Commit Graph

7 Commits

Author SHA1 Message Date
Joel Stanley
63aecfb20a powerpc/powernv: Check sysparam size before creation
The size of the sysparam sysfs files is determined from the device tree
at boot. However the buffer is hard coded to 64 bytes. If we encounter a
parameter that is larger than 64, or miss-parse the device tree, the
buffer will overflow when reading or writing to the parameter.

Check it at discovery time, and if the parameter is too large, do not
create a sysfs entry for it.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:08:49 +10:00
Joel Stanley
16003d235b powerpc/powernv: Fix typos in sysparam code
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:08:49 +10:00
Joel Stanley
85390378f0 powerpc/powernv: Check sysfs size before copying
The sysparam code currently uses the userspace supplied number of
bytes when memcpy()ing in to a local 64-byte buffer.

Limit the maximum number of bytes by the size of the buffer.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:08:48 +10:00
Joel Stanley
b8569d2304 powerpc/powernv: Use ssize_t for sysparam return values
The OPAL calls are returning int64_t values, which the sysparam code
stores in an int, and the sysfs callback returns ssize_t. Make code a
easier to read by consistently using ssize_t.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:08:48 +10:00
Joel Stanley
ba9a32b176 powerpc/powernv: Fix sysparam sysfs error handling
When a sysparam query in OPAL returned a negative value (error code),
sysfs would spew out a decent chunk of memory; almost 64K more than
expected. This was traced to a sign/unsigned mix up in the OPAL sysparam
sysfs code at sys_param_show.

The return value of sys_param_show is a ssize_t, calculated using

  return ret ? ret : attr->param_size;

Alan Modra explains:

  "attr->param_size" is an unsigned int, "ret" an int, so the overall
  expression has type unsigned int.  Result is that ret is cast to
  unsigned int before being cast to ssize_t.

Instead of using the ternary operator, set ret to the param_size if an
error is not detected. The same bug exists in the sysfs write callback;
this patch fixes it in the same way.

A note on debugging this next time: on my system gcc will warn about
this if compiled with -Wsign-compare, which is not enabled by -Wall,
only -Wextra.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-28 13:08:47 +10:00
Anton Blanchard
bb4398e1de powerpc/powernv: Fix endian issues with OPAL async code
OPAL defines opal_msg as a big endian struct so we have to
byte swap it on little endian builds.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-07 10:34:27 +10:00
Neelesh Gupta
4029cd6654 powerpc/powernv: Enable reading and updating of system parameters
This patch enables reading and updating of system parameters through
OPAL call.

Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-03-24 09:47:30 +11:00