Messages in this thread | | | From | Rob Herring <> | Date | Mon, 15 Nov 2021 10:57:34 -0600 | Subject | Re: [PATCH v12 0/5] Another version of arm64 userspace counter access support. |
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On Wed, Oct 27, 2021 at 3:16 PM Rob Herring <robh@kernel.org> wrote: > > The arm64 support departs from the x86 implementation by requiring the user > to explicitly request user access (via attr.config1) and only enables access > for task bound events. Since usage is explicitly requested, access is > enabled at perf_event_open() rather than on mmap() as that greatly > simplifies the implementation. Rather than trying to lock down the access > as the x86 implementation has been doing, we can start with only a limited > use case enabled and later expand it if needed. > > I've run this version thru Vince's perf tests[14] with arm64 support added. > I wish I'd found these tests sooner... > > This originally resurrected Raphael's series[1] to enable userspace counter > access on arm64. My previous versions are here > [2][3][4][5][6][7][8][9][10][11][12]. > A git branch is here[13]. > > Changes in v12: > - Zero PMSELR_EL0 when userspace access is enabled > - Return -EOPNOTSUPP for if h/w doesn't support 64-bit counters
Will, the series rebases cleanly on v5.16-rc1. Please let me know if you want me to resend.
Peter, Will is waiting on an ack on the core/x86 bits from you.
Rob
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