From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
Tudor Ambarus <Tudor.Ambarus@microchip.com>,
Richard Weinberger <richard@nod.at>,
stable@vger.kernel.org, Marek Vasut <marek.vasut@gmail.com>,
Boris Brezillon <boris.brezillon@collabora.com>,
linux-mtd@lists.infradead.org,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Brian Norris <computersforpeace@gmail.com>,
David Woodhouse <dwmw2@infradead.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] mtd: spear_smi: Fix nonalignment not handled in memcpy_toio
Date: Tue, 22 Oct 2019 09:26:43 +0100 [thread overview]
Message-ID: <20191022082643.GO25745@shell.armlinux.org.uk> (raw)
In-Reply-To: <20191018143643.29676-1-miquel.raynal@bootlin.com>
On Fri, Oct 18, 2019 at 04:36:43PM +0200, Miquel Raynal wrote:
> Any write with either dd or flashcp to a device driven by the
> spear_smi.c driver will pass through the spear_smi_cpy_toio()
> function. This function will get called for chunks of up to 256 bytes.
> If the amount of data is smaller, we may have a problem if the data
> length is not 4-byte aligned. In this situation, the kernel panics
> during the memcpy:
>
> # dd if=/dev/urandom bs=1001 count=1 of=/dev/mtd6
> spear_smi_cpy_toio [620] dest c9070000, src c7be8800, len 256
> spear_smi_cpy_toio [620] dest c9070100, src c7be8900, len 256
> spear_smi_cpy_toio [620] dest c9070200, src c7be8a00, len 256
> spear_smi_cpy_toio [620] dest c9070300, src c7be8b00, len 233
> Unhandled fault: external abort on non-linefetch (0x808) at 0xc90703e8
> [...]
> PC is at memcpy+0xcc/0x330
I need the full oops if you want me to comment on this.
>
> Workaround this issue by using the alternate _memcpy_toio() method
> which at least does not present the same problem.
>
> Fixes: f18dbbb1bfe0 ("mtd: ST SPEAr: Add SMI driver for serial NOR flash")
> Cc: stable@vger.kernel.org
> Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>
> Hello,
>
> This patch could not be tested with a mainline kernel (only compiled)
> but was tested with a stable 4.14.x kernel. I have really no idea why
> memcpy fails in this situation that's why I propose this workaround
> but I bet there is something deeper not working.
>
> Thanks,
> Miquèl
>
> drivers/mtd/devices/spear_smi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
> index 986f81d2f93e..d888625a3244 100644
> --- a/drivers/mtd/devices/spear_smi.c
> +++ b/drivers/mtd/devices/spear_smi.c
> @@ -614,7 +614,7 @@ static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
> ctrlreg1 = readl(dev->io_base + SMI_CR1);
> writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1);
>
> - memcpy_toio(dest, src, len);
> + _memcpy_toio(dest, src, len);
>
> writel(ctrlreg1, dev->io_base + SMI_CR1);
>
> --
> 2.20.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
--
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next prev parent reply other threads:[~2019-10-22 8:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 14:36 [PATCH] mtd: spear_smi: Fix nonalignment not handled in memcpy_toio Miquel Raynal
2019-10-18 14:49 ` Miquel Raynal
2019-10-21 8:01 ` Boris Brezillon
2019-10-22 7:44 ` Miquel Raynal
2019-10-22 7:51 ` Miquel Raynal
2019-10-22 7:52 ` Thomas Petazzoni
2019-10-22 8:26 ` Russell King - ARM Linux admin [this message]
2019-10-22 9:17 ` Miquel Raynal
2019-10-22 9:26 ` Russell King - ARM Linux admin
2019-10-22 9:47 ` Miquel Raynal
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