linux.git/arch/powerpc/kernel/ptrace.c, branch v3.0.14

powerpc/ftrace: Implement raw syscall tracepoints on PowerPC

2011-05-26T03:38:57+00:00

This patch implements the raw syscall tracepoints on PowerPC and exports
them for ftrace syscalls to use.

To minimise reworking existing code, I slightly re-ordered the thread
info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit
within the 16 bits of the andi. instruction's UI field. The instructions
in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the
_TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing
is enabled.

In the case of 64bit PowerPC, arch_syscall_addr and
arch_syscall_match_sym_name are overridden to allow ftrace syscalls to
work given the unusual system call table structure and symbol names that
start with a period.

Signed-off-by: Ian Munsie 
Signed-off-by: Benjamin Herrenschmidt

hw_breakpoints, powerpc: Fix CONFIG_HAVE_HW_BREAKPOINT off-case in ptrace_set_debugreg()

2011-05-06T09:24:46+00:00

We make use of ptrace_get_breakpoints() / ptrace_put_breakpoints() to
protect ptrace_set_debugreg() even if CONFIG_HAVE_HW_BREAKPOINT if off.
However in this case, these APIs are not implemented.

To fix this, push the protection down inside the relevant ifdef.
Best would be to export the code inside
CONFIG_HAVE_HW_BREAKPOINT into a standalone function to cleanup
the ifdefury there and call the breakpoint ref API inside. But
as it is more invasive, this should be rather made in an -rc1.

Fixes this build error:

  arch/powerpc/kernel/ptrace.c:1594: error: implicit declaration of function 'ptrace_get_breakpoints' make[2]: ***

Reported-by: Ingo Molnar 
Signed-off-by: Frederic Weisbecker 
Cc: LPPC 
Cc: Prasad 
Cc: v2.6.33.. 
Link: http://lkml.kernel.org/r/1304639598-4707-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar

powerpc, hw_breakpoints: Fix racy access to ptrace breakpoints

2011-04-25T15:33:54+00:00

While the tracer accesses ptrace breakpoints, the child task may
concurrently exit due to a SIGKILL and thus release its breakpoints
at the same time. We can then dereference some freed pointers.

To fix this, hold a reference on the child breakpoints before
manipulating them.

Reported-by: Oleg Nesterov 
Signed-off-by: Frederic Weisbecker 
Acked-by: Prasad 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Will Deacon 
Cc: Paul Mundt 
Cc: v2.6.33.. 
Link: http://lkml.kernel.org/r/1302284067-7860-4-git-send-email-fweisbec@gmail.com

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

powerpc/ptrace: Remove BUG_ON when full register set not available

2011-03-21T00:18:14+00:00

In some cases during a threaded core dump not all the threads will have
a full register set. This happens when the signal causing the core dump
races with a thread exiting.  The race happens when the exiting thread
has entered the kernel for the last time before the signal arrives, but
doesn't get far enough through the exit code to avoid being included
in the core dump.

So we get a thread included in the core dump which is never going to go
out to userspace again and only has a partial register set recorded

Normally we would catch each thread as it is about to go into userspace
and capture the full register set then.

However, this exiting thread is never going to go out to userspace
again, so we have no way to capture its full register set.  It doesn't
really matter, though, as this is a thread which is effectively
already dead.

So instead of hitting a BUG() in this case (a really bad choice of
action in the first place), we use a poison value for the register
values.

[BenH]: Some cosmetic/stylistic changes and fix build on ppc32

Signed-off-by: Mike Wolf 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix PPC_PTRACE_SETHWDEBUG on PPC_BOOK3S

2010-12-09T04:35:31+00:00

Properly set the DABR_TRANSLATION/DABR_DATA_READ/DABR_DATA_READ bits in
the dabr when setting the debug register via PPC_PTRACE_SETHWDEBUG.  Also
don't reject trigger type of PPC_BREAKPOINT_TRIGGER_READ.

Signed-off-by: Andreas Schwab 
Signed-off-by: Benjamin Herrenschmidt

ptrace: cleanup arch_ptrace() on powerpc

2010-10-28T01:03:11+00:00

Use new 'datavp' and 'datalp' variables in order to remove unnecessary
castings.

Signed-off-by: Namhyung Kim 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: change signature of arch_ptrace()

2010-10-28T01:03:10+00:00

Fix up the arguments to arch_ptrace() to take account of the fact that
@addr and @data are now unsigned long rather than long as of a preceding
patch in this series.

Signed-off-by: Namhyung Kim 
Cc: 
Acked-by: Roland McGrath 
Acked-by: David Howells 
Acked-by: Geert Uytterhoeven 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

powerpc: Use is_32bit_task() helper to test 32-bit binary

2010-09-02T04:07:32+00:00

This patch removes all explicit tests for the TIF_32BIT flag

Signed-off-by: Denis Kirjanov 
Signed-off-by: Benjamin Herrenschmidt

powerpc, hw_breakpoints: Implement hw_breakpoints for 64-bit server processors

2010-06-22T09:40:50+00:00

Implement perf-events based hw-breakpoint interfaces for PowerPC
64-bit server (Book III S) processors.  This allows access to a
given location to be used as an event that can be counted or
profiled by the perf_events subsystem.

This is done using the DABR (data breakpoint register), which can
also be used for process debugging via ptrace.  When perf_event
hw_breakpoint support is configured in, the perf_event subsystem
manages the DABR and arbitrates access to it, and ptrace then
creates a perf_event when it is requested to set a data breakpoint.

[Adopted suggestions from Paul Mackerras  to
- emulate_step() all system-wide breakpoints and single-step only the
  per-task breakpoints
- perform arch-specific cleanup before unregistration through
  arch_unregister_hw_breakpoint()
]

Signed-off-by: K.Prasad 
Signed-off-by: Paul Mackerras