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d7649a4a60
When a task's SVE vector length (NSVL) is changed, and the task happens
to have SVCR.{SM,ZA}=={0,0}, vec_set_vector_length() opportunistically
frees the task's sme_state and clears TIF_SME.
The opportunistic freeing was added with no rationale in commit:
d4d5be94a8 ("arm64/fpsimd: Ensure SME storage is allocated after SVE VL changes")
That commit fixed an unrelated problem where the task's sve_state was
freed while it could be used to store streaming mode register state,
where the fix was to re-allocate the task's sve_state.
There is no need to free and/or reallocate the task's sme_state when the
SVE vector length changes, and there is no need to clear TIF_SME. Given
the SME vector length (SVL) doesn't change, the task's sme_state remains
correctly sized.
Remove the unnecessary opportunistic freeing of the task's sme_state
when the task's SVE vector length is changed. The task's sme_state is
still freed when the SME vector length is changed.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409164010.3480271-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.