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-rw-r--r--crypto/Kconfig43
1 files changed, 43 insertions, 0 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 650b1b3620d8..00c827d9f0d2 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1296,6 +1296,49 @@ config CRYPTO_JITTERENTROPY
See https://www.chronox.de/jent.html
+choice
+ prompt "CPU Jitter RNG Memory Size"
+ default CRYPTO_JITTERENTROPY_MEMSIZE_2
+ depends on CRYPTO_JITTERENTROPY
+ help
+ The Jitter RNG measures the execution time of memory accesses.
+ Multiple consecutive memory accesses are performed. If the memory
+ size fits into a cache (e.g. L1), only the memory access timing
+ to that cache is measured. The closer the cache is to the CPU
+ the less variations are measured and thus the less entropy is
+ obtained. Thus, if the memory size fits into the L1 cache, the
+ obtained entropy is less than if the memory size fits within
+ L1 + L2, which in turn is less if the memory fits into
+ L1 + L2 + L3. Thus, by selecting a different memory size,
+ the entropy rate produced by the Jitter RNG can be modified.
+
+ config CRYPTO_JITTERENTROPY_MEMSIZE_2
+ bool "2048 Bytes (default)"
+
+ config CRYPTO_JITTERENTROPY_MEMSIZE_128
+ bool "128 kBytes"
+
+ config CRYPTO_JITTERENTROPY_MEMSIZE_1024
+ bool "1024 kBytes"
+
+ config CRYPTO_JITTERENTROPY_MEMSIZE_8192
+ bool "8192 kBytes"
+endchoice
+
+config CRYPTO_JITTERENTROPY_MEMORY_BLOCKS
+ int
+ default 64 if CRYPTO_JITTERENTROPY_MEMSIZE_2
+ default 512 if CRYPTO_JITTERENTROPY_MEMSIZE_128
+ default 1024 if CRYPTO_JITTERENTROPY_MEMSIZE_1024
+ default 4096 if CRYPTO_JITTERENTROPY_MEMSIZE_8192
+
+config CRYPTO_JITTERENTROPY_MEMORY_BLOCKSIZE
+ int
+ default 32 if CRYPTO_JITTERENTROPY_MEMSIZE_2
+ default 256 if CRYPTO_JITTERENTROPY_MEMSIZE_128
+ default 1024 if CRYPTO_JITTERENTROPY_MEMSIZE_1024
+ default 2048 if CRYPTO_JITTERENTROPY_MEMSIZE_8192
+
config CRYPTO_JITTERENTROPY_TESTINTERFACE
bool "CPU Jitter RNG Test Interface"
depends on CRYPTO_JITTERENTROPY