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  1. 28 5月, 2013 1 次提交
  3. 22 5月, 2013 1 次提交
    • M
      m68k: implement futex.h to support userspace robust futexes and PI mutexes · e4f2dfbb
      由 Mikael Pettersson 提交于 
      Linux/M68K currently doesn't support robust futexes or PI mutexes.
The problem is that the futex code needs to perform certain ops
(cmpxchg, set, add, or, andn, xor) atomically on user-space
addresses, and M68K's lack of a futex.h causes those operations
to be unsupported and disabled.

This patch adds that support, but only for uniprocessor machines,
which is adequate for M68K.  For UP it's enough to disable preemption
to ensure mutual exclusion (futexes don't need to care about other
hardware agents), and the mandatory pagefault_disable() does just that.

This patch is closely based on the one I co-wrote for UP ARM back
in August 2008.  The main change is that this patch uses the C
get_user/put_user accessors instead of inline assembly code with
exception table fixups.

For non-MMU machines the new futex.h simply redirects to the generic
futex.h, so there is no functional change for them.

Tested on aranym with the glibc-2.17 test suite: no regressions, and
a number of mutex/condvar test cases went from failing to succeeding
(tst-mutexpi{5,5a,6,9}, tst-cond2[45], tst-robust[1-9], tst-robustpi[1-8]).
Also tested with glibc-2.18 HEAD and a local glibc patch to enable PI
mutexes: no regressions.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Acked-by: NAndreas Schwab <schwab@linux-m68k.org>
[geert: Added removal of ""generic-y += futex.h"]
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
      e4f2dfbb
  5. 01 5月, 2013 1 次提交
    • T
      dump_stack: consolidate dump_stack() implementations and unify their behaviors · 196779b9
      由 Tejun Heo 提交于 
      Both dump_stack() and show_stack() are currently implemented by each
architecture.  show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack().  On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.

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

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

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

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

This patch brings the following behavior changes.

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

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

An example WARN dump follows.

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

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

    dump_stack_print_info() is moved to kernel/printk.c from
    lib/dump_stack.c.  Because linkage is per objecct file,
    dump_stack_print_info() living in the same lib file as generic
    dump_stack() means that archs which implement custom dump_stack()
    - at this point, only blackfin - can't use dump_stack_print_info()
    as that will bring in the generic version of dump_stack() too.  v1
    The v1 patch broke build on blackfin due to this issue.  The build
    breakage was reported by Fengguang Wu.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NVineet Gupta <vgupta@synopsys.com>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NVineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>	[s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org>		[hexagon bits]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      196779b9
  7. 30 4月, 2013 1 次提交
  9. 29 4月, 2013 9 次提交
  11. 17 4月, 2013 10 次提交
  13. 16 4月, 2013 1 次提交
  15. 09 4月, 2013 1 次提交
  17. 08 4月, 2013 1 次提交
  19. 05 4月, 2013 1 次提交
  21. 21 3月, 2013 1 次提交
  23. 13 3月, 2013 1 次提交
  25. 06 3月, 2013 1 次提交
  27. 04 3月, 2013 5 次提交
  29. 28 2月, 2013 1 次提交
  31. 26 2月, 2013 1 次提交
  33. 14 2月, 2013 1 次提交
    • A
      burying unused conditionals · d64008a8
      由 Al Viro 提交于 
      __ARCH_WANT_SYS_RT_SIGACTION,
__ARCH_WANT_SYS_RT_SIGSUSPEND,
__ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND,
__ARCH_WANT_COMPAT_SYS_SCHED_RR_GET_INTERVAL - not used anymore
CONFIG_GENERIC_{SIGALTSTACK,COMPAT_RT_SIG{ACTION,QUEUEINFO,PENDING,PROCMASK}} -
can be assumed always set.
      d64008a8
  35. 09 2月, 2013 1 次提交
  37. 06 2月, 2013 1 次提交
    • G
      m68knommu: fix trap on execing /bin/init · e95c3f7a
      由 Greg Ungerer 提交于 
      As of commit fea82210 ("m68k: switch to saner kernel_execve() semantics")
the non-mmu m68k targets have trapped on booting. The execing of /bin/init
causes the exec path to try and return through a 0x0 return address - thus
trapping or otherwise hanging or crashing.

The problem isn't in the exec path as such though, but rather in the
m68knommu start_thread() macro. It is trying to clear the a6 register that
it assumes is part of a struct switch_stack below the thread registers on
our stack. But that is not what the stack frames look like when this is run.
So it ends up corrupting our call stack and zeroing out a function return
address that is sitting there.

The clearing of a6 was introduced many years ago in commit 7bf9a37d
("m68knommu: force stack alignment on ColdFire"). It used to work because
the kernel init exec code path had a short cut back to the exception return
code, and it didn't need to return through the calls on the stack.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
      e95c3f7a