That patch used to just add a hook to page table flushing but
pulling that string brought out a whole bunch of issues, so it
now does that and more:

 - We now make the RCU batching of page freeing SMP only, as I
believe it was intended initially. We make a few more things compile
to nothing on !CONFIG_SMP

 - Some macros are turned into functions, though that forced me to
out of line a few stuffs due to unsolvable include depenencies,
however it's probably better that way anyway, it's not -that-
critical code path.

 - 32-bit didn't call pte_free_finish() on tlb_flush() which means
that it wouldn't push out the batch to RCU for delayed freeing when
a bunch of page tables have been freed, they would just stay in there
until the batch gets full.

64-bit BookE will use that hook to maintain the virtually linear
page tables or the indirect entries in the TLB when using the
HW loader.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

pr_debug() can now result in code being generated even when DEBUG
is not defined. That's not really desirable in some places.

With CONFIG_DYNAMIC_DEBUG=y:

size before:
   text    data     bss     dec     hex filename
   2036     368       8    2412     96c arch/powerpc/mm/pgtable.o

size after:
   text    data     bss     dec     hex filename
   1677     248       8    1933     78d arch/powerpc/mm/pgtable.o
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

With CONFIG_DEBUG_VM, an assertion is made when changing the protection
flags of a PTE that the PTE is locked. Huge pages use a different pagetable
format and the assertion is bogus and will always trigger with a bug looking
something like

 Unable to handle kernel paging request for data at address 0xf1a00235800006f8
 Faulting instruction address: 0xc000000000034a80
 Oops: Kernel access of bad area, sig: 11 [#1]
 SMP NR_CPUS=32 NUMA Maple
 Modules linked in: dm_snapshot dm_mirror dm_region_hash
  dm_log dm_mod loop evdev ext3 jbd mbcache sg sd_mod ide_pci_generic
  pata_amd ata_generic ipr libata tg3 libphy scsi_mod windfarm_pid
  windfarm_smu_sat windfarm_max6690_sensor windfarm_lm75_sensor
  windfarm_cpufreq_clamp windfarm_core i2c_powermac
 NIP: c000000000034a80 LR: c000000000034b18 CTR: 0000000000000003
 REGS: c000000003037600 TRAP: 0300   Not tainted (2.6.30-rc3-autokern1)
 MSR: 9000000000009032 <EE,ME,IR,DR>  CR: 28002484  XER: 200fffff
 DAR: f1a00235800006f8, DSISR: 0000000040010000
 TASK = c0000002e54cc740[2960] 'map_high_trunca' THREAD: c000000003034000 CPU: 2
 GPR00: 4000000000000000 c000000003037880 c000000000895d30 c0000002e5a2e500
 GPR04: 00000000a0000000 c0000002edc40880 0000005700000393 0000000000000001
 GPR08: f000000011ac0000 01a00235800006e8 00000000000000f5 f1a00235800006e8
 GPR12: 0000000028000484 c0000000008dd780 0000000000001000 0000000000000000
 GPR16: fffffffffffff000 0000000000000000 00000000a0000000 c000000003037a20
 GPR20: c0000002e5f4ece8 0000000000001000 c0000002edc40880 0000000000000000
 GPR24: c0000002e5f4ece8 0000000000000000 00000000a0000000 c0000002e5f4ece8
 GPR28: 0000005700000393 c0000002e5a2e500 00000000a0000000 c000000003037880
 NIP [c000000000034a80] .assert_pte_locked+0xa4/0xd0
 LR [c000000000034b18] .ptep_set_access_flags+0x6c/0xb4
 Call Trace:
 [c000000003037880] [c000000003037990] 0xc000000003037990 (unreliable)
 [c000000003037910] [c000000000034b18] .ptep_set_access_flags+0x6c/0xb4
 [c0000000030379b0] [c00000000014bef8] .hugetlb_cow+0x124/0x674
 [c000000003037b00] [c00000000014c930] .hugetlb_fault+0x4e8/0x6f8
 [c000000003037c00] [c00000000013443c] .handle_mm_fault+0xac/0x828
 [c000000003037cf0] [c0000000000340a8] .do_page_fault+0x39c/0x584
 [c000000003037e30] [c0000000000057b0] handle_page_fault+0x20/0x5c
 Instruction dump:
 7d29582a 7d200074 7800d182 0b000000 3c004000 3960ffff 780007c6 796b00c4
 7d290214 7929a302 1d290068 7d6b4a14 <800b0010> 7c000074 7800d182 0b000000

This patch fixes the problem by not asseting the PTE is locked for VMAs
backed by huge pages.
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Makes code futureproof against the impending change to mm->cpu_vm_mask.

It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch reworks the way we do I and D cache coherency on PowerPC.

The "old" way was split in 3 different parts depending on the processor type:

   - Hash with per-page exec support (64-bit and >= POWER4 only) does it
at hashing time, by preventing exec on unclean pages and cleaning pages
on exec faults.

   - Everything without per-page exec support (32-bit hash, 8xx, and
64-bit < POWER4) does it for all page going to user space in update_mmu_cache().

   - Embedded with per-page exec support does it from do_page_fault() on
exec faults, in a way similar to what the hash code does.

That leads to confusion, and bugs. For example, the method using update_mmu_cache()
is racy on SMP where another processor can see the new PTE and hash it in before
we have cleaned the cache, and then blow trying to execute. This is hard to hit but
I think it has bitten us in the past.

Also, it's inefficient for embedded where we always end up having to do at least
one more page fault.

This reworks the whole thing by moving the cache sync into two main call sites,
though we keep different behaviours depending on the HW capability. The call
sites are set_pte_at() which is now made out of line, and ptep_set_access_flags()
which joins the former in pgtable.c

The base idea for Embedded with per-page exec support, is that we now do the
flush at set_pte_at() time when coming from an exec fault, which allows us
to avoid the double fault problem completely (we can even improve the situation
more by implementing TLB preload in update_mmu_cache() but that's for later).

If for some reason we didn't do it there and we try to execute, we'll hit
the page fault, which will do a minor fault, which will hit ptep_set_access_flags()
to do things like update _PAGE_ACCESSED or _PAGE_DIRTY if needed, we just make
this guys also perform the I/D cache sync for exec faults now. This second path
is the catch all for things that weren't cleaned at set_pte_at() time.

For cpus without per-pag exec support, we always do the sync at set_pte_at(),
thus guaranteeing that when the PTE is visible to other processors, the cache
is clean.

For the 64-bit hash with per-page exec support case, we keep the old mechanism
for now. I'll look into changing it later, once I've reworked a bit how we
use _PAGE_EXEC.

This is also a first step for adding _PAGE_EXEC support for embedded platforms
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Refactor the RCU based pte free code that was used on ppc64 to be used
on all powerpc.

Additionally refactor pte_free() & pte_free_kernel() into common code
between ppc32 & ppc64.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
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 also creates merged versions of do_init_bootmem, paging_init
and mem_init and moves them to arch/powerpc/mm/mem.c.  It gets rid
of the mem_pieces stuff.

I made memory_limit a parameter to lmb_enforce_memory_limit rather
than a global referenced by that function.  This will require some
small changes to ppc64 if we want to continue building ARCH=ppc64
using the merged lmb.c.
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>

Made the number of TLB CAM entries private and converted the board
consumers to use num_tlbcam_entries which is setup at boot time from
configuration registers.  This way the only consumers of the #define
NUM_TLBCAMS are the arrays used to manage the TLB.
Signed-off-by: NKumar Gala <kumar.gala@freescale.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

CONFIG_PTE_64BIT & CONFIG_PHYS_64BIT are not currently consistently used in
the code base.  Fixed up the usage such that CONFIG_PTE_64BIT is used when we
have a 64-bit PTE regardless of physical address width.  CONFIG_PHYS_64BIT is
used if the physical address width is larger than 32-bits, regardless of PTE
size.

These changes required a few sub-arch specific ifdef's to be fixed and the
introduction of a physical address format string.
Signed-off-by: NKumar Gala <kumar.gala@freescale.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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!