[linuxsh-dev] Drop-In tree updates

[Jeremy S. <js...@mv...>]

Hi folks,

Trying to keep the drop-in trees easy to drop in, over the last several
days I've updated the 2.4 branch to 2.4.16 and the 2.5 branch to 2.5.0;
before modifying the 2.4 branch I retagged it linux-2.4.13-pre2, so you
can pull the old one with that tag.

However: I only tested minimal SH3/SH4 Solution Engine platforms, so
other things may have broken (e.g. Robert Love already submitted a fix
for the gdrom, which apparently didn't even compile.)

In a couple cases, diffs to the SH tree conflicted with generic kernel
changes and they may not be correct now; those more familiar with these
specific portions of code may want to take a look at them...

drivers/net/8139too.c:
  Most SH changes (buffer size and DMA for Dreamcast) carried forward,
  except for the last one in rtl8139_start_xmit(), where USE_NO_DMAMAP
  forced an skb_copy_and_csum_dev() call.  The copy is now done all the
  time, so there was nowhere to put that check; I assume that's ok?
  (Come to think of it, that means USE_NO_DMAMAP could be removed.)

mm/memory.c:
  There were two places where the SH code ifdef'd out cache flush calls
  for performance, noting in comments that a VIPT cache doesn't require
  them.  The second of these was in do_wp_page(), and the code changed
  enough that I chose NOT to ifdef out that flush call, since I wasn't
  sure if the conditions that made it unnecessary still applied.

The other places where SH tweaks common code is a few insertions of
cache flush calls; include/linux/highmem.h:memclear_highpage_flush() and
kernel/ptrace.c:access_one_page() both add flush_dcache_page(page) right
before flush_page_to_ram(page).  And drivers/block/rd.c:initrd_read()
adds flush_cache_all() right after a copy_to_user() call.  I left all
these alone, assuming they're still necessary (cache aliasing issue?)
but Niibe may want them removed if they're no longer necessary?

--Jeremy Siegel