On Thu, 13 Mar 2025 10:41:10 +0000,
Mikołaj Lenczewski <miko.lenczewski@xxxxxxx> wrote:
>
> diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c
> index c6b185b885f7..9728faa10390 100644
> --- a/arch/arm64/kernel/pi/idreg-override.c
> +++ b/arch/arm64/kernel/pi/idreg-override.c
> @@ -209,6 +209,7 @@ static const struct ftr_set_desc sw_features __prel64_initconst = {
> FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL),
> FIELD("hvhe", ARM64_SW_FEATURE_OVERRIDE_HVHE, hvhe_filter),
> FIELD("rodataoff", ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF, NULL),
> + FIELD("nobbml2", ARM64_SW_FEATURE_OVERRIDE_NOBBML2, NULL),
> {}
> },
> };
> @@ -246,6 +247,7 @@ static const struct {
> { "rodata=off", "arm64_sw.rodataoff=1" },
> { "arm64.nolva", "id_aa64mmfr2.varange=0" },
> { "arm64.no32bit_el0", "id_aa64pfr0.el0=1" },
> + { "arm64.nobbml2", "arm64_sw.nobbml2=1" },
Why is that a SW feature? This looks very much like a HW feature to
me, and you should instead mask out ID_AA64MMFR2_EL1.BBM, and be done
with it. Something like:
diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c
index c6b185b885f70..803a0c99f7b46 100644
--- a/arch/arm64/kernel/pi/idreg-override.c
+++ b/arch/arm64/kernel/pi/idreg-override.c
@@ -102,6 +102,7 @@ static const struct ftr_set_desc mmfr2 __prel64_initconst = {
.override = &id_aa64mmfr2_override,
.fields = {
FIELD("varange", ID_AA64MMFR2_EL1_VARange_SHIFT, mmfr2_varange_filter),
+ FIELD("bbm", ID_AA64MMFR2_EL1_BBM_SHIFT, NULL),
{}
},
};
@@ -246,6 +247,7 @@ static const struct {
{ "rodata=off", "arm64_sw.rodataoff=1" },
{ "arm64.nolva", "id_aa64mmfr2.varange=0" },
{ "arm64.no32bit_el0", "id_aa64pfr0.el0=1" },
+ { "arm64.nobbml2", "id_aa64mmfr2.bbm=0" },
};
static int __init parse_hexdigit(const char *p, u64 *v)
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
