Commit graph

77 commits

Author SHA1 Message Date
Nicholas Piggin bc276ecba1 powerpc/64s/hash: Do not use PPC_INVALIDATE_ERAT on CPUs before POWER9
PPC_INVALIDATE_ERAT is slbia IH=7 which is a new variant introduced
with POWER9, and the result is undefined on earlier CPUs.

Commits 7b9f71f974 ("powerpc/64s: POWER9 machine check handler") and
d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on
POWER9") caused POWER7/8 code to use this instruction. Remove it. An
ERAT flush can be made by invalidatig the SLB, but before POWER9 that
requires a flush and rebolt.

Fixes: 7b9f71f974 ("powerpc/64s: POWER9 machine check handler")
Fixes: d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-04 23:16:53 +10:00
Christophe Leroy 45ef5992e0 powerpc: remove unnecessary inclusion of asm/tlbflush.h
asm/tlbflush.h is only needed for:
- using functions xxx_flush_tlb_xxx()
- using MMU_NO_CONTEXT
- including asm-generic/pgtable.h

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-30 22:48:20 +10:00
Christophe Leroy 2c86cd188f powerpc: clean inclusions of asm/feature-fixups.h
files not using feature fixup don't need asm/feature-fixups.h
files using feature fixup need asm/feature-fixups.h

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-30 22:48:17 +10:00
Aneesh Kumar K.V 27d8959da7 powerpc/mm/hash: Reduce contention on hpte lock
We do this in some part. This patch make sure we always try to search
for hpte without holding lock and redo the compare with lock held once
match found.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-24 22:03:18 +10:00
Aneesh Kumar K.V a833280b4a powerpc/mm/hash: Add hpte_get_old_v and use that instead of opencoding
No functional change

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-24 22:03:18 +10:00
Michael Ellerman 95dff480bb Merge branch 'fixes' into next
Merge our fixes branch from the 4.16 cycle.

There were a number of important fixes merged, in particular some Power9
workarounds that we want in next for testing purposes. There's also been
some conflicting changes in the CPU features code which are best merged
and tested before going upstream.
2018-03-28 22:59:50 +11:00
Aneesh Kumar K.V a5d4b5891c powerpc/mm: Fixup tlbie vs store ordering issue on POWER9
On POWER9, under some circumstances, a broadcast TLB invalidation
might complete before all previous stores have drained, potentially
allowing stale stores from becoming visible after the invalidation.
This works around it by doubling up those TLB invalidations which was
verified by HW to be sufficient to close the risk window.

This will be documented in a yet-to-be-published errata.

Fixes: 1a472c9dba ("powerpc/mm/radix: Add tlbflush routines")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Enable the feature in the DT CPU features code for all Power9,
      rename the feature to CPU_FTR_P9_TLBIE_BUG per benh.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-23 20:48:03 +11:00
Anshuman Khandual 3d4f5f5848 powerpc/mm: Drop the function native_register_proc_table()
This is left over from the segment table implementation and not getting
called from any where now. Hence just drop it.

Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-13 15:50:27 +11:00
Nicholas Piggin d4748276ae powerpc/64s: Improve local TLB flush for boot and MCE on POWER9
There are several cases outside the normal address space management
where a CPU's entire local TLB is to be flushed:

  1. Booting the kernel, in case something has left stale entries in
     the TLB (e.g., kexec).

  2. Machine check, to clean corrupted TLB entries.

One other place where the TLB is flushed, is waking from deep idle
states. The flush is a side-effect of calling ->cpu_restore with the
intention of re-setting various SPRs. The flush itself is unnecessary
because in the first case, the TLB should not acquire new corrupted
TLB entries as part of sleep/wake (though they may be lost).

This type of TLB flush is coded inflexibly, several times for each CPU
type, and they have a number of problems with ISA v3.0B:

- The current radix mode of the MMU is not taken into account, it is
  always done as a hash flushn For IS=2 (LPID-matching flush from host)
  and IS=3 with HV=0 (guest kernel flush), tlbie(l) is undefined if
  the R field does not match the current radix mode.

- ISA v3.0B hash must flush the partition and process table caches as
  well.

- ISA v3.0B radix must flush partition and process scoped translations,
  partition and process table caches, and also the page walk cache.

So consolidate the flushing code and implement it in C and inline asm
under the mm/ directory with the rest of the flush code. Add ISA v3.0B
cases for radix and hash, and use the radix flush in radix environment.

Provide a way for IS=2 (LPID flush) to specify the radix mode of the
partition. Have KVM pass in the radix mode of the guest.

Take out the flushes from early cputable/dt_cpu_ftrs detection hooks,
and move it later in the boot process after, the MMU registers are set
up and before relocation is first turned on.

The TLB flush is no longer called when restoring from deep idle states.
This was not be done as a separate step because booting secondaries
uses the same cpu_restore as idle restore, which needs the TLB flush.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-18 00:40:31 +11:00
Mahesh Salgaonkar a3961f824c powerpc/powernv: Fix kexec crashes caused by tlbie tracing
Rebooting into a new kernel with kexec fails in trace_tlbie() which is
called from native_hpte_clear(). This happens if the running kernel
has CONFIG_LOCKDEP enabled. With lockdep enabled, the tracepoints
always execute few RCU checks regardless of whether tracing is on or
off. We are already in the last phase of kexec sequence in real mode
with HILE_BE set. At this point the RCU check ends up in
RCU_LOCKDEP_WARN and causes kexec to fail.

Fix this by not calling trace_tlbie() from native_hpte_clear().

mpe: It's not safe to call trace points at this point in the kexec
path, even if we could avoid the RCU checks/warnings. The only
solution is to not call them.

Fixes: 0428491cba ("powerpc/mm: Trace tlbie(l) instructions")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-23 23:10:14 +11:00
Anton Blanchard 1b644f57b3 powerpc/mm: Wire up hpte_removebolted for powernv
Adds support for removing bolted (i.e kernel linear mapping) mappings on
powernv. This is needed to support memory hot unplug operations which
are required for the teardown of DAX/PMEM devices.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:28 +10:00
Nicholas Piggin 4e287e655e powerpc: use spin loop primitives in some functions
Use the different spin loop primitives in some simple powerpc
spin loops, including those which will spin as a common case.

This will help to test the spin loop primitives before more
conversions are done.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add some includes of <linux/processor.h>]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:24 +10:00
Balbir Singh 0428491cba powerpc/mm: Trace tlbie(l) instructions
Add a trace point for tlbie(l) (Translation Lookaside Buffer Invalidate
Entry (Local)) instructions.

The tlbie instruction has changed over the years, so not all versions
accept the same operands. Use the ISA v3 field operands because they are
the most verbose, we may change them in future.

Example output:

  qemu-system-ppc-5371  [016]  1412.369519: tlbie:
  	tlbie with lpid 0, local 1, rb=67bd8900174c11c1, rs=0, ric=0 prs=0 r=0

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Add some missing trace_tlbie()s, reword change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-23 21:14:49 +10:00
Frederic Barrat 88b1bf7268 powerpc/mm: Add missing global TLB invalidate if cxl is active
Commit 4c6d9acce1 ("powerpc/mm: Add hooks for cxl") converted local
TLB invalidates to global if the cxl driver is active. This is necessary
because the CAPP snoops invalidations to forward them to the PSL on the
cxl adapter. However one path was forgotten. native_flush_hash_range()
still does local TLB invalidates, as found out the hard way recently.

This patch fixes it by following the same logic as previously: if the
cxl driver is active, the local TLB invalidates are 'upgraded' to
global.

Fixes: 4c6d9acce1 ("powerpc/mm: Add hooks for cxl")
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-05 22:13:37 +10:00
Michael Ellerman ddbefe7e77 Merge branch 'topic/ppc-kvm' into next
Merge the topic branch we're sharing with the kvm-ppc tree.
2016-11-24 22:14:52 +11:00
Paul Mackerras 6b243fcfb5 powerpc/64: Simplify adaptation to new ISA v3.00 HPTE format
This changes the way that we support the new ISA v3.00 HPTE format.
Instead of adapting everything that uses HPTE values to handle either
the old format or the new format, depending on which CPU we are on,
we now convert explicitly between old and new formats if necessary
in the low-level routines that actually access HPTEs in memory.
This limits the amount of code that needs to know about the new
format and makes the conversions explicit.  This is OK because the
old format contains all the information that is in the new format.

This also fixes operation under a hypervisor, because the H_ENTER
hypercall (and other hypercalls that deal with HPTEs) will continue
to require the HPTE value to be supplied in the old format.  At
present the kernel will not boot in HPT mode on POWER9 under a
hypervisor.

This fixes and partially reverts commit 50de596de8
("powerpc/mm/hash: Add support for Power9 Hash", 2016-04-29).

Fixes: 50de596de8 ("powerpc/mm/hash: Add support for Power9 Hash")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-11-16 15:43:25 +11:00
Balbir Singh f923efbcfd powerpc/hash64: Be more careful when generating tlbiel
In ISA v2.05, the tlbiel instruction takes two arguments, RB and L:

tlbiel RB,L

+---------+---------+----+---------+---------+---------+----+
|    31   |    /    | L  |    /    |    RB   |   274   | /  |
| 31 - 26 | 25 - 22 | 21 | 20 - 16 | 15 - 11 |  10 - 1 | 0  |
+---------+---------+----+---------+---------+---------+----+

In ISA v2.06 tlbiel takes only one argument, RB:

tlbiel RB

+---------+---------+---------+---------+---------+----+
|    31   |    /    |    /    |    RB   |   274   | /  |
| 31 - 26 | 25 - 21 | 20 - 16 | 15 - 11 |  10 - 1 | 0  |
+---------+---------+---------+---------+---------+----+

And in ISA v3.00 tlbiel takes five arguments:

tlbiel RB,RS,RIC,PRS,R

+---------+---------+----+---------+----+----+---------+---------+----+
|    31   |    RS   | /  |   RIC   |PRS | R  |    RB   |   274   | /  |
| 31 - 26 | 25 - 21 | 20 | 19 - 18 | 17 | 16 | 15 - 11 |  10 - 1 | 0  |
+---------+---------+----+---------+----+----+---------+---------+----+

However the assembler also accepts "tlbiel RB", and generates
"tlbiel RB,r0,0,0,0".

As you can see above the L field from the v2.05 encoding overlaps with the
reserved field of the v2.06 encoding, and the low bit of the RS field of the
v3.00 encoding.

Currently in __tlbiel() we generate two tlbiel instructions manually using hex
constants. In the first case, for MMU_PAGE_4K, we generate "tlbiel RB,0", which
is safe in all cases, because the L bit is zero.

However in the default case we generate "tlbiel RB,1", therefore setting bit 21
to 1.

This is not an actual bug on v2.06 processors, because the CPU ignores the value
of the reserved field. However software is supposed to encode the reserved
fields as zero to enable forward compatibility.

On v3.00 processors setting bit 21 to 1 and no other bits of RS, means we are
using r1 for the value of RS.

Although it's not obvious, the code sets the IS field (bits 10-11) to 0 (by
omission), and L=1, in the va value, which is passed as RB. We also pass R=0 in
the instruction.

The combination of IS=0, L=1 and R=0 means the value of RS is not used, so even
on ISA v3.00 there is no actual bug.

We should still fix it, as setting a reserved bit on v2.06 is naughty, and we
are only avoiding a bug on v3.00 by accident rather than design. Use
ASM_FTR_IFSET() to generate the single argument form on ISA v2.06 and later, and
the two argument form on pre v2.06.

Although there may be very old toolchains which don't understand tlbiel, we have
other code in the tree which has been using tlbiel for over five years, and no
one has reported any build failures, so just let the assembler generate the
instructions.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Rewrite change log, use IFSET instead of IFCLR]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-11-14 11:11:51 +11:00
Paul Mackerras 0eeede0c63 powerpc/mm: Speed up computation of base and actual page size for a HPTE
This replaces a 2-D search through an array with a simple 8-bit table
lookup for determining the actual and/or base page size for a HPT entry.

The encoding in the second doubleword of the HPTE is designed to encode
the actual and base page sizes without using any more bits than would be
needed for a 4k page number, by using between 1 and 8 low-order bits of
the RPN (real page number) field to encode the page sizes.  A single
"large page" bit in the first doubleword indicates that these low-order
bits are to be interpreted like this.

We can determine the page sizes by using the low-order 8 bits of the RPN
to look up a 256-entry table.  For actual page sizes less than 1MB, some
of the upper bits of these 8 bits are going to be real address bits, but
we can cope with that by replicating the entries for those smaller page
sizes.

While we're at it, let's move the hpte_page_size() and hpte_base_page_size()
functions from a KVM-specific header to a header for 64-bit HPT systems,
since this computation doesn't have anything specifically to do with KVM.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2016-09-09 16:14:48 +10:00
Michael Ellerman eea8148c69 powerpc/mm: Move register_process_table() out of ppc_md
We want to initialise register_process_table() before ppc_md is setup,
so that it can be called as part of MMU init (at least on Radix ATM).

That no longer works because probe_machine() requires that ppc_md be
empty before it's called, and we now do probe_machine() much later.

So make register_process_table a global for now. It will probably move
into a mmu_radix_ops struct at some point in the future.

This was broken by me when applying commit 7025776ed1 "powerpc/mm:
Move hash table ops to a separate structure" due to conflicts with other
patches.

Fixes: 7025776ed1 ("powerpc/mm: Move hash table ops to a separate structure")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-04 20:22:34 +10:00
Aneesh Kumar K.V 138ee7ee01 powerpc/mm/hash: Add helper for finding SLBE LLP encoding
Replace opencoding of the same at multiple places with the helper.
No functional change with this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-01 11:15:08 +10:00
Benjamin Herrenschmidt 7025776ed1 powerpc/mm: Move hash table ops to a separate structure
Moving probe_machine() to after mmu init will cause the ppc_md
fields relative to the hash table management to be overwritten.

Since we have essentially disconnected the machine type from
the hash backend ops, finish the job by moving them to a different
structure.

The only callback that didn't quite fix is update_partition_table
since this is not specific to hash, so I moved it to a standalone
variable for now. We can revisit later if needed.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Fix ppc64e build failure in kexec]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-21 18:59:09 +10:00
Aneesh Kumar K.V 83209bc861 powerpc/mm/radix: Update machine call back to support new HCALL.
This update the machine dep callback such that we can use the same
callback to register process table. The interface is updated such that
we can easily call H_REGISTER_PROC_TBL hcall. The HCALL itself is
introduced in a later patch.

No functionality change introduced by this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-17 16:42:54 +10:00
Aneesh Kumar K.V accfad7d0a powerpc/mm: Clear top 16 bits of va only on older cpus
As per ISA, we need to do this only for architecture version 2.02 and
earlier. This continued to work even for 2.07. But let's not do this for
anything after 2.02. ISA 3.0 requires these top bits to be not cleared.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-17 16:42:52 +10:00
Michael Ellerman b5f1bf48f2 powerpc fixes for 4.7 #5
- tm: Always reclaim in start_thread() for exec() class syscalls from Cyril Bur
  - tm: Avoid SLB faults in treclaim/trecheckpoint when RI=0 from Michael Neuling
  - eeh: Fix wrong argument passed to eeh_rmv_device() from Gavin Shan
  - Initialise pci_io_base as early as possible from Darren Stevens
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Merge tag 'powerpc-4.7-5' into next

Pull in the fixes we sent during 4.7, we have code we want to merge into
next that depends on some of them.
2016-07-15 14:57:47 +10:00
Michael Ellerman 027dfac694 powerpc: Various typo fixes
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-14 13:58:26 +10:00
Aneesh Kumar K.V 8550e2fa34 powerpc/mm/hash: Use the correct PPP mask when updating HPTE
With commit e58e87adc8 "powerpc/mm: Update _PAGE_KERNEL_RO" we now
use all the three PPP bits. The top bit is now used to have a PPP value
of 0b110 which will be mapped to kernel read only. When updating the
hpte entry use right mask such that we update the 63rd bit (top 'P' bit)
too.

Prior to e58e87adc8 we didn't support KERNEL_RO at all (it was ==
KERNEL_RW), so this isn't a regression as such.

Fixes: e58e87adc8 ("powerpc/mm: Update _PAGE_KERNEL_RO")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-14 13:54:51 +10:00
Aneesh Kumar K.V 3b6d1eb7ea powerpc/mm/hash: Compute the segment size correctly for ISA 3.0
PowerISA 3.0 encodes the segment size in the second half of hash page
table entry. Update hpte_decode() accordingly.

Fixes: 50de596de8 ("powerpc/mm/hash: Add support for Power9 Hash")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-08 14:36:22 +10:00
Aneesh Kumar K.V 50de596de8 powerpc/mm/hash: Add support for Power9 Hash
PowerISA 3.0 adds a parition table indexed by LPID. Parition table
allows us to specify the MMU model that will be used for guest and host
translation.

This patch adds support with SLB based hash model (UPRT = 0). What is
required with this model is to support the new hash page table entry
format and also setup partition table such that we use hash table for
address translation.

We don't have segment table support yet.

In order to make sure we don't load KVM module on Power9 (since we don't
have kvm support yet) this patch also disables KVM on Power9.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:40 +10:00
Aneesh Kumar K.V e34aa03ca4 powerpc/mm: Move THP headers around
We support THP only with book3s_64 and 64K page size. Move
THP details to hash64-64k.h to clarify the same.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:14 +11:00
Cyril Bur fdf880a608 powerpc: Fix checkstop in native_hpte_clear() with lockdep
native_hpte_clear() is called in real mode from two places:
- Early in boot during htab initialisation if firmware assisted dump is
  active.
- Late in the kexec path.

In both contexts there is no need to disable interrupts are they are
already disabled. Furthermore, locking around the tlbie() is only required
for pre POWER5 hardware.

On POWER5 or newer hardware concurrent tlbie()s work as expected and on pre
POWER5 hardware concurrent tlbie()s could result in deadlock. This code
would only be executed at crashdump time, during which all bets are off,
concurrent tlbie()s are unlikely and taking locks is unsafe therefore the
best course of action is to simply do nothing. Concurrent tlbie()s are not
possible in the first case as secondary CPUs have not come up yet.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-09 08:01:38 +11:00
Michael Neuling ec249dd860 cxl: Move include file cxl.h -> cxl-base.h
This moves the current include file from cxl.h -> cxl-base.h.  This current
include file is used only to pass information between the base driver that
needs to be built into the kernel and the cxl module.

This is to make way for a new include/misc/cxl.h which will
contain just the kernel API for other driver to use

Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-03 13:27:19 +10:00
Aneesh Kumar K.V aefa5688c0 powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
upatepp can get called for a nohpte fault when we find from the linux
page table that the translation was hashed before. In that case
we are sure that there is no existing translation, hence we could
avoid doing tlbie.

We could possibly race with a parallel fault filling the TLB. But
that should be ok because updatepp is only ever relaxing permissions.
We also look at linux pte permission bits when filling hash pte
permission bits. We also hold the linux pte busy bits while
inserting/updating a hashpte entry, hence a paralle update of
linux pte is not possible. On the other hand mprotect involves
ptep_modify_prot_start which cause a hpte invalidate and not updatepp.

Performance number:
We use randbox_access_bench written by Anton.

Kernel with THP disabled and smaller hash page table size.

    86.60%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_updatepp
     2.10%  random_access_b  random_access_bench              [.] doit
     1.99%  random_access_b  [kernel.kallsyms]                [k] .do_raw_spin_lock
     1.85%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     1.26%  random_access_b  [kernel.kallsyms]                [k] .native_flush_hash_range
     1.18%  random_access_b  [kernel.kallsyms]                [k] .__delay
     0.69%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     0.37%  random_access_b  [kernel.kallsyms]                [k] .clear_user_page
     0.34%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     0.32%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     0.30%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm

With Fix:

    27.54%  random_access_b  random_access_bench              [.] doit
    22.90%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     5.76%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     5.20%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     5.12%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     4.80%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm
     3.31%  random_access_b  [kernel.kallsyms]                [k] data_access_common
     1.84%  random_access_b  [kernel.kallsyms]                [k] .trace_hardirqs_on_caller

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05 16:26:15 +11:00
Aneesh Kumar K.V d557b09800 powerpc/mm/thp: Use tlbiel if possible
If we know that user address space has never executed on other cpus
we could use tlbiel.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-12-02 14:10:11 +11:00
Aneesh Kumar K.V 0ec2698fe1 powerpc/mm: Check for matching hpte without taking hpte lock
With smaller hash page table config, we would end up in situation
where we would be replacing hash page table slot frequently. In
such config, we will find the hpte to be not matching, and we
can do that check without holding the hpte lock. We need to
recheck the hpte again after holding lock.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-12-02 11:03:45 +11:00
Christoph Lameter 69111bac42 powerpc: Replace __get_cpu_var uses
This still has not been merged and now powerpc is the only arch that does
not have this change. Sorry about missing linuxppc-dev before.

V2->V2
  - Fix up to work against 3.18-rc1

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
[mpe: Fix build errors caused by set/or_softirq_pending(), and rework
      assignment in __set_breakpoint() to use memcpy().]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-03 12:12:32 +11:00
Ian Munsie 4c6d9acce1 powerpc/mm: Add hooks for cxl
This adds hooks into the core powerpc mm code for cxl.

The core powerpc code sometimes uses local tlbie. Unfortunately this won't
work with the current cxl driver as it relies on snooping tlbie broadcasts.

The cxl hardware can have TLB entries invalidated via MMIO but this is not
currently supported by the driver. In future we can make local tlbie smarter so
that it invalidates cxl contexts via MMIO when it needs to but for now we have
this workaround.

This workaround checks for any active cxl contexts and if so, disables local
tlbie.

This also adds a hook for when SLBs are invalidated. This ensures any
corresponding SLBs in cxl are also invalidated at the same time. This is
required for segment demotion.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-10-08 20:15:55 +11:00
Aneesh Kumar K.V 969b7b208f powerpc/thp: Invalidate with vpn in loop
As per ISA, for 4k base page size we compare 14..65 bits of VA specified
with the entry_VA in tlb. That implies we need to make sure we do a
tlbie with all the possible 4k va we used to access the 16MB hugepage.
With 64k base page size we compare 14..57 bits of VA. Hence we cannot
ignore the lower 24 bits of va while tlbie .We also cannot tlb
invalidate a 16MB entry with just one tlbie instruction because
we don't track which va was used to instantiate the tlb entry.

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:40 +10:00
Aneesh Kumar K.V fa1f8ae80f powerpc/thp: Don't recompute vsid and ssize in loop on invalidate
The segment identifier and segment size will remain the same in
the loop, So we can compute it outside. We also change the
hugepage_invalidate interface so that we can use it the later patch

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 18:20:38 +10:00
Aneesh Kumar K.V 29ef7a3e26 powerpc/mm: Fix tlbie to add AVAL fields for 64K pages
The if condition check was based on a draft ISA doc. Remove the same.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:11:24 +10:00
Anton Blanchard 12f04f2be8 powerpc: Book 3S MMU little endian support
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 16:48:26 +11:00
Aneesh Kumar K.V de640959b6 powerpc/mm: Use the correct SLB(LLP) encoding in tlbie instruction
The sllp value is stored in mmu_psize_defs in such a way that we can easily OR
the value to get the operand for slbmte instruction. ie, the L and LP bits are
not contiguous. Decode the bits and use them correctly in tlbie.
regression is introduced by 1f6aaaccb1
"powerpc: Update tlbie/tlbiel as per ISA doc"

Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-07-24 14:42:24 +10:00
Aneesh Kumar K.V 83383b73ad powerpc/mm: Fix fallthrough bug in hpte_decode
We should not fallthrough different case statements in hpte_decode. Add
break statement to break out of the switch. The regression is introduced by
dcda287a9b "powerpc/mm: Simplify hpte_decode"

Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-07-24 14:42:21 +10:00
Aneesh Kumar K.V 1a5272866f powerpc: Optimize hugepage invalidate
Hugepage invalidate involves invalidating multiple hpte entries.
Optimize the operation using H_BULK_REMOVE on lpar platforms.
On native, reduce the number of tlb flush.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-21 16:01:58 +10:00
Aneesh Kumar K.V db3d853490 powerpc/mm: handle hugepage size correctly when invalidating hpte entries
If a hash bucket gets full, we "evict" a more/less random entry from it.
When we do that we don't invalidate the TLB (hpte_remove) because we assume
the old translation is still technically "valid". This implies that when
we are invalidating or updating pte, even if HPTE entry is not valid
we should do a tlb invalidate. With hugepages, we need to pass the correct
actual page size value for tlb invalidation.

This change update the patch 0608d69246
"powerpc/mm: Always invalidate tlb on hpte invalidate and update" to handle
transparent hugepages correctly.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-21 16:01:52 +10:00
Aneesh Kumar K.V 0608d69246 powerpc/mm: Always invalidate tlb on hpte invalidate and update
If a hash bucket gets full, we "evict" a more/less random entry from it.
When we do that we don't invalidate the TLB (hpte_remove) because we assume
the old translation is still technically "valid". This implies that when
we are invalidating or updating pte, even if HPTE entry is not valid
we should do a tlb invalidate.

This was a regression introduced by b1022fbd29

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-01 08:29:26 +10:00
Aneesh Kumar K.V 1f6aaaccb1 powerpc: Update tlbie/tlbiel as per ISA doc
Encode the actual page correctly in tlbie/tlbiel. This make sure we handle
multiple page size segment correctly.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-30 16:00:29 +10:00
Aneesh Kumar K.V 7e74c3921a powerpc: Fix hpte_decode to use the correct decoding for page sizes
As per ISA doc, we encode base and actual page size in the LP bits of
PTE. The number of bit used to encode the page sizes depend on actual
page size.  ISA doc lists this as

   PTE LP     actual page size
rrrr rrrz 	>=8KB
rrrr rrzz	>=16KB
rrrr rzzz 	>=32KB
rrrr zzzz 	>=64KB
rrrz zzzz 	>=128KB
rrzz zzzz 	>=256KB
rzzz zzzz	>=512KB
zzzz zzzz 	>=1MB

ISA doc also says
"The values of the “z” bits used to specify each size, along with all possible
values of “r” bits in the LP field, must result in LP values distinct from
other LP values for other sizes."

based on the above update hpte_decode to use the correct decoding for LP bits.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-30 16:00:18 +10:00
Aneesh Kumar K.V b1022fbd29 powerpc: Decode the pte-lp-encoding bits correctly.
We look at both the segment base page size and actual page size and store
the pte-lp-encodings in an array per base page size.

We also update all relevant functions to take actual page size argument
so that we can use the correct PTE LP encoding in HPTE. This should also
get the basic Multiple Page Size per Segment (MPSS) support. This is needed
to enable THP on ppc64.

[Fixed PR KVM build --BenH]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-30 16:00:14 +10:00
Aneesh Kumar K.V 74f227b228 powerpc: Use encode avpn where we need only avpn values
In all these cases we are doing something similar to

HPTE_V_COMPARE(hpte_v, want_v) which ignores the HPTE_V_LARGE bit

With MPSS support we would need actual page size to set HPTE_V_LARGE
bit and that won't be available in most of these cases. Since we are ignoring
HPTE_V_LARGE bit, use the  avpn value instead. There should not be any change
in behaviour after this patch.

Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-30 16:00:11 +10:00
Michael Ellerman 8e166991c0 powerpc: Remove tlb batching hack for nighthawk
In hpte_init_native() we call tlb_batching_enabled() to decide if we
should setup ppc_md.flush_hash_range.

tlb_batching_enabled() checks the _unflattened_ device tree, to see
if we are running on a nighthawk.

Since commit a223535 ("dont allow pSeries_probe to succeed without
initialising MMU", Dec 2006), hpte_init_native() has been called from
pSeries_probe() - at which point we have not yet unflattened the
device tree.

This means tlb_batching_enabled() will always return true, so the hack
has effectively been disabled since Dec 2006. Ergo, I think we can
drop it.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-27 12:51:06 +10:00