Commit Graph

73 Commits

Author SHA1 Message Date
Martin Schwidefsky aa33c8cbba [S390] cleanup trap handling
Move the program interruption code and the translation exception identifier
to the pt_regs structure as 'int_code' and 'int_parm_long' and make the
first level interrupt handler in entry[64].S store the two values. That
makes it possible to drop 'prot_addr' and 'trap_no' from the thread_struct
and to reduce the number of arguments to a lot of functions. Finally
un-inline do_trap. Overall this saves 5812 bytes in the .text section of
the 64 bit kernel.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-27 11:27:12 +01:00
Martin Schwidefsky c5328901aa [S390] entry[64].S improvements
Another round of cleanup for entry[64].S, in particular the program check
handler looks more reasonable now. The code size for the 31 bit kernel
has been reduced by 616 byte and by 528 byte for the 64 bit version.
Even better the code is a bit faster as well.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-27 11:27:12 +01:00
Martin Schwidefsky ddd6f9537d [S390] kvm: move cmf host id constant out of lowcore
There is no reason for the cpu-measurement-facility host id constant to
reside in the lowcore where space is precious. Use an entry in the literal
pool in HANDLE_SIE_INTERCEPT and a stack slot in sie64a.
While we are at it replace the id -1 with 0 to indicate host execution.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-27 11:27:12 +01:00
Carsten Otte 69ba974366 [S390] load user asce on sie_fault
On sie_fault we need to switch back to user ASCE. Otherwise we get
interresting effects when exiting to "userspace" while the guest
space is still active.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:44 +01:00
Martin Schwidefsky b6ef5bb3d9 [S390] add TIF_SYSCALL thread flag
Add an explicit TIF_SYSCALL bit that indicates if a task is inside
a system call. The svc_code in the pt_regs structure is now only
valid if TIF_SYSCALL is set. With this definition TIF_RESTART_SVC
can be replaced with TIF_SYSCALL. Overall do_signal is a bit more
readable and it saves a few lines of code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:43 +01:00
Martin Schwidefsky 20b40a794b [S390] signal race with restarting system calls
For a ERESTARTNOHAND/ERESTARTSYS/ERESTARTNOINTR restarting system call
do_signal will prepare the restart of the system call with a rewind of
the PSW before calling get_signal_to_deliver (where the debugger might
take control). For A ERESTART_RESTARTBLOCK restarting system call
do_signal will set -EINTR as return code.
There are two issues with this approach:
1) strace never sees ERESTARTNOHAND, ERESTARTSYS, ERESTARTNOINTR or
   ERESTART_RESTARTBLOCK as the rewinding already took place or the
   return code has been changed to -EINTR
2) if get_signal_to_deliver does not return with a signal to deliver
   the restart via the repeat of the svc instruction is left in place.
   This opens a race if another signal is made pending before the
   system call instruction can be reexecuted. The original system call
   will be restarted even if the second signal would have ended the
   system call with -EINTR.

These two issues can be solved by dropping the early rewind of the
system call before get_signal_to_deliver has been called and by using
the TIF_RESTART_SVC magic to do the restart if no signal has to be
delivered. The only situation where the system call restart via the
repeat of the svc instruction is appropriate is when a SA_RESTART
signal is delivered to user space.

Unfortunately this breaks inferior calls by the debugger again. The
system call number and the length of the system call instruction is
lost over the inferior call and user space will see ERESTARTNOHAND/
ERESTARTSYS/ERESTARTNOINTR/ERESTART_RESTARTBLOCK. To correct this a
new ptrace interface is added to save/restore the system call number
and system call instruction length.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:43 +01:00
Martin Schwidefsky 0edc8faa76 [S390] lowcore cleanup
Remove the save_area_64 field from the 0xe00 - 0xf00 area in the lowcore.
Use a free slot in the save_area array instead.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:42 +01:00
Christian Borntraeger 480e5926ce [S390] kvm: fix address mode switching
598841ca99 ([S390] use gmap address
spaces for kvm guest images) changed kvm to use a separate address
space for kvm guests. This address space was switched in __vcpu_run
In some cases (preemption, page fault) there is the possibility that
this address space switch is lost.
The typical symptom was a huge amount of validity intercepts or
random guest addressing exceptions.
Fix this by doing the switch in sie_loop and sie_exit and saving the
address space in the gmap structure itself. Also use the preempt
notifier.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2011-09-20 17:07:34 +02:00
Michael Holzheu 7dd6b3343f [S390] Add PSW restart shutdown trigger
With this patch a new S390 shutdown trigger "restart" is added. If under
z/VM "systerm restart" is entered or under the HMC the "PSW restart" button
is pressed, the PSW located at 0 (31 bit) or 0x1a0 (64 bit) bit is loaded.
Now we execute do_restart() that processes the restart action that is
defined under /sys/firmware/shutdown_actions/on_restart. Currently the
following actions are possible: reipl (default), stop, vmcmd, dump, and
dump_reipl.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2011-08-03 16:44:19 +02:00
Jan Glauber 144d634a21 [S390] fix s390 assembler code alignments
The alignment is missing for various global symbols in s390 assembly code.
With a recent gcc and an instruction like stgrl this can lead to a
specification exception if the instruction uses such a mis-aligned address.

Specify the alignment explicitely and while add it define __ALIGN for s390
and use the ENTRY define to save some lines of code.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 10:48:21 +02:00
Martin Schwidefsky 603d1a50ac [S390] move sie code to entry.S
The entry to / exit from sie has subtle dependencies to the first level
interrupt handler. Move the sie assembler code to entry64.S and replace
the SIE_HOOK callback with a test and the new _TIF_SIE bit.
In addition this patch fixes several problems in regard to the check for
the_TIF_EXIT_SIE bits. The old code checked the TIF bits before executing
the interrupt handler and it only modified the instruction address if it
pointed directly to the sie instruction. In both cases it could miss
a TIF bit that normally would cause an exit from the guest and would
reenter the guest context.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 10:48:21 +02:00
Heiko Carstens f2db2e6cb3 [S390] pfault: cpu hotplug vs missing completion interrupts
On cpu hot remove a PFAULT CANCEL command is sent to the hypervisor
which in turn will cancel all outstanding pfault requests that have
been issued on that cpu (the same happens with a SIGP cpu reset).

The result is that we end up with uninterruptible processes where
the interrupt that would wake up these processes never arrives.

In order to solve this all processes which wait for a pfault
completion interrupt get woken up after a cpu hot remove. The worst
case that could happen is that they fault again and in turn need to
wait again.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-05-23 10:24:29 +02:00
Michael Holzheu 8eb4bd666f [S390] kernel: Initialize register 14 when starting new CPU
When starting a new CPU we currently jump to start_secondary() without
setting register 14 (the return address) correctly. Therefore on the stack
frame for start_secondary an invalid return address is stored. This leads
to wrong stack back traces in kernel dumps.

Example:

 #00 [1f33fe48] cpu_idle at 10614a
 #01 [1f33fe90] start_secondary at 54fa88
 #02 [1f33feb8] (null) at 0                 <--- invalid

To fix this start_secondary() is called now with basr/brasl that sets
register 14 correctly. The output of the stack backtrace looks then
like the following:

 #00 [1f33fe48] cpu_idle at 10614a
 #01 [1f33fe90] start_secondary at 54fa88
 #02 [1f33feb8] restart_base at 54f41e      <--- correct

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-05-10 17:13:42 +02:00
Martin Schwidefsky 5e9a26928f [S390] ptrace cleanup
Overhaul program event recording and the code dealing with the ptrace
user space interface.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-05 12:47:31 +01:00
Martin Schwidefsky 860dba45e8 [S390] add kprobes annotations
Add kprobes annotations to get the massive 'probe kernel.function("*") {}'
stress test working.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-05 12:47:24 +01:00
Martin Schwidefsky 9ec2708053 [S390] fix kprobes single stepping
Fix kprobes after git commit 1e54622e04
broke it. The kprobe_handler is now called with interrupts in the state
at the time of the breakpoint. The single step of the replaced instruction
is done with interrupts off which makes it necessary to enable and disable
the interupts in the kprobes code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-29 16:50:50 +02:00
Martin Schwidefsky baa071588c [S390] cleanup system call parameter setup
Do the setup of the stack overflow argument for the sixth system
call parameter right before the branch to the system call function.
That simplifies the system call parameter access code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-25 16:10:19 +02:00
Martin Schwidefsky f6649a7e5a [S390] cleanup lowcore access from external interrupts
Read external interrupts parameters from the lowcore in the first
level interrupt handler in entry[64].S.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-25 16:10:19 +02:00
Martin Schwidefsky 1e54622e04 [S390] cleanup lowcore access from program checks
Read all required fields for program checks from the lowcore in the
first level interrupt handler in entry[64].S. If the context that
caused the fault was enabled for interrupts we can now re-enable the
irqs in entry[64].S.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-10-25 16:10:19 +02:00
Heiko Carstens f5cdac274c [S390] Fix IRQ tracing in case of PER
In case user space is single stepped (PER) the program check handler
claims too early that IRQs are enabled on the return path.
Subsequent checks will notice that the IRQ mask in the PSW and
what lockdep thinks the IRQ mask should be do not correlate and
therefore will print a warning to the console and disable lockdep.

Fix this by doing all the work within the correct context.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-07-27 19:29:42 +02:00
Heiko Carstens 2ffbb3f61e [S390] spp: remove KVM_AWARE_CMF config option
This config option enables or disables three single instructions
which aren't expensive. This is too fine grained.
Besided that everybody who uses kvm would enable it anyway in order
to debug performance problems.
Just remove it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-26 23:26:30 +02:00
Martin Schwidefsky 86f2552bbd [S390] add breaking event address for user space
Copy the last breaking event address from the lowcore to a new
field in the thread_struct on each system entry. Add a new
ptrace request PTRACE_GET_LAST_BREAK and a new utrace regset
REGSET_LAST_BREAK to query the last breaking event.

This is useful for debugging wild branches in user space code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-17 10:00:15 +02:00
Carsten Otte cd3b70f5d4 [S390] virtualization aware cpu measurement
Use the SPP instruction to set a tag on entry to / exit of the virtual
machine context. This allows the cpu measurement facility to distinguish
the samples from the host and the different guests.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
2010-05-17 10:00:15 +02:00
Martin Schwidefsky 6377981faf [S390] idle time accounting vs. machine checks
A machine check can interrupt the i/o and external interrupt handler
anytime. If the machine check occurs while the interrupt handler is
waking up from idle vtime_start_cpu can get executed a second time
and the int_clock / async_enter_timer values in the lowcore get
clobbered. This can confuse the cpu time accounting.
To fix this problem two changes are needed. First the machine check
handler has to use its own copies of int_clock and async_enter_timer,
named mcck_clock and mcck_enter_timer. Second the nested execution
of vtime_start_cpu has to be prevented. This is done in s390_idle_check
by checking the wait bit in the program status word.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-17 10:00:15 +02:00
Martin Schwidefsky 6a2df3a872 [S390] improve irq tracing code in entry[64].S
The system call path in entry[64].S is run with interrupts enabled.
Remove the irq tracing check from the system call exit code. If a
program check interrupted a context enabled for interrupts do a
call to trace_irq_off_caller in the program check handler before
branching to the system call exit code.
Restructure the system call and io interrupt return code to avoid
avoid the lpsw[e] to disable machine checks.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-17 10:00:15 +02:00
Martin Schwidefsky 43d399d2ab [S390] cleanup sysc_work and io_work code
Cleanup the #ifdef mess at io_work in entry[64].S and streamline the
TIF work code of the system call and io exit path.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-05-17 10:00:15 +02:00
Martin Schwidefsky 176b1803ce [S390] fix io_return critical section cleanup
If a machine check interrupts the io interrupt handler on one of the
instructions between io_return and io_leave the critical section
cleanup code will move the return psw to io_work_loop. By doing that
the switch from the asynchronous interrupt stack to the process stack
is skipped. If e.g. TIF_NEED_RESCHED is set things break because
the scheduler is called with the asynchronous interrupts stack.
Moving the psw back to io_return instead fixes the problem.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-04-09 13:43:02 +02:00
Heiko Carstens cbb870c822 [S390] Cleanup struct _lowcore usage and defines.
Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26 22:37:31 +01:00
Martin Schwidefsky 21ec7f6dbf [S390] fix single stepped svcs with TRACE_IRQFLAGS=y
If irq flags tracing is enabled the TRACE_IRQS_ON macros expands to
a function call which clobbers registers %r0-%r5. The macro is used
in the code path for single stepped system calls. The argument
registers %r2-%r6 need to be restored from the stack before the system
call function is called.

Cc: stable@kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-01-27 10:12:49 +01:00
Christian Borntraeger bcc6525fb2 [S390] s390: fix single stepping on svc0
On s390 there are two ways of specifying the system call number for
the svc instruction. The standard way is to use the immediate field
in the instruction (or to use EXecute for values unknown during
assemble time). This can encode 256 system calls.
The kernel ABI also allows to put the system call number in r1 and
then execute svc 0 to enable system call numbers > 255.

It turns out that single stepping svc 0 is broken, since the PER
program check handler uses r1. We have to use a different register.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-11-13 15:45:03 +01:00
Linus Torvalds 483e3cd6a3 Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (105 commits)
  ring-buffer: only enable ring_buffer_swap_cpu when needed
  ring-buffer: check for swapped buffers in start of committing
  tracing: report error in trace if we fail to swap latency buffer
  tracing: add trace_array_printk for internal tracers to use
  tracing: pass around ring buffer instead of tracer
  tracing: make tracing_reset safe for external use
  tracing: use timestamp to determine start of latency traces
  tracing: Remove mentioning of legacy latency_trace file from documentation
  tracing/filters: Defer pred allocation, fix memory leak
  tracing: remove users of tracing_reset
  tracing: disable buffers and synchronize_sched before resetting
  tracing: disable update max tracer while reading trace
  tracing: print out start and stop in latency traces
  ring-buffer: disable all cpu buffers when one finds a problem
  ring-buffer: do not count discarded events
  ring-buffer: remove ring_buffer_event_discard
  ring-buffer: fix ring_buffer_read crossing pages
  ring-buffer: remove unnecessary cpu_relax
  ring-buffer: do not swap buffers during a commit
  ring-buffer: do not reset while in a commit
  ...
2009-09-11 13:24:03 -07:00
Hendrik Brueckner a8c3cb4955 [S390] move (io|sysc)_restore_trace_psw into .data section
The sysc_restore_trace_psw and io_restore_trace_psw storage locations
are created in the .text section. When creating and IPLing from a named
saved system (NSS), writing to these locations causes a protection exception
(because the .text section is mapped as shared read-only in the NSS).

To permit write access, move the storage locations into the .data section.

The problem occurs only when CONFIG_TRACE_IRQFLAGS is set.
The git commmit that has introduced these variables is:
411788ea7f

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-11 10:29:47 +02:00
Josh Stone 6670000119 tracing: Rename FTRACE_SYSCALLS for tracepoints
s/HAVE_FTRACE_SYSCALLS/HAVE_SYSCALL_TRACEPOINTS/g
s/TIF_SYSCALL_FTRACE/TIF_SYSCALL_TRACEPOINT/g

The syscall enter/exit tracing is no longer specific to just ftrace, so
they now have names that reflect their tie to tracepoints instead.

Signed-off-by: Josh Stone <jistone@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <1251150194-1713-2-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26 00:17:35 +02:00
Heiko Carstens 9bf1226b33 [S390] ftrace: add system call tracer support
System call tracer support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 10:27:39 +02:00
Heiko Carstens bcf5cef7db [S390] secure computing arch backend
Enable secure computing on s390 as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 10:27:31 +02:00
Martin Schwidefsky 5b409ed17b [S390] cpu hotplug and accounting values
Reset the cpu timer to the maximum value and correctly initialize the
cpu accounting values in the lowcore when the cpu is started.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-04-14 15:37:27 +02:00
Martin Schwidefsky c742b31c03 [PATCH] fast vdso implementation for CLOCK_THREAD_CPUTIME_ID
The extract cpu time instruction (ectg) instruction allows the user
process to get the current thread cputime without calling into the
kernel. The code that uses the instruction needs to switch to the
access registers mode to get access to the per-cpu info page that
contains the two base values that are needed to calculate the current
cputime from the CPU timer with the ectg instruction.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:49 +01:00
Martin Schwidefsky 9cfb9b3c3a [PATCH] improve idle cputime accounting
Distinguish the cputime of the idle process where idle is actually using
cpu cycles from the cputime where idle is sleeping on an enabled wait psw.
The former is accounted as system time, the later as idle time.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-31 15:11:48 +01:00
Martin Schwidefsky c185b783b0 [S390] Remove config options.
On s390 we always want to run with precise cputime accounting.
Remove the config options VIRT_TIMER and VIRT_CPU_ACCOUNTING.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 13:39:15 +01:00
Al Viro 8f2961c39e [S390] audit: get s390 ret_from_fork in sync with other architectures
On s390 we have ret_from_fork jump not to the "do all work we
normally do on return from syscall" as on x86, ppc, etc., but to the
"do all such work except audit".  Historical reasons - the codepath
triggered when we have AUDIT process flag set is separated from the
normall one and they converge at sysc_return, which is the common
part of post-syscall work.  And does not include calling audit_syscall_exit() -
that's done in the end of sysc_tracesys path, just before that path jumps
to sysc_return.

	IOW, the child returning from fork()/clone()/vfork() doesn't
call audit_syscall_exit() at all, so no matter what we do with its
audit context, we are not going to see the audit entry.

	The fix is simple: have ret_from_fork go to the point just past
the call of sys_.... in the 'we have AUDIT flag set' path.  There we
have (64bit variant; for 31bit the situation is the same):
sysc_tracenogo:
        tm      __TI_flags+7(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
        jz      sysc_return
        la      %r2,SP_PTREGS(%r15)     # load pt_regs
        larl    %r14,sysc_return        # return point is sysc_return
        jg      do_syscall_trace_exit
which is precisely what we need - check the flag, bugger off to sysc_return
if not set, otherwise call do_syscall_trace_exit() and bugger off to
sysc_return.  r9 has just been properly set by ret_from_fork itself,
so we are fine.

	Tested on s390x, seems to work fine.  WARNING: it's been about
16 years since my last contact with 3X0 assembler[1], so additional
review would be very welcome.  I don't think I've managed to screw it
up, but...

[1] that *was* in another country and besides, the box is dead...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 13:38:07 +01:00
Martin Schwidefsky 59da21398e [S390] fix system call parameter functions.
syscall_get_nr() currently returns a valid result only if the call
chain of the traced process includes do_syscall_trace_enter(). But
collect_syscall() can be called for any sleeping task, the result of
syscall_get_nr() in general is completely bogus.

To make syscall_get_nr() work for any sleeping task the traps field
in pt_regs is replace with svcnr - the system call number the process
is executing. If svcnr == 0 the process is not on a system call path.

The syscall_get_arguments and syscall_set_arguments use regs->gprs[2]
for the first system call parameter. This is incorrect since gprs[2]
may have been overwritten with the system call number if the call
chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-11-27 11:06:56 +01:00
Heiko Carstens 50bec4ce5d [S390] ftrace: fix kernel stack backchain walking
With CONFIG_IRQSOFF_TRACER the trace_hardirqs_off() function includes
a call to __builtin_return_address(1). But we calltrace_hardirqs_off()
from early entry code. There we have just a single stack frame.
So this results in a kernel stack backchain walk that would walk beyond
the kernel stack. Following the NULL terminated backchain this results
in a lowcore read access.

To fix this we simply call trace_hardirqs_off_caller() and pass the
current instruction pointer.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-11-14 18:18:53 +01:00
Martin Schwidefsky 753c4dd6a2 [S390] ptrace changes
* System call parameter and result access functions
* Add tracehook calls
* Split syscall_trace into two functions do_syscall_trace_enter and
  do_syscall_trace_exit

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-10 21:33:57 +02:00
Christian Borntraeger 0eaeafa10f [S390] s390-kvm: leave sie context on work. Removes preemption requirement
From: Martin Schwidefsky <schwidefsky@de.ibm.com>

This patch fixes a bug with cpu bound guest on kvm-s390. Sometimes it
was impossible to deliver a signal to a spinning guest. We used
preemption as a circumvention. The preemption notifiers called
vcpu_load, which checked for pending signals and triggered a host
intercept. But even with preemption, a sigkill was not delivered
immediately.

This patch changes the low level host interrupt handler to check for the
SIE  instruction, if TIF_WORK is set. In that case we change the
instruction pointer of the return PSW to rerun the vcpu_run loop. The kvm
code sees an intercept reason 0 if that happens. This patch adds accounting
for these types of intercept as well.

The advantages:
- works with and without preemption
- signals are delivered immediately
- much better host latencies without preemption

Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-05-07 09:23:01 +02:00
Martin Schwidefsky 2688905e6a [S390] s390: Optimize user and work TIF check
On return from syscall or interrupt, we have to check if we return to
userspace (likely) and if there is work todo (less likely) to decide
if we handle the work. We can optimize this check: we first check for
the less likely work case and then check for userspace.

This patch is also a preparation for an additional patch, that fixes a bug
in KVM dealing with cpu bound guests.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-05-07 09:23:00 +02:00
Roland McGrath 02a029b325 signals: s390: renumber TIF_RESTORE_SIGMASK
TIF_RESTORE_SIGMASK no longer needs to be in the _TIF_WORK_* masks.  Those low
bits are scarce, and are all used up now.  Renumber TIF_RESTORE_SIGMASK to
free one up.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:37 -07:00
Christian Borntraeger 9e74a6b898 [S390] kernel: show last breaking-event-address on oops
Newer s390 models have a breaking-event-address-recording register.
Each time an instruction causes a break in the sequential instruction
execution, the address is saved in that hardware register. On a program
interrupt the address is copied to the lowcore address 272-279, which
makes it software accessible.

This patch changes the program check handler and the stack overflow
checker to copy the value into the pt_regs argument.
The oops output is enhanced to show the last known breaking address.
It might give additional information if the stack trace is corrupted.

The feature is only available on 64 bit.

The new oops output looks like:

[---------snip----------]
Modules linked in: vmcp sunrpc qeth_l2 dm_mod qeth ccwgroup
CPU: 2 Not tainted 2.6.24zlive-host #8
Process modprobe (pid: 4788, task: 00000000bf3d8718, ksp: 00000000b2b0b8e0)
Krnl PSW : 0704200180000000 000003e000020028 (vmcp_init+0x28/0xe4 [vmcp])
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
Krnl GPRS: 0000000004000002 000003e000020000 0000000000000000 0000000000000001
           000000000015734c ffffffffffffffff 000003e0000b3b00 0000000000000000
           000003e00007ca30 00000000b5bb5d40 00000000b5bb5800 000003e0000b3b00
           000003e0000a2000 00000000003ecf50 00000000b2b0bd50 00000000b2b0bcb0
Krnl Code: 000003e000020018: c0c000040ff4       larl    %r12,3e0000a2000
           000003e00002001e: e3e0f0000024       stg     %r14,0(%r15)
           000003e000020024: a7f40001           brc     15,3e000020026
          >000003e000020028: e310c0100004       lg      %r1,16(%r12)
           000003e00002002e: c020000413dc       larl    %r2,3e0000a27e6
           000003e000020034: c0a00004aee6       larl    %r10,3e0000b5e00
           000003e00002003a: a7490001           lghi    %r4,1
           000003e00002003e: a75900f0           lghi    %r5,240
Call Trace:
([<000000000014b300>] blocking_notifier_call_chain+0x2c/0x40)
 [<000000000015735c>] sys_init_module+0x19d8/0x1b08
 [<0000000000110afc>] sysc_noemu+0x10/0x16
 [<000002000011cda2>] 0x2000011cda2
Last Breaking-Event-Address:
 [<000003e000020024>] vmcp_init+0x24/0xe4 [vmcp]
[---------snip----------]

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:47:07 +02:00
Heiko Carstens 2bc89b5ece [S390] Fix couple of section mismatches.
Fix couple of section mismatches. And since we touch the code
anyway change the IPL code to use C99 initializers.

Cc: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-02-05 16:50:56 +01:00
Heiko Carstens b8e7a54cd0 [S390] Fix kernel preemption.
When returning from IRQ handling and TIF_NEED_RESCHED is set we must
call preempt_schedule_irq() instead of schedule().
Otherwise the BKL might be unlocked in schedule() and therfore
everything that relies on the BKL is broken.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-11-20 11:13:46 +01:00
Heiko Carstens 411788ea7f [S390] Fix irq tracing and lockdep_sys_exit calls.
Current support for TRACE_IRQFLAGS and lockdep_sys_exit is broken.
IRQ flag tracing is broken for program checks. Even worse is that
the newly introduced calls to lockdep_sys_exit are in the critical
section code which is not supposed to call any C functions. In
addition the checks if locks are still held are also done when
returning to kernel code which is broken as well.
Fix all this by disabling interrupts and machine checks at the
exit paths and then do the appropriate checks and calls.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-11-20 11:13:45 +01:00