Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 10 Sep 2018 10:02:09 -0700 | Subject | Re: [PATCH] arch/arm64/include/asm/jump_label.h: use asm_volatile_goto |
| |
On Mon, Sep 10, 2018 at 2:49 AM Will Deacon <will.deacon@arm.com> wrote: > > On Sun, Sep 09, 2018 at 05:47:31PM +0200, Miguel Ojeda wrote: > > All other uses of "asm goto" go through asm_volatile_goto > > (including the arm version of the same file). For consistency, > > use it here as well. > > > > Cc: Nick Desaulniers <ndesaulniers@google.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > Cc: linux-arm-kernel@lists.infradead.org > > Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> > > --- > > arch/arm64/include/asm/jump_label.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > Thanks, I'll pick this up as a fix. > > Will > > > diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h > > index 1b5e0e843c3a..7e2b3e360086 100644 > > --- a/arch/arm64/include/asm/jump_label.h > > +++ b/arch/arm64/include/asm/jump_label.h > > @@ -28,7 +28,7 @@ > > > > static __always_inline bool arch_static_branch(struct static_key *key, bool branch) > > { > > - asm goto("1: nop\n\t" > > + asm_volatile_goto("1: nop\n\t" > > ".pushsection __jump_table, \"aw\"\n\t" > > ".align 3\n\t" > > ".quad 1b, %l[l_yes], %c0\n\t" > > @@ -42,7 +42,7 @@ static __always_inline bool arch_static_branch(struct static_key *key, bool bran > > > > static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) > > { > > - asm goto("1: b %l[l_yes]\n\t" > > + asm_volatile_goto("1: b %l[l_yes]\n\t" > > ".pushsection __jump_table, \"aw\"\n\t" > > ".align 3\n\t" > > ".quad 1b, %l[l_yes], %c0\n\t" > > -- > > 2.17.1 > >
Yes, this should help avoid a known miscompile in gcc < 4.8.2 (at least for x86_64; not sure how backend specific the asm goto implementation is in gcc, but this shouldn't hurt). https://lkml.org/lkml/2018/9/7/1628
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
-- Thanks, ~Nick Desaulniers
| |