Re: [PATCH v3 21/36] arm64/mm: Implement map_shadow_stack()

[Szabolcs Nagy]

The 07/31/2023 14:43, Mark Brown wrote:
> +SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsigned int, flags)
> +{
> +	unsigned long alloc_size;
> +	unsigned long __user *cap_ptr;
> +	unsigned long cap_val;
> +	int ret;
> +
> +	if (!system_supports_gcs())
> +		return -EOPNOTSUPP;
> +
> +	if (flags)
> +		return -EINVAL;
> +
> +	if (addr % 16)
> +		return -EINVAL;

mmap addr must be page aligned (and there is no align req on size).

i'd expect similar api here.

> +
> +	if (size == 16 || size % 16)
> +		return -EINVAL;

why %16 and not %8 ?