diff options
Diffstat (limited to 'arch/arm64/kernel/idreg-override.c')
| -rw-r--r-- | arch/arm64/kernel/idreg-override.c | 26 |
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; |