At the moment we have some elaborate, but very schematic functions to
allow checking for CPU feature enablement. Adding some more becomes
tedious and is also error-prone.
Provide two wrapper macros that reduce most of the features to a
single line:
- CREATE_FEATURE_FUNCS(name, idreg, idfield, guard)
creates two functions read_<name>_id_field() and is_<name>_supported(),
that check the 4-bit CPU ID field starting at bit <idfield> in <idreg>
for being not 0, and compares it against the build time <guard> symbol.
For the usual feature (like PAN) this looks like:
CREATE_FEATURE_FUNCS(feat_pan, id_aa64mmfr1_el1,
ID_AA64MMFR1_EL1_PAN_SHIFT, ENABLE_FEAT_PAN)
- CREATE_FEATURE_FUNCS_VER(name, read_func, idvalue, guard)
creates one function to check for a certain CPU ID field *value*, so
when "!= 0" is not sufficient. It's meant to be used in addition to
the above macro, since that generates the CPU ID field accessor
function:
CREATE_FEATURE_FUNCS(feat_amu, id_aa64pfr0_el1, ID_AA64PFR0_AMU_SHIFT,
ENABLE_FEAT_AMU)
CREATE_FEATURE_FUNCS_VER(feat_amuv1p1, read_feat_amu_id_field,
ID_AA64PFR0_AMU_V1P1, ENABLE_FEAT_AMUv1p1)
Describe the existing feature accessor functions using those new macros,
to reduce the size of the file, improve readability and decrease the
possibility of (copy&paste) bugs.
Change-Id: Ib136a875b4857058ff561c4635ace344006f29bf
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Andre Przywara
a8d5d3d540