[PATCH v6 0/7] lib: sbi: sse: rework event availability

[Anup Patel]

On Fri, Jan 10, 2025 at 6:55 PM Clément Léger <cleger at rivosinc.com> wrote:
>
> While reworking the Linux SSE support, it appears that the PMU event
> should not be available if the SSCOFPMF extension is not available since
> there would be no IRQ. A request to modify the specification has been
> send in order to add the possibility to return SBI_ENOTSUPP (see [1]).
> This small series modifies the SSE core to allow adding new events at
> boot time using sbi_sse_add_event(). Aditionally, it now returns
> SBI_ERR_NOT_SUPPORTED if the requested event can not be handled by any
> driver.
>
> Link: https://lists.riscv.org/g/tech-prs/message/1123 [1]
>
> ---
> Changes in V6
>  - Add double trap event if dbltrp extension is available
>
> Changes in V5
>  - Remove a blank line before sse_event_info
>  - Move PMU call to sbi_sse_add_event() in cold_boot path.
>  - Move simply-linked list implementation to a separate header.
>
> Changes in V4:
>  - Used unsigned long for pmu_rq_bit_mask()
>  - Moved pmu irq check in default case rather than hot path
>  - Changed the supported event array to be a list, allowing for drivers
>    to register additional handled events.
>  - Check for supported events at init time.
>  - Remove the need for is_supported callback
>
> Changes in V3:
>  - Rework is_supported_cb() to allow per-hart local event availability
>  - Remove now useless cached_version of is_supported.
>  - Fix eret check + potential empty eret in case event_is_supported()
>    returns SBI_SUCCESS.
>  - Split commit to set all non software events as non injectable at the
>    end of the series.
>  - Fix usage of sbi_pmu_irq_bit() in sbi_pmu.c
>
> Changes in v2:
>  - Add an sse_event_info struct that stores 'cb_ops' as well as 'supported'
>  - Move SSE initialization after all other "drivers" init.
>  - Split changes in multiple commits
>  - Added an is_supported callback to check for event availability
>
> Clément Léger (7):
>   lib: sbi: pmu: fix usage of sbi_pmu_irq_bit()
>   lib: sbi: move sbi_double_trap_handler() to a dedicated header
>   lib: sbi: sse: return an error value from sse_event_get()
>   include: lib: add a simple simply linked list implementation
>   lib: sbi: sse: allow adding new events
>   lib: sbi: sse: return SBI_ENOTSUPP for unsupported events
>   lib: sbi: pmu: add the PMU SSE event only if overflow IRQ is supported

Applied this series to the riscv/opensbi repo.

Thanks,
Anup

>
>  include/sbi/sbi_double_trap.h                 |  20 ++
>  include/sbi/sbi_pmu.h                         |   3 +
>  include/sbi/sbi_slist.h                       |  33 +++
>  include/sbi/sbi_sse.h                         |   8 +-
>  include/sbi/sbi_trap_ldst.h                   |   2 -
>  lib/sbi/sbi_double_trap.c                     |   7 +
>  lib/sbi/sbi_hart.c                            |   2 +-
>  lib/sbi/sbi_init.c                            |  27 ++-
>  lib/sbi/sbi_pmu.c                             |  47 ++--
>  lib/sbi/sbi_sse.c                             | 209 ++++++++++++------
>  lib/sbi/sbi_trap.c                            |  16 +-
>  .../generic/include/thead/c9xx_encoding.h     |   1 -
>  platform/generic/thead/thead_c9xx_pmu.c       |   2 +-
>  13 files changed, 264 insertions(+), 113 deletions(-)
>  create mode 100644 include/sbi/sbi_double_trap.h
>  create mode 100644 include/sbi/sbi_slist.h
>
> --
> 2.47.1
>
>
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