linux-kernel - [PATCH 3.16 278/410] drm/radeon: insist on 32-bit DMA for Cedar on PPC64/PPC64LE

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: <lsq.1528380321.665890176@decadent.org.uk>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Ben Crocker" <bcrocker@...hat.com>,
        "Alex Deucher" <alexander.deucher@....com>
Subject: [PATCH 3.16 278/410] drm/radeon: insist on 32-bit DMA for Cedar
 on PPC64/PPC64LE

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Crocker <bcrocker@...hat.com>

commit 2c83029cda55a5e7665c7c6326909427d6a01350 upstream.

In radeon_device_init, set the need_dma32 flag for Cedar chips
(e.g. FirePro 2270).  This fixes, or at least works around, a bug
on PowerPC exposed by last year's commits

8e3f1b1d8255105f31556aacf8aeb6071b00d469 (Russell Currey)

and

253fd51e2f533552ae35a0c661705da6c4842c1b (Alistair Popple)

which enabled the 64-bit DMA iommu bypass.

This caused the device to freeze, in some cases unrecoverably, and is
the subject of several bug reports internal to Red Hat.

Signed-off-by: Ben Crocker <bcrocker@...hat.com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpu/drm/radeon/radeon_device.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1339,6 +1339,10 @@ int radeon_device_init(struct radeon_dev
 	if ((rdev->flags & RADEON_IS_PCI) &&
 	    (rdev->family <= CHIP_RS740))
 		rdev->need_dma32 = true;
+#ifdef CONFIG_PPC64
+	if (rdev->family == CHIP_CEDAR)
+		rdev->need_dma32 = true;
+#endif
 
 	dma_bits = rdev->need_dma32 ? 32 : 40;
 	r = pci_set_dma_mask(rdev->pdev, DMA_BIT_MASK(dma_bits));