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Diffstat (limited to 'arch/arm64/kernel/idreg-override.c')
-rw-r--r--arch/arm64/kernel/idreg-override.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 83f1c4b92095..e628c8ce1ffe 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -25,14 +25,26 @@ struct ftr_set_desc {
struct {
char name[FTR_DESC_FIELD_LEN];
u8 shift;
+ bool (*filter)(u64 val);
} fields[];
};
+static bool __init mmfr1_vh_filter(u64 val)
+{
+ /*
+ * If we ever reach this point while running VHE, we're
+ * guaranteed to be on one of these funky, VHE-stuck CPUs. If
+ * the user was trying to force nVHE on us, proceed with
+ * attitude adjustment.
+ */
+ return !(is_kernel_in_hyp_mode() && val == 0);
+}
+
static const struct ftr_set_desc mmfr1 __initconst = {
.name = "id_aa64mmfr1",
.override = &id_aa64mmfr1_override,
.fields = {
- { "vh", ID_AA64MMFR1_VHE_SHIFT },
+ { "vh", ID_AA64MMFR1_VHE_SHIFT, mmfr1_vh_filter },
{}
},
};
@@ -124,6 +136,18 @@ static void __init match_options(const char *cmdline)
if (find_field(cmdline, regs[i], f, &v))
continue;
+ /*
+ * If an override gets filtered out, advertise
+ * it by setting the value to 0xf, but
+ * clearing the mask... Yes, this is fragile.
+ */
+ if (regs[i]->fields[f].filter &&
+ !regs[i]->fields[f].filter(v)) {
+ regs[i]->override->val |= mask;
+ regs[i]->override->mask &= ~mask;
+ continue;
+ }
+
regs[i]->override->val &= ~mask;
regs[i]->override->val |= (v << shift) & mask;
regs[i]->override->mask |= mask;