linux-toradex.git/lib/mpi/longlong.h, branch v5.0

lib/mpi: Fix umul_ppmm() for MIPS64r6

2017-12-22T08:39:09+00:00

Current MIPS64r6 toolchains aren't able to generate efficient
DMULU/DMUHU based code for the C implementation of umul_ppmm(), which
performs an unsigned 64 x 64 bit multiply and returns the upper and
lower 64-bit halves of the 128-bit result. Instead it widens the 64-bit
inputs to 128-bits and emits a __multi3 intrinsic call to perform a 128
x 128 multiply. This is both inefficient, and it results in a link error
since we don't include __multi3 in MIPS linux.

For example commit 90a53e4432b1 ("cfg80211: implement regdb signature
checking") merged in v4.15-rc1 recently broke the 64r6_defconfig and
64r6el_defconfig builds by indirectly selecting MPILIB. The same build
errors can be reproduced on older kernels by enabling e.g. CRYPTO_RSA:

lib/mpi/generic_mpih-mul1.o: In function `mpihelp_mul_1':
lib/mpi/generic_mpih-mul1.c:50: undefined reference to `__multi3'
lib/mpi/generic_mpih-mul2.o: In function `mpihelp_addmul_1':
lib/mpi/generic_mpih-mul2.c:49: undefined reference to `__multi3'
lib/mpi/generic_mpih-mul3.o: In function `mpihelp_submul_1':
lib/mpi/generic_mpih-mul3.c:49: undefined reference to `__multi3'
lib/mpi/mpih-div.o In function `mpihelp_divrem':
lib/mpi/mpih-div.c:205: undefined reference to `__multi3'
lib/mpi/mpih-div.c:142: undefined reference to `__multi3'

Therefore add an efficient MIPS64r6 implementation of umul_ppmm() using
inline assembly and the DMULU/DMUHU instructions, to prevent __multi3
calls being emitted.

Fixes: 7fd08ca58ae6 ("MIPS: Add build support for the MIPS R6 ISA")
Signed-off-by: James Hogan 
Cc: Ralf Baechle 
Cc: Herbert Xu 
Cc: "David S. Miller" 
Cc: linux-mips@linux-mips.org
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Herbert Xu

lib/mpi: fix build with clang

2017-08-17T08:53:31+00:00

Use just @ to denote comments which works with gcc and clang.
Otherwise clang reports an escape sequence error:
  error: invalid % escape in inline assembly string

Use %0-%3 as operand references, this avoids:
  error: invalid operand in inline asm: 'umull ${1:r}, ${0:r}, ${2:r}, ${3:r}'

Also remove superfluous casts on output operands to avoid warnings
such as:
  warning: invalid use of a cast in an inline asm context requiring an l-value

Signed-off-by: Stefan Agner 
Acked-by: Arnd Bergmann 
Signed-off-by: Herbert Xu

lib/mpi: avoid assembler warning

2016-02-27T19:26:34+00:00

A wrapper around the umull assembly instruction might reuse
the input register as an output, which is undefined on
some ARM machines, as pointed out by this assembler warning:

  CC      lib/mpi/generic_mpih-mul1.o
/tmp/ccxJuxIy.s: Assembler messages:
/tmp/ccxJuxIy.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul2.o
/tmp/ccI0scAD.s: Assembler messages:
/tmp/ccI0scAD.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul3.o
/tmp/ccMvVQcp.s: Assembler messages:
/tmp/ccMvVQcp.s:53: rdhi, rdlo and rm must all be different

This changes the constraints to force different registers to
be used as output.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Herbert Xu

move count_zeroes.h out of asm-generic

2015-10-14T22:21:07+00:00

This header contains a few helpers currenly only used by the mpi
implementation, and not default implementation of architecture code.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Arnd Bergmann

MPI: MIPS: Fix compilation error with GCC 5.1

2015-06-13T09:36:41+00:00

This patch fixes mips compilation error:

lib/mpi/generic_mpih-mul1.c: In function 'mpihelp_mul_1':
lib/mpi/longlong.h:651:2: error: impossible constraint in 'asm'

Signed-off-by: Jaedon Shin 
Cc: Linux-MIPS 
Patchwork: https://patchwork.linux-mips.org/patch/10546/
Signed-off-by: Ralf Baechle

alpha: Modernize lib/mpi/longlong.h

2013-07-19T20:54:23+00:00

Remove the compile warning for __udiv_qrnnd not having a prototype.
Use the __builtin_alpha_umulh introduced in gcc 4.0.

Reviewed-and-Tested-by: Matt Turner 
Signed-off-by: Matt Turner 
Signed-off-by: Richard Henderson

MPILIB: disable usage of floating point registers on parisc

2013-05-24T20:30:11+00:00

The umul_ppmm() macro for parisc uses the xmpyu assembler statement
which does calculation via a floating point register.

But usage of floating point registers inside the Linux kernel are not
allowed and gcc will stop compilation due to the -mdisable-fpregs
compiler option.

Fix this by disabling the umul_ppmm() and udiv_qrnnd() macros. The
mpilib will then use the generic built-in implementations instead.

Signed-off-by: Helge Deller

MPI: Fix compilation on MIPS with GCC 4.4 and newer

2012-11-23T17:57:17+00:00

Since 4.4 GCC on MIPS no longer recognizes the "h" constraint,
leading to this build failure:

  CC      lib/mpi/generic_mpih-mul1.o
lib/mpi/generic_mpih-mul1.c: In function 'mpihelp_mul_1':
lib/mpi/generic_mpih-mul1.c:50:3: error: impossible constraint in 'asm'

This patch updates MPI with the latest umul_ppm implementations for MIPS.

Signed-off-by: Manuel Lauss 
Cc: Linux-MIPS 
Cc: Dmitry Kasatkin 
Cc: James Morris 
Patchwork: https://patchwork.linux-mips.org/patch/4612/
Signed-off-by: Ralf Baechle

MPILIB: Provide count_leading/trailing_zeros() based on arch functions

2012-10-08T03:20:11+00:00

Provide count_leading/trailing_zeros() macros based on extant arch bit scanning
functions rather than reimplementing from scratch in MPILIB.

Whilst we're at it, turn count_foo_zeros(n, x) into n = count_foo_zeros(x).

Also move the definition to asm-generic as other people may be interested in
using it.

Signed-off-by: David Howells 
Cc: David S. Miller 
Cc: Dmitry Kasatkin 
Cc: Arnd Bergmann 
Signed-off-by: Rusty Russell

lib: Fix 32-bit sparc udiv_qrnnd() definition in mpilib's longlong.h

2012-02-01T23:34:25+00:00

This copy of longlong.h is extremely dated and results in compile
errors on sparc32 when MPILIB is enabled, copy over the more uptodate
implementation from arch/sparc/math/sfp-util_32.h

Reported-by: Al Viro 
Signed-off-by: David S. Miller 
Signed-off-by: James Morris