Re: [PATCH v4 1/3] xen/arm: add support for run_in_exception_handler()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.12.2020 08:56, Juergen Gross wrote:
> Add support to run a function in an exception handler for Arm. Do it
> the same way as on x86 via a bug_frame.
> 
> Unfortunately inline assembly on Arm seems to be less capable than on
> x86, leading to functions called via run_in_exception_handler() having
> to be globally visible.

Could you extend on this? I don't understand what the relevant
difference is, from just looking at the changes.

> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
> V4:
> - new patch
> 
> I have verified the created bugframe is correct by inspecting the
> created binary.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
>  xen/arch/arm/traps.c       | 10 +++++++++-
>  xen/drivers/char/ns16550.c |  3 ++-
>  xen/include/asm-arm/bug.h  | 32 +++++++++++++++++++++-----------
>  3 files changed, 32 insertions(+), 13 deletions(-)

Aiui you also need to modify xen.lds.S to cover the new (or really
the last renamed) section.

Jan