Hi,
There is an API issue surrounding the following structure in
linux/include/linux/if.h, which has been in the kernel since 2.0
days:
struct ifmap
{
unsigned long mem_start;
unsigned long mem_end;
unsigned short base_addr;
unsigned char irq;
unsigned char dma;
unsigned char port;
/* 3 bytes spare */
};
The problem area is base_addr. It appears to assume that you always have
a maximum of a 64K IO space, which is obviously broken for 64-bit
architectures and other machines which have more than a 64K IO space.
What's even more strange is that "base_addr" is initialised from the
base_addr element of struct net_device, which is declared as an
unsigned long (it was an unsigned short back in the older days of Linux
though):
struct net_device
{
...
unsigned long base_addr; /* device I/O address */
Obviously on an architecture which does make use of the full 32-bits
or 64-bits of IO address range, things are not going to work as expected.
It would be desirable to fix this, especially as its certainly far from
obsolete - ifconfig has recently had support added for setting the above
information, and there is some limited support in the kernel for accepting
this information.
I propose that we need to obsolete the current SIOC[SG]IFMAP ioctls and
introduce new ones which supply a 32-bit version of the base address
(and explicitly pad the structure, rather than just commenting that
there are 3 bytes spare).
Comments anyone?
_____
|_____| ------------------------------------------------- ---+---+-
| | Russell King rmk@arm.linux.org.uk --- ---
| | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / |
| +-+-+ --- -+-
/ | THE developer of ARM Linux |+| /|\
/ | | | --- |
+-+-+ ------------------------------------------------- /\\\ |
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