linux-toradex.git/arch/sh/kernel/ptrace_32.c, branch v3.3.4

audit: inline audit_syscall_entry to reduce burden on archs

2012-01-17T21:16:56+00:00

Every arch calls:

if (unlikely(current->audit_context))
	audit_syscall_entry()

which requires knowledge about audit (the existance of audit_context) in
the arch code.  Just do it all in static inline in audit.h so that arch's
can remain blissfully ignorant.

Signed-off-by: Eric Paris

Audit: push audit success and retcode into arch ptrace.h

2012-01-17T21:16:56+00:00

The audit system previously expected arches calling to audit_syscall_exit to
supply as arguments if the syscall was a success and what the return code was.
Audit also provides a helper AUDITSC_RESULT which was supposed to simplify things
by converting from negative retcodes to an audit internal magic value stating
success or failure.  This helper was wrong and could indicate that a valid
pointer returned to userspace was a failed syscall.  The fix is to fix the
layering foolishness.  We now pass audit_syscall_exit a struct pt_reg and it
in turns calls back into arch code to collect the return value and to
determine if the syscall was a success or failure.  We also define a generic
is_syscall_success() macro which determines success/failure based on if the
value is < -MAX_ERRNO.  This works for arches like x86 which do not use a
separate mechanism to indicate syscall failure.

We make both the is_syscall_success() and regs_return_value() static inlines
instead of macros.  The reason is because the audit function must take a void*
for the regs.  (uml calls theirs struct uml_pt_regs instead of just struct
pt_regs so audit_syscall_exit can't take a struct pt_regs).  Since the audit
function takes a void* we need to use static inlines to cast it back to the
arch correct structure to dereference it.

The other major change is that on some arches, like ia64, MIPS and ppc, we
change regs_return_value() to give us the negative value on syscall failure.
THE only other user of this macro, kretprobe_example.c, won't notice and it
makes the value signed consistently for the audit functions across all archs.

In arch/sh/kernel/ptrace_64.c I see that we were using regs[9] in the old
audit code as the return value.  But the ptrace_64.h code defined the macro
regs_return_value() as regs[3].  I have no idea which one is correct, but this
patch now uses the regs_return_value() function, so it now uses regs[3].

For powerpc we previously used regs->result but now use the
regs_return_value() function which uses regs->gprs[3].  regs->gprs[3] is
always positive so the regs_return_value(), much like ia64 makes it negative
before calling the audit code when appropriate.

Signed-off-by: Eric Paris 
Acked-by: H. Peter Anvin  [for x86 portion]
Acked-by: Tony Luck  [for ia64]
Acked-by: Richard Weinberger  [for uml]
Acked-by: David S. Miller  [for sparc]
Acked-by: Ralf Baechle  [for mips]
Acked-by: Benjamin Herrenschmidt  [for ppc]

perf: Add context field to perf_event

2011-07-01T09:06:38+00:00

The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure.  This is ugly and doesn't scale if a
single callback services many perf_events.

Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.

Signed-off-by: Avi Kivity 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar

perf: Remove the nmi parameter from the swevent and overflow interface

2011-07-01T09:06:35+00:00

The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

  - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
    the PMI-tail (ARM etc.)
  - tracepoint: nmi=0; since tracepoint could be from NMI context.
  - software: nmi=[0,1]; some, like the schedule thing cannot
    perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.

Signed-off-by: Peter Zijlstra 
Cc: Michael Cree 
Cc: Will Deacon 
Cc: Deng-Cheng Zhu 
Cc: Anton Blanchard 
Cc: Eric B Munson 
Cc: Heiko Carstens 
Cc: Paul Mundt 
Cc: David S. Miller 
Cc: Frederic Weisbecker 
Cc: Jason Wessel 
Cc: Don Zickus 
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
Signed-off-by: Ingo Molnar

sh, hw_breakpoints: Fix racy access to ptrace breakpoints

2011-04-25T15:36:12+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: Paul Mundt 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Will Deacon 
Cc: Prasad 
Link: http://lkml.kernel.org/r/1302284067-7860-6-git-send-email-fweisbec@gmail.com

sh: Fix ptrace hw_breakpoint handling

2011-03-23T13:18:25+00:00

Since commit 34d0b5af50a063cded842716633501b38ff815fb it is no longer
possible to debug an application using singlestep. The old commit
converted singlestep handling via ptrace to hw_breakpoints. The
hw_breakpoint is disabled when an event is triggered and not re-enabled
again. This patch re-enables the existing hw_breakpoint before the
existing breakpoint is reused.

Signed-off-by: David Engraf 
Cc: stable@kernel.org
Signed-off-by: Paul Mundt

sh: Fix ptrace fpu state initialisation

2011-03-23T13:17:52+00:00

Commit 0ea820cf introduced the PTRACE_GETFPREGS/SETFPREGS cmds,
but gdb-server still accesses the FPU state using the
PTRACE_PEEKUSR/POKEUSR commands. In this case, xstate was not
initialised.

Signed-off-by: Phil Edworthy 
Cc: stable@kernel.org
Signed-off-by: Paul Mundt

ptrace: cleanup arch_ptrace() on sh

2010-10-28T01:03:12+00:00

Remove unnecessary castings and get rid of dummy pointer in favor of
offsetof() macro in ptrace_32.c. Also use temporary variables and
break long lines in order to improve readability.

Signed-off-by: Namhyung Kim 
Cc: Paul Mundt 
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

sh: Add kprobe-based event tracer.

2010-06-14T06:16:53+00:00

This follows the x86/ppc changes for kprobe-based event tracing on sh.
While kprobes is only supported on 32-bit sh, we provide the API for
HAVE_REGS_AND_STACK_ACCESS_API for both 32 and 64-bit.

Signed-off-by: Paul Mundt