diff options
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 17 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 6 | ||||
| -rw-r--r-- | arch/arm64/kernel/idreg-override.c | 13 |
3 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 61177bac49fa..338840c00e8e 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -63,6 +63,23 @@ struct arm64_ftr_bits { s64 safe_val; /* safe value for FTR_EXACT features */ }; +/* + * Describe the early feature override to the core override code: + * + * @val Values that are to be merged into the final + * sanitised value of the register. Only the bitfields + * set to 1 in @mask are valid + * @mask Mask of the features that are overridden by @val + * + * A @mask field set to full-1 indicates that the corresponding field + * in @val is a valid override. + * + * A @mask field set to full-0 with the corresponding @val field set + * to full-0 denotes that this field has no override + * + * A @mask field set to full-0 with the corresponding @val field set + * to full-1 denotes thath this field has an invalid override. + */ struct arm64_ftr_override { u64 val; u64 mask; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 066030717a4c..6de15deaa912 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -809,6 +809,12 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) reg->name, ftrp->shift + ftrp->width - 1, ftrp->shift, str, tmp); + } else if ((ftr_mask & reg->override->val) == ftr_mask) { + reg->override->val &= ~ftr_mask; + pr_warn("%s[%d:%d]: impossible override, ignored\n", + reg->name, + ftrp->shift + ftrp->width - 1, + ftrp->shift); } val = arm64_ftr_set_value(ftrp, val, ftr_new); diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 83f1c4b92095..be92fcd319a1 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -25,6 +25,7 @@ struct ftr_set_desc { struct { char name[FTR_DESC_FIELD_LEN]; u8 shift; + bool (*filter)(u64 val); } fields[]; }; @@ -124,6 +125,18 @@ 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; |