Commit 0a8ea52c ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API
feature") inadvertently removed the arch/arm prototype instead of the
arm64 one introduced by the original patch. There should not be any
bisection issues since this function is not called from anywhere else
(it could as well be removed from arch/arm at some point).

Fixes: 0a8ea52c ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature")
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64, including supporting
functions and defines.
Signed-off-by: NDavid A. Long <dave.long@linaro.org>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: Remove unused functions]
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

When we enter an exception, the current address limit should not apply
to the exception context: if the exception context wishes to access
kernel space via the user accessors (eg, perf code), it must explicitly
request such access.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Get rid of the horrible "*(unsigned int *)(regs + 1)" to get at the
parent context domain access register value, instead using the newly
introduced svc_pt_regs structure.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Since the privileged mode pt_regs are an extended version of the saved
userland pt_regs, introduce a new svc_pt_regs structure to describe this
layout.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Use the global current_stack_pointer to calculate the end of the stack for
current_pt_regs()
Signed-off-by: NBehan Webster <behanw@converseincode.com>
Reviewed-by: NMark Charlebois <charlebm@gmail.com>
Reviewed-by: NJan-Simon Möller <dl9pf@gmx.de>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Currently there are numerous places where "struct pt_regs" are used to
populate "struct stackframe", however all of those location do not
consider the situation where the kernel might be compiled in THUMB2
mode, in which case the framepointer member of pt_regs become ARM_r7
instead of ARM_fp (r11). Document this idiosyncracy in the
definition of "struct stackframe"

The easiest solution is to introduce a new function (in the spirit of
https://groups.google.com/forum/#!topic/linux.kernel/dA2YuUcSpZ4)
which would hide the complexity of initializing the stackframe struct
from pt_regs.

Also implement a macro frame_pointer(regs) that would return the correct
register so that we can use it in cases where we just require the frame
pointer and not a whole struct stackframe
Signed-off-by: NNikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NRobert Richter <rric@kernel.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Using Rabin Vincent's ARM uprobes patches as a base, enable uprobes
support on ARM.

Caveats:

 - Thumb is not supported
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NDavid A. Long <dave.long@linaro.org>

The definition of isa_mode hardcodes the values to shift PSR_J_BIT and
PSR_T_BIT to move them to bits 1 and 0 respectively. Instead use __ffs to
calculate the shift from the #define already used for masking.

This is relevant on v7-M as there PSR_T_BIT is 0x01000000 instead of
0x00000020 for V7-[AR] and earlier. Because of that isa_mode produced
values >= 0x80000 which are unsuitable to index into isa_modes[4] there
and so made __show_regs read from undefined memory which resulted in
hangs and crashes.

Moreover isa_mode is wrong for v7-M even after this robustness fix as
there is no J-bit in the PSR register. So hardcode isa_mode to "Thumb"
for v7-M.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>

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: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NJonathan Austin <jonathan.austin@arm.com>
Tested-by: NJonathan Austin <jonathan.austin@arm.com>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

... no need to read current_thread_info()->task only to
feed it to task_thread_page() immediately afterwards.
Moreover, not using current_thread_info() at all ends
up with better assembler - we need a location very close
to the top of kernel stack page and it's actually better
to do or with 0x1fff, followed be subtracting a small
constant than and with ~0x1fff, followed by adding a large
one.  Both & and | would be a couple of insns (mvn lsr/mvn lsl
for |, a pair of bic for &), but the following addition
would cost a pair of add while the subtraction ends up
as a single sub.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch does two things:

  * Ensure that asynchronous aborts are masked at kernel entry.
    The bootloader should be masking these anyway, but this reduces
    the damage window just in case it doesn't.

  * Enter svc mode via exception return to ensure that CPU state is
    properly serialised.  This does not matter when switching from
    an ordinary privileged mode ("PL1" modes in ARMv7-AR rev C
    parlance), but it potentially does matter when switching from a
    another privileged mode such as hyp mode.

This should allow the kernel to boot safely either from svc mode or
hyp mode, even if no support for use of the ARM Virtualization
Extensions is built into the kernel.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Add calls to tracehook_report_syscall_{entry,exit} and tracehook_signal_handler
Signed-off-by: NSteven Walter <stevenrwalter@gmail.com>
Signed-off-by: NWade Farnsworth <wade_farnsworth@mentor.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch provides functionality to audit system call events on the
ARM platform. The implementation was based off the structure of the
MIPS platform and information in this
(http://lists.fedoraproject.org/pipermail/arm/2009-October/000382.html)
mailing list thread. The required audit_syscall_exit and
audit_syscall_entry checks were added to ptrace using the standard
registers for system call values (r0 through r3). A thread information
flag was added for auditing (TIF_SYSCALL_AUDIT) and a meta-flag was
added (_TIF_SYSCALL_WORK) to simplify modifications to the syscall
entry/exit. Now, if either the TRACE flag is set or the AUDIT flag is
set, the syscall_trace function will be executed. The prober changes
were made to Kconfig to allow CONFIG_AUDITSYSCALL to be enabled.

Due to platform availability limitations, this patch was only tested
on the Android platform running the modified "android-goldfish-2.6.29"
kernel. A test compile was performed using Code Sourcery's
cross-compilation toolset and the current linux-3.0 stable kernel. The
changes compile without error. I'm hoping, due to the simple modifications,
the patch is "obviously correct".
Signed-off-by: NNathaniel Husted <nhusted@gmail.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

APSR_MASK can be used to extract the APSR bits from the CPSR. The
comment for these definitions is also changed because it was inaccurate
as the existing defines didn't refer to any part of the APSR.
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>

This patch allows undef_hook's to be specified for 32-bit Thumb
instructions and also to be used for thumb kernel-side code.

32-bit Thumb instructions are specified in the form:
	((first_half << 16 ) | second_half)
which matches the layout used by the ARM ARM.

ptrace was handling 32-bit Thumb instructions by hooking the first
halfword and manually checking the second half. This method would be
broken by this patch so it is migrated to make use of the new Thumb-2
support.
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>

This patch migrates the implementation of the ptrace interface for
the core integer registers, legacy FPA registers and VFP registers
to use the regsets framework.

As an added bonus, all this stuff gets included in coredumps
at no extra cost.  Without this patch, coredumps contained no
VFP state.

Third-party extension register sets (iwmmx, crunch) are not migrated
by this patch, and continue to use the old implementation;
these should be migratable without much extra work.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Acked-by: NWill Deacon <Will.Deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

PTRACE_SINGLESTEP is a ptrace request designed to offer single-stepping
support to userspace when the underlying architecture has hardware
support for this operation.

On ARM, we set arch_has_single_step() to 1 and attempt to emulate hardware
single-stepping by disassembling the current instruction to determine the
next pc and placing a software breakpoint on that location.

Unfortunately this has the following problems:

1.) Only a subset of ARMv7 instructions are supported
2.) Thumb-2 is unsupported
3.) The code is not SMP safe

We could try to fix this code, but it turns out that because of the above
issues it is rarely used in practice.  GDB, for example, uses PTRACE_POKETEXT
and PTRACE_PEEKTEXT to manage breakpoints itself and does not require any
kernel assistance.

This patch removes the single-step emulation code from ptrace meaning that
the PTRACE_SINGLESTEP request will return -EIO on ARM. Portable code must
check the return value from a ptrace call and handle the failure gracefully.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

For debuggers to take advantage of the hw-breakpoint framework in the kernel,
it is necessary to expose the API calls via a ptrace interface.

This patch exposes the hardware breakpoints framework as a collection of
virtual registers, accesible using PTRACE_SETHBPREGS and PTRACE_GETHBPREGS
requests. The breakpoints are stored in the debug_info struct of the running
thread.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: S. Karthikeyan <informkarthik@gmail.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Reviewed-by: NArve Hjønnevåg <arve@android.com>
Acked-by: NDima Zavin <dima@android.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch enables the HAVE_REGS_AND_STACK_ACCESS_API option
for ARM which is required by the kprobe events tracer. Code based
on the PowerPC port.

Cc: Jean Pihet <jpihet@mvista.com>
Tested-by: NJamie Iles <jamie.iles@picochip.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT,
PTRACE_KILL and PTRACE_SINGLESTEP.  This implies defining
arch_has_single_step in <asm/ptrace.h> and implementing the
user_enable_single_step and user_disable_single_step functions, which also
causes the breakpoint information to be cleared on fork, which could be
considered a bug fix.

Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL which
it previously wasn't and the single stepping disable only happens if the
tracee process isn't a zombie yet, which is consistent with all
architectures using the modern ptrace code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make registers unsigned for kernel space. This is important for
example in the perf events where the PC is stored into a u64. We
don't want it sign extended so make the regs unsigned to prevent
casts throughout the kernel.
Signed-off-by: NJamie Iles <jamie.iles@picochip.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The patch below adds ARM ptrace functions to get the process load address.
This is required for useful userspace debugging on mmuless systems.  These
values are obtained by reading magic offsets with PTRACE_PEEKUSR, as on other
nommu targets. I picked arbitrary large values for the offsets.
Signed-off-by: NPaul Brook <paul@codesourcery.com>

Starting with ARMv6, the CPUs support the BE-8 variant of big-endian
(byte-invariant). This patch adds the core support:

- setting of the BE-8 mode via the CPSR.E register for both kernel and
  user threads
- big-endian page table walking
- REV used to rotate instructions read from memory during fault
  processing as they are still little-endian format
- Kconfig and Makefile support for BE-8. The --be8 option must be passed
  to the final linking stage to convert the instructions to
  little-endian
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

If a process is interrupted during an If-Then block and a signal is
invoked, the ITSTATE bits must be cleared otherwise the handler would
not run correctly.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Joseph S. Myers <joseph@codesourcery.com>

This patch adds ptrace support for setting and getting the VFP registers
using PTRACE_SETVFPREGS and PTRACE_GETVFPREGS. The user_vfp structure
defined in asm/user.h contains 32 double registers (to cover VFPv3 and
Neon hardware) and the FPSCR register.

Cc: Paul Brook <paul@codesourcery.com>
Cc: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

pc_pointer() was a function to mask the PC for 26-bit ARMs, which
we no longer support.  Remove it.
Signed-off-by: NRussell 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: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch contains the following cleanups for the asm/ptrace.h
userspace headers:

- include/asm-generic/Kbuild.asm already lists ptrace.h, remove
  the superfluous listings in the Kbuild files of the following
  architectures:
  - cris
  - frv
  - powerpc
  - x86
- don't expose function prototypes and macros to userspace:
  - arm
  - blackfin
  - cris
  - mn10300
  - parisc
- remove #ifdef CONFIG_'s around #define's:
  - blackfin
  - m68knommu
- sh: AFAIK __SH5__ should work in both kernel and userspace,
      no need to leak CONFIG_SUPERH64 to userspace
- xtensa: cosmetical change to remove empty
            #ifndef __ASSEMBLY__ #else #endif
          from the userspace headers

Not changed by this patch is the fact that the following architectures
have a different struct pt_regs depending on CONFIG_ variables:
- h8300
- m68knommu
- mips

This does not work in userspace.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NGrant Grundler <grundler@parisc-linux.org>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NChris Zankel <chris@zankel.net>
Acked-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When running Linux in non-secure mode (on ARM1176 for example),
depending on the CP15 secure configuration register, the CPSR.F bit
(6) might only be modified from the secure mode. However, the
valid_user_regs() function checks for this bit being cleared. With
commit a6c61e9d, a SIGSEGV is forced in handle_signal() if the user
registers are not considered valid.

The patch also ensures that the CPSR.A bit is cleared and the USR mode
is set if the CPU does not support the 26bit user mode.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The ARM show_regs() tombstone only partially decodes which ARM ISA was
executing at the time a fault occurred displaying either "(T)" for the
Thumb case or nothing at all for other cases.  This patch therefore
explicitly identifies which state the processor is in at the time of
a fault: ARM, Thumb, Jazelle or JazelleEE.
Signed-off-by: NGeorge G. Davis <gdavis@mvista.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add the kernel release and version information to the output of
show_regs/oops.  Add the CPU PSR register.  Avoid using printk
to output partial lines; always output a complete line.

Re-combine the "Control" and "Table + DAC" lines after nommu
separated them; we don't want to waste vertical screen space
needlessly.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

This patch makes it possible to get/set a task's Crunch state via
the ptrace(2) system call.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Patch from Nicolas Pitre

This is needed by strace to properly handle the tracing of some system
calls. It could be useful for other applications as well.

Based on an earlier patch from Daniel Jacobowitz.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NDaniel Jacobowitz <dan@debian.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

The ARM EABI says that the stack pointer has to be 64-bit aligned for
reasons already mentioned in patch #3101 when calling C functions.

We therefore must verify and adjust sp accordingly when taking an
exception from kernel mode since sp might not necessarily be 64-bit
aligned if the exception occurs in the middle of a kernel function.

If the exception occurs while in user mode then no sp fixup is needed as
long as sizeof(struct pt_regs) as well as any additional syscall data
stack space remain multiples of 8.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix show_regs() to provide a backtrace.  Provide a new __show_regs()
function which implements the common subset of show_regs() and die().
Add prototypes to asm-arm/system.h
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>