diff mbox series

[v4,45/47] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K

Message ID 20191108130123.6839-46-linux@rasmusvillemoes.dk (mailing list archive)
State Not Applicable
Headers show
Series QUICC Engine support on ARM and ARM64 | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (85c5b0984ebb104ec7a0a853ec1e63c19f500313)
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 11 lines checked

Commit Message

Rasmus Villemoes Nov. 8, 2019, 1:01 p.m. UTC
Qiang Zhao points out that these offsets get written to 16-bit
registers, and there are some QE platforms with more than 64K
muram. So it is possible that qe_muram_alloc() gives us an allocation
that can't actually be used by the hardware, so detect and reject
that.

Reported-by: Qiang Zhao <qiang.zhao@nxp.com>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/net/wan/fsl_ucc_hdlc.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Timur Tabi Nov. 15, 2019, 4:41 a.m. UTC | #1
On Fri, Nov 8, 2019 at 7:04 AM Rasmus Villemoes
<linux@rasmusvillemoes.dk> wrote:

> diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
> index 8d13586bb774..f029eaa7cfc0 100644
> --- a/drivers/net/wan/fsl_ucc_hdlc.c
> +++ b/drivers/net/wan/fsl_ucc_hdlc.c
> @@ -245,6 +245,11 @@ static int uhdlc_init(struct ucc_hdlc_private *priv)
>                 ret = -ENOMEM;
>                 goto free_riptr;
>         }
> +       if (riptr != (u16)riptr || tiptr != (u16)tiptr) {

"riptr/tiptr > U16_MAX" is clearer.
Rasmus Villemoes Nov. 15, 2019, 7:44 a.m. UTC | #2
On 15/11/2019 05.41, Timur Tabi wrote:
> On Fri, Nov 8, 2019 at 7:04 AM Rasmus Villemoes
> <linux@rasmusvillemoes.dk> wrote:
> 
>> diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
>> index 8d13586bb774..f029eaa7cfc0 100644
>> --- a/drivers/net/wan/fsl_ucc_hdlc.c
>> +++ b/drivers/net/wan/fsl_ucc_hdlc.c
>> @@ -245,6 +245,11 @@ static int uhdlc_init(struct ucc_hdlc_private *priv)
>>                 ret = -ENOMEM;
>>                 goto free_riptr;
>>         }
>> +       if (riptr != (u16)riptr || tiptr != (u16)tiptr) {
> 
> "riptr/tiptr > U16_MAX" is clearer.
> 

I can change it, sure, but it's a matter of taste. To me the above asks
"does the value change when it is truncated to a u16" which makes
perfect sense when the value is next used with iowrite16be(). Using a
comparison to U16_MAX takes more brain cycles for me, because I have to
think whether it should be > or >=, and are there some
signedness/integer promotion business interfering with that test.

Rasmus
Timur Tabi Nov. 15, 2019, 2:33 p.m. UTC | #3
On 11/15/19 1:44 AM, Rasmus Villemoes wrote:
> I can change it, sure, but it's a matter of taste. To me the above asks
> "does the value change when it is truncated to a u16" which makes
> perfect sense when the value is next used with iowrite16be(). Using a
> comparison to U16_MAX takes more brain cycles for me, because I have to
> think whether it should be > or >=, and are there some
> signedness/integer promotion business interfering with that test.

Ok.
diff mbox series

Patch

diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
index 8d13586bb774..f029eaa7cfc0 100644
--- a/drivers/net/wan/fsl_ucc_hdlc.c
+++ b/drivers/net/wan/fsl_ucc_hdlc.c
@@ -245,6 +245,11 @@  static int uhdlc_init(struct ucc_hdlc_private *priv)
 		ret = -ENOMEM;
 		goto free_riptr;
 	}
+	if (riptr != (u16)riptr || tiptr != (u16)tiptr) {
+		dev_err(priv->dev, "MURAM allocation out of addressable range\n");
+		ret = -ENOMEM;
+		goto free_tiptr;
+	}
 
 	/* Set RIPTR, TIPTR */
 	iowrite16be(riptr, &priv->ucc_pram->riptr);