Currently kernel images are limited to 8MB in size, and this causes
problems especially when enabling features that take up a lot of
kernel image space such as lockdep.
The code now will align the kernel image size up to 4MB and map that
many locked TLB entries. So, the only practical limitation is the
number of available locked TLB entries which is 16 on Cheetah and 64
on pre-Cheetah sparc64 cpus. Niagara cpus don't actually have hw
locked TLB entry support. Rather, the hypervisor transparently
provides support for "locked" TLB entries since it runs with physical
addressing and does the initial TLB miss processing.
Fully utilizing this change requires some help from SILO, a patch for
which will be submitted to the maintainer. Essentially, SILO will
only currently map up to 8MB for the kernel image and that needs to be
increased.
Note that neither this patch nor the SILO bits will help with network
booting. The openfirmware code will only map up to a certain amount
of kernel image during a network boot and there isn't much we can to
about that other than to implemented a layered network booting
facility. Solaris has this, and calls it "wanboot" and we may
implement something similar at some point.
Signed-off-by: David S. Miller <davem@davemloft.net>
Check the cpu type in the OBP device tree before committing to
using the optimized Niagara memcpy and memset implementation.
If we don't recognize the cpu type, use a completely generic
version.
Signed-off-by: David S. Miller <davem@davemloft.net>
In particular, avoid membar instructions in the delay
slot of a jmpl instruction.
UltraSPARC-I, II, IIi, and IIe have a bug, documented in
the UltraSPARC-IIi User's Manual, Appendix K, Erratum 51
The long and short of it is that if the IMU unit misses
on a branch or jmpl, and there is a store buffer synchronizing
membar in the delay slot, the chip can stop fetching instructions.
If interrupts are enabled or some other trap is enabled, the
chip will unwedge itself, but performance will suffer.
We already had a workaround for this bug in a few spots, but
it's better to have the entire tree sanitized for this rule.
Signed-off-by: David S. Miller <davem@davemloft.net>
Older UltraSPARC-III chips have a P-Cache bug that makes us disable it
by default at boot time.
However, this does hurt performance substantially, particularly with
memcpy(), and the bug is _incredibly_ obscure. I have never seen it
triggered in practice, ever.
So provide a "-P" boot option that forces the P-Cache on. It taints
the kernel, so if it does trigger and cause some data corruption or
OOPS, we will find out in the logs that this option was on when it
happened.
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
David S. Miller