Commit Graph

8 Commits

Author SHA1 Message Date
Cyril Bur d11994314b powerpc: signals: Stop using current in signal code
Much of the signal code takes a pt_regs on which it operates. Over
time the signal code has needed to know more about the thread than
what pt_regs can supply, this information is obtained as needed by
using 'current'.

This approach is not strictly incorrect however it does mean that
there is now a hard requirement that the pt_regs being passed around
does belong to current, this is never checked. A safer approach is for
the majority of the signal functions to take a task_struct from which
they can obtain pt_regs and any other information they need. The
caveat that the task_struct they are passed must be current doesn't go
away but can more easily be checked for.

Functions called from outside powerpc signal code are passed a pt_regs
and they can confirm that the pt_regs is that of current and pass
current to other functions, furthurmore, powerpc signal functions can
check that the task_struct they are passed is the same as current
avoiding possible corruption of current (or the task they are passed)
if this assertion ever fails.

CC: paulus@samba.org
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-10-04 16:43:07 +11:00
Michael Neuling 2b3f8e87cf powerpc/tm: Fix userspace stack corruption on signal delivery for active transactions
When in an active transaction that takes a signal, we need to be careful with
the stack.  It's possible that the stack has moved back up after the tbegin.
The obvious case here is when the tbegin is called inside a function that
returns before a tend.  In this case, the stack is part of the checkpointed
transactional memory state.  If we write over this non transactionally or in
suspend, we are in trouble because if we get a tm abort, the program counter
and stack pointer will be back at the tbegin but our in memory stack won't be
valid anymore.

To avoid this, when taking a signal in an active transaction, we need to use
the stack pointer from the checkpointed state, rather than the speculated
state.  This ensures that the signal context (written tm suspended) will be
written below the stack required for the rollback.  The transaction is aborted
becuase of the treclaim, so any memory written between the tbegin and the
signal will be rolled back anyway.

For signals taken in non-TM or suspended mode, we use the
normal/non-checkpointed stack pointer.

Tested with 64 and 32 bit signals

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-01 08:29:23 +10:00
Al Viro 574c4866e3 consolidate kernel-side struct sigaction declarations
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03 15:09:22 -05:00
Al Viro 4f4202fe5a unify default ptrace_signal_deliver
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-11-29 00:01:23 -05:00
David Howells c3617f7203 UAPI: (Scripted) Disintegrate arch/powerpc/include/asm
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
2012-10-09 09:47:26 +01:00
Arnd Bergmann 63b852a6b6 asm-generic: rename termios.h, signal.h and mman.h
The existing asm-generic versions are incomplete and included
by some architectures. New architectures should be able
to use a generic version, so rename the existing files and
change all users, which lets us add the new files.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2009-06-11 21:01:52 +02:00
Al Viro 2e074004c6 x86, um: get rid of uml signal.h
the only theoretical reason for it these days is ppc; aside of uml/ppc
being dead, do_signal() would be happier in arch/powerpc/kernel/signal.h
anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:20 -07:00
Stephen Rothwell b8b572e101 powerpc: Move include files to arch/powerpc/include/asm
from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-04 12:02:00 +10:00