diff options
author | Jan Glauber <jan.glauber@de.ibm.com> | 2007-04-27 10:01:54 -0400 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-04-27 10:01:46 -0400 |
commit | 131a395c18af43d824841642038e5cc0d48f0bd2 (patch) | |
tree | c3fec61634deee0589e3a0fa3aec0a63803f3815 /Documentation/s390 | |
parent | 6d4740c89c187ee8f5ac7355c4eeffda26493d1f (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')
-rw-r--r-- | Documentation/s390/crypto/crypto-API.txt | 83 |
1 files changed, 0 insertions, 83 deletions
diff --git a/Documentation/s390/crypto/crypto-API.txt b/Documentation/s390/crypto/crypto-API.txt deleted file mode 100644 index 71ae6ca9f2c2..000000000000 --- a/Documentation/s390/crypto/crypto-API.txt +++ /dev/null | |||
@@ -1,83 +0,0 @@ | |||
1 | crypto-API support for z990 Message Security Assist (MSA) instructions | ||
2 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
3 | |||
4 | AUTHOR: Thomas Spatzier (tspat@de.ibm.com) | ||
5 | |||
6 | |||
7 | 1. Introduction crypto-API | ||
8 | ~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
9 | See Documentation/crypto/api-intro.txt for an introduction/description of the | ||
10 | kernel crypto API. | ||
11 | According to api-intro.txt support for z990 crypto instructions has been added | ||
12 | in the algorithm api layer of the crypto API. Several files containing z990 | ||
13 | optimized implementations of crypto algorithms are placed in the | ||
14 | arch/s390/crypto directory. | ||
15 | |||
16 | |||
17 | 2. Probing for availability of MSA | ||
18 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
19 | It should be possible to use Kernels with the z990 crypto implementations both | ||
20 | on machines with MSA available and on those without MSA (pre z990 or z990 | ||
21 | without MSA). Therefore a simple probing mechanism has been implemented: | ||
22 | In the init function of each crypto module the availability of MSA and of the | ||
23 | respective crypto algorithm in particular will be tested. If the algorithm is | ||
24 | available the module will load and register its algorithm with the crypto API. | ||
25 | |||
26 | If the respective crypto algorithm is not available, the init function will | ||
27 | return -ENOSYS. In that case a fallback to the standard software implementation | ||
28 | of the crypto algorithm must be taken ( -> the standard crypto modules are | ||
29 | also built when compiling the kernel). | ||
30 | |||
31 | |||
32 | 3. Ensuring z990 crypto module preference | ||
33 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
34 | If z990 crypto instructions are available the optimized modules should be | ||
35 | preferred instead of standard modules. | ||
36 | |||
37 | 3.1. compiled-in modules | ||
38 | ~~~~~~~~~~~~~~~~~~~~~~~~ | ||
39 | For compiled-in modules it has to be ensured that the z990 modules are linked | ||
40 | before the standard crypto modules. Then, on system startup the init functions | ||
41 | of z990 crypto modules will be called first and query for availability of z990 | ||
42 | crypto instructions. If instruction is available, the z990 module will register | ||
43 | its crypto algorithm implementation -> the load of the standard module will fail | ||
44 | since the algorithm is already registered. | ||
45 | If z990 crypto instruction is not available the load of the z990 module will | ||
46 | fail -> the standard module will load and register its algorithm. | ||
47 | |||
48 | 3.2. dynamic modules | ||
49 | ~~~~~~~~~~~~~~~~~~~~ | ||
50 | A system administrator has to take care of giving preference to z990 crypto | ||
51 | modules. If MSA is available appropriate lines have to be added to | ||
52 | /etc/modprobe.conf. | ||
53 | |||
54 | Example: z990 crypto instruction for SHA1 algorithm is available | ||
55 | |||
56 | add the following line to /etc/modprobe.conf (assuming the | ||
57 | z990 crypto modules for SHA1 is called sha1_z990): | ||
58 | |||
59 | alias sha1 sha1_z990 | ||
60 | |||
61 | -> when the sha1 algorithm is requested through the crypto API | ||
62 | (which has a module autoloader) the z990 module will be loaded. | ||
63 | |||
64 | TBD: a userspace module probing mechanism | ||
65 | something like 'probe sha1 sha1_z990 sha1' in modprobe.conf | ||
66 | -> try module sha1_z990, if it fails to load standard module sha1 | ||
67 | the 'probe' statement is currently not supported in modprobe.conf | ||
68 | |||
69 | |||
70 | 4. Currently implemented z990 crypto algorithms | ||
71 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
72 | The following crypto algorithms with z990 MSA support are currently implemented. | ||
73 | The name of each algorithm under which it is registered in crypto API and the | ||
74 | name of the respective module is given in square brackets. | ||
75 | |||
76 | - SHA1 Digest Algorithm [sha1 -> sha1_z990] | ||
77 | - DES Encrypt/Decrypt Algorithm (64bit key) [des -> des_z990] | ||
78 | - Triple DES Encrypt/Decrypt Algorithm (128bit key) [des3_ede128 -> des_z990] | ||
79 | - Triple DES Encrypt/Decrypt Algorithm (192bit key) [des3_ede -> des_z990] | ||
80 | |||
81 | In order to load, for example, the sha1_z990 module when the sha1 algorithm is | ||
82 | requested (see 3.2.) add 'alias sha1 sha1_z990' to /etc/modprobe.conf. | ||
83 | |||