公开(公告)号：US20220292183A1

公开(公告)日：2022-09-15

申请号：US17826622

申请日：2022-05-27

Applicant: SiFive, Inc.

Inventor： Alex Solomatnikov ,  Krste Asanovic ,  Yann Loisel ,  Cyril Bresch

IPC: G06F21/52

Abstract: Systems and methods are disclosed for secure control flow prediction. Some implementations may be used to eliminate or mitigate the Spectre-class of attacks in a processor. For example, an integrated circuit (e.g., a processor) for executing instructions may include a control flow predictor with entries that include branch target addresses associated with instructions. The branch target addresses may be predictions. A context tag associated with an entry may be compared to a context identifier associated with a currently executing process. Responsive to a mismatch between the context tag and the context identifier, the control flow predictor may provide an alternate value in place of a branch target address.

公开(公告)号：US11347507B2

公开(公告)日：2022-05-31

申请号：US16241455

申请日：2019-01-07

Applicant: SiFive, Inc.

Inventor： Alex Solomatnikov ,  Krste Asanovic

IPC: G06F9/30 ,  G06F12/0815 ,  G06F12/1027 ,  G06F12/02 ,  G06F9/50 ,  G06F9/355

Abstract: Systems and methods are disclosed for secure control flow prediction. Some implementations may be used to eliminate or mitigate the Spectre-class of attacks in a processor. For example, an integrated circuit (e.g., a processor) for executing instructions includes a control flow predictor with entries that include respective indications of whether the entry has been activated for use in a current process, wherein the integrated circuit is configured to access the indication in one of the entries that is associated with a control flow instruction that is scheduled for execution; determine, based on the indication, whether the entry of the control flow predictor associated with the control flow instruction is activated for use in a current process; and responsive to a determination that the entry is not activated for use in the current process, apply a constraint on speculative execution based on control flow prediction for the control flow instruction.

公开(公告)号：US20190286443A1

公开(公告)日：2019-09-19

申请号：US16241455

申请日：2019-01-07

Applicant: SiFive, Inc.

Inventor： Alex Solomatnikov ,  Krste Asanovic

IPC: G06F9/30 ,  G06F12/0815 ,  G06F12/1027 ,  G06F9/355 ,  G06F9/50 ,  G06F12/02

Abstract: Systems and methods are disclosed for secure control flow prediction. Some implementations may be used to eliminate or mitigate the Spectre-class of attacks in a processor. For example, an integrated circuit (e.g., a processor) for executing instructions includes a control flow predictor with entries that include respective indications of whether the entry has been activated for use in a current process, wherein the integrated circuit is configured to access the indication in one of the entries that is associated with a control flow instruction that is scheduled for execution; determine, based on the indication, whether the entry of the control flow predictor associated with the control flow instruction is activated for use in a current process; and responsive to a determination that the entry is not activated for use in the current process, apply a constraint on speculative execution based on control flow prediction for the control flow instruction.