Re: [PATCH] Added ability to vmalloc executable memory

Mark Rutland
2022-12-09T13:17:17Z

On Fri, Dec 09, 2022 at 02:10:52PM +0100, Xander Moerkerken wrote:
> From: Xander Moerkerken <xander.moerkerken@gmail.com>
>
> Since release 5.8-rc1 the pgprot got removed from __vmalloc
> because the only usage was PAGE_KERNEL as argument.
> However, this removes the ability to input other arguments
> such as 'PAGE_KERNEL_EXEC', which can be used to allocate
> memory in which you can execute. For this reason a new
> function is introduced called '__vmalloc_exec'.
>
> Signed-off-by: Xander Moerkerken <xander.moerkerken@omron.com>

What is this going to be used for? There's no user from this patch alone, as a
module or otherwise.

Mark.

> ---
> include/linux/vmalloc.h | 1 +
> mm/vmalloc.c | 8 ++++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 096d48aa3437..10c46513b6b2 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -147,6 +147,7 @@ extern void *vzalloc_node(unsigned long size, int node) __alloc_size(1);
> extern void *vmalloc_32(unsigned long size) __alloc_size(1);
> extern void *vmalloc_32_user(unsigned long size) __alloc_size(1);
> extern void *__vmalloc(unsigned long size, gfp_t gfp_mask) __alloc_size(1);
> +extern void *__vmalloc_exec(unsigned long size, gfp_t gfp_mask) __alloc_size(1);
> extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
> unsigned long start, unsigned long end, gfp_t gfp_mask,
> pgprot_t prot, unsigned long vm_flags, int node,
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index ccaa461998f3..8fd01ed7082b 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3294,6 +3294,14 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask)
> }
> EXPORT_SYMBOL(__vmalloc);
>
> +
> +void *__vmalloc_exec(unsigned long size, gfp_t gfp_mask)
> +{
> + return __vmalloc_node_prot(size, 1, gfp_mask, PAGE_KERNEL_EXEC,
> + NUMA_NO_NODE, __builtin_return_address(0));
> +}
> +EXPORT_SYMBOL(__vmalloc_exec);
> +
> /**
> * vmalloc - allocate virtually contiguous memory
> * @size: allocation size
> --
> 2.37.2
>