Re: [PATCH] uaccess: add noop untagged_addr definition

[Andrey Konovalov]

On Tue, Jun 4, 2019 at 1:49 PM Koenig, Christian
<Christian.Koenig@xxxxxxx> wrote:
>
> Am 04.06.19 um 13:48 schrieb Andrey Konovalov:
> > On Tue, Jun 4, 2019 at 1:46 PM Koenig, Christian
> > <Christian.Koenig@xxxxxxx> wrote:
> >> Am 04.06.19 um 13:44 schrieb Andrey Konovalov:
> >>> Architectures that support memory tagging have a need to perform untagging
> >>> (stripping the tag) in various parts of the kernel. This patch adds an
> >>> untagged_addr() macro, which is defined as noop for architectures that do
> >>> not support memory tagging. The oncoming patch series will define it at
> >>> least for sparc64 and arm64.
> >>>
> >>> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> >>> Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
> >>> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> >>> ---
> >>>    include/linux/mm.h | 4 ++++
> >>>    1 file changed, 4 insertions(+)
> >>>
> >>> diff --git a/include/linux/mm.h b/include/linux/mm.h
> >>> index 0e8834ac32b7..949d43e9c0b6 100644
> >>> --- a/include/linux/mm.h
> >>> +++ b/include/linux/mm.h
> >>> @@ -99,6 +99,10 @@ extern int mmap_rnd_compat_bits __read_mostly;
> >>>    #include <asm/pgtable.h>
> >>>    #include <asm/processor.h>
> >>>
> >>> +#ifndef untagged_addr
> >>> +#define untagged_addr(addr) (addr)
> >>> +#endif
> >>> +
> >> Maybe add a comment what tagging actually is? Cause that is not really
> >> obvious from the context.
> > Hi,
> >
> > Do you mean a comment in the code or an explanation in the patch description?
>
> The code, the patch description actually sounds good to me.

Sent v2, thanks!

>
> Christian.
>
> >
> > Thanks!
> >
> >> Christian.
> >>
> >>>    #ifndef __pa_symbol
> >>>    #define __pa_symbol(x)  __pa(RELOC_HIDE((unsigned long)(x), 0))
> >>>    #endif
>