Re: [PATCH v2 2/2] xen/riscv: add explicit check that .got{.plt} is empty

[Alistair Francis <alistair23@xxxxxxxxx>]

On Thu, Mar 16, 2023 at 11:22 PM Oleksii Kurochko
<oleksii.kurochko@xxxxxxxxx> wrote:
>
> The GOT sections usage should be avoided in the hypervisor
> so to catch such use cases earlier when GOT things are
> produced the patch introduces .got and .got.plt sections
> and adds asserts that they're empty.
>
> The sections won't be created until they remain
> empty otherwise the asserts would cause early failure.
>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

Acked-by: Alistair Francis <alistair.francis@xxxxxxx>

Alistair

> ---
> Changes in V2:
>  * the patch was introduced in patch series v2.
> ---
>  xen/arch/riscv/xen.lds.S | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
> index ca57cce75c..f299ea8422 100644
> --- a/xen/arch/riscv/xen.lds.S
> +++ b/xen/arch/riscv/xen.lds.S
> @@ -1,3 +1,4 @@
> +#include <xen/lib.h>
>  #include <xen/xen.lds.h>
>
>  #undef ENTRY
> @@ -123,6 +124,15 @@ SECTIONS
>          *(SORT(.init_array.*))
>          __ctors_end = .;
>      } :text
> +
> +    .got : {
> +        *(.got)
> +    } : text
> +
> +    .got.plt : {
> +        *(.got.plt)
> +    } : text
> +
>      . = ALIGN(POINTER_ALIGN);
>      __init_end = .;
>
> @@ -156,3 +166,6 @@ SECTIONS
>
>      ELF_DETAILS_SECTIONS
>  }
> +
> +ASSERT(!SIZEOF(.got),      ".got non-empty")
> +ASSERT(!SIZEOF(.got.plt),  ".got.plt non-empty")
> --
> 2.39.2
>
>