The registers that describe size supported by TLB are different on MMU
v2 as well as we support power of two page sizes.  For now we continue
to assume that FSL variable size array supports all page sizes up to the
maximum one reported in TLB1PS.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Currently, it does a cntlzd on the size and then subtracts it from
21.... this doesn't take into account the varying size of a "long".
Just use __ilog instead (and subtract the 10 we have to subtract
to get to the tsize encoding).

Also correct the comment about page sizes supported.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

On FSL Book-E devices we support multiple large TLB sizes and so we can
get into situations in which the initial 1G TLB size is too big and
we're asked for a size that is not mappable by a single entry (like
512M).  The single entry is important because when we bring up secondary
cores they need to ensure any data structure they need to access (eg
PACA or stack) is always mapped.

So we really need to determine what size will actually be mapped by the
first TLB entry to ensure we limit early memory references to that
region.  We refactor the map_mem_in_cams() code to provider a helper
function that we can utilize to determine the size of the first TLB
entry while taking into account size and alignment constraints.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

On Freescale parts typically have TLB array for large mappings that we can
bolt the linear mapping into.  We utilize the code that already exists
on PPC32 on the 64-bit side to setup the linear mapping to be cover by
bolted TLB entries.  We utilize a quarter of the variable size TLB array
for this purpose.

Additionally, we limit the amount of memory to what we can cover via
bolted entries so we don't get secondary faults in the TLB miss
handlers.  We should fix this limitation in the future.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

There exists a four line chunk of code, which when configured for
64 bit address space, can incorrectly set certain page flags during
the TLB creation.  It turns out that this is code which isn't used,
but might still serve a purpose.  Since it isn't obvious why it exists
or why it causes problems, the below description covers both in detail.

For powerpc bootstrap, the physical memory (at most 768M), is mapped
into the kernel space via the following path:

MMU_init()
    |
    + adjust_total_lowmem()
            |
            + map_mem_in_cams()
                    |
                    + settlbcam(i, virt, phys, cam_sz, PAGE_KERNEL_X, 0);

On settlbcam(), the kernel will create TLB entries according to the flag,
PAGE_KERNEL_X.

settlbcam()
{
        ...
        TLBCAM[index].MAS1 = MAS1_VALID
                        | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
                                ^
			These entries cannot be invalidated by the
			kernel since MAS1_IPROT is set on TLB property.
        ...
        if (flags & _PAGE_USER) {
           TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
           TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
        }

For classic BookE (flags & _PAGE_USER) is 'zero' so it's fine.
But on boards like the the Freescale P4080, we want to support 36-bit
physical address on it. So the following options may be set:

CONFIG_FSL_BOOKE=y
CONFIG_PTE_64BIT=y
CONFIG_PHYS_64BIT=y

As a result, boards like the P4080 will introduce PTE format as Book3E.
As per the file: arch/powerpc/include/asm/pgtable-ppc32.h

  * #elif defined(CONFIG_FSL_BOOKE) && defined(CONFIG_PTE_64BIT)
  * #include <asm/pte-book3e.h>

So PAGE_KERNEL_X is __pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX) and the
book3E version of _PAGE_KERNEL_RWX is defined with:

  (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY | _PAGE_BAP_SX)

Note the _PAGE_BAP_SR, which is also defined in the book3E _PAGE_USER:

  #define _PAGE_USER        (_PAGE_BAP_UR | _PAGE_BAP_SR) /* Can be read */

So the possibility exists to wrongly assign the user MAS3_U<RWX> bits
to kernel (PAGE_KERNEL_X) address space via the following code fragment:

        if (flags & _PAGE_USER) {
           TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
           TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
        }

Here is a dump of the TLB info from Simics with the above code present:
------
L2 TLB1
                                            GT                   SSS UUU V I
 Row  Logical           Physical            SS TLPID  TID  WIMGE XWR XWR F P   V
----- ----------------- ------------------- -- ----- ----- ----- --- --- - -   -
  0   c0000000-cfffffff 000000000-00fffffff 00     0     0   M   XWR XWR 0 1   1
  1   d0000000-dfffffff 010000000-01fffffff 00     0     0   M   XWR XWR 0 1   1
  2   e0000000-efffffff 020000000-02fffffff 00     0     0   M   XWR XWR 0 1   1

Actually this conditional code was used for two legacy functions:

  1: support KGDB to set break point.
     KGDB already dropped this; now uses its core write to set break point.

  2: io_block_mapping() to create TLB in segmentation size (not PAGE_SIZE)
     for device IO space.
     This use case is also removed from the latest PowerPC kernel.

However, there may still be a use case for it in the future, like
large user pages, so we can't remove it entirely.  As an alternative,
we match on all bits of _PAGE_USER instead of just any bits, so the
case where just _PAGE_BAP_SR is set can't sneak through.

With this done, the TLB appears without U having XWR as below:

-------
L2 TLB1
                                            GT                   SSS UUU V I
 Row  Logical           Physical            SS TLPID  TID  WIMGE XWR XWR F P   V
----- ----------------- ------------------- -- ----- ----- ----- --- --- - -   -
  0   c0000000-cfffffff 000000000-00fffffff 00     0     0   M   XWR     0 1   1
  1   d0000000-dfffffff 010000000-01fffffff 00     0     0   M   XWR     0 1   1
  2   e0000000-efffffff 020000000-02fffffff 00     0     0   M   XWR     0 1   1
Signed-off-by: NTiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The RMA (RMO is a misnomer) is a concept specific to ppc64 (in fact
server ppc64 though I hijack it on embedded ppc64 for similar purposes)
and represents the area of memory that can be accessed in real mode
(aka with MMU off), or on embedded, from the exception vectors (which
is bolted in the TLB) which pretty much boils down to the same thing.

We take that out of the generic MEMBLOCK data structure and move it into
arch/powerpc where it belongs, renaming it to "RMA" while at it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This introduce memblock.current_limit which is used to limit allocations
from memblock_alloc() or memblock_alloc_base(..., MEMBLOCK_ALLOC_ACCESSIBLE).

The old MEMBLOCK_ALLOC_ANYWHERE changes value from 0 to ~(u64)0 and can still
be used with memblock_alloc_base() to allocate really anywhere.

It is -no-longer- cropped to MEMBLOCK_REAL_LIMIT which disappears.

Note to archs: I'm leaving the default limit to MEMBLOCK_ALLOC_ANYWHERE. I
strongly recommend that you ensure that you set an appropriate limit
during boot in order to guarantee that an memblock_alloc() at any time
results in something that is accessible with a simple __va().

The reason is that a subsequent patch will introduce the ability for
the array to resize itself by reallocating itself. The MEMBLOCK core will
honor the current limit when performing those allocations.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

There are no BATS on BookE - we have the TLBCAM instead.  Also correct
the page size information to included extended sizes.  We don't actually allow
a 4G page size to be used, so comment on that as well.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When we build with ftrace enabled its possible that loadcam_entry would
have used the stack pointer (even though the code doesn't need it).  We
call loadcam_entry in __secondary_start before the stack is setup.  To
ensure that loadcam_entry doesn't use the stack pointer the easiest
solution is to just have it in asm code.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

When we build with ftrace enabled its possible that loadcam_entry would
have used the stack pointer (even though the code doesn't need it).  We
call loadcam_entry in __secondary_start before the stack is setup.  To
ensure that loadcam_entry doesn't use the stack pointer the easiest
solution is to just have it in asm code.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The bypassing of this test is a leftover from 2.4 vintage
kernels, and is no longer appropriate, or even used by KGDB.
Currently KGDB uses probe_kernel_write() for all access to
memory via the KGDB core, so it can simply be deleted.

This fixes CVE-2010-1446.

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: NWufei <fei.wu@windriver.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

The code was looking for this in cpu_features, not mmu_features.  Fix this.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Today's linux-next build (powerpc ppc44x_defconfig) failed like this:

arch/powerpc/mm/pgtable_32.c: In function 'mapin_ram':
arch/powerpc/mm/pgtable_32.c:318: error: too many arguments to function 'mmu_mapin_ram'

Casued by commit de32400d ("wii: use both
mem1 and mem2 as ram").
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Re-write the code so its more standalone and fixed some issues:
* Bump'd # of CAM entries to 64 to support e500mc
* Make the code handle MAS7 properly
* Use pr_cont instead of creating a string as we go
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

cam[tlbcam_index] is checked before tlbcam_index < ARRAY_SIZE(cam)
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch tweaks the way some PTE bit combinations are defined, in such a
way that the 32 and 64-bit variant become almost identical and that will
make it easier to bring in a new common pte-* file for the new variant
of the Book3-E support.

The combination of bits defining access to kernel pages are now clearly
separated from the combination used by userspace and the core VM. The
resulting generated code should remain identical unless I made a mistake.

Note: While at it, I removed a non-sensical statement related to CONFIG_KGDB
in ppc_mmu_32.c which could cause kernel mappings to be user accessible when
that option is enabled. Probably something that bitrot.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/fsl_booke_mmu.c: In function 'adjust_total_lowmem':
arch/powerpc/mm/fsl_booke_mmu.c:221: warning: format '%ld' expects type 'long int', but argument 3 has type 'phys_addr_t'
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The Power ISA 2.06 added power of two page sizes to the embedded MMU
architecture.  Its done it such a way to be code compatiable with the
existing HW.  Made the minor code changes to support both power of two
and power of four page sizes.  Also added some new MAS bits and macros
that are defined as part of the 2.06 ISA.  Renamed some things to use
the 'Book-3e' concept to convey the new MMU that is based on the
Freescale Book-E MMU programming model.

Note, its still invalid to try and use a page size that isn't supported
by cpu.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Fixed v_mapped_by_tlbcam() and p_mapped_by_tlbcam() to use phys_addr_t
instead of unsigned long.  In 36-bit physical mode we really need these
functions to deal with phys_addr_t when trying to match a physical
address or when returning one.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

On booke processors, the code that maps low memory only uses up to three
CAM entries, even though there are sixteen and nothing else uses them.

Make this number configurable in the advanced options menu along with max
low memory size.  If one wants 1 GB of lowmem, then it's typically
necessary to have four CAM entries.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The code that maps kernel low memory would only use page sizes up to 256
MB.  On E500v2 pages up to 4 GB are supported.

However, a page must be aligned to a multiple of the page's size.  I.e.
256 MB pages must aligned to a 256 MB boundary.  This was enforced by a
requirement that the physical and virtual addresses of the start of lowmem
be aligned to 256 MB.  Clearly requiring 1GB or 4GB alignment to allow
pages of that size isn't acceptable.

To solve this, I simply have adjust_total_lowmem() take alignment into
account when it decides what size pages to use.  Give it PAGE_OFFSET =
0x7000_0000, PHYSICAL_START = 0x3000_0000, and 2GB of RAM, and it will map
pages like this:
PA 0x3000_0000 VA 0x7000_0000 Size 256 MB
PA 0x4000_0000 VA 0x8000_0000 Size 1 GB
PA 0x8000_0000 VA 0xC000_0000 Size 256 MB
PA 0x9000_0000 VA 0xD000_0000 Size 256 MB
PA 0xA000_0000 VA 0xE000_0000 Size 256 MB

Because the lowmem mapping code now takes alignment into account,
PHYSICAL_ALIGN can be lowered from 256 MB to 64 MB.  Even lower might be
possible.  The lowmem code will work down to 4 kB but it's possible some of
the boot code will fail before then.  Poor alignment will force small pages
to be used, which combined with the limited number of TLB1 pages available,
will result in very little memory getting mapped.  So alignments less than
64 MB probably aren't very useful anyway.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The code to map lowmem uses three CAM aka TLB[1] entries to cover it.  The
size of each is stored in three globals named __cam0, __cam1, and __cam2.
All the code that uses them is duplicated three times for each of the three
variables.

We have these things called arrays and loops....

Once converted to use an array, it will be easier to make the number of
CAMs configurable.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

This is a global variable defined in fsl_booke_mmu.c with a value that gets
initialized in assembly code in head_fsl_booke.S.

It's never used.

If some code ever does want to know the number of entries in TLB1, then
"numcams = mfspr(SPRN_TLB1CFG) & 0xfff", is a whole lot simpler than a
global initialized during kernel boot from assembly.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Some assembly code in head_fsl_booke.S hard-coded the size of struct tlbcam
to 20 when it indexed the TLBCAM table.  Anyone changing the size of struct
tlbcam would not know to expect that.

The kernel already has a system to get the size of C structures into
assembly language files, asm-offsets, so let's use it.

The definition of the struct gets moved to a header, so that asm-offsets.c
can include it.
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

This fixes a build warning when PHYS_64BIT is enabled, and removes an
unnecessary cast to phys_addr_t (the variable being cast is already
a phys_addr_t)
Signed-off-by: NBecky Bruce <becky.bruce@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Added support to allow an 85xx kernel to be run from a non-zero physical
address (useful for cooperative asymmetric multiprocessing situations and
kdump).  The support can be configured at compile time by setting
CONFIG_PAGE_OFFSET, CONFIG_KERNEL_START, and CONFIG_PHYSICAL_START as
desired.

Alternatively, the kernel build can set CONFIG_RELOCATABLE.  Setting this
config option causes the kernel to determine at runtime the physical
addresses of CONFIG_PAGE_OFFSET and CONFIG_KERNEL_START.  If
CONFIG_RELOCATABLE is set, then CONFIG_PHYSICAL_START has no meaning.
However, CONFIG_PHYSICAL_START will always be used to set the LOAD program
header physical address field in the resulting ELF image.

Currently we are limited to running at a physical address that is a
multiple of 256M.  This is due to how we map TLBs to cover
lowmem.  This should be fixed to allow 64M or maybe even 16M alignment
in the future.  It is considered an error to try and run a kernel at a
non-aligned physical address.

All the magic for this support is accomplished by proper initialization
of the kernel memory subsystem and use of ARCH_PFN_OFFSET.

The use of ARCH_PFN_OFFSET only affects normal memory and not IO mappings.
ioremap uses map_page and isn't affected by ARCH_PFN_OFFSET.

/dev/mem continues to allow access to any physical address in the system
regardless of how CONFIG_PHYSICAL_START is set.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

We always use __initial_memory_limit as an address so rename it
to be clear.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

* Determine the RPN we are running the kernel at runtime rather
  than using compile time constant for initial TLB

* Cleanup adjust_total_lowmem() to respect memstart_addr and
  be a bit more clear on variables that are sizes vs addresses.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

A number of users of PPC_MEMSTART (40x, ppc_mmu_32) can just always
use 0 as we don't support booting these kernels at non-zero physical
addresses since their exception vectors must be at 0 (or 0xfffx_xxxx).

For the sub-arches that support relocatable interrupt vectors
(book-e), it's reasonable to have memory start at a non-zero physical
address.  For those cases use the variable memstart_addr instead of
the #define PPC_MEMSTART since the only uses of PPC_MEMSTART are for
initialization and in the future we can set memstart_addr at runtime
to have a relocatable kernel.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The e500 MMU init code previously assumed KERNELBASE always equaled
PAGE_OFFSET and PHYSICAL_START was 0.  This is useful for kdump
support as well as asymetric multicore.

For the initial kdump support the secondary kernel will run at 32M
but need access to all of memory so we bump the initial TLB up to
64M.  This also matches with the forth coming ePAPR spec.
Signed-off-by: NDale Farnsworth <dale@farnsworth.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The CONFIG_FSL_BOOKE mmu setup code fails when CONFIG_HIGHMEM=y
and the 3 fixed TLB entries cannot exactly map the lowmem size.
Each TLB entry can map 4MB, 16MB, 64MB or 256MB, so the failure
is observed when the kernel lowmem size is not equal to the
sum of up to 3 of those values.

Normally, memory is sized in nice numbers, but I observed this
problem while testing a crash dump kernel.  The failure can
also be observed by artificially reducing the kernel's main
memory via the mem= kernel command line parameter.

This commit fixes the problem by setting __initial_memory_limit
in adjust_total_lowmem().
Signed-off-by: NDale Farnsworth <dale@farnsworth.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

APUS (the Amiga Power-Up System) is not supported under arch/powerpc
and it's unlikely it ever will be.  Therefore, this patch removes the
fragments of APUS support code from arch/powerpc which have been
copied from arch/ppc.

A few APUS references are left in asm-powerpc in .h files which are
still used from arch/ppc.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
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>

Changed jobs and the Freescale address is no longer valid.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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>

Continue the Good Fight:  Limit bootmem.h include creep.
Signed-off-by: NJon Loeliger <jdl@freescale.com>
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>

The e200 core is a Book-E core (similar to e500) that has a unified L1 cache
and is not cache coherent on the bus.  The e200 core also adds a separate
exception level for debug exceptions.  Part of this patch helps to cleanup a
few cases that are true for all Freescale Book-E parts, not just e500.
Signed-off-by: NKim Phillips <kim.phillips@freescale.com>
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>

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>

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!