The legacy x86 nmi watchdog code was removed with the implementation
of the perf based nmi watchdog. This broke Oprofile's nmi timer
mode. To run nmi timer mode we relied on a continuous ticking nmi
source which the nmi watchdog provided. The nmi tick was no longer
available and current watchdog can not be used anymore since it runs
with very long periods in the range of seconds. This patch
reimplements the nmi timer mode using a perf counter nmi source.

V2:
* removing pr_info()
* fix undefined reference to `__udivdi3' for 32 bit build
* fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb
* removed nmi timer setup in arch/x86
* implemented function stubs for op_nmi_init/exit()
* made code more readable in oprofile_init()

V3:
* fix architectural initialization in oprofile_init()
* fix CONFIG_OPROFILE_NMI_TIMER dependencies
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

If oprofile uses the nmi timer interrupt there is a crash while
unloading the module. The bug can be triggered with oprofile build as
module and kernel parameter nolapic set. This patch fixes this.

oprofile: using NMI timer interrupt.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58
PGD 42dbca067 PUD 41da6a067 PMD 0
Oops: 0002 [#1] PREEMPT SMP
CPU 5
Modules linked in: oprofile(-) [last unloaded: oprofile]

Pid: 2518, comm: modprobe Not tainted 3.1.0-rc7-00019-gb2fb49d #19 Advanced Micro Device Anaheim/Anaheim
RIP: 0010:[<ffffffff8123c226>]  [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58
RSP: 0018:ffff88041ef71e98  EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffffffffa0017100 RCX: dead000000200200
RDX: 0000000000000000 RSI: dead000000100100 RDI: ffffffff8178c620
RBP: ffff88041ef71ea8 R08: 0000000000000001 R09: 0000000000000082
R10: 0000000000000000 R11: ffff88041ef71de8 R12: 0000000000000080
R13: fffffffffffffff5 R14: 0000000000000001 R15: 0000000000610210
FS:  00007fc902f20700(0000) GS:ffff88042fd40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000008 CR3: 000000041cdb6000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 2518, threadinfo ffff88041ef70000, task ffff88041d348040)
Stack:
 ffff88041ef71eb8 ffffffffa0017790 ffff88041ef71eb8 ffffffffa0013532
 ffff88041ef71ec8 ffffffffa00132d6 ffff88041ef71ed8 ffffffffa00159b2
 ffff88041ef71f78 ffffffff81073115 656c69666f72706f 0000000000610200
Call Trace:
 [<ffffffffa0013532>] op_nmi_exit+0x15/0x17 [oprofile]
 [<ffffffffa00132d6>] oprofile_arch_exit+0xe/0x10 [oprofile]
 [<ffffffffa00159b2>] oprofile_exit+0x1e/0x20 [oprofile]
 [<ffffffff81073115>] sys_delete_module+0x1c3/0x22f
 [<ffffffff811bf09e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8148070b>] system_call_fastpath+0x16/0x1b
Code: 20 c6 78 81 e8 c5 cc 23 00 48 8b 13 48 8b 43 08 48 be 00 01 10 00 00 00 ad de 48 b9 00 02 20 00 00 00 ad de 48 c7 c7 20 c6 78 81
 89 42 08 48 89 10 48 89 33 48 89 4b 08 e8 a6 c0 23 00 5a 5b
RIP  [<ffffffff8123c226>] unregister_syscore_ops+0x41/0x58
 RSP <ffff88041ef71e98>
CR2: 0000000000000008
---[ end trace 43a541a52956b7b0 ]---

CC: stable@kernel.org # 2.6.37+
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Before:
   total: 5 errors, 4 warnings, 48 lines checked
After:
   total: 0 errors, 4 warnings, 49 lines checked

No code changed:

arch/x86/oprofile/init.o:

   text	   data	    bss	    dec	    hex	filename
     42	      0	      0	     42	     2a	init.o.before
     42	      0	      0	     42	     2a	init.o.after

md5:
   74c94c315cfbf245aeba36eceac57e66  init.o.before.asm
   74c94c315cfbf245aeba36eceac57e66  init.o.after.asm
Signed-off-by: NPaolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The i386 OProfile code has a function named nmi_exit(), which collides with
the nmi_exit() macro in linux/hardirq.h.  At the moment, we get away with
it, because hardirq.h isn't included in the oprofile code.  I hit this as a
bug when working with a patch which (indirectly) adds a #include of
hardirq.h to oprofile.

Regardless, the name collision is probably not a good idea, so this patch
fixes it, renaming the oprofile function to op_nmi_exit().  It also renames
the nmi_init() and nmi_timer_init() functions similarly, for consistency.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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!