Re: [PATCH 06/13] arc: define syscall_get_arch()

Alexey Brodkin
2018-11-09T15:27:19Z

Hi Andy,

On Fri, 2018-11-09 at 07:17 -0800, Andy Lutomirski wrote:
> On Fri, Nov 9, 2018 at 6:22 AM Alexey Brodkin
> <alexey.brodkin@synopsys.com> wrote:
> > Hi Dmitry,
> >
> > On Fri, 2018-11-09 at 06:16 +0300, Dmitry V. Levin wrote:
> > > syscall_get_arch() is required to be implemented on all architectures
> > > that use tracehook_report_syscall_entry() in order to extend
> > > the generic ptrace API with PTRACE_GET_SYSCALL_INFO request.
> > >
> > > Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> > > ---
> > > arch/arc/include/asm/syscall.h | 6 ++++++
> > > include/uapi/linux/audit.h | 1 +
> > > 2 files changed, 7 insertions(+)
> >
> > [snip]
> >
> > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> > > index 818ae690ab79..a7149ceb5b98 100644
> > > --- a/include/uapi/linux/audit.h
> > > +++ b/include/uapi/linux/audit.h
> > > @@ -375,6 +375,7 @@ enum {
> > >
> > > #define AUDIT_ARCH_AARCH64 (EM_AARCH64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
> > > #define AUDIT_ARCH_ALPHA (EM_ALPHA|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
> > > +#define AUDIT_ARCH_ARC (EM_ARC)
> >
> > Similarly here we need to have:
> > ---------------------------->8-----------------------------
> > +#define AUDIT_ARCH_ARC (EM_ARC|EM_ARCV2)
> > ---------------------------->8-----------------------------
> >
>
> Huh? How does the bitwise or of two ELF machine codes make any sense?

Oops... I didn't read examples of AUDIT_ARCH_ALPHA above :(
Indeed that was stupid.

But what would be a proper fix then?

Something like that?
---------------------------->8-----------------------------
#define AUDIT_ARCH_ARC (EM_ARC)
#define AUDIT_ARCH_ARCV2 (EM_ARCV2)

static inline int syscall_get_arch(void)
{
#ifdef __ARC700__
return AUDIT_ARCH_ARC;
#else
return AUDIT_ARCH_ARCV2;
#endif
}
---------------------------->8-----------------------------

-Alexey