Re: [PATCH 06/13] fork: Add generic vmalloced stack support

[Kees Cook]

On Wed, Jun 15, 2016 at 5:28 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> If CONFIG_VMAP_STACK is selected, kernel stacks are allocated with
> vmalloc_node.
>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
>  arch/Kconfig  | 12 ++++++++++++
>  kernel/fork.c | 45 +++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 49 insertions(+), 8 deletions(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index d794384a0404..1acd262036b0 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -658,4 +658,16 @@ config ARCH_NO_COHERENT_DMA_MMAP
>  config CPU_NO_EFFICIENT_FFS
>         def_bool n
>
> +config HAVE_ARCH_VMAP_STACK
> +       def_bool n

In the style of HAVE_ARCH_SECCOMP_FILTER, can you detail all the
things an architecture needs to do to correctly support a vmap stack?
This will help with arch porting.

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security