On some PAE systems (e.g. TI Keystone), memory is above the
32-bit addressable limit, and the interconnect provides an
aliased view of parts of physical memory in the 32-bit addressable
space.  This alias is strictly for boot time usage, and is not
otherwise usable because of coherency limitations. On such systems,
the idmap mechanism needs to take this aliased mapping into account.

This patch introduces virt_to_idmap() and a arch function pointer which
can be populated by platform which needs it. Also populate necessary
idmap spots with now available virt_to_idmap(). Avoided #ifdef approach
to be compatible with multi-platform builds.

Most architecture won't touch it and in that case virt_to_idmap()
fall-back to existing virt_to_phys() macro.

Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>

Fix remainder types used when converting back and forth between
physical and virtual addresses.

Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>

VALID_PAGE() has been removed from kernel long time ago,
so fix the comment.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Giancarlo Asnaghi <giancarlo.asnaghi@st.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On LPAE machines, PHYS_OFFSET evaluates to a phys_addr_t and this type is
inherited by the PHYS_PFN_OFFSET definition as well.  Consequently, the kernel
build emits warnings of the form:

init/main.c: In function 'start_kernel':
init/main.c:588:7: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'phys_addr_t' [-Wformat]

This patch fixes this warning by pinning down the PFN type to unsigned long.
Signed-off-by: NCyril Chemparathy <cyril@ti.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NSubash Patel <subash.rp@samsung.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch redefines the early boot time use of the R4 register to steal a few
low order bits (ARCH_PGD_SHIFT bits) on LPAE systems.  This allows for up to
38-bit physical addresses.
Signed-off-by: NCyril Chemparathy <cyril@ti.com>
Signed-off-by: NVitaly Andrianov <vitalya@ti.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NSubash Patel <subash.rp@samsung.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Parts of the virtual memory layout (mainly the modules area) are
described using open-coded immediate values.

Use the SZ_ definitions from linux/sizes.h instead to make the code
clearer.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We are getting a number of warnings about the use of the deprecated
bus_to_virt function in drivers using the ARM ISA DMA API:

drivers/parport/parport_pc.c: In function 'parport_pc_fifo_write_block_dma':
drivers/parport/parport_pc.c:622:3: warning: 'bus_to_virt' is deprecated
(declared at arch/arm/include/asm/memory.h:253) [-Wdeprecated-declarations]

This is only because that function gets used by the inline
set_dma_addr() helper. We know that any driver for the ISA DMA API
is correctly using the DMA addresses, so we can change this
to use the __bus_to_virt() function instead, which does not warn.

After this, there are no remaining drivers that are used on
any defconfigs on ARM using virt_to_bus or bus_to_virt, with
the exception of the OSS sound driver. That driver is only used
on RiscPC, NetWinder and Shark, so we can set ARCH_NO_VIRT_TO_BUS
on all other platforms and hide the deprecated functions, which
is far more effective than marking them as deprecated, in order
to avoid any new users of that code.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>

We have received multiple reports of mmap failures when running with a
2:2 vm split. These manifest as either -EINVAL with a non page-aligned
address (ending 0xaaa) or a SEGV, depending on the application. The
issue is commonly observed in children of make, which appears to use
bottom-up mmap (assumedly because it changes the stack rlimit).

Further investigation reveals that this regression was triggered by
394ef640 ("mm: use vm_unmapped_area() on arm architecture"), whereby
TASK_UNMAPPED_BASE is no longer page-aligned for bottom-up mmap, causing
get_unmapped_area to choke on misaligned addressed.

This patch fixes the problem by defining TASK_UNMAPPED_BASE in terms of
TASK_SIZE and explicitly aligns the result to 16M, matching the other
end of the heap.
Acked-by: NNicolas Pitre <nico@linaro.org>
Reported-by: NSteve Capper <steve.capper@arm.com>
Reported-by: NJean-Francois Moine <moinejf@free.fr>
Reported-by: NChristoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

With ixp2xxx removed, there are no platforms that define arch_is_coherent,
so the last occurrences of arch_is_coherent can be removed. Any new
platform with coherent i/o should use coherent dma mapping functions.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

During the p2v changes, the PHYS_OFFSET #define moved into a
!__ASSEMBLY__ section. This causes a XIP build to fail with

 arch/arm/kernel/head.o: In function 'stext':
 arch/arm/kernel/head.S:146: undefined reference to 'PHYS_OFFSET'

Momentarily leave the #ifndef __ASSEMBLY__ section so we can
define PHYS_OFFSET for all compilation units.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NAlessandro Rubini <rubini@gnudd.com>
Acked-by: NGiancarlo Asnaghi <giancarlo.asnaghi@st.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

XIP_VIRT_ADDR is needed for XIP builds and currently only defined for
builds with CONFIG_MMU.

Also provide it for no-MMU builds to make it possible to build an XIP
kernel for MMU-less machines. As these lack an MMU it has to be an
identity mapping.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Given that we want the default to not have any <mach/memory.h> and given
that there are now fewer cases where it is still provided than the cases
where it is not at this point, this makes sense to invert the logic and
just identify the exception cases.

The word "need" instead of "have" was chosen to construct the config
symbol so not to suggest that having a mach/memory.h file is actually
a feature that one should aim for.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>

When the CONFIG_NO_MACH_MEMORY_H symbol is selected by a particular
machine class, the machine specific memory.h include file is no longer
used and can be removed.  In that case the equivalent information can
be obtained dynamically at runtime by enabling CONFIG_ARM_PATCH_PHYS_VIRT
or by specifying the physical memory address at kernel configuration time.

If/when all instances of mach/memory.h are removed then this symbol could
be removed.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>

This function can be called during boot to increase the size of the consistent
DMA region above it's default value of 2MB. It must be called before the memory
allocator is initialised, i.e. before any core_initcall.
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>

This code can be removed now that MSM targets no longer need the 16-bit
offsets for P2V.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ISA_DMA_THRESHOLD has been unused by non-arch code, so lets now get
rid of it from ARM by replacing it with arm_dma_zone_mask.  Move
dma_supported() and dma_set_mask() out of line, and have
dma_supported() check this new variable instead.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Rather than each platform providing its own function to adjust the
zone sizes, use the new ARM_DMA_ZONE_SIZE definition to perform this
adjustment.  This ensures that the actual DMA zone size and the
ISA_DMA_THRESHOLD/MAX_DMA_ADDRESS definitions are consistent with
each other, and moves this complexity out of the platform code.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The values of ISA_DMA_THRESHOLD and MAX_DMA_ADDRESS are related; one is
the physical/bus address, the other is the virtual address.  Both need
to be kept in step, so rather than having platforms define both, allow
them to define a single macro which sets both of these macros
appropraitely.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The unsigned long datatype is not sufficient for mapping physical addresses
>= 4GB.

This patch ensures that the address conversion code in asm/memory.h casts
to the correct type when handling physical addresses. The internal v2p
macros only deal with lowmem addresses, so these do not need to be modified.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

MSM's memory is aligned to 2MB, which is more than we can do with our
existing method as we're limited to the upper 8 bits.  Extend this by
using two instructions to 16 bits, automatically selected when MSM is
enabled.
Acked-by: NTony Lindgren <tony@atomide.com>
Reviewed-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This idea came from Nicolas, Eric Miao produced an initial version,
which was then rewritten into this.

Patch the physical to virtual translations at runtime.  As we modify
the code, this makes it incompatible with XIP kernels, but allows us
to achieve this with minimal loss of performance.

As many translations are of the form:

	physical = virtual + (PHYS_OFFSET - PAGE_OFFSET)
	virtual = physical - (PHYS_OFFSET - PAGE_OFFSET)

we generate an 'add' instruction for __virt_to_phys(), and a 'sub'
instruction for __phys_to_virt().  We calculate at run time (PHYS_OFFSET
- PAGE_OFFSET) by comparing the address prior to MMU initialization with
where it should be once the MMU has been initialized, and place this
constant into the above add/sub instructions.

Once we have (PHYS_OFFSET - PAGE_OFFSET), we can calculate the real
PHYS_OFFSET as PAGE_OFFSET is a build-time constant, and save this for
the C-mode PHYS_OFFSET variable definition to use.

At present, we are unable to support Realview with Sparsemem enabled
as this uses a complex mapping function, and MSM as this requires a
constant which will not fit in our math instruction.

Add a module version magic string for this feature to prevent
incompatible modules being loaded.
Tested-by: NTony Lindgren <tony@atomide.com>
Reviewed-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This uncouple PHYS_OFFSET from the platform definitions, thereby
facilitating run-time computation of the physical memory offset.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@st.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NMagnus Damm <damm@opensource.se>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: NWan ZongShun <mcuos.com@gmail.com>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Acked-by: NEric Miao <eric.y.miao@gmail.com>
Acked-by: NJiandong Zheng <jdzheng@broadcom.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Changing the virt_to_phys() argument to "const volatile void *" avoids
compiler warnings in some situations where this function is used.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This changes the TCM handling so that a fixed area is reserved at
0xfffe0000-0xfffeffff for TCM. This areas is used by XScale but
XScale does not have TCM so the mechanisms are mutually exclusive.

This change is needed to make TCM detection more dynamic while
still being able to compile code into it, and is a must for the
unified ARM goals: the current TCM allocation at different places
in memory for each machine would be a nightmare if you want to
compile a single image for more than one machine with TCM so it
has to be nailed down in one place.
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Since we no longer support discontigmem, node is always zero, so
remove this argument.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Everything should now be using sparsemem rather than discontigmem, so
remove the code supporting discontigmem from ARM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Makes it consistent with VMALLOC_START
Tested-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NAndreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Adds DMA area to 'virtual memory map' startup message
Tested-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NAndreas Fenkart <andreas.fenkart@streamunlimited.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The non-highmem() and the __pfn_to_bus() based page_to_dma() both
compile to the same code, so its pointless having these two different
approaches.  Use the __pfn_to_bus() based version.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-By: NJamie Iles <jamie@jamieiles.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-By: NJamie Iles <jamie@jamieiles.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>

This reverts commit 75f4aa15.

We have a couple of platforms which require non-linear P:V mappings,
so we need these to be overridable.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

On OMAP platforms, some people want to declare to segment up the memory
between the kernel and a separate application such that there is a hole
in the middle of the memory as far as Linux is concerned.  However,
they want to be able to mmap() the hole.

This currently causes problems, because update_mmu_cache() thinks that
there are valid struct pages for the "hole".  Fix this by making
pfn_valid() slightly more expensive, by checking whether the PFN is
contained within the meminfo array.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: NKhasim Syed Mohammed <khasim@ti.com>

Modules compiled to Thumb-2 have two additional relocations needing to
be resolved at load time, R_ARM_THM_CALL and R_ARM_THM_JUMP24, for BL
and B.W instructions. The maximum Thumb-2 addressing range is +/-2^24
(+/-16MB) therefore the MODULES_VADDR macro in asm/memory.h is set to
(MODULES_END - 8MB) for the Thumb-2 compiled kernel.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

If a machine class has a custom __virt_to_bus() implementation then it
must provide a __arch_page_to_dma() implementation as well which is
_not_ based on page_address() to support highmem.

This patch fixes existing __arch_page_to_dma() and provide a default
implementation otherwise.  The default implementation for highmem is
based on __pfn_to_bus() which is defined only when no custom
__virt_to_bus() is provided by the machine class.

That leaves only ebsa110 and footbridge which cannot support highmem
until they provide their own __arch_page_to_dma() implementation.
But highmem support on those legacy platforms with limited memory is
certainly not a priority.
Signed-off-by: NNicolas Pitre <nico@marvell.com>

The kmap virtual area borrows a 2MB range at the top of the 16MB area
below PAGE_OFFSET currently reserved for kernel modules and/or the
XIP kernel.  This 2MB corresponds to the range covered by 2 consecutive
second-level page tables, or a single pmd entry as seen by the Linux
page table abstraction.  Because XIP kernels are unlikely to be seen
on systems needing highmem support, there shouldn't be any shortage of
VM space for modules (14 MB for modules is still way more than twice the
typical usage).

Because the virtual mapping of highmem pages can go away at any moment
after kunmap() is called on them, we need to bypass the delayed cache
flushing provided by flush_dcache_page() in that case.

The atomic kmap versions are based on fixmaps, and
__cpuc_flush_dcache_page() is used directly in that case.
Signed-off-by: NNicolas Pitre <nico@marvell.com>

Let's provide an overridable default instead of having every machine
class define __virt_to_bus and __bus_to_virt to the same thing.  What
most platforms are using is bus_addr == phys_addr so such is the default.

One exception is ebsa110 which has no DMA what so ever, so the actual
definition is not important except only for proper compilation.  Also
added a comment about the special footbridge bus translation.

Let's also remove comments alluding to set_dma_addr which is not
(and should not) be commonly used.
Signed-off-by: NNicolas Pitre <nico@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There is no machine class overriding this.  If non linear translations
are implemented again for some machines then this could be restored at
that time.
Signed-off-by: NNicolas Pitre <nico@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As of 73bdf0a6, the kernel needs
to know where modules are located in the virtual address space.
On ARM, we located this region between MODULE_START and MODULE_END.
Unfortunately, everyone else calls it MODULES_VADDR and MODULES_END.
Update ARM to use the same naming, so is_vmalloc_or_module_addr()
can work properly.  Also update the comment on mm/vmalloc.c to
reflect that ARM also places modules in a separate region from the
vmalloc space.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Most ARM machines don't need a special "DMA" memory zone, and
when configured out, the kernel becomes a bit smaller:

|   text    data     bss     dec     hex filename
|3826182  102384  111700 4040266  3da64a vmlinux
|3823593  101616  111700 4036909  3d992d vmlinux.nodmazone

This is because the system now has only one zone total which effect is
to optimize away many conditionals in page allocation paths.

So let's configure this zone only on machines that need split zones.
Signed-off-by: NNicolas Pitre <nico@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>