Hi,
On Thu, Feb 04, 2016 at 03:00:11PM +0530, ankitprasad.r.sharma@xxxxxxxxx wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
>
> The BIOS RapidStartTechnology may corrupt the stolen memory across S3
> suspend due to unalarmed hibernation, in which case we will not be able
> to preserve the User data stored in the stolen region. Hence this patch
> tries to identify presence of the RST device on the ACPI bus, and
> disables use of stolen memory (for persistent data) if found.
>
> v2: Updated comment, updated/corrected new functions private to driver
> (Chris/Tvrtko)
>
> v3: Disabling stolen by default, wait till required acpi changes to
> detect device presence are pulled in (Ankit)
>
> v4: Enabled stolen by default as required acpi changes are merged
> (Ankit)
>
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 11 +++++++++++
> drivers/gpu/drm/i915/i915_gem.c | 8 ++++++++
> drivers/gpu/drm/i915/i915_gem_stolen.c | 14 ++++++++++++++
> drivers/gpu/drm/i915/intel_acpi.c | 10 ++++++++++
> 4 files changed, 43 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 16f2f94..9d67097 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1349,6 +1349,16 @@ struct i915_gem_mm {
> */
> bool busy;
>
> + /**
> + * Stolen will be lost upon hibernate (as the memory is unpowered).
> + * Across resume, we expect stolen to be intact - however, it may
> + * also be utililised by third parties (e.g. Intel RapidStart
> + * Technology) and if so we have to assume that any data stored in
> + * stolen across resume is lost and we set this flag to indicate that
> + * the stolen memory is volatile.
> + */
> + bool nonvolatile_stolen;
> +
> /* the indicator for dispatch video commands on two BSD rings */
> unsigned int bsd_ring_dispatch_index;
>
> @@ -3465,6 +3475,7 @@ intel_opregion_notify_adapter(struct drm_device *dev, pci_power_t state)
> #endif
>
> /* intel_acpi.c */
> +bool intel_detect_acpi_rst(void);
> #ifdef CONFIG_ACPI
> extern void intel_register_dsm_handler(void);
> extern void intel_unregister_dsm_handler(void);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 0cd57d4..63dab63 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -396,8 +396,16 @@ static struct drm_i915_gem_object *
> i915_gem_alloc_object_stolen(struct drm_device *dev, size_t size)
> {
> struct drm_i915_gem_object *obj;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> int ret;
>
> + if (!dev_priv->mm.nonvolatile_stolen) {
> + /* Stolen may be overwritten by external parties
> + * so unsuitable for persistent user data.
> + */
> + return ERR_PTR(-ENODEV);
> + }
> +
> mutex_lock(&dev->struct_mutex);
> obj = i915_gem_object_create_stolen(dev, size);
> if (IS_ERR(obj))
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 335a1ef..4f44531 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -482,6 +482,20 @@ int i915_gem_init_stolen(struct drm_device *dev)
> */
> drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_usable_size);
>
> + /* If the stolen region can be modified behind our backs upon suspend,
> + * then we cannot use it to store nonvolatile contents (i.e user data)
> + * as it will be corrupted upon resume.
> + */
> + dev_priv->mm.nonvolatile_stolen = true;
> +#ifdef CONFIG_SUSPEND
> + if (intel_detect_acpi_rst()) {
> + /* BIOSes using RapidStart Technology have been reported
> + * to overwrite stolen across S3, not just S4.
> + */
> + dev_priv->mm.nonvolatile_stolen = false;
> + }
> +#endif
> +
I'd suggest simplifying it like this:
dev_priv->mm.nonvolatile_stolen = !(IS_ENABLED(CONFIG_SUSPEND) &&
acpi_dev_present("INT3392"));
And add to i915_gem_stolen.c:
#include <linux/acpi.h>
Best regards,
Lukas
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_acpi.c b/drivers/gpu/drm/i915/intel_acpi.c
> index eb638a1..67dc9b2 100644
> --- a/drivers/gpu/drm/i915/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/intel_acpi.c
> @@ -23,6 +23,11 @@ static const u8 intel_dsm_guid[] = {
> 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c
> };
>
> +static const struct acpi_device_id irst_ids[] = {
> + {"INT3392", 0},
> + {"", 0}
> +};
> +
> static char *intel_dsm_port_name(u8 id)
> {
> switch (id) {
> @@ -162,3 +167,8 @@ void intel_register_dsm_handler(void)
> void intel_unregister_dsm_handler(void)
> {
> }
> +
> +bool intel_detect_acpi_rst(void)
> +{
> + return acpi_dev_present(irst_ids[0].id);
> +}
> --
> 1.9.1
>
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