Re: [RFC PATCH v1 18/28] prctl: arch-agnostic prtcl for indirect branch tracking

Deepak Gupta
2024-02-22T00:43:05Z

On Tue, Feb 06, 2024 at 04:13:39PM +0000, Mark Brown wrote:
>On Wed, Jan 24, 2024 at 10:21:43PM -0800, debug@rivosinc.com wrote:
>
>> To allow userspace to enable this feature for itself, following prtcls are
>> defined:
>> - PR_GET_INDIR_BR_LP_STATUS: Gets current configured status for indirect branch
>> tracking.
>> - PR_SET_INDIR_BR_LP_STATUS: Sets a configuration for indirect branch tracking
>> Following status options are allowed
>> - PR_INDIR_BR_LP_ENABLE: Enables indirect branch tracking on user
>> thread.
>> - PR_INDIR_BR_LP_DISABLE; Disables indirect branch tracking on user
>> thread.
>> - PR_LOCK_INDIR_BR_LP_STATUS: Locks configured status for indirect branch
>> tracking for user thread.
>
>FWIW the arm64 BTI feature is enabled per page of executable memory
>rather than in CPU state so it'd be hard for us to adopt this interface.
>I don't think that's a blocker, just noting it.

Got it, makes sense.