No current systems implementing MSA include support for vector register
partitioning which makes it somewhat difficult to implement support for
it in the kernel. Thus for the moment the kernel includes no such
support. However if the kernel were to be run on a system which
implemented register partitioning then it would not function correctly,
mishandling MSA disabled exceptions. Print a warning if run on a system
with vector register partitioning implemented to indicate this problem
should it occur.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6494/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch adds a simple handler for MSA FP exceptions which delivers a
SIGFPE to the running task. In the future it should probably be extended
to re-execute the instruction with the MSACSR.NX bit set in order to
generate results for any elements which did not cause an exception
before delivering the SIGFPE signal.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6432/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch adds support for context switching the MSA vector registers.
These 128 bit vector registers are aliased with the FP registers - an
FP register accesses the least significant bits of the vector register
with which it is aliased (ie. the register with the same index). Due to
both this & the requirement that the scalar FPU must be 64-bit (FR=1) if
enabled at the same time as MSA the kernel will enable MSA & scalar FP
at the same time for tasks which use MSA. If we restore the MSA vector
context then we might as well enable the scalar FPU since the reason it
was left disabled was to allow for lazy FP context restoring - but we
just restored the FP context as it's a subset of the vector context. If
we restore the FP context and have previously used MSA then we have to
restore the whole vector context anyway (see comment in
enable_restore_fp_context for details) so similarly we might as well
enable MSA.

Thus if a task does not use MSA then it will continue to behave as
without this patch - the scalar FP context will be saved & restored as
usual. But if a task executes an MSA instruction then it will save &
restore the vector context forever more.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6431/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch adds support for probing the MSAP bit within the Config3
register in order to detect the presence of the MSA ASE. Presence of the
ASE will be indicated in /proc/cpuinfo. The value of the MSA
implementation register will be displayed at boot to aid debugging and
verification of a correct setup, as is done for the FPU.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6430/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch introduces definitions for the MSA control registers and
functions which allow access to both the control & vector registers. If
the toolchain being used to build the kernel includes support for MSA
then this patch will make use of that support & use MSA instructions
directly. However toolchain support for MSA is very new & far from a
point where it can be reasonably expected that everyone building the
kernel uses a toolchain with support. Thus fallbacks using .word
assembler directives are also provided for now as a temporary measure.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6429/
Patchwork: https://patchwork.linux-mips.org/patch/6607/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

When saving or restoring scalar FP context we want to access the least
significant 64 bits of each FP register. When the FP registers are 64
bits wide that is trivially the start of the registers value in memory.
However when the FP registers are wider this equivalence will no longer
be true for big endian systems. Define a new set of offset macros for
the least significant 64 bits of each saved FP register within thread
context, and make use of them when saving and restoring scalar FP
context.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6428/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

When we want to access 64-bit FP register values we can only treat
consecutive registers as being consecutive in memory when the width of
an FP register equals 64 bits. This assumption will not remain true once
MSA support is introduced, so provide a code path which copies each 64
bit FP register value in turn when the width of an FP register differs
from 64 bits.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6427/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This code assumed that saved FP registers are 64 bits wide, an
assumption which will no longer be true once MSA is introduced. This
patch modifies the code to copy the lower 64 bits of each register in
turn, which is safe for any FP register width >= 64 bits.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6425/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The upper bits of an FP register are architecturally defined as
unpredictable following an instructions which only writes the lower
bits. The prior behaviour of the kernel is to leave them unmodified.
This patch modifies that to clear the upper bits to zero. This is what
the MSA architecture reference manual specifies should happen for its
wider registers and is still permissible for scalar FP instructions
given the bits unpredictability there.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: sergei.shtylyov@cogentembedded.com
Patchwork: https://patchwork.linux-mips.org/patch/6435/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

NUM_FPU_REGS just makes it clearer what's going on, rather than the
magic hard coded 32.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6424/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

When a task which has used the FPU at some point in its past takes a
signal the kernel would previously always require the task to take
ownership of the FPU whilst setting up or restoring from the sigcontext.
That means that if the task has not used the FPU within this timeslice
then the kernel would enable the FPU, restore the task's FP context into
FPU registers and then save them into the sigcontext. This seems
inefficient, and if the signal handler doesn't use FP then enabling the
FPU & the extra memory accesses are entirely wasted work.

This patch modifies the sigcontext setup & restore code to copy directly
between the tasks saved FP context & the sigcontext for any tasks which
have used FP in the past but are not currently the FPU owner (ie. have
not used FP in this timeslice).
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6423/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

These functions aren't directly related to the FPU emulator at all, they
simply copy between a thread's saved context & a sigcontext. Thus move
them to the appropriate signal files & rename them accordingly. This
makes it clearer that the functions don't require the FPU emulator in
any way.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6422/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The hard-coded offsets mentioned in this comment seem to not exist
anymore, so remove mention of them from the comment.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6421/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch replaces the fpureg_t typedef with a "union fpureg" enabling
easier access to 32 & 64 bit values. This allows the access macros used
in cp1emu.c to be simplified somewhat. It will also make it easier to
expand the width of the FP registers as will be done in a future
patch in order to support the 128 bit registers introduced with MSA.

No behavioural change is intended by this patch.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6532/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6401/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

When userland uses syscall() to perform an indirect system call
the actually system call that needs to be checked by the filter
is on the first argument. The kernel code needs to handle this case
by looking at the original syscall number in v0 and if it's
NR_syscall, then it needs to examine the first argument to
identify the real system call that will be executed.
Similarly, we need to 'virtually' shift the syscall() arguments
so the syscall_get_arguments() function can fetch the correct
arguments for the indirect system call.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6404/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6399/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS now has the infrastructure for dynamic seccomp-bpf
filtering
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6400/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Add _TIF_SECCOMP flag to _TIF_WORK_SYSCALL_ENTRY to indicate
that the system call needs to be checked against a seccomp filter.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6405/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This effectively renames __syscall_get_arch to syscall_get_arch
and implements a compatible interface for the seccomp API.
The seccomp code (kernel/seccomp.c) expects a syscall_get_arch
function to be defined for every architecture, so we drop
the leading underscores from the existing function.

This also makes use of the 'task' argument to determine the type
the process instead of assuming the process has the same
characteristics as the kernel it's running on.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6398/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The syscall_rollback function is used by seccomp-bpf but it was never
added for MIPS. It doesn't need to do anything as none of the registers
are clobbered if the system call has been denied by the seccomp filter.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6403/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

CONFIG_MIPS_CPS is a better option for systems where it is supported,
which as far as I am aware should be all systems where CONFIG_MIPS_CMP
could provide any value (ie. where there are multiple cores for YAMON to
bring up). This option is therefore deprecated, and marked as such. It
is left intact for the time being in order to provide a fallback should
someone find a system where CONFIG_MIPS_CPS will not function (ie. where
the reset vector cannot be moved), and should be removed entirely in the
future assuming that does not happen.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6369/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Commit f55afb0969cc "MIPS: Clean up MIPS MT and CMP configuration
options." introduced a dependency upon MIPS_MT_SMP (ie. SMVP) for the
MIPS_CMP (ie. CMP framework support) Kconfig option. It did not specify
why, and that dependency is bogus. It is perfectly valid to have a
multi-core system with the YAMON bootloader but without MT support -
an example of this would be any multi-core proAptiv bitstream running on
a Malta. Forcing MT support to be enabled in a kernel for such a system
is incorrect. I suspect that the dependency was actually meant to
reflect the fact that YAMON will only bind 1 TC per VPE on an MT system,
and only describe those 1:1 TC:VPE pairs as CPUs through the AMON
interface. Thus an SMTC kernel makes little sense on a system using
MIPS_CMP, and the Kconfig dependencies should reflect that rather than
introducing the bogus SMVP dependency.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6368/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The prior help text introduced in commit f55afb0969cc "MIPS: Clean up
MIPS MT and CMP configuration options." reads as though this option
enables the kernel to make use of the CM hardware, which is not true.
What it actually does is allow the kernel to interact with the YAMON
bootloader which actually interacts with the CM hardware to bring up
secondary cores. Re-introduce the word "framework" which that commit
removed to avoid misleading people.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6367/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This header was used only by Malta but is used no longer. Remove it. It
was also included unnecessarily in irq-gic.c, so that include is also
removed.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6366/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch simply attempts to register the MIPS Coherent Processing
System SMP implementation when it is enabled. If registering that fails
for some reason (like the Kconfig option being disabled or a lack of
hardware support) then we fall back to the same SMP implementations as
before.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6365/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

When CPC support is compiled into the kernel (ie. CONFIG_MIPS_CPC=y),
probe the CPC on boot for Malta in order to allow any users of the CPC
to detect its presence & function correctly.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6363/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Remove the Malta-specific CM probe code and instead make use of the
newly added generic CM code.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6364/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch introduces a new SMP implementation for systems implementing
the MIPS Coherent Processing System architecture. The kernel will make
use of the Coherence Manager, Cluster Power Controller & Global
Interrupt Controller in order to detect, bring up & make use of other
cores in the system. SMTC is not supported, so only a single TC per VPE
in the system is used. That is, this option enables an SMVP style setup
but across multiple cores.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6362/
Patchwork: https://patchwork.linux-mips.org/patch/6611/
Patchwork: https://patchwork.linux-mips.org/patch/6651/
Patchwork: https://patchwork.linux-mips.org/patch/6652/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The vpe_id field of struct cpuinfo_mips is only present when one of
CONFIG_MIPS_MT_{SMP,SMTC} is enabled. That means that any code accessing
which may compile without MT is currently forced to use an #ifdef.
Instead this patch provides an accessor macro, #ifdef'd appropriately
to prevent further #ifdef's elsewhere.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6646/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch introduces code to probe for a MIPS Cluster Power Controller
& accessor functions to allow for easy register access. This support
code will be used by a subsequent patch.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6361/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The kernel currently only probes for a MIPS Coherence Manager in the
Malta interrupt code in order to detect & enable the GIC. However CM is
not Malta-specific, so this should really be more generic. This patch
introduces some non-Malta-specific code which probes for a CM and
performs some basic initialisation.

A new header, with temporarily duplicated register definitions, is
introduced in order to:

  1) Allow the new definitions to be correct with regards to the
     CM documentation, as many of those in gcmpregs.h aren't.

  2) Allow switching away from the REG() macro used via a few layers of
     nested macros in order to access registers in gcmpregs.h. This
     patch instead introduced accessor functions akin to the
     {read,write}_c0_* functions used for cop0 registers.

  3) Allow users of the CM to be migrated one by one.

  4) Switch from the name 'GCMP' to 'CM' since the Coherence Manager is
     what this code is actually dealing with.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6360/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The GIC IPI functions aren't necessarily specific to the "CMP
framework" SMP implementation, and will be used elsewhere in a
subsequent commit. This patch adds cleaned up GIC IPI functions to a
separate file which is compiled when a new CONFIG_MIPS_GIC_IPI Kconfig
symbol is selected, and selects that symbol for CONFIG_MIPS_CMP.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6359/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This patch adds a simple macro to wrap the ext instruction which was
introduced with MIPSR2, and fall back to a shift & and pair for
pre-MIPSR2 CPUs. This will be used in a subsequent patch.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6358/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The gic.h header uses bitmaps and NR_CPUS, and should therefore include
linux/bitmap.h and linux/threads.h. This is in preparation for use of
this header in a subsequent commit from a C file which doesn't already
include those headers.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6357/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The CMGCRBase register is defined by the PRA specification as an optional
register which indicates the physical base of the MIPS Coherence Manager
Global Control Register block. This patch simply adds a definition for
the base address field within the register, along with an accessor
function for reading the register.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6356/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

These fields will be used from assembly code in a subsequent commit, and
defining the size & offset of each field makes that use easier.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6355/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The 1074K is a multiprocessing coherent processing system (CPS) based
on modified 74K cores. This patch makes the 1074K an actual unique
CPU type, instead of a 74K derivative, which it is not.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6389/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The *Aptiv cores can use the CONF7/IAR bit to detect if the core
has hardware support to remove instruction cache aliasing.

This also defines the CONF7/AR bit in order to avoid using
the '16' magic number.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6499/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>