Commit Graph

110 Commits

Author SHA1 Message Date
Mike Travis fc8b13740b kgdb/kdb: Fix no KDB config problem
Some code added to the debug_core module had KDB dependencies
that it shouldn't have.  Move the KDB dependent REASON back to
the caller to remove the dependency in the debug core code.

Update the call from the UV NMI handler to conform to the new
interface.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20140114162551.318251993@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-25 08:55:09 +01:00
Mike Travis 8daaa5f826 kdb: Add support for external NMI handler to call KGDB/KDB
This patch adds a kgdb_nmicallin() interface that can be used by
external NMI handlers to call the KGDB/KDB handler.  The primary
need for this is for those types of NMI interrupts where all the
CPUs have already received the NMI signal.  Therefore no
send_IPI(NMI) is required, and in fact it will cause a 2nd
unhandled NMI to occur. This generates the "Dazed and Confuzed"
messages.

Since all the CPUs are getting the NMI at roughly the same time,
it's not guaranteed that the first CPU that hits the NMI handler
will manage to enter KGDB and set the dbg_master_lock before the
slaves start entering. The new argument "send_ready" was added
for KGDB to signal the NMI handler to release the slave CPUs for
entry into KGDB.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20131002151417.928886849@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-03 18:47:54 +02:00
zhangwei(Jovi) f345650964 kgdb/sysrq: fix inconstistent help message of sysrq key
Currently help message of /proc/sysrq-trigger highlight its upper-case
characters, like below:

      SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
      memory-full-oom-kill(F) kill-all-tasks(I) ...

this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.

This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.

This patch fix kgdb sysrq key: "debug(g)"

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 17:04:10 -07:00
Linus Torvalds 3cfb07743a KGDB/KDB fixes and cleanups
Cleanups
    Remove kdb ssb command - there is no in kernel disassembler to support it
    Remove kdb ll command - Always caused a kernel oops and there were no
        bug reports so no one was using this command
    Use kernel ARRAY_SIZE macro instead of array computations
 
  Fixes
    Stop oops in kdb if user executes kdb_defcmd with args
    kdb help command truncated text
    ppc64 support for kgdbts
    Add missing kconfig option from original kdb port for dealing with
       catastrophic kernel crashes such that you can reboot automatically
       on continue from kdb
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Merge tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "For a change we removed more code than we added.  If people aren't
  using it we shouldn't be carrying it.  :-)

  Cleanups:
   - Remove kdb ssb command - there is no in kernel disassembler to
     support it

   - Remove kdb ll command - Always caused a kernel oops and there were
     no bug reports so no one was using this command

   - Use kernel ARRAY_SIZE macro instead of array computations

  Fixes:
   - Stop oops in kdb if user executes kdb_defcmd with args

   - kdb help command truncated text

   - ppc64 support for kgdbts

   - Add missing kconfig option from original kdb port for dealing with
     catastrophic kernel crashes such that you can reboot automatically
     on continue from kdb"

* tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kdb: Remove unhandled ssb command
  kdb: Prevent kernel oops with kdb_defcmd
  kdb: Remove the ll command
  kdb_main: fix help print
  kdb: Fix overlap in buffers with strcpy
  Fixed dead ifdef block by adding missing Kconfig option.
  kdb: Setup basic kdb state before invoking commands via kgdb
  kdb: use ARRAY_SIZE where possible
  kgdb/kgdbts: support ppc64
  kdb: A fix for kdb command table expansion
2013-03-02 08:31:39 -08:00
Vincent 36dfea42cc kdb: Remove unhandled ssb command
The 'ssb' command can only be handled when we have a disassembler, to check for
branches, so remove the 'ssb' command for now.

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:20 -06:00
Jason Wessel a37372f6c3 kdb: Prevent kernel oops with kdb_defcmd
The kdb_defcmd can only be used to display the available command aliases
while using the kernel debug shell.  If you try to define a new macro
while the kernel debugger is active it will oops.  The debug shell
macros must use pre-allocated memory set aside at the time kdb_init()
is run, and the kdb_defcmd is restricted to only working at the time
that the kdb_init sequence is being run, which only occurs if you
actually activate the kernel debugger.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:19 -06:00
Jason Wessel 1b2caa2dcb kdb: Remove the ll command
Recently some code inspection was done after fixing a problem with
kmalloc used while in the kernel debugger context (which is not
legal), and it turned up the fact that kdb ll command will oops the
kernel.

Given that there have been zero bug reports on the command combined
with the fact it will oops the kernel it is clearly not being used.
Instead of fixing it, it will be removed.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:19 -06:00
Jason Wessel 074604af21 kdb_main: fix help print
The help command was chopping all the usage instructions such that
they were not readable.

Example:

bta             [D|R|S|T|C|Z|E|U|I| Backtrace all processes matching state flag
per_cpu         <sym> [<bytes>] [<c Display per_cpu variables

Where as it should look like:

bta             [D|R|S|T|C|Z|E|U|I|M|A]
                                    Backtrace all processes matching state flag
per_cpu         <sym> [<bytes>] [<cpu>]
                                    Display per_cpu variables

All that is needed is to check the how long the cmd_usage is and jump
to the next line when appropriate.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:18 -06:00
Jason Wessel 4eb7a66d94 kdb: Fix overlap in buffers with strcpy
Maxime reported that strcpy(s->usage, s->usage+1) has no definitive
guarantee that it will work on all archs the same way when you have
overlapping memory.  The fix is simple for the kdb code because we
still have the original string memory in the function scope, so we
just have to use that as the argument instead.

Reported-by: Maxime Villard <rustyBSD@gmx.fr>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:18 -06:00
Matt Klein 00370b8f8d kdb: Setup basic kdb state before invoking commands via kgdb
Although invasive kdb commands are not supported via kgdb, some useful
non-invasive commands like bt* require basic kdb state to be setup before
calling into the kdb code. Factor out some of this code and call it before
and after executing kdb commands via kgdb.

Signed-off-by: Matt Klein <mklein@twitter.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:17 -06:00
Sasha Levin 5f784f798c kdb: use ARRAY_SIZE where possible
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:17 -06:00
John Blackwood f7c82d5a3c kdb: A fix for kdb command table expansion
When locally adding in some additional kdb commands, I stumbled
across an issue with the dynamic expansion of the kdb command table.
When the number of kdb commands exceeds the size of the statically
allocated kdb_base_commands[] array, additional space is allocated in
the kdb_register_repeat() routine.

The unused portion of the newly allocated array was not being initialized
to zero properly and this would result in segfaults when help '?' was
executed or when a search for a non-existing command would traverse the
command table beyond the end of valid command entries and then attempt
to use the non-zeroed area as actual command entries.

Signed-off-by: John Blackwood <john.blackwood@ccur.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:16 -06:00
Greg Kroah-Hartman 16559ae48c kgdb: remove #include <linux/serial_8250.h> from kgdb.h
There's no reason kgdb.h itself needs to include the 8250 serial port
header file.  So push it down to the _very_ limited number of individual
drivers that need the values in that file, and fix up the places where
people really wanted serial_core.h and platform_device.h.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-04 15:35:26 -08:00
Rusty Russell 0d21b0e347 module: add new state MODULE_STATE_UNFORMED.
You should never look at such a module, so it's excised from all paths
which traverse the modules list.

We add the state at the end, to avoid gratuitous ABI break (ksplice).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-01-12 13:27:05 +10:30
Linus Torvalds 6c536a17fa KGDB/KDB fixes and cleanups
Cleanups
    Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
    Add module event hooks for simplified debugging with gdb
  Fixes
    Fix kdb to stop paging with 'q' on bta and dmesg
    Fix for data that scrolls off the vga console due to line wrapping
      when using the kdb pager
  New
    The debug core registers for kernel module events which allows a
      kernel aware gdb to automatically load symbols and break on entry
      to a kernel module
    Allow kgdboc=kdb to setup kdb on the vga console
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Merge tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "Cleanups
   - Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
   - Add module event hooks for simplified debugging with gdb
 Fixes
   - Fix kdb to stop paging with 'q' on bta and dmesg
   - Fix for data that scrolls off the vga console due to line wrapping
     when using the kdb pager
 New
   - The debug core registers for kernel module events which allows a
     kernel aware gdb to automatically load symbols and break on entry
     to a kernel module
   - Allow kgdboc=kdb to setup kdb on the vga console"

* tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  tty/console: fix warnings in drivers/tty/serial/kgdboc.c
  kdb,vt_console: Fix missed data due to pager overruns
  kdb: Fix dmesg/bta scroll to quit with 'q'
  kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shell
  kgdb,x86: fix warning about unused variable
  mips,kgdb: fix recursive page fault with CONFIG_KPROBES
  kgdb: Add module event hooks
2012-10-13 11:16:58 +09:00
Jason Wessel 17b572e820 kdb,vt_console: Fix missed data due to pager overruns
It is possible to miss data when using the kdb pager.  The kdb pager
does not pay attention to the maximum column constraint of the screen
or serial terminal.  This result is not incrementing the shown lines
correctly and the pager will print more lines that fit on the screen.
Obviously that is less than useful when using a VGA console where you
cannot scroll back.

The pager will now look at the kdb_buffer string to see how many
characters are printed.  It might not be perfect considering you can
output ASCII that might move the cursor position, but it is a
substantially better approximation for viewing dmesg and trace logs.

This also means that the vt screen needs to set the kdb COLUMNS
variable.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-10-12 06:37:35 -05:00
Jason Wessel d1871b38fc kdb: Fix dmesg/bta scroll to quit with 'q'
If you press 'q' the pager should exit instead of printing everything
from dmesg which can really bog down a 9600 baud serial link.

The same is true for the bta command.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-10-12 06:37:35 -05:00
Jason Wessel f30fed10c4 kgdb: Add module event hooks
Allow gdb to auto load kernel modules when it is attached,
which makes it trivially easy to debug module init functions
or pre-set breakpoints in a kernel module that has not loaded yet.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-10-12 06:37:33 -05:00
Anton Vorontsov ad394f66fa kdb: Implement disable_nmi command
This command disables NMI-entry. If NMI source has been previously shared
with a serial console ("debug port"), this effectively releases the port
from KDB exclusive use, and makes the console available for normal use.

Of course, NMI can be reenabled, enable_nmi modparam is used for that:

	echo 1 > /sys/module/kdb/parameters/enable_nmi

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-26 13:42:25 -07:00
Anton Vorontsov 5a14fead07 kernel/debug: Mask KGDB NMI upon entry
The new arch callback should manage NMIs that usually cause KGDB to
enter. That is, not all NMIs should be enabled/disabled, but only
those that issue kgdb_handle_exception().

We must mask it as serial-line interrupt can be used as an NMI, so
if the original KGDB-entry cause was say a breakpoint, then every
input to KDB console will cause KGDB to reenter, which we don't want.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-26 13:42:25 -07:00
Anton Vorontsov b10d22d6e8 kernel/debug: Make use of KGDB_REASON_NMI
Currently kernel never set KGDB_REASON_NMI. We do now, when we enter
KGDB/KDB from an NMI.

This is not to be confused with kgdb_nmicallback(), NMI callback is
an entry for the slave CPUs during CPUs roundup, but REASON_NMI is the
entry for the master CPU.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-07-31 08:16:43 -05:00
Jason Wessel 07cd27bbd4 kdb: Remove cpu from the more prompt
Having the CPU in the more prompt is completely redundent vs the
standard kdb prompt, and it also wastes 32 bytes on the stack.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-07-31 08:16:43 -05:00
Jason Wessel 0f26d0e0a7 kdb: Remove unused KDB_FLAG_ONLY_DO_DUMP
This code cleanup was missed in the original kdb merge, and this code
is simply not used at all.  The code that was previously used to set
the KDB_FLAG_ONLY_DO_DUMP was removed prior to the initial kdb merge.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-07-31 08:16:42 -05:00
Anton Vorontsov c064da4714 kdb: Switch to nolock variants of kmsg_dump functions
The locked variants are prone to deadlocks (suppose we got to the
debugger w/ the logbuf lock held), so let's switch to nolock variants.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-21 10:34:00 -07:00
Anton Vorontsov 1b499d05ee printk: Remove kdb_syslog_data
The function is no longer needed, so remove it.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-21 10:34:00 -07:00
Anton Vorontsov bc792e612e kdb: Revive dmesg command
The kgdb dmesg command is broken after the printk rework.  The old logic
in kdb code makes no sense in terms of current printk/logging storage
format, and KDB simply hangs forever.

This patch revives the command by switching to kmsg_dumper iterator.

The code is now much more simpler and shorter.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-21 10:34:00 -07:00
Linus Torvalds 6c216ec636 KGDB/KDB regression fixes
3.4: Fix an an Smatch warning that appeared in the 3.4 merge window
    3.0: Fix kgdb test suite with SMP for all archs without HW single stepping
 2.6.36: Fix kgdb sw breakpoints with CONFIG_DEBUG_RODATA=y limitations on x86
 2.6.26: Fix oops on kgdb test suite with CONFIG_DEBUG_RODATA
         Fix kgdb test suite with SMP for all archs with HW single stepping
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Merge tag 'for_linus-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB regression fixes from Jason Wessel:
 - Fix a Smatch warning that appeared in the 3.4 merge window
 - Fix kgdb test suite with SMP for all archs without HW single stepping
 - Fix kgdb sw breakpoints with CONFIG_DEBUG_RODATA=y limitations on x86
 - Fix oops on kgdb test suite with CONFIG_DEBUG_RODATA
 - Fix kgdb test suite with SMP for all archs with HW single stepping

* tag 'for_linus-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  x86,kgdb: Fix DEBUG_RODATA limitation using text_poke()
  kgdb,debug_core: pass the breakpoint struct instead of address and memory
  kgdbts: (2 of 2) fix single step awareness to work correctly with SMP
  kgdbts: (1 of 2) fix single step awareness to work correctly with SMP
  kgdbts: Fix kernel oops with CONFIG_DEBUG_RODATA
  kdb: Fix smatch warning on dbg_io_ops->is_console
2012-04-04 17:26:08 -07:00
Jason Wessel 98b54aa1a2 kgdb,debug_core: pass the breakpoint struct instead of address and memory
There is extra state information that needs to be exposed in the
kgdb_bpt structure for tracking how a breakpoint was installed.  The
debug_core only uses the the probe_kernel_write() to install
breakpoints, but this is not enough for all the archs.  Some arch such
as x86 need to use text_poke() in order to install a breakpoint into a
read only page.

Passing the kgdb_bpt structure to kgdb_arch_set_breakpoint() and
kgdb_arch_remove_breakpoint() allows other archs to set the type
variable which indicates how the breakpoint was installed.

Cc: stable@vger.kernel.org # >= 2.6.36
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-29 17:41:25 -05:00
Jason Wessel 78724b8ef8 kdb: Fix smatch warning on dbg_io_ops->is_console
The Smatch tool warned that the change from commit b8adde8dd
(kdb: Avoid using dbg_io_ops until it is initialized) should
add another null check later in the kdb_printf().

It is worth noting that the second use of dbg_io_ops->is_console
is protected by the KDB_PAGER state variable which would only
get set when kdb is fully active and initialized.  If we
ever encounter changes or defects in the KDB_PAGER state
we do not want to crash the kernel in a kdb_printf/printk.

CC: Tim Bird <tim.bird@am.sony.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-29 17:41:23 -05:00
Linus Torvalds 0195c00244 Disintegrate and delete asm/system.h
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Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system

Pull "Disintegrate and delete asm/system.h" from David Howells:
 "Here are a bunch of patches to disintegrate asm/system.h into a set of
  separate bits to relieve the problem of circular inclusion
  dependencies.

  I've built all the working defconfigs from all the arches that I can
  and made sure that they don't break.

  The reason for these patches is that I recently encountered a circular
  dependency problem that came about when I produced some patches to
  optimise get_order() by rewriting it to use ilog2().

  This uses bitops - and on the SH arch asm/bitops.h drags in
  asm-generic/get_order.h by a circuituous route involving asm/system.h.

  The main difficulty seems to be asm/system.h.  It holds a number of
  low level bits with no/few dependencies that are commonly used (eg.
  memory barriers) and a number of bits with more dependencies that
  aren't used in many places (eg.  switch_to()).

  These patches break asm/system.h up into the following core pieces:

    (1) asm/barrier.h

        Move memory barriers here.  This already done for MIPS and Alpha.

    (2) asm/switch_to.h

        Move switch_to() and related stuff here.

    (3) asm/exec.h

        Move arch_align_stack() here.  Other process execution related bits
        could perhaps go here from asm/processor.h.

    (4) asm/cmpxchg.h

        Move xchg() and cmpxchg() here as they're full word atomic ops and
        frequently used by atomic_xchg() and atomic_cmpxchg().

    (5) asm/bug.h

        Move die() and related bits.

    (6) asm/auxvec.h

        Move AT_VECTOR_SIZE_ARCH here.

  Other arch headers are created as needed on a per-arch basis."

Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that.  We'll find out anything that got broken and fix it..

* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
  Delete all instances of asm/system.h
  Remove all #inclusions of asm/system.h
  Add #includes needed to permit the removal of asm/system.h
  Move all declarations of free_initmem() to linux/mm.h
  Disintegrate asm/system.h for OpenRISC
  Split arch_align_stack() out from asm-generic/system.h
  Split the switch_to() wrapper out of asm-generic/system.h
  Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
  Create asm-generic/barrier.h
  Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
  Disintegrate asm/system.h for Xtensa
  Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
  Disintegrate asm/system.h for Tile
  Disintegrate asm/system.h for Sparc
  Disintegrate asm/system.h for SH
  Disintegrate asm/system.h for Score
  Disintegrate asm/system.h for S390
  Disintegrate asm/system.h for PowerPC
  Disintegrate asm/system.h for PA-RISC
  Disintegrate asm/system.h for MN10300
  ...
2012-03-28 15:58:21 -07:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Linus Torvalds a20ae85aba Fixes:
- Fix KDB keyboard repeat scan codes and leaked keyboard events
 - Fix kernel crash with kdb_printf() for users who compile new kdb_printf()'s
   in early code
 - Return all segment registers to gdb on x86_64
 Features:
 - KDB/KGDB hook the reboot notifier and end user can control if it stops,
   detaches or does nothing (updated docs as well)
 - Notify users who use CONFIG_DEBUG_RODATA to use hw breakpoints
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Merge tag 'for_linus-3.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB updates from Jason Wessel:
 "Fixes:
   - Fix KDB keyboard repeat scan codes and leaked keyboard events
   - Fix kernel crash with kdb_printf() for users who compile new
     kdb_printf()'s in early code
   - Return all segment registers to gdb on x86_64

  Features:
   - KDB/KGDB hook the reboot notifier and end user can control if it
     stops, detaches or does nothing (updated docs as well)
   - Notify users who use CONFIG_DEBUG_RODATA to use hw breakpoints"

* tag 'for_linus-3.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kdb: Add message about CONFIG_DEBUG_RODATA on failure to install breakpoint
  kdb: Avoid using dbg_io_ops until it is initialized
  kgdb,debug_core: add the ability to control the reboot notifier
  KDB: Fix usability issues relating to the 'enter' key.
  kgdb,debug-core,gdbstub: Hook the reboot notifier for debugger detach
  kgdb: Respect that flush op is optional
  kgdb: x86: Return all segment registers also in 64-bit mode
2012-03-23 09:29:44 -07:00
Jason Wessel 1ba0c1720e kdb: Add message about CONFIG_DEBUG_RODATA on failure to install breakpoint
On x86, if CONFIG_DEBUG_RODATA is set, one cannot set breakpoints
via KDB.  Apparently this is a well-known problem, as at least one distribution
now ships with both KDB enabled and CONFIG_DEBUG_RODATA=y for security reasons.

This patch adds an printk message to the breakpoint failure case,
in order to provide suggestions about how to use the debugger.

Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Tim Bird <tim.bird@am.sony.com>
2012-03-22 15:07:16 -05:00
Tim Bird b8adde8dde kdb: Avoid using dbg_io_ops until it is initialized
This fixes a bug with setting a breakpoint during kdb initialization
(from kdb_cmds).  Any call to kdb_printf() before the initialization
of the kgdboc serial console driver (which happens much later during
bootup than kdb_init), results in kernel panic due to the use of
dbg_io_ops before it is initialized.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-22 15:07:16 -05:00
Jason Wessel bec4d62ead kgdb,debug_core: add the ability to control the reboot notifier
Sometimes it is desirable to stop the kernel debugger before allowing
a system to reboot either with kdb or kgdb.  This patch adds the
ability to turn the reboot notifier on and off or enter the debugger
and stop kernel execution before rebooting.

It is possible to change the setting after booting the kernel with the
following:

echo 1 > /sys/module/debug_core/parameters/kgdbreboot

It is also possible to change this setting using kdb / kgdb to
manipulate the variable directly.

Using KDB:
   mm kgdbreboot 1

Using gdb:
   set kgdbreboot=1

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-22 15:07:16 -05:00
Andrei Warkentin 8f30d41176 KDB: Fix usability issues relating to the 'enter' key.
This fixes the following problems:
1) Typematic-repeat of 'enter' gives warning message
   and leaks make/break if KDB exits. Repeats
   look something like 0x1c 0x1c .... 0x9c
2) Use of 'keypad enter' gives warning message and
   leaks the ENTER break/make code out if KDB exits.
   KP ENTER repeats look someting like 0xe0 0x1c
   0xe0 0x1c ... 0xe0 0x9c.
3) Lag on the order of seconds between "break" and "make" when
   expecting the enter "break" code. Seen under virtualized
   environments such as VMware ESX.

The existing special enter handler tries to glob the enter break code,
but this fails if the other (KP) enter was used, or if there was a key
repeat. It also fails if you mashed some keys along with enter, and
you ended up with a non-enter make or non-enter break code coming
after the enter make code. So first, we modify the handler to handle
these cases. But performing these actions on every enter is annoying
since now you can't hold ENTER down to scroll <more>d messages in
KDB. Since this special behaviour is only necessary to handle the
exiting KDB ('g' + ENTER) without leaking scancodes to the OS.  This
cleanup needs to get executed anytime the kdb_main loop exits.

Tested on QEMU. Set a bp on atkbd.c to verify no scan code was leaked.

Cc: Andrei Warkentin <andreiw@vmware.com>
[jason.wessel@windriver.com: move cleanup calls to kdb_main.c]
Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-22 15:07:15 -05:00
Jason Wessel 2366e04784 kgdb,debug-core,gdbstub: Hook the reboot notifier for debugger detach
The gdbstub and kdb should get detached if the system is rebooting.
Calling gdbstub_exit() will set the proper debug core state and send a
message to any debugger that is connected to correctly detach.

An attached debugger will receive the exit code from
include/linux/reboot.h based on SYS_HALT, SYS_REBOOT, etc...

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-22 15:07:15 -05:00
Jan Kiszka 9fbe465efc kgdb: Respect that flush op is optional
Not all kgdb I/O drivers implement a flush operation. Adjust
gdbstub_exit accordingly.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-03-22 15:07:15 -05:00
Cong Wang d762a50b5b kdb: remove the second argument of k[un]map_atomic()
Signed-off-by: Cong Wang <amwang@redhat.com>
2012-03-20 21:48:26 +08:00
Eric Dumazet bd77c04772 module: struct module_ref should contains long fields
module_ref contains two "unsigned int" fields.

Thats now too small, since some machines can open more than 2^32 files.

Check commit 518de9b39e (fs: allow for more than 2^31 files) for
reference.

We can add an aligned(2 * sizeof(unsigned long)) attribute to force
alloc_percpu() allocating module_ref areas in single cache lines.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Tejun Heo <tj@kernel.org>
CC: Robin Holt <holt@sgi.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-13 09:32:14 +10:30
Paul E. McKenney 7fc20c5cbd kdb: Make KDB use the new is_idle_task() API
Change from direct comparison of ->pid with zero to is_idle_task().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11 10:31:52 -08:00
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Andy Shevchenko 50e1499f46 kgdb: follow rename pack_hex_byte() to hex_byte_pack()
There is no functional change.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:56 -07:00
Paul Gortmaker 6e5fdeedca kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure
These files were getting <linux/module.h> via an implicit non-obvious
path, but we want to crush those out of existence since they cost
time during compiles of processing thousands of lines of headers
for no reason.  Give them the lightweight header that just contains
the EXPORT_SYMBOL infrastructure.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:05 -04:00
Linus Torvalds 72f9adfd20 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kdb,kgdb: Allow arbitrary kgdb magic knock sequences
  kdb: Remove all references to DOING_KGDB2
  kdb,kgdb: Implement switch and pass buffer from kdb -> gdb
  kdb: cleanup unused variables missed in the original kdb merge
2011-08-01 13:39:40 -10:00
Jason Wessel 37f86b469d kdb,kgdb: Allow arbitrary kgdb magic knock sequences
The first packet that gdb sends when the kernel is in kdb mode seems
to change with every release of gdb.  Instead of continuing to add
many different gdb packets, change kdb to automatically look for any
thing that looks like a gdb packet.

Example 1 cold start test:
echo g > /proc/sysrq-trigger
$D#44+

Example 2 cold start test:
echo g > /proc/sysrq-trigger
$3#33

The second one should re-enter kdb's shell right away and is purely a
test.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2011-08-01 13:23:59 -05:00
Jason Wessel d613d828e8 kdb: Remove all references to DOING_KGDB2
The DOING_KGDB2 was originally a state variable for one of the two
ways to automatically transition from kdb to kgdb.  Purge all these
variables and just use one single state for the transition.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2011-08-01 13:23:59 -05:00
Jason Wessel f679c4985b kdb,kgdb: Implement switch and pass buffer from kdb -> gdb
When switching from kdb mode to kgdb mode packets were getting lost
depending on the size of the fifo queue of the serial chip.  When gdb
initially connects if it is in kdb mode it should entirely send any
character buffer over to the gdbstub when switching connections.

Previously kdb was zero'ing out the character buffer and this could
lead to gdb failing to connect at all, or a lengthy pause could occur
on the initial connect.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2011-08-01 13:23:59 -05:00
Jason Wessel 3bdb65ec95 kdb: cleanup unused variables missed in the original kdb merge
The BTARGS and BTSYMARG variables do not have any function in the
mainline version of kdb.

Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2011-08-01 13:23:58 -05:00
Arun Sharma 60063497a9 atomic: use <linux/atomic.h>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:47 -07:00