Commit Graph

55 Commits

Author SHA1 Message Date
KUMANO Syuhei
737480a0d5 kprobes/x86: Fix the return address of multiple kretprobes
Fix the return address of subsequent kretprobes when multiple
kretprobes are set on the same function.

For example:

 # cd /sys/kernel/debug/tracing
 # echo "r:event1 sys_symlink" > kprobe_events
 # echo "r:event2 sys_symlink" >> kprobe_events
 # echo 1 > events/kprobes/enable
 # ln -s /tmp/foo /tmp/bar

(without this patch)

 # cat trace
              ln-897   [000] 20404.133727: event1: (kretprobe_trampoline+0x0/0x4c <- sys_symlink)
              ln-897   [000] 20404.133747: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink)

(with this patch)

 # cat trace
              ln-740   [000] 13799.491076: event1: (system_call_fastpath+0x16/0x1b <- sys_symlink)
              ln-740   [000] 13799.491096: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink)

Signed-off-by: KUMANO Syuhei <kumano.prog@gmail.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
LKML-Reference: <1281853084.3254.11.camel@camp10-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-19 12:49:56 +02:00
Ingo Molnar
9dcdbf7a33 Merge branch 'linus' into perf/core
Merge reason: Pick up the latest perf fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-07-21 21:43:06 +02:00
Roland McGrath
a197479848 x86: kprobes: fix swapped segment registers in kretprobe
In commit f007ea26, the order of the %es and %ds segment registers
got accidentally swapped, so synthesized 'struct pt_regs' frames
have the two values inverted.  It's almost sure that these values
never matter, and that they also never differ.  But wrong is wrong.

Signed-off-by: Roland McGrath <roland@redhat.com>
2010-07-18 15:05:34 -07:00
Masami Hiramatsu
567a9fd867 kprobes/x86: Fix kprobes to skip prefixes correctly
Fix resume_execution() and is_IF_modifier() to skip x86
instruction prefixes correctly by using x86 instruction
attribute.

Without this fix, resume_execution() can't handle instructions
which have non-REX prefixes (REX prefixes are skipped). This
will cause unexpected kernel panic by hitting bad address when a
kprobe hits on two-byte ret (e.g. "repz ret" generated for
Athlon/K8 optimization), because it just checks "repz" and can't
recognize the "ret" instruction.

These prefixes can be found easily with x86 instruction
attribute. This patch introduces skip_prefixes() and uses it in
resume_execution() and is_IF_modifier() to skip prefixes.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <4C298A6E.8070609@hitachi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-29 10:43:41 +02:00
Linus Torvalds
4d7b4ac22f Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (311 commits)
  perf tools: Add mode to build without newt support
  perf symbols: symbol inconsistency message should be done only at verbose=1
  perf tui: Add explicit -lslang option
  perf options: Type check all the remaining OPT_ variants
  perf options: Type check OPT_BOOLEAN and fix the offenders
  perf options: Check v type in OPT_U?INTEGER
  perf options: Introduce OPT_UINTEGER
  perf tui: Add workaround for slang < 2.1.4
  perf record: Fix bug mismatch with -c option definition
  perf options: Introduce OPT_U64
  perf tui: Add help window to show key associations
  perf tui: Make <- exit menus too
  perf newt: Add single key shortcuts for zoom into DSO and threads
  perf newt: Exit browser unconditionally when CTRL+C, q or Q is pressed
  perf newt: Fix the 'A'/'a' shortcut for annotate
  perf newt: Make <- exit the ui_browser
  x86, perf: P4 PMU - fix counters management logic
  perf newt: Make <- zoom out filters
  perf report: Report number of events, not samples
  perf hist: Clarify events_stats fields usage
  ...

Fix up trivial conflicts in kernel/fork.c and tools/perf/builtin-record.c
2010-05-18 08:19:03 -07:00
Masami Hiramatsu
829e924585 kprobes/x86: Fix removed int3 checking order
Fix kprobe/x86 to check removed int3 when failing to get kprobe
from hlist. Since we have a time window between checking int3
exists on probed address and getting kprobe on that address,
we can have following scenario:

 -------
 CPU1                     CPU2
 hit int3
 check int3 exists
                          remove int3
                          remove kprobe from hlist
 get kprobe from hlist
 no kprobe->OOPS!
 -------

This patch moves int3 checking if there is no kprobe on that
address for fixing this problem as follows:

 ------
 CPU1                     CPU2
 hit int3
                          remove int3
                          remove kprobe from hlist
 get kprobe from hlist
 no kprobe->check int3 exists
          ->rollback&retry
 ------

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100427223348.2322.9112.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-11 09:14:25 +02:00
Peter Zijlstra
ea8e61b7bb x86, ptrace: Fix block-step
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: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100325135414.017536066@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-26 11:33:57 +01:00
Peter Zijlstra
faa4602e47 x86, perf, bts, mm: Delete the never used BTS-ptrace code
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: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter 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: Ingo Molnar <mingo@elte.hu>
2010-03-26 11:33:55 +01:00
Masami Hiramatsu
c0f7ac3a9e kprobes/x86: Support kprobes jump optimization on x86
Introduce x86 arch-specific optimization code, which supports
both of x86-32 and x86-64.

This code also supports safety checking, which decodes whole of
a function in which probe is inserted, and checks following
conditions before optimization:
 - The optimized instructions which will be replaced by a jump instruction
   don't straddle the function boundary.
 - There is no indirect jump instruction, because it will jumps into
   the address range which is replaced by jump operand.
 - There is no jump/loop instruction which jumps into the address range
   which is replaced by jump operand.
 - Don't optimize kprobes if it is in functions into which fixup code will
   jumps.

This uses text_poke_multibyte() which doesn't support modifying
code on NMI/MCE handler. However, since kprobes itself doesn't
support NMI/MCE code probing, it's not a problem.

Changes in v9:
 - Use *_text_reserved() for checking the probe can be optimized.
 - Verify jump address range is in 2G range when preparing slot.
 - Backup original code when switching optimized buffer, instead of
   preparing buffer, because there can be int3 of other probes in
   preparing phase.
 - Check kprobe is disabled in arch_check_optimized_kprobe().
 - Strictly check indirect jump opcodes (ff /4, ff /5).

Changes in v6:
 - Split stop_machine-based jump patching code.
 - Update comments and coding style.

Changes in v5:
 - Introduce stop_machine-based jump replacing.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133446.6725.78994.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:26 +01:00
Masami Hiramatsu
f007ea2685 kprobes/x86: Cleanup save/restore registers
Introduce SAVE/RESOTRE_REGS_STRING for cleanup
kretprobe-trampoline asm code. These macros will be used for
emulating interruption.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133430.6725.83342.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:26 +01:00
Masami Hiramatsu
0f94eb634e kprobes/x86: Boost probes when reentering
Integrate prepare_singlestep() into setup_singlestep() to boost
up reenter probes, if possible.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133423.6725.12071.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:25 +01:00
Masami Hiramatsu
d498f76395 kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE
Change RELATIVEJUMP_INSTRUCTION macro to RELATIVEJUMP_OPCODE
since it represents just the opcode byte.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133349.6725.99302.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:24 +01:00
Masami Hiramatsu
4554dbcb85 kprobes: Check probe address is reserved
Check whether the address of new probe is already reserved by
ftrace or alternatives (on x86) when registering new probe.
If reserved, it returns an error and not register the probe.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: przemyslaw@pawelczyk.it
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <20100202214918.4694.94179.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-04 09:36:19 +01:00
Masami Hiramatsu
615d0ebbc7 kprobes: Disable booster when CONFIG_PREEMPT=y
Disable kprobe booster when CONFIG_PREEMPT=y at this time,
because it can't ensure that all kernel threads preempted on
kprobe's boosted slot run out from the slot even using
freeze_processes().

The booster on preemptive kernel will be resumed if
synchronize_tasks() or something like that is introduced.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-04 09:36:18 +01:00
Jiri Kosina
d014d04386 Merge branch 'for-next' into for-linus
Conflicts:

	kernel/irq/chip.c
2009-12-07 18:36:35 +01:00
Linus Torvalds
c2ed69cdc9 Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix a section mismatch in arch/x86/kernel/setup.c
  x86: Fixup last users of irq_chip->typename
  x86: Remove BKL from apm_32
  x86: Remove BKL from microcode
  x86: use kernel_stack_pointer() in kprobes.c
  x86: use kernel_stack_pointer() in kgdb.c
  x86: use kernel_stack_pointer() in dumpstack.c
  x86: use kernel_stack_pointer() in process_32.c
2009-12-05 15:32:18 -08:00
André Goddard Rosa
af901ca181 tree-wide: fix assorted typos all over the place
That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:55 +01:00
Ingo Molnar
96200591a3 Merge branch 'tracing/hw-breakpoints' into perf/core
Conflicts:
	arch/x86/kernel/kprobes.c
	kernel/trace/Makefile

Merge reason: hw-breakpoints perf integration is looking
              good in testing and in reviews, plus conflicts
              are mounting up - so merge & resolve.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21 14:07:23 +01:00
H. Peter Anvin
98272ed0d2 x86: use kernel_stack_pointer() in kprobes.c
The way to obtain a kernel-mode stack pointer from a struct pt_regs in
32-bit mode is "subtle": the stack doesn't actually contain the stack
pointer, but rather the location where it would have been marks the
actual previous stack frame.  For clarity, use kernel_stack_pointer()
instead of coding this weirdness explicitly.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
2009-10-12 14:19:35 -07:00
Masami Hiramatsu
f5ad31158d kprobes/x86-64: Allow to reenter probe on post_handler
Allow to reenter probe on the post_handler of another probe on x86-64,
because x86-64 already allows reentering int3.
In that case, reentered probe just increases kp.nmissed and returns.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090827172304.8246.4822.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-30 03:08:26 +02:00
Masami Hiramatsu
e9afe9e1b3 kprobes/x86: Call BUG() when reentering probe into KPROBES_HIT_SS
Call BUG() when a probe have been hit on the way of kprobe processing
path, because that kind of probes are currently unrecoverable
(recovering it will cause an infinite loop and stack overflow).

The original code seems to assume that it's caused by an int3
which another subsystem inserted on out-of-line singlestep buffer if
the hitting probe is same as current probe. However, in that case,
int3-hitting-address is on the out-of-line buffer and should be
different from first (current) int3 address.
Thus, I decided to remove the code.

I also removes arch_disarm_kprobe() because it will involve other stuffs
in text_poke().

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090827172258.8246.61889.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-30 03:08:26 +02:00
Frederic Weisbecker
24851d2447 tracing/kprobes: Dump the culprit kprobe in case of kprobe recursion
Kprobes can enter into a probing recursion, ie: a kprobe that does an
endless loop because one of its core mechanism function used during
probing is also probed itself.

This patch helps pinpointing the kprobe that raised such recursion
by dumping it and raising a BUG instead of a warning (we also disarm
the kprobe to try avoiding recursion in BUG itself). Having a BUG
instead of a warning stops the stacktrace in the right place and
doesn't pollute the logs with hundreds of traces that eventually end
up in a stack overflow.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
2009-08-27 02:33:03 +02:00
Masami Hiramatsu
89ae465b0e kprobes: Cleanup fix_riprel() using insn decoder on x86
Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using the new x86
instruction decoder instead of using comparisons with raw ad hoc numeric
opcodes.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203436.31965.34374.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-27 00:35:57 +02:00
Masami Hiramatsu
b46b3d70c9 kprobes: Checks probe address is instruction boudary on x86
Ensure safeness of inserting kprobes by checking whether the specified
address is at the first byte of an instruction on x86.
This is done by decoding probed function from its head to the probe
point.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203428.31965.21939.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-27 00:35:56 +02:00
K.Prasad
62edab9056 hw-breakpoints: reset bits in dr6 after the corresponding exception is handled
This patch resets the bit in dr6 after the corresponding exception is
handled in code, so that we keep a clean track of the current virtual debug
status register.

[ Impact: keep track of breakpoints triggering completion ]

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
Ingo Molnar
8302294f43 Merge branch 'tracing/core-v2' into tracing-for-linus
Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c
2009-04-02 00:49:02 +02:00
Masami Hiramatsu
fee039a1d0 x86: kretprobe-booster interrupt emulation code fix
Fix interrupt emulation code in kretprobe-booster according to
pt_regs update (es/ds change and gs adding).

This issue has been reported on systemtap-bugzilla:

  http://sources.redhat.com/bugzilla/show_bug.cgi?id=9965

  | On a -tip kernel on x86_32, kretprobe_example (from samples) triggers the
  | following backtrace when its retprobing a class of functions that cause a
  | copy_from/to_user().
  |
  | BUG: sleeping function called from invalid context at mm/memory.c:3196
  | in_atomic(): 0, irqs_disabled(): 1, pid: 2286, name: cat

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: systemtap-ml <systemtap@sources.redhat.com>
LKML-Reference: <49C7995C.2010601@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-25 18:53:29 +01:00
Jaswinder Singh Rajput
cde5edbda8 x86: kprobes.c fix compilation warning
arch/x86/kernel/kprobes.c:196: warning: passing argument 1 of ‘search_exception_tables’ makes integer from pointer without a cast

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference:<49BED952.2050809@redhat.com>
LKML-Reference: <1237378065.13488.2.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-18 13:21:01 +01:00
Masami Hiramatsu
30390880de prevent boosting kprobes on exception address
Don't boost at the addresses which are listed on exception tables,
because major page fault will occur on those addresses.  In that case,
kprobes can not ensure that when instruction buffer can be freed since
some processes will sleep on the buffer.

kprobes-ia64 already has same check.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-17 09:11:48 -07:00
Masami Hiramatsu
5a4ccaf37f kprobes: check CONFIG_FREEZER instead of CONFIG_PM
Check CONFIG_FREEZER instead of CONFIG_PM because kprobe booster
depends on freeze_processes() and thaw_processes() when CONFIG_PREEMPT=y.

This fixes a linkage error which occurs when CONFIG_PREEMPT=y, CONFIG_PM=y
and CONFIG_FREEZER=n.

Reported-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Len Brown <len.brown@intel.com>
2009-01-16 14:32:17 -05:00
Linus Torvalds
57c44c5f6f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits)
  trivial: chack -> check typo fix in main Makefile
  trivial: Add a space (and a comma) to a printk in 8250 driver
  trivial: Fix misspelling of "firmware" in docs for ncr53c8xx/sym53c8xx
  trivial: Fix misspelling of "firmware" in powerpc Makefile
  trivial: Fix misspelling of "firmware" in usb.c
  trivial: Fix misspelling of "firmware" in qla1280.c
  trivial: Fix misspelling of "firmware" in a100u2w.c
  trivial: Fix misspelling of "firmware" in megaraid.c
  trivial: Fix misspelling of "firmware" in ql4_mbx.c
  trivial: Fix misspelling of "firmware" in acpi_memhotplug.c
  trivial: Fix misspelling of "firmware" in ipw2100.c
  trivial: Fix misspelling of "firmware" in atmel.c
  trivial: Fix misspelled firmware in Kconfig
  trivial: fix an -> a typos in documentation and comments
  trivial: fix then -> than typos in comments and documentation
  trivial: update Jesper Juhl CREDITS entry with new email
  trivial: fix singal -> signal typo
  trivial: Fix incorrect use of "loose" in event.c
  trivial: printk: fix indentation of new_text_line declaration
  trivial: rtc-stk17ta8: fix sparse warning
  ...
2009-01-07 11:31:52 -08:00
Masami Hiramatsu
1294156078 kprobes: add kprobe_insn_mutex and cleanup arch_remove_kprobe()
Add kprobe_insn_mutex for protecting kprobe_insn_pages hlist, and remove
kprobe_mutex from architecture dependent code.

This allows us to call arch_remove_kprobe() (and free_insn_slot) while
holding kprobe_mutex.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:20 -08:00
Frederik Schwarzer
025dfdafe7 trivial: fix then -> than typos in comments and documentation
- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-01-06 11:28:06 +01:00
Srinivasa D S
ef53d9c5e4 kprobes: improve kretprobe scalability with hashed locking
Currently list of kretprobe instances are stored in kretprobe object (as
used_instances,free_instances) and in kretprobe hash table.  We have one
global kretprobe lock to serialise the access to these lists.  This causes
only one kretprobe handler to execute at a time.  Hence affects system
performance, particularly on SMP systems and when return probe is set on
lot of functions (like on all systemcalls).

Solution proposed here gives fine-grain locks that performs better on SMP
system compared to present kretprobe implementation.

Solution:

 1) Instead of having one global lock to protect kretprobe instances
    present in kretprobe object and kretprobe hash table.  We will have
    two locks, one lock for protecting kretprobe hash table and another
    lock for kretporbe object.

 2) We hold lock present in kretprobe object while we modify kretprobe
    instance in kretprobe object and we hold per-hash-list lock while
    modifying kretprobe instances present in that hash list.  To prevent
    deadlock, we never grab a per-hash-list lock while holding a kretprobe
    lock.

 3) We can remove used_instances from struct kretprobe, as we can
    track used instances of kretprobe instances using kretprobe hash
    table.

Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system
with return probes set on all systemcalls looks like this.

cacheline              non-cacheline             Un-patched kernel
aligned patch 	       aligned patch
===============================================================================
real    9m46.784s       9m54.412s                  10m2.450s
user    40m5.715s       40m7.142s                  40m4.273s
sys     2m57.754s       2m58.583s                  3m17.430s
===========================================================

Time duration for kernel compilation ("make -j 8) on the same system, when
kernel is not probed.
=========================
real    9m26.389s
user    40m8.775s
sys     2m7.283s
=========================

Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:30 -07:00
Peter Zijlstra
d54191b85e Kprobe smoke test lockdep warning
On Mon, 2008-04-21 at 18:54 -0400, Masami Hiramatsu wrote:
> Thank you for reporting.
>
> Actually, kprobes tries to fixup thread's flags in post_kprobe_handler
> (which is called from kprobe_exceptions_notify) by
> trace_hardirqs_fixup_flags(pt_regs->flags). However, even the irq flag
> is set in pt_regs->flags, true hardirq is still off until returning
> from do_debug. Thus, lockdep assumes that hardirq is off without annotation.
>
> IMHO, one possible solution is that fixing hardirq flags right after
> notify_die in do_debug instead of in post_kprobe_handler.

My reply to BZ 10489:

> [    2.707509] Kprobe smoke test started
> [    2.709300] ------------[ cut here ]------------
> [    2.709420] WARNING: at kernel/lockdep.c:2658 check_flags+0x4d/0x12c()
> [    2.709541] Modules linked in:
> [    2.709588] Pid: 1, comm: swapper Not tainted 2.6.25.jml.057 #1
> [    2.709588]  [<c0126acc>] warn_on_slowpath+0x41/0x51
> [    2.709588]  [<c010bafc>] ? save_stack_trace+0x1d/0x3b
> [    2.709588]  [<c0140a83>] ? save_trace+0x37/0x89
> [    2.709588]  [<c011987d>] ? kernel_map_pages+0x103/0x11c
> [    2.709588]  [<c0109803>] ? native_sched_clock+0xca/0xea
> [    2.709588]  [<c0142958>] ? mark_held_locks+0x41/0x5c
> [    2.709588]  [<c0382580>] ? kprobe_exceptions_notify+0x322/0x3af
> [    2.709588]  [<c0142aff>] ? trace_hardirqs_on+0xf1/0x119
> [    2.709588]  [<c03825b3>] ? kprobe_exceptions_notify+0x355/0x3af
> [    2.709588]  [<c0140823>] check_flags+0x4d/0x12c
> [    2.709588]  [<c0143c9d>] lock_release+0x58/0x195
> [    2.709588]  [<c038347c>] ? __atomic_notifier_call_chain+0x0/0x80
> [    2.709588]  [<c03834d6>] __atomic_notifier_call_chain+0x5a/0x80
> [    2.709588]  [<c0383508>] atomic_notifier_call_chain+0xc/0xe
> [    2.709588]  [<c013b6d4>] notify_die+0x2d/0x2f
> [    2.709588]  [<c038168a>] do_debug+0x67/0xfe
> [    2.709588]  [<c0381287>] debug_stack_correct+0x27/0x30
> [    2.709588]  [<c01564c0>] ? kprobe_target+0x1/0x34
> [    2.709588]  [<c0156572>] ? init_test_probes+0x50/0x186
> [    2.709588]  [<c04fae48>] init_kprobes+0x85/0x8c
> [    2.709588]  [<c04e947b>] kernel_init+0x13d/0x298
> [    2.709588]  [<c04e933e>] ? kernel_init+0x0/0x298
> [    2.709588]  [<c04e933e>] ? kernel_init+0x0/0x298
> [    2.709588]  [<c0105ef7>] kernel_thread_helper+0x7/0x10
> [    2.709588]  =======================
> [    2.709588] ---[ end trace 778e504de7e3b1e3 ]---
> [    2.709588] possible reason: unannotated irqs-off.
> [    2.709588] irq event stamp: 370065
> [    2.709588] hardirqs last  enabled at (370065): [<c0382580>] kprobe_exceptions_notify+0x322/0x3af
> [    2.709588] hardirqs last disabled at (370064): [<c0381bb7>] do_int3+0x1d/0x7d
> [    2.709588] softirqs last  enabled at (370050): [<c012b464>] __do_softirq+0xfa/0x100
> [    2.709588] softirqs last disabled at (370045): [<c0107438>] do_softirq+0x74/0xd9
> [    2.714751] Kprobe smoke test passed successfully

how I love this stuff...

Ok, do_debug() is a trap, this can happen at any time regardless of the
machine's IRQ state. So the first thing we do is fix up the IRQ state.
Then we call this die notifier stuff; and return with messed up IRQ
state... YAY.

So, kprobes fudges it..

  notify_die(DIE_DEBUG)
    kprobe_exceptions_notify()
      post_kprobe_handler()
        modify regs->flags
        trace_hardirqs_fixup_flags(regs->flags);  <--- must be it

So what's the use of modifying flags if they're not meant to take effect
at some point.

/me tries to reproduce issue; enable kprobes test thingy && boot

OK, that reproduces..

So the below makes it work - but I'm not getting this code; at the time
I wrote that stuff I CC'ed each and every kprobe maintainer listed in
the usual places but got no reposonse - can some please explain this
stuff to me?

Are the saved flags only for the TF bit or are they made in full effect
later (and if so, where) ?

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15 11:18:03 +02:00
gorcunov@gmail.com
a5c15d419d x86: replace most VM86 flags with flags from processor-flags.h
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:41:33 +02:00
Yakov Lerner
acb5b8a2dd x86, kprobes: correct post-eip value in post_hander()
I was trying to get the address of instruction to be executed
next after the kprobed instruction.  But regs->eip in post_handler()
contains value which is useless to the user. It's pre-corrected value.
This value is difficult to use without access to resume_execution(), which
is not exported anyway.
I moved the invocation of post_handler() to *after* resume_execution().
Now regs->eip contains meaningful value in post_handler().

I do not think this change breaks any backward-compatibility.
To make meaning of the old value, post_handler() would need access to
resume_execution() which is not exported.  I have difficulty to believe
that previous, uncorrected, regs->eip can be meaningfully used in
post_handler().

Signed-off-by: Yakov Lerner <iler.ml@gmail.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:41:13 +02:00
Jan Beulich
5b0e508415 x86: prevent unconditional writes to DebugCtl MSR
Otherwise, enabling (or better, subsequent disabling) of single
stepping would cause a kernel oops on CPUs not having this MSR.

The patch could have been added a conditional to the MSR write in
user_disable_single_step(), but centralizing the updates seems safer
and (looking forward) better manageable.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:40:58 +02:00
Harvey Harrison
f1452d424d x86, kprobes: remove sparse warnings from x86
arch/x86/kernel/kprobes.c:584:16: warning: symbol 'kretprobe_trampoline_holder' was not declared. Should it be static?
arch/x86/kernel/kprobes.c:676:6: warning: symbol 'trampoline_handler' was not declared. Should it be static?

Make them static and add the __used attribute, approach taken from the
arm kprobes implementation.

kretprobe_trampoline_holder uses inline assemly to define the global
symbol kretprobe_trampoline, but nothing ever calls the holder explicitly.

trampoline handler is only called from inline assembly in the same file,
mark it used and static.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-19 16:18:28 +01:00
Jan Engelhardt
ade1af7712 x86: remove unneded casts
x86: remove unneeded casts

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:23 +01:00
Abhishek Sagar
fb8830e72d x86: fix singlestep handling in reenter_kprobe
Highlight peculiar cases in singles-step kprobe handling.

In reenter_kprobe(), a breakpoint in KPROBE_HIT_SS case can only occur
when single-stepping a breakpoint on which a probe was installed. Since
such probes are single-stepped inline, identifying these cases is
unambiguous. All other cases leading up to KPROBE_HIT_SS are possible
bugs. Identify and WARN_ON such cases.

Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:13 +01:00
Harvey Harrison
f13bd3e793 x86: use wrmsrl in kprobes.c, step.c
Where x86_32 passed zero in the high 32 bits, use wrmsrl which
will zero extend for us.  This allows ifdefs for 32/64 bit to
be eliminated.

Eliminate ifdef in step.c.  Similar cleanup was done when unifying
kprobes_32|64.c and wrmsr() was chosen there over wrmsrl().  This
patch changes these to wrmsrl.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:12 +01:00
Harvey Harrison
1017579a8c x86: trivial whitespace in kprobes.c
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:01 +01:00
Abhishek Sagar
f315decbd0 x86: kprobes change kprobe_handler flow
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: Quentin Barnes <qbarnes@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:50 +01:00
Quentin Barnes
b506a9d08b x86: code clarification patch to Kprobes arch code
When developing the Kprobes arch code for ARM, I ran across some code
found in x86 and s390 Kprobes arch code which I didn't consider as
good as it could be.

Once I figured out what the code was doing, I changed the code
for ARM Kprobes to work the way I felt was more appropriate.
I've tested the code this way in ARM for about a year and would
like to push the same change to the other affected architectures.

The code in question is in kprobe_exceptions_notify() which
does:
====
          /* kprobe_running() needs smp_processor_id() */
          preempt_disable();
          if (kprobe_running() &&
              kprobe_fault_handler(args->regs, args->trapnr))
                  ret = NOTIFY_STOP;
          preempt_enable();
====

For the moment, ignore the code having the preempt_disable()/
preempt_enable() pair in it.

The problem is that kprobe_running() needs to call smp_processor_id()
which will assert if preemption is enabled.  That sanity check by
smp_processor_id() makes perfect sense since calling it with preemption
enabled would return an unreliable result.

But the function kprobe_exceptions_notify() can be called from a
context where preemption could be enabled.  If that happens, the
assertion in smp_processor_id() happens and we're dead.  So what
the original author did (speculation on my part!) is put in the
preempt_disable()/preempt_enable() pair to simply defeat the check.

Once I figured out what was going on, I considered this an
inappropriate approach.  If kprobe_exceptions_notify() is called
from a preemptible context, we can't be in a kprobe processing
context at that time anyways since kprobes requires preemption to
already be disabled, so just check for preemption enabled, and if
so, blow out before ever calling kprobe_running().  I wrote the ARM
kprobe code like this:
====
          /* To be potentially processing a kprobe fault and to
           * trust the result from kprobe_running(), we have
           * be non-preemptible. */
          if (!preemptible() && kprobe_running() &&
              kprobe_fault_handler(args->regs, args->trapnr))
                  ret = NOTIFY_STOP;
====

The above code has been working fine for ARM Kprobes for a year.
So I changed the x86 code (2.6.24-rc6) to be the same way and ran
the Systemtap tests on that kernel.  As on ARM, Systemtap on x86
comes up with the same test results either way, so it's a neutral
external functional change (as expected).

This issue has been discussed previously on linux-arm-kernel and the
Systemtap mailing lists.  Pointers to the by base for the two
discussions:
http://lists.arm.linux.org.uk/lurker/message/20071219.223225.1f5c2a5e.en.html
http://sourceware.org/ml/systemtap/2007-q1/msg00251.html

Signed-off-by: Quentin Barnes <qbarnes@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ananth N Mavinakayahanalli <ananth@in.ibm.com>
Acked-by: Ananth N Mavinakayahanalli <ananth@in.ibm.com>
2008-01-30 13:32:32 +01:00
Harvey Harrison
b976015637 x86: kprobes change kprobe_handler flow
Make the control flow of kprobe_handler more obvious.

Collapse the separate if blocks/gotos with if/else blocks
this unifies the duplication of the check for a breakpoint
instruction race with another cpu.

Create two jump targets:
	preempt_out: re-enables preemption before returning ret
	out: only returns ret

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:19 +01:00
Harvey Harrison
31f80e45ea x86: kprobes remove fix_riprel #ifdef
Move #ifdef around function definiton into the function and
unconditionally return on X86_32.  Saves an ifdef from the
one callsite.

[ mingo@elte.hu: minor cleanup. ]

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:16 +01:00
Harvey Harrison
9930927f36 x86: introduce REX prefix helper for kprobes
Fold some small ifdefs into a helper function.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:14 +01:00
Masami Hiramatsu
59e87cdcd2 x86: move deeply indented code to reenter_kprobe
Move some deeply indented code related to re-entrance processing
from kprobe_handler() to reenter_kprobe().

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:02 +01:00
Harvey Harrison
40102d4a41 x86: add reenter_kprobe helper
[ mhiramat@redhat.com: updated it to latest x86.git ]

Factor common X86_32, X86_64 kprobe reenter logic from deeply
indented section to helper function.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
2008-01-30 13:32:02 +01:00