Re: [PATCH 1/2] riscv: Include riscv_set_icache_flush_ctx prctl

[Conor Dooley]

On Wed, Nov 22, 2023 at 05:03:20PM -0800, Charlie Jenkins wrote:
> +
> +/**
> + * Enable userspace to emit icache flushing instructions.
> + *
> + * When in per-process context, there may be multiple threads using the same mm.
> + * Therefore, the icache can never be assumed clean when. Multiple threads in
> + * the process may modify instructions in the mm concurrently.
> + *
> + * In per-thread context, it can be assumed that all modifications to
> + * instructions in memory will be performed by this thread. When the thread is
> + * migrated the icache will be flushed.
> + *
> + * @arg arg: Sets the type of context
> + *  - PR_RISCV_CTX_SW_FENCEI: Allow fence.i in userspace. Another fence.i will
> + *			      emitted on thread/process migration.
> + * @arg per_thread: When set to 0, will use the default behavior of setting the
> + *  icache flush context per process. When set to 1, will use a per thread
> + *  context.
> + */

FYI, this is not valid kerneldoc and breaks allmodconfig builds:
 arch/riscv/mm/cacheflush.c:159: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

> +int riscv_set_icache_flush_ctx(unsigned long ctx, unsigned long per_thread)


Cheers,
Conor.

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