Michael Ellerman <m...@ellerman.id.au> writes:
> "Aneesh Kumar K.V" <aneesh.ku...@linux.ibm.com> writes:
>
.....
>> @@ -232,8 +246,9 @@ void __init setup_kuap(bool disabled)
>> cur_cpu_spec->mmu_features |= MMU_FTR_KUAP;
>> }
>>
>> - /* Make sure userspace can't change the AMR */
>> - mtspr(SPRN_UAMOR, 0);
>
> Why not just leave it there. It's extra insurance and it's good
> documentation.
We can't se the value to 0, because with hash kuap it is derived
from what other keys are used for. Are you suggesting to keep it as
if (radix_enabled())
mtspr(SPRN_UAMOR, 0);
That would confuse w.r.t what happens with hash.
I can add a comment there explaining details?
>
>> + /*
>> + * Set the default kernel AMR values on all cpus.
>> + */
>> mtspr(SPRN_AMR, AMR_KUAP_BLOCKED);
>> isync();
>> }
>> @@ -278,11 +293,6 @@ static inline u64 read_uamor(void)
>> return mfspr(SPRN_UAMOR);
>> }
>>
>> -static inline void write_uamor(u64 value)
>> -{
>> - mtspr(SPRN_UAMOR, value);
>> -}
>> -
>> static bool is_pkey_enabled(int pkey)
>> {
>> u64 uamor = read_uamor();
>> @@ -353,7 +363,6 @@ void thread_pkey_regs_save(struct thread_struct *thread)
>> */
>> thread->amr = read_amr();
>> thread->iamr = read_iamr();
>> - thread->uamor = read_uamor();
>> }
>>
>> void thread_pkey_regs_restore(struct thread_struct *new_thread,
>> @@ -366,8 +375,6 @@ void thread_pkey_regs_restore(struct thread_struct
>> *new_thread,
>> write_amr(new_thread->amr);
>> if (old_thread->iamr != new_thread->iamr)
>> write_iamr(new_thread->iamr);
>> - if (old_thread->uamor != new_thread->uamor)
>> - write_uamor(new_thread->uamor);
>> }
>>
>> void thread_pkey_regs_init(struct thread_struct *thread)
>> @@ -377,11 +384,9 @@ void thread_pkey_regs_init(struct thread_struct *thread)
>>
>> thread->amr = default_amr;
>> thread->iamr = default_iamr;
>> - thread->uamor = default_uamor;
>>
>> write_amr(default_amr);
>> write_iamr(default_iamr);
>> - write_uamor(default_uamor);
>> }
>>
>> int execute_only_pkey(struct mm_struct *mm)
>
> cheers
-aneesh
