current->blocked will be set to the value of current->thread_info->flags if the
cmpxchg to update thread_info->flags fails. For performance reasons the store into
current->blocked was placed in the cmpxchg loop. However, the cmpxchg overwrites the
register holding the value to be stored. In the rare case of a retry the value of
thread_info->flags will be written into current->blocked.
The fix is to use another register so that the register containing the current->blocked
value is not overwritten.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Attached is a patch against David's audit.17 kernel that adds checks
for the TIF_SYSCALL_AUDIT thread flag to the ia64 system call and
signal handling code paths. The patch enables auditing of system
calls set up via fsys_bubble_down, as well as ensuring that
audit_syscall_exit() is called on return from sigreturn.
Neglecting to check for TIF_SYSCALL_AUDIT at these points results in
incorrect information in audit_context, causing frequent system panics
when system call auditing is enabled on an ia64 system.
I have tested this patch and have seen no problems with it.
[Original patch from Amy Griffis ported to current kernel by David Woodhouse]
From: Amy Griffis <amy.griffis@hp.com>
From: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Attached is a patch against David's audit.17 kernel that adds checks
for the TIF_SYSCALL_AUDIT thread flag to the ia64 system call and
signal handling code paths.The patch enables auditing of system
calls set up via fsys_bubble_down, as well as ensuring that
audit_syscall_exit() is called on return from sigreturn.
Neglecting to check for TIF_SYSCALL_AUDIT at these points results in
incorrect information in audit_context, causing frequent system panics
when system call auditing is enabled on an ia64 system.
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This patch changes comments & formatting only. There is no code
change.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Improvements come from eliminating srlz.i, not scheduling AR/CR-reads
too early (while there are others still pending), scheduling the
backing-store switch as well as possible, splitting the BBB bundle
into a MIB/MBB pair.
Why is it safe to eliminate the srlz.i? Observe
that we used to clear bits ~PSR_PRESERVED_BITS in PSR.L. Since
PSR_PRESERVED_BITS==PSR.{UP,MFL,MFH,PK,DT,PP,SP,RT,IC}, we
ended up clearing PSR.{BE,AC,I,DFL,DFH,DI,DB,SI,TB}. However,
PSR.BE : already is turned off in __kernel_syscall_via_epc()
PSR.AC : don't care (kernel normally turns PSR.AC on)
PSR.I : already turned off by the time fsys_bubble_down gets invoked
PSR.DFL: always 0 (kernel never turns it on)
PSR.DFH: don't care --- kernel never touches f32-f127 on its own
initiative
PSR.DI : always 0 (kernel never turns it on)
PSR.SI : always 0 (kernel never turns it on)
PSR.DB : don't care --- kernel never enables kernel-level breakpoints
PSR.TB : must be 0 already; if it wasn't zero on entry to
__kernel_syscall_via_epc, the branch to fsys_bubble_down
will trigger a taken branch; the taken-trap-handler then
converts the syscall into a break-based system-call.
In other words: all the bits we're clearying are either 0 already or
are don't cares! Thus, we don't have to write PSR.L at all and we
don't have to do a srlz.i either.
Good for another ~20 cycle improvement for EPC-based heavy-weight
syscalls.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Christoph Lameter