diff mbox

[v4,3/6] of: fix size when dma-range is not used

Message ID 1422052359-12384-4-git-send-email-m-karicheri2@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Murali Karicheri Jan. 23, 2015, 10:32 p.m. UTC
Fix the dma-range size when the DT attribute is missing. i.e  set size to
dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
overflow when mask is set to max of u64, add a check, log error and return.
Some platform use mask format for size in DTS. So add a work around to
catch this and fix.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 drivers/of/device.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Robin Murphy Jan. 27, 2015, 11:27 a.m. UTC | #1
Hi Murali,

On 23/01/15 22:32, Murali Karicheri wrote:
> Fix the dma-range size when the DT attribute is missing. i.e  set size to
> dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
> overflow when mask is set to max of u64, add a check, log error and return.
> Some platform use mask format for size in DTS. So add a work around to
> catch this and fix.
>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>
> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> ---
>   drivers/of/device.c |   14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index 2de320d..0a5ff54 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>   	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>   	if (ret < 0) {
>   		dma_addr = offset = 0;
> -		size = dev->coherent_dma_mask;
> +		size = dev->coherent_dma_mask + 1;
>   	} else {
>   		offset = PFN_DOWN(paddr - dma_addr);
> +		/*
> +		 * Add a work around to treat the size as mask + 1 in case
> +		 * it is defined in DT as a mask.
> +		 */
> +		if (size & 1)
> +			size = size + 1;
>   		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
>   	}
>
> +	/* if size is 0, we have an overflow of u64 */
> +	if (!size) {
> +		dev_err(dev, "invalid size\n");
> +		return;
> +	}
> +

This seems potentially fragile to dodgy DTs given that we might also be 
using size to make a mask later. Would it make sense to double-up a 
sanity check as mask-format detection? Something like:

if is_power_of_2(size)
	// use size
else if is_power_of_2(size + 1)
	// use size + 1
else
	// cry


Robin.

>   	dev->dma_pfn_offset = offset;
>
>   	coherent = of_dma_is_coherent(np);
>
Murali Karicheri Jan. 27, 2015, 3:44 p.m. UTC | #2
On 01/27/2015 06:27 AM, Robin Murphy wrote:
> Hi Murali,
>
> On 23/01/15 22:32, Murali Karicheri wrote:
>> Fix the dma-range size when the DT attribute is missing. i.e set size to
>> dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
>> overflow when mask is set to max of u64, add a check, log error and
>> return.
>> Some platform use mask format for size in DTS. So add a work around to
>> catch this and fix.
>>
>> Cc: Joerg Roedel <joro@8bytes.org>
>> Cc: Grant Likely <grant.likely@linaro.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> Cc: Arnd Bergmann <arnd@arndb.de>
>> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> ---
>> drivers/of/device.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/device.c b/drivers/of/device.c
>> index 2de320d..0a5ff54 100644
>> --- a/drivers/of/device.c
>> +++ b/drivers/of/device.c
>> @@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct
>> device_node *np)
>> ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>> if (ret < 0) {
>> dma_addr = offset = 0;
>> - size = dev->coherent_dma_mask;
>> + size = dev->coherent_dma_mask + 1;
>> } else {
>> offset = PFN_DOWN(paddr - dma_addr);
>> + /*
>> + * Add a work around to treat the size as mask + 1 in case
>> + * it is defined in DT as a mask.
>> + */
>> + if (size & 1)
>> + size = size + 1;
>> dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
>> }
>>
>> + /* if size is 0, we have an overflow of u64 */
>> + if (!size) {
>> + dev_err(dev, "invalid size\n");
>> + return;
>> + }
>> +
>
> This seems potentially fragile to dodgy DTs given that we might also be
> using size to make a mask later. Would it make sense to double-up a
> sanity check as mask-format detection? Something like:
>
> if is_power_of_2(size)
> // use size
> else if is_power_of_2(size + 1)
> // use size + 1
> else
> // cry
>
Robin,

I think this is better. I will wait for some more time for anyone to 
respond and re-send my patch with this change.

Thanks
Murali
>
> Robin.
>
>> dev->dma_pfn_offset = offset;
>>
>> coherent = of_dma_is_coherent(np);
>>
>
>
Murali Karicheri Jan. 27, 2015, 6:55 p.m. UTC | #3
On 01/27/2015 06:27 AM, Robin Murphy wrote:
> Hi Murali,
>
> On 23/01/15 22:32, Murali Karicheri wrote:
>> Fix the dma-range size when the DT attribute is missing. i.e set size to
>> dev->coherent_dma_mask + 1 instead of dev->coherent_dma_mask. To detect
>> overflow when mask is set to max of u64, add a check, log error and
>> return.
>> Some platform use mask format for size in DTS. So add a work around to
>> catch this and fix.
>>
>> Cc: Joerg Roedel <joro@8bytes.org>
>> Cc: Grant Likely <grant.likely@linaro.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> Cc: Arnd Bergmann <arnd@arndb.de>
>> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> ---
>> drivers/of/device.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/device.c b/drivers/of/device.c
>> index 2de320d..0a5ff54 100644
>> --- a/drivers/of/device.c
>> +++ b/drivers/of/device.c
>> @@ -105,12 +105,24 @@ void of_dma_configure(struct device *dev, struct
>> device_node *np)
>> ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>> if (ret < 0) {
>> dma_addr = offset = 0;
>> - size = dev->coherent_dma_mask;
>> + size = dev->coherent_dma_mask + 1;
>> } else {
>> offset = PFN_DOWN(paddr - dma_addr);
>> + /*
>> + * Add a work around to treat the size as mask + 1 in case
>> + * it is defined in DT as a mask.
>> + */
>> + if (size & 1)
>> + size = size + 1;
>> dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
>> }
>>
>> + /* if size is 0, we have an overflow of u64 */
>> + if (!size) {
>> + dev_err(dev, "invalid size\n");
>> + return;
>> + }
>> +
>
> This seems potentially fragile to dodgy DTs given that we might also be
> using size to make a mask later. Would it make sense to double-up a
> sanity check as mask-format detection? Something like:
>
> if is_power_of_2(size)
> // use size
> else if is_power_of_2(size + 1)
> // use size + 1
> else
> // cry
Robin,

How about having the logic like this?

	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
	if (ret < 0) {
		dma_addr = offset = 0;
		size = dev->coherent_dma_mask + 1;
	} else {
		offset = PFN_DOWN(paddr - dma_addr);
		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
	}

	if (is_power_of_2(size + 1))
		size = size + 1;
	else if (!is_power_of_2(size))
	{
		dev_err(dev, "invalid size\n");
		return;
	}

Murali
>
>
> Robin.
>
>> dev->dma_pfn_offset = offset;
>>
>> coherent = of_dma_is_coherent(np);
>>
>
>
diff mbox

Patch

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 2de320d..0a5ff54 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -105,12 +105,24 @@  void of_dma_configure(struct device *dev, struct device_node *np)
 	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
 	if (ret < 0) {
 		dma_addr = offset = 0;
-		size = dev->coherent_dma_mask;
+		size = dev->coherent_dma_mask + 1;
 	} else {
 		offset = PFN_DOWN(paddr - dma_addr);
+		/*
+		 * Add a work around to treat the size as mask + 1 in case
+		 * it is defined in DT as a mask.
+		 */
+		if (size & 1)
+			size = size + 1;
 		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
 	}
 
+	/* if size is 0, we have an overflow of u64 */
+	if (!size) {
+		dev_err(dev, "invalid size\n");
+		return;
+	}
+
 	dev->dma_pfn_offset = offset;
 
 	coherent = of_dma_is_coherent(np);