The pte_accessible macro can be used to identify page table entries
capable of being cached by a TLB. In principle, this differs from
pte_present, since PROT_NONE mappings are mapped using invalid entries
identified as present and ptes designated as `old' can use either
invalid entries or those with the access flag cleared (guaranteed not to
be in the TLB). However, there is a race to take care of, as described
in 2084140594 ("mm: fix TLB flush race between migration, and
change_protection_range"), between a page being migrated and mprotected
at the same time. In this case, we can check whether a TLB invalidation
is pending for the mm and if so, temporarily consider PROT_NONE mappings
as valid.
This patch implements a quick pte_accessible macro for ARM by simply
checking if the pte is valid/present depending on the mm. For classic
MMU, these checks are identical and will generate some false positives
for PROT_NONE mappings, but this is better than the current asm-generic
definition of ((void)(pte),1).
Finally, pte_present_user is moved to use pte_valid (and renamed
appropriately) since we don't care about cache flushing for faulting
mappings.
Acked-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Other architectures define pte_mkexec to mark a pte as executable.
Add pte_mkexec for ARM to get the same functionality. Although no
other architectures currently define it, also add pte_mknexec to
explicitly allow a pte to be marked as non executable.
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit f6f91b0d9f (ARM: allow kuser helpers to be removed from the
vector page) required two pages for the vectors code. Although the
code setting up the initial page tables was updated, the code which
allocates page tables for new processes wasn't, neither was the code
which tears down the mappings. Fix this.
Fixes: f6f91b0d9f ("ARM: allow kuser helpers to be removed from the vector page")
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: <stable@vger.kernel.org>
THe L_PTE_USER actually has nothing to do with stage 2 mappings and the
L_PTE_S2_RDWR value sets the readable bit, which was what L_PTE_USER
was used for before proper handling of stage 2 memory defines.
Changelog:
[v3]: Drop call to kvm_set_s2pte_writable in mmu.c
[v2]: Change default mappings to be r/w instead of r/o, as per Marc
Zyngier's suggestion.
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull ARM updates from Russell King:
"This contains the usual updates from other people (listed below) and
the usual random muddle of miscellaneous ARM updates which cover some
low priority bug fixes and performance improvements.
I've started to put the pull request wording into the merge commits,
which are:
- NoMMU stuff:
This includes the following series sent earlier to the list:
- nommu-fixes
- R7 Support
- MPU support
I've left out the ARCH_MULTIPLATFORM/!MMU stuff that Arnd and I
were discussing today until we've reached a conclusion/that's had
some more review.
This is rebased (and re-tested) on your devel-stable branch because
otherwise there were going to be conflicts with Uwe's V7M work now
that you've merged that. I've included the fix for limiting MPU to
CPU_V7.
- Huge page support
These changes bring both HugeTLB support and Transparent HugePage
(THP) support to ARM. Only long descriptors (LPAE) are supported
in this series.
The code has been tested on an Arndale board (Exynos 5250).
- LPAE updates
Please pull these miscellaneous LPAE fixes I've been collecting for
a while now for 3.11. They've been tested and reviewed by quite a
few people, and most of the patches are pretty trivial. -- Will Deacon.
- arch_timer cleanups
Please pull these arch_timer cleanups I've been holding onto for a
while. They're the same as my last posting, but have been rebased
to v3.10-rc3.
- mpidr linearisation (multiprocessor id register - identifies which
CPU number we are in the system)
This patch series that implements MPIDR linearization through a
simple hashing algorithm and updates current cpu_{suspend}/{resume}
code to use the newly created hash structures to retrieve context
pointers. It represents a stepping stone for the implementation of
power management code on forthcoming multi-cluster ARM systems.
It has been tested on TC2 (dual cluster A15xA7 system), iMX6q,
OMAP4 and Tegra, with processors hitting low-power states requiring
warm-boot resume through the cpu_resume code path"
* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (77 commits)
ARM: 7775/1: mm: Remove do_sect_fault from LPAE code
ARM: 7777/1: Avoid extra calls to the C compiler
ARM: 7774/1: Fix dtb dependency to use order-only prerequisites
ARM: 7770/1: remove residual ARMv2 support from decompressor
ARM: 7769/1: Cortex-A15: fix erratum 798181 implementation
ARM: 7768/1: prevent risks of out-of-bound access in ASID allocator
ARM: 7767/1: let the ASID allocator handle suspended animation
ARM: 7766/1: versatile: don't mark pen as __INIT
ARM: 7765/1: perf: Record the user-mode PC in the call chain.
ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork
ARM: kernel: implement stack pointer save array through MPIDR hashing
ARM: kernel: build MPIDR hash function data structure
ARM: mpu: Ensure that MPU depends on CPU_V7
ARM: mpu: protect the vectors page with an MPU region
ARM: mpu: Allow enabling of the MPU via kconfig
ARM: 7758/1: introduce config HAS_BANDGAP
ARM: 7757/1: mm: don't flush icache in switch_mm with hardware broadcasting
ARM: 7751/1: zImage: don't overwrite ourself with a page table
ARM: 7749/1: spinlock: retry trylock operation if strex fails on free lock
ARM: 7748/1: oabi: handle faults when loading swi instruction from userspace
...
The patch adds support for THP (transparent huge pages) to LPAE
systems. When this feature is enabled, the kernel tries to map
anonymous pages as 2MB sections where possible.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[steve.capper@linaro.org: symbolic constants used, value of
PMD_SECT_SPLITTING adjusted, tlbflush.h included in pgtable.h,
added PROT_NONE support.]
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
ARM processors with LPAE enabled use 3 levels of page tables, with an
entry in the top level (pgd) covering 1GB of virtual space. Because of
the branch relocation limitations on ARM, the loadable modules are
mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared
between kernel modules and user space.
If free_pgtables() is called with the default ceiling 0,
free_pgd_range() (and subsequently called functions) also frees the page
table shared between user space and kernel modules (which is normally
handled by the ARM-specific pgd_free() function). This patch changes
defines the ARM USER_PGTABLES_CEILING to TASK_SIZE when CONFIG_ARM_LPAE
is enabled.
Note that the pgd_free() function already checks the presence of the
shared pmd page allocated by pgd_alloc() and frees it, though with
ceiling 0 this wasn't necessary.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org> [3.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Following commit 26ffd0d4 (ARM: mm: introduce present, faulting entries
for PAGE_NONE), if a page has been mapped as PROT_NONE, the L_PTE_VALID
bit is cleared by the set_pte_ext() code. With LPAE the software and
hardware pte share the same location and subsequent modifications of pte
range (change_protection()) will leave the L_PTE_VALID bit cleared.
This patch adds the L_PTE_VALID bit to the newprot mask in pte_modify().
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Subash Patel <subash.rp@samsung.com>
Tested-by: Subash Patel <subash.rp@samsung.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> # 3.8.x
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
KVM uses the stage-2 page tables and the Hyp page table format,
so we define the fields and page protection flags needed by KVM.
The nomenclature is this:
- page_hyp: PL2 code/data mappings
- page_hyp_device: PL2 device mappings (vgic access)
- page_s2: Stage-2 code/data page mappings
- page_s2_device: Stage-2 device mappings (vgic access)
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Christoffer Dall <c.dall@virtualopensystems.com>
PROT_NONE mappings apply the page protection attributes defined by _P000
which translate to PAGE_NONE for ARM. These attributes specify an XN,
RDONLY pte that is inaccessible to userspace. However, on kernels
configured without support for domains, such a pte *is* accessible to
the kernel and can be read via get_user, allowing tasks to read
PROT_NONE pages via syscalls such as read/write over a pipe.
This patch introduces a new software pte flag, L_PTE_NONE, that is set
to identify faulting, present entries.
Signed-off-by: Will Deacon <will.deacon@arm.com>
For long-descriptor translation table formats, the ARMv7 architecture
defines the last two bits of the second- and third-level descriptors to
be:
x0b - Invalid
01b - Block (second-level), Reserved (third-level)
11b - Table (second-level), Page (third-level)
This allows us to define L_PTE_PRESENT as (3 << 0) and use this value to
create ptes directly. However, when determining whether a given pte
value is present in the low-level page table accessors, we only need to
check the least significant bit of the descriptor, allowing us to write
faulting, present entries which are required for PROT_NONE mappings.
This patch introduces L_PTE_VALID, which can be used to test whether a
pte should fault, and updates the low-level page table accessors
accordingly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Convert #include "..." to #include <path/...> in kernel system headers.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
Page migration encodes the pfn in the offset field of a swp_entry_t.
For LPAE, we support physical addresses of up to 36 bits (due to
sparsemem limitations with the size of page flags), requiring 24 bits
to represent a pfn. A further 3 bits are used to encode a swp_entry into
a pte, leaving 5 bits for the type field. Furthermore, the core code
defines MAX_SWAPFILES_SHIFT as 5, so the additional type bit does not
get used.
This patch reduces the width of the type field to 5 bits, allowing us
to create up to 31 swapfiles of 64GB each.
Cc: <stable@vger.kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Swap entries are encoding in ptes such that !pte_present(pte) and
pte_file(pte). The remaining bits of the descriptor are used to identify
the swapfile and offset within it to the swap entry.
When writing such a pte for a user virtual address, set_pte_at
unconditionally sets the nG bit, which (in the case of LPAE) will
corrupt the swapfile offset and lead to a BUG:
[ 140.494067] swap_free: Unused swap offset entry 000763b4
[ 140.509989] BUG: Bad page map in process rs:main Q:Reg pte:0ec76800 pmd:8f92e003
This patch fixes the problem by only setting the nG bit for user
mappings that are actually present.
Cc: <stable@vger.kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch introduces the pgtable-3level*.h files with definitions
specific to the LPAE page table format (3 levels of page tables).
Each table is 4KB and has 512 64-bit entries. An entry can point to a
40-bit physical address. The young, write and exec software bits share
the corresponding hardware bits (negated). Other software bits use spare
bits in the PTE.
The patch also changes some variable types from unsigned long or int to
pteval_t or pgprot_t.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The page table maintenance macros need to be duplicated between the
classic and the LPAE MMU so this patch moves those that are not common
to the pgtable-2level.h file.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Nick Piggin noted upon introducing 4level-fixup.h:
| Add a temporary "fallback" header so architectures can run with
| the 4level pagetables patch without modification. All architectures
| should be converted to use the folding headers (include/asm-generic/
| pgtable-nop?d.h) as soon as possible, and the fallback header removed.
This makes ARM compliant with this statement.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When disabling and re-enabling the MMU, it is necessary to take out an
identity mapping for the code that manipulates the SCTLR in order to
avoid it disappearing from under our feet. This is useful when soft
rebooting and returning from CPU suspend.
This patch allocates a set of page tables during boot and populates them
with an identity mapping for the .idmap.text section. This means that
users of the identity map do not need to manage their own pgd and can
instead annotate their functions with __idmap or, in the case of assembly
code, place them in the correct section.
Acked-by: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Similar to other architectures, this adds topdown mmap support in user
process address space allocation policy. This allows mmap sizes greater
than 2GB. This support is largely copied from MIPS and the generic
implementations.
The address space randomization is moved into arch_pick_mmap_layout.
Tested on V-Express with ubuntu and a mmap test from here:
https://bugs.launchpad.net/bugs/861296
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
THIS IS A TEMPORARY HACK. The purpose of this is _only_ to avoid a
regression on an existing machine while a better fix is implemented.
On shmobile the consistent DMA memory area was set to 158MB in commit
28f0721a79 with no explanation. The documented size for this area should
vary between 2MB and 14MB, and none of the other ARM targets exceed that.
The included #warning is therefore meant to be noisy on purpose to get
shmobile maintainers attention and this commit reverted once this
consistent DMA size conflict is resolved.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Magnus Damm <damm@opensource.se>
Cc: Paul Mundt <lethal@linux-sh.org>
In order to remove the build time variation between different SOCs with
regards to VMALLOC_END, the iotable mappings are now allocated inside
the vmalloc region. This allows for VMALLOC_END to be identical across
all machines.
The value for VMALLOC_END is now set to 0xff000000 which is right where
the consistent DMA area starts.
To accommodate all static mappings on machines with possible highmem usage,
the default vmalloc area size is changed to 240 MB so that VMALLOC_START
is no higher than 0xf0000000 by default.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Tested-by: Jamie Iles <jamie@jamieiles.com>
With LPAE, the physical address mask is 40-bit while the page table
entry is 64-bit. This patch introduces PHYS_MASK for the 2-level page
table format, defined as ~0UL.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch moves page table definitions from asm/page.h, asm/pgtable.h
and asm/ptgable-hwdef.h into corresponding *-2level* files.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On certain architectures, there might be a need to mark certain
addresses with strongly ordered memory attributes to avoid ordering
issues at the interconnect level.
On OMAP4, the asynchronous bridge buffers can only be drained
with strongly ordered accesses and hence the need to mark the
memory strongly ordered.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Woodruff Richard <r-woodruff2@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Add pud_offset() et.al. between the pgd and pmd code in preparation of
using pgtable-nopud.h rather than 4level-fixup.h.
This incorporates a fix from Jamie Iles <jamie@jamieiles.com> for
uaccess_with_memcpy.c.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The unsigned long datatype is not sufficient for mapping physical addresses
>= 4GB.
This patch ensures that the phys_addr_t datatype is used to represent physical
addresses when converting from a PFN.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The hardware page tables use an XN bit 'execute never'. Historically,
we've had a Linux 'execute allow' bit, in the positive sense. Get rid
of this artifact as future hardware will continue to have the XN sense.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
FIRST_USER_PGD_NR is now unnecessary, as this has been replaced by
FIRST_USER_ADDRESS except in the architecture code. Fix up the last
usage of FIRST_USER_PGD_NR, and remove the definition.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We have two places where we create identity mappings - one when we bring
secondary CPUs online, and one where we setup some mappings for soft-
reboot. Combine these two into a single implementation. Also collect
the identity mapping deletion function.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This switches the ordering of the Linux vs hardware page tables in
each page, thereby eliminating some of the arithmetic in the page
table walks. As we now place the Linux page table at the beginning
of the page, we can deal with the offset in the pgt by simply masking
it away, along with the other control bits.
This also makes the arithmetic all be positive, rather than a mixture.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than passing the pte value to __pte_error, pass the raw pte_t
cookie instead. Do the same for pmd and pgd functions.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Allow the compiler to better optimize the page table walking code
by avoiding over-complex pmd_addr_end() calculations. These
calculations prevent the compiler spotting that we'll never iterate
over the PMD table, causing it to create double nested loops where
a single loop will do.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since we no longer need to provide KM_type, the whole pte_*map_nested()
API is now redundant, remove it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ARMv7 onwards requires that there are no aliases to the same physical
location using different memory types (i.e. Normal vs Strongly Ordered).
Access to SO mappings when the unaligned accesses are handled in
hardware is also Unpredictable (pgprot_noncached() mappings in user
space).
The /dev/mem driver requires uncached mappings with O_SYNC. The patch
implements the phys_mem_access_prot() function which generates Strongly
Ordered memory attributes if !pfn_valid() (independent of O_SYNC) and
Normal Noncacheable (writecombine) if O_SYNC.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Will Deacon