[1/2] switchtec: Fix false maximum supported PCIe function number issue
diff mbox series

Message ID 1554734088-5755-2-git-send-email-wesley.sheng@microchip.com
State Superseded
Headers show
Series
  • Fix two bugs of switchtec module
Related show

Commit Message

Wesley Sheng April 8, 2019, 2:34 p.m. UTC
The hardware supports up to 255 PFFs and the driver only supports 48, so
this patch updates the driver to support them all.
To be backward compatible, a new ioctl and corresponding data
structure are created, while keep the deprecated one.

Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com>
---
 drivers/pci/switch/switchtec.c       | 39 +++++++++++++++++++++++++-----------
 include/linux/switchtec.h            |  2 +-
 include/uapi/linux/switchtec_ioctl.h | 13 +++++++++++-
 3 files changed, 40 insertions(+), 14 deletions(-)

Comments

Bjorn Helgaas April 9, 2019, 10:36 p.m. UTC | #1
Hi Wesley,

On Mon, Apr 08, 2019 at 10:34:47PM +0800, Wesley Sheng wrote:
> The hardware supports up to 255 PFFs and the driver only supports 48, so
> this patch updates the driver to support them all.
> To be backward compatible, a new ioctl and corresponding data
> structure are created, while keep the deprecated one.

The above is either one paragraph that needs to be rewrapped, or two
paragraphs that need a blank line between.

What's a PFF?

> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com>
> ---
>  drivers/pci/switch/switchtec.c       | 39 +++++++++++++++++++++++++-----------
>  include/linux/switchtec.h            |  2 +-
>  include/uapi/linux/switchtec_ioctl.h | 13 +++++++++++-
>  3 files changed, 40 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
> index e22766c..7df9a69 100644
> --- a/drivers/pci/switch/switchtec.c
> +++ b/drivers/pci/switch/switchtec.c
> @@ -658,19 +658,25 @@ static int ioctl_flash_part_info(struct switchtec_dev *stdev,
>  
>  static int ioctl_event_summary(struct switchtec_dev *stdev,
>  	struct switchtec_user *stuser,
> -	struct switchtec_ioctl_event_summary __user *usum)
> +	struct switchtec_ioctl_event_summary __user *usum,
> +	size_t size)
>  {
> -	struct switchtec_ioctl_event_summary s = {0};
> +	struct switchtec_ioctl_event_summary *s;
>  	int i;
>  	u32 reg;
> +	int ret = 0;
>  
> -	s.global = ioread32(&stdev->mmio_sw_event->global_summary);
> -	s.part_bitmap = ioread32(&stdev->mmio_sw_event->part_event_bitmap);
> -	s.local_part = ioread32(&stdev->mmio_part_cfg->part_event_summary);
> +	s = kzalloc(sizeof(*s), GFP_KERNEL);
> +	if (!s)
> +		return -ENOMEM;
> +
> +	s->global = ioread32(&stdev->mmio_sw_event->global_summary);
> +	s->part_bitmap = ioread32(&stdev->mmio_sw_event->part_event_bitmap);
> +	s->local_part = ioread32(&stdev->mmio_part_cfg->part_event_summary);
>  
>  	for (i = 0; i < stdev->partition_count; i++) {
>  		reg = ioread32(&stdev->mmio_part_cfg_all[i].part_event_summary);
> -		s.part[i] = reg;
> +		s->part[i] = reg;
>  	}
>  
>  	for (i = 0; i < SWITCHTEC_MAX_PFF_CSR; i++) {
> @@ -679,15 +685,19 @@ static int ioctl_event_summary(struct switchtec_dev *stdev,
>  			break;
>  
>  		reg = ioread32(&stdev->mmio_pff_csr[i].pff_event_summary);
> -		s.pff[i] = reg;
> +		s->pff[i] = reg;
>  	}
>  
> -	if (copy_to_user(usum, &s, sizeof(s)))
> -		return -EFAULT;
> +	if (copy_to_user(usum, s, size)) {
> +		ret = -EFAULT;
> +		goto error_case;
> +	}
>  
>  	stuser->event_cnt = atomic_read(&stdev->event_cnt);
>  
> -	return 0;
> +error_case:
> +	kfree(s);
> +	return ret;
>  }
>  
>  static u32 __iomem *global_ev_reg(struct switchtec_dev *stdev,
> @@ -977,8 +987,9 @@ static long switchtec_dev_ioctl(struct file *filp, unsigned int cmd,
>  	case SWITCHTEC_IOCTL_FLASH_PART_INFO:
>  		rc = ioctl_flash_part_info(stdev, argp);
>  		break;
> -	case SWITCHTEC_IOCTL_EVENT_SUMMARY:
> -		rc = ioctl_event_summary(stdev, stuser, argp);
> +	case SWITCHTEC_IOCTL_EVENT_SUMMARY_LEGACY:
> +		rc = ioctl_event_summary(stdev, stuser, argp,
> +					 sizeof(struct switchtec_ioctl_event_summary_legacy));
>  		break;
>  	case SWITCHTEC_IOCTL_EVENT_CTL:
>  		rc = ioctl_event_ctl(stdev, argp);
> @@ -989,6 +1000,10 @@ static long switchtec_dev_ioctl(struct file *filp, unsigned int cmd,
>  	case SWITCHTEC_IOCTL_PORT_TO_PFF:
>  		rc = ioctl_port_to_pff(stdev, argp);
>  		break;
> +	case SWITCHTEC_IOCTL_EVENT_SUMMARY:
> +		rc = ioctl_event_summary(stdev, stuser, argp,
> +					 sizeof(struct switchtec_ioctl_event_summary));
> +		break;
>  	default:
>  		rc = -ENOTTY;
>  		break;
> diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h
> index 52a079b..0cfc34a 100644
> --- a/include/linux/switchtec.h
> +++ b/include/linux/switchtec.h
> @@ -20,7 +20,7 @@
>  #include <linux/cdev.h>
>  
>  #define SWITCHTEC_MRPC_PAYLOAD_SIZE 1024
> -#define SWITCHTEC_MAX_PFF_CSR 48
> +#define SWITCHTEC_MAX_PFF_CSR 255
>  
>  #define SWITCHTEC_EVENT_OCCURRED BIT(0)
>  #define SWITCHTEC_EVENT_CLEAR    BIT(0)
> diff --git a/include/uapi/linux/switchtec_ioctl.h b/include/uapi/linux/switchtec_ioctl.h
> index 4f4daf8..c912b5a 100644
> --- a/include/uapi/linux/switchtec_ioctl.h
> +++ b/include/uapi/linux/switchtec_ioctl.h
> @@ -50,7 +50,7 @@ struct switchtec_ioctl_flash_part_info {
>  	__u32 active;
>  };
>  
> -struct switchtec_ioctl_event_summary {
> +struct switchtec_ioctl_event_summary_legacy {
>  	__u64 global;
>  	__u64 part_bitmap;
>  	__u32 local_part;
> @@ -59,6 +59,15 @@ struct switchtec_ioctl_event_summary {
>  	__u32 pff[48];
>  };
>  
> +struct switchtec_ioctl_event_summary {
> +	__u64 global;
> +	__u64 part_bitmap;
> +	__u32 local_part;
> +	__u32 padding;
> +	__u32 part[48];
> +	__u32 pff[255];
> +};
> +
>  #define SWITCHTEC_IOCTL_EVENT_STACK_ERROR		0
>  #define SWITCHTEC_IOCTL_EVENT_PPU_ERROR			1
>  #define SWITCHTEC_IOCTL_EVENT_ISP_ERROR			2
> @@ -127,6 +136,8 @@ struct switchtec_ioctl_pff_port {
>  	_IOWR('W', 0x41, struct switchtec_ioctl_flash_part_info)
>  #define SWITCHTEC_IOCTL_EVENT_SUMMARY \
>  	_IOR('W', 0x42, struct switchtec_ioctl_event_summary)
> +#define SWITCHTEC_IOCTL_EVENT_SUMMARY_LEGACY \
> +	_IOR('W', 0x42, struct switchtec_ioctl_event_summary_legacy)

I'm not an ioctl expert.  Is the different struct size enough to
distinguish these two, since they're both ioctl number 0x42?

If I'm reading the patch right, a user program compiled against the
old header will continue working unchanged (with only 48 PFFs) even
though the kernel struct name changed from
switchtec_ioctl_event_summary to switchtec_ioctl_event_summary_legacy.

But if it is merely recompiled against the new header with no other
change, it will silently start using 255 PFFs.  I guess as long as it
uses "sizeof(switchtec_ioctl_event_summary.pff)" or similar, it should
work, but if it assumed an array size of 48, it will break.

No doubt this is all exactly what you intended, and if I understood
ioctls it would be obvious to me.  But it would be *more* obviously
backwards-compatible if you left the existing ioctl number and
structure the same and merely added a new
"SWITCHTEC_IOCTL_EVENT_SUMMARY_EXTENDED" with a new number and a new
struct.  So I'm just asking to be sure.

>  #define SWITCHTEC_IOCTL_EVENT_CTL \
>  	_IOWR('W', 0x43, struct switchtec_ioctl_event_ctl)
>  #define SWITCHTEC_IOCTL_PFF_TO_PORT \
> -- 
> 2.7.4
>
Logan Gunthorpe April 9, 2019, 11:32 p.m. UTC | #2
On 2019-04-09 4:36 p.m., Bjorn Helgaas wrote:
> Hi Wesley,
> 
> On Mon, Apr 08, 2019 at 10:34:47PM +0800, Wesley Sheng wrote:
>> The hardware supports up to 255 PFFs and the driver only supports 48, so
>> this patch updates the driver to support them all.
>> To be backward compatible, a new ioctl and corresponding data
>> structure are created, while keep the deprecated one.
> 
> The above is either one paragraph that needs to be rewrapped, or two
> paragraphs that need a blank line between.

Wesley can address this.

> What's a PFF?

PFF is really a concept internal to the Switchtec device. It stands for
PCIe Function Framework. Essentially, there is a bank of registers for
every PCIe Function (aka endpoint) in the switch. When I originally
wrote the driver, I assumed incorrectly there would only ever be one PFF
per port and the maximum number of ports for Switchtec parts is 48. In
fact, the hardware supports up to 255 and there are typically two PFFs
per upstream port (one for the port itself and one for the management
endpoint).

Logan

Patch
diff mbox series

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index e22766c..7df9a69 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -658,19 +658,25 @@  static int ioctl_flash_part_info(struct switchtec_dev *stdev,
 
 static int ioctl_event_summary(struct switchtec_dev *stdev,
 	struct switchtec_user *stuser,
-	struct switchtec_ioctl_event_summary __user *usum)
+	struct switchtec_ioctl_event_summary __user *usum,
+	size_t size)
 {
-	struct switchtec_ioctl_event_summary s = {0};
+	struct switchtec_ioctl_event_summary *s;
 	int i;
 	u32 reg;
+	int ret = 0;
 
-	s.global = ioread32(&stdev->mmio_sw_event->global_summary);
-	s.part_bitmap = ioread32(&stdev->mmio_sw_event->part_event_bitmap);
-	s.local_part = ioread32(&stdev->mmio_part_cfg->part_event_summary);
+	s = kzalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	s->global = ioread32(&stdev->mmio_sw_event->global_summary);
+	s->part_bitmap = ioread32(&stdev->mmio_sw_event->part_event_bitmap);
+	s->local_part = ioread32(&stdev->mmio_part_cfg->part_event_summary);
 
 	for (i = 0; i < stdev->partition_count; i++) {
 		reg = ioread32(&stdev->mmio_part_cfg_all[i].part_event_summary);
-		s.part[i] = reg;
+		s->part[i] = reg;
 	}
 
 	for (i = 0; i < SWITCHTEC_MAX_PFF_CSR; i++) {
@@ -679,15 +685,19 @@  static int ioctl_event_summary(struct switchtec_dev *stdev,
 			break;
 
 		reg = ioread32(&stdev->mmio_pff_csr[i].pff_event_summary);
-		s.pff[i] = reg;
+		s->pff[i] = reg;
 	}
 
-	if (copy_to_user(usum, &s, sizeof(s)))
-		return -EFAULT;
+	if (copy_to_user(usum, s, size)) {
+		ret = -EFAULT;
+		goto error_case;
+	}
 
 	stuser->event_cnt = atomic_read(&stdev->event_cnt);
 
-	return 0;
+error_case:
+	kfree(s);
+	return ret;
 }
 
 static u32 __iomem *global_ev_reg(struct switchtec_dev *stdev,
@@ -977,8 +987,9 @@  static long switchtec_dev_ioctl(struct file *filp, unsigned int cmd,
 	case SWITCHTEC_IOCTL_FLASH_PART_INFO:
 		rc = ioctl_flash_part_info(stdev, argp);
 		break;
-	case SWITCHTEC_IOCTL_EVENT_SUMMARY:
-		rc = ioctl_event_summary(stdev, stuser, argp);
+	case SWITCHTEC_IOCTL_EVENT_SUMMARY_LEGACY:
+		rc = ioctl_event_summary(stdev, stuser, argp,
+					 sizeof(struct switchtec_ioctl_event_summary_legacy));
 		break;
 	case SWITCHTEC_IOCTL_EVENT_CTL:
 		rc = ioctl_event_ctl(stdev, argp);
@@ -989,6 +1000,10 @@  static long switchtec_dev_ioctl(struct file *filp, unsigned int cmd,
 	case SWITCHTEC_IOCTL_PORT_TO_PFF:
 		rc = ioctl_port_to_pff(stdev, argp);
 		break;
+	case SWITCHTEC_IOCTL_EVENT_SUMMARY:
+		rc = ioctl_event_summary(stdev, stuser, argp,
+					 sizeof(struct switchtec_ioctl_event_summary));
+		break;
 	default:
 		rc = -ENOTTY;
 		break;
diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h
index 52a079b..0cfc34a 100644
--- a/include/linux/switchtec.h
+++ b/include/linux/switchtec.h
@@ -20,7 +20,7 @@ 
 #include <linux/cdev.h>
 
 #define SWITCHTEC_MRPC_PAYLOAD_SIZE 1024
-#define SWITCHTEC_MAX_PFF_CSR 48
+#define SWITCHTEC_MAX_PFF_CSR 255
 
 #define SWITCHTEC_EVENT_OCCURRED BIT(0)
 #define SWITCHTEC_EVENT_CLEAR    BIT(0)
diff --git a/include/uapi/linux/switchtec_ioctl.h b/include/uapi/linux/switchtec_ioctl.h
index 4f4daf8..c912b5a 100644
--- a/include/uapi/linux/switchtec_ioctl.h
+++ b/include/uapi/linux/switchtec_ioctl.h
@@ -50,7 +50,7 @@  struct switchtec_ioctl_flash_part_info {
 	__u32 active;
 };
 
-struct switchtec_ioctl_event_summary {
+struct switchtec_ioctl_event_summary_legacy {
 	__u64 global;
 	__u64 part_bitmap;
 	__u32 local_part;
@@ -59,6 +59,15 @@  struct switchtec_ioctl_event_summary {
 	__u32 pff[48];
 };
 
+struct switchtec_ioctl_event_summary {
+	__u64 global;
+	__u64 part_bitmap;
+	__u32 local_part;
+	__u32 padding;
+	__u32 part[48];
+	__u32 pff[255];
+};
+
 #define SWITCHTEC_IOCTL_EVENT_STACK_ERROR		0
 #define SWITCHTEC_IOCTL_EVENT_PPU_ERROR			1
 #define SWITCHTEC_IOCTL_EVENT_ISP_ERROR			2
@@ -127,6 +136,8 @@  struct switchtec_ioctl_pff_port {
 	_IOWR('W', 0x41, struct switchtec_ioctl_flash_part_info)
 #define SWITCHTEC_IOCTL_EVENT_SUMMARY \
 	_IOR('W', 0x42, struct switchtec_ioctl_event_summary)
+#define SWITCHTEC_IOCTL_EVENT_SUMMARY_LEGACY \
+	_IOR('W', 0x42, struct switchtec_ioctl_event_summary_legacy)
 #define SWITCHTEC_IOCTL_EVENT_CTL \
 	_IOWR('W', 0x43, struct switchtec_ioctl_event_ctl)
 #define SWITCHTEC_IOCTL_PFF_TO_PORT \