linux-kernel - [PATCH 2/4] bochs: add endian switching support

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>] [day] [month] [year] [list]

Date:	Wed, 19 Nov 2014 12:28:10 +0100
From:	Gerd Hoffmann <kraxel@...hat.com>
To:	dri-devel@...ts.freedesktop.org
Cc:	airlied@...hat.com, Gerd Hoffmann <kraxel@...hat.com>,
	David Airlie <airlied@...ux.ie>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 2/4] bochs: add endian switching support

Recently (qemu 2.2+) the qemu stdvga got a register to switch the vga
framebuffer endianness.  This patch adds code to explicitly set the
endianness of the framebuffer.  In most cases this has no effect as
the default is guest architecture endianness.  It is needed though in
case a architecture supports both big and little endian, i.e. for
ppc64le.

Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
---
 drivers/gpu/drm/bochs/bochs_hw.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bochs/bochs_hw.c b/drivers/gpu/drm/bochs/bochs_hw.c
index e8b1dac..4603897 100644
--- a/drivers/gpu/drm/bochs/bochs_hw.c
+++ b/drivers/gpu/drm/bochs/bochs_hw.c
@@ -51,7 +51,7 @@ int bochs_hw_init(struct drm_device *dev, uint32_t flags)
 {
 	struct bochs_device *bochs = dev->dev_private;
 	struct pci_dev *pdev = dev->pdev;
-	unsigned long addr, size, mem, ioaddr, iosize;
+	unsigned long addr, size, mem, ioaddr, iosize, qext_size;
 	u16 id;
 
 	if (pdev->resource[2].flags & IORESOURCE_MEM) {
@@ -115,6 +115,24 @@ int bochs_hw_init(struct drm_device *dev, uint32_t flags)
 		 size / 1024, addr,
 		 bochs->ioports ? "ioports" : "mmio",
 		 ioaddr);
+
+	if (bochs->mmio && pdev->revision >= 2) {
+		qext_size = readl(bochs->mmio + 0x600);
+		if (qext_size < 4 || qext_size > iosize)
+			goto noext;
+		DRM_DEBUG("Found qemu ext regs, size %ld\n", qext_size);
+		if (qext_size >= 8) {
+#ifdef __BIG_ENDIAN
+			writel(0xbebebebe, bochs->mmio + 0x604);
+#else
+			writel(0x1e1e1e1e, bochs->mmio + 0x604);
+#endif
+			DRM_DEBUG("  qext endian: 0x%x\n",
+				  readl(bochs->mmio + 0x604));
+		}
+	}
+
+noext:
 	return 0;
 }
 
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/