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[PATCH] pci: Update VPD size with correct length

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  [PATCH] pci: Update VPD size with correct length Hannes Reinecke <hare@suse.de> - 2015-10-23 11:20 +0200
    [RFC PATCH] pci: pci_vpd_pci22_size can be static kbuild test robot <lkp@intel.com> - 2015-10-23 12:50 +0200
    Re: [PATCH] pci: Update VPD size with correct length kbuild test robot <lkp@intel.com> - 2015-10-23 12:50 +0200
    Re: [PATCH] pci: Update VPD size with correct length Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-24 03:00 +0200
      Re: [PATCH] pci: Update VPD size with correct length Hannes Reinecke <hare@suse.de> - 2015-10-25 04:40 +0100

#1254418 — [PATCH] pci: Update VPD size with correct length

PCI-2.2 VPD entries have a maximum size of 32k, but might actually
be smaller than that. To figure out the actual size one has to read
the VPD area until the 'end marker' is reached.
Trying to read VPD data beyond that marker results in 'interesting'
effects, from simple read errors to crashing the card.
This path modifies the attribute size to the avialable VPD size.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/pci/access.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 6bc9b12..4f8208e 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -409,6 +409,34 @@ static int pci_vpd_f0_dev_check(struct pci_dev *dev)
 	return ret;
 }
 
+/**
+ * pci_vpd_size - determine actual size of Vital Product Data
+ * @dev:	pci device struct
+ * @old_size:	current assumed size, also maximum allowed size
+ *
+ */
+size_t
+pci_vpd_pci22_size(struct pci_dev *dev, size_t old_size)
+{
+	loff_t off = 0;
+	unsigned char header[1+2];	/* 1 byte tag, 2 bytes length */
+
+	while (off < old_size && pci_read_vpd(dev, off, 1, header)) {
+		if (header[0] == 0x78)	/* End tag descriptor */
+			return off + 1;
+		if (header[0] & 0x80) {
+			/* Large Resource Data Type Tag */
+			if (pci_read_vpd(dev, off+1, 2, &header[1]) != 2)
+				return off + 1;
+			off += 3 + ((header[2] << 8) | header[1]);
+		} else {
+			/* Short Resource Data Type Tag */
+			off += 1 + (header[0] & 0x07);
+		}
+	}
+	return old_size;
+}
+
 int pci_vpd_pci22_init(struct pci_dev *dev)
 {
 	struct pci_vpd_pci22 *vpd;
@@ -436,6 +464,7 @@ int pci_vpd_pci22_init(struct pci_dev *dev)
 	vpd->cap = cap;
 	vpd->busy = false;
 	dev->vpd = &vpd->base;
+	vpd->base.len = pci_vpd_pci22_size(dev, vpd->base.len);
 	return 0;
 }
 
-- 
1.8.5.6

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#1254476 — [RFC PATCH] pci: pci_vpd_pci22_size can be static

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
---
 access.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 3a49b14..41d86f6 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -495,7 +495,7 @@ static int pci_vpd_f0_dev_check(struct pci_dev *dev)
  * @old_size:	current assumed size, also maximum allowed size
  *
  */
-size_t
+static size_t
 pci_vpd_pci22_size(struct pci_dev *dev, size_t old_size)
 {
 	loff_t off = 0;
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#1254479

Hi Hannes,

[auto build test WARNING on pci/next -- if it's inappropriate base, please suggest rules for selecting the more suitable base]

url:    https://github.com/0day-ci/linux/commits/Hannes-Reinecke/pci-Update-VPD-size-with-correct-length/20151023-171224
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> drivers/pci/access.c:499:1: sparse: symbol 'pci_vpd_pci22_size' was not declared. Should it be static?

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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#1255078

On 10/23/2015 02:09 AM, Hannes Reinecke wrote:
> PCI-2.2 VPD entries have a maximum size of 32k, but might actually
> be smaller than that. To figure out the actual size one has to read
> the VPD area until the 'end marker' is reached.
> Trying to read VPD data beyond that marker results in 'interesting'
> effects, from simple read errors to crashing the card.
> This path modifies the attribute size to the avialable VPD size.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>   drivers/pci/access.c | 29 +++++++++++++++++++++++++++++
>   1 file changed, 29 insertions(+)
>
> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 6bc9b12..4f8208e 100644
> --- a/drivers/pci/access.c
> +++ b/drivers/pci/access.c
> @@ -409,6 +409,34 @@ static int pci_vpd_f0_dev_check(struct pci_dev *dev)
>   	return ret;
>   }
>
> +/**
> + * pci_vpd_size - determine actual size of Vital Product Data
> + * @dev:	pci device struct
> + * @old_size:	current assumed size, also maximum allowed size
> + *
> + */
> +size_t
> +pci_vpd_pci22_size(struct pci_dev *dev, size_t old_size)
> +{
> +	loff_t off = 0;
> +	unsigned char header[1+2];	/* 1 byte tag, 2 bytes length */
> +
> +	while (off < old_size && pci_read_vpd(dev, off, 1, header)) {
> +		if (header[0] == 0x78)	/* End tag descriptor */
> +			return off + 1;
> +		if (header[0] & 0x80) {
> +			/* Large Resource Data Type Tag */
> +			if (pci_read_vpd(dev, off+1, 2, &header[1]) != 2)
> +				return off + 1;
> +			off += 3 + ((header[2] << 8) | header[1]);
> +		} else {
> +			/* Short Resource Data Type Tag */
> +			off += 1 + (header[0] & 0x07);
> +		}
> +	}
> +	return old_size;
> +}
> +

My understanding is that the end tag can have some data associated with 
it such as a checksum.  What you may want to look at doing is process 
long tag and short tag bits first.  Then you could do a mask and compare 
after and if ((header[0] & ~0x7) == 0x78) then you return off + 1.

Also I was wondering if you have looked at the cxgb4 network driver? 
They are using the vpd read/write calls to access their EEPROM and I 
assume they are doing so outside the actual VPD fields.

- Alex
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#1255272

On 10/24/2015 02:52 AM, Alexander Duyck wrote:
> On 10/23/2015 02:09 AM, Hannes Reinecke wrote:
>> PCI-2.2 VPD entries have a maximum size of 32k, but might actually
>> be smaller than that. To figure out the actual size one has to read
>> the VPD area until the 'end marker' is reached.
>> Trying to read VPD data beyond that marker results in 'interesting'
>> effects, from simple read errors to crashing the card.
>> This path modifies the attribute size to the avialable VPD size.
>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>   drivers/pci/access.c | 29 +++++++++++++++++++++++++++++
>>   1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
>> index 6bc9b12..4f8208e 100644
>> --- a/drivers/pci/access.c
>> +++ b/drivers/pci/access.c
>> @@ -409,6 +409,34 @@ static int pci_vpd_f0_dev_check(struct pci_dev *dev)
>>       return ret;
>>   }
>>
>> +/**
>> + * pci_vpd_size - determine actual size of Vital Product Data
>> + * @dev:    pci device struct
>> + * @old_size:    current assumed size, also maximum allowed size
>> + *
>> + */
>> +size_t
>> +pci_vpd_pci22_size(struct pci_dev *dev, size_t old_size)
>> +{
>> +    loff_t off = 0;
>> +    unsigned char header[1+2];    /* 1 byte tag, 2 bytes length */
>> +
>> +    while (off < old_size && pci_read_vpd(dev, off, 1, header)) {
>> +        if (header[0] == 0x78)    /* End tag descriptor */
>> +            return off + 1;
>> +        if (header[0] & 0x80) {
>> +            /* Large Resource Data Type Tag */
>> +            if (pci_read_vpd(dev, off+1, 2, &header[1]) != 2)
>> +                return off + 1;
>> +            off += 3 + ((header[2] << 8) | header[1]);
>> +        } else {
>> +            /* Short Resource Data Type Tag */
>> +            off += 1 + (header[0] & 0x07);
>> +        }
>> +    }
>> +    return old_size;
>> +}
>> +
> 
> My understanding is that the end tag can have some data associated with
> it such as a checksum.  What you may want to look at doing is process
> long tag and short tag bits first.  Then you could do a mask and compare
> after and if ((header[0] & ~0x7) == 0x78) then you return off + 1.
> 
Ah. Oh. Hmm. Wasn't aware of that one.
Bjorn?

> Also I was wondering if you have looked at the cxgb4 network driver?
> They are using the vpd read/write calls to access their EEPROM and I
> assume they are doing so outside the actual VPD fields.
> 
As indicated; VPD page access is basically directly wired to the device.
So if the vendor chooses to do some extra magic there by all means let
him do so. This patch is meant for cards/vendors which (try) to adhere
to the PCI VPD specification, so our access to that should be
conformant, too.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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