Граф коммитов

35 Коммитов

Автор SHA1 Сообщение Дата
Haibo Li fa3eeb638d ARM: 9295/1: unwind:fix unwind abort for uleb128 case
When unwind instruction is 0xb2,the subsequent instructions
are uleb128 bytes.
For now,it uses only the first uleb128 byte in code.

For vsp increments of 0x204~0x400,use one uleb128 byte like below:
0xc06a00e4 <unwind_test_work>: 0x80b27fac
  Compact model index: 0
  0xb2 0x7f vsp = vsp + 1024
  0xac      pop {r4, r5, r6, r7, r8, r14}

For vsp increments larger than 0x400,use two uleb128 bytes like below:
0xc06a00e4 <unwind_test_work>: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x01 vsp = vsp + 1032
  0xac      pop {r4, r5, r6, r7, r8, r14}
The unwind works well since the decoded uleb128 byte is also 0x81.

For vsp increments larger than 0x600,use two uleb128 bytes like below:
0xc06a00e4 <unwind_test_work>: @0xc0cc9e0c
  Compact model index: 1
  0xb2 0x81 0x02 vsp = vsp + 1544
  0xac      pop {r4, r5, r6, r7, r8, r14}
In this case,the decoded uleb128 result is 0x101(vsp=0x204+(0x101<<2)).
While the uleb128 used in code is 0x81(vsp=0x204+(0x81<<2)).
The unwind aborts at this frame since it gets incorrect vsp.

To fix this,add uleb128 decode to cover all the above case.

Signed-off-by: Haibo Li <haibo.li@mediatek.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2023-05-05 10:16:40 +01:00
Alex Sverdlin 4ab07fd3fb ARM: 9252/1: module: Teach unwinder about PLTs
"unwind: Index not found eef26358" warnings keep popping up on
CONFIG_ARM_MODULE_PLTS-enabled systems if the PC points to a PLT veneer.
Teach the unwinder how to deal with them, taking into account they don't
change state of the stack or register file except loading PC.

Link: https://lore.kernel.org/linux-arm-kernel/20200402153845.30985-1-kursad.oney@broadcom.com/

Tested-by: Kursad Oney <kursad.oney@broadcom.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-11-07 14:18:59 +00:00
Ard Biesheuvel f6b8e3526f ARM: unwind: only permit stack switch when unwinding call_with_stack()
Commit b6506981f8 ("ARM: unwind: support unwinding across multiple
stacks") updated the logic in the ARM unwinder to widen the bounds
within which SP is assumed to be valid, in order to allow the unwind to
traverse from the IRQ stack to the task stack. This is necessary, as
otherwise, unwinds started from the IRQ stack would terminate in the IRQ
exception handler, making stacktraces substantially less useful.

This turns out to be a mistake, as it breaks asynchronous unwinding
across exceptions, when the exception is taken before the stack frame is
consistent with the unwind info. For instance, in the following
backtrace:

  ...
   generic_handle_arch_irq from call_with_stack+0x18/0x20
   call_with_stack from __irq_svc+0x80/0x98
  Exception stack(0xc7093e20 to 0xc7093e68)
  3e20: b6a94a88 c7093ea0 00000008 00000000 c7093ea0 b7e127d0 00000051 c9220000
  3e40: b6a94a88 b6a94a88 00000004 0002b000 0036b570 c7093e70 c040ca2c c0994a90
  3e60: 20070013 ffffffff
   __irq_svc from __copy_to_user_std+0x20/0x378
  ...

we need to apply the following unwind directives:

  0xc099720c <__copy_to_user_std+0x1c>: @0xc295d1d4
    Compact model index: 1
    0x9b      vsp = r11
    0xb1 0x0d pop {r0, r2, r3}
    0x84 0x81 pop {r4, r11, r14}
    0xb0      finish

which tell us to switch to the frame pointer register R11 and proceed
with the unwind from that. However, having been interrupted 0x20 bytes
into the function:

  c09971f0 <__copy_to_user_std>:
  c09971f0:       e59f3350        ldr     r3, [pc, #848]
  c09971f4:       e243c001        sub     ip, r3, #1
  c09971f8:       e05cc000        subs    ip, ip, r0
  c09971fc:       228cc001        addcs   ip, ip, #1
  c0997200:       205cc002        subscs  ip, ip, r2
  c0997204:       33a00000        movcc   r0, #0
  c0997208:       e320f014        csdb
  c099720c:       e3a03000        mov     r3, #0
  c0997210:       e92d481d        push    {r0, r2, r3, r4, fp, lr}
  c0997214:       e1a0b00d        mov     fp, sp
  c0997218:       e2522004        subs    r2, r2, #4

the value for R11 recovered from the previous frame (__irq_svc) will be
a snapshot of its value before the exception was taken (0x0002b000),
which occurred at address __copy_to_user_std+0x20 (0xc0997210), when R11
had not been assigned its value yet.

This means we can never assume that the SP values recovered from the
stack or from the frame pointer are ever safe to use, given the need to
do asynchronous unwinding, and the only robust approach is to revert to
the previous approach, which is to derive bounds for SP based on the
initial value, and never update them.

We can make an exception, though: now that the IRQ stack switch is
guaranteed to occur in call_with_stack(), we can implement a special
case for this function, and use a different set of bounds based on the
knowledge that it will always unwind from R11 rather than SP. As
call_with_stack() is a hand-rolled assembly routine, this is guaranteed
to remain that way.

So let's do a partial revert of b6506981f8, and drop all manipulations
for sp_low and sp_high based on the information collected during the
unwind itself. To support call_with_stack(), set sp_low and sp_high
explicitly to values derived from R11 when we unwind that function.

The only downside is that, while unwinding an overflow of the vmap'ed
stack will work fine as before, we will no longer be able to produce a
backtrace that unwinds the overflow stack itself across the exception
that was raised due to the faulting access to the guard region. However,
this only affects exceptions caused by problems in the stack overflow
handling code itself, in which case the remaining backtrace is not that
relevant.

Fixes: b6506981f8 ("ARM: unwind: support unwinding across multiple stacks")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11 13:01:00 +00:00
Ard Biesheuvel bee4e1fdc3 ARM: Revert "unwind: dump exception stack from calling frame"
After simplifying the stack switch code in the IRQ exception handler by
deferring the actual stack switch to call_with_stack(), we no longer
need to special case the way we dump the exception stack, since it will
always be at the top of whichever stack was active when the exception
was taken.

So revert this special handling for the ARM unwinder.

This reverts commit 4ab6827081.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11 13:00:55 +00:00
Russell King (Oracle) c46c2c9b43 ARM: unwind: set frame.pc correctly for current-thread unwinding
When e.g. a WARN_ON() is encountered, we attempt to unwind the current
thread. To do this, we set frame.pc to unwind_backtrace, which means it
points at the beginning of the function. However, the rest of the state
is initialised from within the function, which means the function
prologue has already been run.

This can be confusing, and with a recent patch from Ard, can result in
the unwinder misbehaving if we want to be strict about the PC value.

If we correctly initialise the state so it is self-consistent (in other
words, set frame.pc to the location we are initialising it) then we
eliminate this confusion, and avoid possible future issues.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11 10:55:28 +00:00
Ard Biesheuvel 8167937647 ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses
Corentin reports that since commit 538b9265c0 ("ARM: unwind: track
location of LR value in stack frame"), numerous spurious warnings are
emitted into the kernel log:

  [    0.000000] unwind: Index not found c0f0c440
  [    0.000000] unwind: Index not found 00000000
  [    0.000000] unwind: Index not found c0f0c440
  [    0.000000] unwind: Index not found 00000000

This is due to the fact that the commit in question removes a check
whether the PC value in the unwound frame is actually a kernel text
address, on the assumption that such an address will not be associated
with valid unwind data to begin with, which is checked right after.

The reason for removing this check was that unwind_frame() will be
called by the ftrace graph tracer code, which means that it can no
longer be safely instrumented itself, or any code that it calls, as it
could cause infinite recursion.

In order to prevent the spurious diagnostics, let's add back the call to
kernel_text_address(), but this time, only call it if no unwind data
could be found for the address in question. This is more efficient for
the common successful case, and should avoid any unintended recursion,
considering that kernel_text_address() will only be called if no unwind
data was found.

Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Fixes: 538b9265c0 ("ARM: unwind: track location of LR value in stack frame")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-07 11:43:12 +00:00
Ard Biesheuvel 538b9265c0 ARM: unwind: track location of LR value in stack frame
The ftrace graph tracer needs to override the return address of an
instrumented function, in order to install a hook that gets invoked when
the function returns again.

Currently, we only support this when building for ARM using GCC with
frame pointers, as in this case, it is guaranteed that the function will
reload LR from [FP, #-4] in all cases, and we can simply pass that
address to the ftrace code.

In order to support this for configurations that rely on the EABI
unwinder, such as Thumb2 builds, make the unwinder keep track of the
address from which LR was unwound, permitting ftrace to make use of this
in a subsequent patch.

Drop the call to is_kernel_text_address(), which is problematic in terms
of ftrace recursion, given that it may be instrumented itself. The call
is redundant anyway, as no unwind directives will be found unless the PC
points to memory that is known to contain executable code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-02-09 09:13:43 +01:00
Ard Biesheuvel a1c510d0ad ARM: implement support for vmap'ed stacks
Wire up the generic support for managing task stack allocations via vmalloc,
and implement the entry code that detects whether we faulted because of a
stack overrun (or future stack overrun caused by pushing the pt_regs array)

While this adds a fair amount of tricky entry asm code, it should be
noted that it only adds a TST + branch to the svc_entry path. The code
implementing the non-trivial handling of the overflow stack is emitted
out-of-line into the .text section.

Since on ARM, we rely on do_translation_fault() to keep PMD level page
table entries that cover the vmalloc region up to date, we need to
ensure that we don't hit such a stale PMD entry when accessing the
stack. So we do a dummy read from the new stack while still running from
the old one on the context switch path, and bump the vmalloc_seq counter
when PMD level entries in the vmalloc range are modified, so that the MM
switch fetches the latest version of the entries.

Note that we need to increase the per-mode stack by 1 word, to gain some
space to stash a GPR until we know it is safe to touch the stack.
However, due to the cacheline alignment of the struct, this does not
actually increase the memory footprint of the struct stack array at all.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:33 +01:00
Ard Biesheuvel 532319b9c4 ARM: unwind: disregard unwind info before stack frame is set up
When unwinding the stack from a stack overflow, we are likely to start
from a stack push instruction, given that this is the most common way to
grow the stack for compiler emitted code. This push instruction rarely
appears anywhere else than at offset 0x0 of the function, and if it
doesn't, the compiler tends to split up the unwind annotations, given
that the stack frame layout is apparently not the same throughout the
function.

This means that, in the general case, if the frame's PC points at the
first instruction covered by a certain unwind entry, there is no way the
stack frame that the unwind entry describes could have been created yet,
and so we are still on the stack frame of the caller in that case. So
treat this as a special case, and return with the new PC taken from the
frame's LR, without applying the unwind transformations to the virtual
register set.

This permits us to unwind the call stack on stack overflow when the
overflow was caused by a stack push on function entry.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:32 +01:00
Ard Biesheuvel 4ab6827081 ARM: unwind: dump exception stack from calling frame
The existing code that dumps the contents of the pt_regs structure
passed to __entry routines does so while unwinding the callee frame, and
dereferences the stack pointer as a struct pt_regs*. This will no longer
work when we enable support for IRQ or overflow stacks, because the
struct pt_regs may live on the task stack, while we are executing from
another stack.

The unwinder has access to this information, but only while unwinding
the calling frame. So let's combine the exception stack dumping code
with the handling of the calling frame as well. By printing it before
dumping the caller/callee addresses, the output order is preserved.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Ard Biesheuvel b6506981f8 ARM: unwind: support unwinding across multiple stacks
Implement support in the unwinder for dealing with multiple stacks.
This will be needed once we add support for IRQ stacks, or for the
overflow stack used by the vmap'ed stacks code.

This involves tracking the unwind opcodes that either update the virtual
stack pointer from another virtual register, or perform an explicit
subtract on the virtual stack pointer, and updating the low and high
bounds that we use to sanitize the stack pointer accordingly.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Nick Desaulniers 331b9d02d7 ARM: 9026/1: unwind: remove old check for GCC <= 4.2
Since
commit 0bddd227f3 ("Documentation: update for gcc 4.9 requirement")
the minimum supported version of GCC is gcc-4.9. It's now safe to remove
this code.

Link: https://github.com/ClangBuiltLinux/linux/issues/427

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-12-08 10:13:59 +00:00
Linus Walleij d5d44e7e35 ARM: 9013/2: Disable KASan instrumentation for some code
Disable instrumentation for arch/arm/boot/compressed/*
since that code is executed before the kernel has even
set up its mappings and definately out of scope for
KASan.

Disable instrumentation of arch/arm/vdso/* because that code
is not linked with the kernel image, so the KASan management
code would fail to link.

Disable instrumentation of arch/arm/mm/physaddr.c. See commit
ec6d06efb0 ("arm64: Add support for CONFIG_DEBUG_VIRTUAL")
for more details.

Disable kasan check in the function unwind_pop_register because
it does not matter that kasan checks failed when unwind_pop_register()
reads the stack memory of a task.

Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org> # QEMU/KVM/mach-virt/LPAE/8G
Tested-by: Florian Fainelli <f.fainelli@gmail.com> # Brahma SoCs
Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de> # i.MX6Q
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Abbott Liu <liuwenliang@huawei.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-10-27 12:11:04 +00:00
Dmitry Safonov e8d7b73532 arm: add loglvl to unwind_backtrace()
Currently, the log-level of show_stack() depends on a platform
realization.  It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).

Furthermore, it forces the logic decision from user to an architecture
side.  In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.  And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers.  Also, it will consolidate
printings with headers.

Add log level argument to unwind_backtrace() as a preparation for
introducing show_stack_loglvl().

As a good side-effect arm_syscall() is now printing errors with the same
log level as the backtrace.

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-6-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:10 -07:00
Dmitry Safonov 5489ab50c2 arm/asm: add loglvl to c_backtrace()
Currently, the log-level of show_stack() depends on a platform
realization.  It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).

Furthermore, it forces the logic decision from user to an architecture
side.  In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.  And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers.  Also, it will consolidate
printings with headers.

Add log level argument to c_backtrace() as a preparation for introducing
show_stack_loglvl().

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-5-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:10 -07:00
Russell King 8d54a27593 ARM: allow unwinder to unwind recursive functions
Allow the unwinder to unwind recursive functions if the stack makes
progress, even if the PC is the same. This allows tracing through
recursive __switchdev_handle_port_attr_set() and similar.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-02-21 16:58:50 +00:00
Thomas Gleixner 4505153954 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333
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 version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 59 temple place suite 330 boston ma 02111
  1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:06 +02:00
Sebastian Andrzej Siewior 74ffe79ae5 ARM: 8840/1: use a raw_spinlock_t in unwind
Mostly unwind is done with irqs enabled however SLUB may call it with
irqs disabled while creating a new SLUB cache.

I had system freeze while loading a module which called
kmem_cache_create() on init. That means SLUB's __slab_alloc() disabled
interrupts and then

->new_slab_objects()
 ->new_slab()
  ->setup_object()
   ->setup_object_debug()
    ->init_tracking()
     ->set_track()
      ->save_stack_trace()
       ->save_stack_trace_tsk()
        ->walk_stackframe()
         ->unwind_frame()
          ->unwind_find_idx()
           =>spin_lock_irqsave(&unwind_lock);

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2019-02-26 11:24:51 +00:00
Behan Webster 0bf4954f24 ARM: 8176/1: Use current_stack_pointer in unwind_backtrace
Use the global current_stack_pointer to get the value of the stack pointer.
This change supports being able to compile the kernel with both gcc and clang.

Signed-off-by: Behan Webster <behanw@converseincode.com>
Reviewed-by: Mark Charlebois <charlebm@gmail.com>
Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-13 23:58:09 +00:00
Joe Perches 8b521cb294 ARM: 8152/1: Convert pr_warning to pr_warn
Use the more common pr_warn.

Other miscellanea:

o Coalesce formats
o Realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-26 14:39:53 +01:00
Nikolay Borisov c8bee0ad78 ARM: 8073/1: unwind: Use arm_get_current_stackframe
Make the unwind code use the correct API so that the frame pointer
is extracted from the correct register.

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 12:29:16 +01:00
Mark Charlebois e6b8075770 arm, unwind, LLVMLinux: Enable clang to be used for unwinding the stack
Patch to prevent warning of a buggy compiler when using clang and
the ARM_UNWIND option.

Clang defines (at least on the current trunk) GNUC, GNUC_MINOR, and
GNUC_PATCHLEVEL to 4, 2, and 1 respectively.

This version of GCC gets flagged as buggy, but it isn't actually an
issue with clang so the patch will do what it did before unless clang
is defined and then it will not report the GCC version as an issue.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
2014-06-07 11:44:39 -07:00
Nikolay Borisov 8203d5b628 ARM: 8052/1: unwind: Fix handling of "Pop r4-r[4+nnn],r14" opcode
The arm EABI states that unwind opcode 10100nnn means pop register r4-4[4+nnn],aditionally there is a similar unwind opcode: 10101nnn which means the same thing plus popping r14. Those two cases are handled by the unwind_exec_pop_r4_to_rN function which checks whether the 4th bit is set and does r14 popping.

However, up until now it has been checking whether the 8th bit was set (mask & 0x80) instead of the 4th (mask & 0x8), a simple to make typo but this meant that we were always popping r14 even if we had the former opcode.

This patch changes the mask so that the 2 unwind opcodes are being handled correctly.

Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Reviewed-by: Anurag Aggarwal <anurag19aggarwal@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-05-25 23:44:26 +01:00
Anurag Aggarwal a51345770e ARM: 7987/1: ARM : unwinder : Prevent data abort due to stack overflow
While unwinding backtrace, stack overflow is possible. This stack
overflow can sometimes lead to data abort in system if the area after
stack is not mapped to physical memory.

To prevent this problem from happening, execute the instructions that
can cause a data abort in separate helper functions, where a check for
feasibility is made before reading each word from the stack.

Signed-off-by: Anurag Aggarwal <a.anurag@samsung.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-02-25 11:48:24 +00:00
Uwe Kleine-König ddf5a25c5f ARM: unwinder: fix bisection to find origin in .idx section
The bisection implemented in unwind_find_origin() stopped to early.  If
there is only a single entry left to check the original code just took
the end point as origin which might be wrong.

This was introduced in commit de66a97901 ("ARM: 7187/1: fix unwinding
for XIP kernels").

Reported-and-tested-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-15 14:02:19 -08:00
Uwe Kleine-König de66a97901 ARM: 7187/1: fix unwinding for XIP kernels
The linker places the unwind tables in readonly sections. So when using
an XIP kernel these are located in ROM and cannot be modified.
For that reason the current approach to convert the relative offsets in
the unwind index to absolute addresses early in the boot process doesn't
work with XIP.

The offsets in the unwind index section are signed 31 bit numbers and
the structs are sorted by this offset. So it first has offsets between
0x40000000 and 0x7fffffff (i.e. the negative offsets) and then offsets
between 0x00000000 and 0x3fffffff. When seperating these two blocks the
numbers are sorted even when interpreting the offsets as unsigned longs.

So determine the first non-negative entry once and track that using the
new origin pointer. The actual bisection can then use a plain unsigned
long comparison. The only thing that makes the new bisection more
complicated is that the offsets are relative to their position in the
index section, so the key to search needs to be adapted accordingly in
each step.

Moreover several consts are added to catch future writes and rename the
member "addr" of struct unwind_idx to "addr_offset" to better match the
new semantic. (This has the additional benefit of breaking eventual
users at compile time to make them aware of the change.)

In my tests the new algorithm was a tad faster than the original and has
the additional upside of not needing the initial conversion and so saves
some boot time and it's possible to unwind even earlier.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-12-06 11:16:13 +00:00
Paul Gortmaker ecea4ab6d3 arm: convert core files from module.h to export.h
Many of the core ARM kernel files are not modules, but just
including module.h for exporting symbols.  Now these files can
use the lighter footprint export.h for this role.

There are probably lots more, but ARM files of mach-* and plat-*
don't get coverage via a simple yesconfig build.  They will have
to be cleaned up and tested via using their respective configs.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:49 -04:00
Will Deacon d33aadbf8e ARM: 6468/1: backtrace: fix calculation of thread stack base
When unwinding stack frames we must take care not to unwind
areas of memory that lie outside of the known extent of the stack.

This patch fixes an incorrect calculation of the stack base where
THREAD_SIZE is added to the stack pointer after it has already
been aligned to this value. Since the ALIGN macro performs this
addition internally, we end up overshooting the base by 8k.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-07 16:12:37 +00:00
Phil Carmody 5333a3de3c ARM: 6341/1: unwind - optimise linked-list searches for modules
With several sections per module, and dozens of modules, the
searches down the linked list of sections would dominate the
lookup time, dwarfing any savings from the binary search
within the section.

A simple move-to-front optimisation exploits the commonality
of the code paths taken, and in simple real-world tests reduces
the number of steps in the search to barely more than 1.

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-09-02 15:31:36 +01:00
Alexander Shishkin 830703c766 ARM: 6140/1: silence a bogus sparse warning in unwind.c
The check for compiler which is supposed to miscompile unwind tables
clearly has nothing to do with sparse (which does not define necessary
macros anyway), so simply silence it.

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-24 20:42:03 +01:00
Laurent Pinchart 51d47999b9 ARM: 5977/1: arm: Enable backtrace printing on oops when PC is corrupted
If PC points outside kernel text, start printing the backtrace at LR
instead.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-03-07 10:22:00 +00:00
Claudio Scordino 6603a4fd51 ARM: 5776/1: Check compiler version and EABI support when adding ARM unwind support.
ARM unwind is known to compile only with EABI and not-buggy compilers.
The problem is not the unwinding information but the -fno-frame-pointer
option added as a result of !CONFIG_FRAME_POINTER.  Now we check the
compiler and raise a #warning in case of wrong compiler.

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-11-02 16:59:45 +00:00
Catalin Marinas b86040a59f Thumb-2: Implementation of the unified start-up and exceptions code
This patch implements the ARM/Thumb-2 unified kernel start-up and
exception handling code.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-07-24 12:32:54 +01:00
Catalin Marinas c894ed6956 [ARM] 5558/1: Add extra checks to ARM unwinder to avoid tracing corrupt stacks
There are situations where the unwinder goes beyond stack boundaries and
unwinds random data. This patch moves the stack boundaries check after
the unwind_exec_insn() call and adds an extra check for possible
infinite loops (like "mov pc, lr" with pc == lr).

The patch also fixes a bug in the unwind instructions interpreter. The
0xb0 instruction can only set PC to LR if this wasn't already set by
a previous instruction (this is used on exceptions taken while in kernel
mode where svc_entry is annotated with ".save {r0 - pc}").

Tested-by: Tony Lindgren <tony@atomide.com>

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-06-19 16:44:22 +01:00
Catalin Marinas bff595c15c [ARM] 5383/2: unwind: Add core support for ARM stack unwinding
This patch adds the main functionality for parsing the stack unwinding
information generated by the ARM EABI toolchains. The unwinding
information consists of an index with a pair of words per function and a
table with unwinding instructions. For more information, see "Exception
Handling ABI for the ARM Architecture" at:

http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:26:24 +00:00