Re: [RFC PATCH for 5.2 08/10] rseq/selftests: aarch64 code signature: handle big-endian environment
From: Mark Rutland
Date: Wed Apr 24 2019 - 12:52:00 EST
On Wed, Apr 24, 2019 at 05:45:38PM +0100, Will Deacon 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. */
> It would be neater to implement swab32 and use that with RSEQ_SIG_CODE,
If possible, marginally neater than that would be using
le32_to_cpu(RSEQ_SIG_CODE), without any ifdeffery necessary.
It looks like that's defined in tools/include/linux/kernel.h, but I'm
not sure if that gets pulled into your include path.