On Thu, 29 May 2025 12:30:26 +0100, James Clark <james.clark@xxxxxxxxxx> wrote: > > SPE data source filtering (optional from Armv8.8) requires that traps to > the filter register PMSDSFR be disabled. Document the requirements and > disable the traps if the feature is present. > > Signed-off-by: James Clark <james.clark@xxxxxxxxxx> > --- > Documentation/arch/arm64/booting.rst | 11 +++++++++++ > arch/arm64/include/asm/el2_setup.h | 14 ++++++++++++++ > 2 files changed, 25 insertions(+) > > diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst > index dee7b6de864f..abd75085a239 100644 > --- a/Documentation/arch/arm64/booting.rst > +++ b/Documentation/arch/arm64/booting.rst > @@ -404,6 +404,17 @@ Before jumping into the kernel, the following conditions must be met: > - HDFGWTR2_EL2.nPMICFILTR_EL0 (bit 3) must be initialised to 0b1. > - HDFGWTR2_EL2.nPMUACR_EL1 (bit 4) must be initialised to 0b1. > > + For CPUs with SPE data source filtering (FEAT_SPE_FDS): > + > + - If EL3 is present: > + > + - MDCR_EL3.EnPMS3 (bit 42) must be initialised to 0b1. > + > + - If the kernel is entered at EL1 and EL2 is present: > + > + - HDFGRTR2_EL2.nPMSDSFR_EL1 (bit 19) must be initialised to 0b1. > + - HDFGWTR2_EL2.nPMSDSFR_EL1 (bit 19) must be initialised to 0b1. > + > For CPUs with Memory Copy and Memory Set instructions (FEAT_MOPS): > > - If the kernel is entered at EL1 and EL2 is present: > diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h > index f6d72ca03133..6d0d8c25e912 100644 > --- a/arch/arm64/include/asm/el2_setup.h > +++ b/arch/arm64/include/asm/el2_setup.h > @@ -279,6 +279,20 @@ > orr x0, x0, #HDFGRTR2_EL2_nPMICFILTR_EL0 > orr x0, x0, #HDFGRTR2_EL2_nPMUACR_EL1 > .Lskip_pmuv3p9_\@: > + mrs x1, id_aa64dfr0_el1 > + ubfx x1, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4 > + /* If SPE is implemented, */ > + cmp x1, #ID_AA64DFR0_EL1_PMSVer_IMP > + b.lt .Lskip_spefds_\@ > + /* we can read PMSIDR and */ > + mrs_s x1, SYS_PMSIDR_EL1 > + and x1, x1, #(1 << PMSIDR_EL1_FDS_SHIFT) Use PMSIDR_EL1_FDS directly, just like you do for the other register fields. M. -- Without deviation from the norm, progress is not possible.
