kernel/lib/mpi, branch linux-4.1.y

lib/mpi: Fix umul_ppmm() for MIPS64r6

2018-03-21T03:49:45Z

[ Upstream commit bbc25bee37d2b32cf3a1fab9195b6da3a185614a ] 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 Signed-off-by: Sasha Levin

MPI: MIPS: Fix compilation error with GCC 5.1

2015-06-13T09:36:41Z

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

MPILIB: Fix comparison of negative MPIs

2015-01-14T16:10:12Z

If u and v both represent negative integers and their limb counts happen to differ, mpi_cmp will always return a positive value - this is obviously bogus. u is smaller than v if and only if it is larger in absolute value. Signed-off-by: Rasmus Villemoes Signed-off-by: David Howells Acked-by: Dmitry Kasatkin

MPILIB: Fix obvious but harmless typo

2015-01-14T15:16:00Z

The macro MPN_COPY_INCR this occurs in isn't used anywhere. Signed-off-by: Rasmus Villemoes Signed-off-by: David Howells

MPILIB: Deobfuscate mpi_cmp

2015-01-14T15:15:57Z

The condition preceding 'return 1;' makes my head hurt. At this point, we know that u and v have the same sign; if they are negative, they compare opposite to how their absolute values compare (which mpihelp_cmp found for us), otherwise cmp itself is the answer. Negating cmp is ok since mpihelp_cmp returns {-1,0,1}; -INT_MIN==INT_MIN won't bite us. Signed-off-by: Rasmus Villemoes Signed-off-by: David Howells Acked-by: Dmitry Kasatkin

MPILIB: add module description and license

2013-09-25T16:17:01Z

This patch fixes lack of license, otherwise mpi.ko taints kernel. Signed-off-by: Konstantin Khlebnikov Signed-off-by: David Howells

alpha: Modernize lib/mpi/longlong.h

2013-07-19T20:54:23Z

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

lib/mpi/mpicoder.c: looping issue, need stop when equal to zero, found by 'EXTRA_FLAGS=-W'.

2013-06-12T23:29:44Z

For 'while' looping, need stop when 'nbytes == 0', or will cause issue. ('nbytes' is size_t which is always bigger or equal than zero). The related warning: (with EXTRA_CFLAGS=-W) lib/mpi/mpicoder.c:40:2: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] Signed-off-by: Chen Gang Cc: Rusty Russell Cc: David Howells Cc: James Morris Cc: Andy Shevchenko Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

MPILIB: disable usage of floating point registers on parisc

2013-05-24T20:30:11Z

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

mpilib: use DIV_ROUND_UP and remove unused macros

2013-02-01T05:28:32Z

Remove MIN, MAX and ABS macros that are duplicates kernel's native implementation. Signed-off-by: Andy Shevchenko Signed-off-by: James Morris