Messages in this thread | | | Date | Fri, 17 Jul 2020 11:17:18 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH RFC V2 12/17] memremap: Add zone device access protection |
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On Fri, Jul 17, 2020 at 12:20:51AM -0700, ira.weiny@intel.com 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(); }
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