> Von: David Laight [David.Laight@xxxxxxxxxx] > Gesendet: Mittwoch, 25. Februar 2015 13:01 > An: Markus Stockhausen; linux-crypto@xxxxxxxxxxxxxxx > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx > Betreff: RE: [PATCH v1 1/3] SHA1 for PPC/SPE - assembler > > From: Markus Stockhausen > > [PATCH v1 1/3] SHA1 for PPC/SPE - assembler > > > > This is the assembler code for SHA1 implementation with > > the SIMD SPE instruction set. With the enhanced instruction > > set we can operate on 2 32 bit words in parallel. That helps > > reducing the time to calculate W16-W79. For increasing > > performance even more the assembler function can compute > > hashes for more than one 64 byte input block. > > > > The state of the used SPE registers is preserved via the > > stack so we can run from interrupt context > > Does the ppc use the same kind of delayed state save for the SPE > resisters that x86 uses (at least on the BSDs) for its FP (etc) regs. > > That would mean that the registers might contain values for > a different process, and that the cpu could receive an IPI > requesting they be written to the processes normal save area > so that they can be reloaded onto a different cpu. Indeed SPE registers are lazy switched. enable_kernel_spe() will take care of that. Additionally I had some discussions about interrupt context and its limitations. So 1) I implemented register saving in all patches (see AES & SHA256). This is because I know which registers I will overwrite. One should remember that SPE registers are shared with normal registers. So no big impact to save 32 bit or 64 bit of the non-volatile PPC registers. 2) And used disabling of preemption. But in contrast to other crypto algorithm implementations only for reasonable time intervals Markus
**************************************************************************** Diese E-Mail enthält vertrauliche und/oder rechtlich geschützte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und vernichten Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail ist nicht gestattet. �ber das Internet versandte E-Mails können unter fremden Namen erstellt oder manipuliert werden. Deshalb ist diese als E-Mail verschickte Nachricht keine rechtsverbindliche Willenserklärung. Collogia Unternehmensberatung AG Ubierring 11 D-50678 Köln Vorstand: Kadir Akin Dr. Michael Höhnerbach Vorsitzender des Aufsichtsrates: Hans Kristian Langva Registergericht: Amtsgericht Köln Registernummer: HRB 52 497 This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. e-mails sent over the internet may have been written under a wrong name or been manipulated. That is why this message sent as an e-mail is not a legally binding declaration of intention. Collogia Unternehmensberatung AG Ubierring 11 D-50678 Köln executive board: Kadir Akin Dr. Michael Höhnerbach President of the supervisory board: Hans Kristian Langva Registry office: district court Cologne Register number: HRB 52 497 ****************************************************************************