linux-toradex.git/include/linux/kprobes.h, branch v3.14-rc2

kprobes: allow to specify custom allocator for insn caches

2013-09-11T22:58:52+00:00

The current two insn slot caches both use module_alloc/module_free to
allocate and free insn slot cache pages.

For s390 this is not sufficient since there is the need to allocate insn
slots that are either within the vmalloc module area or within dma memory.

Therefore add a mechanism which allows to specify an own allocator for an
own insn slot cache.

Signed-off-by: Heiko Carstens 
Acked-by: Masami Hiramatsu 
Cc: Ananth N Mavinakayanahalli 
Cc: Ingo Molnar 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: unify insn caches

2013-09-11T22:58:52+00:00

The current kpropes insn caches allocate memory areas for insn slots
with module_alloc().  The assumption is that the kernel image and module
area are both within the same +/- 2GB memory area.

This however is not true for s390 where the kernel image resides within
the first 2GB (DMA memory area), but the module area is far away in the
vmalloc area, usually somewhere close below the 4TB area.

For new pc relative instructions s390 needs insn slots that are within
+/- 2GB of each area.  That way we can patch displacements of
pc-relative instructions within the insn slots just like x86 and
powerpc.

The module area works already with the normal insn slot allocator,
however there is currently no way to get insn slots that are within the
first 2GB on s390 (aka DMA area).

Therefore this patch set modifies the kprobes insn slot cache code in
order to allow to specify a custom allocator for the insn slot cache
pages.  In addition architecure can now have private insn slot caches
withhout the need to modify common code.

Patch 1 unifies and simplifies the current insn and optinsn caches
        implementation. This is a preparation which allows to add more
        insn caches in a simple way.

Patch 2 adds the possibility to specify a custom allocator.

Patch 3 makes s390 use the new insn slot mechanisms and adds support for
        pc-relative instructions with long displacements.

This patch (of 3):

The two insn caches (insn, and optinsn) each have an own mutex and
alloc/free functions (get_[opt]insn_slot() / free_[opt]insn_slot()).

Since there is the need for yet another insn cache which satifies dma
allocations on s390, unify and simplify the current implementation:

- Move the per insn cache mutex into struct kprobe_insn_cache.
- Move the alloc/free functions to kprobe.h so they are simply
  wrappers for the generic __get_insn_slot/__free_insn_slot functions.
  The implementation is done with a DEFINE_INSN_CACHE_OPS() macro
  which provides the alloc/free functions for each cache if needed.
- move the struct kprobe_insn_cache to kprobe.h which allows to generate
  architecture specific insn slot caches outside of the core kprobes
  code.

Signed-off-by: Heiko Carstens 
Cc: Masami Hiramatsu 
Cc: Ananth N Mavinakayanahalli 
Cc: Ingo Molnar 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: Move __kprobes definition into compiler.h

2013-04-08T15:28:34+00:00

Currently, __kprobes is defined in linux/kprobes.h which
is too big to be included in small or basic headers
that want to make use of this simple attribute.

So move __kprobes definition into linux/compiler.h
in which other compiler attributes are defined.

Signed-off-by: Masami Hiramatsu 
Cc: Timo Juhani Lindfors 
Cc: Ananth N Mavinakayanahalli 
Cc: Pavel Emelyanov 
Cc: Jiri Kosina 
Cc: Nadia Yvette Chambers 
Cc: yrl.pp-manager.tt@hitachi.com
Cc: David S. Miller 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20130404104049.21071.20908.stgit@mhiramat-M0-7522
[ Improved the attribute explanation a bit. ]
Signed-off-by: Ingo Molnar

kprobes/x86: Move ftrace-based kprobe code into kprobes-ftrace.c

2013-01-21T18:22:36+00:00

Split ftrace-based kprobes code from kprobes, and introduce
CONFIG_(HAVE_)KPROBES_ON_FTRACE Kconfig flags.
For the cleanup reason, this also moves kprobe_ftrace check
into skip_singlestep.

Link: http://lkml.kernel.org/r/20120928081520.3560.25624.stgit@ltc138.sdl.hitachi.co.jp

Cc: Ingo Molnar 
Cc: Ananth N Mavinakayanahalli 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Frederic Weisbecker 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

kprobes/x86: ftrace based optimization for x86

2012-07-31T14:29:59+00:00

Add function tracer based kprobe optimization support
handlers on x86. This allows kprobes to use function
tracer for probing on mcount call.

Link: http://lkml.kernel.org/r/20120605102838.27845.26317.stgit@localhost.localdomain

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Ananth N Mavinakayanahalli 
Cc: "Frank Ch. Eigler" 
Cc: Andrew Morton 
Cc: Frederic Weisbecker 
Signed-off-by: Masami Hiramatsu 

[ Updated to new port of ftrace save regs functions ]

Signed-off-by: Steven Rostedt

kprobes: introduce ftrace based optimization

2012-07-31T14:29:58+00:00

Introduce function trace based kprobes optimization.

With using ftrace optimization, kprobes on the mcount calling
address, use ftrace's mcount call instead of breakpoint.
Furthermore, this optimization works with preemptive kernel
not like as current jump-based optimization. Of cource,
this feature works only if the probe is on mcount call.

Only if kprobe.break_handler is set, that probe is not
optimized with ftrace (nor put on ftrace). The reason why this
limitation comes is that this break_handler may be used only
from jprobes which changes ip address (for fetching the function
arguments), but function tracer ignores modified ip address.

Changes in v2:
 - Fix ftrace_ops registering right after setting its filter.
 - Unregister ftrace_ops if there is no kprobe using.
 - Remove notrace dependency from __kprobes macro.

Link: http://lkml.kernel.org/r/20120605102832.27845.63461.stgit@localhost.localdomain

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Ananth N Mavinakayanahalli 
Cc: "Frank Ch. Eigler" 
Cc: Andrew Morton 
Cc: Frederic Weisbecker 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

BUG: headers with BUG/BUG_ON etc. need linux/bug.h

2012-03-04T22:54:34+00:00

If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
other BUG variant in a static inline (i.e. not in a #define) then
that header really should be including  and not just
expecting it to be implicitly present.

We can make this change risk-free, since if the files using these
headers didn't have exposure to linux/bug.h already, they would have
been causing compile failures/warnings.

Signed-off-by: Paul Gortmaker

locking, kprobes: Annotate the hash locks and kretprobe.lock as raw

2011-09-13T09:11:45+00:00

The kprobe locks can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar

Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2011-01-08T01:02:58+00:00

* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits)
  gameport: use this_cpu_read instead of lookup
  x86: udelay: Use this_cpu_read to avoid address calculation
  x86: Use this_cpu_inc_return for nmi counter
  x86: Replace uses of current_cpu_data with this_cpu ops
  x86: Use this_cpu_ops to optimize code
  vmstat: User per cpu atomics to avoid interrupt disable / enable
  irq_work: Use per cpu atomics instead of regular atomics
  cpuops: Use cmpxchg for xchg to avoid lock semantics
  x86: this_cpu_cmpxchg and this_cpu_xchg operations
  percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support
  percpu,x86: relocate this_cpu_add_return() and friends
  connector: Use this_cpu operations
  xen: Use this_cpu_inc_return
  taskstats: Use this_cpu_ops
  random: Use this_cpu_inc_return
  fs: Use this_cpu_inc_return in buffer.c
  highmem: Use this_cpu_xx_return() operations
  vmstat: Use this_cpu_inc_return for vm statistics
  x86: Support for this_cpu_add, sub, dec, inc_return
  percpu: Generic support for this_cpu_add, sub, dec, inc_return
  ...

Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c}
as per Tejun.

kprobes: Use this_cpu_ops

2010-12-17T14:07:19+00:00

Use this_cpu ops in various places to optimize per cpu data access.

Cc: Jason Baron 
Cc: Namhyung Kim 
Acked-by: H. Peter Anvin 
Signed-off-by: Christoph Lameter 
Signed-off-by: Tejun Heo