Currently we are getting:
 arch/powerpc/kernel/kgdb.c: In function 'kgdb_arch_exit':
 arch/powerpc/kernel/kgdb.c:492:2: error: '__debugger_breakx_match' undeclared (first use in this function)
 arch/powerpc/kernel/kgdb.c:492:2: note: each undeclared identifier is reported only once for each function it appears in

Fix the typo.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This is a rewrite so that we don't assume we are using the DABR throughout the
code.  We now use the arch_hw_breakpoint to store the breakpoint in a generic
manner in the thread_struct, rather than storing the raw DABR value.

The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from
userspace.  We keep this functionality, so that future changes (like the POWER8
DAWR), will still fake the DABR to userspace.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

For powerpc BooKE and e200, singlestep is handled on the critical/dbg
exception stack. This causes current_thread_info() to fail for kgdb
internal, so previously We work around this issue by copying
the thread_info from the kernel stack before calling kgdb_handle_exception,
and copying it back afterwards.

But actually we don't do this properly. We should backup current_thread_info
then restore that when exit.
Signed-off-by: NTiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We need to skip a breakpoint exception when it occurs after
a breakpoint has already been removed.
Signed-off-by: NTiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The kgdb_single_step flag has the possibility to indefinitely
hang the system on an SMP system.

The x86 arch have the same problem, and that problem was fixed by
commit 8097551d(kgdb,x86: do not set kgdb_single_step
on x86). This patch does the same behaviors as x86's patch.
Signed-off-by: NDongdong Deng <dongdong.deng@windriver.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The only user of MSG_ALL_BUT_SELF in the whole kernel tree is powerpc,
and it only uses it to start the debugger. Both debuggers always call
smp_send_debugger_break with MSG_ALL_BUT_SELF, and only mpic can do
anything more optimal than a loop over all online cpus, but all message
passing implementations have to code for this special delivery target.

Convert smp_send_debugger_break to take void and loop calling the smp_ops
message_pass function for each of the other cpus in the online cpumask.

Use raw_smp_processor_id() because we are either entering the debugger
or trying to start kdump and the additional warning it not useful were
it to trigger.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Commit ff10b88b (kgdb,ppc: Individual
register get/set for ppc) introduced a problem where memcpy was used
incorrectly to read and write the evr registers with a kernel that
has:

CONFIG_FSL_BOOKE=y
CONFIG_SPE=y
CONFIG_KGDB=y

This patch also fixes the following compilation problems:

arch/powerpc/kernel/kgdb.c: In function 'dbg_get_reg':
arch/powerpc/kernel/kgdb.c:341: error: passing argument 2 of 'memcpy' makes pointer from integer without a cast
arch/powerpc/kernel/kgdb.c: In function 'dbg_set_reg':
arch/powerpc/kernel/kgdb.c:366: error: passing argument 1 of 'memcpy' makes pointer from integer without a cast

[jason.wessel@windriver.com: Remove void * casts and fix patch header]
Reported-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NDongdong Deng <dongdong.deng@windriver.com>
Acked-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
CC: linuxppc-dev@lists.ozlabs.org

commit 534af108(kgdb,kdb: individual
register set and and get API) introduce dbg_get_reg/dbg_set_reg API
for individual register get and set.

This patch implement those APIs for ppc.
Signed-off-by: NDongdong Deng <dongdong.deng@windriver.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

kgdb_handle_breakpoint checks the first arch_kgdb_breakpoint
which is not known by gdb that's why is necessary jump over
it. The jump lenght is equal to BREAK_INSTR_SIZE that's
why is cleaner to use defined macro instead of hardcoded
non-described offset.
Signed-off-by: NMichal Simek <monstr@monstr.eu>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The only way the debugger can handle a trap in inside rcu_lock,
notify_die, or atomic_notifier_call_chain without a recursive fault is
to allow the kernel debugger to handle the exception first in
program_check_exception().

The other change here is to make sure that kgdb_handle_exception() is
called with correct parameters when catching an oops, because kdb
needs to know if the entry was an oops, single step, or breakpoint
exception.

[benh@kernel.crashing.org: move debugger_bpt instead of #ifdef]

CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

These are the minimum changes to the kgdb core in order to enable an
API to connect a new front end (kdb) to the debug core.

This patch introduces the dbg_kdb_mode variable controls where the
user level I/O is routed.  It will be routed to the gdbstub (kgdb) or
to the kdb front end which is a simple shell available over the kgdboc
connection.

You can switch back and forth between kdb or the gdb stub mode of
operation dynamically.  From gdb stub mode you can blindly type
"$3#33", or from the kdb mode you can enter "kgdb" to switch to the
gdb stub.

The logic in the debug core depends on kdb to look for the typical gdb
connection sequences and return immediately with KGDB_PASS_EVENT if a
gdb serial command sequence is detected.  That should allow a
reasonably seamless transition between kdb -> gdb without leaving the
kernel exception state.  The two gdb serial queries that kdb is
responsible for detecting are the "?" and "qSupported" packets.

CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NMartin Hicks <mort@sgi.com>

powerpc/booke: Introduce new CONFIG options for advanced debug registers

From: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

Introduce new config options to simplify the ifdefs pertaining to the
advanced debug registers for booke and 40x processors:

CONFIG_PPC_ADV_DEBUG_REGS - boolean: true for dac-based processors
CONFIG_PPC_ADV_DEBUG_IACS - number of IAC registers
CONFIG_PPC_ADV_DEBUG_DACS - number of DAC registers
CONFIG_PPC_ADV_DEBUG_DVCS - number of DVC registers
CONFIG_PPC_ADV_DEBUG_DAC_RANGE - DAC ranges supported

Beginning conservatively, since I only have the facilities to test 440
hardware.  I believe all 40x and booke platforms support at least 2 IAC
and 2 DAC registers.  For 440, 4 IAC and 2 DVC registers are enabled, as
well as the DAC ranges.
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

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: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

'acc' isn't used anywhere and thus triggers gcc warning, which causes
build error with CONFIG_PPC_DISABLE_WERROR=n (default):

  cc1: warnings being treated as errors
  arch/powerpc/kernel/kgdb.c: In function 'gdb_regs_to_pt_regs':
  arch/powerpc/kernel/kgdb.c:289: warning: unused variable 'acc'
  make[1]: *** [arch/powerpc/kernel/kgdb.o] Error 1
Signed-off-by: NAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On the x86 arch, user space single step exceptions should be ignored
if they occur in the kernel space, such as ptrace stepping through a
system call.

First check if it is kgdb that is executing a single step, then ensure
it is not an accidental traversal into the user space, while in kgdb,
any other time the TIF_SINGLESTEP is set, kgdb should ignore the
exception.

On x86, arm, mips and powerpc, the kgdb_contthread usage was
inconsistent with the way single stepping is implemented in the kgdb
core.  The arch specific stub should always set the
kgdb_cpu_doing_single_step correctly if it is single stepping.  This
allows kgdb to correctly process an instruction steps if ptrace
happens to be requesting an instruction step over a system call.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

This patch removes the old kgdb reminants from ARCH=powerpc and
implements the new style arch specific stub for the common kgdb core
interface.

It is possible to have xmon and kgdb in the same kernel, but you
cannot use both at the same time because there is only one set of
debug hooks.

The arch specific kgdb implementation saves the previous state of the
debug hooks and restores them if you unconfigure the kgdb I/O driver.
Kgdb should have no impact on a kernel that has no kgdb I/O driver
configured.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>