lkml.org 
[lkml]   [2019]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v3] arm64: sysreg: make mrs_s and msr_s macros work with Clang and LTO
On Wed, 24 Apr 2019 at 00:55, Kees Cook <keescook@chromium.org> wrote:
>
> On Mon, Apr 15, 2019 at 7:38 AM Kees Cook <keescook@chromium.org> wrote:
> > +#define __msr_s(r, v) \
> > + DEFINE_MSR_S \
> > +" msr_s " __stringify(r) ", %x0\n" \
> > + UNDEFINE_MSR_S : : "rZ" (v)
>
> BTW ... is "%x0" a typo here? Shouldn't this just be "%0"?
>

No, iirc, that is required to force clang to choose a x# encoding
(which is the only one supported by msr/mrs instructions). Otherwise,
it will infer from the operand size which encoding to use, and attempt
to use w# for 32-bit system registers.

\
 
 \ /
  Last update: 2019-04-24 00:58    [W:0.123 / U:2.620 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site