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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 13:40:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 13:40:17 -0700
commitbbce2ad2d711c12d93145a7bbdf086e73f414bcd (patch)
tree35432a39f68f4c5df44ed38037cbf05adadb923e /crypto/jitterentropy-kcapi.c
parent0f776dc377f6c87f4e4d4a5f63602f33fb93b31e (diff)
parent0f95e2ffc58f5d32a90eb1051d17aeebc21cf91d (diff)
Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu: "Here is the crypto update for 4.8: API: - first part of skcipher low-level conversions - add KPP (Key-agreement Protocol Primitives) interface. Algorithms: - fix IPsec/cryptd reordering issues that affects aesni - RSA no longer does explicit leading zero removal - add SHA3 - add DH - add ECDH - improve DRBG performance by not doing CTR by hand Drivers: - add x86 AVX2 multibuffer SHA256/512 - add POWER8 optimised crc32c - add xts support to vmx - add DH support to qat - add RSA support to caam - add Layerscape support to caam - add SEC1 AEAD support to talitos - improve performance by chaining requests in marvell/cesa - add support for Araneus Alea I USB RNG - add support for Broadcom BCM5301 RNG - add support for Amlogic Meson RNG - add support Broadcom NSP SoC RNG" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (180 commits) crypto: vmx - Fix aes_p8_xts_decrypt build failure crypto: vmx - Ignore generated files crypto: vmx - Adding support for XTS crypto: vmx - Adding asm subroutines for XTS crypto: skcipher - add comment for skcipher_alg->base crypto: testmgr - Print akcipher algorithm name crypto: marvell - Fix wrong flag used for GFP in mv_cesa_dma_add_iv_op crypto: nx - off by one bug in nx_of_update_msc() crypto: rsa-pkcs1pad - fix rsa-pkcs1pad request struct crypto: scatterwalk - Inline start/map/done crypto: scatterwalk - Remove unnecessary BUG in scatterwalk_start crypto: scatterwalk - Remove unnecessary advance in scatterwalk_pagedone crypto: scatterwalk - Fix test in scatterwalk_done crypto: api - Optimise away crypto_yield when hard preemption is on crypto: scatterwalk - add no-copy support to copychunks crypto: scatterwalk - Remove scatterwalk_bytes_sglen crypto: omap - Stop using crypto scatterwalk_bytes_sglen crypto: skcipher - Remove top-level givcipher interface crypto: user - Remove crypto_lookup_skcipher call crypto: cts - Convert to skcipher ...
Diffstat (limited to 'crypto/jitterentropy-kcapi.c')
-rw-r--r--crypto/jitterentropy-kcapi.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
index 597cedd3531c..c4938497eedb 100644
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -87,24 +87,28 @@ void jent_memcpy(void *dest, const void *src, unsigned int n)
memcpy(dest, src, n);
}
+/*
+ * Obtain a high-resolution time stamp value. The time stamp is used to measure
+ * the execution time of a given code path and its variations. Hence, the time
+ * stamp must have a sufficiently high resolution.
+ *
+ * Note, if the function returns zero because a given architecture does not
+ * implement a high-resolution time stamp, the RNG code's runtime test
+ * will detect it and will not produce output.
+ */
void jent_get_nstime(__u64 *out)
{
- struct timespec ts;
__u64 tmp = 0;
tmp = random_get_entropy();
/*
- * If random_get_entropy does not return a value (which is possible on,
- * for example, MIPS), invoke __getnstimeofday
+ * If random_get_entropy does not return a value, i.e. it is not
+ * implemented for a given architecture, use a clock source.
* hoping that there are timers we can work with.
*/
- if ((0 == tmp) &&
- (0 == __getnstimeofday(&ts))) {
- tmp = ts.tv_sec;
- tmp = tmp << 32;
- tmp = tmp | ts.tv_nsec;
- }
+ if (tmp == 0)
+ tmp = ktime_get_ns();
*out = tmp;
}