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  1. 15 Aug, 2009 1 commit
    • Mikael Pettersson's avatar
      ARM: 5677/1: ARM support for TIF_RESTORE_SIGMASK/pselect6/ppoll/epoll_pwait · 36984265
      Mikael Pettersson authored 
      This patch adds support for TIF_RESTORE_SIGMASK to ARM's
signal handling, which allows to hook up the pselect6, ppoll,
and epoll_pwait syscalls on ARM.

Tested here with eabi userspace and a test program with a
deliberate race between a child's exit and the parent's
sigprocmask/select sequence. Using sys_pselect6() instead
of sigprocmask/select reliably prevents the race.

The other arch's support for TIF_RESTORE_SIGMASK has evolved
over time:

In 2.6.16:
- add TIF_RESTORE_SIGMASK which parallels TIF_SIGPENDING
- test both when checking for pending signal [changed later]
- reimplement sys_sigsuspend() to use current->saved_sigmask,
  TIF_RESTORE_SIGMASK [changed later], and -ERESTARTNOHAND;
  ditto for sys_rt_sigsuspend(), but drop private code and
  use common code via __ARCH_WANT_SYS_RT_SIGSUSPEND;
- there are now no "extra" calls to do_signal() so its oldset
  parameter is always &current->blocked so need not be passed,
  also its return value is changed to void
- change handle_signal() to return 0/-errno
- change do_signal() to honor TIF_RESTORE_SIGMASK:
  + get oldset from current->saved_sigmask if TIF_RESTORE_SIGMASK
    is set
  + if handle_signal() was successful then clear TIF_RESTORE_SIGMASK
  + if no signal was delivered and TIF_RESTORE_SIGMASK is set then
    clear it and restore the sigmask
- hook up sys_pselect6() and sys_ppoll()

In 2.6.19:
- hook up sys_epoll_pwait()

In 2.6.26:
- allow archs to override how TIF_RESTORE_SIGMASK is implemented;
  default set_restore_sigmask() sets both TIF_RESTORE_SIGMASK and
  TIF_SIGPENDING; archs need now just test TIF_SIGPENDING again
  when checking for pending signal work; some archs now implement
  TIF_RESTORE_SIGMASK as a secondary/non-atomic thread flag bit
- call set_restore_sigmask() in sys_sigsuspend() instead of setting
  TIF_RESTORE_SIGMASK

In 2.6.29-rc:
- kill sys_pselect7() which no arch wanted

So for 2.6.31-rc6/ARM this patch does the following:
- Add TIF_RESTORE_SIGMASK. Use the generic set_restore_sigmask()
  which sets both TIF_SIGPENDING and TIF_RESTORE_SIGMASK, so
  TIF_RESTORE_SIGMASK need not claim one of the scarce low thread
  flags, and existing TIF_SIGPENDING and _TIF_WORK_MASK tests need
  not be extended for TIF_RESTORE_SIGMASK.
- sys_sigsuspend() is reimplemented to use current->saved_sigmask
  and set_restore_sigmask(), making it identical to most other archs
- The private code for sys_rt_sigsuspend() is removed, instead
  generic code supplies it via __ARCH_WANT_SYS_RT_SIGSUSPEND.
- sys_sigsuspend() and sys_rt_sigsuspend() no longer need a pt_regs
  parameter, so their assembly code wrappers are removed.
- handle_signal() is changed to return 0 on success or -errno.
- The oldset parameter to do_signal() is now redundant and removed,
  and the return value is now also redundant and changed to void.
- do_signal() is changed to honor TIF_RESTORE_SIGMASK:
  + get oldset from current->saved_sigmask if TIF_RESTORE_SIGMASK
    is set
  + if handle_signal() was successful then clear TIF_RESTORE_SIGMASK
  + if no signal was delivered and TIF_RESTORE_SIGMASK is set then
    clear it and restore the sigmask
- Hook up sys_pselect6, sys_ppoll, and sys_epoll_pwait.
Signed-off-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      36984265
  3. 21 Jul, 2009 1 commit
    • Uwe Kleine-König's avatar
      [ARM] 5613/1: implement CALLER_ADDRESSx · 4bf1fa5a
      Uwe Kleine-König authored 
      From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

As __builtin_return_address(n) doesn't work for ARM with n > 0, the
kernel needs its own implementation.

This fixes many warnings saying:

	warning: unsupported argument to '__builtin_return_address'

The new methods and walk_stackframe must not be instrumented because
CALLER_ADDRESSx is used in the various tracers and tracing the tracer is
a bad idea.

What's currently missing is an implementation using unwind tables.  This
is not fatal though, it's just that the tracers don't get enough
information to be really useful.

Note that if both ARM_UNWIND and FRAME_POINTER are enabled,
walk_stackframe uses unwind information.  So in this case the same
implementation is used as when FRAME_POINTER is disabled.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      4bf1fa5a
  5. 11 Jul, 2009 17 commits
  7. 10 Jul, 2009 21 commits
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