arm: use generic fixmap.h

ARM is different from other architectures in that fixmap pages are indexed
with a positive offset from FIXADDR_START.  Other architectures index with
a negative offset from FIXADDR_TOP.  In order to use the generic fixmap.h
definitions, this patch redefines FIXADDR_TOP to be inclusive of the
useable range.  That is, FIXADDR_TOP is the virtual address of the topmost
fixed page.  The newly defined FIXADDR_END is the first virtual address
past the fixed mappings.

Signed-off-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
[kees: update for a05e54c103b0 ("ARM: 8031/2: change fixmap ...")]
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Rob Herring <robh@kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: expand fixmap region to 3MB

With commit a05e54c103b0 ("ARM: 8031/2: change fixmap mapping region to
support 32 CPUs"), the fixmap region was expanded to 2MB, but it
precluded any other uses of the fixmap region. In order to support other
uses the fixmap region needs to be expanded beyond 2MB. Fortunately, the
adjacent 1MB range 0xffe00000-0xfff00000 is availabe.

Remove fixmap_page_table ptr and lookup the page table via the virtual
address so that the fixmap region can span more that one pmd. The 2nd
pmd is already created since it is shared with the vector page.

Signed-off-by: Rob Herring <robh@kernel.org>
[kees: fixed CONFIG_DEBUG_HIGHMEM get_fixmap() calls]
[kees: moved pte allocation outside of CONFIG_HIGHMEM]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
arm: fixmap: implement __set_fixmap()

This is used from set_fixmap() and clear_fixmap() via asm-generic/fixmap.h.
Also makes sure that the fixmap allocation fits into the expected range.

Based on patch by Rabin Vincent.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Rabin Vincent <rabin@rab.in>
Acked-by: Nicolas Pitre <nico@linaro.org>
arm: use fixmap for text patching when text is RO

Use fixmaps for text patching when the kernel text is read-only,
inspired by x86.  This makes jump labels and kprobes work with the
currently available CONFIG_DEBUG_SET_MODULE_RONX and the upcoming
CONFIG_DEBUG_RODATA options.

Signed-off-by: Rabin Vincent <rabin@rab.in>
[kees: fixed up for merge with "arm: use generic fixmap.h"]
[kees: added parse acquire/release annotations to pass C=1 builds]
[kees: always use stop_machine to keep TLB flushing local]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: kexec: Make .text R/W in machine_kexec

With the introduction of Kees Cook's patch to make the kernel .text
read-only the existing method by which kexec works got broken since it
directly pokes some values in the template code, which resides in the
.text section.

The current patch changes the way those values are inserted so that poking
.text section occurs only in machine_kexec (e.g when we are about to nuke
the old kernel and are beyond the point of return). This allows to use
set_kernel_text_rw() to directly patch the values in the .text section.

I had already sent a patch which achieved this but it was significantly
more complicated, so this is a cleaner/straight-forward approach.

Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
[kees: collapsed kexec_boot_atags (will.daecon)]
[kees: for bisectability, moved set_kernel_text_rw() to RODATA patch]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
arm: kgdb: Handle read-only text / modules

Handle the case where someone has set the text segment of the kernel
as read-only by using the newly introduced "patch" mechanism.

Signed-off-by: Doug Anderson <dianders@chromium.org>
[kees: switched structure size check to BUILD_BUG_ON (sboyd)]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: mm: allow non-text sections to be non-executable

Adds CONFIG_ARM_KERNMEM_PERMS to separate the kernel memory regions
into section-sized areas that can have different permisions. Performs
the NX permission changes during free_initmem, so that init memory can be
reclaimed.

This uses section size instead of PMD size to reduce memory lost to
padding on non-LPAE systems.

Based on work by Brad Spengler, Larry Bassel, and Laura Abbott.

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
ARM: mm: allow text and rodata sections to be read-only

This introduces CONFIG_DEBUG_RODATA, making kernel text and rodata
read-only. Additionally, this splits rodata from text so that rodata can
also be NX, which may lead to wasted memory when aligning to SECTION_SIZE.
The read-only areas are made writable during ftrace updates and kexec.

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
iommu/omap: Remove refcount field from omap_iommu object

The refcount field in omap_iommu object is primarily used to check
if an IOMMU device has already been enabled, but this is already
implicit in the omap_iommu_attach_dev() which ensures that only
a single device can attach to an IOMMU. This field is redundant,
and so has been cleaned up.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove unused isr_priv field from omap_iommu

The isr_priv field is a left-over from before the IOMMU API
adaptation, this was used to store the callback data. This is
no longer relevant, so remove it.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove duplicate declarations

The omap_iommu_save_ctx() and omap_iommu_restore_ctx() declarations
are defined in include/linux/omap-iommu.h and do not belong in the
internal drivers/iommu/omap-iommu.h header, so remove them.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove conditional definition of dev_to_omap_iommu()

The dev_to_omap_iommu() is local to the OMAP IOMMU modules, and
need not be defined conditionally. The CONFIG_IOMMU_API dependency
check was added in the past to fix a compilation issue back when
the header resided in the arch/arm layers, and is no longer
needed.

While at this, fix the header against double inclusion as well.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove ver debugfs entry

The debugfs entry 'ver' to read the OMAP IOMMU version is
not much useful for developers, so it has been removed. The
same can be deduced from the register dump, provided by the
debugfs entry 'regs', REVISION register. This also allows us
to remove the omap_iommu_arch_revision() which is currently
returning a fixed value.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove omap_iommu_arch_version() and version field

The function omap_iommu_arch_version() is not used anymore,
and is not required either, so remove it. The .version field
in struct iommu_functions that this function uses is also
removed, as it is not really an ops to retrieve a version and
there won't be any usage for this field either.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Remove bogus version check in context save/restore

The omap2_iommu_save_ctx() and omap2_iommu_restore_ctx()
performs a sanity version check against a fixed value
that is correct only for OMAP2/OMAP3 IOMMUs. This fixed check
does not scale for all OMAP2+ IOMMUs and is not absolutely
required, so it has been removed.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Simplify omap2_iommu_fault_isr()

The function omap2_iommu_fault_isr() does an unnecessary
recomputation of the return value. The logic relies on
setting the same bit fields as the MMU fault error status
bits, so simplify this function and remove the unneeded
macros. These macros were originally exported to notify
MMU faults to users prior to the IOMMU framework adaptation,
but are now redundant.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Consolidate OMAP IOMMU modules

The OMAP IOMMU driver was originally designed as modules, and split
into a core module and a thin arch-specific module through the OMAP
arch-specific struct iommu_functions, to scale for both OMAP1 and
OMAP2+ IOMMU variants. The driver can only be built for OMAP2+
platforms currently, and also can only be built-in after the
adaptation to generic IOMMU API. The OMAP1 variant was never added
and will most probably be never added (the code for the only potential
user, its parent, DSP processor has already been cleaned up). So,
consolidate the OMAP2 specific omap-iommu2 module into the core OMAP
IOMMU driver - this eliminates the arch-specific ops structure and
simplifies the driver into a single module that only implements the
generic IOMMU API's iommu_ops.

The following are the main changes:
- omap-iommu2 module is completely eliminated, with the common
  definitions moved to the internal omap-iommu.h, and the ops
  implementations moved into omap-iommu.c
- OMAP arch-specific struct iommu_functions is also eliminated,
  with the ops implementations directly absorbed into the calling
  functions
- iotlb_alloc_cr() is no longer inlined and defined only when
  PREFETCH_IOTLB is defined
- iotlb_dump_cr() is similarly defined only when CONFIG_OMAP_IOMMU_DEBUG
  is defined
- Elimination of the OMAP IOMMU exported functions to register the
  arch ops, omap_install_iommu_arch() & omap_uninstall_iommu_arch()
- Any stale comments about OMAP1 are also cleaned up

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Fix the permissions on nr_tlb_entries

The permissions on the debugfs entry "nr_tlb_entries" should
have been octal, not decimal, so fix it.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Make pagetable debugfs entry read-only

Remove the writeability on the 'pagetable' debugfs entry,
so that the mapping/unmapping into an OMAP IOMMU is only
limited to actual client devices/drivers at kernel-level.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
iommu/omap: Integrate omap-iommu-debug into omap-iommu

The debugfs support for OMAP IOMMU is currently implemented
as a module, warranting certain OMAP-specific IOMMU API to
be exported. The OMAP IOMMU, when enabled, can only be built-in
into the kernel, so integrate the OMAP IOMMU debug module
into the OMAP IOMMU driver. This helps in eliminating the
need to export most of the current OMAP IOMMU API.

The following are the main changes:
- The debugfs directory and entry creation logic is reversed,
  the calls are invoked by the OMAP IOMMU driver now.
- The current iffy circular logic of adding IOMMU archdata
  to the IOMMU devices itself to get a pointer to the omap_iommu
  object in the debugfs support code is replaced by directly
  using the omap_iommu structure while creating the debugfs
  entries.
- The debugfs root directory is renamed from the generic name
  "iommu" to a specific name "omap_iommu".
- Unneeded headers have also been cleaned up while at this.
- There will no longer be a omap-iommu-debug.ko module after
  this patch.
- The OMAP_IOMMU_DEBUG Kconfig option is converted to boolean
  only, the OMAP IOMMU debugfs support is built alongside the
  OMAP IOMMU driver only when this option is enabled.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>