hash_page_sync() takes and releases the low level mmu hash
lock in order to sync with other processors disposing of page
tables.  Because that lock can be needed to service hash misses
triggered by interrupt handlers, taking it must be done with
interrupts off.  However, hash_page_sync() appears to be called
with interrupts enabled, thus causing occasional deadlocks.

We fix it by making sure hash_page_sync() masks interrupts while
holding the lock.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

We get the following warnings in various ARCH=powerpc builds:

WARNING: "ee_restarts" [arch/powerpc/kernel/built-in] is COMMON symbol
WARNING: "fee_restarts" [arch/powerpc/kernel/built-in] is COMMON symbol
WARNING: "htab_hash_searches" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "next_slot" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "mmu_hash_lock" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "primary_pteg_full" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "global_dbcr0" [arch/powerpc/kernel/built-in] is COMMON symbol

Switch to moving local symbols (except mmu_hash_lock which is global) and
space directive instead.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

On hash table based 32 bits powerpc's, the hash management code runs with
a big spinlock. It's thus important that it never causes itself a hash
fault. That code is generally safe (it does memory accesses in real mode
among other things) with the exception of the actual access to the code
itself. That is, the kernel text needs to be accessible without taking
a hash miss exceptions.

This is currently guaranteed by having a BAT register mapping part of the
linear mapping permanently, which includes the kernel text. But this is
not true if using the "nobats" kernel command line option (which can be
useful for debugging) and will not be true when using DEBUG_PAGEALLOC
implemented in a subsequent patch.

This patch fixes this by pre-faulting in the hash table pages that hit
the kernel text, and making sure we never evict such a page under hash
pressure.
Signed-off-by: NBenjamin Herrenchmidt <benh@kernel.crashing.org>

 arch/powerpc/mm/hash_low_32.S |   22 ++++++++++++++++++++--
 arch/powerpc/mm/mem.c         |    3 ---
 arch/powerpc/mm/mmu_decl.h    |    4 ++++
 arch/powerpc/mm/pgtable_32.c  |   11 +++++++----
 4 files changed, 31 insertions(+), 9 deletions(-)
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Remove some stale POWER3/POWER4/970 on 32bit kernel support.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This patch removes all self references and fixes references to files
in the now defunct arch/ppc64 tree.  I think this accomplises
everything wanted, though there might be a few references I missed.
Signed-off-by: NJon Mason <jdmason@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Now that the register names and bit definitions are all in reg.h,
use that instead of processor.h in assembly code in a few places.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This doesn't change any code, just renames things so we consistently
have foo_32.c and foo_64.c where we have separate 32- and 64-bit
versions.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This creates the directory structure under arch/powerpc and a bunch
of Kconfig files.  It does a first-cut merge of arch/powerpc/mm,
arch/powerpc/lib and arch/powerpc/platforms/powermac.  This is enough
to build a 32-bit powermac kernel with ARCH=powerpc.

For now we are getting some unmerged files from arch/ppc/kernel and
arch/ppc/syslib, or arch/ppc64/kernel.  This makes some minor changes
to files in those directories and files outside arch/powerpc.

The boot directory is still not merged.  That's going to be interesting.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Delete obsoleted parts form arch makefiles and rename to asm-offsets.h
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

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!