A strange behaviour is observed when comparing PCI hotplug in QEMU, between
x86 and pseries. If you consider the following steps:
- start a VM
- add a PCI device via the QEMU monitor before the rtasd has started (for
  example starting the VM in paused state, or hotplug during FW or boot
  loader)
- resume the VM execution

The x86 kernel detects the PCI device, but the pseries one does not.

This happens because the rtasd kernel worker is currently started under
device_initcall, while PCI probing happens earlier under subsys_initcall.

As a consequence, if we have a pending RTAS event at boot time, a message
is printed and the event is dropped.

This patch moves all the initialization of rtasd to arch_initcall, which is
run before subsys_call: this way, logging_enabled is true when the RTAS
event pops up and it is not lost anymore.

The proc fs bits stay at device_initcall because they cannot be run before
fs_initcall.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The domain/PHB field of PCI addresses has its value obtained from a
global variable, incremented each time a new domain (represented by
struct pci_controller) is added on the system. The domain addition
process happens during boot or due to PHB hotplug add.

As recent kernels are using predictable naming for network interfaces,
the network stack is more tied to PCI naming. This can be a problem in
hotplug scenarios, because PCI addresses will change if devices are
removed and then re-added. This situation seems unusual, but it can
happen if a user wants to replace a NIC without rebooting the machine,
for example.

This patch changes the way PCI domain values are generated: now, we use
device-tree properties to assign fixed PHB numbers to PCI addresses
when available (meaning pSeries and PowerNV cases). We also use a bitmap
to allow dynamic PHB numbering when device-tree properties are not
used. This bitmap keeps track of used PHB numbers and if a PHB is
released (by hotplug operations for example), it allows the reuse of
this PHB number, avoiding PCI address to change in case of device remove
and re-add soon after. No functional changes were introduced.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
[mpe: Drop unnecessary machine_is(pseries) test]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

Despite attempting to fix this in commit fb36e907 ("powerpc/pci: Fix
SRIOV not building without EEH enabled"), the build is still broken when
PCI_IOV=y and EEH=n (eg. g5_defconfig with PCI_IOV=y):

  arch/powerpc/kernel/pci_dn.c: In function ‘remove_dev_pci_data’:
  arch/powerpc/kernel/pci_dn.c:230:18: error: unused variable ‘edev’

Incorporate Ben's idea of using __maybe_unused to avoid so many #ifdefs.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

For memory hotplug to work, the MMU code needs to provide the functions
create_section_mapping() and remove_section_mapping() to respectively
map and unmap portions of the linear mapping.

At the moment only hash64 provides these, so we provide weak stubs that
just error out. This fixes the build with configurations such as 64-bit
BookE with CONFIG_MEMORY_HOTPLUG enabled.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Use "Delta" to refer to the difference between measurements, rather than
"Error", so scripts that look for "Error" aren't confused into thinking
there was a failure.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds an OPAL console backend to the powerpc boot wrapper so
that decompression failures inside the wrapper can be reported to the
user. This is important since it typically indicates data corruption in
the firmware and other nasty things.

Currently this only works when building a little endian kernel. When
compiling a 64 bit BE kernel the wrapper is always build 32 bit to be
compatible with some 32 bit firmwares. BE support will be added at a
later date. Another limitation of this is that only the "raw" type of
OPAL console is supported, however machines that provide a hvsi console
also provide a raw console so this is not an issue in practice.
Actually-written-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Move #ifdef __powerpc64__ to avoid warnings on 32-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds the kernel command line parameter "no_tb_segs" which
forces the kernel to use 256MB rather than 1TB segments. Forcing the use
of 256MB segments makes it considerably easier to test code that depends
on an SLB miss occurring.
Suggested-by: Michael Neuling <mikey@neuling.org>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Power ISAv3 adds a large decrementer (LD) mode which increases the size
of the decrementer register. The size of the enlarged decrementer
register is between 32 and 64 bits with the exact size being dependent
on the implementation. When in LD mode, reads are sign extended to 64
bits and a decrementer exception is raised when the high bit is set (i.e
the value goes below zero). Writes however are truncated to the physical
register width so some care needs to be taken to ensure that the high
bit is not set when reloading the decrementer. This patch adds support
for using the LD inside the host kernel on processors that support it.

When LD mode is supported firmware will supply the ibm,dec-bits property
for CPU nodes to allow the kernel to determine the maximum decrementer
value. Enabling LD mode is a hypervisor privileged operation so the kernel
can only enable it manually when running in hypervisor mode. Guests that
support LD mode can request it using the "ibm,client-architecture-support"
firmware call (not implemented in this patch) or some other platform
specific method. If this property is not supplied then the traditional
decrementer width of 32 bit is assumed and LD mode will not be enabled.

This patch was based on initial work by Jack Miller.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Check the assembler supports -maltivec by wrapping it with
call as-option.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

cmm_mem_going_offline() is (only) called from cmm_memory_cb(), which
sends the return value through notifier_from_errno(). The latter
expects 0 or -errno (notifier_to_errno(notifier_from_errno(x)) is 0
for any x >= 0, so passing a positive value cannot make sense). Hence
negate ENOMEM.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

If ppc_rtas() is called with args.nargs == 16 and args.nret == 0,
args.rets is set to point to &args.args[16], which is beyond the end of
the args.args array. This results in a minor read overrun of the array
when we check the first return code (which, per PAPR, is a required
output of all RTAS calls) to see if there's been a hardware error.

Change the nargs/nret check to ensure nargs is <= 15, allowing room for
the status code. Users shouldn't be calling with nret == 0, but there's
no real harm if they do, so we don't stop them.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Test that an ISA 3.0 compliant machine performing an unaligned copy,
copy_first, paste or paste_last is sent a SIGBUS.
Signed-off-by: Chris Smart <chris@distroguy.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Calling ISA 3.0 instructions copy, copy_first, paste and paste_last
generates an alignment fault when copying or pasting unaligned
data (128 byte). We catch this and send SIGBUS to the userspace
process that caused it.

We do not emulate these because paste may contain additional metadata
when pasting to a co-processor and paste_last is the synchronisation
point for preceding copy/paste sequences.

Thanks to Michael Neuling <mikey@neuling.org> for his help.
Signed-off-by: Chris Smart <chris@distroguy.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These are useful little loops for smoke testing performance.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently it doesn't appear the resulting binary actually uses any
Altivec or VSX instructions the solution is to explicitly tell GCC to
use vector instructions and use vector types in the code.

Part of this this issue can be GCC version specific:

GCC 4.9.x is happy to use Altivec and VSX instructions if altivec.h is
includedi (and possibly if vector types are used), this also means that
4.9.x will use VSX instructions even if only -maltivec is passed. It is
also possible that Altivec instructions will be used even without
-maltivec or -mabi=altivec.

GCC 5.2.x complains about the lack of -maltivec parameter if altivec.h
is included and will not use VSX unless -mvsx is present on commandline.

GCC 5.3.0 has a regression that means __attribute__((__target__("no-vsx"))
fails to build. A fix is targeted for 5.4.

Furthermore LTO (Link Time Optimisation) doesn't play well with
__attribute__((__target__("no-vsx")), LTO can cause GCC to forget about
the attribute and compile with VSX instructions regardless. Be wary when
enabling -flfo for this test.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When we inverted the behaviour of the flags we forgot to update the
usage message.

Fixes: 51c21e72 ("selftests/powerpc: Make context_switch touch FP/altivec/vector by default")
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Excerpt from man 2 perf_event_open:

  /proc/sys/kernel/perf_event_paranoid
  The perf_event_paranoid file can be set to restrict access to the
  performance counters.
    2 allow only user-space measurements.
    1 allow both kernel and user measurements (default).
    0 allow access to CPU-specific data but not raw tracepoint samples.
   -1 no restrictions.

require_paranoia_below() should return 0 if perf_event_paranoid is below
a specified level, the value from perf_event_paranoid is read into an
unsigned long so the incorrect value is returned when
perf_event_paranoid is set to -1.

Without this patch applied there is the same number of selftests/powerpc
which skip when /proc/sys/kernel/perf_event_paranoid is set to 1 or -1
but no skips when set to zero.

With this patch applied there are no skipped selftests/powerpc test when
/proc/sys/kernel/perf_event_paranoid is set to 0 or -1.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Export the generic hardware and cache perf events for Power9 to sysfs,
so users can determine the PMU event monitored.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds base enablement for the power9 PMU.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add macros for the generic and cache events on Power9
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Factor out the power8 pmu init functions to share with
power9. Monitor Mode Control Register S(MMCRS) and
Monitor Mode Control Register H(MMCRH) registers are
dropped in Power9. These registers are added to new
function which are included for power8 init.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Factor out some of the power8 pmu functions
to new file "isa207-common.c" to share with
power9 pmu code. Only code movement and no
logic change
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Factor out some of the power8 pmu macros to
new a header file to share with power9 pmu code.
Just code movement and no logic change.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We spent so much time bike-shedding the printk() we missed that the next
line was missing a semi-colon. And it seems none of our defconfigs turn
on CONFIG_FA_DUMP.

Fixes: 4a03749f ("powerpc/fadump: Trivial fix of spelling mistake, clean up message")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Implement new character device driver to allow access from user space
to the operator panel display present on IBM Power Systems machines
with FSPs.

This will allow status information to be presented on the display which
is visible to a user.

The driver implements a character buffer which a user can read/write
by accessing the device (/dev/op_panel). This buffer is then displayed on
the operator panel display. Any attempt to write past the last character
position will have no effect and attempts to write more characters than
the size of the display will be truncated. The device may only be accessed
by a single process at a time.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

An opal_msg of type OPAL_MSG_ASYNC_COMP contains the return code in the
params[1] struct member. However this isn't intuitive or obvious when
reading the code and requires that a user look at the skiboot
documentation or opal-api.h to verify this.

Add an inline function to get the return code from an opal_msg and update
call sites accordingly.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add a binding to Documentation/devicetree/bindings/powerpc/opal
(oppanel-opal.txt) for the operator panel which is present on IBM
Power Systems machines with FSPs.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This provides AFU drivers a means to associate private data with a cxl
context. This is particularly intended for make the new callbacks for
driver specific events easier for AFU drivers to use, as they can easily
get back to any private data structures they may use.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com
Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This adds an afu_driver_ops structure with fetch_event() and
event_delivered() callbacks. An AFU driver such as cxlflash can fill
this out and associate it with a context to enable passing custom AFU
specific events to userspace.

This also adds a new kernel API function cxl_context_pending_events(),
that the AFU driver can use to notify the cxl driver that new specific
events are ready to be delivered, and wake up anyone waiting on the
context wait queue.

The current count of AFU driver specific events is stored in the field
afu_driver_events of the context structure.

The cxl driver checks the afu_driver_events count during poll, select,
read, etc. calls to check if an AFU driver specific event is pending,
and calls fetch_event() to obtain and deliver that event. This way, the
cxl driver takes care of all the usual locking semantics around these
calls and handles all the generic cxl events, so that the AFU driver
only needs to worry about it's own events.

fetch_event() return a struct cxl_event_afu_driver_reserved, allocated
by the AFU driver, and filled in with the specific event information and
size. Total event size (header + data) should not be greater than
CXL_READ_MIN_SIZE (4K).

Th cxl driver prepends an appropriate cxl event header, copies the event
to userspace, and finally calls event_delivered() to return the status of
the operation to the AFU driver. The event is identified by the context
and cxl_event_afu_driver_reserved pointers.

Since AFU drivers provide their own means for userspace to obtain the
AFU file descriptor (i.e. cxlflash uses an ioctl on their scsi file
descriptor to obtain the AFU file descriptor) and the generic cxl driver
will never use this event, the ABI of the event is up to each individual
AFU driver.
Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Trivial fix to spelling mistake in pr_debug() message.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Fix trivial spelling mistake "rgistration". Also use pr_err()
instead of printk() and unsplit the string to keep it all on one
line.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
[mpe: Keep rc on the same line, splitting it doesn't help]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

If a PHB has no I/O space, there's no need to make it look like
something bad happened, a pr_debug() is plenty enough since this
is the case of all our modern POWER chips.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

PPC64 eBPF JIT compiler.

Enable with:
  echo 1 > /proc/sys/net/core/bpf_jit_enable
or
  echo 2 > /proc/sys/net/core/bpf_jit_enable

... to see the generated JIT code. This can further be processed with
tools/net/bpf_jit_disasm.

With CONFIG_TEST_BPF=m and 'modprobe test_bpf':

 test_bpf: Summary: 305 PASSED, 0 FAILED, [297/297 JIT'ed]

... on both ppc64 BE and LE.

The details of the approach are documented through various comments in
the code.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Break out classic BPF JIT specifics into a separate header in
preparation for eBPF JIT implementation. Note that ppc32 will still need
the classic BPF JIT.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1. Per the ISA, ADDIS actually uses RT, rather than RS. Though
   the result is the same, make the usage clear.
2. The multiply instruction used is a 32-bit multiply. Rename PPC_MUL()
   to PPC_MULW() to make the same clear.
3. PPC_STW[U] take the entire 16-bit immediate value and do not require
   word-alignment, per the ISA. Change the macros to use IMM_L().
4. A few white-space cleanups to satisfy checkpatch.pl.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Since we will be using the rotate immediate instructions for extended
BPF JIT, let's introduce macros for the same. And since the shift
immediate operations use the rotate immediate instructions, let's redo
those macros to use the newly introduced instructions.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Similar to the LI32() optimization, if the value can be represented
in 32-bits, use LI32(). Also handle loading a few specific forms of
immediate values in an optimum manner.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The existing LI32() macro can sometimes result in a sign-extended 32-bit
load that does not clear the top 32-bits properly. As an example,
loading 0x7fffffff results in the register containing
0xffffffff7fffffff. While this does not impact classic BPF JIT
implementation (since that only uses the lower word for all operations),
we would like to share this macro between classic BPF JIT and extended
BPF JIT, wherein the entire 64-bit value in the register matters. Fix
this by first doing a shifted LI followed by ORI.

An additional optimization is with loading values between -32768 to -1,
where we now only need a single LI.

The new implementation now generates the same or less number of
instructions.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>