Commit Graph

22 Commits

Author SHA1 Message Date
Linus Torvalds
7782aae498 ARM development updates for 6.1-rc1
- Print an un-hashed userspace PC on undefined instruction exception
 - Disable FDPIC ABI
 - Remove redundant vfp_flush/release_thread functions
 - Use raw_cpu_* rather than this_cpu_* in handle_bad_stack()
 - Avoid needlessly long backtraces when show_regs() is called
 - Fix an issue with stack traces through call_with_stack()
 - Avoid stack traces saving a duplicate exception PC value
 - Pass a void pointer to virt_to_page() in DMA mapping code
 - Fix kasan maps for modules when CONFIG_KASAN_VMALLOC=n
 - Show FDT region and page table level names in kernel page tables dump
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:

 - Print an un-hashed userspace PC on undefined instruction exception

 - Disable FDPIC ABI

 - Remove redundant vfp_flush/release_thread functions

 - Use raw_cpu_* rather than this_cpu_* in handle_bad_stack()

 - Avoid needlessly long backtraces when show_regs() is called

 - Fix an issue with stack traces through call_with_stack()

 - Avoid stack traces saving a duplicate exception PC value

 - Pass a void pointer to virt_to_page() in DMA mapping code

 - Fix kasan maps for modules when CONFIG_KASAN_VMALLOC=n

 - Show FDT region and page table level names in kernel page tables dump

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9246/1: dump: show page table level name
  ARM: 9245/1: dump: show FDT region
  ARM: 9242/1: kasan: Only map modules if CONFIG_KASAN_VMALLOC=n
  ARM: 9240/1: dma-mapping: Pass (void *) to virt_to_page()
  ARM: 9234/1: stacktrace: Avoid duplicate saving of exception PC value
  ARM: 9233/1: stacktrace: Skip frame pointer boundary check for call_with_stack()
  ARM: 9224/1: Dump the stack traces based on the parameter 'regs' of show_regs()
  ARM: 9232/1: Replace this_cpu_* with raw_cpu_* in handle_bad_stack()
  ARM: 9228/1: vfp: kill vfp_flush/release_thread()
  ARM: 9226/1: disable FDPIC ABI
  ARM: 9221/1: traps: print un-hashed user pc on undefined instruction
2022-10-06 10:32:34 -07:00
Wang Kefeng
e66372ecb8 ARM: 9246/1: dump: show page table level name
ARM could have 3 page table level if ARM_LPAE enabled, or only 2 page
table level, let's show the page table level name when dump.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-10-04 11:09:48 +01:00
Wang Kefeng
afd1efa1d8 ARM: 9245/1: dump: show FDT region
Since commit 7a1be318f5 ("ARM: 9012/1: move device tree mapping out
of linear region"), FDT is placed between the end of the vmalloc region
and the start of the fixmap region, let's show it in dump.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-10-04 11:09:48 +01:00
Wang Kefeng
2ccd19b3ff ARM: 9244/1: dump: Fix wrong pg_level in walk_pmd()
After ARM supports p4d page tables, the pg_level for note_page()
in walk_pmd() should be 4, not 3, fix it.

Fixes: 84e6ffb2c4 ("arm: add support for folded p4d page tables")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-09-22 08:29:03 +01:00
Jisheng Zhang (syna)
a5e8acd94f ARM: 9073/1: ptdump: add __init section marker to three functions
They are not needed after booting, so mark them as __init to move them
to the .init section.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2021-04-18 19:15:12 +01:00
Hailong Liu
b53a9edcde ARM: 9053/1: arm/mm/ptdump:Add address markers for KASAN regions
ARM has recently supported KASAN, so I think that it's time to add
KASAN regions for PTDUMP on ARM.

This patch has been tested with QEMU + vexpress-a15. Both
CONFIG_ARM_LPAE and no CONFIG_ARM_LPAE.

The result after patching looks like this:
 ---[ Kasan shadow start ]---
 0x6ee00000-0x7af00000         193M     RW NX SHD MEM/CACHED/WBWA
 0x7b000000-0x7f000000          64M     ro NX SHD MEM/CACHED/WBWA
 ---[ Kasan shadow end ]---
 ---[ Modules ]---
 ---[ Kernel Mapping ]---
	......
 ---[ vmalloc() Area ]---
	......
 ---[ vmalloc() End ]---
 ---[ Fixmap Area ]---
 ---[ Vectors ]---
 	......
 ---[ Vectors End ]---

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hailong liu <liu.hailong6@zte.com.cn>
Signed-off-by: Hailong liu <carver4lio@163.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2021-02-01 19:48:06 +00:00
Mike Rapoport
e31cf2f4ca mm: don't include asm/pgtable.h if linux/mm.h is already included
Patch series "mm: consolidate definitions of page table accessors", v2.

The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once.  For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.

Most of these definitions are actually identical and typically it boils
down to, e.g.

static inline unsigned long pmd_index(unsigned long address)
{
        return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.

For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.

These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.

This patch (of 12):

The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g.  pte_alloc() and
pmd_alloc().  So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.

The include statements in such cases are remove with a simple loop:

	for f in $(git grep -l "include <linux/mm.h>") ; do
		sed -i -e '/include <asm\/pgtable.h>/ d' $f
	done

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:13 -07:00
Mike Rapoport
84e6ffb2c4 arm: add support for folded p4d page tables
Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, and remove __ARCH_USE_5LEVEL_HACK.

[rppt@linux.ibm.com: fix kexec]
  Link: http://lkml.kernel.org/r/20200508174232.GA759899@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04 19:06:21 -07:00
Linus Torvalds
f632a8170a Driver Core and debugfs changes for 5.3-rc1
Here is the "big" driver core and debugfs changes for 5.3-rc1
 
 It's a lot of different patches, all across the tree due to some api
 changes and lots of debugfs cleanups.  Because of this, there is going
 to be some merge issues with your tree at the moment, I'll follow up
 with the expected resolutions to make it easier for you.
 
 Other than the debugfs cleanups, in this set of changes we have:
 	- bus iteration function cleanups (will cause build warnings
 	  with s390 and coresight drivers in your tree)
 	- scripts/get_abi.pl tool to display and parse Documentation/ABI
 	  entries in a simple way
 	- cleanups to Documenatation/ABI/ entries to make them parse
 	  easier due to typos and other minor things
 	- default_attrs use for some ktype users
 	- driver model documentation file conversions to .rst
 	- compressed firmware file loading
 	- deferred probe fixes
 
 All of these have been in linux-next for a while, with a bunch of merge
 issues that Stephen has been patient with me for.  Other than the merge
 issues, functionality is working properly in linux-next :)
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and debugfs updates from Greg KH:
 "Here is the "big" driver core and debugfs changes for 5.3-rc1

  It's a lot of different patches, all across the tree due to some api
  changes and lots of debugfs cleanups.

  Other than the debugfs cleanups, in this set of changes we have:

   - bus iteration function cleanups

   - scripts/get_abi.pl tool to display and parse Documentation/ABI
     entries in a simple way

   - cleanups to Documenatation/ABI/ entries to make them parse easier
     due to typos and other minor things

   - default_attrs use for some ktype users

   - driver model documentation file conversions to .rst

   - compressed firmware file loading

   - deferred probe fixes

  All of these have been in linux-next for a while, with a bunch of
  merge issues that Stephen has been patient with me for"

* tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (102 commits)
  debugfs: make error message a bit more verbose
  orangefs: fix build warning from debugfs cleanup patch
  ubifs: fix build warning after debugfs cleanup patch
  driver: core: Allow subsystems to continue deferring probe
  drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT
  arch_topology: Remove error messages on out-of-memory conditions
  lib: notifier-error-inject: no need to check return value of debugfs_create functions
  swiotlb: no need to check return value of debugfs_create functions
  ceph: no need to check return value of debugfs_create functions
  sunrpc: no need to check return value of debugfs_create functions
  ubifs: no need to check return value of debugfs_create functions
  orangefs: no need to check return value of debugfs_create functions
  nfsd: no need to check return value of debugfs_create functions
  lib: 842: no need to check return value of debugfs_create functions
  debugfs: provide pr_fmt() macro
  debugfs: log errors when something goes wrong
  drivers: s390/cio: Fix compilation warning about const qualifiers
  drivers: Add generic helper to match by of_node
  driver_find_device: Unify the match function with class_find_device()
  bus_find_device: Unify the match callback with class_find_device
  ...
2019-07-12 12:24:03 -07:00
Thomas Gleixner
b886d83c5b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:17 +02:00
Greg Kroah-Hartman
db0487abd6 arm: dump: no need to check return value of debugfs_create functions
When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-03 15:49:07 +02:00
Jinbum Park
a8e53c151f ARM: 8737/1: mm: dump: add checking for writable and executable
Page mappings with full RWX permissions are a security risk.
x86, arm64 has an option to walk the page tables
and dump any bad pages.

(1404d6f13e
("arm64: dump: Add checking for writable and exectuable pages"))
Add a similar implementation for arm.

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-01-21 15:32:20 +00:00
Jinbum Park
d02ca6d76b ARM: 8736/1: mm: dump: make the page table dumping seq_file
This patch makes the page table dumping seq_file optional.
It makes the page table dumping code usable for other cases.

This patch refers below commit of arm64.
(ae5d1cf358
("arm64: dump: Make the page table dumping seq_file optional"))

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-01-21 15:32:18 +00:00
Jinbum Park
4fb69cc456 ARM: 8735/1: mm: dump: make page table dumping reusable
This patch refactors the arm page table dumping code,
so multiple tables may be registered with the framework.

This patch refers below commits of arm64.
(4674fdb9f1 ("arm64: mm: dump: make page table dumping reusable"))
(4ddb9bf833 ("arm64: dump: Make ptdump debugfs a separate option"))

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-01-21 15:32:17 +00:00
Philip Derrin
3b0c0c922f ARM: 8721/1: mm: dump: check hardware RO bit for LPAE
When CONFIG_ARM_LPAE is set, the PMD dump relies on the software
read-only bit to determine whether a page is writable. This
concealed a bug which left the kernel text section writable
(AP2=0) while marked read-only in the software bit.

In a kernel with the AP2 bug, the dump looks like this:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M ro x  SHD
    0xc0600000-0xc0800000           2M ro NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

The fix is to check that the software and hardware bits are both
set before displaying "ro". The dump then shows the true perms:

    ---[ Kernel Mapping ]---
    0xc0000000-0xc0200000           2M RW NX SHD
    0xc0200000-0xc0600000           4M RW x  SHD
    0xc0600000-0xc0800000           2M RW NX SHD
    0xc0800000-0xc4800000          64M RW NX SHD

Fixes: ded9477984 ("ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE")
Signed-off-by: Philip Derrin <philip@cog.systems>
Tested-by: Neil Dick <neil@cog.systems>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-11-21 15:10:07 +00:00
Kees Cook
dd59f974bd ARM: 8666/1: mm: dump: Add domain to output
This adds the memory domain (on non-LPAE) to the PMD and PTE dumps. This
isn't in the regular PMD bits because I couldn't find a clean way to
fall back to retain some of the PMD bits when reporting PTE. So this is
special-cased currently.

New output example:

  ---[ Modules ]---
  0x7f000000-0x7f001000       4K KERNEL      ro x  SHD MEM/CACHED/WBWA
  0x7f001000-0x7f002000       4K KERNEL      ro NX SHD MEM/CACHED/WBWA
  0x7f002000-0x7f004000       8K KERNEL      RW NX SHD MEM/CACHED/WBWA
  ---[ Kernel Mapping ]---
  0x80000000-0x80100000       1M KERNEL      RW NX SHD
  0x80100000-0x80800000       7M KERNEL      ro x  SHD
  0x80800000-0x80b00000       3M KERNEL      ro NX SHD
  0x80b00000-0xa0000000     501M KERNEL      RW NX SHD
  ...
  ---[ Vectors ]---
  0xffff0000-0xffff1000       4K VECTORS USR ro x  SHD MEM/CACHED/WBWA
  0xffff1000-0xffff2000       4K VECTORS     ro x  SHD MEM/CACHED/WBWA

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-03-29 17:39:17 +01:00
Afzal Mohammed
d2ca5f2491 ARM: 8646/1: mmu: decouple VECTORS_BASE from Kconfig
For MMU configurations, VECTORS_BASE is always 0xffff0000, a macro
definition will suffice.

For no-MMU, exception base address is dynamically determined in
subsequent patches. To preserve bisectability, now make the
macro applicable for no-MMU scenario too.

Thanks to 0-DAY kernel test infrastructure that found the
bisectability issue. This macro will be restricted to MMU case upon
dynamically determining exception base address for no-MMU.

Once exception address is handled dynamically for no-MMU,
VECTORS_BASE can be removed from Kconfig.

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2017-02-28 11:06:12 +00:00
Mark Rutland
cca547e9aa ARM: 8249/1: mm: dump: don't skip regions
Currently the arm page table dumping code starts dumping page tables
from USER_PGTABLES_CEILING. This is unnecessary for skipping any entries
related to userspace as the swapper_pg_dir does not contain such
entries, and results in a couple of unfortuante side effects.

Firstly, any kernel mappings which might exist below
USER_PGTABLES_CEILING will not be accounted in the dump output. This
masks any entries erroneously created below this address.

Secondly, if the final page table entry walked is part of a valid
mapping the page table dumping code will not log the region this entry
is part of, as the final note_page call in walk_pgd will trigger an
early return when 0 < USER_PGTABLES_CEILING. Luckily this isn't seen on
contemporary systems as they typically don't have enough RAM to extend
the linear mapping right to the end of the address space.

Due to the way addr is constructed in the walk_* functions, it can never
be less than USER_PGTABLES_CEILING when walking the page tables, so it
is not necessary to avoid dereferencing invalid table addresses. The
existing checks for st->current_prot and st->marker[1].start_address are
sufficient to ensure we will not print and/or dereference garbage when
trying to log information.

This patch removes both problematic uses of USER_PGTABLES_CEILING from
the arm page table dumping code, preventing both of these issues. We
will now report any low mappings, and the final note_page call will not
return early, ensuring all regions are logged.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-01-07 20:33:33 +00:00
Steven Capper
ded9477984 ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE
For LPAE, we have the following means for encoding writable or dirty
ptes:
                              L_PTE_DIRTY       L_PTE_RDONLY
    !pte_dirty && !pte_write        0               1
    !pte_dirty && pte_write         0               1
    pte_dirty && !pte_write         1               1
    pte_dirty && pte_write          1               0

So we can't distinguish between writeable clean ptes and read only
ptes. This can cause problems with ptes being incorrectly flagged as
read only when they are writeable but not dirty.

This patch renumbers L_PTE_RDONLY from AP[2] to a software bit #58,
and adds additional logic to set AP[2] whenever the pte is read only
or not dirty. That way we can distinguish between clean writeable ptes
and read only ptes.

HugeTLB pages will use this new logic automatically.

We need to add some logic to Transparent HugePages to ensure that they
correctly interpret the revised pgprot permissions (L_PTE_RDONLY has
moved and no longer matches PMD_SECT_AP2). In the process of revising
THP, the names of the PMD software bits have been prefixed with L_ to
make them easier to distinguish from their hardware bit counterparts.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-24 14:27:08 +01:00
Kees Cook
fff00db852 ARM: 8014/1: mm: fix reporting of read-only PMD bits
On non-LPAE ARMv6+, read-only PMD bits are defined with the combination
"PMD_SECT_APX | PMD_SECT_AP_WRITE". Adjusted the bit masks to correctly
report this.

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-04-07 12:10:01 +01:00
Kees Cook
cd91b2fecf ARM: 7963/1: mm: report both sections from PMD
On 2-level page table systems, the PMD has 2 section entries. Report
these, otherwise ARM_PTDUMP will miss reporting permission changes on
odd section boundaries.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-02-18 19:41:26 +00:00
Russell King
1fd15b879d ARM: add support to dump the kernel page tables
This patch allows the kernel page tables to be dumped via a debugfs file,
allowing kernel developers to check the layout of the kernel page tables
and the verify the various permissions and type settings.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-12-11 09:53:13 +00:00