From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org,
bcm-kernel-feedback-list@broadcom.com,
linux-rpi-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Cc: hch@infradead.org, mbrugger@suse.com, f.fainelli@gmail.com,
wahrenst@gmx.net, Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Russell King <linux@armlinux.org.uk>
Subject: [PATCH RFC 4/5] dma/direct: check for overflows in ARM's dma_capable()
Date: Mon, 14 Oct 2019 20:31:06 +0200 [thread overview]
Message-ID: <20191014183108.24804-5-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20191014183108.24804-1-nsaenzjulienne@suse.de>
The Raspberry Pi 4 has a 1GB ZONE_DMA area starting at address
0x00000000 and a mapping between physical and DMA memory offset by
0xc0000000. It transpires that, on non LPAE systems, any attempt to
translate physical addresses outside of ZONE_DMA will result in an
overflow. The resulting DMA addresses will not be detected by arm's
dma_capable() as they still fit in the device's DMA mask.
Fix this by failing to validate a DMA address smaller than the lowest
possible DMA address.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
arch/arm/include/asm/dma-direct.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
index b67e5fc1fe43..ee8ad47a14e3 100644
--- a/arch/arm/include/asm/dma-direct.h
+++ b/arch/arm/include/asm/dma-direct.h
@@ -2,6 +2,8 @@
#ifndef ASM_ARM_DMA_DIRECT_H
#define ASM_ARM_DMA_DIRECT_H 1
+#include <linux/memblock.h>
+
static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
{
unsigned int offset = paddr & ~PAGE_MASK;
@@ -21,6 +23,10 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
if (!dev->dma_mask)
return 0;
+ /* Check if address overflowed */
+ if (addr < __phys_to_dma(dev, PFN_UP(min_low_pfn)))
+ return 0;
+
mask = *dev->dma_mask;
limit = (mask + 1) & ~mask;
--
2.23.0
next prev parent reply other threads:[~2019-10-14 18:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-14 18:31 [PATCH RFC 0/5] ARM: Raspberry Pi 4 DMA support Nicolas Saenz Julienne
2019-10-14 18:31 ` [PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable Nicolas Saenz Julienne
2019-10-30 21:49 ` Christoph Hellwig
2019-10-31 10:30 ` Nicolas Saenz Julienne
2019-10-31 13:38 ` Christoph Hellwig
2019-10-31 17:26 ` Nicolas Saenz Julienne
2019-10-14 18:31 ` [PATCH RFC 2/5] ARM: introduce arm_dma_direct Nicolas Saenz Julienne
2019-10-15 10:04 ` Christoph Hellwig
2019-10-14 18:31 ` [PATCH RFC 3/5] ARM: let machines select dma-direct over arch's DMA implementation Nicolas Saenz Julienne
2019-10-14 18:31 ` Nicolas Saenz Julienne [this message]
2019-10-15 10:23 ` [PATCH RFC 4/5] dma/direct: check for overflows in ARM's dma_capable() Christoph Hellwig
2019-10-15 13:07 ` Nicolas Saenz Julienne
2019-10-14 18:31 ` [PATCH RFC 5/5] ARM: bcm2711: use dma-direct Nicolas Saenz Julienne
2019-10-14 20:59 ` [PATCH RFC 0/5] ARM: Raspberry Pi 4 DMA support Catalin Marinas
2019-10-15 7:48 ` Nicolas Saenz Julienne
2019-10-15 17:46 ` Catalin Marinas
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