Rename for_each_bit to for_each_set_bit in the kernel source tree. To
permit for_each_clear_bit(), should that ever be added.
The patch includes a macro to map the old for_each_bit() onto the new
for_each_set_bit(). This is a (very) temporary thing to ease the migration.
[akpm@linux-foundation.org: add temporary for_each_bit()]
Suggested-by: Alexey Dobriyan <adobriyan@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix missing kernel-doc notation in mtrr/main.c:
Warning(arch/x86/kernel/cpu/mtrr/main.c:152): No description found for parameter 'info'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'perf-probes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Issue at least one memory barrier in stop_machine_text_poke()
perf probe: Correct probe syntax on command line help
perf probe: Add lazy line matching support
perf probe: Show more lines after last line
perf probe: Check function address range strictly in line finder
perf probe: Use libdw callback routines
perf probe: Use elfutils-libdw for analyzing debuginfo
perf probe: Rename probe finder functions
perf probe: Fix bugs in line range finder
perf probe: Update perf probe document
perf probe: Do not show --line option without dwarf support
kprobes: Add documents of jump optimization
kprobes/x86: Support kprobes jump optimization on x86
x86: Add text_poke_smp for SMP cross modifying code
kprobes/x86: Cleanup save/restore registers
kprobes/x86: Boost probes when reentering
kprobes: Jump optimization sysctl interface
kprobes: Introduce kprobes jump optimization
kprobes: Introduce generic insn_slot framework
kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE
Fix stop_machine_text_poke() to issue smp_mb() before exiting
waiting loop, and use cpu_relax() for waiting.
Changes in v2:
- Don't use ACCESS_ONCE().
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <20100304033850.3819.74590.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (25 commits)
x86: Fix out of order of gsi
x86: apic: Fix mismerge, add arch_probe_nr_irqs() again
x86, irq: Keep chip_data in create_irq_nr and destroy_irq
xen: Remove unnecessary arch specific xen irq functions.
smp: Use nr_cpus= to set nr_cpu_ids early
x86, irq: Remove arch_probe_nr_irqs
sparseirq: Use radix_tree instead of ptrs array
sparseirq: Change irq_desc_ptrs to static
init: Move radix_tree_init() early
irq: Remove unnecessary bootmem code
x86: Add iMac9,1 to pci_reboot_dmi_table
x86: Convert i8259_lock to raw_spinlock
x86: Convert nmi_lock to raw_spinlock
x86: Convert ioapic_lock and vector_lock to raw_spinlock
x86: Avoid race condition in pci_enable_msix()
x86: Fix SCI on IOAPIC != 0
x86, ia32_aout: do not kill argument mapping
x86, irq: Move __setup_vector_irq() before the first irq enable in cpu online path
x86, irq: Update the vector domain for legacy irqs handled by io-apic
x86, irq: Don't block IRQ0_VECTOR..IRQ15_VECTOR's on all cpu's
...
* 'x86-bootmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits)
early_res: Need to save the allocation name in drop_range_partial()
sparsemem: Fix compilation on PowerPC
early_res: Add free_early_partial()
x86: Fix non-bootmem compilation on PowerPC
core: Move early_res from arch/x86 to kernel/
x86: Add find_fw_memmap_area
Move round_up/down to kernel.h
x86: Make 32bit support NO_BOOTMEM
early_res: Enhance check_and_double_early_res
x86: Move back find_e820_area to e820.c
x86: Add find_early_area_size
x86: Separate early_res related code from e820.c
x86: Move bios page reserve early to head32/64.c
sparsemem: Put mem map for one node together.
sparsemem: Put usemap for one node together
x86: Make 64 bit use early_res instead of bootmem before slab
x86: Only call dma32_reserve_bootmem 64bit !CONFIG_NUMA
x86: Make early_node_mem get mem > 4 GB if possible
x86: Dynamically increase early_res array size
x86: Introduce max_early_res and early_res_count
...
* 'acpica' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: replace acpi_integer by u64
ACPICA: Update version to 20100121.
ACPICA: Remove unused uint32_struct type
ACPICA: Disassembler: Remove obsolete "Integer64" field in parse object
ACPICA: Remove obsolete ACPI_INTEGER (acpi_integer) type
ACPICA: Predefined name repair: fix NULL package elements
ACPICA: AcpiGetDevices: Eliminate unnecessary _STA calls
ACPICA: Update all ACPICA copyrights and signons to 2010
ACPICA: Update for new gcc-4 warning options
KVM need vsyscall_init() to initialize MSR_TSC_AUX before it read the value.
Per Avi's suggestion, this patch raised vsyscall priority on hotplug notifier
chain, to 30.
CC: Ingo Molnar <mingo@elte.hu>
CC: linux-kernel@vger.kernel.org
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, uv: Remove recursion in uv_heartbeat_enable()
x86, uv: uv_global_gru_mmr_address() macro fix
x86, uv: Add serial number parameter to uv_bios_get_sn_info()
* 'x86-pci-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Enable NMI on all cpus on UV
vgaarb: Add user selectability of the number of GPUS in a system
vgaarb: Fix VGA arbiter to accept PCI domains other than 0
x86, uv: Update UV arch to target Legacy VGA I/O correctly.
pci: Update pci_set_vga_state() to call arch functions
* 'x86-numa-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, numa: Remove configurable node size support for numa emulation
x86, numa: Add fixed node size option for numa emulation
x86, numa: Fix numa emulation calculation of big nodes
x86, acpi: Map hotadded cpu to correct node.
* 'x86-mtrr-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Convert set_atomicity_lock to raw_spinlock
x86, mtrr: Kill over the top warn
x86, mtrr: Constify struct mtrr_ops
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, mm: Unify kernel_physical_mapping_init() API
x86, mm: Allow highmem user page tables to be disabled at boot time
x86: Do not reserve brk for DMI if it's not going to be used
x86: Convert tlbstate_lock to raw_spinlock
x86: Use the generic page_is_ram()
x86: Remove BIOS data range from e820
Move page_is_ram() declaration to mm.h
Generic page_is_ram: use __weak
resources: introduce generic page_is_ram()
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, cacheinfo: Enable L3 CID only on AMD
x86, cacheinfo: Remove NUMA dependency, fix for AMD Fam10h rev D1
x86, cpu: Print AMD virtualization features in /proc/cpuinfo
x86, cacheinfo: Calculate L3 indices
x86, cacheinfo: Add cache index disable sysfs attrs only to L3 caches
x86, cacheinfo: Fix disabling of L3 cache indices
intel-agp: Switch to wbinvd_on_all_cpus
x86, lib: Add wbinvd smp helpers
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (28 commits)
ftrace: Add function names to dangling } in function graph tracer
tracing: Simplify memory recycle of trace_define_field
tracing: Remove unnecessary variable in print_graph_return
tracing: Fix typo of info text in trace_kprobe.c
tracing: Fix typo in prof_sysexit_enable()
tracing: Remove CONFIG_TRACE_POWER from kernel config
tracing: Fix ftrace_event_call alignment for use with gcc 4.5
ftrace: Remove memory barriers from NMI code when not needed
tracing/kprobes: Add short documentation for HAVE_REGS_AND_STACK_ACCESS_API
s390: Add pt_regs register and stack access API
tracing/kprobes: Make Kconfig dependencies generic
tracing: Unify arch_syscall_addr() implementations
tracing: Add notrace to TRACE_EVENT implementation functions
ftrace: Allow to remove a single function from function graph filter
tracing: Add correct/incorrect to sort keys for branch annotation output
tracing: Simplify test for function_graph tracing start point
tracing: Drop the tr check from the graph tracing path
tracing: Add stack dump to trace_printk if stacktrace option is set
tracing: Use appropriate perl constructs in recordmcount.pl
tracing: optimize recordmcount.pl for offsets-handling
...
* 'core-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
generic-ipi: Optimize accesses by using DEFINE_PER_CPU_SHARED_ALIGNED for IPI data
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
plist: Fix grammar mistake, and c-style mistake
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
kprobes: Add mcount to the kprobes blacklist
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86_64: Print modules like i386 does
* 'x86-doc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Put 'nopat' in kernel-parameters
* 'x86-gpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86-64: Allow fbdev primary video code
* 'x86-rlimit-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Use helpers for rlimits
Iranna D Ankad reported that IBM x3950 systems have boot
problems after this commit:
|
| commit b9c61b7007
|
| x86/pci: update pirq_enable_irq() to setup io apic routing
|
The problem is that with the patch, the machine freezes when
console=ttyS0,... kernel serial parameter is passed.
It seem to freeze at DVD initialization and the whole problem
seem to be DVD/pata related, but somehow exposed through the
serial parameter.
Such apic problems can expose really weird behavior:
ACPI: IOAPIC (id[0x10] address[0xfecff000] gsi_base[0])
IOAPIC[0]: apic_id 16, version 0, address 0xfecff000, GSI 0-2
ACPI: IOAPIC (id[0x0f] address[0xfec00000] gsi_base[3])
IOAPIC[1]: apic_id 15, version 0, address 0xfec00000, GSI 3-38
ACPI: IOAPIC (id[0x0e] address[0xfec01000] gsi_base[39])
IOAPIC[2]: apic_id 14, version 0, address 0xfec01000, GSI 39-74
ACPI: INT_SRC_OVR (bus 0 bus_irq 1 global_irq 4 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 5 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 3 global_irq 6 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 4 global_irq 7 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 6 global_irq 9 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 7 global_irq 10 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 8 global_irq 11 low edge)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 12 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 12 global_irq 15 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 13 global_irq 16 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 14 global_irq 17 low edge)
ACPI: INT_SRC_OVR (bus 0 bus_irq 15 global_irq 18 dfl dfl)
It turns out that the system has three io apic controllers, but
boot ioapic routing is in the second one, and that gsi_base is
not 0 - it is using a bunch of INT_SRC_OVR...
So these recent changes:
1. one set routing for first io apic controller
2. assume irq = gsi
... will break that system.
So try to remap those gsis, need to seperate boot_ioapic_idx
detection out of enable_IO_APIC() and call them early.
So introduce boot_ioapic_idx, and remap_ioapic_gsi()...
-v2: shift gsi with delta instead of gsi_base of boot_ioapic_idx
-v3: double check with find_isa_irq_apic(0, mp_INT) to get right
boot_ioapic_idx
-v4: nr_legacy_irqs
-v5: add print out for boot_ioapic_idx, and also make it could be
applied for current kernel and previous kernel
-v6: add bus_irq, in acpi_sci_ioapic_setup, so can get overwride
for sci right mapping...
-v7: looks like pnpacpi get irq instead of gsi, so need to revert
them back...
-v8: split into two patches
-v9: according to Eric, use fixed 16 for shifting instead of remap
-v10: still need to touch rsparser.c
-v11: just revert back to way Eric suggest...
anyway the ioapic in first ioapic is blocked by second...
-v12: two patches, this one will add more loop but check apic_id and irq > 16
Reported-by: Iranna D Ankad <iranna.ankad@in.ibm.com>
Bisected-by: Iranna D Ankad <iranna.ankad@in.ibm.com>
Tested-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: len.brown@intel.com
LKML-Reference: <4B8A321A.1000008@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that both Xen and VMI disable allocations of PTE pages from high
memory this paravirt op serves no further purpose.
This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
highpte pages".
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
LKML-Reference: <1267204562-11844-3-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria <akataria@vmware.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Preventing HIGHPTE allocations under VMI will allow us to remove the
kmap_atomic_pte paravirt op.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
LKML-Reference: <1267204562-11844-2-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria <akataria@vmware.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Merge commit aef55d4922 mis-merged io_apic.c so we lost the
arch_probe_nr_irqs() method.
This caused subtle boot breakages (udev confusion likely
due to missing drivers) with certain configs.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20100207210250.GB8256@jenkins.home.ifup.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Enable NMI on all cpus in UV system and add an NMI handler
to dump_stack on each cpu.
By default on x86 all the cpus except the boot cpu have NMI
masked off. This patch enables NMI on all cpus in UV system
and adds an NMI handler to dump_stack on each cpu. This
way if a system hangs we can NMI the machine and get a
backtrace from all the cpus.
Version 2: Use x86_platform driver mechanism for nmi init, per
Ingo's suggestion.
Version 3: Clean up Ingo's nits.
Signed-off-by: Russ Anderson <rja@sgi.com>
LKML-Reference: <20100226164912.GA24439@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Split amd,p6,intel into separate files so that we can easily deal with
CONFIG_CPU_SUP_* things, needed to make things build now that perf_event.c
relies on symbols from amd.c
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We re-program the event control register every time we reset the count,
this appears to be superflous, hence remove it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since the cpu argument to hw_perf_group_sched_in() is always
smp_processor_id(), simplify the code a little by removing this argument
and using the current cpu where needed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1265890918.5396.3.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds correct AMD NorthBridge event scheduling.
NB events are events measuring L3 cache, Hypertransport traffic. They are
identified by an event code >= 0xe0. They measure events on the
Northbride which is shared by all cores on a package. NB events are
counted on a shared set of counters. When a NB event is programmed in a
counter, the data actually comes from a shared counter. Thus, access to
those counters needs to be synchronized.
We implement the synchronization such that no two cores can be measuring
NB events using the same counters. Thus, we maintain a per-NB allocation
table. The available slot is propagated using the event_constraint
structure.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4b703957.0702d00a.6bf2.7b7d@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In certain situations, the kernel may need to stop and start the same
event rapidly. The current PMU callbacks do not distinguish between stop
and release (i.e., stop + free the resource). Thus, a counter may be
released, then it will be immediately re-acquired. Event scheduling will
again take place with no guarantee to assign the same counter. On some
processors, this may event yield to failure to assign the event back due
to competion between cores.
This patch is adding a new pair of callback to stop and restart a counter
without actually release the underlying counter resource. On stop, the
counter is stopped, its values saved and that's it. On start, the value
is reloaded and counter is restarted (on x86, actual restart is delayed
until perf_enable()).
Signed-off-by: Stephane Eranian <eranian@google.com>
[ added fallback to ->enable/->disable for all other PMUs
fixed x86_pmu_start() to call x86_pmu.enable()
merged __x86_pmu_disable into x86_pmu_stop() ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4b703875.0a04d00a.7896.ffffb824@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce x86 arch-specific optimization code, which supports
both of x86-32 and x86-64.
This code also supports safety checking, which decodes whole of
a function in which probe is inserted, and checks following
conditions before optimization:
- The optimized instructions which will be replaced by a jump instruction
don't straddle the function boundary.
- There is no indirect jump instruction, because it will jumps into
the address range which is replaced by jump operand.
- There is no jump/loop instruction which jumps into the address range
which is replaced by jump operand.
- Don't optimize kprobes if it is in functions into which fixup code will
jumps.
This uses text_poke_multibyte() which doesn't support modifying
code on NMI/MCE handler. However, since kprobes itself doesn't
support NMI/MCE code probing, it's not a problem.
Changes in v9:
- Use *_text_reserved() for checking the probe can be optimized.
- Verify jump address range is in 2G range when preparing slot.
- Backup original code when switching optimized buffer, instead of
preparing buffer, because there can be int3 of other probes in
preparing phase.
- Check kprobe is disabled in arch_check_optimized_kprobe().
- Strictly check indirect jump opcodes (ff /4, ff /5).
Changes in v6:
- Split stop_machine-based jump patching code.
- Update comments and coding style.
Changes in v5:
- Introduce stop_machine-based jump replacing.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133446.6725.78994.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add generic text_poke_smp for SMP which uses stop_machine()
to synchronize modifying code.
This stop_machine() method is officially described at "7.1.3
Handling Self- and Cross-Modifying Code" on the intel's
software developer's manual 3A.
Since stop_machine() can't protect code against NMI/MCE, this
function can not modify those handlers. And also, this function
is basically for modifying multibyte-single-instruction. For
modifying multibyte-multi-instructions, we need another special
trap & detour code.
This code originaly comes from immediate values with
stop_machine() version. Thanks Jason and Mathieu!
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133438.6725.80273.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The code in stop_machine that modifies the kernel text has a bit
of logic to handle the case of NMIs. stop_machine does not prevent
NMIs from executing, and if an NMI were to trigger on another CPU
as the modifying CPU is changing the NMI text, a GPF could result.
To prevent the GPF, the NMI calls ftrace_nmi_enter() which may
modify the code first, then any other NMIs will just change the
text to the same content which will do no harm. The code that
stop_machine called must wait for NMIs to finish while it changes
each location in the kernel. That code may also change the text
to what the NMI changed it to. The key is that the text will never
change content while another CPU is executing it.
To make the above work, the call to ftrace_nmi_enter() must also
do a smp_mb() as well as atomic_inc(). But for applications like
perf that require a high number of NMIs for profiling, this can have
a dramatic effect on the system. Not only is it doing a full memory
barrier on both nmi_enter() as well as nmi_exit() it is also
modifying a global variable with an atomic operation. This kills
performance on large SMP machines.
Since the memory barriers are only needed when ftrace is in the
process of modifying the text (which is seldom), this patch
adds a "modifying_code" variable that gets set before stop machine
is executed and cleared afterwards.
The NMIs will check this variable and store it in a per CPU
"save_modifying_code" variable that it will use to check if it
needs to do the memory barriers and atomic dec on NMI exit.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This will save 64K bytes from memory when loading linux if DMI is
disabled, which is good for embedded systems.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
LKML-Reference: <1265758732-19320-1-git-send-email-cascardo@holoscopio.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
init_fpu() already ensures that the used_math() is set for the stopped child.
Remove the redundant set_stopped_child_used_math() in [x]fpregs_set()
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100222225240.642169080@sbs-t61.sc.intel.com>
Acked-by: Rolan McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
48 bytes (bytes 464..511) of the xstateregs payload come from the
kernel defined structure (xstate_fx_sw_bytes). Rest comes from the
xstate regs structure in the thread struct. Instead of having multiple
user_regset_copyout()'s, simplify the xstateregs_get() by first
copying the SW bytes into the xstate regs structure in the thread structure
and then using one user_regset_copyout() to copyout the xstateregs.
Requested-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100222225240.494688491@sbs-t61.sc.intel.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Merge reason:
Conflicts in arch/x86/kernel/apic/io_apic.c
Resolved Conflicts:
arch/x86/kernel/apic/io_apic.c
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Merge reason: conflict in arch/x86/kernel/apic/io_apic.c
Resolved Conflicts:
arch/x86/kernel/apic/io_apic.c
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
