path: root/Documentation/s390
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authorJan Glauber <jan.glauber@de.ibm.com>2007-04-27 16:01:54 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-04-27 16:01:46 +0200
commit131a395c18af43d824841642038e5cc0d48f0bd2 (patch)
treec3fec61634deee0589e3a0fa3aec0a63803f3815 /Documentation/s390
parent6d4740c89c187ee8f5ac7355c4eeffda26493d1f (diff)
[S390] crypto: cleanup.
Cleanup code and remove obsolete documentation. Signed-off-by: Jan Glauber <jan.glauber@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'Documentation/s390')
1 files changed, 0 insertions, 83 deletions
diff --git a/Documentation/s390/crypto/crypto-API.txt b/Documentation/s390/crypto/crypto-API.txt
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--- a/Documentation/s390/crypto/crypto-API.txt
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-crypto-API support for z990 Message Security Assist (MSA) instructions
-AUTHOR: Thomas Spatzier (tspat@de.ibm.com)
-1. Introduction crypto-API
-See Documentation/crypto/api-intro.txt for an introduction/description of the
-kernel crypto API.
-According to api-intro.txt support for z990 crypto instructions has been added
-in the algorithm api layer of the crypto API. Several files containing z990
-optimized implementations of crypto algorithms are placed in the
-arch/s390/crypto directory.
-2. Probing for availability of MSA
-It should be possible to use Kernels with the z990 crypto implementations both
-on machines with MSA available and on those without MSA (pre z990 or z990
-without MSA). Therefore a simple probing mechanism has been implemented:
-In the init function of each crypto module the availability of MSA and of the
-respective crypto algorithm in particular will be tested. If the algorithm is
-available the module will load and register its algorithm with the crypto API.
-If the respective crypto algorithm is not available, the init function will
-return -ENOSYS. In that case a fallback to the standard software implementation
-of the crypto algorithm must be taken ( -> the standard crypto modules are
-also built when compiling the kernel).
-3. Ensuring z990 crypto module preference
-If z990 crypto instructions are available the optimized modules should be
-preferred instead of standard modules.
-3.1. compiled-in modules
-For compiled-in modules it has to be ensured that the z990 modules are linked
-before the standard crypto modules. Then, on system startup the init functions
-of z990 crypto modules will be called first and query for availability of z990
-crypto instructions. If instruction is available, the z990 module will register
-its crypto algorithm implementation -> the load of the standard module will fail
-since the algorithm is already registered.
-If z990 crypto instruction is not available the load of the z990 module will
-fail -> the standard module will load and register its algorithm.
-3.2. dynamic modules
-A system administrator has to take care of giving preference to z990 crypto
-modules. If MSA is available appropriate lines have to be added to
-Example: z990 crypto instruction for SHA1 algorithm is available
- add the following line to /etc/modprobe.conf (assuming the
- z990 crypto modules for SHA1 is called sha1_z990):
- alias sha1 sha1_z990
- -> when the sha1 algorithm is requested through the crypto API
- (which has a module autoloader) the z990 module will be loaded.
-TBD: a userspace module probing mechanism
- something like 'probe sha1 sha1_z990 sha1' in modprobe.conf
- -> try module sha1_z990, if it fails to load standard module sha1
- the 'probe' statement is currently not supported in modprobe.conf
-4. Currently implemented z990 crypto algorithms
-The following crypto algorithms with z990 MSA support are currently implemented.
-The name of each algorithm under which it is registered in crypto API and the
-name of the respective module is given in square brackets.
-- SHA1 Digest Algorithm [sha1 -> sha1_z990]
-- DES Encrypt/Decrypt Algorithm (64bit key) [des -> des_z990]
-- Triple DES Encrypt/Decrypt Algorithm (128bit key) [des3_ede128 -> des_z990]
-- Triple DES Encrypt/Decrypt Algorithm (192bit key) [des3_ede -> des_z990]
-In order to load, for example, the sha1_z990 module when the sha1 algorithm is
-requested (see 3.2.) add 'alias sha1 sha1_z990' to /etc/modprobe.conf.

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