lkml.org 
[lkml]   [2019]   [Apr]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH for 5.2 08/10] rseq/selftests: aarch64 code signature: handle big-endian environment
On Wed, Apr 24, 2019 at 05:40:33PM +0100, Mark Rutland wrote:
> On Wed, Apr 24, 2019 at 11:25:00AM -0400, Mathieu Desnoyers wrote:
> > +/*
> > + * aarch64 -mbig-endian generates mixed endianness code vs data:
> > + * little-endian code and big-endian data. Ensure the RSEQ_SIG signature
> > + * matches code endianness.
> > + */
> > +#define RSEQ_SIG_CODE 0xd428bc00 /* BRK #0x45E0. */
> > +
> > +#ifdef __AARCH64EB__
> > +#define RSEQ_SIG_DATA 0x00bc28d4 /* BRK #0x45E0. */
> > +#else
> > +#define RSEQ_SIG_DATA RSEQ_SIG_CODE
> > +#endif
> > +
> > +#define RSEQ_SIG RSEQ_SIG_DATA
> >
> > #define rseq_smp_mb() __asm__ __volatile__ ("dmb ish" ::: "memory")
> > #define rseq_smp_rmb() __asm__ __volatile__ ("dmb ishld" ::: "memory")
> > @@ -121,7 +134,7 @@ do { \
> >
> > #define RSEQ_ASM_DEFINE_ABORT(label, abort_label) \
> > " b 222f\n" \
> > - " .inst " __rseq_str(RSEQ_SIG) "\n" \
> > + " .inst " __rseq_str(RSEQ_SIG_CODE) "\n" \
>
> I don't think this is right; the .inst directive _should_ emit the value
> in the instruction stream endianness (i.e. LE, regardless of the data
> endianness).

Now I see the RSEQ_CODE value isn't endian-swapped as teh RSEQ_DATA
value is, so the code above is fine.

Sory for the noise.

Thanks,
Mark.

\
 
 \ /
  Last update: 2019-04-24 18:46    [W:0.078 / U:6.372 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site