This implements new vDSO for x86-64. The concept is similar
to the existing vDSOs on i386 and PPC. x86-64 has had static
vsyscalls before, but these are not flexible enough anymore.
A vDSO is a ELF shared library supplied by the kernel that is mapped into
user address space. The vDSO mapping is randomized for each process
for security reasons.
Doing this was needed for clock_gettime, because clock_gettime
always needs a syscall fallback and having one at a fixed
address would have made buffer overflow exploits too easy to write.
The vdso can be disabled with vdso=0
It currently includes a new gettimeofday implemention and optimized
clock_gettime(). The gettimeofday implementation is slightly faster
than the one in the old vsyscall. clock_gettime is significantly faster
than the syscall for CLOCK_MONOTONIC and CLOCK_REALTIME.
The new calls are generally faster than the old vsyscall.
Advantages over the old x86-64 vsyscalls:
- Extensible
- Randomized
- Cleaner
- Easier to virtualize (the old static address range previously causes
overhead e.g. for Xen because it has to create special page tables for it)
Weak points:
- glibc support still to be written
The VM interface is partly based on Ingo Molnar's i386 version.
Includes compile fix from Joachim Deguara
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The vsyscall time() function basically returns the second portion of
xtime directly. This however means that there is about a ticks worth of
time each second where time() will return a second value less then what
gettimeofday() does.
Additionally, this window where vtime() is behind vgettimeofday() grows
when dynticks is enabled, so its probably good to get this in before
dynticks lands.
Big thanks to Sripathi for noticing this issue and creating a test case
to work with!
This patch changes the vtime() implemenation to call vgettimeofday(),
much as syscall time() implementation calls gettimeofday().
2.6.21 stable candidate too
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress. This
patch introduces such notifications and causes them to be used during
suspend and resume transitions. It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).
[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current vsyscall_gtod_data is large (3 or 4 cache lines dirtied at timer
interrupt). We can shrink it to exactly 64 bytes (1 cache line on AMD64)
Instead of copying a whole struct clocksource, we copy only needed fields.
I deleted an unused field : offset_base
This patch fixes one oddity in vgettimeofday(): It can returns a timeval with
tv_usec = 1000000. Maybe not a bug, but why not doing the right thing ?
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andi Kleen <ak@suse.de>
There is a tiny probability that the return value from vtime(time_t *t) is
Signed-off-by: Andi Kleen <ak@suse.de>
different than the value stored in *t
Using a temporary variable solves the problem and gives a faster code.
17: 48 85 ff test %rdi,%rdi
1a: 48 8b 05 00 00 00 00 mov 0(%rip),%rax #
__vsyscall_gtod_data.wall_time_tv.tv_sec
21: 74 03 je 26
23: 48 89 07 mov %rax,(%rdi)
26: c9 leaveq
27: c3 retq
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Currently __pa_symbol is for use with symbols in the kernel address
map and __pa is for use with pointers into the physical memory map.
But the code is implemented so you can usually interchange the two.
__pa which is much more common can be implemented much more cheaply
if it is it doesn't have to worry about any other kernel address
spaces. This is especially true with a relocatable kernel as
__pa_symbol needs to peform an extra variable read to resolve
the address.
There is a third macro that is added for the vsyscall data
__pa_vsymbol for finding the physical addesses of vsyscall pages.
Most of this patch is simply sorting through the references to
__pa or __pa_symbol and using the proper one. A little of
it is continuing to use a physical address when we have it
instead of recalculating it several times.
swapper_pgd is now NULL. leave_mm now uses init_mm.pgd
and init_mm.pgd is initialized at boot (instead of compile time)
to the physmem virtual mapping of init_level4_pgd. The
physical address changed.
Except for the for EMPTY_ZERO page all of the remaining references
to __pa_symbol appear to be during kernel initialization. So this
should reduce the cost of __pa in the common case, even on a relocated
kernel.
As this is technically a semantic change we need to be on the lookout
for anything I missed. But it works for me (tm).
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name. Which is
pain for caching and the proc interface never implemented.
I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.
So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Basically everything was done but I removed all element initializers from the
trailing entries to make it clear the entire last entry should be zero filled.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn,
prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus
generating compiler warnings of unused symbols, hence forcing people to add
#ifdefs.
the compiler can skip truly unused functions just fine:
text data bss dec hex filename
1624412 728710 3674856 6027978 5bfaca vmlinux.before
1624412 728710 3674856 6027978 5bfaca vmlinux.after
[akpm@osdl.org: topology.c fix]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The last thing we agreed on was to remove the macros entirely for 2.6.19,
on all architectures. Unfortunately, I think nobody actually _did_ that,
so they are still there.
[akpm@osdl.org: x86_64 fix]
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Schafer <gschafer@zip.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The final line of /proc/<pid>/maps on x86_64 for native 64-bit
tasks shows an incorrect ending address and incorrect permissions. There
is only a single page mapped in this vsyscall region, and it is accessible
for both read and execute.
The patch below fixes this. (Since 32-bit-compat tasks have a real vma
with correct perms/range, no change is necessary for that scenario.)
Before the patch, a "cat /proc/self/maps | tail -1" shows this:
ffffffffff600000-ffffffffffe00000 ---p 00000000 [...]
After the patch, this is the output:
ffffffffff600000-ffffffffff601000 r-xp 00000000 [...]
Signed-off-by: Ernie Petrides <petrides@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
The vgetcpu per CPU initialization previously relied on CPU hotplug
events for all CPUs to initialize the per CPU state. That only
worked only on kernels with CONFIG_HOTPLUG_CPU enabled. On the
others some CPUs didn't get their state initialized properly
and vgetcpu wouldn't work.
Change the initialization sequence to instead run in a normal
initcall (which runs after the normal CPU bootup) and initialize
all running CPUs there. Later hotplug CPUs are still handled
with an hotplug notifier.
This actually simplifies the code somewhat.
Signed-off-by: Andi Kleen <ak@suse.de>
With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies.
So we can kill wall_jiffies completely.
This is just a cleanup and logically should not change any real behavior
except for one thing: RTC updating code in (old) ppc and xtensa use a
condition "jiffies - wall_jiffies == 1". This condition is never met so I
suppose it is just a bug. I just remove that condition only instead of
kill the whole "if" block.
[heiko.carstens@de.ibm.com: s390 build fix and cleanup]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP
capability uses either the RDTSCP or CPUID to obtain a CPU and node
numbers and pass them to the program.
AK: Lots of changes over Vojtech's original code:
Better prototype for vgetcpu()
It's better to pass the cpu / node numbers as separate arguments
to avoid mistakes when going from SMP to NUMA.
Also add a fast time stamp based cache using a user supplied
argument to speed things more up.
Use fast method from Chuck Ebbert to retrieve node/cpu from
GDT limit instead of CPUID
Made sure RDTSCP init is always executed after node is known.
Drop printk
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Andi Kleen <ak@suse.de>
Originally from Matt Tolentino
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are unfortunately more and more multi processor Opteron systems which
don't have HPET timer support in the southbridge. This covers in particular
Nvidia and VIA chipsets. They also don't guarantee that the TSCs are
synchronized between CPUs; and especially with MP powernow the systems are
nearly unusable because the time gets very inconsistent between CPUs.
The timer code for x86-64 was originally written under the assumption that we
could fall back to the HPET timer on such systems. But this doesn't work
there.
Another alternative is to use the ACPI PM timer as primary time source. This
patch does that. The kernel only uses PM timer when there is no other choice
because it has some disadvantages.
Ported over from i386. It should be faster than the i386 version because I
dropped the "read three times" workaround, but is still considerable slower
than HPET and also does not work together with vsyscalls which have to be
disabled.
Cc: <mark.langsdorf@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
