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  1. 28 4月, 2011 1 次提交
  3. 10 12月, 2009 1 次提交
  5. 02 10月, 2009 1 次提交
    • A
      core, x86: Add user return notifiers · 7c68af6e
      由 Avi Kivity 提交于 
      Add a general per-cpu notifier that is called whenever the kernel is
about to return to userspace.  The notifier uses a thread_info flag
and existing checks, so there is no impact on user return or context
switch fast paths.

This will be used initially to speed up KVM task switching by lazily
updating MSRs.
Signed-off-by: NAvi Kivity <avi@redhat.com>
LKML-Reference: <1253342422-13811-1-git-send-email-avi@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      7c68af6e
  7. 02 9月, 2009 1 次提交
    • D
      KEYS: Add a keyctl to install a process's session keyring on its parent [try #6] · ee18d64c
      由 David Howells 提交于 
      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: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>
      ee18d64c
  9. 10 7月, 2009 1 次提交
  11. 04 6月, 2009 2 次提交
    • A
      x86, mce: support action-optional machine checks · 9b1beaf2
      由 Andi Kleen 提交于 
      Newer Intel CPUs support a new class of machine checks called recoverable
action optional.

Action Optional means that the CPU detected some form of corruption in
the background and tells the OS about using a machine check
exception. The OS can then take appropiate action, like killing the
process with the corrupted data or logging the event properly to disk.

This is done by the new generic high level memory failure handler added
in a earlier patch. The high level handler takes the address with the
failed memory and does the appropiate action, like killing the process.

In this version of the patch the high level handler is stubbed out
with a weak function to not create a direct dependency on the hwpoison
branch.

The high level handler cannot be directly called from the machine check
exception though, because it has to run in a defined process context to
be able to sleep when taking VM locks (it is not expected to sleep for a
long time, just do so in some exceptional cases like lock contention)

Thus the MCE handler has to queue a work item for process context,
trigger process context and then call the high level handler from there.

This patch adds two path to process context: through a per thread kernel
exit notify_user() callback or through a high priority work item.
The first runs when the process exits back to user space, the other when
it goes to sleep and there is no higher priority process.

The machine check handler will schedule both, and whoever runs first
will grab the event. This is done because quick reaction to this
event is critical to avoid a potential more fatal machine check
when the corruption is consumed.

There is a simple lock less ring buffer to queue the corrupted
addresses between the exception handler and the process context handler.
Then in process context it just calls the high level VM code with
the corrupted PFNs.

The code adds the required code to extract the failed address from
the CPU's machine check registers. It doesn't try to handle all
possible cases -- the specification has 6 different ways to specify
memory address -- but only the linear address.

Most of the required checking has been already done earlier in the
mce_severity rule checking engine.  Following the Intel
recommendations Action Optional errors are only enabled for known
situations (encoded in MCACODs). The errors are ignored otherwise,
because they are action optional.

v2: Improve comment, disable preemption while processing ring buffer
    (reported by Ying Huang)
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      9b1beaf2
    • A
      x86, mce: rename mce_notify_user to mce_notify_irq · 9ff36ee9
      由 Andi Kleen 提交于 
      Rename the mce_notify_user function to mce_notify_irq. The next
patch will split the wakeup handling of interrupt context
and of process context and it's better to give it a clearer
name for this.

Contains a fix from Ying Huang

[ Impact: cleanup ]
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      9ff36ee9
  13. 03 6月, 2009 1 次提交
  15. 29 5月, 2009 1 次提交
    • A
      x86, mce: use 64bit machine check code on 32bit · 4efc0670
      由 Andi Kleen 提交于 
      The 64bit machine check code is in many ways much better than
the 32bit machine check code: it is more specification compliant,
is cleaner, only has a single code base versus one per CPU,
has better infrastructure for recovery, has a cleaner way to communicate
with user space etc. etc.

Use the 64bit code for 32bit too.

This is the second attempt to do this. There was one a couple of years
ago to unify this code for 32bit and 64bit.  Back then this ran into some
trouble with K7s and was reverted.

I believe this time the K7 problems (and some others) are addressed.
I went over the old handlers and was very careful to retain
all quirks.

But of course this needs a lot of testing on old systems. On newer
64bit capable systems I don't expect much problems because they have been
already tested with the 64bit kernel.

I made this a CONFIG for now that still allows to select the old
machine check code. This is mostly to make testing easier,
if someone runs into a problem we can ask them to try
with the CONFIG switched.

The new code is default y for more coverage.

Once there is confidence the 64bit code works well on older hardware
too the CONFIG_X86_OLD_MCE and the associated code can be easily
removed.

This causes a behaviour change for 32bit installations. They now
have to install the mcelog package to be able to log
corrected machine checks.

The 64bit machine check code only handles CPUs which support the
standard Intel machine check architecture described in the IA32 SDM.
The 32bit code has special support for some older CPUs which
have non standard machine check architectures, in particular
WinChip C3 and Intel P5.  I made those a separate CONFIG option
and kept them for now. The WinChip variant could be probably
removed without too much pain, it doesn't really do anything
interesting. P5 is also disabled by default (like it
was before) because many motherboards have it miswired, but
according to Alan Cox a few embedded setups use that one.

Forward ported/heavily changed version of old patch, original patch
included review/fixes from Thomas Gleixner, Bert Wesarg.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      4efc0670
  17. 06 4月, 2009 1 次提交
    • P
      perf_counter: unify and fix delayed counter wakeup · 925d519a
      由 Peter Zijlstra 提交于 
      While going over the wakeup code I noticed delayed wakeups only work
for hardware counters but basically all software counters rely on
them.

This patch unifies and generalizes the delayed wakeup to fix this
issue.

Since we're dealing with NMI context bits here, use a cmpxchg() based
single link list implementation to track counters that have pending
wakeups.

[ This should really be generic code for delayed wakeups, but since we
  cannot use cmpxchg()/xchg() in generic code, I've let it live in the
  perf_counter code. -- Eric Dumazet could use it to aggregate the
  network wakeups. ]

Furthermore, the x86 method of using TIF flags was flawed in that its
quite possible to end up setting the bit on the idle task, loosing the
wakeup.

The powerpc method uses per-cpu storage and does appear to be
sufficient.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NPaul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171023.153932974@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      925d519a
  19. 01 4月, 2009 1 次提交
  21. 21 3月, 2009 1 次提交
  23. 03 3月, 2009 1 次提交
  25. 28 2月, 2009 5 次提交
  27. 12 2月, 2009 2 次提交
    • H
      x86: merge sys_rt_sigreturn between 32 and 64 bits · 74452509
      由 H. Peter Anvin 提交于 
      Impact: cleanup

With the recent changes in the 32-bit code to make system calls which
use struct pt_regs take a pointer, sys_rt_sigreturn() have become
identical between 32 and 64 bits, and both are empty wrappers around
do_rt_sigreturn().  Remove both wrappers and rename both to
sys_rt_sigreturn().

Cc: Brian Gerst <brgerst@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      74452509
    • B
      x86: use regparm(3) for passed-in pt_regs pointer · b12bdaf1
      由 Brian Gerst 提交于 
      Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to take the pointer as an argument instead of relying on
the assumption that the pt_regs structure overlaps the function
arguments.

Drop the use of regparm(1) due to concern about gcc bugs, and to move
in the direction of the eventual removal of regparm(0) for asmlinkage.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      b12bdaf1
  29. 11 2月, 2009 1 次提交
  31. 10 2月, 2009 1 次提交
    • T
      x86: add %gs accessors for x86_32 · d9a89a26
      由 Tejun Heo 提交于 
      Impact: cleanup

On x86_32, %gs is handled lazily.  It's not saved and restored on
kernel entry/exit but only when necessary which usually is during task
switch but there are few other places.  Currently, it's done by
calling savesegment() and loadsegment() explicitly.  Define
get_user_gs(), set_user_gs() and task_user_gs() and use them instead.

While at it, clean up register access macros in signal.c.

This cleans up code a bit and will help future changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      d9a89a26
  33. 24 1月, 2009 1 次提交
  35. 21 1月, 2009 1 次提交
  37. 18 12月, 2008 2 次提交
  39. 17 12月, 2008 1 次提交
  41. 08 12月, 2008 2 次提交
  43. 26 11月, 2008 4 次提交
  45. 23 11月, 2008 3 次提交
  47. 21 11月, 2008 1 次提交
  49. 12 11月, 2008 1 次提交
  51. 08 11月, 2008 1 次提交
  53. 06 11月, 2008 1 次提交