Re: [PATCH for-4.15 v2] xen: Bump the minimum version of GCC supported to 4.9 for arm32 and 5.1 on arm64

[Julien Grall <julien@xxxxxxx>]

Hi Ian,

On 15/03/2021 12:05, Ian Jackson wrote:
> Julien Grall writes ("[PATCH for-4.15 v2] xen: Bump the minimum version of GCC 
> supported to 4.9 for arm32 and 5.1 on arm64"):
> > From: Julien Grall <jgrall@xxxxxxxxxx>
> >
> > Compilers older than 4.8 have known codegen issues which can lead to
> > silent miscompilation:
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145
> >
> > Furthermore, pre-4.9 GCC have known bugs (including things like
> > internal compiler errors on Arm) which would require workaround (I
> > haven't checked if we have any in Xen).
> >
> > The minimum version of GCC to build the hypervisor on arm is now
> > raised to 4.9.
> >
> > In addition to that, on arm64, GCC version >= 4.9 and < 5.1 have been
> > shown to emit memory references beyond the stack pointer, resulting in
> > memory corruption if an interrupt is taken after the stack pointer has
> > been adjusted but before the reference has been executed.
> >
> > Therefore, the minimum for arm64 is raised to 5.1.
> >
> > Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Thanks! I have committed the patch with Bertrand and Stefano's reviewed-by.

Cheers,

--
Julien Grall