linux-kernel - [PATCH v4 06/18] drm/imagination: Mask GPU IRQs in threaded handler

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250320-sets-bxs-4-64-patch-v1-v4-6-d987cf4ca439@imgtec.com>
Date: Thu, 20 Mar 2025 11:32:16 +0000
From: Matt Coster <matt.coster@...tec.com>
To: Frank Binns <frank.binns@...tec.com>,
        Matt Coster
	<matt.coster@...tec.com>,
        David Airlie <airlied@...il.com>, Simona Vetter
	<simona@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Nishanth Menon <nm@...com>,
        "Vignesh
 Raghavendra" <vigneshr@...com>,
        Tero Kristo <kristo@...nel.org>
CC: <dri-devel@...ts.freedesktop.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
        Randolph Sapp <rs@...com>, Darren Etheridge <detheridge@...com>,
        "Michal
 Wilczynski" <m.wilczynski@...sung.com>,
        Alessio Belle
	<alessio.belle@...tec.com>,
        Alexandru Dadu <alexandru.dadu@...tec.com>
Subject: [PATCH v4 06/18] drm/imagination: Mask GPU IRQs in threaded
 handler

From: Alessio Belle <alessio.belle@...tec.com>

Pass IRQF_ONESHOT flag to request_threaded_irq(), so that interrupts will
be masked by the kernel until the end of the threaded IRQ handler. Since
the calls to pvr_fw_irq_enable() and pvr_fw_irq_disable() are now
redundant, remove them.

Interrupts to the host from the soon-to-be-added RISC-V firmware
processors cannot be masked in hardware. This change allows us to continue
using the threaded handler in GPUs with a RISC-V firmware.

For simplicity, the same approach is taken for all firmware processors.

Signed-off-by: Alessio Belle <alessio.belle@...tec.com>
Signed-off-by: Matt Coster <matt.coster@...tec.com>
---
Changes in v4:
- None
- Link to v3: https://lore.kernel.org/r/20250310-sets-bxs-4-64-patch-v1-v3-6-143b3dbef02f@imgtec.com
Changes in v3:
- Added
---
 drivers/gpu/drm/imagination/pvr_device.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/imagination/pvr_device.c b/drivers/gpu/drm/imagination/pvr_device.c
index 1704c0268589bdeb65fa6535f9ec63182b0a3e94..b6ce936f07c8bb26d240e50b72a1d991dbe4b045 100644
--- a/drivers/gpu/drm/imagination/pvr_device.c
+++ b/drivers/gpu/drm/imagination/pvr_device.c
@@ -169,8 +169,6 @@ static irqreturn_t pvr_device_irq_thread_handler(int irq, void *data)
 		ret = IRQ_HANDLED;
 	}
 
-	/* Unmask FW irqs before returning, so new interrupts can be received. */
-	pvr_fw_irq_enable(pvr_dev);
 	return ret;
 }
 
@@ -181,10 +179,6 @@ static irqreturn_t pvr_device_irq_handler(int irq, void *data)
 	if (!pvr_fw_irq_pending(pvr_dev))
 		return IRQ_NONE; /* Spurious IRQ - ignore. */
 
-	/* Mask the FW interrupts before waking up the thread. Will be unmasked
-	 * when the thread handler is done processing events.
-	 */
-	pvr_fw_irq_disable(pvr_dev);
 	return IRQ_WAKE_THREAD;
 }
 
@@ -213,9 +207,13 @@ pvr_device_irq_init(struct pvr_device *pvr_dev)
 	pvr_fw_irq_clear(pvr_dev);
 	pvr_fw_irq_enable(pvr_dev);
 
+	/*
+	 * The ONESHOT flag ensures IRQs are masked while the thread handler is
+	 * running.
+	 */
 	return request_threaded_irq(pvr_dev->irq, pvr_device_irq_handler,
 				    pvr_device_irq_thread_handler,
-				    IRQF_SHARED, "gpu", pvr_dev);
+				    IRQF_SHARED | IRQF_ONESHOT, "gpu", pvr_dev);
 }
 
 /**

-- 
2.49.0