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Date:   Mon, 7 Aug 2023 11:20:58 +0100
From:   Szabolcs Nagy <Szabolcs.Nagy@arm.com>
To:     Mark Brown <broonie@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
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Cc:     "H.J. Lu" <hjl.tools@gmail.com>,
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Subject: Re: [PATCH v3 21/36] arm64/mm: Implement map_shadow_stack()
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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 ?