Hello,
My understanding is that this patch isn't upstream yet and it's not too
late for bikeshedding. Please ignore if this is not the case.
Ram Pai <linux...@us.ibm.com> writes:
> @@ -326,48 +330,7 @@ static inline bool pkey_allows_readwrite(int pkey)
>
> int __execute_only_pkey(struct mm_struct *mm)
> {
> - bool need_to_set_mm_pkey = false;
> - int execute_only_pkey = mm->context.execute_only_pkey;
> - int ret;
> -
> - /* Do we need to assign a pkey for mm's execute-only maps? */
> - if (execute_only_pkey == -1) {
> - /* Go allocate one to use, which might fail */
> - execute_only_pkey = mm_pkey_alloc(mm);
> - if (execute_only_pkey < 0)
> - return -1;
> - need_to_set_mm_pkey = true;
> - }
> -
> - /*
> - * We do not want to go through the relatively costly dance to set AMR
> - * if we do not need to. Check it first and assume that if the
> - * execute-only pkey is readwrite-disabled than we do not have to set it
> - * ourselves.
> - */
> - if (!need_to_set_mm_pkey && !pkey_allows_readwrite(execute_only_pkey))
> - return execute_only_pkey;
> -
> - /*
> - * Set up AMR so that it denies access for everything other than
> - * execution.
> - */
> - ret = __arch_set_user_pkey_access(current, execute_only_pkey,
> - PKEY_DISABLE_ACCESS |
> - PKEY_DISABLE_WRITE);
> - /*
> - * If the AMR-set operation failed somehow, just return 0 and
> - * effectively disable execute-only support.
> - */
> - if (ret) {
> - mm_pkey_free(mm, execute_only_pkey);
> - return -1;
> - }
> -
> - /* We got one, store it and use it from here on out */
> - if (need_to_set_mm_pkey)
> - mm->context.execute_only_pkey = execute_only_pkey;
> - return execute_only_pkey;
> + return mm->context.execute_only_pkey;
> }
There's no reason to have a separate __execute_only_pkey() function
anymore. Its single line can go directly in execute_only_pkey(), defined
in <asm/pkeys.h>.
--
Thiago Jung Bauermann
IBM Linux Technology Center
