On 15/06/17 12:05, Sergej Proskurin wrote:
> The current implementation does not provide appropriate types for
> short-descriptor translation table entries. As such, this commit adds new
> types, which simplify managing the respective translation table entries.
>
> Signed-off-by: Sergej Proskurin <prosku...@sec.in.tum.de>
> ---
> Cc: Stefano Stabellini <sstabell...@kernel.org>
> Cc: Julien Grall <julien.gr...@arm.com>
> ---
> v3: Add more short-descriptor related pte typedefs that will be used by
> the following commits.
> ---
> xen/include/asm-arm/page.h | 104
> +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 104 insertions(+)
>
> diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
> index e2e4b597a5..7a4aa64144 100644
> --- a/xen/include/asm-arm/page.h
> +++ b/xen/include/asm-arm/page.h
> @@ -205,6 +205,110 @@ typedef union {
> lpae_walk_t walk;
> } lpae_t;
>
> +/*
> + * Comprises bits of the level 1 short-descriptor format representing
> + * a section.
> + */
> +typedef struct __packed {
> + unsigned int pxn:1; /* Privileged Execute Never */
(I'm not an ARM maintainer, but) can I recommend using bool bitfields
for boolean fields like this.
There's no difference when using the structure for reading data, but it
helps reduce subtle bugs such as
foo.pxn = (flags & NO_EXECUTE);
when using the structures to create a new value, or modify existing ones.
~Andrew
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
