *functional* change and the reason for the x86/x32 dependency
is the move of is_ia32_task() into <asm/thread_info.h> so that it can
be used in other code that needs to understand if a system call comes
from the compat entry point (and therefore uses i386 system call
numbers) or not. One intended user for that is the BPF system call
filter. Moving it out of <asm/compat.h> means we can define it
unconditionally, returning always true on i386."
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Move is_ia32_task to asm/thread_info.h from asm/compat.h
x86: Rename trap_no to trap_nr in thread_struct
x86: Use enum instead of literals for trap values
Sigh, warnings are there for a reason.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: John Stultz <john.stultz@linaro.org>
We used to store the wall-to-monotonic offset and the realtime base.
It's faster to precompute the monotonic base.
This is about a 3% speedup on Sandy Bridge for CLOCK_MONOTONIC.
It's much more impressive for CLOCK_MONOTONIC_COARSE.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The update of the vdso data happens under xtime_lock, so adding a
nested lock is pointless. Just use a seqcount to sync the readers.
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Changing the sequence count in update_vsyscall_tz() is completely
pointless.
The vdso code copies the data unprotected. There is no point to change
this as sys_tz is nowhere protected at all. See sys_gettimeofday().
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
There are precedences of trap number being referred to as
trap_nr. However thread struct refers trap number as trap_no.
Change it to trap_nr.
Also use enum instead of left-over literals for trap values.
This is pure cleanup, no functional change intended.
Suggested-by: Ingo Molnar <mingo@eltu.hu>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120312092555.5379.942.sendpatchset@srdronam.in.ibm.com
[ Fixed the math-emu build ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This essentially reverts:
2b666859ec: x86: Default to vsyscall=native for now
The ABI breakage should now be fixed by:
commit 48c4206f5b02f28c4c78a1f5b491d3772fb64fb9
Author: Andy Lutomirski <luto@mit.edu>
Date: Thu Oct 20 08:48:19 2011 -0700
x86-64: Set siginfo and context on vsyscall emulation faults
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/93154af3b2b6d208906ae02d80d92cf60c6fa94f.1320712291.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To make this work, we teach the page fault handler how to send
signals on failed uaccess. This only works for user addresses
(kernel addresses will never hit the page fault handler in the
first place), so we need to generate signals for those
separately.
This gets the tricky case right: if the user buffer spans
multiple pages and only the second page is invalid, we set
cr2 and si_addr correctly. UML relies on this behavior to
"fault in" pages as needed.
We steal a bit from thread_info.uaccess_err to enable this.
Before this change, uaccess_err was a 32-bit boolean value.
This fixes issues with UML when vsyscall=emulate.
Reported-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4c8f91de7ec5cd2ef0f59521a04e1015f11e42b4.1320712291.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In removing the presence of <linux/module.h> from some of the
more common <linux/something.h> files, this implict include
of <linux/topology.h> was uncovered.
CC arch/x86/kernel/vsyscall_64.o
arch/x86/kernel/vsyscall_64.c: In function ‘vsyscall_set_cpu’:
arch/x86/kernel/vsyscall_64.c:259: error: implicit declaration of function ‘cpu_to_node’
Explicitly call it out so the cleanup can take place.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
This UML breakage:
linux-2.6.30.1[3800] vsyscall fault (exploit attempt?) ip:ffffffffff600000 cs:33 sp:7fbfb9c498 ax:ffffffffff600000 si:0 di:606790
linux-2.6.30.1[3856] vsyscall fault (exploit attempt?) ip:ffffffffff600000 cs:33 sp:7fbfb13168 ax:ffffffffff600000 si:0 di:606790
Is caused by commit 3ae36655 ("x86-64: Rework vsyscall emulation and add
vsyscall= parameter") - the vsyscall emulation code is not fully cooked
yet as UML relies on some rather fragile SIGSEGV semantics.
Linus suggested in https://lkml.org/lkml/2011/8/9/376 to default
to vsyscall=native for now, this patch implements that.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Andrew Lutomirski <luto@mit.edu>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20111005214047.GE14406@localhost.pp.htv.fi
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There are three choices:
vsyscall=native: Vsyscalls are native code that issues the
corresponding syscalls.
vsyscall=emulate (default): Vsyscalls are emulated by instruction
fault traps, tested in the bad_area path. The actual contents of
the vsyscall page is the same as the vsyscall=native case except
that it's marked NX. This way programs that make assumptions about
what the code in the page does will not be confused when they read
that code.
vsyscall=none: Trying to execute a vsyscall will segfault.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/8449fb3abf89851fd6b2260972666a6f82542284.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
As of commit 98d0ac38ca
Author: Andy Lutomirski <luto@mit.edu>
Date: Thu Jul 14 06:47:22 2011 -0400
x86-64: Move vread_tsc and vread_hpet into the vDSO
user code no longer directly calls into code in arch/x86/kernel/, so
we don't need compile flag hacks to make it safe. All vdso code is
in the vdso directory now.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/835cd05a4c7740544d09723d6ba48f4406f9826c.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Three places in the kernel assume that the only long mode CPL 3
selector is __USER_CS. This is not true on Xen -- Xen's sysretq
changes cs to the magic value 0xe033.
Two of the places are corner cases, but as of "x86-64: Improve
vsyscall emulation CS and RIP handling"
(c9712944b2), vsyscalls will segfault
if called with Xen's extra CS selector. This causes a panic when
older init builds die.
It seems impossible to make Xen use __USER_CS reliably without
taking a performance hit on every system call, so this fixes the
tests instead with a new paravirt op. It's a little ugly because
ptrace.h can't include paravirt.h.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/f4fcb3947340d9e96ce1054a432f183f9da9db83.1312378163.git.luto@mit.edu
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The vread field was bloating struct clocksource everywhere except
x86_64, and I want to change the way this works on x86_64, so let's
split it out into per-arch data.
Cc: x86@kernel.org
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: linux-ia64@vger.kernel.org
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/3ae5ec76a168eaaae63f08a2a1060b91aa0b7759.1310563276.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Three fixes here:
- Send SIGSEGV if called from compat code or with a funny CS.
- Don't BUG on impossible addresses.
- Add a missing local_irq_disable.
This patch also removes an unused variable.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/6fb2b13ab39b743d1e4f466eef13425854912f7f.1310563276.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
There's a fair amount of code in the vsyscall page. It contains
a syscall instruction (in the gettimeofday fallback) and who
knows what will happen if an exploit jumps into the middle of
some other code.
Reduce the risk by replacing the vsyscalls with short magic
incantations that cause the kernel to emulate the real
vsyscalls. These incantations are useless if entered in the
middle.
This causes vsyscalls to be a little more expensive than real
syscalls. Fortunately sensible programs don't use them.
The only exception is time() which is still called by glibc
through the vsyscall - but calling time() millions of times
per second is not sensible. glibc has this fixed in the
development tree.
This patch is not perfect: the vread_tsc and vread_hpet
functions are still at a fixed address. Fixing that might
involve making alternative patching work in the vDSO.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/e64e1b3c64858820d12c48fa739efbd1485e79d5.1307292171.git.luto@mit.edu
[ Removed the CONFIG option - it's simpler to just do it unconditionally. Tidied up the code as well. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It just segfaults since April 2008 (a4928cff), so I'm pretty
sure that nothing uses it. And having an empty section makes
the linker script a bit fragile.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/4a4abcf47ecadc269f2391a313576fe6d06acef7.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It's unnecessary overhead in code that's supposed to be highly
optimized. Removing it allows us to remove one of the two
syscall instructions in the vsyscall page.
The only sensible use for it is for UML users, and it doesn't
fully address inconsistent vsyscall results on UML. The real
fix for UML is to stop using vsyscalls entirely.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/973ae803fe76f712da4b2740e66dccf452d3b1e4.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move vvars out of the vsyscall page into their own page and mark
it NX.
Without this patch, an attacker who can force a daemon to call
some fixed address could wait until the time contains, say,
0xCD80, and then execute the current time.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/b1460f81dc4463d66ea3f2b5ce240f58d48effec.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: vdso: Remove unused variable
x86-64: Optimize vDSO time()
x86-64: Add time to vDSO
x86-64: Turn off -pg and turn on -foptimize-sibling-calls for vDSO
x86-64: Move vread_tsc into a new file with sensible options
x86-64: Vclock_gettime(CLOCK_MONOTONIC) can't ever see nsec < 0
x86-64: Don't generate cmov in vread_tsc
x86-64: Remove unnecessary barrier in vread_tsc
x86-64: Clean up vdso/kernel shared variables
All static seqlock should be initialized with the lockdep friendly
__SEQLOCK_UNLOCKED() macro.
Remove legacy SEQLOCK_UNLOCKED() macro.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/%3C1306238888.3026.31.camel%40edumazet-laptop%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Variables that are shared between the vdso and the kernel are
currently a bit of a mess. They are each defined with their own
magic, they are accessed differently in the kernel, the vsyscall page,
and the vdso, and one of them (vsyscall_clock) doesn't even really
exist.
This changes them all to use a common mechanism. All of them are
delcared in vvar.h with a fixed address (validated by the linker
script). In the kernel (as before), they look like ordinary
read-write variables. In the vsyscall page and the vdso, they are
accessed through a new macro VVAR, which gives read-only access.
The vdso is now loaded verbatim into memory without any fixups. As a
side bonus, access from the vdso is faster because a level of
indirection is removed.
While we're at it, pack jiffies and vgetcpu_mode into the same
cacheline.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Borislav Petkov <bp@amd64.org>
Link: http://lkml.kernel.org/r/%3C7357882fbb51fa30491636a7b6528747301b7ee9.1306156808.git.luto%40mit.edu%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
update_vsyscall() did not provide the wall_to_monotoinc offset,
so arch specific implementations tend to reference wall_to_monotonic
directly. This limits future cleanups in the timekeeping core, so
this patch fixes the update_vsyscall interface to provide
wall_to_monotonic, allowing wall_to_monotonic to be made static
as planned in Documentation/feature-removal-schedule.txt
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1279068988-21864-7-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Due to vtime calling vgettimeofday(), its possible that an application
could call time();create("stuff",O_RDRW); only to see the file's
creation timestamp to be before the value returned by time.
A similar way to reproduce the issue is to compare the vsyscall time()
with the syscall time(), and observe ordering issues.
The modified test case from Oleg Nesterov below can illustrate this:
int main(void)
{
time_t sec1,sec2;
do {
sec1 = time(&sec2);
sec2 = syscall(__NR_time, NULL);
} while (sec1 <= sec2);
printf("vtime: %d.000000\n", sec1);
printf("time: %d.000000\n", sec2);
return 0;
}
The proper fix is to make vtime use the same time value as
current_kernel_time() (which is exported via update_vsyscall) instead of
vgettime().
Thanks to Jiri Olsa for bringing up the issue and catching bugs in
earlier verisons of this fix.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
LKML-Reference: <1279068988-21864-2-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
KVM need vsyscall_init() to initialize MSR_TSC_AUX before it read the value.
Per Avi's suggestion, this patch raised vsyscall priority on hotplug notifier
chain, to 30.
CC: Ingo Molnar <mingo@elte.hu>
CC: linux-kernel@vger.kernel.org
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier
to struct timekeeper" the clock multiplier of vsyscall is updated with
the unmodified clock multiplier of the clock source and not with the
NTP adjusted multiplier of the timekeeper.
This causes user space observerable time warps:
new CLOCK-warp maximum: 120 nsecs, 00000025c337c537 -> 00000025c337c4bf
Add a new argument "mult" to update_vsyscall() and hand in the
timekeeping internal NTP adjusted multiplier.
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: "Zhang Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
It's unused.
It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.
It _was_ used in two places at arch/frv for some reason.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After talking with some application writers who want very fast, but not
fine-grained timestamps, I decided to try to implement new clock_ids
to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE
which returns the time at the last tick. This is very fast as we don't
have to access any hardware (which can be very painful if you're using
something like the acpi_pm clocksource), and we can even use the vdso
clock_gettime() method to avoid the syscall. The only trade off is you
only get low-res tick grained time resolution.
This isn't a new idea, I know Ingo has a patch in the -rt tree that made
the vsyscall gettimeofday() return coarse grained time when the
vsyscall64 sysctrl was set to 2. However this affects all applications
on a system.
With this method, applications can choose the proper speed/granularity
trade-off for themselves.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: nikolag@ca.ibm.com
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: arjan@infradead.org
Cc: jonathan@jonmasters.org
LKML-Reference: <1250734414.6897.5.camel@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The *fence instructions were moved to vsyscall_64.c by commit
cb9e35dce9. But this breaks the
vDSO, because vread methods are also called from there.
Besides, the synchronization might be unnecessary for other
time sources than TSC.
[ Impact: fix potential time warp in VDSO ]
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
LKML-Reference: <9d0ea9ea0f866bdc1f4d76831221ae117f11ea67.1243241859.git.ptesarik@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits)
sched, trace: update trace_sched_wakeup()
tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3
Revert "x86: disable X86_PTRACE_BTS"
ring-buffer: prevent false positive warning
ring-buffer: fix dangling commit race
ftrace: enable format arguments checking
x86, bts: memory accounting
x86, bts: add fork and exit handling
ftrace: introduce tracing_reset_online_cpus() helper
tracing: fix warnings in kernel/trace/trace_sched_switch.c
tracing: fix warning in kernel/trace/trace.c
tracing/ring-buffer: remove unused ring_buffer size
trace: fix task state printout
ftrace: add not to regex on filtering functions
trace: better use of stack_trace_enabled for boot up code
trace: add a way to enable or disable the stack tracer
x86: entry_64 - introduce FTRACE_ frame macro v2
tracing/ftrace: add the printk-msg-only option
tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()
x86, bts: correctly report invalid bts records
...
Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits
being already partly merged by the SH merge.
Impact: name change of unlikely tracer and profiler
Ingo Molnar suggested changing the config from UNLIKELY_PROFILE
to BRANCH_PROFILING. I never did like the "unlikely" name so I
went one step farther, and renamed all the unlikely configurations
to a "BRANCH" variant.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
