On Mon, Jan 22, 2024 at 08:41:53PM +0000, Mark Brown wrote: > The documentation for system vector length configuration does not cover all > cases where unsupported values are written, tighten it up. > > Reported-by: Edmund Grimley-Evans <edmund.grimley-evans@xxxxxxx> > Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> > --- > Documentation/arch/arm64/sme.rst | 5 ++--- > Documentation/arch/arm64/sve.rst | 5 ++--- > 2 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/Documentation/arch/arm64/sme.rst b/Documentation/arch/arm64/sme.rst > index 3133d0e91b48..ba0a5e5b2523 100644 > --- a/Documentation/arch/arm64/sme.rst > +++ b/Documentation/arch/arm64/sme.rst > @@ -379,9 +379,8 @@ The regset data starts with struct user_za_header, containing: > /proc/sys/abi/sme_default_vector_length > > Writing the text representation of an integer to this file sets the system > - default vector length to the specified value, unless the value is greater > - than the maximum vector length supported by the system in which case the > - default vector length is set to that maximum. > + default vector length to the specified value rounded to a supported value > + using the same rules as for setting vector length via prctl(). Do parallel changes need to be made in sve.rst? (There seems to be so much duplication and copy-paste between these files that I wonder whether it would make sense to merge them... but that's probably a separate discussion.) Nit: is it better to name the prctl here than just to say prctl()? That would be easier for the reader to cross-reference. > > The result can be determined by reopening the file and reading its > contents. > diff --git a/Documentation/arch/arm64/sve.rst b/Documentation/arch/arm64/sve.rst > index b45a2da19bf1..b923727ff4b9 100644 > --- a/Documentation/arch/arm64/sve.rst > +++ b/Documentation/arch/arm64/sve.rst > @@ -423,9 +423,8 @@ The regset data starts with struct user_sve_header, containing: > /proc/sys/abi/sve_default_vector_length > > Writing the text representation of an integer to this file sets the system > - default vector length to the specified value, unless the value is greater > - than the maximum vector length supported by the system in which case the > - default vector length is set to that maximum. > + default vector length to the specified value rounded to a supported value > + using the same rules as for setting vector length via prctl(). Ditto. [...] Cheers ---Dave
