[PATCH 1/2] remoteproc: bail out if firmware has different endianess

[PATCH 1/2] remoteproc: bail out if firmware has different endianess

[Ohad Ben-Cohen]

At this point we don't support remote processors that have
a different endianess than the host.

Look out for these unsupported scenarios, and bail out if
encountered.

Reported-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Mark Grosen <mgrosen@ti.com>
---
 drivers/remoteproc/remoteproc_core.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 6212b82..567a3c5 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -39,6 +39,7 @@
 #include <linux/elf.h>
 #include <linux/virtio_ids.h>
 #include <linux/virtio_ring.h>
+#include <asm/byteorder.h>
 
 #include "remoteproc_internal.h"
 
@@ -851,6 +852,16 @@ static int rproc_fw_sanity_check(struct rproc *rproc, const struct firmware *fw)
 
 	ehdr = (struct elf32_hdr *)fw->data;
 
+	/* We assume the firmware has the same endianess as the host */
+# ifdef __LITTLE_ENDIAN
+	if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
+# else /* BIG ENDIAN */
+	if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
+# endif
+		dev_err(dev, "Unsupported firmware endianess\n");
+		return -EINVAL;
+	}
+
 	if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
 		dev_err(dev, "Image is too small\n");
 		return -EINVAL;
-- 
1.7.5.4

[PATCH 2/2] remoteproc: s/big switch/lookup table/

[Ohad Ben-Cohen]

A lookup table would be easier to extend, and the resulting
code is a bit cleaner.

Reported-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
---
 drivers/remoteproc/remoteproc_core.c |   45 +++++++++++++++++----------------
 include/linux/remoteproc.h           |    7 +++++
 2 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 567a3c5..94473bd 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -64,6 +64,8 @@ static DEFINE_KLIST(rprocs, klist_rproc_get, klist_rproc_put);
 
 typedef int (*rproc_handle_resources_t)(struct rproc *rproc,
 				struct fw_resource *rsc, int len);
+typedef int (*rproc_handle_resource_t)(struct rproc *rproc,
+				struct fw_resource *rsc);
 
 /*
  * This is the IOMMU fault handler we register with the IOMMU API
@@ -658,44 +660,43 @@ free_mapping:
 	return ret;
 }
 
+/*
+ * A lookup table for resource handlers. Always keep in sync with
+ * enum fw_resource_type.
+ */
+static rproc_handle_resource_t rproc_handle_rsc[] = {
+	rproc_handle_carveout,	/* RSC_CARVEOUT */
+	rproc_handle_devmem,	/* RSC_DEVMEM */
+	rproc_handle_trace,	/* RSC_TRACE */
+	rproc_handle_vring,	/* RSC_VRING */
+	NULL, /* RSC_VIRTIO_DEV is handled early upon registration */
+};
+
 /* handle firmware resource entries before booting the remote processor */
 static int
 rproc_handle_boot_rsc(struct rproc *rproc, struct fw_resource *rsc, int len)
 {
 	struct device *dev = rproc->dev;
+	rproc_handle_resource_t handler;
 	int ret = 0;
 
-	while (len >= sizeof(*rsc)) {
+	for (; len >= sizeof(*rsc); rsc++, len -= sizeof(*rsc)) {
 		dev_dbg(dev, "rsc: type %d, da 0x%llx, pa 0x%llx, len 0x%x, "
 			"id %d, name %s, flags %x\n", rsc->type, rsc->da,
 			rsc->pa, rsc->len, rsc->id, rsc->name, rsc->flags);
 
-		switch (rsc->type) {
-		case RSC_CARVEOUT:
-			ret = rproc_handle_carveout(rproc, rsc);
-			break;
-		case RSC_DEVMEM:
-			ret = rproc_handle_devmem(rproc, rsc);
-			break;
-		case RSC_TRACE:
-			ret = rproc_handle_trace(rproc, rsc);
-			break;
-		case RSC_VRING:
-			ret = rproc_handle_vring(rproc, rsc);
-			break;
-		case RSC_VIRTIO_DEV:
-			/* this one is handled early upon registration */
-			break;
-		default:
+		if (rsc->type >= RSC_LAST) {
 			dev_warn(dev, "unsupported resource %d\n", rsc->type);
-			break;
+			continue;
 		}
 
+		handler = rproc_handle_rsc[rsc->type];
+		if (!handler)
+			continue;
+
+		ret = handler(rproc, rsc);
 		if (ret)
 			break;
-
-		rsc++;
-		len -= sizeof(*rsc);
 	}
 
 	return ret;
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index b52f784..2544d2e 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -103,6 +103,7 @@ struct fw_resource {
  *		    the virtio device features, 'pa' holds the virtio guest
  *		    features, 'len' holds the virtio status, and 'flags' holds
  *		    the virtio id (currently only VIRTIO_ID_RPMSG is supported).
+ * @RSC_LAST:       just keep this one at the end
  *
  * Most of the resource entries share the basic idea of address/length
  * negotiation with the host: the firmware usually asks (on behalf of the
@@ -115,6 +116,11 @@ struct fw_resource {
  * will contain the expected device addresses (today we actually only support
  * this scheme, as there aren't yet any use cases for dynamically allocated
  * device addresses).
+ *
+ * Please note that these values are used as indices to the
+ * rproc_handle_rsc lookup table, so please keep the two synchronized.
+ * @RSC_LAST is used to check the validity of an index before the lookup table
+ * is accessed, so please update it as needed too.
  */
 enum fw_resource_type {
 	RSC_CARVEOUT	= 0,
@@ -122,6 +128,7 @@ enum fw_resource_type {
 	RSC_TRACE	= 2,
 	RSC_VRING	= 3,
 	RSC_VIRTIO_DEV	= 4,
+	RSC_LAST	= 5,
 };
 
 /**
-- 
1.7.5.4

Re: [PATCH 2/2] remoteproc: s/big switch/lookup table/

[Jack Stone]

On 31/01/12 16:52, Ohad Ben-Cohen wrote:
> +/*
> + * A lookup table for resource handlers. Always keep in sync with
> + * enum fw_resource_type.
> + */
> +static rproc_handle_resource_t rproc_handle_rsc[] = {
> +	rproc_handle_carveout,	/* RSC_CARVEOUT */
> +	rproc_handle_devmem,	/* RSC_DEVMEM */
> +	rproc_handle_trace,	/* RSC_TRACE */
> +	rproc_handle_vring,	/* RSC_VRING */
> +	NULL, /* RSC_VIRTIO_DEV is handled early upon registration */
> +};
> +

You could change this to

[RSC_CARVEOUT] = rproc_handle_carveout,

Then you would be safe against renumbering and would only need to worry
about addition (which your RSC_LAST check copes with).

Thanks,

Jack

Re: [PATCH 2/2] remoteproc: s/big switch/lookup table/

[Grant Likely]

On Tue, Jan 31, 2012 at 05:58:10PM +0000, Jack Stone wrote:
> On 31/01/12 16:52, Ohad Ben-Cohen wrote:
> > +/*
> > + * A lookup table for resource handlers. Always keep in sync with
> > + * enum fw_resource_type.
> > + */
> > +static rproc_handle_resource_t rproc_handle_rsc[] = {
> > +	rproc_handle_carveout,	/* RSC_CARVEOUT */
> > +	rproc_handle_devmem,	/* RSC_DEVMEM */
> > +	rproc_handle_trace,	/* RSC_TRACE */
> > +	rproc_handle_vring,	/* RSC_VRING */
> > +	NULL, /* RSC_VIRTIO_DEV is handled early upon registration */
> > +};
> > +
> 
> You could change this to
> 
> [RSC_CARVEOUT] = rproc_handle_carveout,
> 
> Then you would be safe against renumbering and would only need to worry
> about addition (which your RSC_LAST check copes with).

Yes, that is the right thing to do.  Then the compiler can catch ordering
issues for you.

g.

Re: [PATCH 1/2] remoteproc: bail out if firmware has different endianess

[Grant Likely]

On Tue, Jan 31, 2012 at 06:52:41PM +0200, Ohad Ben-Cohen wrote:
> At this point we don't support remote processors that have
> a different endianess than the host.
> 
> Look out for these unsupported scenarios, and bail out if
> encountered.
> 
> Reported-by: Grant Likely <grant.likely@secretlab.ca>
> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
> Cc: Mark Grosen <mgrosen@ti.com>

Acked-by: Grant Likely <grant.likely@secretlab.ca>

> ---
>  drivers/remoteproc/remoteproc_core.c |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 6212b82..567a3c5 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -39,6 +39,7 @@
>  #include <linux/elf.h>
>  #include <linux/virtio_ids.h>
>  #include <linux/virtio_ring.h>
> +#include <asm/byteorder.h>
>  
>  #include "remoteproc_internal.h"
>  
> @@ -851,6 +852,16 @@ static int rproc_fw_sanity_check(struct rproc *rproc, const struct firmware *fw)
>  
>  	ehdr = (struct elf32_hdr *)fw->data;
>  
> +	/* We assume the firmware has the same endianess as the host */
> +# ifdef __LITTLE_ENDIAN
> +	if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
> +# else /* BIG ENDIAN */
> +	if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
> +# endif
> +		dev_err(dev, "Unsupported firmware endianess\n");
> +		return -EINVAL;
> +	}
> +
>  	if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
>  		dev_err(dev, "Image is too small\n");
>  		return -EINVAL;
> -- 
> 1.7.5.4
> 

Re: [PATCH 2/2] remoteproc: s/big switch/lookup table/

[Ohad Ben-Cohen]

On Tue, Jan 31, 2012 at 10:08 PM, Grant Likely
<grant.likely@secretlab.ca> wrote:
> On Tue, Jan 31, 2012 at 05:58:10PM +0000, Jack Stone wrote:
>> On 31/01/12 16:52, Ohad Ben-Cohen wrote:
>> [RSC_CARVEOUT] = rproc_handle_carveout,

That looks great.

Thanks!

Re: [PATCH 1/2] remoteproc: bail out if firmware has different endianess

[Ohad Ben-Cohen]

On Tue, Jan 31, 2012 at 10:09 PM, Grant Likely
<grant.likely@secretlab.ca> wrote:
> On Tue, Jan 31, 2012 at 06:52:41PM +0200, Ohad Ben-Cohen wrote:
>> At this point we don't support remote processors that have
>> a different endianess than the host.
>>
>> Look out for these unsupported scenarios, and bail out if
>> encountered.
>>
>> Reported-by: Grant Likely <grant.likely@secretlab.ca>
>> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
>> Cc: Mark Grosen <mgrosen@ti.com>
>
> Acked-by: Grant Likely <grant.likely@secretlab.ca>

Thanks, applied both patches to remoteproc's for-next.