Re: [PATCH] x86/mm/kaiser: avoid 32-bit/PAE build warning

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Feb 14, 2018 at 11:12:24PM +0100, Arnd Bergmann wrote:
> On Wed, Dec 6, 2017 at 4:08 PM, Dave Hansen <dave.hansen@linux.intel.com> wrote:
> > On 12/06/2017 07:03 AM, Arnd Bergmann wrote:
> >> On Wed, Dec 6, 2017 at 3:15 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> >>
> >>> This changes the type to u64 in the architecture-independent dummy,
> >>> and to pteval_t in the x86 specific portion that is used when KAISER
> >>> is enabled, ensuring that the flags can always fit. Unfortunately,
> >>> pteval_t is not provided by most other architectures, so we are
> >>> a little bit inconsistent here.
> >>
> >> I ran into a new regression with my patch applied, after doing more randconfig
> >> builds:
> >>
> >> In file included from /git/arm-soc/include/linux/kaiser.h:5,
> >>                  from /git/arm-soc/arch/x86/events/intel/ds.c:4:
> >> arch/x86/include/asm/kaiser.h:34:10: error: unknown type name
> >> 'pteval_t'; did you mean 'dev_t'?
> >>
> >> Maybe it's better to just to the last one-line change in include/linux/kaiser.h.
> >
> > Hi Arnd,
> >
> > Are you hitting this in -next?
> >
> > The newest version of this code has a single kpti_init() function that
> > shouldn't have any of these problems.
> 
> Coming back to an old thread...
> 
> I did some randconfig testing on 4.9.80, and now I see the same problem there,
> since that version uses the KAISER patches rather than PTI:
> 
> /git/arm-soc/arch/x86/kernel/ldt.c: In function 'alloc_ldt_struct':
> /git/arm-soc/arch/x86/include/asm/pgtable_types.h:208:24: error: large
> integer implicitly truncated to unsigned type [-Werror=overflow]
>  #define __PAGE_KERNEL  (__PAGE_KERNEL_EXEC | _PAGE_NX)
>                         ^
> /git/arm-soc/arch/x86/kernel/ldt.c:81:6: note: in expansion of macro
> '__PAGE_KERNEL'
>       __PAGE_KERNEL);
>       ^~~~~~~~~~~~~
> 
> I also saw another warning:
> 
> /git/arm-soc/arch/x86/mm/kaiser.c: In function 'kaiser_init':
> /git/arm-soc/arch/x86/mm/kaiser.c:347:8: error: 'vsyscall_pgprot'
> undeclared (first use in this function); did you mean
> 'massage_pgprot'?
> 
> I can send this as proper patches for inclusion in 4.9-stable, unless
> someone has a better idea or finds a problem

proper patches would be good :)

thanks,

greg k-h