Commit Graph

141 Commits

Author SHA1 Message Date
Guilherme G. Piccoli de78ae6c9e powerpc/xmon: add debugfs entry for xmon
Currently the xmon debugger is set only via kernel boot command-line.
It's disabled by default, and can be enabled with "xmon=on" on the
command-line. Also, xmon may be accessed via sysrq mechanism.
But we cannot enable/disable xmon in runtime, it needs kernel reload.

This patch introduces a debugfs entry for xmon, allowing user to query
its current state and change it if desired. Basically, the "xmon" file
to read from/write to is under the debugfs mount point, on powerpc
directory. It's a simple attribute, value 0 meaning xmon is disabled
and value 1 the opposite. Writing these states to the file will take
immediate effect in the debugger.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-28 10:52:01 +11:00
Guilherme G. Piccoli b561783c7b powerpc/xmon: drop the nobt option from xmon plus minor fixes
The xmon parameter nobt was added long time ago, by commit 26c8af5f01
("[POWERPC] print backtrace when entering xmon"). The problem that time
was that during a crash in a machine with USB keyboard, xmon wouldn't
respond to commands from the keyboard, so printing the backtrace wouldn't
be possible.

Idea then was to show automatically the backtrace on xmon crash for the
first time it's invoked (if it recovers, next time xmon won't show
backtrace automatically). The nobt parameter was added _only_ to prevent
this automatic trace show. Seems long time ago USB keyboards didn't work
that well!

We don't need this parameter anymore, the feature of auto showing the
backtrace is interesting (imagine a case of auto-reboot script),
so this patch extends the functionality, by always showing the backtrace
automatically when xmon is invoked; it removes the nobt parameter too.

Also, this patch fixes __initdata placement on xmon_early and replaces
__initcall() with modern device_initcall() on sysrq handler.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-28 10:52:01 +11:00
Pan Xinhui 3b5bf42b81 powerpc/xmon: Fix an unexpected xmon on/off state change
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: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-28 10:52:00 +11:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
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: Linus 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: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Linus Torvalds b286cedd47 powerpc updates for 4.11 part 2
Highlights include:
 
  - An update of the disassembly code used by xmon to the latest versions in
    binutils. We've received permission from all the authors of the relevant
    binutils changes to relicense their changes to the relevant files from GPLv3
    to GPLv2, for inclusion in Linux. Thanks to Peter Bergner for doing the leg
    work to get permission from everyone.
 
  - Addition of the "architected" Power9 CPU table entry, allowing us to boot
    in Power9 architected mode under a hypervisor.
 
  - Updates to the Power9 PMU code.
 
  - Implementation of clear_bit_unlock_is_negative_byte() to optimise
    unlock_page().
 
  - Freescale updates from Scott: "Highlights include 8xx breakpoints and perf,
    t1042rdb display support, and board updates."
 
 Thanks to:
   Al Viro, Andrew Donnellan, Aneesh Kumar K.V, Balbir Singh, Douglas Miller,
   Frédéric Weisbecker, Gavin Shan, Madhavan Srinivasan, Michael Roth, Nathan
   Fontenot, Naveen N. Rao, Nicholas Piggin, Peter Bergner, Paul E. McKenney,
   Rashmica Gupta, Russell Currey, Sahil Mehta, Stewart Smith.
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Merge tag 'powerpc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull more powerpc updates from Michael Ellerman:
 "Highlights include:

   - an update of the disassembly code used by xmon to the latest
     versions in binutils. We've received permission from all the
     authors of the relevant binutils changes to relicense their changes
     to the relevant files from GPLv3 to GPLv2, for inclusion in Linux.
     Thanks to Peter Bergner for doing the leg work to get permission
     from everyone.

   - addition of the "architected" Power9 CPU table entry, allowing us
     to boot in Power9 architected mode under a hypervisor.

   - updates to the Power9 PMU code.

   - implementation of clear_bit_unlock_is_negative_byte() to optimise
     unlock_page().

   - Freescale updates from Scott: "Highlights include 8xx breakpoints
     and perf, t1042rdb display support, and board updates."

  Thanks to:
    Al Viro, Andrew Donnellan, Aneesh Kumar K.V, Balbir Singh, Douglas
    Miller, Frédéric Weisbecker, Gavin Shan, Madhavan Srinivasan,
    Michael Roth, Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Peter
    Bergner, Paul E. McKenney, Rashmica Gupta, Russell Currey, Sahil
    Mehta, Stewart Smith"

* tag 'powerpc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (48 commits)
  powerpc: Remove leftover cputime_to_nsecs call causing build error
  powerpc/mm/hash: Always clear UPRT and Host Radix bits when setting up CPU
  powerpc/optprobes: Fix TOC handling in optprobes trampoline
  powerpc/pseries: Advertise Hot Plug Event support to firmware
  cxl: fix nested locking hang during EEH hotplug
  powerpc/xmon: Dump memory in CPU endian format
  powerpc/pseries: Revert 'Auto-online hotplugged memory'
  powerpc/powernv: Make PCI non-optional
  powerpc/64: Implement clear_bit_unlock_is_negative_byte()
  powerpc/powernv: Remove unused variable in pnv_pci_sriov_disable()
  powerpc/kernel: Remove error message in pcibios_setup_phb_resources()
  powerpc/mm: Fix typo in set_pte_at()
  pci/hotplug/pnv-php: Disable MSI and PCI device properly
  pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts
  pci/hotplug/pnv-php: Remove WARN_ON() in pnv_php_put_slot()
  powerpc: Add POWER9 architected mode to cputable
  powerpc/perf: use is_kernel_addr macro in perf_get_misc_flags()
  powerpc/perf: Avoid FAB_*_MATCH checks for power9
  powerpc/perf: Add restrictions to PMC5 in power9 DD1
  powerpc/perf: Use Instruction Counter value
  ...
2017-03-01 10:10:16 -08:00
Michal Hocko 9af744d743 lib/show_mem.c: teach show_mem to work with the given nodemask
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.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22 16:41:30 -08:00
Linus Torvalds 38705613b7 powerpc updates for 4.11 part 1.
Highlights include:
 
  - Support for direct mapped LPC on POWER9, giving Linux direct access to
    devices that may be on there such as a UART.
 
  - Memory hotplug support for the Power9 Radix MMU.
 
  - Add new AUX vectors describing the processor's cache geometry, to be used by
    glibc.
 
  - The ability for a guest to ask the hypervisor to resize the guest's hash
    table, and in addition support for doing so automatically when memory is
    hotplugged into/out-of the guest. This allows the hash table to be sized
    based on the current memory usage of the guest, rather than the maximum
    possible memory usage.
 
  - Implementation of optprobes (kprobe optimisation) for powerpc.
 
 In addition there's the topic branch shared with the KVM tree, which includes
 support for guests to use the Radix MMU on Power9.
 
 Thanks to:
   Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T, Anton Blanchard,
   Benjamin Herrenschmidt, Chris Packham, Daniel Axtens, Daniel Borkmann, David
   Gibson, Finn Thain, Gautham R. Shenoy, Gavin Shan, Greg Kurz, Joel Stanley,
   John Allen, Madhavan Srinivasan, Mahesh Salgaonkar, Markus Elfring, Michael
   Neuling, Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Ravi
   Bangoria, Reza Arbab, Shailendra Singh, Vaibhav Jain, Wei Yongjun.
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Merge tag 'powerpc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Highlights include:

   - Support for direct mapped LPC on POWER9, giving Linux direct access
     to devices that may be on there such as a UART.

   - Memory hotplug support for the Power9 Radix MMU.

   - Add new AUX vectors describing the processor's cache geometry, to
     be used by glibc.

   - The ability for a guest to ask the hypervisor to resize the guest's
     hash table, and in addition support for doing so automatically when
     memory is hotplugged into/out-of the guest. This allows the hash
     table to be sized based on the current memory usage of the guest,
     rather than the maximum possible memory usage.

   - Implementation of optprobes (kprobe optimisation) for powerpc.

  In addition there's the topic branch shared with the KVM tree, which
  includes support for guests to use the Radix MMU on Power9.

  Thanks to:
    Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T, Anton
    Blanchard, Benjamin Herrenschmidt, Chris Packham, Daniel Axtens,
    Daniel Borkmann, David Gibson, Finn Thain, Gautham R. Shenoy, Gavin
    Shan, Greg Kurz, Joel Stanley, John Allen, Madhavan Srinivasan,
    Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Nathan Fontenot,
    Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Ravi Bangoria, Reza
    Arbab, Shailendra Singh, Vaibhav Jain, Wei Yongjun"

* tag 'powerpc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (129 commits)
  powerpc/mm/radix: Skip ptesync in pte update helpers
  powerpc/mm/radix: Use ptep_get_and_clear_full when clearing pte for full mm
  powerpc/mm/radix: Update pte update sequence for pte clear case
  powerpc/mm: Update PROTFAULT handling in the page fault path
  powerpc/xmon: Fix data-breakpoint
  powerpc/mm: Fix build break with BOOK3S_64=n and MEMORY_HOTPLUG=y
  powerpc/mm: Fix build break when CMA=n && SPAPR_TCE_IOMMU=y
  powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n
  powerpc/pseries: Fix typo in parameter description
  powerpc/kprobes: Remove kprobe_exceptions_notify()
  kprobes: Introduce weak variant of kprobe_exceptions_notify()
  powerpc/ftrace: Fix confusing help text for DISABLE_MPROFILE_KERNEL
  powerpc/powernv: Fix opal_exit tracepoint opcode
  powerpc: Add a prototype for mcount() so it can be versioned
  powerpc: Drop GPL from of_node_to_nid() export to match other arches
  powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()
  powerpc/kprobes: Implement Optprobes
  powerpc/kprobes: Fixes for kprobe_lookup_name() on BE
  powerpc: Add helper to check if offset is within relative branch range
  powerpc/bpf: Introduce __PPC_SH64()
  ...
2017-02-22 10:30:38 -08:00
Douglas Miller 5e48dc0aa4 powerpc/xmon: Dump memory in CPU endian format
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: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
2017-02-21 16:00:21 +11:00
Madhavan Srinivasan e71ff89c71 powerpc/xmon: Cleanup to use is_kernel_addr macro
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-02-02 16:44:14 +11:00
Frederic Weisbecker f828c3d0ae sched/cputime, powerpc: Migrate stolen_time field to the accounting structure
That in order to gather all cputime accumulation to the same place.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Thomas 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.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 09:54:12 +01:00
Frederic Weisbecker 8c8b73c481 sched/cputime, powerpc: Prepare accounting structure for cputime flush on tick
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: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Thomas 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.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 09:54:12 +01:00
Michael Ellerman 56144ec7c9 powerpc/xmon: Add 'dt' command to dump trace buffers
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: Michael Ellerman <mpe@ellerman.id.au>
2016-11-25 14:30:27 +11:00
Michael Ellerman 719dbb2df7 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next
Freescale updates from Scott:

"Highlights include more 8xx optimizations, device tree updates,
and MVME7100 support."
2016-07-30 13:43:19 +10:00
Michael Ellerman e0ddf7a245 powerpc/xmon: Dump ISA 2.07 SPRs
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:26:24 +10:00
Michael Ellerman 1846193b17 powerpc/xmon: Dump ISA 2.06 SPRs
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:26:24 +10:00
Michael Ellerman 56346ad88d powerpc/xmon: Adjust spacing of existing SPRs to make room for more
Purely to make it pleasing to the eye.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:26:23 +10:00
Michael Ellerman 13629dad1e powerpc/xmon: Move static regno into its only user
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:26:23 +10:00
Michael Ellerman 5b71eff782 powerpc/xmon: Remove unused externs
None of these are used, or have been since we merged ppc & ppc64.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-14 20:26:22 +10:00
Christophe Leroy c223c90386 powerpc32: provide VIRT_CPU_ACCOUNTING
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: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <oss@buserror.net>
2016-07-09 01:43:50 -05:00
Paul Mackerras 31cdd0c39c powerpc/xmon: Fix SPR read/write commands and add command to dump SPRs
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: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:54:07 +10:00
Aneesh Kumar K.V caca285e5a powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code
We also use MMU_FTR_RADIX to branch out from code path specific to
hash.

No functionality change.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:53:45 +10:00
Douglas Miller 6dfb54049f powerpc/xmon: Add xmon command to dump process/task similar to ps(1)
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: Douglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-10 10:22:04 +11:00
Andrew Donnellan fde93a0f77 powerpc/xmon: add command to dump OPAL msglog
Add the 'do' command to dump the OPAL msglog in xmon.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
[mpe: Reduce the amount of ifdefery required]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-09 21:03:39 +11:00
Andrew Donnellan 2e34057929 powerpc/xmon: fix typo in usage message
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-08 22:34:52 +11:00
Michael Ellerman 08eb105a7c powerpc/xmon: Use rtas_call_unlocked() in xmon
Avoid open coding the logic by using rtas_call_unlocked().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-17 22:40:55 +11:00
Rashmica Gupta eb925d6460 powerpc/xmon: Append linux_banner to exception information in xmon.
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: Rashmica Gupta <rashmicy@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 20:41:50 +11:00
Michael Ellerman ad987fc8ea powerpc/xmon: Add some more elements to the existing PACA dump list
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: Anshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Endian swap slb_shadow before display, minor formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-15 20:32:02 +11:00
Sam bobroff 0c23a88ccc powerpc/xmon: Paginate kernel log buffer display
The kernel log buffer is often much longer than the size of a terminal
so paginate it's output.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-15 20:32:02 +11:00
Sam bobroff 958b7c8050 powerpc/xmon: Paged output for paca display
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: Sam Bobroff <sam.bobroff@au1.ibm.com>
[mpe: Use bool, make some variables static]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-15 20:32:01 +11:00
Anshuman Khandual 8218a3031c powerpc/xmon: Drop the valid variable completely in dump_segments()
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: Anshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-08-12 15:05:47 +10:00
Joe Perches a825ac078b powerpc: Remove redundant breaks
break; break; isn't useful.

Remove one.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-08-06 15:10:20 +10:00
Linus Torvalds d3f180ea1a powerpc updates for 3.20
Including:
 
 - Update of all defconfigs
 - Addition of a bunch of config options to modernise our defconfigs
 - Some PS3 updates from Geoff
 - Optimised memcmp for 64 bit from Anton
 - Fix for kprobes that allows 'perf probe' to work from Naveen
 - Several cxl updates from Ian & Ryan
 - Expanded support for the '24x7' PMU from Cody & Sukadev
 - Freescale updates from Scott:
   "Highlights include 8xx optimizations, some more work on datapath device
    tree content, e300 machine check support, t1040 corenet error reporting,
    and various cleanups and fixes."
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Merge tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

Pull powerpc updates from Michael Ellerman:

 - Update of all defconfigs

 - Addition of a bunch of config options to modernise our defconfigs

 - Some PS3 updates from Geoff

 - Optimised memcmp for 64 bit from Anton

 - Fix for kprobes that allows 'perf probe' to work from Naveen

 - Several cxl updates from Ian & Ryan

 - Expanded support for the '24x7' PMU from Cody & Sukadev

 - Freescale updates from Scott:
    "Highlights include 8xx optimizations, some more work on datapath
     device tree content, e300 machine check support, t1040 corenet
     error reporting, and various cleanups and fixes"

* tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (102 commits)
  cxl: Add missing return statement after handling AFU errror
  cxl: Fail AFU initialisation if an invalid configuration record is found
  cxl: Export optional AFU configuration record in sysfs
  powerpc/mm: Warn on flushing tlb page in kernel context
  powerpc/powernv: Add OPAL soft-poweroff routine
  powerpc/perf/hv-24x7: Document sysfs event description entries
  powerpc/perf/hv-gpci: add the remaining gpci requests
  powerpc/perf/{hv-gpci, hv-common}: generate requests with counters annotated
  powerpc/perf/hv-24x7: parse catalog and populate sysfs with events
  perf: define EVENT_DEFINE_RANGE_FORMAT_LITE helper
  perf: add PMU_EVENT_ATTR_STRING() helper
  perf: provide sysfs_show for struct perf_pmu_events_attr
  powerpc/kernel: Avoid initializing device-tree pointer twice
  powerpc: Remove old compile time disabled syscall tracing code
  powerpc/kernel: Make syscall_exit a local label
  cxl: Fix device_node reference counting
  powerpc/mm: bail out early when flushing TLB page
  powerpc: defconfigs: add MTD_SPI_NOR (new dependency for M25P80)
  perf/powerpc: reset event hw state when adding it to the PMU
  powerpc/qe: Use strlcpy()
  ...
2015-02-11 18:15:38 -08:00
Laurent Dufour e6eb2eba49 powerpc/xmon: Fix another endiannes issue in RTAS call from xmon
The commit 3b8a3c0109 ("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: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@vger.kernel.org
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-01-19 09:58:16 +11:00
Vincent Bernat 05b981f493 powerpc/xmon: use isspace/isxdigit/isalnum from linux/ctype.h
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: Vincent Bernat <vincent@bernat.im>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-29 15:45:43 +11:00
Linus Torvalds 140cd7fb04 powerpc updates for 3.19
Some nice cleanups like removing bootmem, and removal of __get_cpu_var().
 
 There is one patch to mm/gup.c. This is the generic GUP implementation, but is
 only used by us and arm(64). We have an ack from Steve Capper, and although we
 didn't get an ack from Andrew he told us to take the patch through the powerpc
 tree.
 
 There's one cxl patch. This is in drivers/misc, but Greg said he was happy for
 us to manage fixes for it.
 
 There is an infrastructure patch to support an IPMI driver for OPAL. That patch
 also appears in Corey Minyard's IPMI tree, you may see a conflict there.
 
 There is also an RTC driver for OPAL. We weren't able to get any response from
 the RTC maintainer, Alessandro Zummo, so in the end we just merged the driver.
 
 The usual batch of Freescale updates from Scott.
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Merge tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

Pull powerpc updates from Michael Ellerman:
 "Some nice cleanups like removing bootmem, and removal of
  __get_cpu_var().

  There is one patch to mm/gup.c.  This is the generic GUP
  implementation, but is only used by us and arm(64).  We have an ack
  from Steve Capper, and although we didn't get an ack from Andrew he
  told us to take the patch through the powerpc tree.

  There's one cxl patch.  This is in drivers/misc, but Greg said he was
  happy for us to manage fixes for it.

  There is an infrastructure patch to support an IPMI driver for OPAL.

  There is also an RTC driver for OPAL.  We weren't able to get any
  response from the RTC maintainer, Alessandro Zummo, so in the end we
  just merged the driver.

  The usual batch of Freescale updates from Scott"

* tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits)
  powerpc/powernv: Return to cpu offline loop when finished in KVM guest
  powerpc/book3s: Fix partial invalidation of TLBs in MCE code.
  powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
  powerpc/xmon: Cleanup the breakpoint flags
  powerpc/xmon: Enable HW instruction breakpoint on POWER8
  powerpc/mm/thp: Use tlbiel if possible
  powerpc/mm/thp: Remove code duplication
  powerpc/mm/hugetlb: Sanity check gigantic hugepage count
  powerpc/oprofile: Disable pagefaults during user stack read
  powerpc/mm: Check for matching hpte without taking hpte lock
  powerpc: Drop useless warning in eeh_init()
  powerpc/powernv: Cleanup unused MCE definitions/declarations.
  powerpc/eeh: Dump PHB diag-data early
  powerpc/eeh: Recover EEH error on ownership change for BCM5719
  powerpc/eeh: Set EEH_PE_RESET on PE reset
  powerpc/eeh: Refactor eeh_reset_pe()
  powerpc: Remove more traces of bootmem
  powerpc/pseries: Initialise nvram_pstore_info's buf_lock
  cxl: Name interrupts in /proc/interrupt
  cxl: Return error to PSL if IRQ demultiplexing fails & print clearer warning
  ...
2014-12-11 17:48:14 -08:00
Michael Ellerman abb90ee7bc powerpc/xmon: Cleanup the breakpoint flags
Drop BP_IABR_TE, which though used, does not do anything useful. Rename
BP_IABR to BP_CIABR. Renumber the flags.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-02 14:23:04 +11:00
Anshuman Khandual 1ad7d70562 powerpc/xmon: Enable HW instruction breakpoint on POWER8
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: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
2014-12-02 14:23:04 +11:00
Laurent Dufour 3b8a3c0109 powerpc/pseries: Fix endiannes issue in RTAS call from xmon
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: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-27 09:32:57 +11:00
Michael Ellerman d8ee6f34fd powerpc/xmon: Fix build when 4xx=y and 44x=n
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: Michael Ellerman <mpe@ellerman.id.au>
2014-11-12 16:54:54 +11:00
Alexander Graf 9178ba294b powerpc: Convert power off logic to pm_power_off
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: Alexander Graf <agraf@suse.de>
[mpe: Squash into one patch and update changelog based on cover letter]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-03 12:12:51 +11:00
Anton Blanchard a71d64b4dc powerpc: Hard disable interrupts in xmon
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: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:48 +10:00
Michael Ellerman 13b3d13b81 powerpc: Remove MMU_FTR_SLB
We now only support cpus that use an SLB, so we don't need an MMU
feature to indicate that.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-28 14:10:23 +10:00
Michael Ellerman 376af5947c powerpc: Remove STAB code
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: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-28 14:10:22 +10:00
Michael Ellerman 736256e4f1 powerpc/xmon: Fix up xmon format strings
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: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-05 13:20:00 +10:00
Paul Gortmaker 21f585073d powerpc: Fix smp_processor_id() in preemptible splat in set_breakpoint
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-g2aafe1a4d451 #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: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-20 10:54:06 +10:00
Philippe Bergheaud 72eceef67a powerpc: Fix xmon disassembler for little-endian
This patch fixes the disassembler of the powerpc kernel debugger xmon,
for little-endian.

Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-03-07 15:50:12 +11:00
Michael Ellerman d2b496e5e1 powerpc/xmon: Don't signal we've entered until we're finished printing
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: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-02-11 11:24:51 +11:00
Michael Ellerman 1507589787 powerpc/xmon: Fix timeout loop in get_output_lock()
As far as I can tell, our 70s era timeout loop in get_output_lock() is
generating no code.

This leads to the hostile takeover happening more or less simultaneously
on all cpus. The result is "interesting", some example output that is
more readable than most:

    cpu 0x1: Vector: 100 (Scypsut e0mx bR:e setV)e catto xc0p:u[ c 00
    c0:0  000t0o0V0erc0td:o5 rfc28050000]0c00 0 0  0 6t(pSrycsV1ppuot
    uxe 1m 2 0Rx21e3:0s0ce000c00000t00)00 60602oV2SerucSayt0y 0p 1sxs

Fix it by using udelay() in the timeout loop. The wait time and check
frequency are arbitrary, but seem to work OK. We already rely on
udelay() working so this is not a new dependency.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-02-11 11:24:51 +11:00
Michael Ellerman 730efb6193 powerpc/xmon: Don't loop forever in get_output_lock()
If we enter with xmon_speaker != 0 we skip the first cmpxchg(), we also
skip the while loop because xmon_speaker != last_speaker (0) - meaning we
skip the second cmpxchg() also.

Following that code path the compiler sees no memory barriers and so is
within its rights to never reload xmon_speaker. The end result is we loop
forever.

This manifests as all cpus being in xmon ('c' command), but they refuse
to take control when you switch to them ('c x' for cpu # x).

I have seen this deadlock in practice and also checked the generated code to
confirm this is what's happening.

The simplest fix is just to always try the cmpxchg().

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-02-11 11:24:50 +11:00
Mahesh Salgaonkar 729b0f7153 powerpc/book3s: Introduce exclusive emergency stack for machine check exception.
This patch introduces exclusive emergency stack for machine check exception.
We use emergency stack to handle machine check exception so that we can save
MCE information (srr1, srr0, dar and dsisr) before turning on ME bit and be
ready for re-entrancy. This helps us to prevent clobbering of MCE information
in case of nested machine checks.

The reason for using emergency stack over normal kernel stack is that the
machine check might occur in the middle of setting up a stack frame which may
result into improper use of kernel stack.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-05 16:02:05 +11:00