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Switch to using the Power ISA defined PTE format when we have a 64-bit
PTE. This makes the code handling between fsl-booke and book3e-64
similiar for TLB faults.
Additionally this lets use take advantage of the page size encodings and
full permissions that the HW PTE defines.
Also defined _PMD_PRESENT, _PMD_PRESENT_MASK, and _PMD_BAD since the
32-bit ppc arch code expects them.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This is an attempt at cleaning up a bit the way we handle execute
permission on powerpc. _PAGE_HWEXEC is gone, _PAGE_EXEC is now only
defined by CPUs that can do something with it, and the myriad of
#ifdef's in the I$/D$ coherency code is reduced to 2 cases that
hopefully should cover everything.
The logic on BookE is a little bit different than what it was though
not by much. Since now, _PAGE_EXEC will be set by the generic code
for executable pages, we need to filter out if they are unclean and
recover it. However, I don't expect the code to be more bloated than
it already was in that area due to that change.
I could boast that this brings proper enforcing of per-page execute
permissions to all BookE and 40x but in fact, we've had that now for
some time as a side effect of my previous rework in that area (and
I didn't even know it :-) We would only enable execute permission if
the page was cache clean and we would only cache clean it if we took
and exec fault. Since we now enforce that the later only work if
VM_EXEC is part of the VMA flags, we de-fact already enforce per-page
execute permissions... Unless I missed something
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The implementation we just revived has issues, such as using a
Kconfig-defined virtual address area in kernel space that nothing
actually carves out (and thus will overlap whatever is there),
or having some dependencies on being self contained in a single
PTE page which adds unnecessary constraints on the kernel virtual
address space.
This fixes it by using more classic PTE accessors and automatically
locating the area for consistent memory, carving an appropriate hole
in the kernel virtual address space, leaving only the size of that
area as a Kconfig option. It also brings some dma-mask related fixes
from the ARM implementation which was almost identical initially but
grew its own fixes.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Make FIXADDR_TOP a compile time constant and cleanup a
couple of definitions relative to the layout of the kernel
address space on ppc32. We also print out that layout at
boot time for debugging purposes.
This is a pre-requisite for properly fixing non-coherent
DMA allocactions.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Now that they are almost identical, we can merge some of the definitions
related to the PTE format into common files.
This creates a new pte-common.h which is included by both 32 and 64-bit
right after the CPU specific pte-*.h file, and which defines some
bits to "default" values if they haven't been defined already, and
then provides a generic definition of most of the bit combinations
based on these and exposed to the rest of the kernel.
I also moved to the common pgtable.h most of the "small" accessors to the
PTE bits and modification helpers (pte_mk*). The actual accessors remain
in their separate files.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This updates the 32-bit headers to use the same definitions for the RPN
shift inside the PTE as 64-bit, and thus updates _PAGE_CHG_MASK to
become identical.
This does introduce a runtime visible difference, which is that now,
_PAGE_HASHPTE will be part of _PAGE_CHG_MASK and thus preserved. However
this should have no practical effect as it should have been preserved in
the first place and we got away with not having it there due to our
PTE access functions preserving it anyway.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch moves the definition of the PTE format for each MMU type
to separate files instead of all in one file. This improves overall
maintainability and will make it easier to add new types.
On 64-bit, additionally, I've separated the headers relative to the
format of the page table tree (3 vs. 4 levels for 64K vs 4K pages)
from the headers specific to the PTE format for hash based processors,
this will make it easier to add support for Book3 "E" 64-bit
implementations.
There are still some type-related ifdef's in the generic headers,
we might remove them in the long run, but this patch shouldn't result
in any code change, -hopefully- just definitions being moved around.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Manual merge of:
arch/powerpc/include/asm/pgtable-ppc32.h
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Fix _PAGE_CHG_MASK so that pte_modify() does not affect the _PAGE_SPECIAL bit.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Currently, we never set _PAGE_COHERENT in the PTEs, we just OR it in
in the hash code based on some CPU feature bit. We also manipulate
_PAGE_NO_CACHE and _PAGE_GUARDED by hand in all sorts of places.
This changes the logic so that instead, the PTE now contains
_PAGE_COHERENT for all normal RAM pages thay have I = 0 on platforms
that need it. The hash code clears it if the feature bit is not set.
It also adds some clean accessors to setup various valid combinations
of access flags and change various bits of code to use them instead.
This should help having the PTE actually containing the bit
combinations that we really want.
I also removed _PAGE_GUARDED from _PAGE_BASE on 44x and instead
set it explicitely from the TLB miss. I will ultimately remove it
completely as it appears that it might not be needed after all
but in the meantime, having it in the TLB miss makes things a
lot easier.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The typesafe version of the powerpc pagetable handling (with
USE_STRICT_MM_TYPECHECKS defined) has bitrotted again. This patch
makes a bunch of small fixes to get it back to building status.
It's still not enabled by default as gcc still generates worse
code with it for some reason.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This rearranges a bit of code, and adds support for
36-bit physical addressing for configs that use a
hashed page table. The 36b physical support is not
enabled by default on any config - it must be
explicitly enabled via the config system.
This patch *only* expands the page table code to accomodate
large physical addresses on 32-bit systems and enables the
PHYS_64BIT config option for 86xx. It does *not*
allow you to boot a board with more than about 3.5GB of
RAM - for that, SWIOTLB support is also required (and
coming soon).
Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Implement _PAGE_SPECIAL and pte_special() for 32-bit powerpc. This bit will
be used by the fast get_user_pages() to differenciate PTEs that correspond
to a valid struct page from special mappings that don't such as IO mappings
obtained via io_remap_pfn_ranges().
We currently only implement this on sub-arch that support SMP or will so
in the future (6xx, 44x, FSL-BookE) and not (8xx, 40x).
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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There are some minor issues with support 64-bit PTEs on a 32-bit processor
when dealing with SMP.
* We need to order the stores in set_pte_at to make sure the flag word
is set second.
* Change pte_clear to use pte_update so only the flag word is cleared
* Added a WARN_ON to set_pte_at to ensure the pte isn't present for
the 64-bit pte/SMP case (to ensure our assumption of this fact).
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Becky Bruce <becky.bruce@freescale.com>
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from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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