linux-stable.git/arch/mips/kernel/pm-cps.c, branch linux-rolling-stable

MIPS: CPS: Introduce struct cluster_boot_config

2025-02-21T09:19:34+00:00

In preparation for supporting multi-cluster systems, introduce a struct
cluster_boot_config as an extra layer in the boot configuration
maintained by the MIPS Coherent Processing System (CPS) SMP
implementation. For now only one struct cluster_boot_config will be
allocated & we'll simply defererence its core_config field to find the
struct core_boot_config array which can be used to boot as usual.

Signed-off-by: Paul Burton 
Signed-off-by: Dragan Mladjenovic 
Signed-off-by: Aleksandar Rikalo 
Tested-by: Serge Semin 
Tested-by: Gregory CLEMENT 
Signed-off-by: Thomas Bogendoerfer

MIPS: pm-cps: Use per-CPU variables as per-CPU, not per-core

2025-02-21T09:19:30+00:00

The pm-cps code has up until now used per-CPU variables indexed by core,
rather than CPU number, in order to share data amongst sibling CPUs (ie.
VPs/threads in a core). This works fine for single cluster systems, but
with multi-cluster systems a core number is no longer unique in the
system, leading to sharing between CPUs that are not actually siblings.

Avoid this issue by using per-CPU variables as they are more generally
used - ie. access them using CPU numbers rather than core numbers.
Sharing between siblings is then accomplished by:
 - Assigning the same pointer to entries for each sibling CPU for the
   nc_asm_enter & ready_count variables, which allow this by virtue of
   being per-CPU pointers.

 - Indexing by the first CPU set in a CPUs cpu_sibling_map in the case
   of pm_barrier, for which we can't use the previous approach because
   the per-CPU variable is not a pointer.

Signed-off-by: Paul Burton 
Signed-off-by: Dragan Mladjenovic 
Signed-off-by: Aleksandar Rikalo 
Tested-by: Serge Semin 
Tested-by: Gregory CLEMENT 
Signed-off-by: Thomas Bogendoerfer

MIPS: pm-cps: Use GPR number macros

2024-02-20T11:41:52+00:00

Use GPR number macros in uasm code generation parts to
reduce code duplication.

There are functional change due to difference in register
symbolic names between OABI and NABI, while existing code
is only using definitions from OABI.

Code pieces are carefully inspected to ensure register
usages are safe on NABI as well.

We changed register allocation of r_pcohctl from T7 to T8
as T7 is not available on NABI and we just want a caller
saved scratch register here.

Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer

MIPS: barrier: Add __SYNC() infrastructure

2019-10-07T16:42:17+00:00

Introduce an asm/sync.h header which provides infrastructure that can be
used to generate sync instructions of various types, and for various
reasons. For example if we need a sync instruction that provides a full
completion barrier but only on systems which have weak memory ordering,
we can generate the appropriate assembly code using:

  __SYNC(full, weak_ordering)

When the kernel is configured to run on systems with weak memory
ordering (ie. CONFIG_WEAK_ORDERING is selected) we'll emit a sync
instruction. When the kernel is configured to run on systems with strong
memory ordering (ie. CONFIG_WEAK_ORDERING is not selected) we'll emit
nothing. The caller doesn't need to know which happened - it simply says
what it needs & when, with no concern for checking the kernel
configuration.

There are some scenarios in which we may want to emit code only when we
*didn't* emit a sync instruction. For example, some Loongson3 CPUs
suffer from a bug that requires us to emit a sync instruction prior to
each ll instruction (enabled by CONFIG_CPU_LOONGSON3_WORKAROUNDS). In
cases where this bug workaround is enabled, it's wasteful to then have
more generic code emit another sync instruction to provide barriers we
need in general. A __SYNC_ELSE() macro allows for this, providing an
extra argument that contains code to be assembled only in cases where
the sync instruction was not emitted. For example if we have a scenario
in which we generally want to emit a release barrier but for affected
Loongson3 configurations upgrade that to a full completion barrier, we
can do that like so:

  __SYNC_ELSE(full, loongson3_war, __SYNC(rl, always))

The assembly generated by these macros can be used either as inline
assembly or in assembly source files.

Differing types of sync as provided by MIPSr6 are defined, but currently
they all generate a full completion barrier except in kernels configured
for Cavium Octeon systems. There the wmb sync-type is used, and rmb
syncs are omitted, as has been the case since commit 6b07d38aaa52
("MIPS: Octeon: Use optimized memory barrier primitives."). Using
__SYNC() with the wmb or rmb types will abstract away the Octeon
specific behavior and allow us to later clean up asm/barrier.h code that
currently includes a plethora of #ifdef's.

Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen 
Cc: Jiaxun Yang 
Cc: linux-kernel@vger.kernel.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

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 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

MIPS: pm-cps: Block system suspend when a JTAG probe is present

2018-03-09T13:53:26+00:00

If a JTAG probe is connected to a MIPS cluster, then the CPC detects it
and latches the CPC.STAT_CONF.EJTAG_PROBE bit to 1. While set,
attempting to send a power-down command to a core will be blocked, and
the CPC will instead send the core to clock-off state. This can
interfere with systems fully entering a low power state where all cores,
CM, GIC, etc are powered down.

Detect that a JTAG probe is / has been connected to the cluster and
block the suspend attempt.

Attempting to suspend the system while a JTAG probe is connected now
yields:
 # echo mem > /sys/power/state
 [   11.654000] PM: Syncing filesystems ... done.
 [   11.658000] JTAG probe is connected - abort suspend
 -sh: echo: write error: Operation not permitted
 #

To restore suspend, the JTAG probe should be disconnected or put into
quiescent state. Platform code can then clear the
CPC.STAT_CONF.EJTAG_PROBE bit.

Reported-by: Ed Blake 
Signed-off-by: Matt Redfearn 
Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18641/
Signed-off-by: James Hogan

Merge branch 'linus' into locking/core, to resolve conflicts

2017-11-07T09:32:44+00:00

Conflicts:
	include/linux/compiler-clang.h
	include/linux/compiler-gcc.h
	include/linux/compiler-intel.h
	include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar

Update MIPS email addresses

2017-11-03T16:02:30+00:00

MIPS will soon not be a part of Imagination Technologies, and as such
many @imgtec.com email addresses will no longer be valid. This patch
updates the addresses for those who:

 - Have 10 or more patches in mainline authored using an @imgtec.com
   email address, or any patches dated within the past year.

 - Are still with Imagination but leaving as part of the MIPS business
   unit, as determined from an internal email address list.

 - Haven't already updated their email address (ie. JamesH) or expressed
   a desire to be excluded (ie. Maciej).

 - Acked v2 or earlier of this patch, which leaves Deng-Cheng, Matt &
   myself.

New addresses are of the form firstname.lastname@mips.com, and all
verified against an internal email address list.  An entry is added to
.mailmap for each person such that get_maintainer.pl will report the new
addresses rather than @imgtec.com addresses which will soon be dead.

Instances of the affected addresses throughout the tree are then
mechanically replaced with the new @mips.com address.

Signed-off-by: Paul Burton 
Cc: Deng-Cheng Zhu 
Cc: Deng-Cheng Zhu 
Acked-by: Dengcheng Zhu 
Cc: Matt Redfearn 
Cc: Matt Redfearn 
Acked-by: Matt Redfearn 
Cc: Andrew Morton 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Signed-off-by: Linus Torvalds

locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

2017-10-25T09:01:08+00:00

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland 
Signed-off-by: Paul E. McKenney 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

MIPS: CPS: Have asm/mips-cps.h include CM & CPC headers

2017-08-29T22:57:27+00:00

With Coherence Manager (CM) 3.5 information about the topology of the
system, which has previously only been available through & accessed from
the CM, is now also provided by the Cluster Power Controller (CPC). This
includes a new CPC_CONFIG register mirroring GCR_CONFIG, and similarly a
new CPC_Cx_CONFIG register mirroring GCR_Cx_CONFIG.

In preparation for adjusting functions such as mips_cm_numcores(), which
have previously only needed to access the CM, to also access the CPC
this patch modifies the way we use the various CPS headers. Rather than
having users include asm/mips-cm.h or asm/mips-cpc.h individually we
instead have users include asm/mips-cps.h which in turn includes
asm/mips-cm.h & asm/mips-cpc.h. This means that users will gain access
to both CM & CPC registers by including one header, and most importantly
it makes asm/mips-cps.h an ideal location for helper functions which
need to access the various components of the CPS.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17015/
Patchwork: https://patchwork.linux-mips.org/patch/17217/
Signed-off-by: Ralf Baechle