[PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Kent Yoder]

acpi_os_map_memory expects its return value to be in the __iomem address
space. Cast it back later when used in a memcpy to avoid the same sparse
warning there.

Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
---
 drivers/char/tpm/tpm_acpi.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
index fe3fa94..36bdcfa 100644
--- a/drivers/char/tpm/tpm_acpi.c
+++ b/drivers/char/tpm/tpm_acpi.c
@@ -49,7 +49,7 @@ int read_log(struct tpm_bios_log *log)
 {
 	struct acpi_tcpa *buff;
 	acpi_status status;
-	struct acpi_table_header *virt;
+	void __iomem *virt;
 	u64 len, start;
 
 	if (log->bios_event_log != NULL) {
@@ -102,7 +102,7 @@ int read_log(struct tpm_bios_log *log)
 		return -EIO;
 	}
 
-	memcpy(log->bios_event_log, virt, len);
+	memcpy(log->bios_event_log, (void *)virt, len);
 
 	acpi_os_unmap_memory(virt, len);
 	return 0;
-- 
1.7.5.4

Re: [PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Dan Carpenter]

On Thu, Aug 30, 2012 at 09:38:41AM -0500, Kent Yoder wrote:
> acpi_os_map_memory expects its return value to be in the __iomem address
> space. Cast it back later when used in a memcpy to avoid the same sparse
> warning there.
> 
> Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

I can't download linux-next right now but I don't think this is the
correct fix.  I don't think you can memcpy() directly from __iomem.
The static checker is warning about a valid bug which should be
addressed instead of just casted away and silenced.

regards,
dan carpenter

Re: [PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Kent Yoder]

On Thu, Aug 30, 2012 at 10:45:56AM -0700, Dan Carpenter wrote:
> On Thu, Aug 30, 2012 at 09:38:41AM -0500, Kent Yoder wrote:
> > acpi_os_map_memory expects its return value to be in the __iomem address
> > space. Cast it back later when used in a memcpy to avoid the same sparse
> > warning there.
> > 
> > Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
> 
> I can't download linux-next right now but I don't think this is the
> correct fix.  I don't think you can memcpy() directly from __iomem.
> The static checker is warning about a valid bug which should be
> addressed instead of just casted away and silenced.

  I took a look at other uses of the return from acpi_os_map_memory(),
such as acpi_tb_parse_fadt(), which passes the returned pointer to
acpi_tb_create_local_fadt(), which uses ACPI_MEMCPY on it, which is just
memcpy.  This code lives in drivers/acpi.

Kent

> 
> regards,
> dan carpenter
> 
> 

Re: [PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Dan Carpenter]

On Thu, Aug 30, 2012 at 02:21:55PM -0500, Kent Yoder wrote:
> On Thu, Aug 30, 2012 at 10:45:56AM -0700, Dan Carpenter wrote:
> > On Thu, Aug 30, 2012 at 09:38:41AM -0500, Kent Yoder wrote:
> > > acpi_os_map_memory expects its return value to be in the __iomem address
> > > space. Cast it back later when used in a memcpy to avoid the same sparse
> > > warning there.
> > > 
> > > Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
> > 
> > I can't download linux-next right now but I don't think this is the
> > correct fix.  I don't think you can memcpy() directly from __iomem.
> > The static checker is warning about a valid bug which should be
> > addressed instead of just casted away and silenced.
> 
>   I took a look at other uses of the return from acpi_os_map_memory(),
> such as acpi_tb_parse_fadt(), which passes the returned pointer to
> acpi_tb_create_local_fadt(), which uses ACPI_MEMCPY on it, which is just
> memcpy.  This code lives in drivers/acpi.
> 

Sparse finds that bug as well.  ;)

drivers/acpi/acpica/tbfadt.c:247:15: warning: incorrect type in assignment (different address spaces)
drivers/acpi/acpica/tbfadt.c:247:15:    expected struct acpi_table_header *table
drivers/acpi/acpica/tbfadt.c:247:15:    got void [noderef] <asn:2>*
drivers/acpi/acpica/tbfadt.c:266:30: warning: incorrect type in argument 1 (different address spaces)
drivers/acpi/acpica/tbfadt.c:266:30:    expected void [noderef] <asn:2>*logical_address
drivers/acpi/acpica/tbfadt.c:266:30:    got struct acpi_table_header *table

It should be memcpy_fromio() probably.

regards,
dan carpenter

Re: [PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Kent Yoder]

On Sun, Sep 02, 2012 at 09:30:30AM -0700, Dan Carpenter wrote:
> Sparse finds that bug as well.  ;)
> 
> drivers/acpi/acpica/tbfadt.c:247:15: warning: incorrect type in assignment (different address spaces)
> drivers/acpi/acpica/tbfadt.c:247:15:    expected struct acpi_table_header *table
> drivers/acpi/acpica/tbfadt.c:247:15:    got void [noderef] <asn:2>*
> drivers/acpi/acpica/tbfadt.c:266:30: warning: incorrect type in argument 1 (different address spaces)
> drivers/acpi/acpica/tbfadt.c:266:30:    expected void [noderef] <asn:2>*logical_address
> drivers/acpi/acpica/tbfadt.c:266:30:    got struct acpi_table_header *table
> 
> It should be memcpy_fromio() probably.

  Thanks Dan, that's clearly better. James, I'll resubmit this one
today.

Thanks,
Kent

[PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[Kent Yoder]

acpi_os_map_memory expects its return value to be in the __iomem address
space. Tag the variable we're using as such and use memcpy_fromio to
avoid further sparse warnings.

Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
---
 drivers/char/tpm/tpm_acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
index fe3fa94..56051d0 100644
--- a/drivers/char/tpm/tpm_acpi.c
+++ b/drivers/char/tpm/tpm_acpi.c
@@ -49,7 +49,7 @@ int read_log(struct tpm_bios_log *log)
 {
 	struct acpi_tcpa *buff;
 	acpi_status status;
-	struct acpi_table_header *virt;
+	void __iomem *virt;
 	u64 len, start;
 
 	if (log->bios_event_log != NULL) {
@@ -102,7 +102,7 @@ int read_log(struct tpm_bios_log *log)
 		return -EIO;
 	}
 
-	memcpy(log->bios_event_log, virt, len);
+	memcpy_fromio(log->bios_event_log, virt, len);
 
 	acpi_os_unmap_memory(virt, len);
 	return 0;
-- 
1.7.11.4

Re: [PATCH] tpm: fix tpm_acpi sparse warning on different address spaces

[James Morris]

On Tue, 4 Sep 2012, Kent Yoder wrote:

> acpi_os_map_memory expects its return value to be in the __iomem address
> space. Tag the variable we're using as such and use memcpy_fromio to
> avoid further sparse warnings.
> 
> Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>

Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git next


-- 
James Morris
<jmorris@namei.org>