On ARMv7, it is invalid to map the same physical address multiple times
with different memory types. Since system RAM is already mapped as
'memory', subsequent remapping of it must retain this attribute.
However, DMA memory maps it as "strongly ordered". Fix this by introducing
'pgprot_dmacoherent()' which provides the necessary page table bits for
DMA mappings.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Add the ARM implementation of highpte, which allows PTE tables to be
placed in highmem. Unfortunately, we do not offer highpte support
when support for L2 cache is enabled.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
For future compatibility, we need to ensure that swap and file Linux
PTEs conform with the hardware PTEs "fault" encoding. Swap PTEs
already fit in with this, but file PTEs do not. Shift them by one
bit to ensure that they conform, using bit 2 to distinguish between
swap and file PTEs.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
These old symbols are meaningless now that we have memory type
support implemented. The entire memory type field needs to be
modified rather than just a few bits twiddled.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Document the layout of our swp PTE entries, adding definitions for
the bit masks/shifts/sizes, and implement MAX_SWAPFILES_CHECK()
such that we fail to build if we are unable to properly encode the
swp type field.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
In the long run, we may want to place page tables in highmem. However,
pmd_page() has traditionally been coded to convert the physical address
to a virtual one, which won't work with highmem pages. Instead,
translate the physical address to a PFN, and then convert the PFN to a
struct page instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add support for detecting non-executable stack binaries, and adjust
permissions to prevent execution from data and stack areas. Also,
ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that
is true, and for any executable-stack binary.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
As of the previous commit, MT_DEVICE_IXP2000 encodes to the same
PTE bit encoding as MT_DEVICE, so it's now redundant. Convert
MT_DEVICE_IXP2000 to use MT_DEVICE instead, and remove its aliases.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Provide L_PTE_MT_xxx definitions to describe the memory types that we
use in Linux/ARM. These definitions are carefully picked such that:
1. their LSBs match what is required for pre-ARMv6 CPUs.
2. they all have a unique encoding, including after modification
by build_mem_type_table() (the result being that some have more
than one combination.)
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Russell King