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Pull powerpc merge from Benjamin Herrenschmidt:
 "Here's the powerpc batch for this merge window.  It is going to be a
  bit more nasty than usual as in touching things outside of
  arch/powerpc mostly due to the big iSeriesectomy :-) We finally got
  rid of the bugger (legacy iSeries support) which was a PITA to
  maintain and that nobody really used anymore.

  Here are some of the highlights:

   - Legacy iSeries is gone.  Thanks Stephen ! There's still some bits
     and pieces remaining if you do a grep -ir series arch/powerpc but
     they are harmless and will be removed in the next few weeks
     hopefully.

   - The 'fadump' functionality (Firmware Assisted Dump) replaces the
     previous (equivalent) "pHyp assisted dump"...  it's a rewrite of a
     mechanism to get the hypervisor to do crash dumps on pSeries, the
     new implementation hopefully being much more reliable.  Thanks
     Mahesh Salgaonkar.

   - The "EEH" code (pSeries PCI error handling & recovery) got a big
     spring cleaning, motivated by the need to be able to implement a
     new backend for it on top of some new different type of firwmare.

     The work isn't complete yet, but a good chunk of the cleanups is
     there.  Note that this adds a field to struct device_node which is
     not very nice and which Grant objects to.  I will have a patch soon
     that moves that to a powerpc private data structure (hopefully
     before rc1) and we'll improve things further later on (hopefully
     getting rid of the need for that pointer completely).  Thanks Gavin
     Shan.

   - I dug into our exception & interrupt handling code to improve the
     way we do lazy interrupt handling (and make it work properly with
     "edge" triggered interrupt sources), and while at it found & fixed
     a wagon of issues in those areas, including adding support for page
     fault retry & fatal signals on page faults.

   - Your usual random batch of small fixes & updates, including a bunch
     of new embedded boards, both Freescale and APM based ones, etc..."

I fixed up some conflicts with the generalized irq-domain changes from
Grant Likely, hopefully correctly.

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (141 commits)
  powerpc/ps3: Do not adjust the wrapper load address
  powerpc: Remove the rest of the legacy iSeries include files
  powerpc: Remove the remaining CONFIG_PPC_ISERIES pieces
  init: Remove CONFIG_PPC_ISERIES
  powerpc: Remove FW_FEATURE ISERIES from arch code
  tty/hvc_vio: FW_FEATURE_ISERIES is no longer selectable
  powerpc/spufs: Fix double unlocks
  powerpc/5200: convert mpc5200 to use of_platform_populate()
  powerpc/mpc5200: add options to mpc5200_defconfig
  powerpc/mpc52xx: add a4m072 board support
  powerpc/mpc5200: update mpc5200_defconfig to fit for charon board
  Documentation/powerpc/mpc52xx.txt: Checkpatch cleanup
  powerpc/44x: Add additional device support for APM821xx SoC and Bluestone board
  powerpc/44x: Add support PCI-E for APM821xx SoC and Bluestone board
  MAINTAINERS: Update PowerPC 4xx tree
  powerpc/44x: The bug fixed support for APM821xx SoC and Bluestone board
  powerpc: document the FSL MPIC message register binding
  powerpc: add support for MPIC message register API
  powerpc/fsl: Added aliased MSIIR register address to MSI node in dts
  powerpc/85xx: mpc8548cds - add 36-bit dts
  ...
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2 parents b57cb72 + dfbc2d7 commit 5375871
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63 changes: 63 additions & 0 deletions Documentation/devicetree/bindings/powerpc/fsl/mpic-msgr.txt
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* FSL MPIC Message Registers

This binding specifies what properties must be available in the device tree
representation of the message register blocks found in some FSL MPIC
implementations.

Required properties:

- compatible: Specifies the compatibility list for the message register
block. The type shall be <string-list> and the value shall be of the form
"fsl,mpic-v<version>-msgr", where <version> is the version number of
the MPIC containing the message registers.

- reg: Specifies the base physical address(s) and size(s) of the
message register block's addressable register space. The type shall be
<prop-encoded-array>.

- interrupts: Specifies a list of interrupt-specifiers which are available
for receiving interrupts. Interrupt-specifier consists of two cells: first
cell is interrupt-number and second cell is level-sense. The type shall be
<prop-encoded-array>.

Optional properties:

- mpic-msgr-receive-mask: Specifies what registers in the containing block
are allowed to receive interrupts. The value is a bit mask where a set
bit at bit 'n' indicates that message register 'n' can receive interrupts.
Note that "bit 'n'" is numbered from LSB for PPC hardware. The type shall
be <u32>. If not present, then all of the message registers in the block
are available.

Aliases:

An alias should be created for every message register block. They are not
required, though. However, a particular implementation of this binding
may require aliases to be present. Aliases are of the form
'mpic-msgr-block<n>', where <n> is an integer specifying the block's number.
Numbers shall start at 0.

Example:

aliases {
mpic-msgr-block0 = &mpic_msgr_block0;
mpic-msgr-block1 = &mpic_msgr_block1;
};

mpic_msgr_block0: mpic-msgr-block@41400 {
compatible = "fsl,mpic-v3.1-msgr";
reg = <0x41400 0x200>;
// Message registers 0 and 2 in this block can receive interrupts on
// sources 0xb0 and 0xb2, respectively.
interrupts = <0xb0 2 0xb2 2>;
mpic-msgr-receive-mask = <0x5>;
};

mpic_msgr_block1: mpic-msgr-block@42400 {
compatible = "fsl,mpic-v3.1-msgr";
reg = <0x42400 0x200>;
// Message registers 0 and 2 in this block can receive interrupts on
// sources 0xb4 and 0xb6, respectively.
interrupts = <0xb4 2 0xb6 2>;
mpic-msgr-receive-mask = <0x5>;
};
22 changes: 21 additions & 1 deletion Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
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Expand Up @@ -56,7 +56,27 @@ PROPERTIES
to the client. The presence of this property also mandates
that any initialization related to interrupt sources shall
be limited to sources explicitly referenced in the device tree.


- big-endian
Usage: optional
Value type: <empty>
If present the MPIC will be assumed to be big-endian. Some
device-trees omit this property on MPIC nodes even when the MPIC is
in fact big-endian, so certain boards override this property.

- single-cpu-affinity
Usage: optional
Value type: <empty>
If present the MPIC will be assumed to only be able to route
non-IPI interrupts to a single CPU at a time (EG: Freescale MPIC).

- last-interrupt-source
Usage: optional
Value type: <u32>
Some MPICs do not correctly report the number of hardware sources
in the global feature registers. If specified, this field will
override the value read from MPIC_GREG_FEATURE_LAST_SRC.

INTERRUPT SPECIFIER DEFINITION

Interrupt specifiers consists of 4 cells encoded as
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6 changes: 4 additions & 2 deletions Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt
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Expand Up @@ -6,8 +6,10 @@ Required properties:
etc.) and the second is "fsl,mpic-msi" or "fsl,ipic-msi" depending on
the parent type.

- reg : should contain the address and the length of the shared message
interrupt register set.
- reg : It may contain one or two regions. The first region should contain
the address and the length of the shared message interrupt register set.
The second region should contain the address of aliased MSIIR register for
platforms that have such an alias.

- msi-available-ranges: use <start count> style section to define which
msi interrupt can be used in the 256 msi interrupts. This property is
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270 changes: 270 additions & 0 deletions Documentation/powerpc/firmware-assisted-dump.txt
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Firmware-Assisted Dump
------------------------
July 2011

The goal of firmware-assisted dump is to enable the dump of
a crashed system, and to do so from a fully-reset system, and
to minimize the total elapsed time until the system is back
in production use.

- Firmware assisted dump (fadump) infrastructure is intended to replace
the existing phyp assisted dump.
- Fadump uses the same firmware interfaces and memory reservation model
as phyp assisted dump.
- Unlike phyp dump, fadump exports the memory dump through /proc/vmcore
in the ELF format in the same way as kdump. This helps us reuse the
kdump infrastructure for dump capture and filtering.
- Unlike phyp dump, userspace tool does not need to refer any sysfs
interface while reading /proc/vmcore.
- Unlike phyp dump, fadump allows user to release all the memory reserved
for dump, with a single operation of echo 1 > /sys/kernel/fadump_release_mem.
- Once enabled through kernel boot parameter, fadump can be
started/stopped through /sys/kernel/fadump_registered interface (see
sysfs files section below) and can be easily integrated with kdump
service start/stop init scripts.

Comparing with kdump or other strategies, firmware-assisted
dump offers several strong, practical advantages:

-- Unlike kdump, the system has been reset, and loaded
with a fresh copy of the kernel. In particular,
PCI and I/O devices have been reinitialized and are
in a clean, consistent state.
-- Once the dump is copied out, the memory that held the dump
is immediately available to the running kernel. And therefore,
unlike kdump, fadump doesn't need a 2nd reboot to get back
the system to the production configuration.

The above can only be accomplished by coordination with,
and assistance from the Power firmware. The procedure is
as follows:

-- The first kernel registers the sections of memory with the
Power firmware for dump preservation during OS initialization.
These registered sections of memory are reserved by the first
kernel during early boot.

-- When a system crashes, the Power firmware will save
the low memory (boot memory of size larger of 5% of system RAM
or 256MB) of RAM to the previous registered region. It will
also save system registers, and hardware PTE's.

NOTE: The term 'boot memory' means size of the low memory chunk
that is required for a kernel to boot successfully when
booted with restricted memory. By default, the boot memory
size will be the larger of 5% of system RAM or 256MB.
Alternatively, user can also specify boot memory size
through boot parameter 'fadump_reserve_mem=' which will
override the default calculated size. Use this option
if default boot memory size is not sufficient for second
kernel to boot successfully.

-- After the low memory (boot memory) area has been saved, the
firmware will reset PCI and other hardware state. It will
*not* clear the RAM. It will then launch the bootloader, as
normal.

-- The freshly booted kernel will notice that there is a new
node (ibm,dump-kernel) in the device tree, indicating that
there is crash data available from a previous boot. During
the early boot OS will reserve rest of the memory above
boot memory size effectively booting with restricted memory
size. This will make sure that the second kernel will not
touch any of the dump memory area.

-- User-space tools will read /proc/vmcore to obtain the contents
of memory, which holds the previous crashed kernel dump in ELF
format. The userspace tools may copy this info to disk, or
network, nas, san, iscsi, etc. as desired.

-- Once the userspace tool is done saving dump, it will echo
'1' to /sys/kernel/fadump_release_mem to release the reserved
memory back to general use, except the memory required for
next firmware-assisted dump registration.

e.g.
# echo 1 > /sys/kernel/fadump_release_mem

Please note that the firmware-assisted dump feature
is only available on Power6 and above systems with recent
firmware versions.

Implementation details:
----------------------

During boot, a check is made to see if firmware supports
this feature on that particular machine. If it does, then
we check to see if an active dump is waiting for us. If yes
then everything but boot memory size of RAM is reserved during
early boot (See Fig. 2). This area is released once we finish
collecting the dump from user land scripts (e.g. kdump scripts)
that are run. If there is dump data, then the
/sys/kernel/fadump_release_mem file is created, and the reserved
memory is held.

If there is no waiting dump data, then only the memory required
to hold CPU state, HPTE region, boot memory dump and elfcore
header, is reserved at the top of memory (see Fig. 1). This area
is *not* released: this region will be kept permanently reserved,
so that it can act as a receptacle for a copy of the boot memory
content in addition to CPU state and HPTE region, in the case a
crash does occur.

o Memory Reservation during first kernel

Low memory Top of memory
0 boot memory size |
| | |<--Reserved dump area -->|
V V | Permanent Reservation V
+-----------+----------/ /----------+---+----+-----------+----+
| | |CPU|HPTE| DUMP |ELF |
+-----------+----------/ /----------+---+----+-----------+----+
| ^
| |
\ /
-------------------------------------------
Boot memory content gets transferred to
reserved area by firmware at the time of
crash
Fig. 1

o Memory Reservation during second kernel after crash

Low memory Top of memory
0 boot memory size |
| |<------------- Reserved dump area ----------- -->|
V V V
+-----------+----------/ /----------+---+----+-----------+----+
| | |CPU|HPTE| DUMP |ELF |
+-----------+----------/ /----------+---+----+-----------+----+
| |
V V
Used by second /proc/vmcore
kernel to boot
Fig. 2

Currently the dump will be copied from /proc/vmcore to a
a new file upon user intervention. The dump data available through
/proc/vmcore will be in ELF format. Hence the existing kdump
infrastructure (kdump scripts) to save the dump works fine with
minor modifications.

The tools to examine the dump will be same as the ones
used for kdump.

How to enable firmware-assisted dump (fadump):
-------------------------------------

1. Set config option CONFIG_FA_DUMP=y and build kernel.
2. Boot into linux kernel with 'fadump=on' kernel cmdline option.
3. Optionally, user can also set 'fadump_reserve_mem=' kernel cmdline
to specify size of the memory to reserve for boot memory dump
preservation.

NOTE: If firmware-assisted dump fails to reserve memory then it will
fallback to existing kdump mechanism if 'crashkernel=' option
is set at kernel cmdline.

Sysfs/debugfs files:
------------

Firmware-assisted dump feature uses sysfs file system to hold
the control files and debugfs file to display memory reserved region.

Here is the list of files under kernel sysfs:

/sys/kernel/fadump_enabled

This is used to display the fadump status.
0 = fadump is disabled
1 = fadump is enabled

This interface can be used by kdump init scripts to identify if
fadump is enabled in the kernel and act accordingly.

/sys/kernel/fadump_registered

This is used to display the fadump registration status as well
as to control (start/stop) the fadump registration.
0 = fadump is not registered.
1 = fadump is registered and ready to handle system crash.

To register fadump echo 1 > /sys/kernel/fadump_registered and
echo 0 > /sys/kernel/fadump_registered for un-register and stop the
fadump. Once the fadump is un-registered, the system crash will not
be handled and vmcore will not be captured. This interface can be
easily integrated with kdump service start/stop.

/sys/kernel/fadump_release_mem

This file is available only when fadump is active during
second kernel. This is used to release the reserved memory
region that are held for saving crash dump. To release the
reserved memory echo 1 to it:

echo 1 > /sys/kernel/fadump_release_mem

After echo 1, the content of the /sys/kernel/debug/powerpc/fadump_region
file will change to reflect the new memory reservations.

The existing userspace tools (kdump infrastructure) can be easily
enhanced to use this interface to release the memory reserved for
dump and continue without 2nd reboot.

Here is the list of files under powerpc debugfs:
(Assuming debugfs is mounted on /sys/kernel/debug directory.)

/sys/kernel/debug/powerpc/fadump_region

This file shows the reserved memory regions if fadump is
enabled otherwise this file is empty. The output format
is:
<region>: [<start>-<end>] <reserved-size> bytes, Dumped: <dump-size>

e.g.
Contents when fadump is registered during first kernel

# cat /sys/kernel/debug/powerpc/fadump_region
CPU : [0x0000006ffb0000-0x0000006fff001f] 0x40020 bytes, Dumped: 0x0
HPTE: [0x0000006fff0020-0x0000006fff101f] 0x1000 bytes, Dumped: 0x0
DUMP: [0x0000006fff1020-0x0000007fff101f] 0x10000000 bytes, Dumped: 0x0

Contents when fadump is active during second kernel

# cat /sys/kernel/debug/powerpc/fadump_region
CPU : [0x0000006ffb0000-0x0000006fff001f] 0x40020 bytes, Dumped: 0x40020
HPTE: [0x0000006fff0020-0x0000006fff101f] 0x1000 bytes, Dumped: 0x1000
DUMP: [0x0000006fff1020-0x0000007fff101f] 0x10000000 bytes, Dumped: 0x10000000
: [0x00000010000000-0x0000006ffaffff] 0x5ffb0000 bytes, Dumped: 0x5ffb0000

NOTE: Please refer to Documentation/filesystems/debugfs.txt on
how to mount the debugfs filesystem.


TODO:
-----
o Need to come up with the better approach to find out more
accurate boot memory size that is required for a kernel to
boot successfully when booted with restricted memory.
o The fadump implementation introduces a fadump crash info structure
in the scratch area before the ELF core header. The idea of introducing
this structure is to pass some important crash info data to the second
kernel which will help second kernel to populate ELF core header with
correct data before it gets exported through /proc/vmcore. The current
design implementation does not address a possibility of introducing
additional fields (in future) to this structure without affecting
compatibility. Need to come up with the better approach to address this.
The possible approaches are:
1. Introduce version field for version tracking, bump up the version
whenever a new field is added to the structure in future. The version
field can be used to find out what fields are valid for the current
version of the structure.
2. Reserve the area of predefined size (say PAGE_SIZE) for this
structure and have unused area as reserved (initialized to zero)
for future field additions.
The advantage of approach 1 over 2 is we don't need to reserve extra space.
---
Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
This document is based on the original documentation written for phyp
assisted dump by Linas Vepstas and Manish Ahuja.
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