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  1. 07 3月, 2014 3 次提交
  3. 30 1月, 2014 1 次提交
  5. 14 11月, 2013 1 次提交
  7. 25 9月, 2013 1 次提交
  9. 04 7月, 2013 1 次提交
  11. 08 4月, 2013 1 次提交
  13. 13 2月, 2013 1 次提交
    • S
      tracing/syscalls: Allow archs to ignore tracing compat syscalls · f431b634
      由 Steven Rostedt 提交于 
      The tracing of ia32 compat system calls has been a bit of a pain as they
use different system call numbers than the 64bit equivalents.

I wrote a simple 'lls' program that lists files. I compiled it as a i686
ELF binary and ran it under a x86_64 box. This is the result:

echo 0 > /debug/tracing/tracing_on
echo 1 > /debug/tracing/events/syscalls/enable
echo 1 > /debug/tracing/tracing_on ; ./lls ; echo 0 > /debug/tracing/tracing_on

grep lls /debug/tracing/trace

[.. skipping calls before TS_COMPAT is set ...]

             lls-1127  [005] d...   936.409188: sys_recvfrom(fd: 0, ubuf: 4d560fc4, size: 0, flags: 8048034, addr: 8, addr_len: f7700420)
             lls-1127  [005] d...   936.409190: sys_recvfrom -> 0x8a77000
             lls-1127  [005] d...   936.409211: sys_lgetxattr(pathname: 0, name: 1000, value: 3, size: 22)
             lls-1127  [005] d...   936.409215: sys_lgetxattr -> 0xf76ff000
             lls-1127  [005] d...   936.409223: sys_dup2(oldfd: 4d55ae9b, newfd: 4)
             lls-1127  [005] d...   936.409228: sys_dup2 -> 0xfffffffffffffffe
             lls-1127  [005] d...   936.409236: sys_newfstat(fd: 4d55b085, statbuf: 80000)
             lls-1127  [005] d...   936.409242: sys_newfstat -> 0x3
             lls-1127  [005] d...   936.409243: sys_removexattr(pathname: 3, name: ffcd0060)
             lls-1127  [005] d...   936.409244: sys_removexattr -> 0x0
             lls-1127  [005] d...   936.409245: sys_lgetxattr(pathname: 0, name: 19614, value: 1, size: 2)
             lls-1127  [005] d...   936.409248: sys_lgetxattr -> 0xf76e5000
             lls-1127  [005] d...   936.409248: sys_newlstat(filename: 3, statbuf: 19614)
             lls-1127  [005] d...   936.409249: sys_newlstat -> 0x0
             lls-1127  [005] d...   936.409262: sys_newfstat(fd: f76fb588, statbuf: 80000)
             lls-1127  [005] d...   936.409279: sys_newfstat -> 0x3
             lls-1127  [005] d...   936.409279: sys_close(fd: 3)
             lls-1127  [005] d...   936.421550: sys_close -> 0x200
             lls-1127  [005] d...   936.421558: sys_removexattr(pathname: 3, name: ffcd00d0)
             lls-1127  [005] d...   936.421560: sys_removexattr -> 0x0
             lls-1127  [005] d...   936.421569: sys_lgetxattr(pathname: 4d564000, name: 1b1abc, value: 5, size: 802)
             lls-1127  [005] d...   936.421574: sys_lgetxattr -> 0x4d564000
             lls-1127  [005] d...   936.421575: sys_capget(header: 4d70f000, dataptr: 1000)
             lls-1127  [005] d...   936.421580: sys_capget -> 0x0
             lls-1127  [005] d...   936.421580: sys_lgetxattr(pathname: 4d710000, name: 3000, value: 3, size: 812)
             lls-1127  [005] d...   936.421589: sys_lgetxattr -> 0x4d710000
             lls-1127  [005] d...   936.426130: sys_lgetxattr(pathname: 4d713000, name: 2abc, value: 3, size: 32)
             lls-1127  [005] d...   936.426141: sys_lgetxattr -> 0x4d713000
             lls-1127  [005] d...   936.426145: sys_newlstat(filename: 3, statbuf: f76ff3f0)
             lls-1127  [005] d...   936.426146: sys_newlstat -> 0x0
             lls-1127  [005] d...   936.431748: sys_lgetxattr(pathname: 0, name: 1000, value: 3, size: 22)

Obviously I'm not calling newfstat with a fd of 4d55b085. The calls are
obviously incorrect, and confusing.

Other efforts have been made to fix this:

https://lkml.org/lkml/2012/3/26/367

But the real solution is to rewrite the syscall internals and come up
with a fixed solution. One that doesn't require all the kluge that the
current solution has.

Thus for now, instead of outputting incorrect data, simply ignore them.
With this patch the changes now have:

 #> grep lls /debug/tracing/trace
 #>

Compat system calls simply are not traced. If users need compat
syscalls, then they should just use the raw syscall tracepoints.

For an architecture to make their compat syscalls ignored, it must
define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS (done in asm/ftrace.h) and also
define an arch_trace_is_compat_syscall() function that will return true
if the current task should ignore tracing the syscall.

I want to stress that this change does not affect actual syscalls in any
way, shape or form. It is only used within the tracing system and
doesn't interfere with the syscall logic at all. The changes are
consolidated nicely into trace_syscalls.c and asm/ftrace.h.

I had to make one small modification to asm/thread_info.h and that was
to remove the include of asm/ftrace.h. As asm/ftrace.h required the
current_thread_info() it was causing include hell. That include was
added back in 2008 when the function graph tracer was added:

 commit caf4b323 "tracing, x86: add low level support for ftrace return tracing"

It does not need to be included there.

Link: http://lkml.kernel.org/r/1360703939.21867.99.camel@gandalf.local.homeAcked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      f431b634
  15. 26 9月, 2012 1 次提交
    • F
      x86: Syscall hooks for userspace RCU extended QS · bf5a3c13
      由 Frederic Weisbecker 提交于 
      Add syscall slow path hooks to notify syscall entry
and exit on CPUs that want to support userspace RCU
extended quiescent state.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      bf5a3c13
  17. 20 9月, 2012 1 次提交
    • A
      x86: get rid of TIF_IRET hackery · e76623d6
      由 Al Viro 提交于 
      TIF_NOTIFY_RESUME will work in precisely the same way; all that
is achieved by TIF_IRET is appearing that there's some work to be
done, so we end up on the iret exit path.  Just use NOTIFY_RESUME.
And for execve() do that in 32bit start_thread(), not sys_execve()
itself.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      e76623d6
  19. 02 6月, 2012 2 次提交
  21. 15 5月, 2012 1 次提交
  23. 08 5月, 2012 2 次提交
  25. 14 3月, 2012 1 次提交
    • S
      uprobes/core: Handle breakpoint and singlestep exceptions · 0326f5a9
      由 Srikar Dronamraju 提交于 
      Uprobes uses exception notifiers to get to know if a thread hit
a breakpoint or a singlestep exception.

When a thread hits a uprobe or is singlestepping post a uprobe
hit, the uprobe exception notifier sets its TIF_UPROBE bit,
which will then be checked on its return to userspace path
(do_notify_resume() ->uprobe_notify_resume()), where the
consumers handlers are run (in task context) based on the
defined filters.

Uprobe hits are thread specific and hence we need to maintain
information about if a task hit a uprobe, what uprobe was hit,
the slot where the original instruction was copied for xol so
that it can be singlestepped with appropriate fixups.

In some cases, special care is needed for instructions that are
executed out of line (xol). These are architecture specific
artefacts, such as handling RIP relative instructions on x86_64.

Since the instruction at which the uprobe was inserted is
executed out of line, architecture specific fixups are added so
that the thread continues normal execution in the presence of a
uprobe.

Postpone the signals until we execute the probed insn.
post_xol() path does a recalc_sigpending() before return to
user-mode, this ensures the signal can't be lost.

Uprobes relies on DIE_DEBUG notification to notify if a
singlestep is complete.

Adds x86 specific uprobe exception notifiers and appropriate
hooks needed to determine a uprobe hit and subsequent post
processing.

Add requisite x86 fixups for xol for uprobes. Specific cases
needing fixups include relative jumps (x86_64), calls, etc.

Where possible, we check and skip singlestepping the
breakpointed instructions. For now we skip single byte as well
as few multibyte nop instructions. However this can be extended
to other instructions too.

Credits to Oleg Nesterov for suggestions/patches related to
signal, breakpoint, singlestep handling code.
Signed-off-by: NSrikar 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/20120313180011.29771.89027.sendpatchset@srdronam.in.ibm.com
[ Performed various cleanliness edits ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0326f5a9
  27. 13 3月, 2012 1 次提交
  29. 21 2月, 2012 2 次提交
  31. 19 2月, 2012 1 次提交
    • L
      i387: move TS_USEDFPU flag from thread_info to task_struct · f94edacf
      由 Linus Torvalds 提交于 
      This moves the bit that indicates whether a thread has ownership of the
FPU from the TS_USEDFPU bit in thread_info->status to a word of its own
(called 'has_fpu') in task_struct->thread.has_fpu.

This fixes two independent bugs at the same time:

 - changing 'thread_info->status' from the scheduler causes nasty
   problems for the other users of that variable, since it is defined to
   be thread-synchronous (that's what the "TS_" part of the naming was
   supposed to indicate).

   So perfectly valid code could (and did) do

	ti->status |= TS_RESTORE_SIGMASK;

   and the compiler was free to do that as separate load, or and store
   instructions.  Which can cause problems with preemption, since a task
   switch could happen in between, and change the TS_USEDFPU bit. The
   change to TS_USEDFPU would be overwritten by the final store.

   In practice, this seldom happened, though, because the 'status' field
   was seldom used more than once, so gcc would generally tend to
   generate code that used a read-modify-write instruction and thus
   happened to avoid this problem - RMW instructions are naturally low
   fat and preemption-safe.

 - On x86-32, the current_thread_info() pointer would, during interrupts
   and softirqs, point to a *copy* of the real thread_info, because
   x86-32 uses %esp to calculate the thread_info address, and thus the
   separate irq (and softirq) stacks would cause these kinds of odd
   thread_info copy aliases.

   This is normally not a problem, since interrupts aren't supposed to
   look at thread information anyway (what thread is running at
   interrupt time really isn't very well-defined), but it confused the
   heck out of irq_fpu_usable() and the code that tried to squirrel
   away the FPU state.

   (It also caused untold confusion for us poor kernel developers).

It also turns out that using 'task_struct' is actually much more natural
for most of the call sites that care about the FPU state, since they
tend to work with the task struct for other reasons anyway (ie
scheduling).  And the FPU data that we are going to save/restore is
found there too.

Thanks to Arjan Van De Ven <arjan@linux.intel.com> for pointing us to
the %esp issue.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Reported-and-tested-by: NRaphael Prevost <raphael@buro.asia>
Acked-and-tested-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Tested-by: NPeter Anvin <hpa@zytor.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f94edacf
  33. 16 1月, 2012 1 次提交
  35. 13 1月, 2012 1 次提交
  37. 06 12月, 2011 1 次提交
    • J
      x86-64: Slightly shorten line system call entry and exit paths · 46db09d3
      由 Jan Beulich 提交于 
      GET_THREAD_INFO() involves a memory read immediately followed by
an "sub" on the value read, in turn (in several cases)
immediately followed by a use of the calculated value as the
base address of a memory access. This combination of
instructions has a non-negligible potential for stalls.

In the system call entry point code, however, the (fixed) offset
of the stack pointer from the end of the stack is generally
known, and hence we can instead avoid the memory load and
subtract, and instead do the memory reference using %rsp as the
base register. To do so in a legible fashion, introduce a
THREAD_INFO() macro which, provided a register (generally %rsp)
and the known offset from the end of the stack, produces a
suitable memory access operand.

The patch attempts to only touch the fast paths (no auditing and
alike), but manages to do so only in the 64-bit entry point
case; the compatibility mode entry points have so many
interdependencies between their various branch targets that it
was necessary to also adjust the slow paths to eliminate the
risk of having missed some register dependency during code
analysis.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/4ED4CD690200007800064075@nat28.tlf.novell.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      46db09d3
  39. 05 12月, 2011 1 次提交
  41. 22 11月, 2011 1 次提交
  43. 27 7月, 2011 1 次提交
  45. 23 3月, 2011 1 次提交
  47. 28 5月, 2010 1 次提交
  49. 14 5月, 2010 1 次提交
  51. 11 5月, 2010 1 次提交
    • A
      x86: Eliminate TS_XSAVE · c9ad4882
      由 Avi Kivity 提交于 
      The fpu code currently uses current->thread_info->status & TS_XSAVE as
a way to distinguish between XSAVE capable processors and older processors.
The decision is not really task specific; instead we use the task status to
avoid a global memory reference - the value should be the same across all
threads.

Eliminate this tie-in into the task structure by using an alternative
instruction keyed off the XSAVE cpu feature; this results in shorter and
faster code, without introducing a global memory reference.

[ hpa: in the future, this probably should use an asm jmp ]
Signed-off-by: NAvi Kivity <avi@redhat.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1273135546-29690-2-git-send-email-avi@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      c9ad4882
  53. 26 3月, 2010 2 次提交
    • P
      x86, ptrace: Fix block-step · ea8e61b7
      由 Peter Zijlstra 提交于 
      Implement ptrace-block-step using TIF_BLOCKSTEP which will set
DEBUGCTLMSR_BTF when set for a task while preserving any other
DEBUGCTLMSR bits.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100325135414.017536066@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      ea8e61b7
    • P
      x86, perf, bts, mm: Delete the never used BTS-ptrace code · faa4602e
      由 Peter Zijlstra 提交于 
      Support for the PMU's BTS features has been upstreamed in
v2.6.32, but we still have the old and disabled ptrace-BTS,
as Linus noticed it not so long ago.

It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without
regard for other uses (perf) and doesn't provide the flexibility
needed for perf either.

Its users are ptrace-block-step and ptrace-bts, since ptrace-bts
was never used and ptrace-block-step can be implemented using a
much simpler approach.

So axe all 3000 lines of it. That includes the *locked_memory*()
APIs in mm/mlock.c as well.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100325135413.938004390@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      faa4602e
  55. 30 1月, 2010 1 次提交
  57. 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
  59. 26 8月, 2009 1 次提交
    • J
      tracing: Rename FTRACE_SYSCALLS for tracepoints · 66700001
      由 Josh Stone 提交于 
      s/HAVE_FTRACE_SYSCALLS/HAVE_SYSCALL_TRACEPOINTS/g
s/TIF_SYSCALL_FTRACE/TIF_SYSCALL_TRACEPOINT/g

The syscall enter/exit tracing is no longer specific to just ftrace, so
they now have names that reflect their tie to tracepoints instead.
Signed-off-by: NJosh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-2-git-send-email-jistone@redhat.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      66700001
  61. 04 8月, 2009 1 次提交
  63. 11 7月, 2009 1 次提交
  65. 15 6月, 2009 1 次提交
  67. 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