Once xmon is triggered by sysrq-x, it is enabled always afterwards even
if it is disabled during boot. This will cause a system reset interrupt
fail to dump. So keep xmon in its original state after exit.

We have several ways to set xmon on or off.
1) by a build config CONFIG_XMON_DEFAULT.
2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon
and xmon=off to disable xmon. This value will override that in step 1.
3) by a debugfs interface, as proposed in this patchset.
And this value can override those in step 1 and 2.
Signed-off-by: NPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: NGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

show_mem() allows to filter out node specific data which is irrelevant
to the allocation request via SHOW_MEM_FILTER_NODES.  The filtering is
done in skip_free_areas_node which skips all nodes which are not in the
mems_allowed of the current process.  This works most of the time as
expected because the nodemask shouldn't be outside of the allocating
task but there are some exceptions.  E.g.  memory hotplug might want to
request allocations from outside of the allowed nodes (see
new_node_page).

Get rid of this hardcoded behavior and push the allocation mask down the
show_mem path and use it instead of cpuset_current_mems_allowed.  NULL
nodemask is interpreted as cpuset_current_mems_allowed.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170117091543.25850-5-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Extend the dump command to allow display of 2, 4, and 8 byte words in
CPU endian format. Also adds dump command for "1 byte values" for the
sake of symmetry. New commands are:

  d1	dump 1 byte values
  d2	dump 2 byte values
  d4	dump 4 byte values
  d8	dump 8 byte values
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NDouglas Miller <dougmill@linux.vnet.ibm.com>
Acked-by: NBalbir Singh <bsingharora@gmail.com>

Signed-off-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

That in order to gather all cputime accumulation to the same place.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1483636310-6557-7-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

In order to prepare for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y to delay
cputime accounting to the tick, provide finegrained accumulators to
powerpc in order to store the cputime until flushing.

While at it, normalize the name of several fields according to common
cputime naming.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1483636310-6557-6-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

There is a nice interface for asking ftrace to dump all its tracing
buffers. The only down side for use in xmon is that it uses printk.
Depending on circumstances printk may not work when in xmon, but it also
may, so add a 'dt' command which dumps the ftrace buffers, and add a
note to the help to mentiont that it uses printk.

Calling this routine also disables tracing, which is problematic if you
return from xmon and expect the system to keep operating normally. So
after we do the dump turn tracing back on.

Both functions already have nop versions defined for when ftrace is not
enabled, so we don't need any extra #ifdefs.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Purely to make it pleasing to the eye.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

None of these are used, or have been since we merged ppc & ppc64.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture.
PPC32 doesn't have the PACA structure, so we use the task_info
structure to store the accounting data.

In order to reuse on PPC32 the PPC64 functions, all u64 data has
been replaced by 'unsigned long' so that it is u32 on PPC32 and
u64 on PPC64
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NScott Wood <oss@buserror.net>

xmon has commands for reading and writing SPRs, but they don't work
currently for several reasons. They attempt to synthesize a small
function containing an mfspr or mtspr instruction and call it. However,
the instructions are on the stack, which is usually not executable.
Also, for 64-bit we set up a procedure descriptor, which is fine for the
big-endian ABIv1, but not correct for ABIv2. Finally, the code uses the
infrastructure for catching memory errors, but that only catches data
storage interrupts and machine check interrupts, but a failed
mfspr/mtspr can generate a program interrupt or a hypervisor emulation
assist interrupt, or be a no-op.

Instead of trying to synthesize a function on the fly, this adds two new
functions, xmon_mfspr() and xmon_mtspr(), which take an SPR number as an
argument and read or write the SPR. Because there is no Power ISA
instruction which takes an SPR number in a register, we have to generate
one of each possible mfspr and mtspr instruction, for all 1024 possible
SPRs. Thus we get just over 8k bytes of code for each of xmon_mfspr()
and xmon_mtspr(). However, this 16kB of code pales in comparison to the
> 130kB of PPC opcode tables used by the xmon disassembler.

To catch interrupts caused by the mfspr/mtspr instructions, we add a new
'catch_spr_faults' flag. If an interrupt occurs while it is set, we come
back into xmon() via program_check_interrupt(), _exception() and die(),
see that catch_spr_faults is set and do a longjmp to bus_error_jmp, back
into read_spr() or write_spr().

This adds a couple of other nice features: first, a "Sa" command that
attempts to read and print out the value of all 1024 SPRs. If any mfspr
instruction acts as a no-op, then the SPR is not implemented and not
printed.

Secondly, the Sr and Sw commands detect when an SPR is not
implemented (i.e. mfspr is a no-op) and print a message to that effect
rather than printing a bogus value.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We also use MMU_FTR_RADIX to branch out from code path specific to
hash.

No functionality change.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Add 'P' command with optional task_struct address to dump all/one task's
information: task pointer, kernel stack pointer, PID, PPID, state
(interpreted), CPU where (last) running, and command.
Signed-off-by: NDouglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Add the 'do' command to dump the OPAL msglog in xmon.
Signed-off-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
[mpe: Reduce the amount of ifdefery required]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Avoid open coding the logic by using rtas_call_unlocked().
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently if you are in xmon without an oops etc. to view the kernel
version you have to type "d $linux_banner" - not necessarily obvious. As
this is useful information, append to the output of "e" command.

Example output:
  $mon> e
  cpu 0x1: Vector: 0  at [c0000000f879ba80]
      pc: c000000000081718: sysrq_handle_xmon+0x68/0x80
      lr: c000000000081718: sysrq_handle_xmon+0x68/0x80
      sp: c0000000f879bbe0
     msr: 8000000000009033
    current = 0xc0000000f604d5c0
    paca    = 0xc00000000fdc0480	 softe: 0	 irq_happened: 0x01
      pid   = 2467, comm = bash
  Linux version 4.4.0-rc2-00008-gc51af91c3ab3-dirty (rashmica@circle) (gcc
  version 5.1.1 20150629 (GCC) ) #45 SMP Wed Nov 25 10:25:12 AEDT 2015
Signed-off-by: NRashmica Gupta <rashmicy@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch adds a set of new elements to the existing PACA dump list
inside an xmon session which can be listed below improving the overall
xmon debug support.

With this patch, a typical xmon PACA dump looks something like this.

paca for cpu 0x0 @ c00000000fdc0000:
 possible             = yes
 present              = yes
 online               = yes
 lock_token           = 0x8000            	(0xa)
 paca_index           = 0x0               	(0x8)
 kernel_toc           = 0xc000000001393200	(0x10)
 kernelbase           = 0xc000000000000000	(0x18)
 kernel_msr           = 0xb000000000001033	(0x20)
 emergency_sp         = 0xc00000003fff0000	(0x28)
 mc_emergency_sp      = 0xc00000003ffec000	(0x2e0)
 in_mce               = 0x0               	(0x2e8)
 hmi_event_available  = 0x0               	(0x2ea)
 data_offset          = 0x1fe7b0000       	(0x30)
 hw_cpu_id            = 0x0               	(0x38)
 cpu_start            = 0x1               	(0x3a)
 kexec_state          = 0x0               	(0x3b)
 slb_shadow[0]:       = 0xc000000008000000 0x40016e7779000510
 slb_shadow[1]:       = 0xd000000008000001 0x400142add1000510
 vmalloc_sllp         = 0x510             	(0x1b8)
 slb_cache_ptr        = 0x4               	(0x1ba)
 slb_cache[0]:        = 0x000000000003f000
 slb_cache[1]:        = 0x0000000000000001
 slb_cache[2]:        = 0x0000000000000003
 slb_cache[3]:        = 0x0000000000001000
 slb_cache[4]:        = 0x0000000000001000
 slb_cache[5]:        = 0x0000000000000000
 slb_cache[6]:        = 0x0000000000000000
 slb_cache[7]:        = 0x0000000000000000
 dscr_default         = 0x0               	(0x58)
 __current            = 0xc000000001331e80	(0x290)
 kstack               = 0xc000000001393e30	(0x298)
 stab_rr              = 0x11              	(0x2a0)
 saved_r1             = 0xc0000001fffef5e0	(0x2a8)
 trap_save            = 0x0               	(0x2b8)
 soft_enabled         = 0x0               	(0x2ba)
 irq_happened         = 0x1               	(0x2bb)
 io_sync              = 0x0               	(0x2bc)
 irq_work_pending     = 0x0               	(0x2bd)
 nap_state_lost       = 0x0               	(0x2be)
 sprg_vdso            = 0x0               	(0x2c0)
 tm_scratch           = 0x8000000100009033	(0x2c8)
 core_idle_state_ptr  = (null)            	(0x2d0)
 thread_idle_state    = 0x0               	(0x2d8)
 thread_mask          = 0x0               	(0x2d9)
 subcore_sibling_mask = 0x0               	(0x2da)
 user_time            = 0x0               	(0x2f0)
 system_time          = 0x0               	(0x2f8)
 user_time_scaled     = 0x0               	(0x300)
 starttime            = 0x3f462418b5cf4   	(0x308)
 starttime_user       = 0x3f4622a57092a   	(0x310)
 startspurr           = 0xd62a5718        	(0x318)
 utime_sspurr         = 0x0               	(0x320)
 stolen_time          = 0x0               	(0x328)
Signed-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Endian swap slb_shadow before display, minor formatting]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The kernel log buffer is often much longer than the size of a terminal
so paginate it's output.
Signed-off-by: NSam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The paca display is already more than 24 lines, which can be problematic
if you have an old school 80x24 terminal, or more likely you are on a
virtual terminal which does not scroll for whatever reason.

This patch adds a new command "#", which takes a single (hex) numeric
argument: lines per page. It will cause the output of "dp" and "dpa"
to be broken into pages, if necessary.

Sample output:

0:mon> # 10
0:mon> dp1
paca for cpu 0x1 @ c00000000fdc0480:
 possible         = yes
 present          = yes
 online           = yes
 lock_token       = 0x8000            	(0x8)
 paca_index       = 0x1               	(0xa)
 kernel_toc       = 0xc000000000eb2400	(0x10)
 kernelbase       = 0xc000000000000000	(0x18)
 kernel_msr       = 0xb000000000001032	(0x20)
 emergency_sp     = 0xc00000003ffe8000	(0x28)
 mc_emergency_sp  = 0xc00000003ffe4000	(0x2e0)
 in_mce           = 0x0               	(0x2e8)
 data_offset      = 0x7f170000        	(0x30)
 hw_cpu_id        = 0x8               	(0x38)
 cpu_start        = 0x1               	(0x3a)
 kexec_state      = 0x0               	(0x3b)
[Hit a key (a:all, q:truncate, any:next page)]
0:mon>
 __current        = 0xc00000007e696620	(0x290)
 kstack           = 0xc00000007e6ebe30	(0x298)
 stab_rr          = 0xb               	(0x2a0)
 saved_r1         = 0xc00000007ef37860	(0x2a8)
 trap_save        = 0x0               	(0x2b8)
 soft_enabled     = 0x0               	(0x2ba)
 irq_happened     = 0x1               	(0x2bb)
 io_sync          = 0x0               	(0x2bc)
 irq_work_pending = 0x0               	(0x2bd)
 nap_state_lost   = 0x0               	(0x2be)
0:mon>
Signed-off-by: NSam Bobroff <sam.bobroff@au1.ibm.com>
[mpe: Use bool, make some variables static]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The value of 'valid' is always zero when 'esid' is zero, and if 'esid'
is non-zero then the value of 'valid' is irrelevant because we are using
logical or in the if expression.

In fact 'valid' can be dropped completely from dump_segments() by
simply doing the check with SLB_ESID_V directly in the if.
Signed-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Rewrite change log]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

break; break; isn't useful.

Remove one.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The commit 3b8a3c01 ("powerpc/pseries: Fix endiannes issue in RTAS
call from xmon") was fixing an endianness issue in the call made from
xmon to RTAS.

However, as Michael Ellerman noticed, this fix was not complete, the
token value was not byte swapped. This lead to call an unexpected and
most of the time unexisting RTAS function, which is silently ignored by
RTAS.

This fix addresses this hole.
Reported-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: stable@vger.kernel.org
Signed-off-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

isxdigit() macro definition is the same.

isalnum() from linux/ctype.h will accept additional latin non-ASCII
characters. This is harmless since this macro is used in scanhex() which
parses user input.

isspace() from linux/ctype.h will accept vertical tab and form feed but
not NULL. The use of this macro is modified to accept NULL as
well. Additional characters are harmless since this macro is also only
used in scanhex().
Signed-off-by: NVincent Bernat <vincent@bernat.im>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Drop BP_IABR_TE, which though used, does not do anything useful. Rename
BP_IABR to BP_CIABR. Renumber the flags.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch enables support for hardware instruction breakpoint in xmon
on POWER8 platform with the help of a new register called the CIABR
(Completed Instruction Address Breakpoint Register). With this patch, a
single hardware instruction breakpoint can be added and cleared during
any active xmon debug session. The hardware based instruction breakpoint
mechanism works correctly with the existing TRAP based instruction
breakpoint available on xmon.

There are no powerpc CPU with CPU_FTR_IABR feature any more. This patch
has re-purposed all the existing IABR related code to work with CIABR
register based HW instruction breakpoint.

This has one odd feature, which is that when we hit a breakpoint xmon
doesn't tell us we have hit the breakpoint. This is because xmon is
expecting bp->address == regs->nip. Because CIABR fires on completition
regs->nip points to the instruction after the breakpoint. We could fix
that, but it would then confuse other parts of the xmon code which think
we need to emulate the instruction. [mpe]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAnshuman Khandual <khandual@linux.vnet.ibm.com>

On pseries system (LPAR) xmon failed to enter when running in LE mode,
system is hunging. Inititating xmon will lead to such an output on the
console:

SysRq : Entering xmon
cpu 0x15: Vector: 0  at [c0000003f39ffb10]
    pc: c00000000007ed7c: sysrq_handle_xmon+0x5c/0x70
    lr: c00000000007ed7c: sysrq_handle_xmon+0x5c/0x70
    sp: c0000003f39ffc70
   msr: 8000000000009033
  current = 0xc0000003fafa7180
  paca    = 0xc000000007d75e80	 softe: 0	 irq_happened: 0x01
    pid   = 14617, comm = bash
Bad kernel stack pointer fafb4b0 at eca7cc4
cpu 0x15: Vector: 300 (Data Access) at [c000000007f07d40]
    pc: 000000000eca7cc4
    lr: 000000000eca7c44
    sp: fafb4b0
   msr: 8000000000001000
   dar: 10000000
 dsisr: 42000000
  current = 0xc0000003fafa7180
  paca    = 0xc000000007d75e80	 softe: 0	 irq_happened: 0x01
    pid   = 14617, comm = bash
cpu 0x15: Exception 300 (Data Access) in xmon, returning to main loop
xmon: WARNING: bad recursive fault on cpu 0x15

The root cause is that xmon is calling RTAS to turn off the surveillance
when entering xmon, and RTAS is requiring big endian parameters.

This patch is byte swapping the RTAS arguments when running in LE mode.

Cc: stable@vger.kernel.org
Signed-off-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

dump_tlb_44x() is only defined when 44x=y, but the ifdef in xmon.c
checks for 4xx, leading to a build failure:

  arch/powerpc/xmon/xmon.c:912:4: error: implicit declaration of function 'dump_tlb_44x'
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The generic Linux framework to power off the machine is a function pointer
called pm_power_off. The trick about this pointer is that device drivers can
potentially implement it rather than board files.

Today on powerpc we set pm_power_off to invoke our generic full machine power
off logic which then calls ppc_md.power_off to invoke machine specific power
off.

However, when we want to add a power off GPIO via the "gpio-poweroff" driver,
this card house falls apart. That driver only registers itself if pm_power_off
is NULL to ensure it doesn't override board specific logic. However, since we
always set pm_power_off to the generic power off logic (which will just not
power off the machine if no ppc_md.power_off call is implemented), we can't
implement power off via the generic GPIO power off driver.

To fix this up, let's get rid of the ppc_md.power_off logic and just always use
pm_power_off as was intended. Then individual drivers such as the GPIO power off
driver can implement power off logic via that function pointer.

With this patch set applied and a few patches on top of QEMU that implement a
power off GPIO on the virt e500 machine, I can successfully turn off my virtual
machine after halt.
Signed-off-by: NAlexander Graf <agraf@suse.de>
[mpe: Squash into one patch and update changelog based on cover letter]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

xmon only soft disables interrupts. This seems like a bad idea - we
certainly don't want decrementer and PMU exceptions going off when
we are debugging something inside xmon.

This issue was uncovered when the hard lockup detector went off
inside xmon. To ensure we wont get a spurious hard lockup warning,
I also call touch_nmi_watchdog() when exiting xmon.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We now only support cpus that use an SLB, so we don't need an MMU
feature to indicate that.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

There are a couple of places where xmon is using %x to print values that
are unsigned long.

I found this out the hard way recently:

 0:mon> p c000000000d0e7c8 c00000033dc90000 00000000a0000089 c000000000000000
 return value is 0x96300500

Which is calling find_linux_pte_or_hugepte(), the result should be a
kernel pointer. After decoding the page tables by hand I discovered the
correct value was c000000396300500.

So fix up that case and a few others.

We also use a mix of 0x%x, %x and %u to print cpu numbers. So
standardise on 0x%x.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently, on 8641D, which doesn't set CONFIG_HAVE_HW_BREAKPOINT
we get the following splat:

BUG: using smp_processor_id() in preemptible [00000000] code: login/1382
caller is set_breakpoint+0x1c/0xa0
CPU: 0 PID: 1382 Comm: login Not tainted 3.15.0-rc3-00041-g2aafe1a4 #1
Call Trace:
[decd5d80] [c0008dc4] show_stack+0x50/0x158 (unreliable)
[decd5dc0] [c03c6fa0] dump_stack+0x7c/0xdc
[decd5de0] [c01f8818] check_preemption_disabled+0xf4/0x104
[decd5e00] [c00086b8] set_breakpoint+0x1c/0xa0
[decd5e10] [c00d4530] flush_old_exec+0x2bc/0x588
[decd5e40] [c011c468] load_elf_binary+0x2ac/0x1164
[decd5ec0] [c00d35f8] search_binary_handler+0xc4/0x1f8
[decd5ef0] [c00d4ee8] do_execve+0x3d8/0x4b8
[decd5f40] [c001185c] ret_from_syscall+0x0/0x38
 --- Exception: c01 at 0xfeee554
    LR = 0xfeee7d4

The call path in this case is:

	flush_thread
	   --> set_debug_reg_defaults
	     --> set_breakpoint
	       --> __get_cpu_var

Since preemption is enabled in the cleanup of flush thread, and
there is no need to disable it, introduce the distinction between
set_breakpoint and __set_breakpoint, leaving only the flush_thread
instance as the current user of set_breakpoint.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch fixes the disassembler of the powerpc kernel debugger xmon,
for little-endian.
Signed-off-by: NPhilippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently we set our cpu's bit in cpus_in_xmon, and then we take the
output lock and print the exception information.

This can race with the master cpu entering the command loop and printing
the backtrace. The result is that the backtrace gets garbled with
another cpu's exception print out.

Fix it by delaying the set of cpus_in_xmon until we are finished
printing.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>