linux.git/arch/arm/kernel/traps.c, branch v3.11

ARM: move signal handlers into a vdso-like page

2013-08-01T13:31:56+00:00

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

ARM: allow kuser helpers to be removed from the vector page

2013-07-31T21:01:48+00:00

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: 
Acked-by: Nicolas Pitre 
Signed-off-by: Russell King

ARM: move vector stubs

2013-07-31T20:31:36+00:00

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: 
Acked-by: Nicolas Pitre 
Signed-off-by: Russell King

ARM: poison the vectors page

2013-07-31T20:30:57+00:00

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: 
Acked-by Nicolas Pitre 
Signed-off-by: Russell King

Merge branch 'devel-stable' into for-next

2013-06-29T10:44:43+00:00

Conflicts:
	arch/arm/Makefile
	arch/arm/include/asm/glue-proc.h

ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork

2013-06-24T14:21:59+00:00

Since commit 6a1c53124aa1 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 
Signed-off-by: Will Deacon 
Signed-off-by: Jonathan Austin 
Signed-off-by: Russell King

Merge branch 'for-next' of git://git.pengutronix.de/git/ukl/linux into devel-stable

2013-05-22T09:52:24+00:00

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."

dump_stack: consolidate dump_stack() implementations and unify their behaviors

2013-05-01T00:04:02+00:00

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:
  [] dump_stack+0x19/0x1b
  [] warn_slowpath_common+0x7f/0xc0
  [] warn_slowpath_null+0x1a/0x20
  [] 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 
Acked-by: David S. Miller 
Acked-by: Vineet Gupta 
Acked-by: Jesper Nilsson 
Acked-by: Vineet Gupta 
Acked-by: Martin Schwidefsky 	[s390 bits]
Cc: Heiko Carstens 
Cc: Mike Frysinger 
Cc: Fengguang Wu 
Cc: Bjorn Helgaas 
Cc: Sam Ravnborg 
Acked-by: Richard Kuo 		[hexagon bits]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ARM: Add base support for ARMv7-M

2013-04-17T19:38:10+00:00

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 
Reviewed-by: Jonathan Austin 
Tested-by: Jonathan Austin 
Signed-off-by: Uwe Kleine-König

taint: add explicit flag to show whether lock dep is still OK.

2013-01-21T06:47:57+00:00

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