If the user bypasses i915 and accesses mmio directly, that easily confuses our automatic mmio debugging (any error we then detect is likely to be as a result of the user). Since we expect userspace to open debugfs/i915_forcewake_user if i915.ko is loaded and they want mmio access, that makes the opportune time to disable our debugging for duration of the bypass.
v2: Move the fiddling of uncore internals to uncore.c References: https://bugs.freedesktop.org/show_bug.cgi?id=102543 Signed-off-by: Chris Wilson <[email protected]> Cc: Mika Kuoppala <[email protected]> Reviewed-by: Mika Kuoppala <[email protected]> --- drivers/gpu/drm/i915/i915_debugfs.c | 19 ++++++++------ drivers/gpu/drm/i915/intel_uncore.c | 51 +++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_uncore.h | 10 ++++++++ 3 files changed, 72 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 48572b157222..87673efc52fe 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1421,6 +1421,9 @@ static int i915_forcewake_domains(struct seq_file *m, void *data) struct intel_uncore_forcewake_domain *fw_domain; unsigned int tmp; + seq_printf(m, "user.bypass_count = %u\n", + i915->uncore.user_forcewake.count); + for_each_fw_domain(fw_domain, i915, tmp) seq_printf(m, "%s.wake_count = %u\n", intel_uncore_forcewake_domain_to_str(fw_domain->id), @@ -4673,26 +4676,26 @@ static int i915_sseu_status(struct seq_file *m, void *unused) static int i915_forcewake_open(struct inode *inode, struct file *file) { - struct drm_i915_private *dev_priv = inode->i_private; + struct drm_i915_private *i915 = inode->i_private; - if (INTEL_GEN(dev_priv) < 6) + if (INTEL_GEN(i915) < 6) return 0; - intel_runtime_pm_get(dev_priv); - intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); + intel_runtime_pm_get(i915); + intel_uncore_forcewake_user_get(i915); return 0; } static int i915_forcewake_release(struct inode *inode, struct file *file) { - struct drm_i915_private *dev_priv = inode->i_private; + struct drm_i915_private *i915 = inode->i_private; - if (INTEL_GEN(dev_priv) < 6) + if (INTEL_GEN(i915) < 6) return 0; - intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); - intel_runtime_pm_put(dev_priv); + intel_uncore_forcewake_user_put(i915); + intel_runtime_pm_put(i915); return 0; } diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 0529af7cfbb8..1b38eb94d461 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -489,6 +489,57 @@ void intel_uncore_forcewake_get(struct drm_i915_private *dev_priv, spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); } +/** + * intel_uncore_forcewake_user_get - claim forcewake on behalf of userspace + * @dev_priv: i915 device instance + * + * This function is a wrapper around intel_uncore_forcewake_get() to acquire + * the GT powerwell and in the process disable our debugging for the + * duration of userspace's bypass. + */ +void intel_uncore_forcewake_user_get(struct drm_i915_private *dev_priv) +{ + spin_lock_irq(&dev_priv->uncore.lock); + if (!dev_priv->uncore.user_forcewake.count++) { + intel_uncore_forcewake_get__locked(dev_priv, FORCEWAKE_ALL); + + /* Save and disable mmio debugging for the user bypass */ + dev_priv->uncore.user_forcewake.saved_mmio_check = + dev_priv->uncore.unclaimed_mmio_check; + dev_priv->uncore.user_forcewake.saved_mmio_debug = + i915.mmio_debug; + + dev_priv->uncore.unclaimed_mmio_check = 0; + i915.mmio_debug = 0; + } + spin_unlock_irq(&dev_priv->uncore.lock); +} + +/** + * intel_uncore_forcewake_user_put - release forcewake on behalf of userspace + * @dev_priv: i915 device instance + * + * This function complements intel_uncore_forcewake_user_get() and releases + * the GT powerwell taken on behalf of the userspace bypass. + */ +void intel_uncore_forcewake_user_put(struct drm_i915_private *dev_priv) +{ + spin_lock_irq(&dev_priv->uncore.lock); + if (!--dev_priv->uncore.user_forcewake.count) { + if (intel_uncore_unclaimed_mmio(dev_priv)) + dev_info(dev_priv->drm.dev, + "Invalid mmio detected during user access\n"); + + dev_priv->uncore.unclaimed_mmio_check = + dev_priv->uncore.user_forcewake.saved_mmio_check; + i915.mmio_debug = + dev_priv->uncore.user_forcewake.saved_mmio_debug; + + intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL); + } + spin_unlock_irq(&dev_priv->uncore.lock); +} + /** * intel_uncore_forcewake_get__locked - grab forcewake domain references * @dev_priv: i915 device instance diff --git a/drivers/gpu/drm/i915/intel_uncore.h b/drivers/gpu/drm/i915/intel_uncore.h index 5f90278da461..03786f931905 100644 --- a/drivers/gpu/drm/i915/intel_uncore.h +++ b/drivers/gpu/drm/i915/intel_uncore.h @@ -102,6 +102,13 @@ struct intel_uncore { i915_reg_t reg_ack; } fw_domain[FW_DOMAIN_ID_COUNT]; + struct { + unsigned int count; + + int saved_mmio_check; + int saved_mmio_debug; + } user_forcewake; + int unclaimed_mmio_check; }; @@ -144,6 +151,9 @@ void intel_uncore_forcewake_get__locked(struct drm_i915_private *dev_priv, void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv, enum forcewake_domains domains); +void intel_uncore_forcewake_user_get(struct drm_i915_private *dev_priv); +void intel_uncore_forcewake_user_put(struct drm_i915_private *dev_priv); + int intel_wait_for_register(struct drm_i915_private *dev_priv, i915_reg_t reg, u32 mask, -- 2.14.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
