Commit bbd426f542 "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>
The fix in the preceeding commit did do exactly the same thing in two
places showing some code cleanup was due.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Older GCC doesn't get named initializations of anonymous structs right,
that is members are not initializable in the containing structure through
name however old style initializations are working fine.
The issue exists with gcc up to 4.5.x.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
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>
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>
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>
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>
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>
There are two version of get_rounding(), one for single precision, one
for double precision. Add a ieee754sp_ rsp. ieee754dp_ prefix for
clarity.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
ieee754d.o contains only debug code and dp_sqrt.o and sp_sqrt.o contain
code which for MIPS I/II/III systems we don't want to link. Again the
savings can be considerable for some systems:
$ mips-linux-size --totals ieee754d.o dp_sqrt.o sp_sqrt.o
text data bss dec hex filename
1624 0 0 1624 658 ieee754d.o
2016 0 0 2016 7e0 dp_sqrt.o
736 0 0 736 2e0 sp_sqrt.o
4376 0 0 4376 1118 (TOTALS)
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Both are unused since lmo commit fdffbafbb38723618626c70ffdc6ff9175cdffa2
[Lots of FPU bug fixes from Kjeld Borch Egevang.]
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
LONG_LONG_MAX is a symbol defined in <limits.h> which may not be available
so better rely on something provided by a kernel header. While at it,
turn these function-like macros into inline functions.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
The header file had no include guards; this only happened to work because
the file only contains macro definitions and protypes.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The upper bits of an FP register are architecturally defined as
unpredictable following an instructions which only writes the lower
bits. The prior behaviour of the kernel is to leave them unmodified.
This patch modifies that to clear the upper bits to zero. This is what
the MSA architecture reference manual specifies should happen for its
wider registers and is still permissible for scalar FP instructions
given the bits unpredictability there.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: sergei.shtylyov@cogentembedded.com
Patchwork: https://patchwork.linux-mips.org/patch/6435/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
These functions aren't directly related to the FPU emulator at all, they
simply copy between a thread's saved context & a sigcontext. Thus move
them to the appropriate signal files & rename them accordingly. This
makes it clearer that the functions don't require the FPU emulator in
any way.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6422/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
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>
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>
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>
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>
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>
Paul Burton
Rob Kendrick
Ralf Baechle
David Daney
Deng-Cheng Zhu
Steven J. Hill
Leonid Yegoshin