powerpc/spufs: Remove set but not used variable 'dummy'

Fixes gcc '-Wunused-but-set-variable' warning:
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 does

powerpc/spufs: Remove set but not used variable 'dummy'

Fixes gcc '-Wunused-but-set-variable' warning:
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format
# WARNING: Fixes tag on line 3 doesn't match correct format

arch/powerpc/platforms/cell/spufs/switch.c: In function 'check_ppu_mb_stat':
arch/powerpc/platforms/cell/spufs/switch.c:1660:6: warning:
variable ‘dummy’ set but not used [-Wunused-but-set-variable]

arch/powerpc/platforms/cell/spufs/switch.c: In function 'check_ppuint_mb_stat':
arch/powerpc/platforms/cell/spufs/switch.c:1675:6: warning:
variable ‘dummy’ set but not used [-Wunused-but-set-variable]

It never used since introduction.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210601085127.139598-1-libaokun1@huawei.com

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powerpc/cell: Use fallthrough;

Convert the various uses of fallthrough comments to fallthrough;

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: M

powerpc/cell: Use fallthrough;

Convert the various uses of fallthrough comments to fallthrough;

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/03073a9a269010ca439e9e658629c44602b0cc9f.1583896348.git.joe@perches.com

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 or at your option any
later version this program is distributed in the hope that it will
be useful but without any warranty without even the implied warranty
of merchantability or fitness for a particular purpose see the gnu
general public license for more details you should have received a
copy of the gnu general public license along with this program if
not write to the free software foundation inc 675 mass ave cambridge
ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 77 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.837555891@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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powerpc: various straight conversions from module.h --> export.h

All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure. We can shift them off to the
export.h heade

powerpc: various straight conversions from module.h --> export.h

All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure. We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

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[POWERPC] spufs: handle faults while the context switch pending flag is set

Currently, page fault handlers don't issue a mfc restart if the context
switch pending flag is set, which can leave us wit

[POWERPC] spufs: handle faults while the context switch pending flag is set

Currently, page fault handlers don't issue a mfc restart if the context
switch pending flag is set, which can leave us with a hanging DMA after
a context restore.

This patch introduces fault pending flag that is set by the fault
handler and read by the context switch code, so that the latter can add
the restart bit at the right spot, after it has successfuly saved the
state of the mfc control register.

Signed-off-by: Luke Browning <lukebr@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: try to route SPU interrupts to local node

Currently, we re-route SPU interrupts to the current cpu, which may be
on a remote node. In the case of time slicing, all spu interrupts wi

[POWERPC] spufs: try to route SPU interrupts to local node

Currently, we re-route SPU interrupts to the current cpu, which may be
on a remote node. In the case of time slicing, all spu interrupts will
end up routed to the same cpu, where the spusched_tick occurs.

This change routes mfc interrupts to the cpu where the controlling
thread last ran, provided that cpu is on the same node as the spu
(otherwise don't reroute interrupts).

This should improve performance and provide a more predictable
environment for processing spu exceptions. In the past we have seen
concurrent delivery of spu exceptions to two cpus. This eliminates that
concern.

Signed-off-by: Luke Browning <lukebr@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: set SPU_CONTEXT_SWITCH_PENDING before synchronising SPU irqs

synchronize_irq() provides the serialization for
SPU_CONTEXT_SWITCH_PENDING which is read with a simple load. This
routi

[POWERPC] spufs: set SPU_CONTEXT_SWITCH_PENDING before synchronising SPU irqs

synchronize_irq() provides the serialization for
SPU_CONTEXT_SWITCH_PENDING which is read with a simple load. This
routine guarantees that the relevant interrupt handlers are not running,
so that the next time they do run they will see the update
memory value.

This must be done correctly so that exception handling code does not
restart the mfc in the middle of a context switch while we are trying
to atomically stop it and save state.

Signed-off-by: Luke Browning <lukebr@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: fix post-stopped update of MFC_CNTL register

We currently have two issues with the MFC save code:

* save_mfc_decr doesn't handle a transition of 1 -> 0 of the Ds bit
* The Q bit

[POWERPC] spufs: fix post-stopped update of MFC_CNTL register

We currently have two issues with the MFC save code:

* save_mfc_decr doesn't handle a transition of 1 -> 0 of the Ds bit
* The Q bit may be stale in the CSA

This change fixes the first issue by clearing the relevant bits from
the MFC_CNTL value in the CSA before or-ing in the updated status.
Also, we add the Q bit to the updated status.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: fix save of mfc_cntl register

Currently, we can introduce invalid entries into the MFC queues:

1) context starts a DMA

2) context gets scheduled out during a DMA
- kernel saves

[POWERPC] spufs: fix save of mfc_cntl register

Currently, we can introduce invalid entries into the MFC queues:

1) context starts a DMA

2) context gets scheduled out during a DMA
- kernel saves MFC queue to CSA
- kernel saves 0x0 in csa->mfc_control_RW

3) context gets scheduled in
- csa->mfc_control[Q] ('queues empty') isn't set, so DMA queues are
restored from the CSA

4) context's DMA is completed

5) context gets scheduled out again, no DMA occuring this time
- kernel sees that MFC_CNTL[Q] ('queues empty') is set, so doesn't
touch saved queue data in CSA
- kernel saves 0x0 in csa->mfc_control_RW

6) context gets scheduled in
- csa->mfc_control[Q] ('queues empty') isn't set (we saved is as 0!),
so DMA queues are restored from the CSA

In this last restore, we've restored the queue status from step 2,
which are now invalid.

This change makes save_mfc_cntl() closer to the save/restore sequence,
as specified in the CBE handbook.

With changes from Luke Browning.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: don't touch suspend bits when purging DMA queue

When we issue a MFC purge request, we may inadvertantly clear the
suspended status.

This change adds the MFC_CNTL_SUSPEND_MASK when

[POWERPC] spufs: don't touch suspend bits when purging DMA queue

When we issue a MFC purge request, we may inadvertantly clear the
suspended status.

This change adds the MFC_CNTL_SUSPEND_MASK when we issue a purge
request, so that the suspend bit is masked out.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: save MFC command channel before purging MFC queue

During the context save process, we currently save the MFC command
channel after purging the MFC queues. This causes a systemsim wa

[POWERPC] spufs: save MFC command channel before purging MFC queue

During the context save process, we currently save the MFC command
channel after purging the MFC queues. This causes a systemsim warning,
as the command channel may be in an unknown state after the purge.

This change does the save before purging the MFC queues.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: synchronize IRQ when disabling

There is a small race between the context save procedure
and the SPU interrupt handling, where we expect all interrupt
processing to have finished aft

[POWERPC] spufs: synchronize IRQ when disabling

There is a small race between the context save procedure
and the SPU interrupt handling, where we expect all interrupt
processing to have finished after disabling them, while
an interrupt is still being processed on another CPU.

The obvious fix is to call synchronize_irq() after disabling
the interrupts at the start of the context save procedure
to make sure we never access the SPU any more during an
ongoing save or even after that.

Thanks to Benjamin Herrenschmidt for pointing this out.

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] cell: fix spurious false return from spu_trap_data_{map,seg}

At present, the __spufs_trap_data_map and __spu_trap_data_seq functions
exit if spu->flags has the SPU_CONTEXT_SWITCH_ACTIVE se

[POWERPC] cell: fix spurious false return from spu_trap_data_{map,seg}

At present, the __spufs_trap_data_map and __spu_trap_data_seq functions
exit if spu->flags has the SPU_CONTEXT_SWITCH_ACTIVE set. This was
resulting in suprious returns from these functions, as they may be
legitimately called when we have this bit set.

We only use it in these two sanity checks, so this change removes the
flag completely. This fixes hangs in the page-fault path of SPE apps.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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[POWERPC] spufs: don't set reserved bits in spu interrupt status

This changes the spu context switch code to not write to reserved bits
of spu interrupt status register.
The architecture book says t

[POWERPC] spufs: don't set reserved bits in spu interrupt status

This changes the spu context switch code to not write to reserved bits
of spu interrupt status register.
The architecture book says the reserved fields should be set to zero.

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

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[POWERPC] spufs: rework class 0 and 1 interrupt handling

Based on original patches from
Arnd Bergmann <arnd.bergman@de.ibm.com>; and
Luke Browning <lukebr@linux.vnet.ibm.com>

Currently, spu conte

[POWERPC] spufs: rework class 0 and 1 interrupt handling

Based on original patches from
Arnd Bergmann <arnd.bergman@de.ibm.com>; and
Luke Browning <lukebr@linux.vnet.ibm.com>

Currently, spu contexts need to be loaded to the SPU in order to take
class 0 and class 1 exceptions.

This change makes the actual interrupt-handlers much simpler (ie,
set the exception information in the context save area), and defers the
handling code to the spufs_handle_class[01] functions, called from
spufs_run_spu.

This should improve the concurrency of the spu scheduling leading to
greater SPU utilization when SPUs are overcommited.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

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[POWERPC] spufs: move fault, lscsa_alloc and switch code to spufs module

Currently, part of the spufs code (switch.o, lscsa_alloc.o and fault.o)
is compiled directly into the kernel.

This change mo

[POWERPC] spufs: move fault, lscsa_alloc and switch code to spufs module

Currently, part of the spufs code (switch.o, lscsa_alloc.o and fault.o)
is compiled directly into the kernel.

This change moves these components of spufs into the kernel.

The lscsa and switch objects are fairly straightforward to move in.

For the fault.o module, we split the fault-handling code into two
parts: a/p/p/c/spu_fault.c and a/p/p/c/spufs/fault.c. The former is for
the in-kernel spu_handle_mm_fault function, and we move the rest of the
fault-handling code into spufs.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

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[POWERPC] cell: handle SPE kernel mappings that cross segment boundaries

Currently, we have a possibilty that the SLBs setup during context
switch don't cover the entirety of the necessary lscsa and

[POWERPC] cell: handle SPE kernel mappings that cross segment boundaries

Currently, we have a possibilty that the SLBs setup during context
switch don't cover the entirety of the necessary lscsa and code
regions, if these regions cross a segment boundary.

This change checks the start and end of each region, and inserts a SLB
entry for each, if unique. We also remove the assumption that the
spu_save_code and spu_restore_code reside in the same segment, by using
the specific code array for save and restore.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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[POWERPC] cell: handle kernel SLB setup in spu_base.c

Currently, the SPU context switch code (spufs/switch.c) sets up the
SPU's SLBs directly, which requires some low-level mm stuff.

This change mo

[POWERPC] cell: handle kernel SLB setup in spu_base.c

Currently, the SPU context switch code (spufs/switch.c) sets up the
SPU's SLBs directly, which requires some low-level mm stuff.

This change moves the kernel SLB setup to spu_base.c, by exposing
a function spu_setup_kernel_slbs() to do this setup. This allows us
to remove the low-level mm code from switch.c, making it possible
to later move switch.c to the spufs module.

Also, add a struct spu_slb for the cases where we need to deal with
SLB entries.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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[POWERPC] Use 1TB segments

This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T)

[POWERPC] Use 1TB segments

This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).

We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.

We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments. That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.

Parts of this patch were originally written by Ben Herrenschmidt.

Signed-off-by: Paul Mackerras <paulus@samba.org>

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[POWERPC] spufs: Fix restore_decr_wrapped() to match CBE Handbook

Based on an original patch from Masato Noguchi
<Masato.Noguchi@jp.sony.com>.

We're currently not restoring the SPE decrementer as s

[POWERPC] spufs: Fix restore_decr_wrapped() to match CBE Handbook

Based on an original patch from Masato Noguchi
<Masato.Noguchi@jp.sony.com>.

We're currently not restoring the SPE decrementer as specified by the
CBE handbook. This change fixes our implementation to match, and makes
the function read more like the docs.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

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[POWERPC] spufs: Remove spu_harvest

Based on an initial patch from Sebastian Siewior
<sebastian@breakpoint.cc>

spu_harvest isn't used, remove it.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-

[POWERPC] spufs: Remove spu_harvest

Based on an initial patch from Sebastian Siewior
<sebastian@breakpoint.cc>

spu_harvest isn't used, remove it.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

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[CELL] spufs: dont halt decrementer at restore step 47

No need to halt the SPE decrementer at context restore step 47, it will
be done in step 7.

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.so

[CELL] spufs: dont halt decrementer at restore step 47

No need to halt the SPE decrementer at context restore step 47, it will
be done in step 7.

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

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[CELL] spufs: limit saving MFC_CNTL bits

At save step 8, the mfc control register in the CSA should be written
_only_ with Sc and Sm bits (at least MFC_CNTL[Dh] should be set to 0)

Signed-off-by: M

[CELL] spufs: limit saving MFC_CNTL bits

At save step 8, the mfc control register in the CSA should be written
_only_ with Sc and Sm bits (at least MFC_CNTL[Dh] should be set to 0)

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

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[CELL] spufs: fix decr_status meanings

The decr_status in the LSCSA is confusedly used as two meanings:
* SPU decrementer was running
* SPU decrementer was wrapped as a result of adjust
and the co

[CELL] spufs: fix decr_status meanings

The decr_status in the LSCSA is confusedly used as two meanings:
* SPU decrementer was running
* SPU decrementer was wrapped as a result of adjust
and the code to set decr_status is missing.

This patch fixes these problems by using the decr_status argument as a
set of flags. This requires a rebuild of the shipped spu_restore code.

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

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[CELL] spufs: remove needless context save/restore code

The following steps are not needed in the SPE context save/restore
paths:

Save Step 12: save_mfc_decr()
save suspend_time to CSA (It will b

[CELL] spufs: remove needless context save/restore code

The following steps are not needed in the SPE context save/restore
paths:

Save Step 12: save_mfc_decr()
save suspend_time to CSA (It will be done by step 14)
save ch 7 (decrementer value will be saved in LSCSA by spe-side step 10)

Restore Step 59: restore_ch_part1()
restore ch 1 (it will be done by spe-side step 15)

This change removes the unnecessary steps.

Signed-off-by: Masato Noguchi <Masato.Noguchi@jp.sony.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

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