MIPS: Fix comment typo

The double `it' is duplicated in the comment, remove one.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Use fallthrough for arch/mips

Convert the various /* fallthrough */ comments to the pseudo-keyword
fallthrough;

Done via script:
https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

Signed-off-by: Liangliang Huang <huangll@lemote.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Add MAC2008 Support

MAC2008 means the processor implemented IEEE754 style Fused MADD
instruction. It was introduced in Release3 but removed in Release5.

The toolchain support of MAC2008 have never landed except for Loongson
processors.

This patch aimed to disabled the MAC2008 if it's optional. For
MAC2008 only processors, we corrected math-emu behavior to align
with actual hardware behavior.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
[paulburton@kernel.org: Fixup MIPSr2-r5 check in cpu_set_fpu_2008.]
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: chenhc@lemote.com
Cc: paul.burton@mips.com
Cc: linux-kernel@vger.kernel.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 397

Based on 1 normalized pattern(s):

this program is free software you can distribute it and or modify it
under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope 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 51 franklin st fifth floor boston ma 02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 33 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081038.563233189@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove 'type' argument from access_ok() function

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

- csky still had the old "verify_area()" name as an alias.

- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)

- microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MIPS: Ensure emulated FP sets PF_USED_MATH

Emulated floating point instructions don't ensure that the PF_USED_MATH
flag is set for the task. This results in a couple of inconsistencies:

- ptrace will return the default initial state of FP registers rather
than the values actually stored in struct thread_struct, hiding
state that has been updated by emulated floating point instructions.

- If a task migrates to a CPU with an FPU after having emulated
floating point instructions then its floating point register state
will be reset to the default ~0 bit pattern, losing state from the
emulated instructions.

Fix this by calling init_fp_ctx() from fpu_emulator_cop1Handler() to
consistently initialize FP state if it was previously uninitialized,
setting the PF_USED_MATH flag in the process.

All callers of fpu_emulator_cop1Handler() either call lose_fpu(1) before
it in order to save any live FPU registers to struct thread_struct, or
in the case of do_cpu() already know that the task does not own an FPU
so lose_fpu(1) would be a no-op. Since we know that saving FP context
will be unnecessary in the case where FP context was just initialized we
move this call into fpu_emulator_cop1Handler() too, providing
consistency & avoiding needless duplication.

Calls to own_fpu(1) are common after return from
fpu_emulator_cop1Handler() too, but this would not be a no-op in the
do_cpu() case so these are left as-is. A potential future improvement
could be to have fpu_emulator_cop1Handler() restore FPU state
automatically only if it saved it, though this may not be optimal if
some callers are better off without their current calls to own_fpu(1).
One potential example of this could be mipsr2_decoder() which as-is
could end up saving & restoring FP context repeatedly & unnecessarily if
emulating multiple FP instructions.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21003/
Cc: linux-mips@linux-mips.org

MIPS: math-emu: Mark fall throughs in switch statements with a comment

Mark intentional fall throughs in switch statements with a consistent
comment.

In most of the cases, a new comment line containing text "fall through"
is inserted. In some of the cases, existing comment contained a variation
of the text "fall through" (for example, "FALL THROUGH" or "drop through").
In such cases, the existing comment is modified to contain "fall through".
Lastly, in two cases, code segments were described in comments as "fall
througs", but were in reality "breaks out" of switch statement. In such
cases, existing comments are accordingly modified.

Apart from making code easier to follow and debug, this change enables
some static code analysers to interpret newly inserted comments as their
annotations (and, therefore, not issue warnings of type "fall through in
switch statement", which is desireable, since marked fallthroughs are
intentional).

Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: Maciej W. Rozycki <macro@mips.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17588/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Avoid multiple assignment

Replace several instances of multiple assignment with individual
assignments.

Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: Maciej W. Rozycki <macro@mips.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17587/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Avoid an assignment within if statement condition

Move invocation of fpu_emu() to be out of if statement condition.

This makes code easier to follow and debug, and fixes a checkpatch
warning.

Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: Maciej W. Rozycki <macro@mips.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17586/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Use preferred flavor of unsigned integer declarations

Fix occurences of unsigned integer variable declarations that are
not preferred by standards of checkpatch scripts. This removes a
significant number of checkpatch warnings for files in math-emu
directory (several files become completely warning-free), and thus
makes easier to spot (now and in the future) other, perhaps more
significant, checkpatch errors and warnings.

Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Reviewed-by: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17582/
Signed-off-by: James Hogan <jhogan@kernel.org>

MIPS: math-emu: Fix final emulation phase for certain instructions

Fix final phase of <CLASS|MADDF|MSUBF|MAX|MIN|MAXA|MINA>.<D|S>
emulation. Provide proper generation of SIGFPE signal and updating
debugfs FP exception stats in cases of any exception flags set in
preceding phases of emulation.

CLASS.<D|S> instruction may generate "Unimplemented Operation" FP
exception. <MADDF|MSUBF>.<D|S> instructions may generate "Inexact",
"Unimplemented Operation", "Invalid Operation", "Overflow", and
"Underflow" FP exceptions. <MAX|MIN|MAXA|MINA>.<D|S> instructions
can generate "Unimplemented Operation" and "Invalid Operation" FP
exceptions.

The proper final processing of the cases when any FP exception
flag is set is achieved by replacing "break" statement with "goto
copcsr" statement. With such solution, this patch brings the final
phase of emulation of the above instructions consistent with the
one corresponding to the previously implemented emulation of other
related FPU instructions (ADD, SUB, etc.).

Fixes: 38db37ba069f ("MIPS: math-emu: Add support for the MIPS R6 CLASS FPU instruction")
Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction")
Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction")
Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction")
Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction")
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.3+
Patchwork: https://patchwork.linux-mips.org/patch/17581/
Signed-off-by: James Hogan <jhogan@kernel.org>

MIPS: math-emu: Remove pr_err() calls from fpu_emu()

The FPU emulator includes 2 calls to pr_err() which are triggered by
invalid instruction encodings for MIPSr6 cmp.cond.fmt instructions.
These cases are not kernel errors, merely invalid instructions which are
already handled by delivering a SIGILL which will provide notification
that something failed in cases where that makes sense.

In cases where that SIGILL is somewhat expected & being handled, for
example when crashme happens to generate one of the affected bad
encodings, the message is printed with no useful context about what
triggered it & spams the kernel log for no good reason.

Remove the pr_err() calls to make crashme run silently & treat the bad
encodings the same way we do others, with a SIGILL & no further kernel
log output.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: f8c3c6717a71 ("MIPS: math-emu: Add support for the CMP.condn.fmt R6 instruction")
Cc: linux-mips@linux-mips.org
Cc: stable <stable@vger.kernel.org> # v4.3+
Patchwork: https://patchwork.linux-mips.org/patch/17253/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add FP emu debugfs stats for individual instructions

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>

MIPS: math-emu: Add FP emu debugfs statistics for branches

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>

MIPS: math-emu: CLASS.D: Zero bits 32-63 of the result

Fix content of CLASS.D output bits 32-63 to match hardware behavior.

Prior to this patch, bits 32-63 of CLASS.D output were not
initialized, causing different 32-63 bits content of CLASS.D, based on
circumstances. However, the hardware consistently returns all these
bits zeroed. The documentation is not clear whether these bits should
be zero or unpredictable. Since technically "all zero" case still can
be viewed as belonging to "unpredictable" class of results, it is
better to zero bits 32-63.

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/17142/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: RINT.<D|S>: Fix several problems by reimplementation

Reimplement RINT.<D|S> kernel emulation so that all RINT.<D|S>
specifications are met.

For the sake of simplicity, let's analyze RINT.S only. Prior to
this patch, RINT.S emulation was essentially implemented as (in
pseudocode) <output> = ieee754sp_flong(ieee754sp_tlong(<input>)),
where ieee754sp_tlong() and ieee754sp_flong() are functions
providing conversion from double to integer, and from integer
to double, respectively. On surface, this implementation looks
correct, but actually fails in many cases. Following problems
were detected:

1. NaN and infinity cases will not be handled properly. The
function ieee754sp_flong() never returns NaN nor infinity.
2. For RINT.S, for all inputs larger than LONG_MAX, and smaller
than FLT_MAX, the result will be wrong, and the overflow
exception will be erroneously set. A similar problem for
negative inputs exists as well.
3. For some rounding modes, for some negative inputs close to zero,
the return value will be zero, and should be -zero. This is
because ieee754sp_flong() never returns -zero.

This patch removes the problems above by implementing dedicated
functions for RINT.<D|S> emulation.

The core of the new function functionality is adapted version of
the core of the function ieee754sp_tlong(). However, there are many
details that are implemented to match RINT.<D|S> specification. It
should be said that the functionality of ieee754sp_tlong() actually
closely corresponds to CVT.L.S instruction, and it is used while
emulating CVT.L.S. However, RINT.S and CVT.L.S instructions differ
in many aspects. This patch fulfills missing support for RINT.<D|S>.

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: David S. Miller <davem@davemloft.net>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17141/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: CMP.Sxxx.<D|S>: Prevent occurrences of SIGILL crashes

Fix CMP.Sxxx.<D|S> SIGILL crashes by fixing main switch/case statement
in fpu_emul() function so that inadvertent fall-troughs are prevented.

Consider, let's say, CMP.SAF.S instruction when one of inputs is zero
and another input is a signaling NaN. The desired output is zero, and
the exception flag "invalid operation" set. For such case, the main
portion of the implementation is within "d_fmt" case of the main
"switch/case" statement in fpu_emul() function. The execution will
follow one of "if-else" branches that doesn't contain "goto cop1scr;"
statement, and will therefore reach the end of "d_fmt" case. It will
subsequently fall through to the next case, "l_fmt". After following
similar pattern, the execution will fall through to the succeeding
case, which is "default". The "default" case contains "return SIGILL;"
statement only. This means that the caller application will crash
with "illegal instruction" message.

It is obvious that above described fall-throughs are unnecessary and
harmful. This patch rectifies that behavior by providing "break;"
statements at the end of cases "d_fmt" and "l_fmt".

There are 22 instructions affected by this problem:

CMP.<SAF|SEQ|SLE|SLT|SNE|SOR|SUEQ|SULE|SULT|SUN|SUNE>.<D|S>.

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/17140/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Correct user fault_addr type

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>

MIPS: math-emu: do not use bools for arithmetic

GCC-7 complains about a boolean value being used with an arithmetic
AND:

arch/mips/math-emu/cp1emu.c: In function 'cop1Emulate':
arch/mips/math-emu/cp1emu.c:838:14: warning: '~' on a boolean expression [-Wbool-operation]
fpr = (x) & ~(cop1_64bit(xcp) == 0); \
^
arch/mips/math-emu/cp1emu.c:1068:3: note: in expansion of macro 'DITOREG'
DITOREG(dval, MIPSInst_RT(ir));
^~~~~~~
arch/mips/math-emu/cp1emu.c:838:14: note: did you mean to use logical not?
fpr = (x) & ~(cop1_64bit(xcp) == 0); \

Since cop1_64bit() returns and int, just flip the LSB.

Suggested-by: Maciej W. Rozycki <macro@imgtec.com>
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Reviewed-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17058/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: For MFHC1/MTHC1 also return SIGILL right away

Update commit 1ac944007bed ("MIPS: math-emu: Add mfhc1 & mthc1
support.") and like done throughout `cop1Emulate' for other cases also
for the MFHC1 and MTHC1 instructions return SIGILL right away rather
than jumping to a single `return' statement.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16401/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Prevent wrong ISA mode instruction emulation

Terminate FPU emulation immediately whenever an ISA mode switch has been
observed. This is so that we do not interpret machine code in the wrong
mode, for example when a regular MIPS FPU instruction has been placed in
a delay slot of a jump that switches into the MIPS16 mode, as with the
following code (taken from a GCC test suite case):

00400650 <set_fast_math>:
400650: 3c020100 lui v0,0x100
400654: 03e00008 jr ra
400658: 44c2f800 ctc1 v0,c1_fcsr
40065c: 00000000 nop

[...]

004012d0 <__libc_csu_init>:
4012d0: f000 6a02 li v0,2
4012d4: f150 0b1c la v1,3f9430 <_DYNAMIC-0x6df0>
4012d8: f400 3240 sll v0,16
4012dc: e269 addu v0,v1
4012de: 659a move gp,v0
4012e0: f00c 64f6 save a0-a2,48,ra,s0-s1
4012e4: 673c move s1,gp
4012e6: f010 9978 lw v1,-32744(s1)
4012ea: d204 sw v0,16(sp)
4012ec: eb40 jalr v1
4012ee: 653b move t9,v1
4012f0: f010 997c lw v1,-32740(s1)
4012f4: f030 9920 lw s1,-32736(s1)
4012f8: e32f subu v1,s1
4012fa: 326b sra v0,v1,2
4012fc: d206 sw v0,24(sp)
4012fe: 220c beqz v0,401318 <__libc_csu_init+0x48>
401300: 6800 li s0,0
401302: 99e0 lw a3,0(s1)
401304: 4801 addiu s0,1
401306: 960e lw a2,56(sp)
401308: 4904 addiu s1,4
40130a: 950d lw a1,52(sp)
40130c: 940c lw a0,48(sp)
40130e: ef40 jalr a3
401310: 653f move t9,a3
401312: 9206 lw v0,24(sp)
401314: ea0a cmp v0,s0
401316: 61f5 btnez 401302 <__libc_csu_init+0x32>
401318: 6476 restore 48,ra,s0-s1
40131a: e8a0 jrc ra

Here `set_fast_math' is called from `40130e' (`40130f' with the ISA bit)
and emulation triggers for the CTC1 instruction. As it is in a jump
delay slot emulation continues from `401312' (`401313' with the ISA
bit). However we have no path to handle MIPS16 FPU code emulation,
because there are no MIPS16 FPU instructions. So the default emulation
path is taken, interpreting a 32-bit word fetched by `get_user' from
`401313' as a regular MIPS instruction, which is:

401313: f5ea0a92 sdc1 $f10,2706(t7)

This makes the FPU emulator proceed with the supposed SDC1 instruction
and consequently makes the program considered here terminate with
SIGSEGV.

A similar although less severe issue exists with pure-microMIPS
processors in the case where similarly an FPU instruction is emulated in
a delay slot of a register jump that (incorrectly) switches into the
regular MIPS mode. A subsequent instruction fetch from the jump's
target is supposed to cause an Address Error exception, however instead
we proceed with regular MIPS FPU emulation.

For simplicity then, always terminate the emulation loop whenever a mode
change is detected, denoted by an ISA mode bit flip. As from commit
377cb1b6c16a ("MIPS: Disable MIPS16/microMIPS crap for platforms not
supporting these ASEs.") the result of `get_isa16_mode' can be hardcoded
to 0, so we need to examine the ISA mode bit by hand.

This complements commit 102cedc32a6e ("MIPS: microMIPS: Floating point
support.") which added JALX decoding to FPU emulation.

Fixes: 102cedc32a6e ("MIPS: microMIPS: Floating point support.")
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/16393/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Fix BC1EQZ and BC1NEZ condition handling

Correct the treatment of branching conditions for BC1EQZ and BC1NEZ
instructions in function isBranchInstr().

Previously, corresponding conditions were swapped, which in turn meant
that, for these two instructions, function isBranchInstr() returned
wrong value in its output parameter contpc.

This change is actually an extension of the fix done by the commit
93583e178ebf ("MIPS: math-emu: Fix BC1{EQ,NE}Z emulation"). That commit
dealt with a similar problem in function cop1Emulate(), while this
commit deals with condition handling in function isBranchInstr().
The code styles of changes in these two commits are kept as
consistent as possible.

Signed-off-by: Douglas Leung <douglas.leung@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: james.hogan@imgtec.com
Cc: leonid.yegoshin@imgtec.com
Cc: petar.jovanovic@imgtec.com
Cc: goran.ferenc@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15489/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: remove redundant #include <linux/kconfig.h>

Kernel source files need not include <linux/kconfig.h> explicitly
because the top Makefile forces to include it with:

-include $(srctree)/include/linux/kconfig.h

This commit removes explicit includes except the following:

* arch/s390/include/asm/facilities_src.h
* tools/testing/radix-tree/linux/kernel.h

These two are used for host programs.

Link: http://lkml.kernel.org/r/1473656164-11929-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tree-wide: replace config_enabled() with IS_ENABLED()

The use of config_enabled() against config options is ambiguous. In
practical terms, config_enabled() is equivalent to IS_BUILTIN(), but the
author might have used it for the meaning of IS_ENABLED(). Using
IS_ENABLED(), IS_BUILTIN(), IS_MODULE() etc. makes the intention
clearer.

This commit replaces config_enabled() with IS_ENABLED() where possible.
This commit is only touching bool config options.

I noticed two cases where config_enabled() is used against a tristate
option:

- config_enabled(CONFIG_HWMON)
[ drivers/net/wireless/ath/ath10k/thermal.c ]

- config_enabled(CONFIG_BACKLIGHT_CLASS_DEVICE)
[ drivers/gpu/drm/gma500/opregion.c ]

I did not touch them because they should be converted to IS_BUILTIN()
in order to keep the logic, but I was not sure it was the authors'
intention.

Link: http://lkml.kernel.org/r/1465215656-20569-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: yu-cheng yu <yu-cheng.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Will Drewry <wad@chromium.org>
Cc: Nikolay Martynov <mar.kolya@gmail.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Rafal Milecki <zajec5@gmail.com>
Cc: James Cowgill <James.Cowgill@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Mikko Rapeli <mikko.rapeli@iki.fi>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Tony Wu <tung7970@gmail.com>
Cc: Huaitong Han <huaitong.han@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Gelmini <andrea.gelmini@gelma.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Rabin Vincent <rabin@rab.in>
Cc: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: David Daney <david.daney@cavium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MIPS: Use per-mm page to execute branch delay slot instructions

In some cases the kernel needs to execute an instruction from the delay
slot of an emulated branch instruction. These cases include:

- Emulated floating point branch instructions (bc1[ft]l?) for systems
which don't include an FPU, or upon which the kernel is run with the
"nofpu" parameter.

- MIPSr6 systems running binaries targeting older revisions of the
architecture, which may include branch instructions whose encodings
are no longer valid in MIPSr6.

Executing instructions from such delay slots is done by writing the
instruction to memory followed by a trap, as part of an "emuframe", and
executing it. This avoids the requirement of an emulator for the entire
MIPS instruction set. Prior to this patch such emuframes are written to
the user stack and executed from there.

This patch moves FP branch delay emuframes off of the user stack and
into a per-mm page. Allocating a page per-mm leaves userland with access
to only what it had access to previously, and compared to other
solutions is relatively simple.

When a thread requires a delay slot emulation, it is allocated a frame.
A thread may only have one frame allocated at any one time, since it may
only ever be executing one instruction at any one time. In order to
ensure that we can free up allocated frame later, its index is recorded
in struct thread_struct. In the typical case, after executing the delay
slot instruction we'll execute a break instruction with the BRK_MEMU
code. This traps back to the kernel & leads to a call to do_dsemulret
which frees the allocated frame & moves the user PC back to the
instruction that would have executed following the emulated branch.
In some cases the delay slot instruction may be invalid, such as a
branch, or may trigger an exception. In these cases the BRK_MEMU break
instruction will not be hit. In order to ensure that frames are freed
this patch introduces dsemul_thread_cleanup() and calls it to free any
allocated frame upon thread exit. If the instruction generated an
exception & leads to a signal being delivered to the thread, or indeed
if a signal simply happens to be delivered to the thread whilst it is
executing from the struct emuframe, then we need to take care to exit
the frame appropriately. This is done by either rolling back the user PC
to the branch or advancing it to the continuation PC prior to signal
delivery, using dsemul_thread_rollback(). If this were not done then a
sigreturn would return to the struct emuframe, and if that frame had
meanwhile been used in response to an emulated branch instruction within
the signal handler then we would execute the wrong user code.

Whilst a user could theoretically place something like a compact branch
to self in a delay slot and cause their thread to become stuck in an
infinite loop with the frame never being deallocated, this would:

- Only affect the users single process.

- Be architecturally invalid since there would be a branch in the
delay slot, which is forbidden.

- Be extremely unlikely to happen by mistake, and provide a program
with no more ability to harm the system than a simple infinite loop
would.

If a thread requires a delay slot emulation & no frame is available to
it (ie. the process has enough other threads that all frames are
currently in use) then the thread joins a waitqueue. It will sleep until
a frame is freed by another thread in the process.

Since we now know whether a thread has an allocated frame due to our
tracking of its index, the cookie field of struct emuframe is removed as
we can be more certain whether we have a valid frame. Since a thread may
only ever have a single frame at any given time, the epc field of struct
emuframe is also removed & the PC to continue from is instead stored in
struct thread_struct. Together these changes simplify & shrink struct
emuframe somewhat, allowing twice as many frames to fit into the page
allocated for them.

The primary benefit of this patch is that we are now free to mark the
user stack non-executable where that is possible.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: Maciej Rozycki <maciej.rozycki@imgtec.com>
Cc: Faraz Shahbazker <faraz.shahbazker@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13764/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: inst.h: Rename cbcond{0,1}_op to pop{1,3}0_op

The opcodes currently defined in inst.h as cbcond0_op & cbcond1_op are
actually defined in the MIPS base instruction set manuals as pop10 &
pop30 respectively. Rename them as such, for consistency with the
documentation.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: inst.h: Rename b{eq,ne}zcji[al]c_op to pop{6,7}6_op

The opcodes currently defined in inst.h as beqzcjic_op & bnezcjialc_op
are actually defined in the MIPS base instruction set manuals as pop66 &
pop76 respectively. Rename them as such, for consistency with the
documentation.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MIPS: math-emu: Fix jalr emulation when rd == $0

When emulating a jalr instruction with rd == $0, the code in
isBranchInstr was incorrectly writing to GPR $0 which should actually
always remain zeroed. This would lead to any further instructions
emulated which use $0 operating on a bogus value until the task is next
context switched, at which point the value of $0 in the task context
would be restored to the correct zero by a store in SAVE_SOME. Fix this
by not writing to rd if it is $0.

Fixes: 102cedc32a6e ("MIPS: microMIPS: Floating point support.")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable <stable@vger.kernel.org> # v3.10
Patchwork: https://patchwork.linux-mips.org/patch/13160/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Emulate MIPSr6 sel.fmt instruction

Add support for emulating the MIPSr6 sel.fmt instruction, which was
previously missing from the FPU emulation code. This instruction selects
its result from 2 possible source registers, based upon bit 0 of the
destination register, and is valid only for S (single) & D (double) data
types.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.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/13153/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Fix BC1{EQ,NE}Z emulation

The conditions for branching when emulating the BC1EQZ & BC1NEZ
instructions were backwards, leading to each of those instructions being
treated as the other. Fix this by reversing the conditions, and clear up
the code a little for readability & checkpatch.

Fixes: c909ca718e8f ("MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13150/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Correctly handle NOP emulation

Fix an issue introduced with commit 9ab4471c9f1b ("MIPS: math-emu:
Correct delay-slot exception propagation") where the emulation of a NOP
instruction signals the need to terminate the emulation loop. This in
turn, if the PC has not changed from the entry to the loop, will cause
the kernel to terminate the program with SIGILL.

Consider this program:

static double div(double d)
{
do
d /= 2.0;
while (d > .5);
return d;
}

int main(int argc, char **argv)
{
return div(argc);
}

which gets compiled to the following binary code:

00400490 <main>:
400490: 44840000 mtc1 a0,$f0
400494: 3c020040 lui v0,0x40
400498: d44207f8 ldc1 $f2,2040(v0)
40049c: 46800021 cvt.d.w $f0,$f0
4004a0: 46220002 mul.d $f0,$f0,$f2
4004a4: 4620103c c.lt.d $f2,$f0
4004a8: 4501fffd bc1t 4004a0 <main+0x10>
4004ac: 00000000 nop
4004b0: 4620000d trunc.w.d $f0,$f0
4004b4: 03e00008 jr ra
4004b8: 44020000 mfc1 v0,$f0
4004bc: 00000000 nop

Where the FPU emulator is used, depending on the number of command-line
arguments this code will either run to completion or terminate with
SIGILL.

If no arguments are specified, then BC1T will not be taken, NOP will not
be emulated and code will complete successfully.

If one argument is specified, then BC1T will be taken once and NOP will
be emulated. At this point the entry PC value will be 0x400498 and the
new PC value, set by `mips_dsemul' will be 0x4004a0, the target of BC1T.
The emulation loop will terminate, but SIGILL will not be issued,
because the PC has changed. The FPU emulator will be entered again and
on the second execution BC1T will not be taken, NOP will not be emulated
and code will complete successfully.

If two or more arguments are specified, then the first execution of BC1T
will proceed as above. Upon reentering the FPU emulator the emulation
loop will continue to BC1T, at which point the branch will be taken and
NOP emulated again. At this point however the entry PC value will be
0x4004a0, the same as the target of BC1T. This will make the emulator
conclude that execution has not advanced and therefore an unsupported
FPU instruction has been encountered, and SIGILL will be sent to the
process.

Fix the problem by extending the internal API of `mips_dsemul', making
it return -1 if no delay slot emulation frame has been made, the
instruction has been handled and execution of the emulation loop needs
to continue as if nothing happened. Remove code from `mips_dsemul' to
reproduce steps made by the emulation loop at the conclusion of each
iteration, as those will be reached normally now. Adjust call sites
accordingly. Document the API.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12172/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction

MIPS R6 introduced the following instruction:
Scalar Floating-Point Maximum and
Scalar Floating-Point argument with Maximum Absolute Value
MAX.fmt writes the maximum value of the inputs fs and ft to the
destination fd.
MAXA.fmt takes input arguments fs and ft and writes the argument with
the maximum absolute value to the destination fd.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10961/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction

MIPS R6 introduced the following instruction:
Scalar Floating-Point Minimum and
Scalar Floating-Point argument with Minimum Absolute Value

MIN.fmt writes the minimum value of the inputs fs and ft to the
destination fd.
MINA.fmt takes input arguments fs and ft and writes the argument with
the minimum absolute value to the destination fd.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10960/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 CLASS FPU instruction

MIPS R6 introduced the following instruction:
Stores in fd a bit mask reflecting the floating-point class of the
floating point scalar value fs.

CLASS.fmt: FPR[fd] = class(FPR[fs])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10959/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 RINT FPU instruction

MIPS R6 introduced the following instruction:
Floating-Point Round to Integral
Scalar floating-point round to integral floating point value.

RINT.fmt: FPR[fd] = round_int(FPR[fs])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10958/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction

MIPS R6 introduced the following instruction:
Floating Point Fused Multiply Subtract:
MSUBF.fmt To perform a fused multiply-subtract of FP values.

MSUBF.fmt: FPR[fd] = FPR[fd] - (FPR[fs] x FPR[ft])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10957/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction

MIPS R6 introduced the following instruction:
Floating Point Fused Multiply Add:
MADDF.fmt To perform a fused multiply-add of FP values.

MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft])

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10956/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 SELNEZ FPU instruction

MIPS R6 introduced the following instruction:
SELNEZ.fmt: FPR[fd]  FPR[ft].bit0 ? FPR[fs] : 0

Add support for emulating the single and double precision
formats of the said instruction.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10955/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the MIPS R6 SELEQZ FPU instruction

MIPS R6 introduced the following instruction:
SELEQZ.fmt: FPR[fd]  FPR[ft].bit0 ? 0 : FPR[fs]

Add support for emulating the single and double precision formats
of the said instruction.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10954/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add support for the CMP.condn.fmt R6 instruction

Add support for emulating the new CMP.condn.fmt R6 instructions and
return SIGILL for the old C.cond.fmt if R2 emulation is not enabled
since it's not supported by R6.

The functionality of the new CMP.condn.fmt is the following one:

If the comparison specified by the condn field of the instruction
is true for the operand values, the result is true; otherwise, the
result is false. If no exception is taken, the result is written into
FPR fd; true is all 1s and false is all 0s repeated the operand width
of fmt. All other bits beyond the operand width fmt are UNPREDICTABLE.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10953/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions

Commit c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
added support for emulating the new R6 BC1{EQ,NE}Z branches but it missed
the case where the instruction that caused the exception was not on a DS.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10738/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Allow m{f,t}hc emulation on MIPS R6

The mfhc/mthc instructions are supported on MIPS R6 so emulate
them if needed.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10737/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cp1emu: Fix closing bracket for the d_fmt case

The double format (d_fmt) case uses an opening bracket which then
closes at the end of the word format (w_fmt). This can be rather confusing
so add the closing bracket at the end of the d_fmt case and use another one
for the w_fmt one.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10733/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix erroneous JR emulation for MIPS R6

Commit 5f9f41c474befb4ebbc40b27f65bb7d649241581 ("MIPS: kernel: Prepare
the JR instruction for emulation on MIPS R6") added support for
emulating the JR instruction on MIPS R6 cores but that introduced a bug
which could be triggered when hitting a JALR opcode because the code used
the wrong field in the 'r_format' struct to determine the instruction
opcode. This lead to crashes because an emulated JALR instruction was
treated as a JR one when the R6 emulator was turned off.

Fixes: 5f9f41c474be ("MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6")
Cc: <stable@vger.kernel.org> # 4.0+
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10583/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix branch emulation for BLTC and BGEC instructions

Commits f1b44067c19258b7614e3cd09dfe8d8e12ff5895 ("MIPS: Emulate the
new MIPS R6 B{L,G}T{Z,}{AL,}C instructions") and commit
a8ff66f52d3f17b5ae793955270675c197f73d6c ("MIPS: Emulate the new MIPS
R6 B{L,G}E{Z,}{AL,}C instructions") added support for emulating various
branch compact instructions. However, it missed the case for those which
use the old BLEZL and BGTZL opcodes leading to random crashes when the R6
emulator is disabled. We fix this by ensuring that the 'rt' field is not
zero which is always true for these branch compact instructions.

Fixes: f1b44067c192 ("MIPS: Emulate the new MIPS R6 B{L,G}T{Z,}{AL,}C instructions")
Fixes: a8ff66f52d3f ("MIPS: Emulate the new MIPS R6 B{L,G}E{Z,}{AL,}C instructions")
Cc: <stable@vger.kernel.org> # 4.0+
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10582/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix a preemption issue with thread's FPU defaults

Fix "BUG: using smp_processor_id() in preemptible" reported in accesses
to thread's FPU defaults: the value to initialise FSCR to at program
startup, the FCSR r/w mask and the contents of FIR in full FPU
emulation, removing a regression introduced with 9b26616c [MIPS: Respect
the ISA level in FCSR handling] and f6843626 [MIPS: math-emu: Set FIR
feature flags for full emulation].

Use `boot_cpu_data' to obtain the data from, following the approach that
`cpu_has_*' macros take and avoiding the call to `smp_processor_id' made
in the reference to `current_cpu_data'. The contents of FSCR have to be
consistent across processors in an SMP system, the settings there must
not change as a thread is migrated across processors. And the contents
of FIR are guaranteed to be consistent in FPU emulation, by definition.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Tested-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Tested-by: Paul Martin <paul.martin@codethink.co.uk>
Cc: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10030/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Respect the ISA level in FCSR handling

Define the central place the default FCSR value is set from, initialised
in `cpu_probe'. Determine the FCSR mask applied to values written to
the register with CTC1 in the full emulation mode and via ptrace(2),
according to the ISA level of processor hardware or the writability of
bits 31:18 if actual FPU hardware is used.

Software may rely on FCSR bits whose functions our emulator does not
implement, so it should not allow them to be set or software may get
confused. For ptrace(2) it's just sanity.

[ralf@linux-mips.org: Fixed double inclusion of <asm/current.h>.]

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9711/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Define IEEE 754-2008 feature control bits

Define IEEE 754-2008 feature control bits: FIR.HAS2008, FCSR.ABS2008 and
FCSR.NAN2008, and update the `_ieee754_csr' structure accordingly.

For completeness define FIR.UFRP too.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9709/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Implement the FCCR, FEXR and FENR registers

Implement the FCCR, FEXR and FENR "shadow" FPU registers for the
architecture levels that include them, for the CFC1 and CTC1
instructions in the full emulation mode.

For completeness add macros for the CP1 UFR and UNFR registers too, no
actual implementation though.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9708/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Set FIR feature flags for full emulation

Implement FIR feature flags in the FPU emulator according to features
supported and architecture level requirements. The W, L and F64 bits
have only been added at level #2 even though the features they refer to
were also included with the MIPS64r1 ISA and the W fixed-point format
also with the MIPS32r1 ISA.

This is only relevant for the full emulation mode and the emulated CFC1
instruction as well as ptrace(2) accesses.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9707/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Correct delay-slot exception propagation

Restore EPC at the branch whose delay slot is emulated if the delay-slot
instruction signals. This is so that code in `fpu_emulator_cop1Handler'
does not see EPC having advanced and mistakenly successfully resume
userland execution from the location at the branch target in that case.
Restoring EPC guarantees an immediate exit from the emulation loop and
if EPC hasn't advanced at all since entering the loop, also issuing the
signal reported by the delay-slot instruction.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9701/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Correct FP ISA requirements

Correct ISA requirements for floating-point instructions:

* the CU3 exception signifies a real COP3 instruction in MIPS I & II,

* the BC1FL and BC1TL instructions are not supported in MIPS I,

* the SQRT.fmt instructions are indeed supported in MIPS II,

* the LDC1 and SDC1 instructions are indeed supported in MIPS32r1,

* the CEIL.W.fmt, FLOOR.W.fmt, ROUND.W.fmt and TRUNC.W.fmt instructions
are indeed supported in MIPS32,

* the CVT.L.fmt and CVT.fmt.L instructions are indeed supported in
MIPS32r2 and MIPS32r6,

* the CEIL.L.fmt, FLOOR.L.fmt, ROUND.L.fmt and TRUNC.L.fmt instructions
are indeed supported in MIPS32r2 and MIPS32r6,

* the RSQRT.fmt and RECIP.fmt instructions are indeed supported in
MIPS64r1,

Also simplify conditionals for MIPS III and MIPS IV FPU instructions and
the handling of the MOVCI minor opcode.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9700/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Factor out CFC1/CTC1 emulation

Move CFC1/CTC1 emulation code to separate functions to avoid excessive
indentation in forthcoming changes. Adjust formatting in a minor way
and remove extraneous round brackets.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9682/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Remove `modeindex' macro

Commit 56a64733 [MIPS: math-emu: Switch to using the MIPS rounding
modes.] removed the distinction between hardware and emulator rounding
mode encodings, the hardware encoding is now used in emulation as well.
Complement the change and remove the `modeindex' macro previously used
for indexing into encoding translation tables, it now does nothing and
only obfuscates code by reinserting the value extracted from FCSR.
Adjust comments accordingly.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9680/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Reindent `bc_op' emulation

Correct the double-tab indentation of the branch-likely not-taken case.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9674/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Handle MIPS IV, V and R2 FPU instructions on MIPS R6 as well

MIPS R2 FPU instructions are also present in MIPS R6 so amend the
preprocessor definitions to take MIPS R6 into consideration.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6

MIPS R6 removed quite a few R2 instructions. However, there
is plenty of <R6 userland code so we add an in-kernel emulator
so we can still be able to execute all R2 userland out there.

The emulator comes with a handy debugfs under /mips/ directory
(r2-emul-stats) to provide some basic statistics of the
instructions that are being emulated.

Below are some statistics from booting a minimal buildroot image:

Instruction Total BDslot
------------------------------
movs 236969 0
hilo 56686 0
muls 55279 0
divs 10941 0
dsps 0 0
bops 1 0
traps 0 0
fpus 0 0
loads 214981 17
stores 103364 0
llsc 56898 0
dsemul 150418 0
jr 370158
bltzl 43
bgezl 1594
bltzll 0
bgezll 0
bltzal 39
bgezal 39
beql 14503
bnel 138741
blezl 0
bgtzl 3988

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions

MIPS R6 uses the <R6 sdc2 opcode for the new BNEZC and JIALC instructions

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 BEQZC and JIC instructions

MIPS R6 uses the <R6 ldc2 opcode for the new BEQZC and JIC instructions

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 BALC instruction

MIPS R6 uses the <R6 swc2 opcode for the new BALC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 BNVC, BNEC and BNEZLAC instructions

MIPS R6 uses the <R6 DADDI opcode for the new BNVC, BNEC and
BNEZLAC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions

MIPS R6 uses the <R6 ADDI opcode for the new BOVC, BEQC and
BEQZALC instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 branch compact (BC) instruction

MIPS R6 uses the <R6 LWC2 opcode for the new BC instruction.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 B{L,G}T{Z,}{AL,}C instructions

MIPS R6 added the following four instructions which share the
BGTZ and BGTZL opcode:

BLTZALC: Compact branch-and-link if GPR rt is < to zero
BGTZALC: Compact branch-and-link if GPR rt is > to zero
BLTZL : Compact branch if GPR rt is < to zero
BGTZL : Compact branch if GPR rt is > to zero
BLTC : Compact branch if GPR rs is less than GPR rt
BLTUC : Similar to BLTC but unsigned

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the new MIPS R6 B{L,G}Ε{Z,}{AL,}C instructions

MIPS R6 added the following four instructions which share the
BLEZ and BLEZL opcodes:

BLEZALC: Compact branch-and-link if GPR rt is <= to zero
BGEZALC: Compact branch-and-link if GPR rt is >= to zero
BLEZC : Compact branch if GPR rt is <= to zero
BGEZC : Compact branch if GPR rt is >= to zero
BGEC : Compact branch if GPR rs is less than or equal to GPR rt
BGEUC : Similar to BGEC but unsigned.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Emulate the BC1{EQ,NE}Z FPU instructions

MIPS R6 introduced the following two branch instructions for COP1:

BC1EQZ: Branch if Cop1 (FPR) Register Bit 0 is Equal to Zero
BC1NEZ: Branch if Cop1 (FPR) Register Bit 0 is Not Equal to Zero

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: kernel: branch: Do not emulate the branch likelies on MIPS R6

MIPS R6 removed the BLTZL, BGEZL, BLTZAL, BGEZAL, BEQL, BNEL, BLEZL,
BGTZL branch likely instructions so we must not try to emulate them on
MIPS R6 if the R2-to-R6 emulator is not present.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6

The MIPS R6 JR instruction is an alias to the JALR one, so it may
need emulation for non-R6 userlands.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: Support for hybrid FPRs

Hybrid FPRs is a scheme where scalar FP registers are 64b wide, but
accesses to odd indexed single registers use bits 63:32 of the
preceeding even indexed 64b register. In this mode all FP code
except that built for the plain FP64 ABI can execute correctly. Most
notably a combination of FP64A & FP32 code can execute correctly,
allowing for existing FP32 binaries to be linked with new FP64A binaries
that can make use of 64 bit FP & MSA.

Hybrid FPRs are implemented by setting both the FR & FRE bits, trapping
& emulating single precision FP instructions (via Reserved Instruction
exceptions) whilst allowing others to execute natively. It therefore has
a penalty in terms of execution speed, and should only be used when no
fully native mode can be. As more binaries are recompiled to use either
the FPXX or FP64(A) ABIs, the need for hybrid FPRs should diminish.
However in the short to mid term it allows for a gradual transition
towards that world, rather than a complete ABI break which is not
feasible for some users & not desirable for many.

A task will be executed using the hybrid FPR scheme when its
TIF_HYBRID_FPREGS flag is set & TIF_32BIT_FPREGS is clear. A further
patch will set the flags as necessary, this patch simply adds the
infrastructure necessary for the hybrid FPR mode to work.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7683/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix build with binutils 2.24.51+

Starting with version 2.24.51.20140728 MIPS binutils complain loudly
about mixing soft-float and hard-float object files, leading to this
build failure since GCC is invoked with "-msoft-float" on MIPS:

{standard input}: Warning: .gnu_attribute 4,3 requires `softfloat'
LD arch/mips/alchemy/common/built-in.o
mipsel-softfloat-linux-gnu-ld: Warning: arch/mips/alchemy/common/built-in.o
uses -msoft-float (set by arch/mips/alchemy/common/prom.o),
arch/mips/alchemy/common/sleeper.o uses -mhard-float

To fix this, we detect if GAS is new enough to support "-msoft-float" command
option, and if it does, we can let GCC pass it to GAS; but then we also need
to sprinkle the files which make use of floating point registers with the
necessary ".set hardfloat" directives.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/8355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: cp1emu: Fix ISA restrictions for cop1x_op instructions

Commit 08a07904e1828 ("MIPS: math-emu: Remove most ifdefery") removed
the #ifdef ISA conditions and switched to runtime detection. However,
according to the instruction set manual, the cop1x_op instructions are
available in >=MIPS32r2 as well. This fixes a problem on MIPS32r2
with the ntpd package which failed to execute with a SIGILL exit code due
to the fact that a madd.d instruction was not being emulated.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: 08a07904e1828 ("MIPS: math-emu: Remove most ifdefery")
Cc: <stable@vger.kernel.org> # v3.16+
Cc: linux-mips@linux-mips.org
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/8173/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix MFC1 & MFHC1 emulation for 64-bit MIPS systems

Commit bbd426f542cb "MIPS: Simplify FP context access" modified the
SIFROMREG & SIFROMHREG macros such that they return unsigned rather
than signed 32b integers. I had believed that to be fine, but
inadvertently missed the MFC1 & MFHC1 cases which write to a struct
pt_regs regs element. On MIPS32 this is fine, but on 64 bit those
saved regs' fields are 64 bit wide. Using unsigned values caused the
32 bit value from the FP register to be zero rather than sign extended
as the architecture specifies, causing incorrect emulation of the
MFC1 & MFHc1 instructions. Fix by reintroducing the casts to signed
integers, and therefore the sign extension.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: stable@vger.kernel.org # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7848/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Fix instruction decoding.

Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: OCTEON: Enable use of FPU

Some versions of the assembler will not assemble CFC1 for OCTEON, so
override the ISA for these.

Add r4k_fpu.o to handle low level FPU initialization.

Modify octeon_switch.S to save the FPU registers. And include
r4k_switch.S to pick up more FPU support.

Get rid of "#define cpu_has_fpu 0"

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7006/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add IEEE754 exception statistics to debugfs

Sometimes it's useful to let the user, while doing performance research,
know what in the IEEE754 exceptions has caused many times of FP emulation
when running a specific application. This patch adds 5 more files to
/sys/kernel/debug/mips/fpuemustats/, whose filenames begin with "ieee754".
These stats are in addition to the existing cp1ops, cp1xops, errors, loads
and stores, which may not be useful in understanding the reasons of ieee754
exceptions.

[ralf@linux-mips.org: Fixed reject due to other changes to the kernel
FP assist software.]

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Steven.Hill@imgtec.com
Cc: james.hogan@imgtec.com
Patchwork: http://patchwork.linux-mips.org/patch/7044/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Reduce microMIPS bloat.

Move microMIPS32_to_MIPS32() to a separate file which only gets built
for mipsMIPS configurations; for other configurations the optimizer
eleminates calls to microMIPS32_to_MIPS32().

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Switch to using the MIPS rounding modes.

Previously math-emu was using the IEEE-754 constants internally. These
were differing by having the constants for rounding to +/- infinity
switched, so a conversion was necessary. This would be entirely
avoidable if the MIPS constants were used throughout, so get rid of
the bloat.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Sort out mm_isBranchInstr.

mm_isBranchInstr() did reside in the math emu code even though it logically
is separate and also is used outside the math emu code. In addition GCC 4.9.0
leaves the following unnnecessarily bloated function body for a non-microMIPS
configuration:

<mm_isBranchInstr>:
105c: afa50004 sw a1,4(sp)
1060: afa60008 sw a2,8(sp)
1064: afa7000c sw a3,12(sp)
1068: 03e00008 jr ra
106c: 00001021 move v0,zero

which stores arguments that are never going to be used on the stack frame.

Move mm_isBranchInstr() from cp1emu.c to branch.c, then split mm_isBranchInstr()
into a __mm_isBranchInstr() core and a mm_isBranchInstr() wrapper inline function
which only invokes __mm_isBranchInstr() on microMIPS configurations.

This shaves off 112 bytes off the kernel and improves code flow a bit.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Cleanup coding style.

o Only define variables in the outermost block
o One empty line at most
o Format comments as per CodingStyle
o Update FSF address in licensing term comment
o Spell FPU and MIPS in all capitals.
o Remove ####-type of lines in comments.
o Try to make things a bit most consistent between sp_*.c / dp_*.c files.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Convert debug printks to pr_debug getting.

And another bunch of #ifdefs bite the dust.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Remove most ifdefery.

Most of these tests should be runtime tests. This also finally means
that on a MIPS III systems MIPS IV opcodes are going to result in an
exception as they're supposed to.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Reformat code according to coding style.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Move all debug fs code to a separate file.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Header file weeding.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Use helpers to manipulate CAUSEF_BD flag.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Get rid of typedefs.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Clear upper bits of FP registers on emulator writes

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>

MIPS: Simplify FP context access

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>

MIPS: math-emu: Fix prefx detection and COP1X function field definition

When running applications which contain the instruction "prefx" on FPU-less
CPUs, a message "Illegal instruction" will be seen. This instruction is
supposed to be ignored by the FPU emulator. However, its current detection
and function field encoding are incorrect. This patch fix the issue.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Steven.Hill@imgtec.com
Patchwork: https://patchwork.linux-mips.org/patch/6608/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Support for 64-bit FP with O32 binaries

CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.

With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.

Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: microMIPS: mfhc1 & mthc1 support for the FPU emulator

This patch adds support for microMIPS encodings of the mfhc1 & mthc1
instructions introduced in release 2 of the mips32 & mips64
architectures, converting them to their mips32 equivalents for the FPU
emulator.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6110/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: math-emu: Add mfhc1 & mthc1 support.

This patch adds support for the mfhc1 & mthc1 instructions to the FPU
emulator. These instructions were introduced in release 2 of the MIPS32
& MIPS64 architectures and allow access to the most significant 32 bits
of a 64-bit FP register.

[ralf@linux-mips.org: Fix ifdef hell added by original patch.]

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6112/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Remove unreachable break statements from cp1emu.c

There were many cases of:

return something;
break;

All those break statements are unreachable and thus redundant.

Signed-off-by: David Daney <david.daney@cavium.com>
Reviewed-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5727/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Handle OCTEON BBIT instructions in FPU emulator.

The branch emulation needs to handle the OCTEON BBIT instructions,
otherwise we get SIGILL instead of emulation.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5726/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Don't try to decode microMIPS branch instructions where they cannot exist.

In mm_isBranchInstr() we can short circuit the entire function if
!cpu_has_mmips.

Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5326/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: microMIPS: Floating point support.

Add logic needed to do floating point emulation in microMIPS mode.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Steven J. Hill <Steven. Hill@imgtec.com>

MIPS: Whitespace cleanup.

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix for warning from FPU emulation code

The default implementation of 'cpu_has_fpu' macro calls
smp_processor_id() which causes this warning to be printed when
preemption is enabled:

[ 4.664000] Algorithmics/MIPS FPU Emulator v1.5
[ 4.676000] BUG: using smp_processor_id() in preemptible [00000000] code: ini
[ 4.700000] caller is fpu_emulator_cop1Handler+0x434/0x27b8

This problem got introduced in November 2009 by
af1d2af877ef6c36990671bc86a5b9c5bb50b1da (lmo) [MIPS: Fix emulation of
64-bit FPU on 64-bit CPUs.] rsp. da0bac33413b2888d3623dad3ad19ce76b688f07
(kernel.org) [MIPS: Fix emulation of 64-bit FPU on FPU-less 64-bit CPUs.]
in 2.6.32.

Fixed by rewriting cop1_64bit() to return a constant whenever possible
but most importantly avoid the use pf cpu_has_fpu entirely.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Jayachandran C <jchandra@broadcom.com>
Initial-patch-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: https://patchwork.linux-mips.org/patch/4225/

MIPS Kprobes: Refactor branch emulation

This patch refactors MIPS branch emulation code so as to allow skipping
delay slot instruction in case of branch likely instructions when branch is
not taken. This is useful for keeping the code common for use cases like
kprobes where one would like to handle the branch instructions keeping the
delay slot instuction also in picture for branch likely instructions. Also
allow emulation when instruction to be decoded is not at pt_regs->cp0_epc
as in case of kprobes where pt_regs->cp0_epc points to the breakpoint
instruction.

The patch also exports the function for modules.

Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2913/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

perf: Remove the nmi parameter from the swevent and overflow interface

The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

- hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
the PMI-tail (ARM etc.)
- tracepoint: nmi=0; since tracepoint could be from NMI context.
- software: nmi=[0,1]; some, like the schedule thing cannot
perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

MIPS: Send proper signal and siginfo on FP emulator faults.

We were unconditionally sending SIGBUS with an empty siginfo on FP
emulator faults. This differs from what happens when real floating
point hardware would get a fault.

For most faults we need to send SIGSEGV with the faulting address
filled in in the struct siginfo.

Reported-by: Camm Maguire <camm@maguirefamily.org>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: Camm Maguire <camm@maguirefamily.org>
Patchwork: https://patchwork.linux-mips.org/patch/1727/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: add support for software performance events

Software events are required as part of the measurable stuff by the
Linux performance counter subsystem. Here is the list of events added by
this patch:
PERF_COUNT_SW_PAGE_FAULTS
PERF_COUNT_SW_PAGE_FAULTS_MIN
PERF_COUNT_SW_PAGE_FAULTS_MAJ
PERF_COUNT_SW_ALIGNMENT_FAULTS
PERF_COUNT_SW_EMULATION_FAULTS

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: linux-mips@linux-mips.org
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: jamie.iles@picochip.com
Acked-by: David Daney <ddaney@caviumnetworks.com>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
Patchwork: https://patchwork.linux-mips.org/patch/1686/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Update broken web addresses in arch directory.

The patch below updates broken web addresses in the arch directory.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Finn Thain <fthain@telegraphics.com.au>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Reviewed-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

MIPS: Coding style cleanups of access of FCSR rounding mode bits

Replaces references to the magic number 0x3 with constants and macros
indicating the real purpose of those bits. They are the rounding mode
bits of the FCSR register.

Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
To: anemo@mba.ocn.ne.jp
To: kevink@paralogos.com
To: linux-mips@linux-mips.org
To: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/1206/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS FPU emulator: allow Cause bits of FCSR to be writeable by ctc1

In the FPU emulator code of the MIPS, the Cause bits of the FCSR register
are not currently writeable by the ctc1 instruction. In odd corner cases,
this can cause problems. For example, a case existed where a divide-by-zero
exception was generated by the FPU, and the signal handler attempted to
restore the FPU registers to their state before the exception occurred. In
this particular setup, writing the old value to the FCSR register would
cause another divide-by-zero exception to occur immediately. The solution
is to change the ctc1 instruction emulator code to allow the Cause bits of
the FCSR register to be writeable. This is the behaviour of the hardware
that the code is emulating.

This problem was found by Shane McDonald, but the credit for the fix goes
to Kevin Kissell. In Kevin's words:

I submit that the bug is indeed in that ctc_op: case of the emulator. The
Cause bits (17:12) are supposed to be writable by that instruction, but the
CTC1 emulation won't let them be updated by the instruction. I think that
actually if you just completely removed lines 387-388 [...] things would
work a good deal better. At least, it would be a more accurate emulation of
the architecturally defined FPU. If I wanted to be really, really pedantic
(which I sometimes do), I'd also protect the reserved bits that aren't
necessarily writable.

Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
To: anemo@mba.ocn.ne.jp
To: kevink@paralogos.com
To: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/1205/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---

MIPS: Collect FPU emulator statistics per-CPU.

On SMP systems, the collection of statistics can cause cache line
bouncing in the lines associated with the counters. Also there are
races incrementing the counters on multiple CPUs.

To fix both problems, we collect the statistics in per-CPU variables,
and add them up in the debugfs read operation.

As a test I ran the LTP float_bessel test on a 12 CPU Octeon system.

Without CONFIG_DEBUG_FS : 2602 seconds.
With CONFIG_DEBUG_FS: 2640 seconds.
With non-cpu-local atomic statistics: 14569 seconds.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix emulation of 64-bit FPU on FPU-less 64-bit CPUs.

Running a 64-bit kernel on a 64-bit CPU without an FPU would cause the
emulator to run in 32-bit mode. The c0_Status.FR bit is wired to zero
on systems without an FPU, so using that bit to decide how the emulator
behaves doesn't allow for proper emulation on 64-bit FPU-less
processors.

Instead, we need to select the emulator mode based on the user-space
ABI. Since the thread flag TIF_32BIT_REGS is used to set c0_Status.FR,
we can just use it to decide if the emulator should be in 32-bit or
64-bit mode.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Switch FPU emulator trap to BREAK instruction.

Arguably using the address error handler has always been ugly. But with
processors that handle unaligned loads and stores in hardware the
current mechanism ceases to work so switch it to a BREAK instruction and
allocate break code 514 to the FPU emulator.

Yoichi Yuasa provided a build fix for CONFIG_BUG=n.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>

MIPS: Fix debugfs_create_*'s error checking method for arch/mips/math-emu/

debugfs_create_*() returns NULL on error. Make its caller debugfs_fpuemu
return -ENODEV on error.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] checkfiles: Fix "need space after that ','" errors.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] Fix "no space between function name and open parenthesis" warnings.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] math-emu minor cleanup

Declaring emulpc and contpc as "unsigned long" can get rid of some casts.
This also get rid of some sparse warnings.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] Add debugfs files to show fpuemu statistics

Export contents of struct mips_fpu_emulator_stats via debugfs.

There is no way to read these statistics for now but they (at least
the "emulated" count) might be sometimes useful for performance tuning
on FPU-less CPUs.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] Make sure cpu_has_fpu is used only in atomic context

Make sure cpu_has_fpu (which uses smp_processor_id()) is used only in
atomic context.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[MIPS] Unify mips_fpu_soft_struct and mips_fpu_hard_structs.

The struct mips_fpu_soft_struct and mips_fpu_hard_struct are
completely same now and the kernel fpu emulator assumes that. This
patch unifies them to mips_fpu_struct and get rid of mips_fpu_union.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Get rid of SINGLE_ONLY_FPU. Linux does not support half FPU other than
by emulation of a full FPU.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Fix all the get_user / put_user related sparse warnings.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

FPU emulator garbage collection.

First argument of fpu_emulator_cop1Handler() was unused.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

GCC bulletproofing: __mips64 is only defined when compiling for 64-bit
processors.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Now that a struct is the only member left in struct
mips_fpu_emulator_stats cleanup that unnecessary nesting of structs.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Fix preemption and SMP problems in the FP emulator code.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Gross macro abuse. Get rid of gpreg_t, vaddr_t, REG_TO_VA and
VA_TO_REG. Who ever wrote this apparently did enjoy the C Puzzle Book.
ISBN 0201604612, a little old but still fun reading for the next
blackout ;)

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

[PATCH] mips: fix build warnings

This patch has fixed the following warnings.

arch/mips/kernel/genex.S:250:5: warning: "CONFIG_64BIT" is not defined
arch/mips/math-emu/cp1emu.c:1128:5: warning: "__mips64" is not defined
arch/mips/math-emu/cp1emu.c:1206:5: warning: "__mips64" is not defined
arch/mips/math-emu/cp1emu.c:1270:5: warning: "__mips64" is not defined
arch/mips/math-emu/cp1emu.c:323:5: warning: "__mips64" is not defined
arch/mips/math-emu/cp1emu.c:808:5: warning: "__mips64" is not defined
arch/mips/math-emu/cp1emu.c:953:5: warning: "__mips64" is not defined
arch/mips/mm/tlbex.c:519:5: warning: "CONFIG_64BIT" is not defined
include/asm/reg.h:73:5: warning: "CONFIG_64BIT" is not defined

Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!