diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-13 08:50:16 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-13 08:50:16 -0700 |
commit | 39a5101f989e8d2be557136704d53990f9b402c8 (patch) | |
tree | b9c16c6f32508939111fb6d0159d7450713a5f33 /lib/mpi/mpih-div.c | |
parent | 865c50e1d279671728c2936cb7680eb89355eeea (diff) | |
parent | 3093e7c16e12d729c325adb3c53dde7308cefbd8 (diff) |
Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"API:
- Allow DRBG testing through user-space af_alg
- Add tcrypt speed testing support for keyed hashes
- Add type-safe init/exit hooks for ahash
Algorithms:
- Mark arc4 as obsolete and pending for future removal
- Mark anubis, khazad, sead and tea as obsolete
- Improve boot-time xor benchmark
- Add OSCCA SM2 asymmetric cipher algorithm and use it for integrity
Drivers:
- Fixes and enhancement for XTS in caam
- Add support for XIP8001B hwrng in xiphera-trng
- Add RNG and hash support in sun8i-ce/sun8i-ss
- Allow imx-rngc to be used by kernel entropy pool
- Use crypto engine in omap-sham
- Add support for Ingenic X1830 with ingenic"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (205 commits)
X.509: Fix modular build of public_key_sm2
crypto: xor - Remove unused variable count in do_xor_speed
X.509: fix error return value on the failed path
crypto: bcm - Verify GCM/CCM key length in setkey
crypto: qat - drop input parameter from adf_enable_aer()
crypto: qat - fix function parameters descriptions
crypto: atmel-tdes - use semicolons rather than commas to separate statements
crypto: drivers - use semicolons rather than commas to separate statements
hwrng: mxc-rnga - use semicolons rather than commas to separate statements
hwrng: iproc-rng200 - use semicolons rather than commas to separate statements
hwrng: stm32 - use semicolons rather than commas to separate statements
crypto: xor - use ktime for template benchmarking
crypto: xor - defer load time benchmark to a later time
crypto: hisilicon/zip - fix the uninitalized 'curr_qm_qp_num'
crypto: hisilicon/zip - fix the return value when device is busy
crypto: hisilicon/zip - fix zero length input in GZIP decompress
crypto: hisilicon/zip - fix the uncleared debug registers
lib/mpi: Fix unused variable warnings
crypto: x86/poly1305 - Remove assignments with no effect
hwrng: npcm - modify readl to readb
...
Diffstat (limited to 'lib/mpi/mpih-div.c')
-rw-r--r-- | lib/mpi/mpih-div.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/lib/mpi/mpih-div.c b/lib/mpi/mpih-div.c index 913a519eb005..be70ee2e42d3 100644 --- a/lib/mpi/mpih-div.c +++ b/lib/mpi/mpih-div.c @@ -24,6 +24,150 @@ #define UDIV_TIME UMUL_TIME #endif + +mpi_limb_t +mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, + mpi_limb_t divisor_limb) +{ + mpi_size_t i; + mpi_limb_t n1, n0, r; + mpi_limb_t dummy __maybe_unused; + + /* Botch: Should this be handled at all? Rely on callers? */ + if (!dividend_size) + return 0; + + /* If multiplication is much faster than division, and the + * dividend is large, pre-invert the divisor, and use + * only multiplications in the inner loop. + * + * This test should be read: + * Does it ever help to use udiv_qrnnd_preinv? + * && Does what we save compensate for the inversion overhead? + */ + if (UDIV_TIME > (2 * UMUL_TIME + 6) + && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) { + int normalization_steps; + + normalization_steps = count_leading_zeros(divisor_limb); + if (normalization_steps) { + mpi_limb_t divisor_limb_inverted; + + divisor_limb <<= normalization_steps; + + /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The + * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the + * most significant bit (with weight 2**N) implicit. + * + * Special case for DIVISOR_LIMB == 100...000. + */ + if (!(divisor_limb << 1)) + divisor_limb_inverted = ~(mpi_limb_t)0; + else + udiv_qrnnd(divisor_limb_inverted, dummy, + -divisor_limb, 0, divisor_limb); + + n1 = dividend_ptr[dividend_size - 1]; + r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); + + /* Possible optimization: + * if (r == 0 + * && divisor_limb > ((n1 << normalization_steps) + * | (dividend_ptr[dividend_size - 2] >> ...))) + * ...one division less... + */ + for (i = dividend_size - 2; i >= 0; i--) { + n0 = dividend_ptr[i]; + UDIV_QRNND_PREINV(dummy, r, r, + ((n1 << normalization_steps) + | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), + divisor_limb, divisor_limb_inverted); + n1 = n0; + } + UDIV_QRNND_PREINV(dummy, r, r, + n1 << normalization_steps, + divisor_limb, divisor_limb_inverted); + return r >> normalization_steps; + } else { + mpi_limb_t divisor_limb_inverted; + + /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The + * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the + * most significant bit (with weight 2**N) implicit. + * + * Special case for DIVISOR_LIMB == 100...000. + */ + if (!(divisor_limb << 1)) + divisor_limb_inverted = ~(mpi_limb_t)0; + else + udiv_qrnnd(divisor_limb_inverted, dummy, + -divisor_limb, 0, divisor_limb); + + i = dividend_size - 1; + r = dividend_ptr[i]; + + if (r >= divisor_limb) + r = 0; + else + i--; + + for ( ; i >= 0; i--) { + n0 = dividend_ptr[i]; + UDIV_QRNND_PREINV(dummy, r, r, + n0, divisor_limb, divisor_limb_inverted); + } + return r; + } + } else { + if (UDIV_NEEDS_NORMALIZATION) { + int normalization_steps; + + normalization_steps = count_leading_zeros(divisor_limb); + if (normalization_steps) { + divisor_limb <<= normalization_steps; + + n1 = dividend_ptr[dividend_size - 1]; + r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); + + /* Possible optimization: + * if (r == 0 + * && divisor_limb > ((n1 << normalization_steps) + * | (dividend_ptr[dividend_size - 2] >> ...))) + * ...one division less... + */ + for (i = dividend_size - 2; i >= 0; i--) { + n0 = dividend_ptr[i]; + udiv_qrnnd(dummy, r, r, + ((n1 << normalization_steps) + | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), + divisor_limb); + n1 = n0; + } + udiv_qrnnd(dummy, r, r, + n1 << normalization_steps, + divisor_limb); + return r >> normalization_steps; + } + } + /* No normalization needed, either because udiv_qrnnd doesn't require + * it, or because DIVISOR_LIMB is already normalized. + */ + i = dividend_size - 1; + r = dividend_ptr[i]; + + if (r >= divisor_limb) + r = 0; + else + i--; + + for (; i >= 0; i--) { + n0 = dividend_ptr[i]; + udiv_qrnnd(dummy, r, r, n0, divisor_limb); + } + return r; + } +} + /* Divide num (NP/NSIZE) by den (DP/DSIZE) and write * the NSIZE-DSIZE least significant quotient limbs at QP * and the DSIZE long remainder at NP. If QEXTRA_LIMBS is @@ -221,3 +365,153 @@ q_test: return most_significant_q_limb; } + +/**************** + * Divide (DIVIDEND_PTR,,DIVIDEND_SIZE) by DIVISOR_LIMB. + * Write DIVIDEND_SIZE limbs of quotient at QUOT_PTR. + * Return the single-limb remainder. + * There are no constraints on the value of the divisor. + * + * QUOT_PTR and DIVIDEND_PTR might point to the same limb. + */ + +mpi_limb_t +mpihelp_divmod_1(mpi_ptr_t quot_ptr, + mpi_ptr_t dividend_ptr, mpi_size_t dividend_size, + mpi_limb_t divisor_limb) +{ + mpi_size_t i; + mpi_limb_t n1, n0, r; + mpi_limb_t dummy __maybe_unused; + + if (!dividend_size) + return 0; + + /* If multiplication is much faster than division, and the + * dividend is large, pre-invert the divisor, and use + * only multiplications in the inner loop. + * + * This test should be read: + * Does it ever help to use udiv_qrnnd_preinv? + * && Does what we save compensate for the inversion overhead? + */ + if (UDIV_TIME > (2 * UMUL_TIME + 6) + && (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) { + int normalization_steps; + + normalization_steps = count_leading_zeros(divisor_limb); + if (normalization_steps) { + mpi_limb_t divisor_limb_inverted; + + divisor_limb <<= normalization_steps; + + /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The + * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the + * most significant bit (with weight 2**N) implicit. + */ + /* Special case for DIVISOR_LIMB == 100...000. */ + if (!(divisor_limb << 1)) + divisor_limb_inverted = ~(mpi_limb_t)0; + else + udiv_qrnnd(divisor_limb_inverted, dummy, + -divisor_limb, 0, divisor_limb); + + n1 = dividend_ptr[dividend_size - 1]; + r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); + + /* Possible optimization: + * if (r == 0 + * && divisor_limb > ((n1 << normalization_steps) + * | (dividend_ptr[dividend_size - 2] >> ...))) + * ...one division less... + */ + for (i = dividend_size - 2; i >= 0; i--) { + n0 = dividend_ptr[i]; + UDIV_QRNND_PREINV(quot_ptr[i + 1], r, r, + ((n1 << normalization_steps) + | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), + divisor_limb, divisor_limb_inverted); + n1 = n0; + } + UDIV_QRNND_PREINV(quot_ptr[0], r, r, + n1 << normalization_steps, + divisor_limb, divisor_limb_inverted); + return r >> normalization_steps; + } else { + mpi_limb_t divisor_limb_inverted; + + /* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB. The + * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the + * most significant bit (with weight 2**N) implicit. + */ + /* Special case for DIVISOR_LIMB == 100...000. */ + if (!(divisor_limb << 1)) + divisor_limb_inverted = ~(mpi_limb_t) 0; + else + udiv_qrnnd(divisor_limb_inverted, dummy, + -divisor_limb, 0, divisor_limb); + + i = dividend_size - 1; + r = dividend_ptr[i]; + + if (r >= divisor_limb) + r = 0; + else + quot_ptr[i--] = 0; + + for ( ; i >= 0; i--) { + n0 = dividend_ptr[i]; + UDIV_QRNND_PREINV(quot_ptr[i], r, r, + n0, divisor_limb, divisor_limb_inverted); + } + return r; + } + } else { + if (UDIV_NEEDS_NORMALIZATION) { + int normalization_steps; + + normalization_steps = count_leading_zeros(divisor_limb); + if (normalization_steps) { + divisor_limb <<= normalization_steps; + + n1 = dividend_ptr[dividend_size - 1]; + r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps); + + /* Possible optimization: + * if (r == 0 + * && divisor_limb > ((n1 << normalization_steps) + * | (dividend_ptr[dividend_size - 2] >> ...))) + * ...one division less... + */ + for (i = dividend_size - 2; i >= 0; i--) { + n0 = dividend_ptr[i]; + udiv_qrnnd(quot_ptr[i + 1], r, r, + ((n1 << normalization_steps) + | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))), + divisor_limb); + n1 = n0; + } + udiv_qrnnd(quot_ptr[0], r, r, + n1 << normalization_steps, + divisor_limb); + return r >> normalization_steps; + } + } + /* No normalization needed, either because udiv_qrnnd doesn't require + * it, or because DIVISOR_LIMB is already normalized. + */ + i = dividend_size - 1; + r = dividend_ptr[i]; + + if (r >= divisor_limb) + r = 0; + else + quot_ptr[i--] = 0; + + for (; i >= 0; i--) { + n0 = dividend_ptr[i]; + udiv_qrnnd(quot_ptr[i], r, r, n0, divisor_limb); + } + return r; + } +} |