diff options
Diffstat (limited to 'Documentation/s390')
| -rw-r--r-- | Documentation/s390/crypto/crypto-API.txt | 83 | ||||
| -rw-r--r-- | Documentation/s390/zfcpdump.txt | 87 |
2 files changed, 87 insertions, 83 deletions
diff --git a/Documentation/s390/crypto/crypto-API.txt b/Documentation/s390/crypto/crypto-API.txt deleted file mode 100644 index 71ae6ca9f2c..00000000000 --- a/Documentation/s390/crypto/crypto-API.txt +++ /dev/null @@ -1,83 +0,0 @@ -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 -/etc/modprobe.conf. - -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. - diff --git a/Documentation/s390/zfcpdump.txt b/Documentation/s390/zfcpdump.txt new file mode 100644 index 00000000000..cf45d27c460 --- /dev/null +++ b/Documentation/s390/zfcpdump.txt @@ -0,0 +1,87 @@ +s390 SCSI dump tool (zfcpdump) + +System z machines (z900 or higher) provide hardware support for creating system +dumps on SCSI disks. The dump process is initiated by booting a dump tool, which +has to create a dump of the current (probably crashed) Linux image. In order to +not overwrite memory of the crashed Linux with data of the dump tool, the +hardware saves some memory plus the register sets of the boot cpu before the +dump tool is loaded. There exists an SCLP hardware interface to obtain the saved +memory afterwards. Currently 32 MB are saved. + +This zfcpdump implementation consists of a Linux dump kernel together with +a userspace dump tool, which are loaded together into the saved memory region +below 32 MB. zfcpdump is installed on a SCSI disk using zipl (as contained in +the s390-tools package) to make the device bootable. The operator of a Linux +system can then trigger a SCSI dump by booting the SCSI disk, where zfcpdump +resides on. + +The kernel part of zfcpdump is implemented as a debugfs file under "zcore/mem", +which exports memory and registers of the crashed Linux in an s390 +standalone dump format. It can be used in the same way as e.g. /dev/mem. The +dump format defines a 4K header followed by plain uncompressed memory. The +register sets are stored in the prefix pages of the respective cpus. To build a +dump enabled kernel with the zcore driver, the kernel config option +CONFIG_ZFCPDUMP has to be set. When reading from "zcore/mem", the part of +memory, which has been saved by hardware is read by the driver via the SCLP +hardware interface. The second part is just copied from the non overwritten real +memory. + +The userspace application of zfcpdump can reside e.g. in an intitramfs or an +initrd. It reads from zcore/mem and writes the system dump to a file on a +SCSI disk. + +To build a zfcpdump kernel use the following settings in your kernel +configuration: + * CONFIG_ZFCPDUMP=y + * Enable ZFCP driver + * Enable SCSI driver + * Enable ext2 and ext3 filesystems + * Disable as many features as possible to keep the kernel small. + E.g. network support is not needed at all. + +To use the zfcpdump userspace application in an initramfs you have to do the +following: + + * Copy the zfcpdump executable somewhere into your Linux tree. + E.g. to "arch/s390/boot/zfcpdump. If you do not want to include + shared libraries, compile the tool with the "-static" gcc option. + * If you want to include e2fsck, add it to your source tree, too. The zfcpdump + application attempts to start /sbin/e2fsck from the ramdisk. + * Use an initramfs config file like the following: + + dir /dev 755 0 0 + nod /dev/console 644 0 0 c 5 1 + nod /dev/null 644 0 0 c 1 3 + nod /dev/sda1 644 0 0 b 8 1 + nod /dev/sda2 644 0 0 b 8 2 + nod /dev/sda3 644 0 0 b 8 3 + nod /dev/sda4 644 0 0 b 8 4 + nod /dev/sda5 644 0 0 b 8 5 + nod /dev/sda6 644 0 0 b 8 6 + nod /dev/sda7 644 0 0 b 8 7 + nod /dev/sda8 644 0 0 b 8 8 + nod /dev/sda9 644 0 0 b 8 9 + nod /dev/sda10 644 0 0 b 8 10 + nod /dev/sda11 644 0 0 b 8 11 + nod /dev/sda12 644 0 0 b 8 12 + nod /dev/sda13 644 0 0 b 8 13 + nod /dev/sda14 644 0 0 b 8 14 + nod /dev/sda15 644 0 0 b 8 15 + file /init arch/s390/boot/zfcpdump 755 0 0 + file /sbin/e2fsck arch/s390/boot/e2fsck 755 0 0 + dir /proc 755 0 0 + dir /sys 755 0 0 + dir /mnt 755 0 0 + dir /sbin 755 0 0 + + * Issue "make image" to build the zfcpdump image with initramfs. + +In a Linux distribution the zfcpdump enabled kernel image must be copied to +/usr/share/zfcpdump/zfcpdump.image, where the s390 zipl tool is looking for the +dump kernel when preparing a SCSI dump disk. + +If you use a ramdisk copy it to "/usr/share/zfcpdump/zfcpdump.rd". + +For more information on how to use zfcpdump refer to the s390 'Using the Dump +Tools book', which is available from +http://www.ibm.com/developerworks/linux/linux390. |