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Andy Lutomirski 8b4777a4b5 x86-64: Document some of entry_64.S
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/fc134867cc550977cc996866129e11a16ba0f9ea.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-05 21:30:32 +02:00
Lucas De Marchi 0d2eb44f63 x86: Fix common misspellings
They were generated by 'codespell' and then manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: trivial@kernel.org
LKML-Reference: <1300389856-1099-3-git-send-email-lucas.demarchi@profusion.mobi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-18 10:39:30 +01:00
Linus Torvalds 181f977d13 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (93 commits)
  x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()
  x86-64, NUMA: Don't call numa_set_distanc() for all possible node combinations during emulation
  x86-64, NUMA: Don't assume phys node 0 is always online in numa_emulation()
  x86-64, NUMA: Clean up initmem_init()
  x86-64, NUMA: Fix numa_emulation code with node0 without RAM
  x86-64, NUMA: Revert NUMA affine page table allocation
  x86: Work around old gas bug
  x86-64, NUMA: Better explain numa_distance handling
  x86-64, NUMA: Fix distance table handling
  mm: Move early_node_map[] reverse scan helpers under HAVE_MEMBLOCK
  x86-64, NUMA: Fix size of numa_distance array
  x86: Rename e820_table_* to pgt_buf_*
  bootmem: Move __alloc_memory_core_early() to nobootmem.c
  bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c
  bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c
  x86-64, NUMA: Seperate out numa_alloc_distance() from numa_set_distance()
  x86-64, NUMA: Add proper function comments to global functions
  x86-64, NUMA: Move NUMA emulation into numa_emulation.c
  x86-64, NUMA: Prepare numa_emulation() for moving NUMA emulation into a separate file
  x86-64, NUMA: Do not scan two times for setup_node_bootmem()
  ...

Fix up conflicts in arch/x86/kernel/smpboot.c
2011-03-15 19:49:10 -07:00
Linus Torvalds da849abeb8 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, binutils, xen: Fix another wrong size directive
  x86: Remove dead config option X86_CPU
  x86: Really print supported CPUs if PROCESSOR_SELECT=y
  x86: Fix a bogus unwind annotation in lib/semaphore_32.S
  um, x86-64: Fix UML build after adding CFI annotations to lib/rwsem_64.S
  x86: Remove unused bits from lib/thunk_*.S
  x86: Use {push,pop}_cfi in more places
  x86-64: Add CFI annotations to lib/rwsem_64.S
  x86, asm: Cleanup unnecssary macros in asm-offsets.c
  x86, system.h: Drop unused __SAVE/__RESTORE macros
  x86: Use bitmap library functions
  x86: Partly unify asm-offsets_{32,64}.c
  x86: Reduce back the alignment of the per-CPU data section
2011-03-15 18:59:56 -07:00
Alexander van Heukelum 371c394af2 x86, binutils, xen: Fix another wrong size directive
The latest binutils (2.21.0.20110302/Ubuntu) breaks the build
yet another time, under CONFIG_XEN=y due to a .size directive that
refers to a slightly differently named (hence, to the now very
strict and unforgiving assembler, non-existent) symbol.

[ mingo:

   This unnecessary build breakage caused by new binutils
   version 2.21 gets escallated back several kernel releases spanning
   several years of Linux history, affecting over 130,000 upstream
   kernel commits (!), on CONFIG_XEN=y 64-bit kernels (i.e. essentially
   affecting all major Linux distro kernel configs).

   Git annotate tells us that this slight debug symbol code mismatch
   bug has been introduced in 2008 in commit 3d75e1b8:

     3d75e1b8        (Jeremy Fitzhardinge    2008-07-08 15:06:49 -0700 1231) ENTRY(xen_do_hypervisor_callback)   # do_hypervisor_callback(struct *pt_regs)

   The 'bug' is just a slight assymetry in ENTRY()/END()
   debug-symbols sequences, with lots of assembly code between the
   ENTRY() and the END():

     ENTRY(xen_do_hypervisor_callback)   # do_hypervisor_callback(struct *pt_regs)
       ...
     END(do_hypervisor_callback)

   Human reviewers almost never catch such small mismatches, and binutils
   never even warned about it either.

   This new binutils version thus breaks the Xen build on all upstream kernels
   since v2.6.27, out of the blue.

   This makes a straightforward Git bisection of all 64-bit Xen-enabled kernels
   impossible on such binutils, for a bisection window of over hundred
   thousand historic commits. (!)

   This is a major fail on the side of binutils and binutils needs to turn
   this show-stopper build failure into a warning ASAP. ]

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kees Cook <kees.cook@canonical.com>
LKML-Reference: <1299877178-26063-1-git-send-email-heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-12 09:02:29 +01:00
Jiri Olsa ea7145477a x86: Separate out entry text section
Put x86 entry code into a separate link section: .entry.text.

Separating the entry text section seems to have performance
benefits - caused by more efficient instruction cache usage.

Running hackbench with perf stat --repeat showed that the change
compresses the icache footprint. The icache load miss rate went
down by about 15%:

 before patch:
         19417627  L1-icache-load-misses      ( +-   0.147% )

 after patch:
         16490788  L1-icache-load-misses      ( +-   0.180% )

The motivation of the patch was to fix a particular kprobes
bug that relates to the entry text section, the performance
advantage was discovered accidentally.

Whole perf output follows:

 - results for current tip tree:

  Performance counter stats for './hackbench/hackbench 10' (500 runs):

         19417627  L1-icache-load-misses      ( +-   0.147% )
       2676914223  instructions             #      0.497 IPC     ( +- 0.079% )
       5389516026  cycles                     ( +-   0.144% )

      0.206267711  seconds time elapsed   ( +-   0.138% )

 - results for current tip tree with the patch applied:

  Performance counter stats for './hackbench/hackbench 10' (500 runs):

         16490788  L1-icache-load-misses      ( +-   0.180% )
       2717734941  instructions             #      0.502 IPC     ( +- 0.079% )
       5414756975  cycles                     ( +-   0.148% )

      0.206747566  seconds time elapsed   ( +-   0.137% )

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: masami.hiramatsu.pt@hitachi.com
Cc: ananth@in.ibm.com
Cc: davem@davemloft.net
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20110307181039.GB15197@jolsa.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-08 17:22:11 +01:00
Shaohua Li 3a09fb4570 x86: Allocate 32 tlb_invalidate_interrupt handler stubs
Add up to 32 invalidate_interrupt handlers. How many handlers are
added depends on NUM_INVALIDATE_TLB_VECTORS. So if
NUM_INVALIDATE_TLB_VECTORS is smaller than 32, we reduce code
size.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
LKML-Reference: <1295232725.1949.708.camel@sli10-conroe>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-02-14 13:03:08 +01:00
Linus Torvalds 55065bc527 Merge branch 'kvm-updates/2.6.38' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/2.6.38' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
  KVM: Initialize fpu state in preemptible context
  KVM: VMX: when entering real mode align segment base to 16 bytes
  KVM: MMU: handle 'map_writable' in set_spte() function
  KVM: MMU: audit: allow audit more guests at the same time
  KVM: Fetch guest cr3 from hardware on demand
  KVM: Replace reads of vcpu->arch.cr3 by an accessor
  KVM: MMU: only write protect mappings at pagetable level
  KVM: VMX: Correct asm constraint in vmcs_load()/vmcs_clear()
  KVM: MMU: Initialize base_role for tdp mmus
  KVM: VMX: Optimize atomic EFER load
  KVM: VMX: Add definitions for more vm entry/exit control bits
  KVM: SVM: copy instruction bytes from VMCB
  KVM: SVM: implement enhanced INVLPG intercept
  KVM: SVM: enhance mov DR intercept handler
  KVM: SVM: enhance MOV CR intercept handler
  KVM: SVM: add new SVM feature bit names
  KVM: cleanup emulate_instruction
  KVM: move complete_insn_gp() into x86.c
  KVM: x86: fix CR8 handling
  KVM guest: Fix kvm clock initialization when it's configured out
  ...
2011-01-13 10:14:24 -08:00
Gleb Natapov 631bc48782 KVM: Handle async PF in a guest.
When async PF capability is detected hook up special page fault handler
that will handle async page fault events and bypass other page faults to
regular page fault handler. Also add async PF handling to nested SVM
emulation. Async PF always generates exit to L1 where vcpu thread will
be scheduled out until page is available.

Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:23:16 +02:00
Frederic Weisbecker 625dbc3b8a x86: Save rbp in pt_regs on irq entry
From the x86_64 low level interrupt handlers, the frame pointer is
saved right after the partial pt_regs frame.

rbp is not supposed to be part of the irq partial saved registers,
but it only requires to extend the pt_regs frame by 8 bytes to
do so, plus a tiny stack offset fixup on irq exit.

This changes a bit the semantics or get_irq_entry() that is supposed
to provide only the value of caller saved registers and the cpu
saved frame. However it's a win for unwinders that can walk through
stack frames on top of get_irq_regs() snapshots.

A noticeable impact is that it makes perf events cpu-clock and
task-clock events based callchains working on x86_64.

Let's then save rbp into the irq pt_regs.

As a result with:

	perf record -e cpu-clock perf bench sched messaging
	perf report --stdio

Before:
    20.94%             perf  [kernel.kallsyms]        [k] lock_acquire
                       |
                       --- lock_acquire
                          |
                          |--44.01%-- __write_nocancel
                          |
                          |--43.18%-- __read
                          |
                          |--6.08%-- fork
                          |          create_worker
                          |
                          |--0.88%-- _dl_fixup
                          |
                          |--0.65%-- do_lookup_x
                          |
                          |--0.53%-- __GI___libc_read
                           --4.67%-- [...]

After:
    19.23%         perf  [kernel.kallsyms]    [k] __lock_acquire
                   |
                   --- __lock_acquire
                      |
                      |--97.74%-- lock_acquire
                      |          |
                      |          |--21.82%-- _raw_spin_lock
                      |          |          |
                      |          |          |--37.26%-- unix_stream_recvmsg
                      |          |          |          sock_aio_read
                      |          |          |          do_sync_read
                      |          |          |          vfs_read
                      |          |          |          sys_read
                      |          |          |          system_call
                      |          |          |          __read
                      |          |          |
                      |          |          |--24.09%-- unix_stream_sendmsg
                      |          |          |          sock_aio_write
                      |          |          |          do_sync_write
                      |          |          |          vfs_write
                      |          |          |          sys_write
                      |          |          |          system_call
                      |          |          |          __write_nocancel

v2: Fix cfi annotations.

Reported-by: Soeren Sandmann Pedersen <sandmann@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jan Beulich <JBeulich@novell.com>
2011-01-07 17:40:56 +01:00
Masami Hiramatsu de31ec8a31 x86/kprobes: Prevent kprobes to probe on save_args()
Prevent kprobes to probe on save_args() since this function
will be called from breakpoint exception handler. That will
cause infinit loop on breakpoint handling.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20101118101655.2779.2816.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18 13:40:19 +01:00
Linus Torvalds 02f36038c5 Merge branches 'softirq-for-linus', 'x86-debug-for-linus', 'x86-numa-for-linus', 'x86-quirks-for-linus', 'x86-setup-for-linus', 'x86-uv-for-linus' and 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'softirq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  softirqs: Make wakeup_softirqd static

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, asm: Restore parentheses around one pushl_cfi argument
  x86, asm: Fix ancient-GAS workaround
  x86, asm: Fix CFI macro invocations to deal with shortcomings in gas

* 'x86-numa-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, numa: Assign CPUs to nodes in round-robin manner on fake NUMA

* 'x86-quirks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: HPET force enable for CX700 / VIA Epia LT

* 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, setup: Use string copy operation to optimze copy in kernel compression

* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, UV: Use allocated buffer in tlb_uv.c:tunables_read()

* 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, vm86: Fix preemption bug for int1 debug and int3 breakpoint handlers.
2010-10-23 08:25:36 -07:00
Linus Torvalds 214515b578 Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Remove pr_<level> uses of KERN_<level>
  therm_throt.c: Trivial printk message fix for a unsuitable abbreviation of 'thermal'
  x86: Use {push,pop}{l,q}_cfi in more places
  i386: Add unwind directives to syscall ptregs stubs
  x86-64: Use symbolics instead of raw numbers in entry_64.S
  x86-64: Adjust frame type at paranoid_exit:
  x86-64: Fix unwind annotations in syscall stubs
2010-10-21 13:20:32 -07:00
Jan Beulich 3234282f33 x86, asm: Fix CFI macro invocations to deal with shortcomings in gas
gas prior to (perhaps) 2.16.90 has problems with passing non-
parenthesized expressions containing spaces to macros. Spaces, however,
get inserted by cpp between any macro expanding to a number and a
subsequent + or -. For the +, current x86 gas then removes the space
again (future gas may not do so), but for the - the space gets retained
and is then considered a separator between macro arguments.

Fix the respective definitions for both the - and + cases, so that they
neither contain spaces nor make cpp insert any (the latter by adding
seemingly redundant parentheses).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <4CBDBEBA020000780001E05A@vpn.id2.novell.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-10-19 14:28:02 -07:00
Peter Zijlstra e360adbe29 irq_work: Add generic hardirq context callbacks
Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-18 19:58:50 +02:00
Jan Beulich df5d1874ce x86: Use {push,pop}{l,q}_cfi in more places
... plus additionally introduce {push,pop}f{l,q}_cfi. All in the
hope that the code becomes better readable this way (it gets
quite a bit smaller in any case).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
LKML-Reference: <4C7FBDA40200007800013FAF@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-03 08:14:11 +02:00
Jan Beulich b1cccb1bb0 x86-64: Use symbolics instead of raw numbers in entry_64.S
... making the code a little less fragile.

Also use pushq_cfi instead of raw CFI annotations in two more
places, and add two missing annotations after stack pointer
adjustments which got modified here anyway.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
LKML-Reference: <4C7FBACF0200007800013F6A@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-03 08:14:10 +02:00
Jan Beulich 1f130a783a x86-64: Adjust frame type at paranoid_exit:
As this isn't an exception or interrupt entry point, it doesn't
have any of the hardware provide frame layouts active.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
LKML-Reference: <4C7FBAA80200007800013F67@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-03 08:14:10 +02:00
Jan Beulich e6b04b6b5a x86-64: Fix unwind annotations in syscall stubs
With the return address removed from the stack, these should
really refer to their caller's register state.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
LKML-Reference: <4C7FBA3D0200007800013F61@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-03 08:14:09 +02:00
David Howells c788732523 Mark arguments to certain syscalls as being const
Mark arguments to certain system calls as being const where they should be but
aren't.  The list includes:

 (*) The filename arguments of various stat syscalls, execve(), various utimes
     syscalls and some mount syscalls.

 (*) The filename arguments of some syscall helpers relating to the above.

 (*) The buffer argument of various write syscalls.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-13 16:53:13 -07:00
Linus Torvalds d9a73c0016 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  um, x86: Cast to (u64 *) inside set_64bit()
  x86-32, asm: Directly access per-cpu GDT
  x86-64, asm: Directly access per-cpu IST
  x86, asm: Merge cmpxchg_486_u64() and cmpxchg8b_emu()
  x86, asm: Move cmpxchg emulation code to arch/x86/lib
  x86, asm: Clean up and simplify <asm/cmpxchg.h>
  x86, asm: Clean up and simplify set_64bit()
  x86: Add memory modify constraints to xchg() and cmpxchg()
  x86-64: Simplify loading initial_gs
  x86: Use symbolic MSR names
  x86: Remove redundant K6 MSRs
2010-08-06 10:07:34 -07:00
Jeremy Fitzhardinge ca50a5f390 Merge branch 'upstream/pvhvm' into upstream/xen
* upstream/pvhvm:
  Introduce CONFIG_XEN_PVHVM compile option
  blkfront: do not create a PV cdrom device if xen_hvm_guest
  support multiple .discard.* sections to avoid section type conflicts
  xen/pvhvm: fix build problem when !CONFIG_XEN
  xenfs: enable for HVM domains too
  x86: Call HVMOP_pagetable_dying on exit_mmap.
  x86: Unplug emulated disks and nics.
  x86: Use xen_vcpuop_clockevent, xen_clocksource and xen wallclock.
  xen: Fix find_unbound_irq in presence of ioapic irqs.
  xen: Add suspend/resume support for PV on HVM guests.
  xen: Xen PCI platform device driver.
  x86/xen: event channels delivery on HVM.
  x86: early PV on HVM features initialization.
  xen: Add support for HVM hypercalls.

Conflicts:
	arch/x86/xen/enlighten.c
	arch/x86/xen/time.c
2010-08-04 14:49:16 -07:00
Brian Gerst c15a5958a0 x86-64, asm: Directly access per-cpu IST
Use a direct per-cpu reference for the IST instead of using a scratch
register.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1280594903-6341-1-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-08-01 16:05:17 -07:00
Sheng Yang 38e20b07ef x86/xen: event channels delivery on HVM.
Set the callback to receive evtchns from Xen, using the
callback vector delivery mechanism.

The traditional way for receiving event channel notifications from Xen
is via the interrupts from the platform PCI device.
The callback vector is a newer alternative that allow us to receive
notifications on any vcpu and doesn't need any PCI support: we allocate
a vector exclusively to receive events, in the vector handler we don't
need to interact with the vlapic, therefore we avoid a VMEXIT.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2010-07-22 16:45:59 -07:00
Roland McGrath 0327559151 x86: auditsyscall: fix fastpath return value after reschedule
In the CONFIG_AUDITSYSCALL fast-path for x86 64-bit system calls,
we can pass a bad return value and/or error indication for the
system call to audit_syscall_exit().  This happens when
TIF_NEED_RESCHED was set as the system call returned, so we went
out to schedule() and came back to the exit-audit fast-path.  The
fix is to reload the user return value register from the pt_regs
before using it for audit_syscall_exit().

Both the 32-bit kernel's fast path and the 64-bit kernel's 32-bit
system call fast paths work slightly differently, so that they
always leave the fast path entirely to reschedule and don't return
there, so they don't have the analogous bugs.

Reported-by: Alexander Viro <aviro@redhat.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
2010-07-21 17:44:12 -07:00
Linus Torvalds 61ecdb84c1 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix kprobes build with non-gawk awk
  x86: Split swiotlb initialization into two stages
  x86: Regex support and known-movable symbols for relocs, fix _end
  x86, msr: Remove incorrect, duplicated code in the MSR driver
  x86: Merge kernel_thread()
  x86: Sync 32/64-bit kernel_thread
  x86, 32-bit: Use same regs as 64-bit for kernel_thread_helper
  x86, 64-bit: Use user_mode() to determine new stack pointer in copy_thread()
  x86, 64-bit: Move kernel_thread to C
  x86-64, paravirt: Call set_iopl_mask() on 64 bits
  x86-32: Avoid pipeline serialization in PTREGSCALL1 and 2
  x86: Merge sys_clone
  x86, 32-bit: Convert sys_vm86 & sys_vm86old
  x86: Merge sys_sigaltstack
  x86: Merge sys_execve
  x86: Merge sys_iopl
  x86-32: Add new pt_regs stubs
  cpumask: Use modern cpumask style in arch/x86/kernel/cpu/mcheck/mce-inject.c
2009-12-16 12:02:37 -08:00
Linus Torvalds 6f696eb17b Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (57 commits)
  x86, perf events: Check if we have APIC enabled
  perf_event: Fix variable initialization in other codepaths
  perf kmem: Fix unused argument build warning
  perf symbols: perf_header__read_build_ids() offset'n'size should be u64
  perf symbols: dsos__read_build_ids() should read both user and kernel buildids
  perf tools: Align long options which have no short forms
  perf kmem: Show usage if no option is specified
  sched: Mark sched_clock() as notrace
  perf sched: Add max delay time snapshot
  perf tools: Correct size given to memset
  perf_event: Fix perf_swevent_hrtimer() variable initialization
  perf sched: Fix for getting task's execution time
  tracing/kprobes: Fix field creation's bad error handling
  perf_event: Cleanup for cpu_clock_perf_event_update()
  perf_event: Allocate children's perf_event_ctxp at the right time
  perf_event: Clean up __perf_event_init_context()
  hw-breakpoints: Modify breakpoints without unregistering them
  perf probe: Update perf-probe document
  perf probe: Support --del option
  trace-kprobe: Support delete probe syntax
  ...
2009-12-11 20:47:30 -08:00
Brian Gerst 3bd95dfb18 x86, 64-bit: Move kernel_thread to C
Prepare for merging with 32-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1260380084-3707-2-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-12-10 15:55:26 -08:00
Linus Torvalds 4646575daf Merge branch 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: UV RTC: Always enable RTC clocksource
  x86: UV RTC: Rename generic_interrupt to x86_platform_ipi
  x86: UV RTC: Clean up error handling
  x86: UV RTC: Add clocksource only boot option
  x86: UV RTC: Fix early expiry handling
2009-12-08 13:38:21 -08:00
Frederic Weisbecker b625b3b3b7 x86: Fixup wrong debug exception frame link in stacktraces
While dumping a stacktrace, the end of the exception stack won't link
the frame pointer to the previous stack.

The interrupted stack will then be considered as unreliable and ignored
by perf, as the frame pointer is unreliable itself.

This happens because we overwrite the frame pointer that links to the
interrupted frame with the address of the exception stack. This is
done in order to reserve space inside.
But rbp has been chosen here only because it is not a scratch register,
so that the address of the exception stack remains in rbp after calling
do_debug(), we can then release the exception stack space without the
need to retrieve its address again.

But we can pick another non-scratch register to do that, so that we
preserve the link to the interrupted stack frame in the stacktraces.

Just randomly choose r12. Every registers are saved just before and
restored just after calling do_debug(). And r12 is not used in the
middle, which makes it a perfect candidate.

Example: perf record -g -a -c 1 -f -e mem:$(tasklist_lock_addr):rw

Before:
    44.18%  [k] _raw_read_lock
            |
            |
            ---  |--6.31%-- waitid
                 |
                 |--4.26%-- writev
                 |
                 |--3.63%-- __select
                 |
                 |--3.15%-- __waitpid
                 |          |
                 |          |--28.57%-- 0x8b52e00000139f
                 |          |
                 |          |--28.57%-- 0x8b52e0000013c6
                 |          |
                 |          |--14.29%-- 0x7fde786dc000
                 |          |
                 |          |--14.29%-- 0x62696c2f7273752f
                 |          |
                 |           --14.29%-- 0x1ea9df800000000
                 |
                 |--3.00%-- __poll

After:

    43.94%  [k] _raw_read_lock
            |
            --- _read_lock
               |
               |--60.53%-- send_sigio
               |          __kill_fasync
               |          kill_fasync
               |          evdev_pass_event
               |          evdev_event
               |          input_pass_event
               |          input_handle_event
               |          input_event
               |          synaptics_process_byte
               |          psmouse_handle_byte
               |          psmouse_interrupt
               |          serio_interrupt
               |          i8042_interrupt
               |          handle_IRQ_event
               |          handle_edge_irq
               |          handle_irq
               |          __irqentry_text_start
               |          ret_from_intr
               |          |
               |          |--30.43%-- __select
               |          |
               |          |--17.39%-- 0x454f15
               |          |
               |          |--13.04%-- __read
               |          |
               |          |--13.04%-- vread_hpet
               |          |
               |          |--13.04%-- _xcb_lock_io
               |          |
               |           --13.04%-- 0x7f630878ce87

Note: it does not only affect perf events but also other stacktraces in
x86-64. They were considered as unreliable once we quit the debug
stack frame.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
2009-12-06 08:27:22 +01:00
Linus Torvalds ef26b1691d Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  include/linux/compiler-gcc4.h: Fix build bug - gcc-4.0.2 doesn't understand __builtin_object_size
  x86/alternatives: No need for alternatives-asm.h to re-invent stuff already in asm.h
  x86/alternatives: Check replacementlen <= instrlen at build time
  x86, 64-bit: Set data segments to null after switching to 64-bit mode
  x86: Clean up the loadsegment() macro
  x86: Optimize loadsegment()
  x86: Add missing might_fault() checks to copy_{to,from}_user()
  x86-64: __copy_from_user_inatomic() adjustments
  x86: Remove unused thread_return label from switch_to()
  x86, 64-bit: Fix bstep_iret jump
  x86: Don't use the strict copy checks when branch profiling is in use
  x86, 64-bit: Move K8 B step iret fixup to fault entry asm
  x86: Generate cmpxchg build failures
  x86: Add a Kconfig option to turn the copy_from_user warnings into errors
  x86: Turn the copy_from_user check into an (optional) compile time warning
  x86: Use __builtin_memset and __builtin_memcpy for memset/memcpy
  x86: Use __builtin_object_size() to validate the buffer size for copy_from_user()
2009-12-05 15:32:03 -08:00
Brian Gerst 97829de5a3 x86, 64-bit: Fix bstep_iret jump
This jump should be unconditional.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1257274925-15713-1-git-send-email-brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-03 20:50:02 +01:00
Ingo Molnar 4331595650 Merge branch 'perf/core' into perf/probes
Conflicts:
	tools/perf/Makefile

Merge reason:

 - fix the conflict
 - pick up the pr_*() infrastructure to queue up dependent patch

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-23 08:23:20 +02:00
Dimitri Sivanich 4a4de9c7d7 x86: UV RTC: Rename generic_interrupt to x86_platform_ipi
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20091014142257.GE11048@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-14 18:27:11 +02:00
Steven Rostedt 194ec34184 function-graph/x86: Replace unbalanced ret with jmp
The function graph tracer replaces the return address with a hook
to trace the exit of the function call. This hook will finish by
returning to the real location the function should return to.

But the current implementation uses a ret to jump to the real
return location. This causes a imbalance between calls and ret.
That is the original function does a call, the ret goes to the
handler and then the handler does a ret without a matching call.

Although the function graph tracer itself still breaks the branch
predictor by replacing the original ret, by using a second ret and
causing an imbalance, it breaks the predictor even more.

This patch replaces the ret with a jmp to keep the calls and ret
balanced. I tested this on one box and it showed a 1.7% increase in
performance. Another box only showed a small 0.3% increase. But no
box that I tested this on showed a decrease in performance by
making this change.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091013203425.042034383@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-14 08:13:53 +02:00
Brian Gerst ae24ffe5ec x86, 64-bit: Move K8 B step iret fixup to fault entry asm
Move the handling of truncated %rip from an iret fault to the fault
entry path.

This allows x86-64 to use the standard search_extable() function.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <1255357103-5418-1-git-send-email-brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-12 18:29:46 +02:00
Frederic Weisbecker d7a4b414ee Merge commit 'linus/master' into tracing/kprobes
Conflicts:
	kernel/trace/Makefile
	kernel/trace/trace.h
	kernel/trace/trace_event_types.h
	kernel/trace/trace_export.c

Merge reason:
	Sync with latest significant tracing core changes.
2009-09-23 23:08:43 +02:00
Roland McGrath b60e714dc3 x86: ptrace: sysret path should reach syscall_trace_leave
If TIF_SYSCALL_TRACE or TIF_SINGLESTEP is set while inside a syscall,
the path back to user mode should get to syscall_trace_leave.

This does happen in most circumstances.  The exception to this is on
the 64-bit syscall fastpath, when no such flag was set on syscall
entry and nothing else has punted it off the fastpath for exit.  That
one exit fastpath fails to check for _TIF_WORK_SYSCALL_EXIT flags.
This makes the behavior inconsistent with what 32-bit tasks see and
what the native 32-bit kernel always does, and what 64-bit tasks see
in all cases where the iret path is taken anyhow.

Perhaps the only example that is affected is a ptrace stop inside
do_fork (for PTRACE_O_TRACE{CLONE,FORK,VFORK,VFORKDONE}).  Other
syscalls with internal ptrace stop points (execve) already take the
iret exit path for unrelated reasons.

Test cases for both PTRACE_SYSCALL and PTRACE_SINGLESTEP variants are at:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/syscall-from-clone.c?cvsroot=systemtap
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/step-from-clone.c?cvsroot=systemtap

There was no special benefit to the sysret path's special path to call
do_notify_resume, because it always takes the iret exit path at the end.
So this change just makes the sysret exit path join the iret exit path
for all the signals and ptrace cases.  The fastpath still applies to
the plain syscall-audit and resched cases.

Signed-off-by: Roland McGrath <roland@redhat.com>
CC: Oleg Nesterov <oleg@redhat.com>
2009-09-22 20:33:42 -07:00
Ingo Molnar cdd6c482c9 perf: Do the big rename: Performance Counters -> Performance Events
Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\<event\>/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )

Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-21 14:28:04 +02:00
Jiri Olsa 4818d80942 tracing/function-graph: x86_64 stack allocation cleanup
Only 24 bytes needs to be reserved on the stack for the function graph
tracer on x86_64.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20090729085837.GB4998@jolsa.lab.eng.brq.redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 22:13:43 -04:00
Masami Hiramatsu 8222d718b3 kprobes/x86-64: Fix to move common_interrupt to .kprobes.text
Since nmi, debug and int3 returns to irq_return inside common_interrupt,
probing this function will cause int3-loop, so it should be marked
as __kprobes.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090827172325.8246.40000.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-30 03:08:27 +02:00
Steven Rostedt 71e308a239 function-graph: add stack frame test
In case gcc does something funny with the stack frames, or the return
from function code, we would like to detect that.

An arch may implement passing of a variable that is unique to the
function and can be saved on entering a function and can be tested
when exiting the function. Usually the frame pointer can be used for
this purpose.

This patch also implements this for x86. Where it passes in the stack
frame of the parent function, and will test that frame on exit.

There was a case in x86_32 with optimize for size (-Os) where, for a
few functions, gcc would align the stack frame and place a copy of the
return address into it. The function graph tracer modified the copy and
not the actual return address. On return from the funtion, it did not go
to the tracer hook, but returned to the parent. This broke the function
graph tracer, because the return of the parent (where gcc did not do
this funky manipulation) returned to the location that the child function
was suppose to. This caused strange kernel crashes.

This test detected the problem and pointed out where the issue was.

This modifies the parameters of one of the functions that the arch
specific code calls, so it includes changes to arch code to accommodate
the new prototype.

Note, I notice that the parsic arch implements its own push_return_trace.
This is now a generic function and the ftrace_push_return_trace should be
used instead. This patch does not touch that code.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-18 18:40:18 -04:00
Ingo Molnar 0d5959723e Merge branch 'linus' into x86/mce3
Conflicts:
	arch/x86/kernel/cpu/mcheck/mce_64.c
	arch/x86/kernel/irq.c

Merge reason: Resolve the conflicts above.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-11 23:31:52 +02:00
Ingo Molnar 940010c5a3 Merge branch 'linus' into perfcounters/core
Conflicts:
	arch/x86/kernel/irqinit.c
	arch/x86/kernel/irqinit_64.c
	arch/x86/kernel/traps.c
	arch/x86/mm/fault.c
	include/linux/sched.h
	kernel/exit.c
2009-06-11 17:55:42 +02:00
Linus Torvalds 8623661180 Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits)
  Revert "x86, bts: reenable ptrace branch trace support"
  tracing: do not translate event helper macros in print format
  ftrace/documentation: fix typo in function grapher name
  tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK
  tracing: add protection around module events unload
  tracing: add trace_seq_vprint interface
  tracing: fix the block trace points print size
  tracing/events: convert block trace points to TRACE_EVENT()
  ring-buffer: fix ret in rb_add_time_stamp
  ring-buffer: pass in lockdep class key for reader_lock
  tracing: add annotation to what type of stack trace is recorded
  tracing: fix multiple use of __print_flags and __print_symbolic
  tracing/events: fix output format of user stack
  tracing/events: fix output format of kernel stack
  tracing/trace_stack: fix the number of entries in the header
  ring-buffer: discard timestamps that are at the start of the buffer
  ring-buffer: try to discard unneeded timestamps
  ring-buffer: fix bug in ring_buffer_discard_commit
  ftrace: do not profile functions when disabled
  tracing: make trace pipe recognize latency format flag
  ...
2009-06-10 19:53:40 -07:00
Andi Kleen 4ef702c10b x86: fix panic with interrupts off (needed for MCE)
For some time each panic() called with interrupts disabled
triggered the !irqs_disabled() WARN_ON in smp_call_function(),
producing ugly backtraces and confusing users.

This is a common situation with machine checks for example which
tend to call panic with interrupts disabled, but will also hit
in other situations e.g. panic during early boot.  In fact it
means that panic cannot be called in many circumstances, which
would be bad.

This all started with the new fancy queued smp_call_function,
which is then used by the shutdown path to shut down the other
CPUs.

On closer examination it turned out that the fancy RCU
smp_call_function() does lots of things not suitable in a panic
situation anyways, like allocating memory and relying on complex
system state.

I originally tried to patch this over by checking for panic
there, but it was quite complicated and the original patch
was also not very popular.  This also didn't fix some of the
underlying complexity problems.

The new code in post 2.6.29 tries to patch around this by
checking for oops_in_progress, but that is not enough to make
this fully safe and I don't think that's a real solution
because panic has to be reliable.

So instead use an own vector to reboot.  This makes the reboot
code extremly straight forward, which is definitely a big plus
in a panic situation where it is important to avoid relying on
too much kernel state.  The new simple code is also safe to be
called from interupts off region because it is very very simple.

There can be situations where it is important that panic
is reliable.  For example on a fatal machine check the panic
is needed to get the system up again and running as quickly
as possible.  So it's important that panic is reliable and
all function it calls simple.

This is why I came up with this simple vector scheme.
It's very hard to beat in simplicity.  Vectors are not
particularly precious anymore since all big systems are
using per CPU vectors.

Another possibility would have been to use an NMI similar
to kdump, but there is still the problem that NMIs don't
work reliably on some systems due to BIOS issues.  NMIs
would have been able to stop CPUs running with interrupts
off too.  In the sake of universal reliability I opted for
using a non NMI vector for now.

I put the reboot vector into the highest priority bucket of
the APIC vectors and moved the 64bit UV_BAU message down
instead into the next lower priority.

[ Impact: bug fix, fixes an old regression ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-03 14:45:35 -07:00
Andi Kleen ccc3c3192a x86, mce: implement bootstrapping for machine check wakeups
Machine checks support waking up the mcelog daemon quickly.

The original wake up code for this was pretty ugly, relying on
a idle notifier and a special process flag. The reason it did
it this way is that the machine check handler is not subject
to normal interrupt locking rules so it's not safe
to call wake_up().  Instead it set a process flag
and then either did the wakeup in the syscall return
or in the idle notifier.

This patch adds a new "bootstraping" method as replacement.

The idea is that the handler checks if it's in a state where
it is unsafe to call wake_up(). If it's safe it calls it directly.
When it's not safe -- that is it interrupted in a critical
section with interrupts disables -- it uses a new "self IPI" to trigger
an IPI to its own CPU. This can be done safely because IPI
triggers are atomic with some care. The IPI is raised
once the interrupts are reenabled and can then safely call
wake_up().

When APICs are disabled the event is just queued and will be picked up
eventually by the next polling timer. I think that's a reasonable
compromise, since it should only happen quite rarely.

Contains fixes from Ying Huang.

[ solve conflict on irqinit, make it work on 32bit (entry_arch.h) - HS ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-03 14:44:05 -07:00
Yong Wang a32881066e perf_counter/x86: Remove the IRQ (non-NMI) handling bits
Remove the IRQ (non-NMI) handling bits as NMI will be used always.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <20090603051255.GA2791@ywang-moblin2.bj.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-03 09:53:34 +02:00
Andi Kleen 7856f6cce4 x86, mce: enable MCE_INTEL for 32bit new MCE
Enable the 64bit MCE_INTEL code (CMCI, thermal interrupts) for 32bit NEW_MCE.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-28 09:24:13 -07:00
Andi Kleen 5d7279268b x86, mce: use a call vector to call the 64bit mce handler
Allows to call different machine check handlers from the low
level machine check entry vector.

This is needed for later when it will be used for 32bit too.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-28 09:24:12 -07:00