Граф коммитов

148 Коммитов

Автор SHA1 Сообщение Дата
Linus Torvalds 93e95fa574 Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull siginfo updates from Eric Biederman:
 "This set of changes close the known issues with setting si_code to an
  invalid value, and with not fully initializing struct siginfo. There
  remains work to do on nds32, arc, unicore32, powerpc, arm, arm64, ia64
  and x86 to get the code that generates siginfo into a simpler and more
  maintainable state. Most of that work involves refactoring the signal
  handling code and thus careful code review.

  Also not included is the work to shrink the in kernel version of
  struct siginfo. That depends on getting the number of places that
  directly manipulate struct siginfo under control, as it requires the
  introduction of struct kernel_siginfo for the in kernel things.

  Overall this set of changes looks like it is making good progress, and
  with a little luck I will be wrapping up the siginfo work next
  development cycle"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
  signal/sh: Stop gcc warning about an impossible case in do_divide_error
  signal/mips: Report FPE_FLTUNK for undiagnosed floating point exceptions
  signal/um: More carefully relay signals in relay_signal.
  signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}
  signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code
  signal/signalfd: Add support for SIGSYS
  signal/signalfd: Remove __put_user from signalfd_copyinfo
  signal/xtensa: Use force_sig_fault where appropriate
  signal/xtensa: Consistenly use SIGBUS in do_unaligned_user
  signal/um: Use force_sig_fault where appropriate
  signal/sparc: Use force_sig_fault where appropriate
  signal/sparc: Use send_sig_fault where appropriate
  signal/sh: Use force_sig_fault where appropriate
  signal/s390: Use force_sig_fault where appropriate
  signal/riscv: Replace do_trap_siginfo with force_sig_fault
  signal/riscv: Use force_sig_fault where appropriate
  signal/parisc: Use force_sig_fault where appropriate
  signal/parisc: Use force_sig_mceerr where appropriate
  signal/openrisc: Use force_sig_fault where appropriate
  signal/nios2: Use force_sig_fault where appropriate
  ...
2018-06-04 15:23:48 -07:00
Masami Hiramatsu eb0146daef ARM: 8771/1: kprobes: Prohibit kprobes on do_undefinstr
Prohibit kprobes on do_undefinstr because kprobes on
arm is implemented by undefined instruction. This means
if we probe do_undefinstr(), it can cause infinit
recursive exception.

Fixes: 24ba613c9d ("ARM kprobes: core code")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-05-19 11:35:56 +01:00
Eric W. Biederman 3eb0f5193b signal: Ensure every siginfo we send has all bits initialized
Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-04-25 10:40:51 -05:00
Linus Torvalds 367b0df173 Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:

 - StrongARM SA1111 updates to modernise and remove cruft

 - Add StrongARM gpio drivers for board GPIOs

 - Verify size of zImage is what we expect to avoid issues with
   appended DTB

 - nommu updates from Vladimir Murzin

 - page table read-write-execute checking from Jinbum Park

 - Broadcom Brahma-B15 cache updates from Florian Fainelli

 - Avoid failure with kprobes test caused by inappropriately
   placed kprobes

 - Remove __memzero optimisation (which was incorrectly being
   used directly by some drivers)

* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits)
  ARM: 8745/1: get rid of __memzero()
  ARM: 8744/1: don't discard memblock for kexec
  ARM: 8743/1: bL_switcher: add MODULE_LICENSE tag
  ARM: 8742/1: Always use REFCOUNT_FULL
  ARM: 8741/1: B15: fix unused label warnings
  ARM: 8740/1: NOMMU: Make sure we do not hold stale data in mem[] array
  ARM: 8739/1: NOMMU: Setup VBAR/Hivecs for secondaries cores
  ARM: 8738/1: Disable CONFIG_DEBUG_VIRTUAL for NOMMU
  ARM: 8737/1: mm: dump: add checking for writable and executable
  ARM: 8736/1: mm: dump: make the page table dumping seq_file
  ARM: 8735/1: mm: dump: make page table dumping reusable
  ARM: sa1100/neponset: add GPIO drivers for control and modem registers
  ARM: sa1100/assabet: add BCR/BSR GPIO driver
  ARM: 8734/1: mm: idmap: Mark variables as ro_after_init
  ARM: 8733/1: hw_breakpoint: Mark variables as __ro_after_init
  ARM: 8732/1: NOMMU: Allow userspace to access background MPU region
  ARM: 8727/1: MAINTAINERS: Update brcmstb entries to cover B15 code
  ARM: 8728/1: B15: Register reboot notifier for KEXEC
  ARM: 8730/1: B15: Add suspend/resume hooks
  ARM: 8726/1: B15: Add CPU hotplug awareness
  ...
2018-02-02 09:50:51 -08:00
Andrew Morton dc8635b78c kernel/exit.c: export abort() to modules
gcc -fisolate-erroneous-paths-dereference can generate calls to abort()
from modular code too.

[arnd@arndb.de: drop duplicate exports of abort()]
  Link: http://lkml.kernel.org/r/20180102103311.706364-1-arnd@arndb.de
Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-04 16:45:09 -08:00
Russell King c608906165 ARM: probes: avoid adding kprobes to sensitive kernel-entry/exit code
Avoid adding kprobes to any of the kernel entry/exit or startup
assembly code, or code in the identity-mapped region.  This code does
not conform to the standard C conventions, which means that the
expectations of the kprobes code is not forfilled.

Placing kprobes at some of these locations results in the kernel trying
to return to userspace addresses while retaining the CPU in kernel mode.

Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-12-17 22:14:21 +00:00
Russell King 02196144a0 Merge branch 'devel-stable' into for-next 2017-11-08 19:42:47 +00:00
Mark Rutland b9dd05c700 ARM: 8720/1: ensure dump_instr() checks addr_limit
When CONFIG_DEBUG_USER is enabled, it's possible for a user to
deliberately trigger dump_instr() with a chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

So that we can use the same code to dump user instructions and kernel
instructions, the common dumping code is factored out to __dump_instr(),
with the fs manipulated appropriately in dump_instr() around calls to
this.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-11-06 12:00:38 +00:00
Nicolas Pitre 8fcd6c45f5 ARM: implement get_tls syscall
When there is no dedicated register to hold the tp value and no MMU
to provide a fixed address kuser helper entry point, all that is
left as fallback is a syscall.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Mickael GUENE <mickael.guene@st.com>
Tested-by: Vincent Abriou <vincent.abriou@st.com>
Tested-by: Andras Szemzo <szemzo.andras@gmail.com>
2017-09-10 19:31:46 -04:00
Ingo Molnar 68db0cf106 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:36 +01:00
Ingo Molnar b17b01533b sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:34 +01:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Russell King 24c66dfd56 ARM: fix backtrace
Recent kernels have changed their behaviour to be more inconsistent
when handling printk continuations.  With todays kernels, the output
looks sane on the console, but dmesg splits individual printk()s which
do not have the KERN_CONT prefix into separate lines.

Since the assembly code is not trivial to add the KERN_CONT, and we
ideally want to avoid using KERN_CONT (as multiple printk()s can race
between different threads), convert the assembly dumping the register
values to C code, and have the C code build the output a line at a
time before dumping to the console.

This avoids the KERN_CONT issue, and also avoids situations where the
output is intermixed with other console activity.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2016-11-15 15:25:39 +00:00
Russell King db695c0509 ARM: remove user cmpxchg syscall
Mark Brand reports that a NEEDS_SYSCALL_FOR_CMPXCHG enabled kernel would
open a security hole in the ghost syscall used to implement cmpxchg, as
it fails to validate the user pointer.

However, in order for this option to be enabled, you'd need to be
building a pre-ARMv6 kernel with SMP support.  There is only one system
known which fits that, which is an early ARM SMP FPGA implementation
based on the ARM926T.

In any case, the Kconfig does not allow SMP to be enabled for pre-ARMv6
systems.

Moreover, even if NEEDS_SYSCALL_FOR_CMPXCHG were to be enabled, the
kernel would not build as __ARM_NR_cmpxchg64 is not defined.

The simple answer is to remove the buggy code.

Reported-by: Mark Brand <markbrand@google.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-10-03 16:36:45 +01:00
Russell King 3c2aed5b28 ARM: domains: get rid of manager mode for user domain
Since we switched to early trap initialisation in 94e5a85b3b
("ARM: earlier initialization of vectors page") we haven't been writing
directly to the vectors page, and so there's no need for this domain
to be in manager mode.  Switch it to client mode.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-08-21 13:55:52 +01:00
Russell King 31cd08c3a1 ARM: remove __bad_xchg definition
We want link errors if xchg() is called for a variable size we do not
support.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-02 09:58:19 +01:00
Richard Weinberger a4980448ed arm: Remove signal translation and exec_domain
As execution domain support is gone we can remove
signal translation from the signal code and remove
exec_domain from thread_info.

Signed-off-by: Richard Weinberger <richard@nod.at>
2015-04-12 20:58:24 +02:00
Russell King fbe4dd088f Merge branches 'fixes', 'misc', 'pm' and 'sa1100' into for-next 2014-12-05 16:30:47 +00:00
Vladimir Murzin 3f4aa45cee ARM: 8226/1: cacheflush: get rid of restarting block
We cannot restart cacheflush safely if a process provides user-defined
signal handler and signal is pending. In this case -EINTR is returned
and it is expected that process re-invokes syscall. However, there are
a few problems with that:
 * looks like nobody bothers checking return value from cacheflush
 * but if it did, we don't provide the restart address for that, so the
   process has to use the same range again
 * ...and again, what might lead to looping forever

So, remove cacheflush restarting code and terminate cache flushing
as early as fatal signal is pending.

Cc: stable@vger.kernel.org # 3.12+
Reported-by: Chanho Min <chanho.min@lge.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-27 15:55:35 +00:00
Russell King 4ed89f2228 ARM: convert printk(KERN_* to pr_*
Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.

Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-21 15:24:50 +00:00
Russell King d5d1689224 Merge branches 'fiq' (early part), 'fixes', 'l2c' (early part) and 'misc' into for-next 2014-10-02 21:47:02 +01:00
Russell King 3467e765a5 ARM: remove unused do_unexp_fiq() function
do_unexp_fiq() has never been called by any code in the last 10 years,
it's about time it was removed!

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-18 00:35:43 +01:00
Daniel Thompson c0e7f7ee71 ARM: 8150/3: fiq: Replace default FIQ handler
This patch introduces a new default FIQ handler that is structured in a
similar way to the existing ARM exception handler and result in the FIQ
being handled by C code running on the SVC stack (despite this code run
in the FIQ handler is subject to severe limitations with respect to
locking making normal interaction with the kernel impossible).

This default handler allows concepts that on x86 would be handled using
NMIs to be realized on ARM.

Credit:

    This patch is a near complete re-write of a patch originally
    provided by Anton Vorontsov. Today only a couple of small fragments
    survive, however without Anton's work to build from this patch would
    not exist. Thanks also to Russell King for spoonfeeding me a variety
    of fixes during the review cycle.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-18 00:35:18 +01:00
Nathan Lynch fbfb872f5f ARM: 8148/1: flush TLS and thumbee register state during exec
The TPIDRURO and TPIDRURW registers need to be flushed during exec;
otherwise TLS information is potentially leaked.  TPIDRURO in
particular needs careful treatment.  Since flush_thread basically
needs the same code used to set the TLS in arm_syscall, pull that into
a common set_tls helper in tls.h and use it in both places.

Similarly, TEEHBR needs to be cleared during exec as well.  Clearing
its save slot in thread_info isn't right as there is no guarantee
that a thread switch will occur before the new program runs.  Just
setting the register directly is sufficient.

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-16 16:09:32 +01:00
Nikolay Borisov 49432d4acf ARM: 8074/1: traps: Make use of the frame_pointer macro
Use the newly-introduced frame_pointer macro to extract
the correct FP based on whether we are in THUMB2 mode or not.

Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-07-18 12:29:18 +01:00
Russell King b5b6b5f544 Dump the registers on undefined instruction userspace faults
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-04-11 14:48:39 +01:00
Russell King 6f14d778c1 Merge branches 'amba', 'fixes', 'kees', 'misc' and 'unstable/sa11x0' into for-next 2014-01-21 21:26:33 +00:00
Taras Kondratiuk d6cd989477 ARM: 7939/1: traps: fix opcode endianness when read from user memory
Currently code has an inverted logic: opcode from user memory
is swapped to a proper endianness only in case of read error.
While normally opcode should be swapped only if it was read
correctly from user memory.

Reviewed-by: Victor Kamensky <victor.kamensky@linaro.org>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-01-11 12:06:59 +00:00
Russell King 29c350bf28 ARM: fix "bad mode in ... handler" message for undefined instructions
The array was missing the final entry for the undefined instruction
exception handler; this commit adds it.

Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-01-05 14:00:00 +00:00
Russell King ef41b5c924 ARM: make kernel oops easier to read
We don't need the offset for the first function name in each backtrace
entry; this needlessly consumes screen space.  This is virtually always
the first or second instruction in the called function.

Also, recognise stmfd instructions which include r10 as a valid stack
saving instruction, and when dumping the registers, dump six registers
per line rather than five, and fix the wrapping.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-12-29 12:32:30 +00:00
Jon Medhurst b31459adea ARM: 7917/1: cacheflush: correctly limit range of memory region being flushed
The __do_cache_op function operates with a 'chunk' size of one page
but fails to limit the size of the final chunk so as to not exceed
the specified memory region. Fix this.

Cc: <stable@vger.kernel.org>
Reported-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-12-09 23:24:35 +00:00
Olof Johansson 5761704a41 ARM: 7892/1: Fix warning for V7M builds
Fixes a harmless warning when building for V7M (!MMU):
 arch/arm/kernel/traps.c:859:123: warning: 'kuser_init' defined but not used [-Wunused-function]

By making the stub static inline instead of just static.

Fixes: f6f91b0d9f ('ARM: allow kuser helpers to be removed from the vector page')

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-11-19 00:41:03 +00:00
Ben Dooks 63328070ef ARM: Correct BUG() assembly to ensure it is endian-agnostic
Currently BUG() uses .word or .hword to create the necessary illegal
instructions. However if we are building BE8 then these get swapped
by the linker into different illegal instructions in the text. This
means that the BUG() macro does not get trapped properly.

Change to using <asm/opcodes.h> to provide the necessary ARM instruction
building as we cannot rely on gcc/gas having the `.inst` instructions
which where added to try and resolve this issue (reported by Dave Martin
<Dave.Martin@arm.com>).

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
2013-10-19 20:46:35 +01:00
Ben Dooks a79a0cb1d3 ARM: traps: use <asm/opcodes.h> to get correct instruction order
The trap handler needs to take into account the endian configuration of
the system when loading instructions. Use <asm/opcodes.h> to provide the
necessary conversion functions.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2013-10-19 20:46:34 +01:00
Russell King 5cc91e0460 Merge branch 'for-rmk/cacheflush-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable 2013-08-28 18:38:40 +01:00
Will Deacon 97c72d89ce ARM: cacheflush: don't bother rounding to nearest vma
do_cache_op finds the lowest VMA contained in the specified address
range and rounds the range to cover only the mapped addresses.

Since commit 4542b6a0fa ("ARM: 7365/1: drop unused parameter from
flush_cache_user_range") the VMA is not used for anything else in this
code and seeing as the low-level cache flushing routines return -EFAULT
if the address is not valid, there is no need for this range truncation.

This patch removes the VMA handling code from the cacheflushing syscall.

Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-08-20 11:54:55 +01:00
Will Deacon 28256d6127 ARM: cacheflush: split user cache-flushing into interruptible chunks
Flushing a large, non-faulting VMA from userspace can potentially result
in a long time spent flushing the cache line-by-line without preemption
occurring (in the case of CONFIG_PREEMPT=n).

Whilst this doesn't affect the stability of the system, it can certainly
affect the responsiveness and CPU availability for other tasks.

This patch splits up the user cacheflush code so that it flushes in
chunks of a page. After each chunk has been flushed, we may reschedule
if appropriate and, before processing the next chunk, we allow any
pending signals to be handled before resuming from where we left off.

Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-08-20 11:54:53 +01:00
Russell King 48be69a026 ARM: move signal handlers into a vdso-like page
Move the signal handlers into a VDSO page rather than keeping them in
the vectors page.  This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks.  The new
VDSO page is also poisoned in the same way as the vector page.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-08-01 14:31:56 +01:00
Russell King f6f91b0d9f ARM: allow kuser helpers to be removed from the vector page
Provide a kernel configuration option to allow the kernel user helpers
to be removed from the vector page, thereby preventing their use with
ROP (return orientated programming) attacks.  This option is only
visible for CPU architectures which natively support all the operations
which kernel user helpers would normally provide, and must be enabled
with caution.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 22:01:48 +01:00
Russell King 19accfd373 ARM: move vector stubs
Move the machine vector stubs into the page above the vector page,
which we can prevent from being visible to userspace.  Also move
the reset stub, and place the swi vector at a location that the
'ldr' can get to it.

This hides pointers into the kernel which could give valuable
information to attackers, and reduces the number of exploitable
instructions at a fixed address.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:31:36 +01:00
Russell King f928d4f2a8 ARM: poison the vectors page
Fill the empty regions of the vectors page with an exception generating
instruction.  This ensures that any inappropriate branch to the vector
page is appropriately trapped, rather than just encountering some code
to execute.  (The vectors page was filled with zero before, which
corresponds with the "andeq r0, r0, r0" instruction - a no-op.)

Cc: <stable@vger.kernel.org>
Acked-by Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-07-31 21:30:57 +01:00
Russell King 3c0c01ab74 Merge branch 'devel-stable' into for-next
Conflicts:
	arch/arm/Makefile
	arch/arm/include/asm/glue-proc.h
2013-06-29 11:44:43 +01:00
André Hentschel a4780adeef ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork
Since commit 6a1c53124a the user writeable TLS register was zeroed to
prevent it from being used as a covert channel between two tasks.

There are more and more applications coming to Windows RT,
Wine could support them, but mostly they expect to have
the thread environment block (TEB) in TPIDRURW.

This patch preserves that register per thread instead of clearing it.
Unlike the TPIDRURO, which is already switched, the TPIDRURW
can be updated from userspace so needs careful treatment in the case that we
modify TPIDRURW and call fork(). To avoid this we must always read
TPIDRURW in copy_thread.

Signed-off-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-06-24 15:21:59 +01:00
Russell King f150abe101 Merge branch 'for-next' of git://git.pengutronix.de/git/ukl/linux into devel-stable
Pull ARM-v7M support from Uwe Kleine-König:
"All but the last patch were in next since next-20130418 without issues.
The last patch fixes a problem in combination with

  8164f7a (ARM: 7680/1: Detect support for SDIV/UDIV from ISAR0 register)

which triggers a WARN_ON without an implemented read_cpuid_ext.

The branch merges fine into v3.10-rc1 and I'd be happy if you pulled it
for 3.11-rc1. The only missing piece to be able to run a Cortex-M3 is
the irqchip driver that will go in via Thomas Gleixner and platform
specific stuff."
2013-05-22 10:52:24 +01:00
Tejun Heo 196779b9b4 dump_stack: consolidate dump_stack() implementations and unify their behaviors
Both dump_stack() and show_stack() are currently implemented by each
architecture.  show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack().  On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.

The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().

There's no reason to require archs to implement two separate but mostly
identical functions.  It leads to unnecessary subtle information.

This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin.  Blackfin's
dump_stack() does something wonky that I don't understand.

Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information.  This is used
in blackfin.

This patch brings the following behavior changes.

* On some archs, an extra level in backtrace for show_stack() could be
  printed.  This is because the top frame was determined in
  dump_stack() on those archs while generic dump_stack() can't do that
  reliably.  It can be compensated by inlining dump_stack() but not
  sure whether that'd be necessary.

* Most archs didn't use to print debug info on dump_stack().  They do
  now.

An example WARN dump follows.

 WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
 Hardware name: empty
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
  0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
  ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
  0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
 Call Trace:
  [<ffffffff81c614dc>] dump_stack+0x19/0x1b
  [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
  [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8234a071>] init_workqueues+0x35/0x505
  ...

v2: CPU number added to the generic debug info as requested by s390
    folks and dropped the s390 specific dump_stack().  This loses %ksp
    from the debug message which the maintainers think isn't important
    enough to keep the s390-specific dump_stack() implementation.

    dump_stack_print_info() is moved to kernel/printk.c from
    lib/dump_stack.c.  Because linkage is per objecct file,
    dump_stack_print_info() living in the same lib file as generic
    dump_stack() means that archs which implement custom dump_stack()
    - at this point, only blackfin - can't use dump_stack_print_info()
    as that will bring in the generic version of dump_stack() too.  v1
    The v1 patch broke build on blackfin due to this issue.  The build
    breakage was reported by Fengguang Wu.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>	[s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org>		[hexagon bits]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 17:04:02 -07:00
Catalin Marinas 55bdd69411 ARM: Add base support for ARMv7-M
This patch adds the base support for the ARMv7-M
architecture. It consists of the corresponding arch/arm/mm/ files and
various #ifdef's around the kernel. Exception handling is implemented by
a subsequent patch.

[ukleinek: squash in some changes originating from commit

b5717ba (Cortex-M3: Add support for the Microcontroller Prototyping System)

from the v2.6.33-arm1 patch stack, port to post 3.6, drop zImage
support, drop reorganisation of pt_regs, assert CONFIG_CPU_V7M doesn't
leak into installed headers and a few cosmetic changes]

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Jonathan Austin <jonathan.austin@arm.com>
Tested-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2013-04-17 21:38:10 +02:00
Rusty Russell 373d4d0997 taint: add explicit flag to show whether lock dep is still OK.
Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-01-21 17:17:57 +10:30
Will Deacon 2b2040af0b ARM: 7526/1: traps: send SIGILL if get_user fails on undef handling path
get_user may fail to load from the provided __user address due to an
unhandled fault generated by the access.

In the case of the undefined instruction trap, this results in failure
to load the faulting instruction, in which case we should send SIGILL to
the task rather than continue with potentially uninitialised data.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-09-07 20:40:44 +01:00
Linus Torvalds 02a6ec6a24 Merge branch 'audit' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM audit/signal updates from Russell King:
 "ARM audit/signal handling updates from Al and Will.  This improves on
  the work Viro did last merge window, and sorts out some of the issues
  found with that work."

* 'audit' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace
  ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS
  ARM: 7473/1: deal with handlerless restarts without leaving the kernel
  ARM: 7472/1: pull all work_pending logics into C function
  ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline""
  ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""
2012-08-01 16:35:37 -07:00
Linus Torvalds 9a2533c3eb Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM fixes from Russell King:
 "This fixes various issues found during July"

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7479/1: mm: avoid NULL dereference when flushing gate_vma with VIVT caches
  ARM: Fix undefined instruction exception handling
  ARM: 7480/1: only call smp_send_stop() on SMP
  ARM: 7478/1: errata: extend workaround for erratum #720789
  ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP
  ARM: 7476/1: vfp: only clear vfp state for current cpu in vfp_pm_suspend
  ARM: 7468/1: ftrace: Trace function entry before updating index
  ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+
  ARM: 7466/1: disable interrupt before spinning endlessly
  ARM: 7465/1: Handle >4GB memory sizes in device tree and mem=size@start option
2012-08-01 16:30:45 -07:00