Currently, when going idle, we set the flag indicating that we are in
nap mode (paca->kvm_hstate.hwthread_state) and then execute the nap
(or sleep or rvwinkle) instruction, all with the MMU on.  This is bad
for two reasons: (a) the architecture specifies that those instructions
must be executed with the MMU off, and in fact with only the SF, HV, ME
and possibly RI bits set, and (b) this introduces a race, because as
soon as we set the flag, another thread can switch the MMU to a guest
context.  If the race is lost, this thread will typically start looping
on relocation-on ISIs at 0xc...4400.

This fixes it by setting the MSR as required by the architecture before
setting the flag or executing the nap/sleep/rvwinkle instruction.

Cc: stable@vger.kernel.org
[ shreyas@linux.vnet.ibm.com: Edited to handle LE ]
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Michael points out that __get_SP() is a pretty horrible
function name. Let's give it a better name.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Li Zhong points out an issue with our current __get_SP()
implementation. If ftrace function tracing is enabled (ie -pg
profiling using _mcount) we spill a stack frame on 64bit all the
time.

If a function calls __get_SP() and later calls a function that is
tail call optimised, we will pop the stack frame and the value
returned by __get_SP() is no longer valid. An example from Li can
be found in save_stack_trace -> save_context_stack:

c0000000000432c0 <.save_stack_trace>:
c0000000000432c0:       mflr    r0
c0000000000432c4:       std     r0,16(r1)
c0000000000432c8:       stdu    r1,-128(r1) <-- stack frame for _mcount
c0000000000432cc:       std     r3,112(r1)
c0000000000432d0:       bl      <._mcount>
c0000000000432d4:       nop

c0000000000432d8:       mr      r4,r1 <-- __get_SP()

c0000000000432dc:       ld      r5,632(r13)
c0000000000432e0:       ld      r3,112(r1)
c0000000000432e4:       li      r6,1

c0000000000432e8:       addi    r1,r1,128 <-- pop stack frame

c0000000000432ec:       ld      r0,16(r1)
c0000000000432f0:       mtlr    r0
c0000000000432f4:       b       <.save_context_stack> <-- tail call optimized

save_context_stack ends up with a stack pointer below the current
one, and it is likely to be scribbled over.

Fix this by making __get_SP() a function which returns the
callers stack frame. Also replace inline assembly which grabs
the stack pointer in save_stack_trace and show_stack with
__get_SP().

This also fixes an issue with perf_arch_fetch_caller_regs().
It currently unwinds the stack once, which will skip a
valid stack frame on a leaf function. With the __get_SP() fixes
in this patch, we never need to unwind the stack frame to get
to the first interesting frame.

We have to export __get_SP() because perf_arch_fetch_caller_regs()
(which is used in modules) calls it from a header file.
Reported-by: NLi Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Since commit 469d62be, SPRG2 is used as a
scratch register just like SPRG0 and SPRG1. So Declare it as such and fix
the comment which is not valid anymore since that commit.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NScott Wood <scottwood@freescale.com>

It appears that commits 7f06f21d ("powerpc/tm: Add checking to
treclaim/trechkpt") and e4e38121 ("KVM: PPC: Book3S HV: Add
transactional memory support") both added definitions of TEXASR_FS.
Remove one of them. At the same time, fix the alignment of the remaining
definition (should be tab-separated like the rest of the #defines).
Signed-off-by: NNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The POWER8 processor has a Micro Partition Prefetch Engine, which is
a fancy way of saying "has way to store and load contents of L2 or
L2+MRU way of L3 cache". We initiate the storing of the log (list of
addresses) using the logmpp instruction and start restore by writing
to a SPR.

The logmpp instruction takes parameters in a single 64bit register:
- starting address of the table to store log of L2/L2+L3 cache contents
  - 32kb for L2
  - 128kb for L2+L3
  - Aligned relative to maximum size of the table (32kb or 128kb)
- Log control (no-op, L2 only, L2 and L3, abort logout)

We should abort any ongoing logging before initiating one.

To initiate restore, we write to the MPPR SPR. The format of what to write
to the SPR is similar to the logmpp instruction parameter:
- starting address of the table to read from (same alignment requirements)
- table size (no data, until end of table)
- prefetch rate (from fastest possible to slower. about every 8, 16, 24 or
  32 cycles)

The idea behind loading and storing the contents of L2/L3 cache is to
reduce memory latency in a system that is frequently swapping vcores on
a physical CPU.

The best case scenario for doing this is when some vcores are doing very
cache heavy workloads. The worst case is when they have about 0 cache hits,
so we just generate needless memory operations.

This implementation just does L2 store/load. In my benchmarks this proves
to be useful.

Benchmark 1:
 - 16 core POWER8
 - 3x Ubuntu 14.04LTS guests (LE) with 8 VCPUs each
 - No split core/SMT
 - two guests running sysbench memory test.
   sysbench --test=memory --num-threads=8 run
 - one guest running apache bench (of default HTML page)
   ab -n 490000 -c 400 http://localhost/

This benchmark aims to measure performance of real world application (apache)
where other guests are cache hot with their own workloads. The sysbench memory
benchmark does pointer sized writes to a (small) memory buffer in a loop.

In this benchmark with this patch I can see an improvement both in requests
per second (~5%) and in mean and median response times (again, about 5%).
The spread of minimum and maximum response times were largely unchanged.

benchmark 2:
 - Same VM config as benchmark 1
 - all three guests running sysbench memory benchmark

This benchmark aims to see if there is a positive or negative affect to this
cache heavy benchmark. Although due to the nature of the benchmark (stores) we
may not see a difference in performance, but rather hopefully an improvement
in consistency of performance (when vcore switched in, don't have to wait
many times for cachelines to be pulled in)

The results of this benchmark are improvements in consistency of performance
rather than performance itself. With this patch, the few outliers in duration
go away and we get more consistent performance in each guest.

benchmark 3:
 - same 3 guests and CPU configuration as benchmark 1 and 2.
 - two idle guests
 - 1 guest running STREAM benchmark

This scenario also saw performance improvement with this patch. On Copy and
Scale workloads from STREAM, I got 5-6% improvement with this patch. For
Add and triad, it was around 10% (or more).

benchmark 4:
 - same 3 guests as previous benchmarks
 - two guests running sysbench --memory, distinctly different cache heavy
   workload
 - one guest running STREAM benchmark.

Similar improvements to benchmark 3.

benchmark 5:
 - 1 guest, 8 VCPUs, Ubuntu 14.04
 - Host configured with split core (SMT8, subcores-per-core=4)
 - STREAM benchmark

In this benchmark, we see a 10-20% performance improvement across the board
of STREAM benchmark results with this patch.

Based on preliminary investigation and microbenchmarks
by Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: NStewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Scott Wood pointed out that We are no longer using SPRG1 for vcpu pointer,
but using SPRN_SPRG_THREAD <=> SPRG3 (thread->vcpu). So this comment
is not valid now.

Note: SPRN_SPRG3R is not supported (do not see any need as of now),
and if we want to support this in future then we have to shift to using
SPRG1 for VCPU pointer.
Signed-off-by: NBharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

virtual time base register is a per VM, per cpu register that needs
to be saved and restored on vm exit and entry. Writing to VTB is not
allowed in the privileged mode.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: fix compile error]
Signed-off-by: NAlexander Graf <agraf@suse.de>

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>

This adds workarounds for two hardware bugs in the POWER8 performance
monitor unit (PMU), both related to interrupt generation.  The effect
of these bugs is that PMU interrupts can get lost, leading to tools
such as perf reporting fewer counts and samples than they should.

The first bug relates to the PMAO (perf. mon. alert occurred) bit in
MMCR0; setting it should cause an interrupt, but doesn't.  The other
bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0.
Setting PMAE when a counter is negative and counter negative
conditions are enabled to cause alerts should cause an alert, but
doesn't.

The workaround for the first bug is to create conditions where a
counter will overflow, whenever we are about to restore a MMCR0
value that has PMAO set (and PMAO_SYNC clear).  The workaround for
the second bug is to freeze all counters using MMCR2 before reading
MMCR0.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Upcoming POWER8 chips support a concept called split core. This is where the
core can be split into subcores that although not full cores, are able to
appear as full cores to a guest.

The splitting & unsplitting procedure is mildly complicated, and explained at
length in the comments within the patch.

One notable detail is that when splitting or unsplitting we need to pull
offline cpus out of their offline state to do work as part of the procedure.

The interface for changing the split mode is via a sysfs file, eg:

 $ echo 2 > /sys/devices/system/cpu/subcores_per_core

Currently supported values are '1', '2' and '4'. And indicate respectively that
the core should be unsplit, split in half, and split in quarters. These modes
correspond to threads_per_subcore of 8, 4 and 2.

We do not allow changing the split mode while KVM VMs are active. This is to
prevent the value changing while userspace is configuring the VM, and also to
prevent the mode being changed in such a way that existing guests are unable to
be run.

CPU hotplug fixes by Srivatsa.  max_cpus fixes by Mahesh.  cpuset fixes by
benh.  Fix for irq race by paulus.  The rest by mikey and mpe.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If we do a treclaim and we are not in TM suspend mode, it results in a TM bad
thing (ie. a 0x700 program check).  Similarly if we do a trechkpt and we have
an active transaction or TEXASR Failure Summary (FS) is not set, we also take a
TM bad thing.

This should never happen, but if it does (ie. a kernel bug), the cause is
almost impossible to debug as the GPR state is mostly userspace and hence we
don't get a call chain.

This adds some checks in these cases case a BUG_ON() (in asm) in case we ever
hit these cases.  It moves the register saving around to preserve r1 till later
also.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Backend driver to dynamically set voltage and frequency on
IBM POWER non-virtualized platforms.  Power management SPRs
are used to set the required PState.

This driver works in conjunction with cpufreq governors
like 'ondemand' to provide a demand based frequency and
voltage setting on IBM POWER non-virtualized platforms.

PState table is obtained from OPAL v3 firmware through device
tree.

powernv_cpufreq back-end driver would parse the relevant device-tree
nodes and initialise the cpufreq subsystem on powernv platform.

The code was originally written by svaidy@linux.vnet.ibm.com. Over
time it was modified to accomodate bug-fixes as well as updates to the
the cpu-freq core. Relevant portions of the change logs corresponding
to those modifications are noted below:

 * The policy->cpus needs to be populated in a hotplug-invariant
   manner instead of using cpu_sibling_mask() which varies with
   cpu-hotplug. This is because the cpufreq core code copies this
   content into policy->related_cpus mask which should not vary on
   cpu-hotplug. [Authored by srivatsa.bhat@linux.vnet.ibm.com]

 * Create a helper routine that can return the cpu-frequency for the
   corresponding pstate_id. Also, cache the values of the pstate_max,
   pstate_min and pstate_nominal and nr_pstates in a static structure
   so that they can be reused in the future to perform any
   validations. [Authored by ego@linux.vnet.ibm.com]

 * Create a driver attribute named cpuinfo_nominal_freq which creates
   a sysfs read-only file named cpuinfo_nominal_freq. Export the
   frequency corresponding to the nominal_pstate through this
   interface.

     Nominal frequency is the highest non-turbo frequency for the
   platform.  This is generally used for setting governor policies
   from user space for optimal energy efficiency. [Authored by
   ego@linux.vnet.ibm.com]

 * Implement a powernv_cpufreq_get(unsigned int cpu) method which will
   return the current operating frequency. Export this via the sysfs
   interface cpuinfo_cur_freq by setting powernv_cpufreq_driver.get to
   powernv_cpufreq_get(). [Authored by ego@linux.vnet.ibm.com]

[Change log updated by ego@linux.vnet.ibm.com]
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NGautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This adds saving of the transactional memory (TM) checkpointed state
on guest entry and exit.  We only do this if we see that the guest has
an active transaction.

It also adds emulation of the TM state changes when delivering IRQs
into the guest.  According to the architecture, if we are
transactional when an IRQ occurs, the TM state is changed to
suspended, otherwise it's left unchanged.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NScott Wood <scottwood@freescale.com>

The previous commit added constraint and register handling to allow
processes using EBB (Event Based Branches) to request access to the BHRB
(Branch History Rolling Buffer).

With that in place we can allow processes using EBB to access the BHRB.
This is achieved by setting BHRBA in MMCR0 when we enable EBB access. We
must also clear BHRBA when we are disabling.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Some power8 revisions have a hardware bug where we can lose a PMU
exception, this commit adds a workaround to detect the bad condition and
rectify the situation.

See the comment in the commit for a full description.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).

In commit 8b64a9df ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:

 - It's incompatible with EXCEPTION_COMMON which restores r13 from the
   by-then-overwritten scratch (this cost me some debugging time).
 - It forces critical exceptions to be a special case handled
   differently from even machine check and debug level exceptions.
 - It didn't occur to me that it was possible to make this work at all
   (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
   I made (most of) this patch. :-)

It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles.  Until then, let's stick with
SPRG for all exceptions.

Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e.  Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org

Signed-off-by: NWang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

The DABRX (DABR extension) register on POWER7 processors provides finer
control over which accesses cause a data breakpoint interrupt.  It
contains 3 bits which indicate whether to enable accesses in user,
kernel and hypervisor modes respectively to cause data breakpoint
interrupts, plus one bit that enables both real mode and virtual mode
accesses to cause interrupts.  Currently, KVM sets DABRX to allow
both kernel and user accesses to cause interrupts while in the guest.

This adds support for the guest to specify other values for DABRX.
PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR
and DABRX with one call.  This adds a real-mode implementation of
H_SET_XDABR, which shares most of its code with the existing H_SET_DABR
implementation.  To support this, we add a per-vcpu field to store the
DABRX value plus code to get and set it via the ONE_REG interface.

For Linux guests to use this new hcall, userspace needs to add
"hcall-xdabr" to the set of strings in the /chosen/hypertas-functions
property in the device tree.  If userspace does this and then migrates
the guest to a host where the kernel doesn't include this patch, then
userspace will need to implement H_SET_XDABR by writing the specified
DABR value to the DABR using the ONE_REG interface.  In that case, the
old kernel will set DABRX to DABRX_USER | DABRX_KERNEL.  That should
still work correctly, at least for Linux guests, since Linux guests
cope with getting data breakpoint interrupts in modes that weren't
requested by just ignoring the interrupt, and Linux guests never set
DABRX_BTI.

The other thing this does is to make H_SET_DABR and H_SET_XDABR work
on POWER8, which has the DAWR and DAWRX instead of DABR/X.  Guests that
know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but
guests running in POWER7 compatibility mode will still use H_SET_[X]DABR.
For them, this adds the logic to convert DABR/X values into DAWR/X values
on POWER8.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

POWER8 has a bit in the LPCR to enable or disable the PURR and SPURR
registers to count when in the guest.  Set this bit.

POWER8 has a field in the LPCR called AIL (Alternate Interrupt Location)
which is used to enable relocation-on interrupts.  Allow userspace to
set this field.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

* SRR1 wake reason field for system reset interrupt on wakeup from nap
  is now a 4-bit field on P8, compared to 3 bits on P7.

* Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells
  will wake us up.

* Waking up from nap because of a guest doorbell interrupt is not a
  reason to exit the guest.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This allows us to select architecture 2.05 (POWER6) or 2.06 (POWER7)
compatibility modes on a POWER8 processor.  (Note that transactional
memory is disabled for usermode if either or both of the PCR_TM_DIS
and PCR_ARCH_206 bits are set.)
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This adds fields to the struct kvm_vcpu_arch to store the new
guest-accessible SPRs on POWER8, adds code to the get/set_one_reg
functions to allow userspace to access this state, and adds code to
the guest entry and exit to context-switch these SPRs between host
and guest.

Note that DPDES (Directed Privileged Doorbell Exception State) is
shared between threads on a core; hence we store it in struct
kvmppc_vcore and have the master thread save and restore it.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

E6500 PVR and SPRN_PWRMGTCR0 will be used in subsequent pw20/altivec
idle patches.
Signed-off-by: NWang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

Commit beb2dc0a breaks the MPC8xx which
seems to not support using mfspr SPRN_TBRx instead of mftb/mftbu
despite what is written in the reference manual.

This patch reverts to the use of mftb/mftbu when CONFIG_8xx is
selected.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NScott Wood <scottwood@freescale.com>

This enables us to use the Processor Compatibility Register (PCR) on
POWER7 to put the processor into architecture 2.05 compatibility mode
when running a guest.  In this mode the new instructions and registers
that were introduced on POWER7 are disabled in user mode.  This
includes all the VSX facilities plus several other instructions such
as ldbrx, stdbrx, popcntw, popcntd, etc.

To select this mode, we have a new register accessible through the
set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT.  Setting
this to zero gives the full set of capabilities of the processor.
Setting it to one of the "logical" PVR values defined in PAPR puts
the vcpu into the compatibility mode for the corresponding
architecture level.  The supported values are:

0x0f000002	Architecture 2.05 (POWER6)
0x0f000003	Architecture 2.06 (POWER7)
0x0f100003	Architecture 2.06+ (POWER7+)

Since the PCR is per-core, the architecture compatibility level and
the corresponding PCR value are stored in the struct kvmppc_vcore, and
are therefore shared between all vcpus in a virtual core.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
[agraf: squash in fix to add missing break statements and documentation]
Signed-off-by: NAlexander Graf <agraf@suse.de>

This adds the ability to have a separate LPCR (Logical Partitioning
Control Register) value relating to a guest for each virtual core,
rather than only having a single value for the whole VM.  This
corresponds to what real POWER hardware does, where there is a LPCR
per CPU thread but most of the fields are required to have the same
value on all active threads in a core.

The per-virtual-core LPCR can be read and written using the
GET/SET_ONE_REG interface.  Userspace can can only modify the
following fields of the LPCR value:

DPFD	Default prefetch depth
ILE	Interrupt little-endian
TC	Translation control (secondary HPT hash group search disable)

We still maintain a per-VM default LPCR value in kvm->arch.lpcr, which
contains bits relating to memory management, i.e. the Virtualized
Partition Memory (VPM) bits and the bits relating to guest real mode.
When this default value is updated, the update needs to be propagated
to the per-vcore values, so we add a kvmppc_update_lpcr() helper to do
that.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
[agraf: fix whitespace]
Signed-off-by: NAlexander Graf <agraf@suse.de>

This allows guests to have a different timebase origin from the host.
This is needed for migration, where a guest can migrate from one host
to another and the two hosts might have a different timebase origin.
However, the timebase seen by the guest must not go backwards, and
should go forwards only by a small amount corresponding to the time
taken for the migration.

Therefore this provides a new per-vcpu value accessed via the one_reg
interface using the new KVM_REG_PPC_TB_OFFSET identifier.  This value
defaults to 0 and is not modified by KVM.  On entering the guest, this
value is added onto the timebase, and on exiting the guest, it is
subtracted from the timebase.

This is only supported for recent POWER hardware which has the TBU40
(timebase upper 40 bits) register.  Writing to the TBU40 register only
alters the upper 40 bits of the timebase, leaving the lower 24 bits
unchanged.  This provides a way to modify the timebase for guest
migration without disturbing the synchronization of the timebase
registers across CPU cores.  The kernel rounds up the value given
to a multiple of 2^24.

Timebase values stored in KVM structures (struct kvm_vcpu, struct
kvmppc_vcore, etc.) are stored as host timebase values.  The timebase
values in the dispatch trace log need to be guest timebase values,
however, since that is read directly by the guest.  This moves the
setting of vcpu->arch.dec_expires on guest exit to a point after we
have restored the host timebase so that vcpu->arch.dec_expires is a
host timebase value.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

We need to set MSR_LE in kernel and userspace for little endian builds
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Commit 74e400ce ("powerpc: Rework setting up H/FSCR bit definitions")
ended up with incorrect bit numbers for FSCR_PM_LG and FSCR_BHRB_LG.
This fixes them.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Some CPUs (such as e500v1/v2) don't implement mftb and will take a
trap.  mfspr should work on everything that has a timebase, and is the
preferred instruction according to ISA v2.06.

Currently we get away with mftb on 85xx because the assembler converts
it to mfspr due to -Wa,-me500.  However, that flag has other effects
that are undesireable for certain targets (e.g.  lwsync is converted to
sync), and is hostile to multiplatform kernels.  Thus we would like to
stop setting it for all e500-family builds.

mftb/mftbu instances which are in 85xx code or common code are
converted.  Instances which will never run on 85xx are left alone.
Signed-off-by: NScott Wood <scottwood@freescale.com>

Erratum A-006598 says that 64-bit mftb is not atomic -- it's subject
to a similar race condition as doing mftbu/mftbl on 32-bit.  The lower
half of timebase is updated before the upper half; thus, we can share
the workaround for a similar bug on Cell.  This workaround involves
looping if the lower half of timebase is zero, thus avoiding the need
for a scratch register (other than CR0).  This workaround must be
avoided when the timebase is frozen, such as during the timebase sync
code.

This deals with kernel and vdso accesses, but other userspace accesses
will of course need to be fixed elsewhere.
Signed-off-by: NScott Wood <scottwood@freescale.com>

Not having parentheses around a macro is asking for trouble.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This reworks the Facility Status and Control Regsiter (FSCR) config bit
definitions so that we can access the bit numbers.  This is needed for a
subsequent patch to fix the userspace DSCR handling.

HFSCR and FSCR bit definitions are the same, so reuse them.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> [v3.10]
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

POWER8 comes with two different PVRs.  This patch enables the additional
PVR in the cputable.

The existing entry (PVR=0x4b) is renamed to POWER8E and the new entry
(PVR=0x4d) is given POWER8.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Add support for EBB (Event Based Branches) on 64-bit book3s. See the
included documentation for more details.

EBBs are a feature which allows the hardware to branch directly to a
specified user space address when a PMU event overflows. This can be
used by programs for self-monitoring with no kernel involvement in the
inner loop.

Most of the logic is in the generic book3s code, primarily to avoid a
proliferation of PMU callbacks.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On Power8 we can freeze PMC5 and 6 if we're not using them. Normally they
run all the time.

As noticed by Anshuman, we should unfreeze them when we disable the PMU
as there are legacy tools which expect them to run all the time.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
CC: <stable@vger.kernel.org> [v3.10]
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

These cause codes are usable by userspace, so let's export to uapi.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If we are emulating an instruction inside an active user transaction that
touches memory, the kernel can't emulate it as it operates in transactional
suspend context.  We need to abort these transactions and send them back to
userspace for the hardware to rollback.

We can service these if the user transaction is in suspend mode, since the
kernel will operate in the same suspend context.

This adds a check to all alignment faults and to specific instruction
emulations (only string instructions for now).  If the user process is in an
active (non-suspended) transaction, we abort the transaction go back to
userspace allowing the HW to roll back the transaction and tell the user of the
failure.  This also adds new tm abort cause codes to report the reason of the
persistent error to the user.

Crappy test case here http://neuling.org/devel/junkcode/aligntm.cSigned-off-by: NMichael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

PAPR carves out 0xff-0xe0 for hypervisor use of transactional memory software
abort cause codes.  Unfortunately we don't respect this currently.

Below fixes this to move our cause codes to below this region.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> # 3.9 only
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>