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authorDmitry Kasatkin <d.kasatkin@samsung.com>2014-02-26 17:05:20 +0200
committerMimi Zohar <zohar@linux.vnet.ibm.com>2014-07-17 09:35:10 -0400
commit3bcced39ea7d1b0da0a991e221f53de480c6b60b (patch)
treea45834814cd073987f9605b616e7b8dd094d94fd /Documentation/kernel-parameters.txt
parent7e9001f663636116fdc2ea7978f0350849ced624 (diff)
ima: use ahash API for file hash calculation
Async hash API allows the use of HW acceleration for hash calculation. It may give significant performance gain and/or reduce power consumption, which might be very beneficial for battery powered devices. This patch introduces hash calculation using ahash API. ahash performance depends on the data size and the particular HW. Depending on the specific system, shash performance may be better. This patch defines 'ahash_minsize' module parameter, which is used to define the minimal file size to use with ahash. If this minimum file size is not set or the file is smaller than defined by the parameter, shash will be used. Changes in v3: - kernel parameter replaced with module parameter - pr_crit replaced with pr_crit_ratelimited - more comment changes - Mimi Changes in v2: - ima_ahash_size became as ima_ahash - ahash pre-allocation moved out from __init code to be able to use ahash crypto modules. Ahash allocated once on the first use. - hash calculation falls back to shash if ahash allocation/calculation fails - complex initialization separated from variable declaration - improved comments Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1b9aa8c5a52..775fe039e060 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1313,6 +1313,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Formats: { "ima" | "ima-ng" }
Default: "ima-ng"
+ ima.ahash_minsize= [IMA] Minimum file size for asynchronous hash usage
+ Format: <min_file_size>
+ Set the minimal file size for using asynchronous hash.
+ If left unspecified, ahash usage is disabled.
+
+ ahash performance varies for different data sizes on
+ different crypto accelerators. This option can be used
+ to achieve the best performance for a particular HW.
+
init= [KNL]
Format: <full_path>
Run specified binary instead of /sbin/init as init

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