Re: [PATCH RFC V2 12/17] memremap: Add zone device access protection

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Jul 17, 2020 at 12:20:51AM -0700, ira.weiny@xxxxxxxxx wrote:
> +void dev_access_disable(void)
> +{
> +	unsigned long flags;
> +
> +	if (!static_branch_unlikely(&dev_protection_static_key))
> +		return;
> +
> +	local_irq_save(flags);
> +	current->dev_page_access_ref--;
> +	if (current->dev_page_access_ref == 0)

	if (!--current->dev_page_access_ref)

> +		pks_update_protection(dev_page_pkey, PKEY_DISABLE_ACCESS);
> +	local_irq_restore(flags);
> +}
> +EXPORT_SYMBOL_GPL(dev_access_disable);
> +
> +void dev_access_enable(void)
> +{
> +	unsigned long flags;
> +
> +	if (!static_branch_unlikely(&dev_protection_static_key))
> +		return;
> +
> +	local_irq_save(flags);
> +	/* 0 clears the PKEY_DISABLE_ACCESS bit, allowing access */
> +	if (current->dev_page_access_ref == 0)
> +		pks_update_protection(dev_page_pkey, 0);
> +	current->dev_page_access_ref++;

	if (!current->dev_page_access_ref++)

> +	local_irq_restore(flags);
> +}
> +EXPORT_SYMBOL_GPL(dev_access_enable);


Also, you probably want something like:

static __always_inline devm_access_disable(void)
{
	if (static_branch_unlikely(&dev_protection_static_key))
		__devm_access_disable();
}

static __always_inline devm_access_enable(void)
{
	if (static_branch_unlikely(&dev_protection_static_key))
		__devm_access_enable();
}



[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux