We currently have __ioread32_copy, __iowrite32_copy & __iowrite64_copy
helpers in lib/iomap_copy.c. This patch adds __ioread64_copy to round
out the set, allowing copies from I/O memory using 32 or 64 bit reads.
[ralf@linux-mips.org: Changed to move all the code of this patch to be
applied to arch/mips temporarily.]
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17025/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch introduces a new header providing accessor functions for the
MIPS Global Interrupt Controller (GIC) mirroring those provided for the
other 2 components of the MIPS Coherent Processing System (CPS) - the
Coherence Manager (CM) & Cluster Power Controller (CPC).
This header makes use of the new standardised CPS accessor macros where
possible, but does require some custom accessors for cases where we have
either a bit or a register per interrupt.
A major advantage of this over the existing
include/linux/irqchip/mips-gic.h definitions is that code performing
accesses can become much simpler, for example this:
gic_update_bits(GIC_REG(SHARED, GIC_SH_SET_TRIGGER) +
GIC_INTR_OFS(intr), 1ul << GIC_INTR_BIT(intr),
(unsigned long)trig << GIC_INTR_BIT(intr));
...can become simply:
change_gic_trig(intr, trig);
The accessors handle 32 vs 64 bit in the same way as for CM & CPC code,
which means that GIC code will also not need to worry about the access
size in most cases. They are also accessible outside of
drivers/irqchip/irq-mips-gic.c which will allow for simplification in
the use of the non-interrupt portions of the GIC (eg. counters) which
currently require the interrupt controller driver to expose helper
functions for access.
This patch doesn't change any existing code over to use the new
accessors yet, since a wholesale change would be invasive & difficult to
review. Instead follow-on patches will convert code piecemeal to use
this new header. The one change to existing code is to rename gic_base
to mips_gic_base & make it global, in order to fit in with the naming
expected by the standardised CPS accessor macros.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17020/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Modify the functions we use to read information about the topology of
the system (the number of cores, VPs & IOCUs that it contains) in order
to take into account multiple clusters, and provide a new function to
determine the number of clusters in the system.
Users of these functions are modified only such that they continue to
build successfully - having them actually handle multiple clusters is
left to further patches.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17016/
Patchwork: https://patchwork.linux-mips.org/patch/17218/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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 <paul.burton@imgtec.com>
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 <ralf@linux-mips.org>
Allow the boot_secondary SMP op to return an error to __cpu_up(), which
will in turn return it to its caller.
This will allow SMP implementations to return errors quickly in cases
they they know have failed, rather than relying upon __cpu_up()
eventually timing out waiting for the cpu_running completion.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17014/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
With CM >= 3.5 we have the notion of multiple clusters & can access
their CM, CPC & GIC registers via the apporpriate redirect/other
register blocks. In order to allow for this introduce cluster & block
arguments to mips_cm_lock_other() which configures the redirect/other
region to point at the appropriate cluster, core, VP & register block.
Since we now have 4 arguments to mips_cm_lock_other() & a common use is
likely to be to target the cluster, core & VP corresponding to a
particular Linux CPU number we also add a new mips_cm_lock_other_cpu()
helper function which handles that without the caller needing to
manually pull out the cluster, core & VP numbers.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17013/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Introduce cpu_cluster() & cpu_set_cluster() accessor functions in the
same vein as cpu_core(), cpu_vpe_id() & their set variants. These will
be used in further patches to allow users to get or set a CPUs cluster
number.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17012/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Up until now we have open-coded checks for whether CPUs are siblings,
with slight variations on whether we consider the package ID or not.
This will only get more complex when we introduce cluster support, so in
preparation for that this patch introduces a cpus_are_siblings()
function which can be used to check whether or not 2 CPUs are siblings
in a consistent manner.
By checking globalnumber with the VP ID masked out this also has the
neat side effect of being ready for multi-cluster systems already.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17011/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch modifies the way we store core & VP IDs such that we store
them in a single 32 bit integer whose format matches that of the MIPSr6
GlobalNumber register. Whereas we have previously stored core & VP IDs
in separate fields, storing them in a single GlobalNumber-like field:
1) Reduces the size of struct cpuinfo_mips by 4 bytes, and will allow
it to not grow when cluster support is added.
2) Gives us a natural place to store cluster number, which matches up
with what the architecture provides.
3) Will be useful in the future as a parameter to the MIPSr6 GINVI
instruction to specify a target CPU whose icache that instruction
should operate on.
The cpu_set*() accessor functions are moved out of the asm/cpu-info.h
header in order to allow them to use the WARN_ON macro, which is
unusable in asm/cpu-info.h due to include ordering.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17010/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
We currently have fields in struct cpuinfo_mips for the core & VP(E) ID
of a particular CPU, and various pieces of code directly access those
fields. This patch abstracts such access by introducing accessor
functions cpu_core(), cpu_set_core(), cpu_vpe_id() & cpu_set_vpe_id()
and having code that needs to access these values call those functions
rather than directly accessing the struct cpuinfo_mips fields. This
prepares us for changes to the way in which those values are stored in
later patches.
The cpu_vpe_id() function is introduced even though we already had a
cpu_vpe_id() macro for a couple of reasons:
1) It's more consistent with the core, and future cluster, accessors.
2) It ensures a sensible return type without explicit casts.
3) It's generally preferable to use functions rather than macros.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17009/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPSr6 introduces a GlobalNumber register, which is required when VPs
are implemented (ie. when multi-threading is supported) but otherwise
optional. The register contains sufficient information to uniquely
identify a VP within a system using its cluster number, core number & VP
ID.
In preparation for using this register & its fields, introduce an
accessor macro for it & define its various bits with the typical style
preprocessor macros.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17007/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Introduce definitions & accessors for a selection of Coherence Manager
(CM) & Cluster Power Controller (CPC) registers that are new with CM
v3.5 & the MIPS I6500. These are primarily registers that will be used
in supporting multiple CPU clusters.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17006/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
For read-write registers introduce accessor functions that simplify the
task of modifying a subset of bits within the register. set_* functions
set bits to 1, clear_* functions clear bits to 0 & change_* functions
set bits specified in a mask to an arbitrary value.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17004/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Tidy up asm/mips-cpc.h in a similar way to what "MIPS: CM: Use
BIT/GENMASK for register fields, order & drop shifts" did for
asm/mips-cm.h.
We use BIT() & GENMASK() to simplify the definition of register fields,
drop the _SHF definitions since that information can be found in the
_MSK ones, and then drop the _MSK suffix.
Fields definitions are moved to be next to the appropriate register
definition, making it easier to link the two & keep everything ordered
by register address. Comments are added including the name of each
register & a brief description of its purpose which helps to understand
what registers are for, link them back to hardware documentation or grep
for them.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17003/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Switch the MIPS Cluster Power Controller (CPC) accessor functions to be
generated by the new common Coherent Processing System (CPS) macros
shared with the Coherence Manager (CM).
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17002/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
There's no reason for us not to use BIT() & GENMASK() in asm/mips-cm.h
when declaring macros corresponding to register fields. This patch
modifies our definitions to do so.
The *_SHF definitions are removed entirely - they duplicate information
found in the masks, are infrequently used & can be replaced with use of
__ffs() where needed.
The *_MSK definitions then lose their _MSK suffix which is now somewhat
redundant, and users are modified to match.
The field definitions are moved to follow the appropriate register's
accessor functions, which helps to keep the field definitions in order &
to find the appropriate fields for a given register. Whilst here a
comment is added describing each register & including its name, which is
helpful both for linking the register back to hardware documentation &
for grepping purposes.
This also cleans up a couple of issues that became obvious as a result
of making the changes described above:
- We previously had definitions for GCR_Cx_RESET_EXT_BASE & a phony
copy of that named GCR_RESET_EXT_BASE - a register which does not
exist. The bad definitions were added by commit 497e803ebf ("MIPS:
smp-cps: Ensure secondary cores start with EVA disabled") and made
use of from boot_core(), which is now modified to use the
GCR_Cx_RESET_EXT_BASE definitions.
- We had a typo in CM_GCR_ERROR_CAUSE_ERRINGO_MSK - we now correctly
define this as inFo rather than inGo.
Now that we don't duplicate field information between _SHF & _MSK
definitions, and keep the fields next to the register accessors, it will
be much easier to spot & prevent any similar oddities being introduced
in the future.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17001/
Patchwork: https://patchwork.linux-mips.org/patch/17216/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Some CM registers are always 32 bits, or at least only use bits in the
lower 32 bits of the register. For these registers it is wasteful for us
to generate accessors which bother to check mips_cm_is64 & perform 64
bit accesses.
This patch modifies the accessor generation to take into account the
size of the register, and for 32 bit registers we generate accessors
which only ever perform 32 bit accesses. For 64 bit registers we either
perform a 64 bit access or two 32 bit accesses, depending upon the value
of mips_cm_is64. Doing this saves us ~1.5KiB of code in a generic 64r6el
kernel, and perhaps more importantly simplifies various code paths.
This removes the read64_gcr_* accessors, so mips_cm_error_report() is
modified to stop using them & instead use the regular read_gcr_*
accessors which will return 64 bit values from the 64 bit registers.
The new accessor macros are placed in asm/mips-cps.h such that they can
be shared by CPC & GIC code in later patches.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17000/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
We currently have a mips_cm_base variable which holds the base address
of the Coherence Manager (CM) Global Configuration Registers (GCRs), and
accessor functions which use the GCR in their names. This works fine,
but gets in the way of sharing the code to generate the accessor
functions with other blocks (ie. CPC & GIC) because that code would then
need to separately handle the name of the base address variable & the
name used in the accessor functions.
In order to prepare for sharing the accessor generation code between CM,
CPC & GIC code this patch renames mips_cm_base to mips_gcr_base such
that the "gcr" portion is common to both the base address variable & the
accessor function names.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16999/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add FP emulation debugfs statistics for individual instructions. The
debugfs files that contain counter values are placed in a separate
directory called "instructions". This means that the default path for
these new stat is "/sys/kernel/debug/mips/fpuemustats/instructions".
Each instruction counter is mapped to the debugfs file that has the
same name as instruction name. The lowercase is choosen as more
commonly used case for instruction names.
One example of usage:
mips_host::/sys/kernel/debug/mips/fpuemustats/instructions # grep "" *
The shortened output of this command is:
abs.d:34
abs.s:5711
add.d:10401
add.s:399307
bc1eqz:3199
...
...
...
sub.s:167211
trunc.l.d:375
trunc.l.s:8054
trunc.w.d:421
trunc.w.s:27032
The limitation of this patch is that it handles R6 FP emulation
instructions only. There are altogether 114 handled instructions.
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17145/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add FP emu debugfs counter for branches.
The new counter is displayed the same way as existing counter, and
its default path is /sys/kernel/debug/mips/fpuemustats/.
The limitation of this counter is that it counts only R6 branch
instructions BC1NEZ and BC1EQZ.
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17143/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The fault_addr argument to fpu_emulator_cop1Handler(), fpux_emu() and
cop1Emulate() has up until now been declared as:
void *__user *fault_addr
This is essentially a pointer in user memory which points to a pointer
to void. This is not the intent for our code, which is actually
operating on a pointer to a pointer to void where the pointer to void is
pointing at user memory. ie. the pointer is in kernel memory & points to
user memory.
This mismatch produces a lot of sparse warnings that look like this:
arch/mips/math-emu/cp1emu.c:1485:45:
warning: incorrect type in assignment (different address spaces)
expected void *[noderef] <asn:1><noident>
got unsigned int [noderef] [usertype] <asn:1>*[assigned] va
Fix these by modifying the declaration of the fault_addr argument to:
void __user **fault_addr
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17173/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
No advanced MIPS features for Alchemy.
This patch shaves additional 43kB off the DB1300 kernel
(~0.5% size reduction).
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15286/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Define Cavium Octeon as a CPU that has support for mips32r1, mips32r2 and
mips64r1. This will affect show_cpuinfo() that will now correctly expose
mips32r1, mips32r2 and mips64r1 as supported ISAs.
Signed-off-by: Petar Jovanovic <petar.jovanovic@rt-rk.com>
Reviewed-by: Maciej W. Rozycki <macro@imgtec.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: petar.jovanovic@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15749/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit a7be6e5a7f ("mm: drop useless local parameters of
__register_one_node()") removes the last user of parent_node().
The parent_node() macros in both IP27 and Loongson64 are unnecessary.
Remove it for cleanup.
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16873/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The kernel contains a small amount of incomplete code aimed at
supporting old R6000 CPUs. This is:
- Unused, as no machine selects CONFIG_SYS_HAS_CPU_R6000.
- Broken, since there are glaring errors such as r6000_fpu.S moving
the FCSR register to t1, then ignoring it & instead saving t0 into
struct sigcontext...
- A maintenance headache, since it's code that nobody can test which
nevertheless imposes constraints on code which it shares with other
machines.
Remove this incomplete & broken R6000 CPU support in order to clean up
and in preparation for changes which will no longer need to consider
dragging the pretense of R6000 support along with them.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16236/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
smp_ops providers do not modify their ops structures, so they should be
made const for robustness. Since currently the MIPS kernel is not mapped
with memory protection, this does not in itself provide any security
benefit, but it still makes sense to make this change.
There are also slight code size efficincies from the structure being
made read-only, saving 128 bytes of kernel text on a
pistachio_defconfig.
Before:
text data bss dec hex filename
7187239 1772752 470224 9430215 8fe4c7 vmlinux
After:
text data bss dec hex filename
7187111 1772752 470224 9430087 8fe447 vmlinux
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Doug Ledford <dledford@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Joe Perches <joe@perches.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven J. Hill <steven.hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16784/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
There exist macros to return the cache line size of the L1 dcache and L2
scache but there is currently no macro for the L3 tcache. Add this macro
which will be used by the following patch "MIPS: PCI: Fix
smp_processor_id() in preemptible"
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16871/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit 296e46db00 ("MIPS: Don't unnecessarily include kmalloc.h into
<asm/cache.h>.") claimed that the inclusion of the machine's kmalloc.h
from asm/cache.h is unnecessary, but this is not true.
Without including kmalloc.h we don't get a definition for
ARCH_DMA_MINALIGN, which means we no longer suitably align DMA. Further
to this the definition of ARCH_KMALLOC_MINALIGN provided by linux/slab.h
ends up being set to the alignment of an unsigned long long value rather
than to ARCH_DMA_MINALIGN, which means that buffers allocated using
kmalloc may no longer be safely aligned for use with DMA.
Fix this by re-adding the include of kmalloc.h in asm/cache.h. This
reverts commit 296e46db00 ("MIPS: Don't unnecessarily include
kmalloc.h into <asm/cache.h>.")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 296e46db00 ("MIPS: Don't unnecessarily include kmalloc.h into <asm/cache.h>.")
Cc: linux-mips@linux-mips.org
Cc: stable <stable@vger.kernel.org> # v4.12+
Patchwork: https://patchwork.linux-mips.org/patch/16895/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit "MIPS: Octeon: Remove unused L2C types and macros." broke the
the EDAC driver. Bring back 'cvmx-l2d-defs.h' file and the missing
types for L2C. Fixes: 15f6847923 ("MIPS: Octeon: Remove unused L2C
types and macros.")
Fixes: 15f6847923 ("MIPS: Octeon: Remove unused L2C types and macros.")
Signed-off-by: Steven J. Hill <steven.hill@cavium.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.12+
Patchwork: https://patchwork.linux-mips.org/patch/16906/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Previously, <linux/module.h> was included before ralink_regs.h in all
ralink files - leading to <linux/io.h> being implicitly included.
After commit 26dd3e4ff9 ("MIPS: Audit and remove any unnecessary
uses of module.h") removed the inclusion of module.h from multiple
places, some ralink platforms failed to build with the following error:
In file included from arch/mips/ralink/mt7620.c:17:0:
./arch/mips/include/asm/mach-ralink/ralink_regs.h: In function ‘rt_sysc_w32’:
./arch/mips/include/asm/mach-ralink/ralink_regs.h:38:2: error: implicit declaration of function ‘__raw_writel’ [-Werror=implicit-function-declaration]
__raw_writel(val, rt_sysc_membase + reg);
^
./arch/mips/include/asm/mach-ralink/ralink_regs.h: In function ‘rt_sysc_r32’:
./arch/mips/include/asm/mach-ralink/ralink_regs.h:43:2: error: implicit declaration of function ‘__raw_readl’ [-Werror=implicit-function-declaration]
return __raw_readl(rt_sysc_membase + reg);
Fix this by including <linux/io.h>.
Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Fixes: 26dd3e4ff9 ("MIPS: Audit and remove any unnecessary uses of module.h")
Cc: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> #4.11+
Patchwork: https://patchwork.linux-mips.org/patch/16780/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull uacess-unaligned removal from Al Viro:
"That stuff had just one user, and an exotic one, at that - binfmt_flat
on arm and m68k"
* 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill {__,}{get,put}_user_unaligned()
binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail
Pull MIPS updates from Ralf Baechle:
"Boston platform support:
- Document DT bindings
- Add CLK driver for board clocks
CM:
- Avoid per-core locking with CM3 & higher
- WARN on attempt to lock invalid VP, not BUG
CPS:
- Select CONFIG_SYS_SUPPORTS_SCHED_SMT for MIPSr6
- Prevent multi-core with dcache aliasing
- Handle cores not powering down more gracefully
- Handle spurious VP starts more gracefully
DSP:
- Add lwx & lhx missaligned access support
eBPF:
- Add MIPS support along with many supporting change to add the
required infrastructure
Generic arch code:
- Misc sysmips MIPS_ATOMIC_SET fixes
- Drop duplicate HAVE_SYSCALL_TRACEPOINTS
- Negate error syscall return in trace
- Correct forced syscall errors
- Traced negative syscalls should return -ENOSYS
- Allow samples/bpf/tracex5 to access syscall arguments for sane
traces
- Cleanup from old Kconfig options in defconfigs
- Fix PREF instruction usage by memcpy for MIPS R6
- Fix various special cases in the FPU eulation
- Fix some special cases in MIPS16e2 support
- Fix MIPS I ISA /proc/cpuinfo reporting
- Sort MIPS Kconfig alphabetically
- Fix minimum alignment requirement of IRQ stack as required by
ABI / GCC
- Fix special cases in the module loader
- Perform post-DMA cache flushes on systems with MAARs
- Probe the I6500 CPU
- Cleanup cmpxchg and add support for 1 and 2 byte operations
- Use queued read/write locks (qrwlock)
- Use queued spinlocks (qspinlock)
- Add CPU shared FTLB feature detection
- Handle tlbex-tlbp race condition
- Allow storing pgd in C0_CONTEXT for MIPSr6
- Use current_cpu_type() in m4kc_tlbp_war()
- Support Boston in the generic kernel
Generic platform:
- yamon-dt: Pull YAMON DT shim code out of SEAD-3 board
- yamon-dt: Support > 256MB of RAM
- yamon-dt: Use serial* rather than uart* aliases
- Abstract FDT fixup application
- Set RTC_ALWAYS_BCD to 0
- Add a MAINTAINERS entry
core kernel:
- qspinlock.c: include linux/prefetch.h
Loongson 3:
- Add support
Perf:
- Add I6500 support
SEAD-3:
- Remove GIC timer from DT
- Set interrupt-parent per-device, not at root node
- Fix GIC interrupt specifiers
SMP:
- Skip IPI setup if we only have a single CPU
VDSO:
- Make comment match reality
- Improvements to time code in VDSO"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (86 commits)
locking/qspinlock: Include linux/prefetch.h
MIPS: Fix MIPS I ISA /proc/cpuinfo reporting
MIPS: Fix minimum alignment requirement of IRQ stack
MIPS: generic: Support MIPS Boston development boards
MIPS: DTS: img: Don't attempt to build-in all .dtb files
clk: boston: Add a driver for MIPS Boston board clocks
dt-bindings: Document img,boston-clock binding
MIPS: Traced negative syscalls should return -ENOSYS
MIPS: Correct forced syscall errors
MIPS: Negate error syscall return in trace
MIPS: Drop duplicate HAVE_SYSCALL_TRACEPOINTS select
MIPS16e2: Provide feature overrides for non-MIPS16 systems
MIPS: MIPS16e2: Report ASE presence in /proc/cpuinfo
MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions
MIPS: MIPS16e2: Identify ASE presence
MIPS: VDSO: Fix a mismatch between comment and preprocessor constant
MIPS: VDSO: Add implementation of gettimeofday() fallback
MIPS: VDSO: Add implementation of clock_gettime() fallback
MIPS: VDSO: Fix conversions in do_monotonic()/do_monotonic_coarse()
MIPS: Use current_cpu_type() in m4kc_tlbp_war()
...
Patch series "mm: give __GFP_REPEAT a better semantic".
The main motivation for the change is that the current implementation of
__GFP_REPEAT is not very much useful.
The documentation says:
* __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt
* _might_ fail. This depends upon the particular VM implementation.
It just fails to mention that this is true only for large (costly) high
order which has been the case since the flag was introduced. A similar
semantic would be really helpful for smal orders as well, though,
because we have places where a failure with a specific fallback error
handling is preferred to a potential endless loop inside the page
allocator.
The earlier cleanup dropped __GFP_REPEAT usage for low (!costly) order
users so only those which might use larger orders have stayed. One new
user added in the meantime is addressed in patch 1.
Let's rename the flag to something more verbose and use it for existing
users. Semantic for those will not change. Then implement low
(!costly) orders failure path which is hit after the page allocator is
about to invoke the oom killer. With that we have a good counterpart
for __GFP_NORETRY and finally can tell try as hard as possible without
the OOM killer.
Xfs code already has an existing annotation for allocations which are
allowed to fail and we can trivially map them to the new gfp flag
because it will provide the semantic KM_MAYFAIL wants. Christoph didn't
consider the new flag really necessary but didn't respond to the OOM
killer aspect of the change so I have kept the patch. If this is still
seen as not really needed I can drop the patch.
kvmalloc will allow also !costly high order allocations to retry hard
before falling back to the vmalloc.
drm/i915 asked for the new semantic explicitly.
Memory migration code, especially for the memory hotplug, should back
off rather than invoking the OOM killer as well.
This patch (of 6):
Commit 3377e227af ("MIPS: Add 48-bit VA space (and 4-level page
tables) for 4K pages.") has added a new __GFP_REPEAT user but using this
flag doesn't really make any sense for order-0 request which is the case
here because PUD_ORDER is 0. __GFP_REPEAT has historically effect only
on allocation requests with order > PAGE_ALLOC_COSTLY_ORDER.
This doesn't introduce any functional change. This is a preparatory
patch for later work which renames the flag and redefines its semantic.
Link: http://lkml.kernel.org/r/20170623085345.11304-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit db8466c581 ("MIPS: IRQ Stack: Unwind IRQ stack onto task
stack") erroneously set the initial stack pointer of the IRQ stack to a
value with a 4 byte alignment. The MIPS32 ABI requires that the minimum
stack alignment is 8 byte, and the MIPS64 ABIs(n32/n64) require 16 byte
minimum alignment. Fix IRQ_STACK_START such that it leaves space for the
dummy stack frame (containing interrupted task kernel stack pointer)
while also meeting minimum alignment requirements.
Fixes: db8466c581 ("MIPS: IRQ Stack: Unwind IRQ stack onto task stack")
Reported-by: Darius Ivanauskas <dasilt@yahoo.com>
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16760/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When the system call return value is forced to be an error (for example
due to SECCOMP_RET_ERRNO), syscall_set_return_value() puts the error
code in the return register $v0 and -1 in the error register $a3.
However normally executed system calls put 1 in the error register
rather than -1, so fix syscall_set_return_value() to be consistent with
that.
I don't anticipate that anything would have been broken by this, since
the most natural way to check the error register on MIPS would be a
conditional branch if error register is [not] equal to zero (bnez or
beqz).
Fixes: 1d7bf993e0 ("MIPS: ftrace: Add support for syscall tracepoints.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16652/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Hardcode the absence of the MIPS16e2 ASE for all the systems that do so
for the MIPS16 ASE already, providing for code to be optimized away.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16097/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull user access str* updates from Al Viro:
"uaccess str...() dead code removal"
* 'uaccess.strlen' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
s390 keyboard.c: don't open-code strndup_user()
mips: get rid of unused __strnlen_user()
get rid of unused __strncpy_from_user() instances
kill strlen_user()
Pull misc compat stuff updates from Al Viro:
"This part is basically untangling various compat stuff. Compat
syscalls moved to their native counterparts, getting rid of quite a
bit of double-copying and/or set_fs() uses. A lot of field-by-field
copyin/copyout killed off.
- kernel/compat.c is much closer to containing just the
copyin/copyout of compat structs. Not all compat syscalls are gone
from it yet, but it's getting there.
- ipc/compat_mq.c killed off completely.
- block/compat_ioctl.c cleaned up; floppy compat ioctls moved to
drivers/block/floppy.c where they belong. Yes, there are several
drivers that implement some of the same ioctls. Some are m68k and
one is 32bit-only pmac. drivers/block/floppy.c is the only one in
that bunch that can be built on biarch"
* 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
mqueue: move compat syscalls to native ones
usbdevfs: get rid of field-by-field copyin
compat_hdio_ioctl: get rid of set_fs()
take floppy compat ioctls to sodding floppy.c
ipmi: get rid of field-by-field __get_user()
ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one
rt_sigtimedwait(): move compat to native
select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap()
put_compat_rusage(): switch to copy_to_user()
sigpending(): move compat to native
getrlimit()/setrlimit(): move compat to native
times(2): move compat to native
compat_{get,put}_bitmap(): use unsafe_{get,put}_user()
fb_get_fscreeninfo(): don't bother with do_fb_ioctl()
do_sigaltstack(): lift copying to/from userland into callers
take compat_sys_old_getrlimit() to native syscall
trim __ARCH_WANT_SYS_OLD_GETRLIMIT
Identify the presence of the MIPS16e2 ASE as per the architecture
specification[1], by checking for CP0 Config5.CA2 bit being 1[2].
References:
[1] "MIPS32 Architecture for Programmers: MIPS16e2 Application-Specific
Extension Technical Reference Manual", Imagination Technologies
Ltd., Document Number: MD01172, Revision 01.00, April 26, 2016,
Section 1.2 "Software Detection of the ASE", p. 5
[2] "MIPS32 interAptiv Multiprocessing System Software User's Manual",
Imagination Technologies Ltd., Document Number: MD00904, Revision
02.01, June 15, 2016, Section 2.2.1.6 "Device Configuration 5 --
Config5 (CP0 Register 16, Select 5)", pp. 71-72
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16094/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix incorrect calculation in do_monotonic() and do_monotonic_coarse()
function that in turn caused incorrect values returned by the vdso
version of system call clock_gettime() on mips64 if its system clock
ID parameter was CLOCK_MONOTONIC or CLOCK_MONOTONIC_COARSE.
Consider these variables and their types on mips32 and mips64:
tk->wall_to_monotonic.tv_sec s64, s64 (kernel/vdso.c)
vdso_data.wall_to_mono_sec u32, u32 (kernel/vdso.c)
to_mono_sec u32, u32 (vdso/gettimeofday.c)
ts->tv_sec s32, s64 (vdso/gettimeofday.c)
For mips64 case, u32 vdso_data.wall_to_mono_sec variable is updated
from the 64-bit signed variable tk->wall_to_monotonic.tv_sec
(kernel/vdso.c:76) which is a negative number holding the time passed
from 1970-01-01 to the time boot started. This 64-bit signed value is
currently around 47+ years, in seconds. For instance, let this value
be:
-1489757461
or
11111111111111111111111111111111 10100111001101000001101011101011
By updating 32-bit vdso_data.wall_to_mono_sec variable, we lose upper
32 bits (signed 1's).
to_mono_sec variable is a parameter of do_monotonic() and
do_monotonic_coarse() functions which holds vdso_data.wall_to_mono_sec
value. Its value needs to be added (or subtracted considering it holds
negative value from the tk->wall_to_monotonic.tv_sec) to the current
time passed from 1970-01-01 (ts->tv_sec), which is again something like
47+ years, but increased by the time passed from the boot to the
current time. ts->tv_sec is 32-bit long in case of 32-bit architecture
and 64-bit long in case of 64-bit architecture. Consider the update of
ts->tv_sec (vdso/gettimeofday.c:55 & 167):
ts->tv_sec += to_mono_sec;
mips32 case: This update will be performed correctly, since both
ts->tv_sec and to_mono_sec are 32-bit long and the sign in to_mono_sec
is preserved. Implicit conversion from u32 to s32 will be done
correctly.
mips64 case: This update will be wrong, since the implicit conversion
will not be done correctly. The reason is that the conversion will be
from u32 to s64. This is because to_mono_sec is 32-bit long for both
mips32 and mips64 cases and s64..33 bits of converted to_mono_sec
variable will be zeros.
So, in order to make MIPS64 implementation work properly for
MONOTONIC and MONOTONIC_COARSE clock ids on mips64, the size of
wall_to_mono_sec variable in mips_vdso_data union and respective
parameters in do_monotonic() and do_monotonic_coarse() functions
should be changed from u32 to u64. Because of consistency, this
size change from u32 and u64 is also done for wall_to_mono_nsec
variable and corresponding function parameters.
As far as similar situations for other architectures are concerned,
let's take a look at arm. Arm has two distinct vdso_data structures
for 32-bit & 64-bit cases, and arm's wall_to_mono_sec and
wall_to_mono_nsec are u32 for 32-bit and u64 for 64-bit cases.
On the other hand, MIPS has only one structure (mips_vdso_data),
hence the need for changing the size of above mentioned parameters.
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16638/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Some systems share FTLB RAMs or entries between sibling CPUs (ie.
hardware threads, or VP(E)s, within a core). These properties require
kernel handling in various places. As a start this patch introduces
cpu_has_shared_ftlb_ram & cpu_has_shared_ftlb_entries feature macros
which we set appropriately for I6400 & I6500 CPUs. Further patches will
make use of these macros as appropriate.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16202/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix a regression introduced with commit fb6883e580 ("MIPS: microMIPS:
Support handling of delay slots.") and defer to `__compute_return_epc'
if the ISA bit is set in EPC with non-MIPS16, non-microMIPS hardware,
which will then arrange for a SIGBUS due to an unaligned instruction
reference. Returning EPC here is never correct as the API defines this
function's result to be either a negative error code on failure or one
of 0 and BRANCH_LIKELY_TAKEN on success.
Fixes: fb6883e580 ("MIPS: microMIPS: Support handling of delay slots.")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # 3.9+
Patchwork: https://patchwork.linux-mips.org/patch/16395/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch switches MIPS to make use of generically implemented queued
spinlocks, rather than the ticket spinlocks used previously. This allows
us to drop a whole load of inline assembly, share more generic code, and
is also a performance win.
Results from running the AIM7 short workload on a MIPS Creator Ci40 (ie.
2 core 2 thread interAptiv CPU clocked at 546MHz) with v4.12-rc4
pistachio_defconfig, with ftrace disabled due to a current bug, and both
with & without use of queued rwlocks & spinlocks:
Forks | v4.12-rc4 | +qlocks | Change
-------|-----------|----------|--------
10 | 52630.32 | 53316.31 | +1.01%
20 | 51777.80 | 52623.15 | +1.02%
30 | 51645.92 | 52517.26 | +1.02%
40 | 51634.88 | 52419.89 | +1.02%
50 | 51506.75 | 52307.81 | +1.02%
60 | 51500.74 | 52322.72 | +1.02%
70 | 51434.81 | 52288.60 | +1.02%
80 | 51423.22 | 52434.85 | +1.02%
90 | 51428.65 | 52410.10 | +1.02%
The kernels used for these tests also had my "MIPS: Hardcode cpu_has_*
where known at compile time due to ISA" patch applied, which allows the
kernel_uses_llsc checks in cmpxchg() & xchg() to be optimised away at
compile time.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16358/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch switches MIPS to make use of generically implemented queued
read/write locks, rather than the custom implementation used previously.
This allows us to drop a whole load of inline assembly, share more
generic code, and is also a performance win.
Results from running the AIM7 short workload on a MIPS Creator Ci40 (ie.
2 core 2 thread interAptiv CPU clocked at 546MHz) with v4.12-rc4
pistachio_defconfig, with ftrace disabled due to a current bug, and both
with & without use of queued rwlocks & spinlocks:
Forks | v4.12-rc4 | +qlocks | Change
-------|-----------|----------|--------
10 | 52630.32 | 53316.31 | +1.01%
20 | 51777.80 | 52623.15 | +1.02%
30 | 51645.92 | 52517.26 | +1.02%
40 | 51634.88 | 52419.89 | +1.02%
50 | 51506.75 | 52307.81 | +1.02%
60 | 51500.74 | 52322.72 | +1.02%
70 | 51434.81 | 52288.60 | +1.02%
80 | 51423.22 | 52434.85 | +1.02%
90 | 51428.65 | 52410.10 | +1.02%
The kernels used for these tests also had my "MIPS: Hardcode cpu_has_*
where known at compile time due to ISA" patch applied, which allows the
kernel_uses_llsc checks in cmpxchg() & xchg() to be optimised away at
compile time.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16357/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The __xchg() function declares its first 2 arguments in reverse order
compared to the xchg() macro, which is confusing & serves no purpose.
Reorder the arguments such that __xchg() & xchg() match.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16356/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
