On Fri, Aug 11, 2017 at 03:39:14PM +1000, Michael Ellerman wrote:
> Thiago Jung Bauermann <bauer...@linux.vnet.ibm.com> writes:
>
> > Ram Pai <linux...@us.ibm.com> writes:
> >> static inline void pkey_initialize(void)
> >> {
> >> + int os_reserved, i;
> >> +
> >> /* disable the pkey system till everything
> >> * is in place. A patch further down the
> >> * line will enable it.
> >> */
> >> pkey_inited = false;
> >> +
> >> + /* Lets assume 32 keys */
> >> + pkeys_total = 32;
> >> +
> >> +#ifdef CONFIG_PPC_4K_PAGES
> >> + /*
> >> + * the OS can manage only 8 pkeys
> >> + * due to its inability to represent
> >> + * them in the linux 4K-PTE.
> >> + */
> >> + os_reserved = pkeys_total-8;
> >> +#else
> >> + os_reserved = 0;
> >> +#endif
> >> + /*
> >> + * Bits are in LE format.
> >> + * NOTE: 1, 0 are reserved.
> >> + * key 0 is the default key, which allows read/write/execute.
> >> + * key 1 is recommended not to be used.
> >> + * PowerISA(3.0) page 1015, programming note.
> >> + */
> >> + initial_allocation_mask = ~0x0;
> >> + for (i = 2; i < (pkeys_total - os_reserved); i++)
> >> + initial_allocation_mask &= ~(0x1<<i);
> >> }
> >> #endif /*_ASM_PPC64_PKEYS_H */
> >
> > In v6, key 31 was also reserved, but it's not in this version. Is this
> > intentional?
>
> That whole thing could be replaced with two constants.
>
> Except it can't, because we can't just hard code the number of keys. It
> needs to come either from the device tree or be based on the CPU we're
> running on.
>
> > Isn't it better for this function to be in pkeys.c? Ideally, functions
> > should be in .c files not in headers unless they're very small or
> > performance sensitive IMHO.
>
> Yes. No reason for that to be in a header AFAICS.
Yes can be moved into the pkeys.c file. It was a simple function
to begin with....but not so any more.
RP
