Messages in this thread | | | Date | Tue, 21 Apr 2015 16:13:01 +0200 | From | Stefan Richter <> | Subject | Re: [PATCH 1/2] firewire: firewire is a big-endian bus |
| |
On Apr 20 Joe Perches wrote: > On Tue, 2015-04-21 at 02:36 +0200, Laurent Vivier wrote: > > So, dump config_rom data as big-endian values. > > > > The value given by /sys/bus/firewire/devices/fw0 were correctly > > given on a big-endian host (like powermac) not on a little-endian host > > (like PC), for instance: > [] > > diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c > [] > > @@ -399,14 +399,14 @@ static ssize_t config_rom_show(struct device *dev, > > struct device_attribute *attr, char *buf) > > { > > struct fw_device *device = fw_device(dev); > > - size_t length; > > + size_t i; > > > > down_read(&fw_device_rwsem); > > - length = device->config_rom_length * 4; > > - memcpy(buf, device->config_rom, length); > > + for (i = 0; i < device->config_rom_length; i++) > > + ((u32 *)buf)[i] = be32_to_cpu(device->config_rom[i]); > > Is buf guaranteed to be appropriately aligned on a u32?
Good catch. Though as far as I know, the buffer is page-sized and thereby certainly page-aligned. This could be looked up in the sysfs core code.
BTW, theoretically speaking it should be cpu_to_be32() here, and the buffer pointer should be annotated as a big endian pointer. (But as I noted in the previous reply, the patch will not be applied either way.) -- Stefan Richter -=====-===== -=-- =-=-= http://arcgraph.de/sr/
| |